Research ArticleSeismic Performance Evaluation of Buried SewageCollection Pipelines

Abolfazl Rahimi1 and Mohammad Rezaii 2

1Department of Civil Engineering Islamic Azad University Gorgan Iran2Department of Civil Engineering NIT Babol Iran

Correspondence should be addressed to Mohammad Rezaii rezaiiabfagolestanir

Received 26 November 2020 Revised 16 December 2020 Accepted 15 January 2021 Published 29 January 2021

Academic Editor Seyed Mahdi Seyed Kolbadi

Copyright copy 2021Abolfazl Rahimi andMohammad Rezaiiis is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in anymedium provided the original work isproperly cited

One of the systems which is damaged because of earthquake is an urban wastewater network In this paper it is tried to study thedamages occurred on urban wastewater networks in a selected network e most important definitions by the network aboutsome branches of the wastewater network and relevant reformations are studied en the function of pipeline networks buriedby the previous earthquake is studied and also it is proceeded about the research studies done regarding the relationshipsdominant on susceptibility in which some of the mentioned relationships are studiede statistical society of somemethods usedin this research is studied and the software applied in this part is introduced Finally the data of the output results are analysed inwhich the results obtained by this research are including the output drawings of the software GIS that demonstrate the occurreddamages in applied and clear way Some suggestions for using the aforesaid results by the researchers and authorities especiallydisaster headquarter have been presented e results of this study showed that the assumptions and also the modelling processhave handled the simulation well and this process is an effective method in decision making

1 Introduction

Lifeline refers to a set of structures facilities and installationwhich play a pivotal role in storing supplying transferringand distributing basic necessities such as water electricityand gas or collecting storing purifying and recyclingwastewater and other trash or evenmaking communicationsuch as landline cell phone Internet and data [1] As theirnames suggest broadness and continuous performance aredefining characteristics of such structures as mentioned inFigure 1 [2]

ese structures share common features Obviouslylifeline function a significant performance in the city andsupply basic necessities As an illustration of this thewastewater system is a most important lifeline Raw sewagealways has a great deal of matters having detrimental effectson beings which would result in even unknown infectiousdiseases for example pestilence and cholera In additioncombination of sewer gases such as methane ethane and

benzene with air increases the likelihood of explosion [3] Ingeneral speaking there are two analytical and statistic ap-proaches to studying susceptibility of underground pipelineswhen it comes to earthquake As such the analytical viewaims to present relations in order to find strain in pipesthrough physical laws Considering this view recent liter-ature is setting out to find how such seismic parameters suchas MMI PG and PGV bring about destruction A sewagesystem is made up of linear and stationary structures(Figure 2)

e sewage system pipelines are classified into sevengroups By moving from top to down the importance anddiameter of pipes are decreased Table 1 illustrates theclassification It is worth mentioning that material of pipeshas dramatically affected last earthquake data As fittings ofthe sewage system have not been made to endure pressurethey are weak Rigid fittings refer to those that avoid twoadjacent parts from displacement at the end while flexiblefittings allow two adjacent parts to locally rotate or transfer

HindawiShock and VibrationVolume 2021 Article ID 6669505 12 pageshttpsdoiorg10115520216669505

Sewage pipes and fittings are commonly made up of ceramicconcrete cement asbestos plastic poly ethylene UPVCGRP cast iron and steel

Iran is located on the Alp belt extending from the AlpsMountains to the Mediterranean Sea Iranrsquos plate consisted ofIran Arabian and Eurasian plates Arabian plate pulls that ofIran Zagros pressure region as well as mountains shows acommon boundary between the two plates which has resultedin reverse faults On the other hand Iranrsquos plate is surroundedby the Eurasian Indian and Anatolian plates from the northeast and west respectively As such pressure arising from theArabian plate prevents Iranian plate from any transfer

According to the Lifeline Earthquake EngineeringCouncil founded by the US Civil Engineering Council in1974 it has been estimated that almost half of pipelines inIran are at the risk of bursting in case of happening anearthquakes On the other hand although behaviour ofground pipelines has been studied during 10 last years thereis much room for argumente direct relationship betweenthe sewage system and public health on the one hand andhaving difficulty in finding location of leakage and breakagein pipes due to force of gravity in the sewage system after anearthquake taken place on the other hand attaches im-portance to study susceptibility of the system In additionconsidering depth of the sewage system replacing and fixingdamaged pipes would be extremely costly So far a lot ofresearch has been done on the different functions of buriedpipes ese studies have been conducted to better identifythe behaviours of these sensitive infrastructures In thisstudy the behaviour of these structures in the face ofearthquake force for a relatively large area has beenevaluated

2 Literature Review

According to this analytical method the results offered byChu and Shah [4] as well as Goodling and Iqbal [5] suggestthat inlet and outlet branches of the bended pipes seemed tobe flexible but the sag assumed rigid that is to say theyconsidered no relative rotation resulting from bending

Figure 1 Scheme of lifelines

Municipal Conventionalwastewatertreatment

Treatment asneeded for reuse

Treatment asneeded for reuse

Sludge treatment

Other reuseopportunities

Treatedwastewater

Sludge

Eff luent

Eff luentdischarge to

surface waters

Sludge Treatedsludge

Other reuseopportunitiesSludge

disposal

wastewater

Figure 2 e scheme of a sewage system

Table 1 Classification of the sewage system parts into linear andstationary

Type of the sewagesystem component Title of component

Stationary Installation of sewage storage includingsurface and ground basins

Stationary Installation for pumping

Linear Pipelines and ground main transfertunnel

Stationary Sewage-treatment plantLinear Pipelines for collecting sewageStationary Manhole

Stationary Administrative public and supportingbuildings

Stationary Water and wastewater subscribers

2 Shock and Vibration

between inlet and outlet tangents Moreover relocationarising from slipping (Δ) measured by subtracting the re-location of a piece of pipe (pΔ) from relocation of soil (sΔ)Although the previous method assumed bending rigid theretends to be some transformations in sags creating tendencyto decrease in flexural moment

Goodling [5] put forward equations based on analysingbending in thin-walled curved pipes In a research study [6]suggested a method for predicting relocation of the sag inwhich the Riley wave was assumed as a transmittal sine wavewith limited wave length In the same token relocation of thepipe was assumed equal to that of ground where displace-ment of ground was zero and they developed a simpleequation for pipe strain in the point of sags based on cor-respondent structural analyses ey assumed effectivelength (Lprime) one-fourth of the wave length so anchors couldbe measured by virtue of displacement compatibilityequations in the curve

Takada and Tanabe [7] put forward knee and T-joints aremore susceptible to damage than other parts of a pipelineand maximum tensile pressure can affect them In 2003OrsquoRourke and McLaughlin developed a two-dimensionalfinite-element model as their PhD dissertation ey entereda quasistatic sine Riley wave into the numerical model andcompared results obtained from a steel pipe having a di-ameter and thickness of 24 and 5 inch in a sand soil with areduction factor (06) with that of obtained by Shah and Chu[4] as well as [6] for a flat surface steel

Moreover OrsquoRourke and Jeon [1] utilized a finite-ele-ment model developed in Nastran software to stimulate theproblem and comparing analytical resultsey assumed thepipe as a column element for modelling and each bendinghad a length of 125meters equal to one-fourth of a wavelength having 500meters To verify this model data collectedfrom the analytical method were compared with that of thefinite-element model So it was found that results obtainedfrom the analytical method were almost better in all cases Ascan be seen from prior works most of numerical analysesconcerning were quasistatic however studies on dynamicbehaviour of pipe under earthquake loading are still lacking

In 2008 F R Rofooei and R Qorbani did a research oncontinuous pipes assuming vertical wave propagation andthen compared obtained strain results with that of observedin a pipe having a knee-joint Results showed that the ex-istent sag led to an increase in strain and pressure in theknee-joint than a continuous pipe Moreover Takada et al[8] did a numerical research on a set of pipes combining Tand knee-joint and showed that the seismic behaviour of apipe network was more than a continuous one In additionadjacent pipes showed inconsiderable increased behaviourthan patchy ones

Dai et al [9] studied about analysis and comparison oflong-distance pipeline failures and they found that accordingto the statistical results PNGPC is not very far compared withforeign countries ere are still some aspects both in tech-nology and in management that should be improved such asquality of manufacture and construction of pipeline andthird-party monitoring Also Yang et al [10] did researchabout numerical simulation of pipeline-pavement damage

caused by explosion of leakage gas in buried pipelines andshowed that the results can provide theoretical basis formunicipal pipeline construction design and urban safetyplanning and provide references for the risk assessment of gasexplosion in buried pipelines

21 New Zealand Earthquake Christchurch is New Zea-landrsquos second biggest city Its sewage system covers almost150000 families Although the system is made up of con-crete ceramic UPVC and asbestos pipes it has a highpercentage of concrete one An earthquake measuring 71 onthe Richter scale hit the city on 4th September 2010 (Fig-ure 3) e sewage system was badly destroyed Demolitionrate of pipes made up of concrete and reinforced concrete(09) increases the likelihood of corrosion [11]

22 JapanEarthquakes An earthquakemeasuring 68 on theRichter scale called Nigata-Ken Chuetsu hit the city inOctober 2004 Destruction of the sewage-treatment plant ledto flow of raw sewage into the city to such an extent that151 kilometer sewage pipeline was destroyed and 2056manholes were also damaged e greatest damage recordedfor tucking water behindmanholes and pipes which not onlygenerated heavy traffic but also caused failure to pumphousesrsquo sewage Another earthquake measuring 75 on theRichter scale hit Nigata Japan on 16th January 1964 Over470 km pipeline namely 68 of pipes is damagedemostdestruction was recorded for cast iron pipes and jointsAccording to data other pipes especially those with smalldiameter showed more damage due to bending Many pipesand installation became visible on the ground because of soilliquefaction In addition slope of the soil is also consideredas an important factor in damages [12]

23 Manjil Earthquake Iran (1990) An earthquake hitRodbar and Manjil Iran on 21st July 1990 It caused severedamage to several buildings roads installation and even theSefidrood concrete dam [13] ere are still insufficient datafor the extent of damage to the water supply system Al-though buildingsrsquo water pipes had been badly damagedmain pipelines of the city water supply system were in asatisfactory condition thanks to putting new pipes in depth(Figure 4)

24 Bam Earthquake (2003) An earthquake measuring 68on the Richter scale struck Bam Iran on 26 December 2003e city had a total population of 12000 According to re-ports asbestos fittings of pipes had been damaged but themain water supply system was slightly damaged [14] Al-though water gushed from broken domestic pipes watertanks were not badly damaged mainly because they wereunderground (Figure 5)

3 Material and Methods

31 Effective Factors Causing Damage to Pipelines after Oc-currence of anEarthquake Multiple parameters have impact

Shock and Vibration 3

on damage to underground pipelines after occurring anearthquake In general characteristics of a pipeline soiland magnitude of an earthquake affect the seismic be-haviour of the pipeline As such there are considerablefactors having effect on the seismic behaviour of buriedpipelines In a research Eguchi et al studied factors af-fecting susceptibility of buried pipelines when an earth-quake happens through analysing damage to the buildingsdestroyed in the San Francisco earthquake [15] Evidencesuggested that the devastating effect of faulting was muchmore than distortion due to earthquake movements As aresult the closer a building is to the fault the worse it wouldbe destroyed A pipeline would be inevitably face to moredangers due to its extent than other installations whichcover a small area simply because long pipelines are spreadover regions having active faults or soil liquefaction eterm faulting is meant fracture of faults which is happenedon the ground ere are three main types of faultingincluding horizontal vertical or a combination of themInstallations located on the fault line are much moresusceptible to the earthquake (Figure 6)

Figure 6 shows an ideal structural model on a fault lineand the probability and extent of soil liquefaction will in-crease by increase in the continuance in earthquake Soilliquefaction as well as lateral movements is viewed asdevastating parameters which may lead to bury surfacestructures under soil or help underground structures tobecome visible Shaking cause to compress soil and sub-sidence is occurred However the extent of persistent

Figure 4 Damage occurred from Manjil earthquake

Figure 5 Damage occurred from Bam earthquake

Fault trace

500 m 500 m

Y

A

X

B C C

D

E EOβ

δf

Figure 6 Ideal structural model during faulting

0

02

04

06

08

1

AC CI CLS CONC EW HDPE MPVC PVC RCRR UPVC

Damage rate

Figure 3 Demolition rate of pipelines considering their type in the New Zealand earthquake

4 Shock and Vibration

relocation due to subsidence is less than that of due to soilliquefaction Notwithstanding subsidence is of importancebecause of making heterogeneous dislocations in soil

32 Features of the Pipeline Affecting Susceptibility of theBuried Pipelines due to an Earthquake Most of parametersaffecting susceptibility of buried pipelines due to anearthquake have much to do with characteristics of thepipeline Prior studies showed that type of the pipe plays apivotal role To put it simply its flexibility helps the pipingsystem because it leads to easily movement of soil along withthe pipe which prevent the pipe from bursting during anearthquake Increase in the internal diameter of pipelinesdecreases both bending and axial tensions due to affectingsoil-pipe interaction Final conditions have marginal effecton tensions created in cross sections when it comes to lengthof pipe With regard to data collected from the analysis it ishighly likely that the pipe will rupture at its junction withother installations such as manholes and storages thanother sections of the pipeline (Figure 7ndash9)

e pipeline bears lateral loads during an earthquakewhich it oscillates pipes and cuts their connections with thesaddle However bracing spaces helps the system not to bedevastated Figure 10 illustrates demolition of pipesrsquo supportdue to soil liquefaction in the Northbridge earthquake(1994)

However seismic and flexible joints have been found tosuggest great function during an earthquake which it leads todecrease in demolition of the water supply system On theother hand accruing to data collected from prior researchcontinuous pipes such as the ones made up of steel withwelded joints have shown greater function than sectionalpipes with lots of joints In addition the extent of demolitionobserved for asbestos pipes in Loma Prieta (1989) andNorthridge (1994) earthquakes was less than that recordedfor Mexico City earthquake (1985)

Researchers also argue that connection behaviour wouldprove to be linear when pipesrsquo relative rotation is 005 radianMoreover bending experiments on fittings used in flexiblecast iron pipes having rubber-made washers and differentdiameters showed that rotation of joints is done around thepipe Improper hardness distribution is the leading cause ofmost of the destructions of the water supply system As aresult relocations arising from such shakes are different andcause to break joints between pipes (Figures 11 and 12)

33 Methods of Studying the Seismic Behaviour of a PipelineWith regard to the destructions left after earthquakes re-searchers set the stage to conduct a comprehensive study inorder to develop some methods to find how seismic be-haviour affects the pipelines e methods are generallydivided into three groups including approximate analysis[16] accurate analysis and building code methods Shakesarising from an earthquake go through many changes due toseveral reasons before happening which will affect structuresin different ways Initial works in the field of buried pipelinesfocused preliminary on the main factor that is to say thepath through which waves move In addition as can be seen

from numerical calculations its effect has been considered inthe form of a semistatic factor

Regarding dynamic analyses done on buried pipelinesespecially on their bending points the impact of this factorhas omitted and pipes were only analysed by taking verticaldistribution and synchronous shakes throughout all pointsinto account Wave propagation velocity functions as aleading parameter to calculate strain Shear wave velocitywas used to calculate the extent of axial strain in areas having

0

500

1000

1500

2000

2500

3000

0 50 100 150 200

Bend

ing

tens

ion

Length (m)

Figure 7 Variation in the extent of maximum bending tensionsalong the pipeline with different final conditions

0

1000

2000

3000

4000

5000

0 50 100 150 200 250 300

Bend

ing

tens

ion

Length (m)

Figure 8 Variation in the extent of maximum axial tensions alongthe pipeline with different final conditions

0

1000

2000

3000

4000

5000

0 50 100 150 200

Bend

ing

tens

ion

Length (m)

Figure 9 Variation in the extent of maximum axial tensions alongthe pipeline with different final conditions

Shock and Vibration 5

focal length less than five times of the distance from focaldepth to the epicentre of an earthquake while Riley wavevelocity was utilized to calculate distances more than givenamount In a research study OrsquoRourke et al studied hori-zontal apparent speed for body waves ey developed ananalytical method to assess the shear wave angle of incidentSo apparent speed for shear waves is calculated as

Cs - apparent cs

sin θ (1)

where θ is the incident angle of the shear wave to thehorizontal and Cs is the velocity of shear waves in surfacesoil Phase velocity of the wave is the same apparent velocityUnlike body waves phase velocity depends upon frequencyWith regard to the Riley wave there is relation among wavelength (λ) frequency and phase velocity Figure 13ndash15 il-lustrate a scheme of Riley wave propagation with an ap-parent velocity

Wave propagation has been found to put strain on theground Measuring strain of ground is done by studyingsimple transitional movement of a wave having fixed shapeIt was assumed that velocity and movement of two pointsthroughout a propagation path simply differ in a time lag inwhich in turn it is a function of the distance between twopoints and the seismic wave velocity In the same tokenmaximum tensile or compressive strain of the earth (gє) inthe direction of wave propagation is measured as

εg VmC

(2)

where Vm is themaximum horizontal velocity of the earth inthe direction of wave propagation and C is the apparentpropagation velocity of the seismic wave To propagate aRiley wave strain parallel with the ground could be mea-sured using the equation above where C is replaced by thevalue of phase velocity according to the wave lengthequivalent to four times of the separation distance (thelength of the pipe located between two bridles which is aboutto analyse) e equation needs to be changed when thegiven direction is parallel to the line of wave propagationGenerally as can be seen from the figure below the wave hasangle in both vertical and horizontal plates So the equation

Figure 10 Demolition of pipesrsquo support due to soil liquefaction inthe Northbridge earthquake (1994)

Figure 11 Cracks observed in the joint between a restrained weakpipe and an unrestrained one [11]

Figure 12 Cracks in the pipe connected to the storage (ALA 2002)

P wave

S wave

Low wave

Rayleigh wave

Compression

Tension

Figure 13 Comparing R and S waves in designing pipes

Apparent velocity vax

True velocity V

Mrsquo Mrsquorsquo

M

θ

θ

z

x

Figure 14 Apparent propagation of a shear wave

6 Shock and Vibration

below is used to measure apparent wave velocity in thedirection of pipersquos axis

Cs - apparent cs

sin θ middot cos c (3)

Yeh [17] illustrated that maximum strain of the earth ismeasured by 45 θ c in given plates

34 Studying Seismic Behaviour of a Soil-Pipe System con-cerning Continuous Buried Pipelines A structure bearsbending or axial transformations after an earthquakeProviding satisfying plasticity in order to absorb transfor-mations due to earthquake without decrease in static loadingcapacity acts as an important design criterion Generallydeveloped axial strain throughout a continuous direct pipedepends upon such factors as shape of the earth transmittalwave length and soil-pipe interaction forces Althoughstrain of pipe and soil are assumed equal for small- tomedium-sized movements the same is not true for greatstrains because of existent slipping between soil and pipe Ithas been found to decrease pipe strain compared to that ofsoil Newmark [16] put forward a simple method to de-termine how the pipeline acts when earthquake waves arepropagated en other researchers such as Yeh revised it

Seismic movement of the earth which is defined as thehistory of velocity-time and velocity-displacement func-tions as a transmittal wave with fixed shape It suggests thattwo points along the propagation path simply shake by atime lag Inertia involved in small movement equations istoo small to be measured Later the assumption was studiedby many researchers and their works showed that it acts as areasonable engineering approximation It is assumed that norelative movement happens in the soil-pipe interaction andpipersquos strain equals to that of soil In addition OrsquoRourke andEl Hamadi developed an analytical method to estimatemaximum pipe strain

e method assumes that first axial strain in soil equalspipe strain arising from length friction between soil and pipeand second waves are propagated parallel to the axis of pipeIn a research study OrsquoRourke and Jeon [1] compared data

collected from three mentioned analytical methods when itcame to the continuous pipeline under the Riley waversquospropagation Besides the model put forward by Takada [18]suggested that pipe is modelled in the form of a shell having alength of 60 D adjacent to the fault but it could be in theform of an beam element where the distance from the pipe tothe fault is almost 300meters and the extent of soil and pipeslipping and strains are insignificant (Figure 16) All thingsbeing equal soil surrounded the pipe is modelled using soilsprings according to the seismic designing regulation ofburied oil and gas pipes [19]

In 2004 Takada et al reported on a newmodel accordingto changes in boundary conditions ey suggest that thepipe should be modelled in the junction with the fault in theform of a shell element due to local strain and big trans-formations just the same as before Moreover each point ofthe shell element is connected to three soil springs in axiallateral and vertical directions Finally the relation betweenthe axial force (f ) and increased length ΔL which is regardedto boundary conditions for nonelastic springs is measuredas

F(ΔL)

3EAfs2

1113970U016ΔL

23 0ltΔLltU0 (4)

3EAfsΔL minus 14U0

1113874 1113875

1113970σy2A2Efs

+U04

(5)

where Yσ acts as pipersquos yield stress and elasticity modulus Ithas been suggested that tensile rupture local buckling andthimble buckling are among the most significant damage tocontinuous pipes while tensile and compression ruptures ofpipe joints as well as local bending were the most commondamage observed in apart pipeline [20] Concerning mod-elling of continuous pipes Halabian and Hokmabadi [21]stimulated faulting and wave propagation in the laboratoryof Isfahan Technological University Iran and adoptedequivalent boundary conditions put forward by Takadawhen it came to boundary conditions related to the end ofthe pipe so they conducted a parametric study on the be-haviour of buried pipelines

Equivalent boundary

Axial spring damper

Equivalent boundary

Lateral spring damper

Vertical spring damper

Figure 15 Apparent propagation of an R wave strain of the ground and curvature results

Shock and Vibration 7

Rofooei and Qorbani [19] assumed a vertical wavepropagation in order to conduct a parametric study oncontinuous pipes under earthquake loadingey stimulatedthe pipe and surrounding soil through springs according tothe ALA regulation using ANSIS software Considering datacollected from effects of pipe and soil geometric changes ontheir relative displacement they observed increase in relo-cation in the soil-pipe boundary due to decrease in soilaggregation

35 e Seismic Susceptibility Model concerning BuriedPipelines Hazussr2i is a guideline on estimating damage tostructures due to the earthquake which was developed byFEMA and the national institute of the US Architecture It iscomprised of ways to estimate the extent of earthquakedamage to various structures including lifelines Accord-ingly the guideline suggests that leakage tends to happenbecause of earthquake waves in which 80 depends uponmaximum earth velocity and 20 is a function of earthrsquospermanent transformations while it has been found thatpipe breakage proves to be due to earthrsquos big transformationsin which 20 and 80 depend upon PGA and PGDrespectively

Furthermore the method divides pipes into two groupsincluding frangible and flexible As a result susceptibility offlexible pipes decreases by 70 e likelihood of soil liq-uefaction has been directly entered to the Hazus modelwhich is assumed as the most significant factor on pipedisplacement e algorithm concerning susceptibility ofburied pipes under earthquake waves was found by ana-lysing experimental data collected from four earthquakes inthe US and two in Mexico en data were adjusted to theHazus method

e guideline divides pipes into small and big groups inorder to estimate time required for reconstructing pipelinesdamaged in earthquakes Accordingly the small group in-cludes pipes having a diameter of 20 inch or less while othersare put in the big group e method also estimates daysrequired for reconstruction of the water supply system efollowing assumptions suggest how to measure days forrepair the pipeline It takes an equipped four-man team forfour and eight hours to repair a leaky and a broken piperespectively It takes an equipped four-man team for six and

twelve hours to repair a leaky and a broken pipe respec-tively ere is a linear link between repair program andtime As a result the extent of repairs done on a pipelinewhich needs (a) days within (b) days with a fixed number ofworkers is measured ba (Table 2)

36eSusceptibility IndexVI In this method the weightedcoefficient is assumed as a factor covering pipe diameter cdconditions of the ground cg magnitude of the earthquakebased on the Mercalli intensity scale ci pipe passage throughthe fault cf soil liquefaction c1 and potential land slideoccurrence potential Tables 3ndash10 give information aboutweighted coefficients Susceptibility of each part in thewastewater system is achieved by giving weight to above-mentioned factors in different conditions and then multi-plying the value by the weighted coefficient of each factorConsidering data from Table 10 and based on values ob-tained from forgoing equation (6) susceptibility of thewastewater system is divided into three groups includinghigh medium and low It is worth mentioning thatweighted coefficients concerning each factor have been se-lected based on maximum recorded damage to the buriedpipeline in past earthquakes Table 5 gives information aboutweighted coefficient regarding conditions of the groundbased on different types of soil In addition Table 6 illus-trates magnitude of an earthquake as well as correspondentimproved intensity scale (MMI) in PGA

VI cd middot cp middot cf middot cg middot ci middot cl middot cs (6)

4 Numerical Simulation

A complete set is comprised of software hardware datamodels algorithms and human resources for collectingpreparing organizing storing updating processing andanalysing different types of local data Such a system aims tomanage and handle information collected from the referenceplace in order to make sensible decisions e data modelindicates transformation of the real world by observingrelated geometrical relations and descriptive information toa reasonable and digital oneemodel represents all objectsin the form of points lines or polygon However topologicaldata aim to extract relations between phenomena Existing

Base springs

Longitudinal soil springs not shown

Overburden or uplift springs

Initial position

Design thawsettlement

Figure 16 Finite-element model of a shell element in collision with the fault

8 Shock and Vibration

relations between phenomena in local data function as partand particle of some GIS analysing systems In the rastermodel the whole map is divided into a set of small andregular cells called pixel e raster format is actuallycomposed of an nlowastm array of pixels

e geographical information system (GIS) has recentlyattracted the attention of different engineering fields e

ability to interpret and analyse data in such systems andsoftware enables us to review multiple parameters andfactors affecting different analyses and achieve reliable re-sults Research has proved the applicability of GIS to analysedata and extract results in the field of water and wastewaterengineering In the current research the most well-knownsoftware package appertain to geographical informationArcGIS Desktop 101 has been used to analyse data For thepurpose of analysis first softwarersquos default data and geo-graphical tiers called GIS READY were prepared eprocess was comprised of improving designing mistakes andthen doing a georeferencing operation

Since most of data were in the form of paper maps theywere first scanned and then by taking the scale of data intoaccount data were turned into a numerical one Finally withregard to available data as well as type of analysis all datawere changed into a roster model based on their effectiveparameters (Figure 17)

Table 2 Hazus equations concerning the ratio of damage to a buried pipeline

Type of pipe e ratio of damage to a PGV pipe per kilometer e ratio of damage to a PGD pipe per kilometerFragile RR 00001lowastPGV225 RR prob lowastPGD056Flexible RR 03 lowast 00001 lowastPGV225 RR 03 lowast prob lowastPGD056PR is defined as the extent of damage to the pipe per kilometerPGV (cmsminus1)PGD (inch)

Table 3 Weighted coefficient for diameter of a pipe

Coefficient cd Pipe diameter (d)Dlt 75mm 1675mmlt dlt 150mm 10150mmlt dlt 250mm 09250mmlt dlt 450mm 07450mmlt dlt 1000mm 05dgt 1000mm 04

Table 4 Weighted coefficient for type of pipe

Type of the pipeline Coefficient (cp)Soft cast iron 03Cast iron 10Ceramic 3Asbestos 25Poly ethylene 01Concrete 2

Table 5 Weighted coefficient for conditions of the ground

Type of soil CoefficientType I 05Type II 1Type III 2Type IV 29

Table 6 Weighted coefficient for magnitude of the earthquake

Magnitude of the earthquake CoefficientMMIlt 8 10PGAlt 025G8ltMMIlt 9 21025GltPGAlt 045G9ltMMIlt 10 24045GltPGAlt 06G10ltMMIlt 11 3006GltPGAlt 09G11ltMMI 35PGAgt 09G

Table 7 Weighted coefficient for passage of the pipeline throughthe fault

Passage of the pipeline through a fault CoefficientNo passage 1One passage 2Multiple passages 24

Table 8 Weighted coefficient for soil liquefaction

Liquefaction Coefficient0ltPL1lt 5 15ltPLlt 15 2PLgt 15 24

Table 9 Weighted coefficient for the land slide potential CS

Potential of the land slide CoefficientNo danger 1Medium danger 2High danger 24

Table 10 Classification of the extent of seismic susceptibility of thewastewater system

Color Susceptibility level VI indexGreen Low 0ltVIlt 5Orange Medium 5ltVIlt 12Red High VIgt 12

Shock and Vibration 9

41 Statistical Population Gorgan a city in Golestan Iranwas selected in the current case study research It has beenthe first city in the province equipped with the wastewatersystem As the city experiences dozens of small earthquakesevery day it is worth studying susceptibility of the waste-water system to earthquake e wastewater system is124meters in length (Figure 18)

First maps developed in AutoCAD software pertinent tothe Gorgan wastewater system were collected in order toassess the extent of damage to the system due to earthquakesNext maps were turned into GIS data Both 2 and 10 percentdanger analysis maps were adjusted to aerial photos andthen corrected ones were entered into GIS software tomeasure the seismic susceptibility ratio under maximumland movement

42 Sampling Method and Sample Size In the current re-search two types of data including maps of seismic analysisand wastewater pipelinesrsquo code were used e former in-cludes curves aligned with velocity of potential approachesof the vertical element which are pertinent to a return periodof 75 years for 2 PGA and a return period of 475 years for10 PGA for an estimated 50 year service life

43 e Map of Selected Wastewater System e Gorganwater and wastewater organization has provided the re-searcher with given maps as well as a file containing pipe-linesrsquo codes (Figures 19 and 20) en the file entered intothe GIS software and improved

44 Data Analysis Research variables include characteris-tics of pipes as well as velocity of the earthquake which havebeen drawn by adjusting rough maps of earthquake velocityand the cityrsquos wastewater system (Figures 21 and 22)

5 Results and Discussion

Raw data were put into GIS software as input and twooutput data were obtained Figures 23 and 24 illustrate the

Iteratefeature

Select layerby location

Summarystatistics

Get fieldvalue

Calculatefield End

Figure 17 e algorithm determining the extent of damage observed under an earthquake wave in GIS

Figure 18 Geographical location of Gorgan

Figure 19 e organization map of the urban wastewater system

Diameter150200250300400500600700800

Figure 20 e map of Borujen wastewater system (diameter ofpipes)

033

031

Figure 21 e PGA10 map and Borujenrsquos wastewater system

10 Shock and Vibration

extent of damage to pipes using Hazus based on two dif-ferent earthquake velocities namely PGA 2 and PGA 10

Figures 25 and 26 give information about the extent ofdamage under two different earthquakes according to the VImethod

6 Conclusion

Comparing HAUS and VI methods suggests that the formergives more accurate and detailed data so it enables au-thorities to make better decisions for boosting and planningstructures and finding their susceptible points Moreover asthe method helps to find out the extent of damage structureswould suffer after occurrence of an earthquake recon-struction process would be done quickly and precisely

Considering the point that the region has always beenearthquake-prone reviewing data obtained frommaps showa high level of damage Maps are indicating the first pre-diction of the current research that is to say susceptibility ofthe wastewater system to occurrence of any earthquake so itfocuses on the necessity for replacing existent pipelines withmore resistant ones

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

049

052

Figure 22 e PGA2 map and wastewater system

0867840466ndash37318188373181886ndash6595797256595797252ndash94597756

9459775645ndash12323754

1232375405ndash151877321518773244ndash180517101805171083ndash20915689

2091568922ndash237796672377966762ndash26643646

Number of repair10

Figure 23 e total number of Hazus SR2 damage underPGA10

494688108017143028310733633443371853167709116841346914669157521636517644

Number of repair2value

Figure 24 e total number of Hazus SR2 damage under PGA2

Figure 25 e total number of damage under PGA2 accordingto the VI method

Figure 26 e total number of damage under PGA10 accordingto the VI method

Shock and Vibration 11

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T D OrsquoRourke and S S Jeon ldquoFactors affecting the earth-quake damage of water distribution systems in optimizingpost-earthquake lifeline system in optimizing post-life linesystem reliabilityrdquo in Proceedings of the Fifth US Conferenceon Lifeline Earthquake Engineering ASCE Seattle WC USA1999

[2] U Albayrak A Loai and M Morshid ldquoEvaluation of seismicperformance of steel lattice transmission towersrdquo Civil En-gineering Journal vol 6 no 10 pp 1ndash21 2020

[3] B Cai and M H Golestan ldquoTowards bayesian quantificationof permeability in micro-scale porous structuresrdquo e Da-tabase of Micro Networks vol 1 no 4 pp 1ndash13 2020

[4] H Shah and S Chu ldquoSeismic analysis of undergroundstructural elementsrdquo Journal of the Power Division vol 100no 1 pp 53ndash62 1974

[5] E C Goodling ldquoBuried pipingndashan analysis procedure up-daterdquo in Proceedings of the International Symposium onLifeline Earthquake Engineering vol 77 pp 225ndash237 ASMEPortland Oregon May 1983

[6] M Shinozuka and T Koike ldquoEstimation of structural strain inunderground lifeline pipesrdquo Lifeline Earthquake Engineering-Buried Pipeline Seismic Risk and Instrumentation vol 34pp 31ndash48 1979

[7] S Takada and K Tanabe ldquoree-dimensional seismic re-sponse analysis of buried continuous or jointed pipelinesrdquoJournal of Pressure Vessel Technology vol 109 no 1pp 80ndash87 1987

[8] S Takada A Carlo S Bo and X Wuhu Current State of theArts on Pipeline Earthquake Engineering in Japan eConstruction Engineering Research Foundation PuneMaharashtra India vol 1 1992

[9] L Dai D Wang T Wang Q Feng and X Yang ldquoAnalysisand comparison of long-distance pipeline failuresrdquo Journal ofPetroleum Engineering vol 2017 no 1 7 pages Article ID3174636 2017

[10] Y Yang S Yang Z Li et al ldquoAnalysis of hazard area ofdispersion caused by leakage from underground gas-storagecaverns in salt rockrdquo Advances in Civil Engineering vol 2020no 1 11 pages

[11] M Cubrinovski Geotechnical Reconnaissance of the 2010Darfield (New Zealand) Earthquake University of Canter-bury Christchurch New Zealand 2010

[12] Y Maruyama and F Yamazaki ldquoConstruction of fragilitycurve for water distribution pipes based on damage datasetsfrom recent earthquakes in Japanrdquo in Proceedings of the 9thUS National and 10th Canadian Conference on EarthquakeEngineering Toronto ON Canada July 2010

[13] J F Bird and J J Bommer ldquoEarthquake losses due to groundfailurerdquo Engineering Geology vol 75 no 2 pp 147ndash179 2004

[14] M Zare and S Wilkinson ldquoEarthquake damage in wastewatersystem and post earthquake repair methodslimitation andpractcerdquo in Proceedings of the Australian Earthquake Engi-neering Society Conference Novotel Bavossa Valley RwsortBarossa Valley South Australia November 2011

[15] R T Eguchi ldquoSeismic vulnerability models for undergroundpipesrdquo in Proceedings of the International Symposium onEarthquakeBehavior and Safety of Oil and Gas Storage

Facilities Buried Pipelines and Equipment American Societyof Mechanical Engineers (ASME) New York NY USAJanuary 1983

[16] N M Newmark ldquoSeismic design criteria for structures andfacilities Trans-Alaska pipeline systemrdquo in Proceedings of theUS National Conference on Earthquake Engineering Earth-quake Engineering Institute San Francisco CA USA June1975

[17] G Yeh ldquoSeismic analysis of slender buried beamsrdquo eBulletin of the Seismological Society of America vol 64o no 5pp 1551ndash1562 1974

[18] S Takada N Hassani and K Fukuda ldquoA new proposal forsimplified design of buried steel pipes crossing active faultsrdquoEarthquake Engineering amp Structural Dynamics vol 30 no 8pp 1243ndash1257 2001

[19] F R Rofooei and R Qorbani ldquoA parametric study on seismicbehavior of continuous buried pipeline due to wave propa-gationrdquo in Proceedings of the 14th World Conference onEarthquake Engineering Beijing China October 2008

[20] M Hosseini and S Jallili ldquoAssessment of the nonlineearbehavior of connection in water distribution networks fortheir seimic evaluationrdquo Procedia Engineering vol 14pp 2878ndash2883 2011

[21] A M Halabian and T Hokmabadi ldquoA new hybrid model forrigorous analysis of buried pipelines under general faultingaccounting for material and geometrical non-linearities withfocusing on corrugated HDPE pipelinesrdquo Soil Dynamics andEarthquake Engineering vol 115 pp 1ndash17 2018

12 Shock and Vibration

between inlet and outlet tangents Moreover relocationarising from slipping (Δ) measured by subtracting the re-location of a piece of pipe (pΔ) from relocation of soil (sΔ)Although the previous method assumed bending rigid theretends to be some transformations in sags creating tendencyto decrease in flexural moment

Goodling [5] put forward equations based on analysingbending in thin-walled curved pipes In a research study [6]suggested a method for predicting relocation of the sag inwhich the Riley wave was assumed as a transmittal sine wavewith limited wave length In the same token relocation of thepipe was assumed equal to that of ground where displace-ment of ground was zero and they developed a simpleequation for pipe strain in the point of sags based on cor-respondent structural analyses ey assumed effectivelength (Lprime) one-fourth of the wave length so anchors couldbe measured by virtue of displacement compatibilityequations in the curve

Takada and Tanabe [7] put forward knee and T-joints aremore susceptible to damage than other parts of a pipelineand maximum tensile pressure can affect them In 2003OrsquoRourke and McLaughlin developed a two-dimensionalfinite-element model as their PhD dissertation ey entereda quasistatic sine Riley wave into the numerical model andcompared results obtained from a steel pipe having a di-ameter and thickness of 24 and 5 inch in a sand soil with areduction factor (06) with that of obtained by Shah and Chu[4] as well as [6] for a flat surface steel

Moreover OrsquoRourke and Jeon [1] utilized a finite-ele-ment model developed in Nastran software to stimulate theproblem and comparing analytical resultsey assumed thepipe as a column element for modelling and each bendinghad a length of 125meters equal to one-fourth of a wavelength having 500meters To verify this model data collectedfrom the analytical method were compared with that of thefinite-element model So it was found that results obtainedfrom the analytical method were almost better in all cases Ascan be seen from prior works most of numerical analysesconcerning were quasistatic however studies on dynamicbehaviour of pipe under earthquake loading are still lacking

In 2008 F R Rofooei and R Qorbani did a research oncontinuous pipes assuming vertical wave propagation andthen compared obtained strain results with that of observedin a pipe having a knee-joint Results showed that the ex-istent sag led to an increase in strain and pressure in theknee-joint than a continuous pipe Moreover Takada et al[8] did a numerical research on a set of pipes combining Tand knee-joint and showed that the seismic behaviour of apipe network was more than a continuous one In additionadjacent pipes showed inconsiderable increased behaviourthan patchy ones

Dai et al [9] studied about analysis and comparison oflong-distance pipeline failures and they found that accordingto the statistical results PNGPC is not very far compared withforeign countries ere are still some aspects both in tech-nology and in management that should be improved such asquality of manufacture and construction of pipeline andthird-party monitoring Also Yang et al [10] did researchabout numerical simulation of pipeline-pavement damage

caused by explosion of leakage gas in buried pipelines andshowed that the results can provide theoretical basis formunicipal pipeline construction design and urban safetyplanning and provide references for the risk assessment of gasexplosion in buried pipelines

21 New Zealand Earthquake Christchurch is New Zea-landrsquos second biggest city Its sewage system covers almost150000 families Although the system is made up of con-crete ceramic UPVC and asbestos pipes it has a highpercentage of concrete one An earthquake measuring 71 onthe Richter scale hit the city on 4th September 2010 (Fig-ure 3) e sewage system was badly destroyed Demolitionrate of pipes made up of concrete and reinforced concrete(09) increases the likelihood of corrosion [11]

22 JapanEarthquakes An earthquakemeasuring 68 on theRichter scale called Nigata-Ken Chuetsu hit the city inOctober 2004 Destruction of the sewage-treatment plant ledto flow of raw sewage into the city to such an extent that151 kilometer sewage pipeline was destroyed and 2056manholes were also damaged e greatest damage recordedfor tucking water behindmanholes and pipes which not onlygenerated heavy traffic but also caused failure to pumphousesrsquo sewage Another earthquake measuring 75 on theRichter scale hit Nigata Japan on 16th January 1964 Over470 km pipeline namely 68 of pipes is damagedemostdestruction was recorded for cast iron pipes and jointsAccording to data other pipes especially those with smalldiameter showed more damage due to bending Many pipesand installation became visible on the ground because of soilliquefaction In addition slope of the soil is also consideredas an important factor in damages [12]

23 Manjil Earthquake Iran (1990) An earthquake hitRodbar and Manjil Iran on 21st July 1990 It caused severedamage to several buildings roads installation and even theSefidrood concrete dam [13] ere are still insufficient datafor the extent of damage to the water supply system Al-though buildingsrsquo water pipes had been badly damagedmain pipelines of the city water supply system were in asatisfactory condition thanks to putting new pipes in depth(Figure 4)

24 Bam Earthquake (2003) An earthquake measuring 68on the Richter scale struck Bam Iran on 26 December 2003e city had a total population of 12000 According to re-ports asbestos fittings of pipes had been damaged but themain water supply system was slightly damaged [14] Al-though water gushed from broken domestic pipes watertanks were not badly damaged mainly because they wereunderground (Figure 5)

3 Material and Methods

31 Effective Factors Causing Damage to Pipelines after Oc-currence of anEarthquake Multiple parameters have impact

Shock and Vibration 3

on damage to underground pipelines after occurring anearthquake In general characteristics of a pipeline soiland magnitude of an earthquake affect the seismic be-haviour of the pipeline As such there are considerablefactors having effect on the seismic behaviour of buriedpipelines In a research Eguchi et al studied factors af-fecting susceptibility of buried pipelines when an earth-quake happens through analysing damage to the buildingsdestroyed in the San Francisco earthquake [15] Evidencesuggested that the devastating effect of faulting was muchmore than distortion due to earthquake movements As aresult the closer a building is to the fault the worse it wouldbe destroyed A pipeline would be inevitably face to moredangers due to its extent than other installations whichcover a small area simply because long pipelines are spreadover regions having active faults or soil liquefaction eterm faulting is meant fracture of faults which is happenedon the ground ere are three main types of faultingincluding horizontal vertical or a combination of themInstallations located on the fault line are much moresusceptible to the earthquake (Figure 6)

Figure 6 shows an ideal structural model on a fault lineand the probability and extent of soil liquefaction will in-crease by increase in the continuance in earthquake Soilliquefaction as well as lateral movements is viewed asdevastating parameters which may lead to bury surfacestructures under soil or help underground structures tobecome visible Shaking cause to compress soil and sub-sidence is occurred However the extent of persistent

Figure 4 Damage occurred from Manjil earthquake

Figure 5 Damage occurred from Bam earthquake

Fault trace

500 m 500 m

Y

A

X

B C C

D

E EOβ

δf

Figure 6 Ideal structural model during faulting

0

02

04

06

08

1

AC CI CLS CONC EW HDPE MPVC PVC RCRR UPVC

Damage rate

Figure 3 Demolition rate of pipelines considering their type in the New Zealand earthquake

4 Shock and Vibration

relocation due to subsidence is less than that of due to soilliquefaction Notwithstanding subsidence is of importancebecause of making heterogeneous dislocations in soil

32 Features of the Pipeline Affecting Susceptibility of theBuried Pipelines due to an Earthquake Most of parametersaffecting susceptibility of buried pipelines due to anearthquake have much to do with characteristics of thepipeline Prior studies showed that type of the pipe plays apivotal role To put it simply its flexibility helps the pipingsystem because it leads to easily movement of soil along withthe pipe which prevent the pipe from bursting during anearthquake Increase in the internal diameter of pipelinesdecreases both bending and axial tensions due to affectingsoil-pipe interaction Final conditions have marginal effecton tensions created in cross sections when it comes to lengthof pipe With regard to data collected from the analysis it ishighly likely that the pipe will rupture at its junction withother installations such as manholes and storages thanother sections of the pipeline (Figure 7ndash9)

e pipeline bears lateral loads during an earthquakewhich it oscillates pipes and cuts their connections with thesaddle However bracing spaces helps the system not to bedevastated Figure 10 illustrates demolition of pipesrsquo supportdue to soil liquefaction in the Northbridge earthquake(1994)

However seismic and flexible joints have been found tosuggest great function during an earthquake which it leads todecrease in demolition of the water supply system On theother hand accruing to data collected from prior researchcontinuous pipes such as the ones made up of steel withwelded joints have shown greater function than sectionalpipes with lots of joints In addition the extent of demolitionobserved for asbestos pipes in Loma Prieta (1989) andNorthridge (1994) earthquakes was less than that recordedfor Mexico City earthquake (1985)

Researchers also argue that connection behaviour wouldprove to be linear when pipesrsquo relative rotation is 005 radianMoreover bending experiments on fittings used in flexiblecast iron pipes having rubber-made washers and differentdiameters showed that rotation of joints is done around thepipe Improper hardness distribution is the leading cause ofmost of the destructions of the water supply system As aresult relocations arising from such shakes are different andcause to break joints between pipes (Figures 11 and 12)

33 Methods of Studying the Seismic Behaviour of a PipelineWith regard to the destructions left after earthquakes re-searchers set the stage to conduct a comprehensive study inorder to develop some methods to find how seismic be-haviour affects the pipelines e methods are generallydivided into three groups including approximate analysis[16] accurate analysis and building code methods Shakesarising from an earthquake go through many changes due toseveral reasons before happening which will affect structuresin different ways Initial works in the field of buried pipelinesfocused preliminary on the main factor that is to say thepath through which waves move In addition as can be seen

from numerical calculations its effect has been considered inthe form of a semistatic factor

Regarding dynamic analyses done on buried pipelinesespecially on their bending points the impact of this factorhas omitted and pipes were only analysed by taking verticaldistribution and synchronous shakes throughout all pointsinto account Wave propagation velocity functions as aleading parameter to calculate strain Shear wave velocitywas used to calculate the extent of axial strain in areas having

0

500

1000

1500

2000

2500

3000

0 50 100 150 200

Bend

ing

tens

ion

Length (m)

Figure 7 Variation in the extent of maximum bending tensionsalong the pipeline with different final conditions

0

1000

2000

3000

4000

5000

0 50 100 150 200 250 300

Bend

ing

tens

ion

Length (m)

Figure 8 Variation in the extent of maximum axial tensions alongthe pipeline with different final conditions

0

1000

2000

3000

4000

5000

0 50 100 150 200

Bend

ing

tens

ion

Length (m)

Figure 9 Variation in the extent of maximum axial tensions alongthe pipeline with different final conditions

Shock and Vibration 5

focal length less than five times of the distance from focaldepth to the epicentre of an earthquake while Riley wavevelocity was utilized to calculate distances more than givenamount In a research study OrsquoRourke et al studied hori-zontal apparent speed for body waves ey developed ananalytical method to assess the shear wave angle of incidentSo apparent speed for shear waves is calculated as

Cs - apparent cs

sin θ (1)

where θ is the incident angle of the shear wave to thehorizontal and Cs is the velocity of shear waves in surfacesoil Phase velocity of the wave is the same apparent velocityUnlike body waves phase velocity depends upon frequencyWith regard to the Riley wave there is relation among wavelength (λ) frequency and phase velocity Figure 13ndash15 il-lustrate a scheme of Riley wave propagation with an ap-parent velocity

Wave propagation has been found to put strain on theground Measuring strain of ground is done by studyingsimple transitional movement of a wave having fixed shapeIt was assumed that velocity and movement of two pointsthroughout a propagation path simply differ in a time lag inwhich in turn it is a function of the distance between twopoints and the seismic wave velocity In the same tokenmaximum tensile or compressive strain of the earth (gє) inthe direction of wave propagation is measured as

εg VmC

(2)

where Vm is themaximum horizontal velocity of the earth inthe direction of wave propagation and C is the apparentpropagation velocity of the seismic wave To propagate aRiley wave strain parallel with the ground could be mea-sured using the equation above where C is replaced by thevalue of phase velocity according to the wave lengthequivalent to four times of the separation distance (thelength of the pipe located between two bridles which is aboutto analyse) e equation needs to be changed when thegiven direction is parallel to the line of wave propagationGenerally as can be seen from the figure below the wave hasangle in both vertical and horizontal plates So the equation

Figure 10 Demolition of pipesrsquo support due to soil liquefaction inthe Northbridge earthquake (1994)

Figure 11 Cracks observed in the joint between a restrained weakpipe and an unrestrained one [11]

Figure 12 Cracks in the pipe connected to the storage (ALA 2002)

P wave

S wave

Low wave

Rayleigh wave

Compression

Tension

Figure 13 Comparing R and S waves in designing pipes

Apparent velocity vax

True velocity V

Mrsquo Mrsquorsquo

M

θ

θ

z

x

Figure 14 Apparent propagation of a shear wave

6 Shock and Vibration

below is used to measure apparent wave velocity in thedirection of pipersquos axis

Cs - apparent cs

sin θ middot cos c (3)

Yeh [17] illustrated that maximum strain of the earth ismeasured by 45 θ c in given plates

34 Studying Seismic Behaviour of a Soil-Pipe System con-cerning Continuous Buried Pipelines A structure bearsbending or axial transformations after an earthquakeProviding satisfying plasticity in order to absorb transfor-mations due to earthquake without decrease in static loadingcapacity acts as an important design criterion Generallydeveloped axial strain throughout a continuous direct pipedepends upon such factors as shape of the earth transmittalwave length and soil-pipe interaction forces Althoughstrain of pipe and soil are assumed equal for small- tomedium-sized movements the same is not true for greatstrains because of existent slipping between soil and pipe Ithas been found to decrease pipe strain compared to that ofsoil Newmark [16] put forward a simple method to de-termine how the pipeline acts when earthquake waves arepropagated en other researchers such as Yeh revised it

Seismic movement of the earth which is defined as thehistory of velocity-time and velocity-displacement func-tions as a transmittal wave with fixed shape It suggests thattwo points along the propagation path simply shake by atime lag Inertia involved in small movement equations istoo small to be measured Later the assumption was studiedby many researchers and their works showed that it acts as areasonable engineering approximation It is assumed that norelative movement happens in the soil-pipe interaction andpipersquos strain equals to that of soil In addition OrsquoRourke andEl Hamadi developed an analytical method to estimatemaximum pipe strain

e method assumes that first axial strain in soil equalspipe strain arising from length friction between soil and pipeand second waves are propagated parallel to the axis of pipeIn a research study OrsquoRourke and Jeon [1] compared data

collected from three mentioned analytical methods when itcame to the continuous pipeline under the Riley waversquospropagation Besides the model put forward by Takada [18]suggested that pipe is modelled in the form of a shell having alength of 60 D adjacent to the fault but it could be in theform of an beam element where the distance from the pipe tothe fault is almost 300meters and the extent of soil and pipeslipping and strains are insignificant (Figure 16) All thingsbeing equal soil surrounded the pipe is modelled using soilsprings according to the seismic designing regulation ofburied oil and gas pipes [19]

In 2004 Takada et al reported on a newmodel accordingto changes in boundary conditions ey suggest that thepipe should be modelled in the junction with the fault in theform of a shell element due to local strain and big trans-formations just the same as before Moreover each point ofthe shell element is connected to three soil springs in axiallateral and vertical directions Finally the relation betweenthe axial force (f ) and increased length ΔL which is regardedto boundary conditions for nonelastic springs is measuredas

F(ΔL)

3EAfs2

1113970U016ΔL

23 0ltΔLltU0 (4)

3EAfsΔL minus 14U0

1113874 1113875

1113970σy2A2Efs

+U04

(5)

where Yσ acts as pipersquos yield stress and elasticity modulus Ithas been suggested that tensile rupture local buckling andthimble buckling are among the most significant damage tocontinuous pipes while tensile and compression ruptures ofpipe joints as well as local bending were the most commondamage observed in apart pipeline [20] Concerning mod-elling of continuous pipes Halabian and Hokmabadi [21]stimulated faulting and wave propagation in the laboratoryof Isfahan Technological University Iran and adoptedequivalent boundary conditions put forward by Takadawhen it came to boundary conditions related to the end ofthe pipe so they conducted a parametric study on the be-haviour of buried pipelines

Equivalent boundary

Axial spring damper

Equivalent boundary

Lateral spring damper

Vertical spring damper

Figure 15 Apparent propagation of an R wave strain of the ground and curvature results

Shock and Vibration 7

Rofooei and Qorbani [19] assumed a vertical wavepropagation in order to conduct a parametric study oncontinuous pipes under earthquake loadingey stimulatedthe pipe and surrounding soil through springs according tothe ALA regulation using ANSIS software Considering datacollected from effects of pipe and soil geometric changes ontheir relative displacement they observed increase in relo-cation in the soil-pipe boundary due to decrease in soilaggregation

35 e Seismic Susceptibility Model concerning BuriedPipelines Hazussr2i is a guideline on estimating damage tostructures due to the earthquake which was developed byFEMA and the national institute of the US Architecture It iscomprised of ways to estimate the extent of earthquakedamage to various structures including lifelines Accord-ingly the guideline suggests that leakage tends to happenbecause of earthquake waves in which 80 depends uponmaximum earth velocity and 20 is a function of earthrsquospermanent transformations while it has been found thatpipe breakage proves to be due to earthrsquos big transformationsin which 20 and 80 depend upon PGA and PGDrespectively

Furthermore the method divides pipes into two groupsincluding frangible and flexible As a result susceptibility offlexible pipes decreases by 70 e likelihood of soil liq-uefaction has been directly entered to the Hazus modelwhich is assumed as the most significant factor on pipedisplacement e algorithm concerning susceptibility ofburied pipes under earthquake waves was found by ana-lysing experimental data collected from four earthquakes inthe US and two in Mexico en data were adjusted to theHazus method

e guideline divides pipes into small and big groups inorder to estimate time required for reconstructing pipelinesdamaged in earthquakes Accordingly the small group in-cludes pipes having a diameter of 20 inch or less while othersare put in the big group e method also estimates daysrequired for reconstruction of the water supply system efollowing assumptions suggest how to measure days forrepair the pipeline It takes an equipped four-man team forfour and eight hours to repair a leaky and a broken piperespectively It takes an equipped four-man team for six and

twelve hours to repair a leaky and a broken pipe respec-tively ere is a linear link between repair program andtime As a result the extent of repairs done on a pipelinewhich needs (a) days within (b) days with a fixed number ofworkers is measured ba (Table 2)

36eSusceptibility IndexVI In this method the weightedcoefficient is assumed as a factor covering pipe diameter cdconditions of the ground cg magnitude of the earthquakebased on the Mercalli intensity scale ci pipe passage throughthe fault cf soil liquefaction c1 and potential land slideoccurrence potential Tables 3ndash10 give information aboutweighted coefficients Susceptibility of each part in thewastewater system is achieved by giving weight to above-mentioned factors in different conditions and then multi-plying the value by the weighted coefficient of each factorConsidering data from Table 10 and based on values ob-tained from forgoing equation (6) susceptibility of thewastewater system is divided into three groups includinghigh medium and low It is worth mentioning thatweighted coefficients concerning each factor have been se-lected based on maximum recorded damage to the buriedpipeline in past earthquakes Table 5 gives information aboutweighted coefficient regarding conditions of the groundbased on different types of soil In addition Table 6 illus-trates magnitude of an earthquake as well as correspondentimproved intensity scale (MMI) in PGA

VI cd middot cp middot cf middot cg middot ci middot cl middot cs (6)

4 Numerical Simulation

A complete set is comprised of software hardware datamodels algorithms and human resources for collectingpreparing organizing storing updating processing andanalysing different types of local data Such a system aims tomanage and handle information collected from the referenceplace in order to make sensible decisions e data modelindicates transformation of the real world by observingrelated geometrical relations and descriptive information toa reasonable and digital oneemodel represents all objectsin the form of points lines or polygon However topologicaldata aim to extract relations between phenomena Existing

Base springs

Longitudinal soil springs not shown

Overburden or uplift springs

Initial position

Design thawsettlement

Figure 16 Finite-element model of a shell element in collision with the fault

8 Shock and Vibration

relations between phenomena in local data function as partand particle of some GIS analysing systems In the rastermodel the whole map is divided into a set of small andregular cells called pixel e raster format is actuallycomposed of an nlowastm array of pixels

e geographical information system (GIS) has recentlyattracted the attention of different engineering fields e

ability to interpret and analyse data in such systems andsoftware enables us to review multiple parameters andfactors affecting different analyses and achieve reliable re-sults Research has proved the applicability of GIS to analysedata and extract results in the field of water and wastewaterengineering In the current research the most well-knownsoftware package appertain to geographical informationArcGIS Desktop 101 has been used to analyse data For thepurpose of analysis first softwarersquos default data and geo-graphical tiers called GIS READY were prepared eprocess was comprised of improving designing mistakes andthen doing a georeferencing operation

Since most of data were in the form of paper maps theywere first scanned and then by taking the scale of data intoaccount data were turned into a numerical one Finally withregard to available data as well as type of analysis all datawere changed into a roster model based on their effectiveparameters (Figure 17)

Table 2 Hazus equations concerning the ratio of damage to a buried pipeline

Type of pipe e ratio of damage to a PGV pipe per kilometer e ratio of damage to a PGD pipe per kilometerFragile RR 00001lowastPGV225 RR prob lowastPGD056Flexible RR 03 lowast 00001 lowastPGV225 RR 03 lowast prob lowastPGD056PR is defined as the extent of damage to the pipe per kilometerPGV (cmsminus1)PGD (inch)

Table 3 Weighted coefficient for diameter of a pipe

Coefficient cd Pipe diameter (d)Dlt 75mm 1675mmlt dlt 150mm 10150mmlt dlt 250mm 09250mmlt dlt 450mm 07450mmlt dlt 1000mm 05dgt 1000mm 04

Table 4 Weighted coefficient for type of pipe

Type of the pipeline Coefficient (cp)Soft cast iron 03Cast iron 10Ceramic 3Asbestos 25Poly ethylene 01Concrete 2

Table 5 Weighted coefficient for conditions of the ground

Type of soil CoefficientType I 05Type II 1Type III 2Type IV 29

Table 6 Weighted coefficient for magnitude of the earthquake

Magnitude of the earthquake CoefficientMMIlt 8 10PGAlt 025G8ltMMIlt 9 21025GltPGAlt 045G9ltMMIlt 10 24045GltPGAlt 06G10ltMMIlt 11 3006GltPGAlt 09G11ltMMI 35PGAgt 09G

Table 7 Weighted coefficient for passage of the pipeline throughthe fault

Passage of the pipeline through a fault CoefficientNo passage 1One passage 2Multiple passages 24

Table 8 Weighted coefficient for soil liquefaction

Liquefaction Coefficient0ltPL1lt 5 15ltPLlt 15 2PLgt 15 24

Table 9 Weighted coefficient for the land slide potential CS

Potential of the land slide CoefficientNo danger 1Medium danger 2High danger 24

Table 10 Classification of the extent of seismic susceptibility of thewastewater system

Color Susceptibility level VI indexGreen Low 0ltVIlt 5Orange Medium 5ltVIlt 12Red High VIgt 12

Shock and Vibration 9

41 Statistical Population Gorgan a city in Golestan Iranwas selected in the current case study research It has beenthe first city in the province equipped with the wastewatersystem As the city experiences dozens of small earthquakesevery day it is worth studying susceptibility of the waste-water system to earthquake e wastewater system is124meters in length (Figure 18)

First maps developed in AutoCAD software pertinent tothe Gorgan wastewater system were collected in order toassess the extent of damage to the system due to earthquakesNext maps were turned into GIS data Both 2 and 10 percentdanger analysis maps were adjusted to aerial photos andthen corrected ones were entered into GIS software tomeasure the seismic susceptibility ratio under maximumland movement

42 Sampling Method and Sample Size In the current re-search two types of data including maps of seismic analysisand wastewater pipelinesrsquo code were used e former in-cludes curves aligned with velocity of potential approachesof the vertical element which are pertinent to a return periodof 75 years for 2 PGA and a return period of 475 years for10 PGA for an estimated 50 year service life

43 e Map of Selected Wastewater System e Gorganwater and wastewater organization has provided the re-searcher with given maps as well as a file containing pipe-linesrsquo codes (Figures 19 and 20) en the file entered intothe GIS software and improved

44 Data Analysis Research variables include characteris-tics of pipes as well as velocity of the earthquake which havebeen drawn by adjusting rough maps of earthquake velocityand the cityrsquos wastewater system (Figures 21 and 22)

5 Results and Discussion

Raw data were put into GIS software as input and twooutput data were obtained Figures 23 and 24 illustrate the

Iteratefeature

Select layerby location

Summarystatistics

Get fieldvalue

Calculatefield End

Figure 17 e algorithm determining the extent of damage observed under an earthquake wave in GIS

Figure 18 Geographical location of Gorgan

Figure 19 e organization map of the urban wastewater system

Diameter150200250300400500600700800

Figure 20 e map of Borujen wastewater system (diameter ofpipes)

033

031

Figure 21 e PGA10 map and Borujenrsquos wastewater system

10 Shock and Vibration

extent of damage to pipes using Hazus based on two dif-ferent earthquake velocities namely PGA 2 and PGA 10

Figures 25 and 26 give information about the extent ofdamage under two different earthquakes according to the VImethod

6 Conclusion

Comparing HAUS and VI methods suggests that the formergives more accurate and detailed data so it enables au-thorities to make better decisions for boosting and planningstructures and finding their susceptible points Moreover asthe method helps to find out the extent of damage structureswould suffer after occurrence of an earthquake recon-struction process would be done quickly and precisely

Considering the point that the region has always beenearthquake-prone reviewing data obtained frommaps showa high level of damage Maps are indicating the first pre-diction of the current research that is to say susceptibility ofthe wastewater system to occurrence of any earthquake so itfocuses on the necessity for replacing existent pipelines withmore resistant ones

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

049

052

Figure 22 e PGA2 map and wastewater system

0867840466ndash37318188373181886ndash6595797256595797252ndash94597756

9459775645ndash12323754

1232375405ndash151877321518773244ndash180517101805171083ndash20915689

2091568922ndash237796672377966762ndash26643646

Number of repair10

Figure 23 e total number of Hazus SR2 damage underPGA10

494688108017143028310733633443371853167709116841346914669157521636517644

Number of repair2value

Figure 24 e total number of Hazus SR2 damage under PGA2

Figure 25 e total number of damage under PGA2 accordingto the VI method

Figure 26 e total number of damage under PGA10 accordingto the VI method

Shock and Vibration 11

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T D OrsquoRourke and S S Jeon ldquoFactors affecting the earth-quake damage of water distribution systems in optimizingpost-earthquake lifeline system in optimizing post-life linesystem reliabilityrdquo in Proceedings of the Fifth US Conferenceon Lifeline Earthquake Engineering ASCE Seattle WC USA1999

[2] U Albayrak A Loai and M Morshid ldquoEvaluation of seismicperformance of steel lattice transmission towersrdquo Civil En-gineering Journal vol 6 no 10 pp 1ndash21 2020

[3] B Cai and M H Golestan ldquoTowards bayesian quantificationof permeability in micro-scale porous structuresrdquo e Da-tabase of Micro Networks vol 1 no 4 pp 1ndash13 2020

[4] H Shah and S Chu ldquoSeismic analysis of undergroundstructural elementsrdquo Journal of the Power Division vol 100no 1 pp 53ndash62 1974

[5] E C Goodling ldquoBuried pipingndashan analysis procedure up-daterdquo in Proceedings of the International Symposium onLifeline Earthquake Engineering vol 77 pp 225ndash237 ASMEPortland Oregon May 1983

[6] M Shinozuka and T Koike ldquoEstimation of structural strain inunderground lifeline pipesrdquo Lifeline Earthquake Engineering-Buried Pipeline Seismic Risk and Instrumentation vol 34pp 31ndash48 1979

[7] S Takada and K Tanabe ldquoree-dimensional seismic re-sponse analysis of buried continuous or jointed pipelinesrdquoJournal of Pressure Vessel Technology vol 109 no 1pp 80ndash87 1987

[8] S Takada A Carlo S Bo and X Wuhu Current State of theArts on Pipeline Earthquake Engineering in Japan eConstruction Engineering Research Foundation PuneMaharashtra India vol 1 1992

[9] L Dai D Wang T Wang Q Feng and X Yang ldquoAnalysisand comparison of long-distance pipeline failuresrdquo Journal ofPetroleum Engineering vol 2017 no 1 7 pages Article ID3174636 2017

[10] Y Yang S Yang Z Li et al ldquoAnalysis of hazard area ofdispersion caused by leakage from underground gas-storagecaverns in salt rockrdquo Advances in Civil Engineering vol 2020no 1 11 pages

[11] M Cubrinovski Geotechnical Reconnaissance of the 2010Darfield (New Zealand) Earthquake University of Canter-bury Christchurch New Zealand 2010

[12] Y Maruyama and F Yamazaki ldquoConstruction of fragilitycurve for water distribution pipes based on damage datasetsfrom recent earthquakes in Japanrdquo in Proceedings of the 9thUS National and 10th Canadian Conference on EarthquakeEngineering Toronto ON Canada July 2010

[13] J F Bird and J J Bommer ldquoEarthquake losses due to groundfailurerdquo Engineering Geology vol 75 no 2 pp 147ndash179 2004

[14] M Zare and S Wilkinson ldquoEarthquake damage in wastewatersystem and post earthquake repair methodslimitation andpractcerdquo in Proceedings of the Australian Earthquake Engi-neering Society Conference Novotel Bavossa Valley RwsortBarossa Valley South Australia November 2011

[15] R T Eguchi ldquoSeismic vulnerability models for undergroundpipesrdquo in Proceedings of the International Symposium onEarthquakeBehavior and Safety of Oil and Gas Storage

Facilities Buried Pipelines and Equipment American Societyof Mechanical Engineers (ASME) New York NY USAJanuary 1983

[16] N M Newmark ldquoSeismic design criteria for structures andfacilities Trans-Alaska pipeline systemrdquo in Proceedings of theUS National Conference on Earthquake Engineering Earth-quake Engineering Institute San Francisco CA USA June1975

[17] G Yeh ldquoSeismic analysis of slender buried beamsrdquo eBulletin of the Seismological Society of America vol 64o no 5pp 1551ndash1562 1974

[18] S Takada N Hassani and K Fukuda ldquoA new proposal forsimplified design of buried steel pipes crossing active faultsrdquoEarthquake Engineering amp Structural Dynamics vol 30 no 8pp 1243ndash1257 2001

[19] F R Rofooei and R Qorbani ldquoA parametric study on seismicbehavior of continuous buried pipeline due to wave propa-gationrdquo in Proceedings of the 14th World Conference onEarthquake Engineering Beijing China October 2008

[20] M Hosseini and S Jallili ldquoAssessment of the nonlineearbehavior of connection in water distribution networks fortheir seimic evaluationrdquo Procedia Engineering vol 14pp 2878ndash2883 2011

[21] A M Halabian and T Hokmabadi ldquoA new hybrid model forrigorous analysis of buried pipelines under general faultingaccounting for material and geometrical non-linearities withfocusing on corrugated HDPE pipelinesrdquo Soil Dynamics andEarthquake Engineering vol 115 pp 1ndash17 2018

12 Shock and Vibration

on damage to underground pipelines after occurring anearthquake In general characteristics of a pipeline soiland magnitude of an earthquake affect the seismic be-haviour of the pipeline As such there are considerablefactors having effect on the seismic behaviour of buriedpipelines In a research Eguchi et al studied factors af-fecting susceptibility of buried pipelines when an earth-quake happens through analysing damage to the buildingsdestroyed in the San Francisco earthquake [15] Evidencesuggested that the devastating effect of faulting was muchmore than distortion due to earthquake movements As aresult the closer a building is to the fault the worse it wouldbe destroyed A pipeline would be inevitably face to moredangers due to its extent than other installations whichcover a small area simply because long pipelines are spreadover regions having active faults or soil liquefaction eterm faulting is meant fracture of faults which is happenedon the ground ere are three main types of faultingincluding horizontal vertical or a combination of themInstallations located on the fault line are much moresusceptible to the earthquake (Figure 6)

Figure 6 shows an ideal structural model on a fault lineand the probability and extent of soil liquefaction will in-crease by increase in the continuance in earthquake Soilliquefaction as well as lateral movements is viewed asdevastating parameters which may lead to bury surfacestructures under soil or help underground structures tobecome visible Shaking cause to compress soil and sub-sidence is occurred However the extent of persistent

Figure 4 Damage occurred from Manjil earthquake

Figure 5 Damage occurred from Bam earthquake

Fault trace

500 m 500 m

Y

A

X

B C C

D

E EOβ

δf

Figure 6 Ideal structural model during faulting

0

02

04

06

08

1

AC CI CLS CONC EW HDPE MPVC PVC RCRR UPVC

Damage rate

Figure 3 Demolition rate of pipelines considering their type in the New Zealand earthquake

4 Shock and Vibration

relocation due to subsidence is less than that of due to soilliquefaction Notwithstanding subsidence is of importancebecause of making heterogeneous dislocations in soil

32 Features of the Pipeline Affecting Susceptibility of theBuried Pipelines due to an Earthquake Most of parametersaffecting susceptibility of buried pipelines due to anearthquake have much to do with characteristics of thepipeline Prior studies showed that type of the pipe plays apivotal role To put it simply its flexibility helps the pipingsystem because it leads to easily movement of soil along withthe pipe which prevent the pipe from bursting during anearthquake Increase in the internal diameter of pipelinesdecreases both bending and axial tensions due to affectingsoil-pipe interaction Final conditions have marginal effecton tensions created in cross sections when it comes to lengthof pipe With regard to data collected from the analysis it ishighly likely that the pipe will rupture at its junction withother installations such as manholes and storages thanother sections of the pipeline (Figure 7ndash9)

e pipeline bears lateral loads during an earthquakewhich it oscillates pipes and cuts their connections with thesaddle However bracing spaces helps the system not to bedevastated Figure 10 illustrates demolition of pipesrsquo supportdue to soil liquefaction in the Northbridge earthquake(1994)

However seismic and flexible joints have been found tosuggest great function during an earthquake which it leads todecrease in demolition of the water supply system On theother hand accruing to data collected from prior researchcontinuous pipes such as the ones made up of steel withwelded joints have shown greater function than sectionalpipes with lots of joints In addition the extent of demolitionobserved for asbestos pipes in Loma Prieta (1989) andNorthridge (1994) earthquakes was less than that recordedfor Mexico City earthquake (1985)

Researchers also argue that connection behaviour wouldprove to be linear when pipesrsquo relative rotation is 005 radianMoreover bending experiments on fittings used in flexiblecast iron pipes having rubber-made washers and differentdiameters showed that rotation of joints is done around thepipe Improper hardness distribution is the leading cause ofmost of the destructions of the water supply system As aresult relocations arising from such shakes are different andcause to break joints between pipes (Figures 11 and 12)

33 Methods of Studying the Seismic Behaviour of a PipelineWith regard to the destructions left after earthquakes re-searchers set the stage to conduct a comprehensive study inorder to develop some methods to find how seismic be-haviour affects the pipelines e methods are generallydivided into three groups including approximate analysis[16] accurate analysis and building code methods Shakesarising from an earthquake go through many changes due toseveral reasons before happening which will affect structuresin different ways Initial works in the field of buried pipelinesfocused preliminary on the main factor that is to say thepath through which waves move In addition as can be seen

from numerical calculations its effect has been considered inthe form of a semistatic factor

Regarding dynamic analyses done on buried pipelinesespecially on their bending points the impact of this factorhas omitted and pipes were only analysed by taking verticaldistribution and synchronous shakes throughout all pointsinto account Wave propagation velocity functions as aleading parameter to calculate strain Shear wave velocitywas used to calculate the extent of axial strain in areas having

0

500

1000

1500

2000

2500

3000

0 50 100 150 200

Bend

ing

tens

ion

Length (m)

Figure 7 Variation in the extent of maximum bending tensionsalong the pipeline with different final conditions

0

1000

2000

3000

4000

5000

0 50 100 150 200 250 300

Bend

ing

tens

ion

Length (m)

Figure 8 Variation in the extent of maximum axial tensions alongthe pipeline with different final conditions

0

1000

2000

3000

4000

5000

0 50 100 150 200

Bend

ing

tens

ion

Length (m)

Figure 9 Variation in the extent of maximum axial tensions alongthe pipeline with different final conditions

Shock and Vibration 5

focal length less than five times of the distance from focaldepth to the epicentre of an earthquake while Riley wavevelocity was utilized to calculate distances more than givenamount In a research study OrsquoRourke et al studied hori-zontal apparent speed for body waves ey developed ananalytical method to assess the shear wave angle of incidentSo apparent speed for shear waves is calculated as

Cs - apparent cs

sin θ (1)

where θ is the incident angle of the shear wave to thehorizontal and Cs is the velocity of shear waves in surfacesoil Phase velocity of the wave is the same apparent velocityUnlike body waves phase velocity depends upon frequencyWith regard to the Riley wave there is relation among wavelength (λ) frequency and phase velocity Figure 13ndash15 il-lustrate a scheme of Riley wave propagation with an ap-parent velocity

Wave propagation has been found to put strain on theground Measuring strain of ground is done by studyingsimple transitional movement of a wave having fixed shapeIt was assumed that velocity and movement of two pointsthroughout a propagation path simply differ in a time lag inwhich in turn it is a function of the distance between twopoints and the seismic wave velocity In the same tokenmaximum tensile or compressive strain of the earth (gє) inthe direction of wave propagation is measured as

εg VmC

(2)

where Vm is themaximum horizontal velocity of the earth inthe direction of wave propagation and C is the apparentpropagation velocity of the seismic wave To propagate aRiley wave strain parallel with the ground could be mea-sured using the equation above where C is replaced by thevalue of phase velocity according to the wave lengthequivalent to four times of the separation distance (thelength of the pipe located between two bridles which is aboutto analyse) e equation needs to be changed when thegiven direction is parallel to the line of wave propagationGenerally as can be seen from the figure below the wave hasangle in both vertical and horizontal plates So the equation

Figure 10 Demolition of pipesrsquo support due to soil liquefaction inthe Northbridge earthquake (1994)

Figure 11 Cracks observed in the joint between a restrained weakpipe and an unrestrained one [11]

Figure 12 Cracks in the pipe connected to the storage (ALA 2002)

P wave

S wave

Low wave

Rayleigh wave

Compression

Tension

Figure 13 Comparing R and S waves in designing pipes

Apparent velocity vax

True velocity V

Mrsquo Mrsquorsquo

M

θ

θ

z

x

Figure 14 Apparent propagation of a shear wave

6 Shock and Vibration

below is used to measure apparent wave velocity in thedirection of pipersquos axis

Cs - apparent cs

sin θ middot cos c (3)

Yeh [17] illustrated that maximum strain of the earth ismeasured by 45 θ c in given plates

34 Studying Seismic Behaviour of a Soil-Pipe System con-cerning Continuous Buried Pipelines A structure bearsbending or axial transformations after an earthquakeProviding satisfying plasticity in order to absorb transfor-mations due to earthquake without decrease in static loadingcapacity acts as an important design criterion Generallydeveloped axial strain throughout a continuous direct pipedepends upon such factors as shape of the earth transmittalwave length and soil-pipe interaction forces Althoughstrain of pipe and soil are assumed equal for small- tomedium-sized movements the same is not true for greatstrains because of existent slipping between soil and pipe Ithas been found to decrease pipe strain compared to that ofsoil Newmark [16] put forward a simple method to de-termine how the pipeline acts when earthquake waves arepropagated en other researchers such as Yeh revised it

Seismic movement of the earth which is defined as thehistory of velocity-time and velocity-displacement func-tions as a transmittal wave with fixed shape It suggests thattwo points along the propagation path simply shake by atime lag Inertia involved in small movement equations istoo small to be measured Later the assumption was studiedby many researchers and their works showed that it acts as areasonable engineering approximation It is assumed that norelative movement happens in the soil-pipe interaction andpipersquos strain equals to that of soil In addition OrsquoRourke andEl Hamadi developed an analytical method to estimatemaximum pipe strain

e method assumes that first axial strain in soil equalspipe strain arising from length friction between soil and pipeand second waves are propagated parallel to the axis of pipeIn a research study OrsquoRourke and Jeon [1] compared data

collected from three mentioned analytical methods when itcame to the continuous pipeline under the Riley waversquospropagation Besides the model put forward by Takada [18]suggested that pipe is modelled in the form of a shell having alength of 60 D adjacent to the fault but it could be in theform of an beam element where the distance from the pipe tothe fault is almost 300meters and the extent of soil and pipeslipping and strains are insignificant (Figure 16) All thingsbeing equal soil surrounded the pipe is modelled using soilsprings according to the seismic designing regulation ofburied oil and gas pipes [19]

In 2004 Takada et al reported on a newmodel accordingto changes in boundary conditions ey suggest that thepipe should be modelled in the junction with the fault in theform of a shell element due to local strain and big trans-formations just the same as before Moreover each point ofthe shell element is connected to three soil springs in axiallateral and vertical directions Finally the relation betweenthe axial force (f ) and increased length ΔL which is regardedto boundary conditions for nonelastic springs is measuredas

F(ΔL)

3EAfs2

1113970U016ΔL

23 0ltΔLltU0 (4)

3EAfsΔL minus 14U0

1113874 1113875

1113970σy2A2Efs

+U04

(5)

where Yσ acts as pipersquos yield stress and elasticity modulus Ithas been suggested that tensile rupture local buckling andthimble buckling are among the most significant damage tocontinuous pipes while tensile and compression ruptures ofpipe joints as well as local bending were the most commondamage observed in apart pipeline [20] Concerning mod-elling of continuous pipes Halabian and Hokmabadi [21]stimulated faulting and wave propagation in the laboratoryof Isfahan Technological University Iran and adoptedequivalent boundary conditions put forward by Takadawhen it came to boundary conditions related to the end ofthe pipe so they conducted a parametric study on the be-haviour of buried pipelines

Equivalent boundary

Axial spring damper

Equivalent boundary

Lateral spring damper

Vertical spring damper

Figure 15 Apparent propagation of an R wave strain of the ground and curvature results

Shock and Vibration 7

Rofooei and Qorbani [19] assumed a vertical wavepropagation in order to conduct a parametric study oncontinuous pipes under earthquake loadingey stimulatedthe pipe and surrounding soil through springs according tothe ALA regulation using ANSIS software Considering datacollected from effects of pipe and soil geometric changes ontheir relative displacement they observed increase in relo-cation in the soil-pipe boundary due to decrease in soilaggregation

35 e Seismic Susceptibility Model concerning BuriedPipelines Hazussr2i is a guideline on estimating damage tostructures due to the earthquake which was developed byFEMA and the national institute of the US Architecture It iscomprised of ways to estimate the extent of earthquakedamage to various structures including lifelines Accord-ingly the guideline suggests that leakage tends to happenbecause of earthquake waves in which 80 depends uponmaximum earth velocity and 20 is a function of earthrsquospermanent transformations while it has been found thatpipe breakage proves to be due to earthrsquos big transformationsin which 20 and 80 depend upon PGA and PGDrespectively

Furthermore the method divides pipes into two groupsincluding frangible and flexible As a result susceptibility offlexible pipes decreases by 70 e likelihood of soil liq-uefaction has been directly entered to the Hazus modelwhich is assumed as the most significant factor on pipedisplacement e algorithm concerning susceptibility ofburied pipes under earthquake waves was found by ana-lysing experimental data collected from four earthquakes inthe US and two in Mexico en data were adjusted to theHazus method

e guideline divides pipes into small and big groups inorder to estimate time required for reconstructing pipelinesdamaged in earthquakes Accordingly the small group in-cludes pipes having a diameter of 20 inch or less while othersare put in the big group e method also estimates daysrequired for reconstruction of the water supply system efollowing assumptions suggest how to measure days forrepair the pipeline It takes an equipped four-man team forfour and eight hours to repair a leaky and a broken piperespectively It takes an equipped four-man team for six and

twelve hours to repair a leaky and a broken pipe respec-tively ere is a linear link between repair program andtime As a result the extent of repairs done on a pipelinewhich needs (a) days within (b) days with a fixed number ofworkers is measured ba (Table 2)

36eSusceptibility IndexVI In this method the weightedcoefficient is assumed as a factor covering pipe diameter cdconditions of the ground cg magnitude of the earthquakebased on the Mercalli intensity scale ci pipe passage throughthe fault cf soil liquefaction c1 and potential land slideoccurrence potential Tables 3ndash10 give information aboutweighted coefficients Susceptibility of each part in thewastewater system is achieved by giving weight to above-mentioned factors in different conditions and then multi-plying the value by the weighted coefficient of each factorConsidering data from Table 10 and based on values ob-tained from forgoing equation (6) susceptibility of thewastewater system is divided into three groups includinghigh medium and low It is worth mentioning thatweighted coefficients concerning each factor have been se-lected based on maximum recorded damage to the buriedpipeline in past earthquakes Table 5 gives information aboutweighted coefficient regarding conditions of the groundbased on different types of soil In addition Table 6 illus-trates magnitude of an earthquake as well as correspondentimproved intensity scale (MMI) in PGA

VI cd middot cp middot cf middot cg middot ci middot cl middot cs (6)

4 Numerical Simulation

A complete set is comprised of software hardware datamodels algorithms and human resources for collectingpreparing organizing storing updating processing andanalysing different types of local data Such a system aims tomanage and handle information collected from the referenceplace in order to make sensible decisions e data modelindicates transformation of the real world by observingrelated geometrical relations and descriptive information toa reasonable and digital oneemodel represents all objectsin the form of points lines or polygon However topologicaldata aim to extract relations between phenomena Existing

Base springs

Longitudinal soil springs not shown

Overburden or uplift springs

Initial position

Design thawsettlement

Figure 16 Finite-element model of a shell element in collision with the fault

8 Shock and Vibration

relations between phenomena in local data function as partand particle of some GIS analysing systems In the rastermodel the whole map is divided into a set of small andregular cells called pixel e raster format is actuallycomposed of an nlowastm array of pixels

e geographical information system (GIS) has recentlyattracted the attention of different engineering fields e

ability to interpret and analyse data in such systems andsoftware enables us to review multiple parameters andfactors affecting different analyses and achieve reliable re-sults Research has proved the applicability of GIS to analysedata and extract results in the field of water and wastewaterengineering In the current research the most well-knownsoftware package appertain to geographical informationArcGIS Desktop 101 has been used to analyse data For thepurpose of analysis first softwarersquos default data and geo-graphical tiers called GIS READY were prepared eprocess was comprised of improving designing mistakes andthen doing a georeferencing operation

Since most of data were in the form of paper maps theywere first scanned and then by taking the scale of data intoaccount data were turned into a numerical one Finally withregard to available data as well as type of analysis all datawere changed into a roster model based on their effectiveparameters (Figure 17)

Table 2 Hazus equations concerning the ratio of damage to a buried pipeline

Type of pipe e ratio of damage to a PGV pipe per kilometer e ratio of damage to a PGD pipe per kilometerFragile RR 00001lowastPGV225 RR prob lowastPGD056Flexible RR 03 lowast 00001 lowastPGV225 RR 03 lowast prob lowastPGD056PR is defined as the extent of damage to the pipe per kilometerPGV (cmsminus1)PGD (inch)

Table 3 Weighted coefficient for diameter of a pipe

Coefficient cd Pipe diameter (d)Dlt 75mm 1675mmlt dlt 150mm 10150mmlt dlt 250mm 09250mmlt dlt 450mm 07450mmlt dlt 1000mm 05dgt 1000mm 04

Table 4 Weighted coefficient for type of pipe

Type of the pipeline Coefficient (cp)Soft cast iron 03Cast iron 10Ceramic 3Asbestos 25Poly ethylene 01Concrete 2

Table 5 Weighted coefficient for conditions of the ground

Type of soil CoefficientType I 05Type II 1Type III 2Type IV 29

Table 6 Weighted coefficient for magnitude of the earthquake

Magnitude of the earthquake CoefficientMMIlt 8 10PGAlt 025G8ltMMIlt 9 21025GltPGAlt 045G9ltMMIlt 10 24045GltPGAlt 06G10ltMMIlt 11 3006GltPGAlt 09G11ltMMI 35PGAgt 09G

Table 7 Weighted coefficient for passage of the pipeline throughthe fault

Passage of the pipeline through a fault CoefficientNo passage 1One passage 2Multiple passages 24

Table 8 Weighted coefficient for soil liquefaction

Liquefaction Coefficient0ltPL1lt 5 15ltPLlt 15 2PLgt 15 24

Table 9 Weighted coefficient for the land slide potential CS

Potential of the land slide CoefficientNo danger 1Medium danger 2High danger 24

Table 10 Classification of the extent of seismic susceptibility of thewastewater system

Color Susceptibility level VI indexGreen Low 0ltVIlt 5Orange Medium 5ltVIlt 12Red High VIgt 12

Shock and Vibration 9

41 Statistical Population Gorgan a city in Golestan Iranwas selected in the current case study research It has beenthe first city in the province equipped with the wastewatersystem As the city experiences dozens of small earthquakesevery day it is worth studying susceptibility of the waste-water system to earthquake e wastewater system is124meters in length (Figure 18)

First maps developed in AutoCAD software pertinent tothe Gorgan wastewater system were collected in order toassess the extent of damage to the system due to earthquakesNext maps were turned into GIS data Both 2 and 10 percentdanger analysis maps were adjusted to aerial photos andthen corrected ones were entered into GIS software tomeasure the seismic susceptibility ratio under maximumland movement

42 Sampling Method and Sample Size In the current re-search two types of data including maps of seismic analysisand wastewater pipelinesrsquo code were used e former in-cludes curves aligned with velocity of potential approachesof the vertical element which are pertinent to a return periodof 75 years for 2 PGA and a return period of 475 years for10 PGA for an estimated 50 year service life

43 e Map of Selected Wastewater System e Gorganwater and wastewater organization has provided the re-searcher with given maps as well as a file containing pipe-linesrsquo codes (Figures 19 and 20) en the file entered intothe GIS software and improved

44 Data Analysis Research variables include characteris-tics of pipes as well as velocity of the earthquake which havebeen drawn by adjusting rough maps of earthquake velocityand the cityrsquos wastewater system (Figures 21 and 22)

5 Results and Discussion

Raw data were put into GIS software as input and twooutput data were obtained Figures 23 and 24 illustrate the

Iteratefeature

Select layerby location

Summarystatistics

Get fieldvalue

Calculatefield End

Figure 17 e algorithm determining the extent of damage observed under an earthquake wave in GIS

Figure 18 Geographical location of Gorgan

Figure 19 e organization map of the urban wastewater system

Diameter150200250300400500600700800

Figure 20 e map of Borujen wastewater system (diameter ofpipes)

033

031

Figure 21 e PGA10 map and Borujenrsquos wastewater system

10 Shock and Vibration

extent of damage to pipes using Hazus based on two dif-ferent earthquake velocities namely PGA 2 and PGA 10

Figures 25 and 26 give information about the extent ofdamage under two different earthquakes according to the VImethod

6 Conclusion

Comparing HAUS and VI methods suggests that the formergives more accurate and detailed data so it enables au-thorities to make better decisions for boosting and planningstructures and finding their susceptible points Moreover asthe method helps to find out the extent of damage structureswould suffer after occurrence of an earthquake recon-struction process would be done quickly and precisely

Considering the point that the region has always beenearthquake-prone reviewing data obtained frommaps showa high level of damage Maps are indicating the first pre-diction of the current research that is to say susceptibility ofthe wastewater system to occurrence of any earthquake so itfocuses on the necessity for replacing existent pipelines withmore resistant ones

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

049

052

Figure 22 e PGA2 map and wastewater system

0867840466ndash37318188373181886ndash6595797256595797252ndash94597756

9459775645ndash12323754

1232375405ndash151877321518773244ndash180517101805171083ndash20915689

2091568922ndash237796672377966762ndash26643646

Number of repair10

Figure 23 e total number of Hazus SR2 damage underPGA10

494688108017143028310733633443371853167709116841346914669157521636517644

Number of repair2value

Figure 24 e total number of Hazus SR2 damage under PGA2

Figure 25 e total number of damage under PGA2 accordingto the VI method

Figure 26 e total number of damage under PGA10 accordingto the VI method

Shock and Vibration 11

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T D OrsquoRourke and S S Jeon ldquoFactors affecting the earth-quake damage of water distribution systems in optimizingpost-earthquake lifeline system in optimizing post-life linesystem reliabilityrdquo in Proceedings of the Fifth US Conferenceon Lifeline Earthquake Engineering ASCE Seattle WC USA1999

[2] U Albayrak A Loai and M Morshid ldquoEvaluation of seismicperformance of steel lattice transmission towersrdquo Civil En-gineering Journal vol 6 no 10 pp 1ndash21 2020

[3] B Cai and M H Golestan ldquoTowards bayesian quantificationof permeability in micro-scale porous structuresrdquo e Da-tabase of Micro Networks vol 1 no 4 pp 1ndash13 2020

[4] H Shah and S Chu ldquoSeismic analysis of undergroundstructural elementsrdquo Journal of the Power Division vol 100no 1 pp 53ndash62 1974

[5] E C Goodling ldquoBuried pipingndashan analysis procedure up-daterdquo in Proceedings of the International Symposium onLifeline Earthquake Engineering vol 77 pp 225ndash237 ASMEPortland Oregon May 1983

[6] M Shinozuka and T Koike ldquoEstimation of structural strain inunderground lifeline pipesrdquo Lifeline Earthquake Engineering-Buried Pipeline Seismic Risk and Instrumentation vol 34pp 31ndash48 1979

[7] S Takada and K Tanabe ldquoree-dimensional seismic re-sponse analysis of buried continuous or jointed pipelinesrdquoJournal of Pressure Vessel Technology vol 109 no 1pp 80ndash87 1987

[8] S Takada A Carlo S Bo and X Wuhu Current State of theArts on Pipeline Earthquake Engineering in Japan eConstruction Engineering Research Foundation PuneMaharashtra India vol 1 1992

[9] L Dai D Wang T Wang Q Feng and X Yang ldquoAnalysisand comparison of long-distance pipeline failuresrdquo Journal ofPetroleum Engineering vol 2017 no 1 7 pages Article ID3174636 2017

[10] Y Yang S Yang Z Li et al ldquoAnalysis of hazard area ofdispersion caused by leakage from underground gas-storagecaverns in salt rockrdquo Advances in Civil Engineering vol 2020no 1 11 pages

[11] M Cubrinovski Geotechnical Reconnaissance of the 2010Darfield (New Zealand) Earthquake University of Canter-bury Christchurch New Zealand 2010

[12] Y Maruyama and F Yamazaki ldquoConstruction of fragilitycurve for water distribution pipes based on damage datasetsfrom recent earthquakes in Japanrdquo in Proceedings of the 9thUS National and 10th Canadian Conference on EarthquakeEngineering Toronto ON Canada July 2010

[13] J F Bird and J J Bommer ldquoEarthquake losses due to groundfailurerdquo Engineering Geology vol 75 no 2 pp 147ndash179 2004

[14] M Zare and S Wilkinson ldquoEarthquake damage in wastewatersystem and post earthquake repair methodslimitation andpractcerdquo in Proceedings of the Australian Earthquake Engi-neering Society Conference Novotel Bavossa Valley RwsortBarossa Valley South Australia November 2011

[15] R T Eguchi ldquoSeismic vulnerability models for undergroundpipesrdquo in Proceedings of the International Symposium onEarthquakeBehavior and Safety of Oil and Gas Storage

Facilities Buried Pipelines and Equipment American Societyof Mechanical Engineers (ASME) New York NY USAJanuary 1983

[16] N M Newmark ldquoSeismic design criteria for structures andfacilities Trans-Alaska pipeline systemrdquo in Proceedings of theUS National Conference on Earthquake Engineering Earth-quake Engineering Institute San Francisco CA USA June1975

[17] G Yeh ldquoSeismic analysis of slender buried beamsrdquo eBulletin of the Seismological Society of America vol 64o no 5pp 1551ndash1562 1974

[18] S Takada N Hassani and K Fukuda ldquoA new proposal forsimplified design of buried steel pipes crossing active faultsrdquoEarthquake Engineering amp Structural Dynamics vol 30 no 8pp 1243ndash1257 2001

[19] F R Rofooei and R Qorbani ldquoA parametric study on seismicbehavior of continuous buried pipeline due to wave propa-gationrdquo in Proceedings of the 14th World Conference onEarthquake Engineering Beijing China October 2008

[20] M Hosseini and S Jallili ldquoAssessment of the nonlineearbehavior of connection in water distribution networks fortheir seimic evaluationrdquo Procedia Engineering vol 14pp 2878ndash2883 2011

[21] A M Halabian and T Hokmabadi ldquoA new hybrid model forrigorous analysis of buried pipelines under general faultingaccounting for material and geometrical non-linearities withfocusing on corrugated HDPE pipelinesrdquo Soil Dynamics andEarthquake Engineering vol 115 pp 1ndash17 2018

12 Shock and Vibration

relocation due to subsidence is less than that of due to soilliquefaction Notwithstanding subsidence is of importancebecause of making heterogeneous dislocations in soil

32 Features of the Pipeline Affecting Susceptibility of theBuried Pipelines due to an Earthquake Most of parametersaffecting susceptibility of buried pipelines due to anearthquake have much to do with characteristics of thepipeline Prior studies showed that type of the pipe plays apivotal role To put it simply its flexibility helps the pipingsystem because it leads to easily movement of soil along withthe pipe which prevent the pipe from bursting during anearthquake Increase in the internal diameter of pipelinesdecreases both bending and axial tensions due to affectingsoil-pipe interaction Final conditions have marginal effecton tensions created in cross sections when it comes to lengthof pipe With regard to data collected from the analysis it ishighly likely that the pipe will rupture at its junction withother installations such as manholes and storages thanother sections of the pipeline (Figure 7ndash9)

e pipeline bears lateral loads during an earthquakewhich it oscillates pipes and cuts their connections with thesaddle However bracing spaces helps the system not to bedevastated Figure 10 illustrates demolition of pipesrsquo supportdue to soil liquefaction in the Northbridge earthquake(1994)

However seismic and flexible joints have been found tosuggest great function during an earthquake which it leads todecrease in demolition of the water supply system On theother hand accruing to data collected from prior researchcontinuous pipes such as the ones made up of steel withwelded joints have shown greater function than sectionalpipes with lots of joints In addition the extent of demolitionobserved for asbestos pipes in Loma Prieta (1989) andNorthridge (1994) earthquakes was less than that recordedfor Mexico City earthquake (1985)

Researchers also argue that connection behaviour wouldprove to be linear when pipesrsquo relative rotation is 005 radianMoreover bending experiments on fittings used in flexiblecast iron pipes having rubber-made washers and differentdiameters showed that rotation of joints is done around thepipe Improper hardness distribution is the leading cause ofmost of the destructions of the water supply system As aresult relocations arising from such shakes are different andcause to break joints between pipes (Figures 11 and 12)

33 Methods of Studying the Seismic Behaviour of a PipelineWith regard to the destructions left after earthquakes re-searchers set the stage to conduct a comprehensive study inorder to develop some methods to find how seismic be-haviour affects the pipelines e methods are generallydivided into three groups including approximate analysis[16] accurate analysis and building code methods Shakesarising from an earthquake go through many changes due toseveral reasons before happening which will affect structuresin different ways Initial works in the field of buried pipelinesfocused preliminary on the main factor that is to say thepath through which waves move In addition as can be seen

from numerical calculations its effect has been considered inthe form of a semistatic factor

Regarding dynamic analyses done on buried pipelinesespecially on their bending points the impact of this factorhas omitted and pipes were only analysed by taking verticaldistribution and synchronous shakes throughout all pointsinto account Wave propagation velocity functions as aleading parameter to calculate strain Shear wave velocitywas used to calculate the extent of axial strain in areas having

0

500

1000

1500

2000

2500

3000

0 50 100 150 200

Bend

ing

tens

ion

Length (m)

Figure 7 Variation in the extent of maximum bending tensionsalong the pipeline with different final conditions

0

1000

2000

3000

4000

5000

0 50 100 150 200 250 300

Bend

ing

tens

ion

Length (m)

Figure 8 Variation in the extent of maximum axial tensions alongthe pipeline with different final conditions

0

1000

2000

3000

4000

5000

0 50 100 150 200

Bend

ing

tens

ion

Length (m)

Figure 9 Variation in the extent of maximum axial tensions alongthe pipeline with different final conditions

Shock and Vibration 5

focal length less than five times of the distance from focaldepth to the epicentre of an earthquake while Riley wavevelocity was utilized to calculate distances more than givenamount In a research study OrsquoRourke et al studied hori-zontal apparent speed for body waves ey developed ananalytical method to assess the shear wave angle of incidentSo apparent speed for shear waves is calculated as

Cs - apparent cs

sin θ (1)

where θ is the incident angle of the shear wave to thehorizontal and Cs is the velocity of shear waves in surfacesoil Phase velocity of the wave is the same apparent velocityUnlike body waves phase velocity depends upon frequencyWith regard to the Riley wave there is relation among wavelength (λ) frequency and phase velocity Figure 13ndash15 il-lustrate a scheme of Riley wave propagation with an ap-parent velocity

Wave propagation has been found to put strain on theground Measuring strain of ground is done by studyingsimple transitional movement of a wave having fixed shapeIt was assumed that velocity and movement of two pointsthroughout a propagation path simply differ in a time lag inwhich in turn it is a function of the distance between twopoints and the seismic wave velocity In the same tokenmaximum tensile or compressive strain of the earth (gє) inthe direction of wave propagation is measured as

εg VmC

(2)

where Vm is themaximum horizontal velocity of the earth inthe direction of wave propagation and C is the apparentpropagation velocity of the seismic wave To propagate aRiley wave strain parallel with the ground could be mea-sured using the equation above where C is replaced by thevalue of phase velocity according to the wave lengthequivalent to four times of the separation distance (thelength of the pipe located between two bridles which is aboutto analyse) e equation needs to be changed when thegiven direction is parallel to the line of wave propagationGenerally as can be seen from the figure below the wave hasangle in both vertical and horizontal plates So the equation

Figure 10 Demolition of pipesrsquo support due to soil liquefaction inthe Northbridge earthquake (1994)

Figure 11 Cracks observed in the joint between a restrained weakpipe and an unrestrained one [11]

Figure 12 Cracks in the pipe connected to the storage (ALA 2002)

P wave

S wave

Low wave

Rayleigh wave

Compression

Tension

Figure 13 Comparing R and S waves in designing pipes

Apparent velocity vax

True velocity V

Mrsquo Mrsquorsquo

M

θ

θ

z

x

Figure 14 Apparent propagation of a shear wave

6 Shock and Vibration

below is used to measure apparent wave velocity in thedirection of pipersquos axis

Cs - apparent cs

sin θ middot cos c (3)

Yeh [17] illustrated that maximum strain of the earth ismeasured by 45 θ c in given plates

34 Studying Seismic Behaviour of a Soil-Pipe System con-cerning Continuous Buried Pipelines A structure bearsbending or axial transformations after an earthquakeProviding satisfying plasticity in order to absorb transfor-mations due to earthquake without decrease in static loadingcapacity acts as an important design criterion Generallydeveloped axial strain throughout a continuous direct pipedepends upon such factors as shape of the earth transmittalwave length and soil-pipe interaction forces Althoughstrain of pipe and soil are assumed equal for small- tomedium-sized movements the same is not true for greatstrains because of existent slipping between soil and pipe Ithas been found to decrease pipe strain compared to that ofsoil Newmark [16] put forward a simple method to de-termine how the pipeline acts when earthquake waves arepropagated en other researchers such as Yeh revised it

Seismic movement of the earth which is defined as thehistory of velocity-time and velocity-displacement func-tions as a transmittal wave with fixed shape It suggests thattwo points along the propagation path simply shake by atime lag Inertia involved in small movement equations istoo small to be measured Later the assumption was studiedby many researchers and their works showed that it acts as areasonable engineering approximation It is assumed that norelative movement happens in the soil-pipe interaction andpipersquos strain equals to that of soil In addition OrsquoRourke andEl Hamadi developed an analytical method to estimatemaximum pipe strain

e method assumes that first axial strain in soil equalspipe strain arising from length friction between soil and pipeand second waves are propagated parallel to the axis of pipeIn a research study OrsquoRourke and Jeon [1] compared data

collected from three mentioned analytical methods when itcame to the continuous pipeline under the Riley waversquospropagation Besides the model put forward by Takada [18]suggested that pipe is modelled in the form of a shell having alength of 60 D adjacent to the fault but it could be in theform of an beam element where the distance from the pipe tothe fault is almost 300meters and the extent of soil and pipeslipping and strains are insignificant (Figure 16) All thingsbeing equal soil surrounded the pipe is modelled using soilsprings according to the seismic designing regulation ofburied oil and gas pipes [19]

In 2004 Takada et al reported on a newmodel accordingto changes in boundary conditions ey suggest that thepipe should be modelled in the junction with the fault in theform of a shell element due to local strain and big trans-formations just the same as before Moreover each point ofthe shell element is connected to three soil springs in axiallateral and vertical directions Finally the relation betweenthe axial force (f ) and increased length ΔL which is regardedto boundary conditions for nonelastic springs is measuredas

F(ΔL)

3EAfs2

1113970U016ΔL

23 0ltΔLltU0 (4)

3EAfsΔL minus 14U0

1113874 1113875

1113970σy2A2Efs

+U04

(5)

where Yσ acts as pipersquos yield stress and elasticity modulus Ithas been suggested that tensile rupture local buckling andthimble buckling are among the most significant damage tocontinuous pipes while tensile and compression ruptures ofpipe joints as well as local bending were the most commondamage observed in apart pipeline [20] Concerning mod-elling of continuous pipes Halabian and Hokmabadi [21]stimulated faulting and wave propagation in the laboratoryof Isfahan Technological University Iran and adoptedequivalent boundary conditions put forward by Takadawhen it came to boundary conditions related to the end ofthe pipe so they conducted a parametric study on the be-haviour of buried pipelines

Equivalent boundary

Axial spring damper

Equivalent boundary

Lateral spring damper

Vertical spring damper

Figure 15 Apparent propagation of an R wave strain of the ground and curvature results

Shock and Vibration 7

Rofooei and Qorbani [19] assumed a vertical wavepropagation in order to conduct a parametric study oncontinuous pipes under earthquake loadingey stimulatedthe pipe and surrounding soil through springs according tothe ALA regulation using ANSIS software Considering datacollected from effects of pipe and soil geometric changes ontheir relative displacement they observed increase in relo-cation in the soil-pipe boundary due to decrease in soilaggregation

35 e Seismic Susceptibility Model concerning BuriedPipelines Hazussr2i is a guideline on estimating damage tostructures due to the earthquake which was developed byFEMA and the national institute of the US Architecture It iscomprised of ways to estimate the extent of earthquakedamage to various structures including lifelines Accord-ingly the guideline suggests that leakage tends to happenbecause of earthquake waves in which 80 depends uponmaximum earth velocity and 20 is a function of earthrsquospermanent transformations while it has been found thatpipe breakage proves to be due to earthrsquos big transformationsin which 20 and 80 depend upon PGA and PGDrespectively

Furthermore the method divides pipes into two groupsincluding frangible and flexible As a result susceptibility offlexible pipes decreases by 70 e likelihood of soil liq-uefaction has been directly entered to the Hazus modelwhich is assumed as the most significant factor on pipedisplacement e algorithm concerning susceptibility ofburied pipes under earthquake waves was found by ana-lysing experimental data collected from four earthquakes inthe US and two in Mexico en data were adjusted to theHazus method

e guideline divides pipes into small and big groups inorder to estimate time required for reconstructing pipelinesdamaged in earthquakes Accordingly the small group in-cludes pipes having a diameter of 20 inch or less while othersare put in the big group e method also estimates daysrequired for reconstruction of the water supply system efollowing assumptions suggest how to measure days forrepair the pipeline It takes an equipped four-man team forfour and eight hours to repair a leaky and a broken piperespectively It takes an equipped four-man team for six and

twelve hours to repair a leaky and a broken pipe respec-tively ere is a linear link between repair program andtime As a result the extent of repairs done on a pipelinewhich needs (a) days within (b) days with a fixed number ofworkers is measured ba (Table 2)

36eSusceptibility IndexVI In this method the weightedcoefficient is assumed as a factor covering pipe diameter cdconditions of the ground cg magnitude of the earthquakebased on the Mercalli intensity scale ci pipe passage throughthe fault cf soil liquefaction c1 and potential land slideoccurrence potential Tables 3ndash10 give information aboutweighted coefficients Susceptibility of each part in thewastewater system is achieved by giving weight to above-mentioned factors in different conditions and then multi-plying the value by the weighted coefficient of each factorConsidering data from Table 10 and based on values ob-tained from forgoing equation (6) susceptibility of thewastewater system is divided into three groups includinghigh medium and low It is worth mentioning thatweighted coefficients concerning each factor have been se-lected based on maximum recorded damage to the buriedpipeline in past earthquakes Table 5 gives information aboutweighted coefficient regarding conditions of the groundbased on different types of soil In addition Table 6 illus-trates magnitude of an earthquake as well as correspondentimproved intensity scale (MMI) in PGA

VI cd middot cp middot cf middot cg middot ci middot cl middot cs (6)

4 Numerical Simulation

A complete set is comprised of software hardware datamodels algorithms and human resources for collectingpreparing organizing storing updating processing andanalysing different types of local data Such a system aims tomanage and handle information collected from the referenceplace in order to make sensible decisions e data modelindicates transformation of the real world by observingrelated geometrical relations and descriptive information toa reasonable and digital oneemodel represents all objectsin the form of points lines or polygon However topologicaldata aim to extract relations between phenomena Existing

Base springs

Longitudinal soil springs not shown

Overburden or uplift springs

Initial position

Design thawsettlement

Figure 16 Finite-element model of a shell element in collision with the fault

8 Shock and Vibration

relations between phenomena in local data function as partand particle of some GIS analysing systems In the rastermodel the whole map is divided into a set of small andregular cells called pixel e raster format is actuallycomposed of an nlowastm array of pixels

e geographical information system (GIS) has recentlyattracted the attention of different engineering fields e

ability to interpret and analyse data in such systems andsoftware enables us to review multiple parameters andfactors affecting different analyses and achieve reliable re-sults Research has proved the applicability of GIS to analysedata and extract results in the field of water and wastewaterengineering In the current research the most well-knownsoftware package appertain to geographical informationArcGIS Desktop 101 has been used to analyse data For thepurpose of analysis first softwarersquos default data and geo-graphical tiers called GIS READY were prepared eprocess was comprised of improving designing mistakes andthen doing a georeferencing operation

Since most of data were in the form of paper maps theywere first scanned and then by taking the scale of data intoaccount data were turned into a numerical one Finally withregard to available data as well as type of analysis all datawere changed into a roster model based on their effectiveparameters (Figure 17)

Table 2 Hazus equations concerning the ratio of damage to a buried pipeline

Type of pipe e ratio of damage to a PGV pipe per kilometer e ratio of damage to a PGD pipe per kilometerFragile RR 00001lowastPGV225 RR prob lowastPGD056Flexible RR 03 lowast 00001 lowastPGV225 RR 03 lowast prob lowastPGD056PR is defined as the extent of damage to the pipe per kilometerPGV (cmsminus1)PGD (inch)

Table 3 Weighted coefficient for diameter of a pipe

Coefficient cd Pipe diameter (d)Dlt 75mm 1675mmlt dlt 150mm 10150mmlt dlt 250mm 09250mmlt dlt 450mm 07450mmlt dlt 1000mm 05dgt 1000mm 04

Table 4 Weighted coefficient for type of pipe

Type of the pipeline Coefficient (cp)Soft cast iron 03Cast iron 10Ceramic 3Asbestos 25Poly ethylene 01Concrete 2

Table 5 Weighted coefficient for conditions of the ground

Type of soil CoefficientType I 05Type II 1Type III 2Type IV 29

Table 6 Weighted coefficient for magnitude of the earthquake

Magnitude of the earthquake CoefficientMMIlt 8 10PGAlt 025G8ltMMIlt 9 21025GltPGAlt 045G9ltMMIlt 10 24045GltPGAlt 06G10ltMMIlt 11 3006GltPGAlt 09G11ltMMI 35PGAgt 09G

Table 7 Weighted coefficient for passage of the pipeline throughthe fault

Passage of the pipeline through a fault CoefficientNo passage 1One passage 2Multiple passages 24

Table 8 Weighted coefficient for soil liquefaction

Liquefaction Coefficient0ltPL1lt 5 15ltPLlt 15 2PLgt 15 24

Table 9 Weighted coefficient for the land slide potential CS

Potential of the land slide CoefficientNo danger 1Medium danger 2High danger 24

Table 10 Classification of the extent of seismic susceptibility of thewastewater system

Color Susceptibility level VI indexGreen Low 0ltVIlt 5Orange Medium 5ltVIlt 12Red High VIgt 12

Shock and Vibration 9

41 Statistical Population Gorgan a city in Golestan Iranwas selected in the current case study research It has beenthe first city in the province equipped with the wastewatersystem As the city experiences dozens of small earthquakesevery day it is worth studying susceptibility of the waste-water system to earthquake e wastewater system is124meters in length (Figure 18)

First maps developed in AutoCAD software pertinent tothe Gorgan wastewater system were collected in order toassess the extent of damage to the system due to earthquakesNext maps were turned into GIS data Both 2 and 10 percentdanger analysis maps were adjusted to aerial photos andthen corrected ones were entered into GIS software tomeasure the seismic susceptibility ratio under maximumland movement

42 Sampling Method and Sample Size In the current re-search two types of data including maps of seismic analysisand wastewater pipelinesrsquo code were used e former in-cludes curves aligned with velocity of potential approachesof the vertical element which are pertinent to a return periodof 75 years for 2 PGA and a return period of 475 years for10 PGA for an estimated 50 year service life

43 e Map of Selected Wastewater System e Gorganwater and wastewater organization has provided the re-searcher with given maps as well as a file containing pipe-linesrsquo codes (Figures 19 and 20) en the file entered intothe GIS software and improved

44 Data Analysis Research variables include characteris-tics of pipes as well as velocity of the earthquake which havebeen drawn by adjusting rough maps of earthquake velocityand the cityrsquos wastewater system (Figures 21 and 22)

5 Results and Discussion

Raw data were put into GIS software as input and twooutput data were obtained Figures 23 and 24 illustrate the

Iteratefeature

Select layerby location

Summarystatistics

Get fieldvalue

Calculatefield End

Figure 17 e algorithm determining the extent of damage observed under an earthquake wave in GIS

Figure 18 Geographical location of Gorgan

Figure 19 e organization map of the urban wastewater system

Diameter150200250300400500600700800

Figure 20 e map of Borujen wastewater system (diameter ofpipes)

033

031

Figure 21 e PGA10 map and Borujenrsquos wastewater system

10 Shock and Vibration

extent of damage to pipes using Hazus based on two dif-ferent earthquake velocities namely PGA 2 and PGA 10

Figures 25 and 26 give information about the extent ofdamage under two different earthquakes according to the VImethod

6 Conclusion

Comparing HAUS and VI methods suggests that the formergives more accurate and detailed data so it enables au-thorities to make better decisions for boosting and planningstructures and finding their susceptible points Moreover asthe method helps to find out the extent of damage structureswould suffer after occurrence of an earthquake recon-struction process would be done quickly and precisely

Considering the point that the region has always beenearthquake-prone reviewing data obtained frommaps showa high level of damage Maps are indicating the first pre-diction of the current research that is to say susceptibility ofthe wastewater system to occurrence of any earthquake so itfocuses on the necessity for replacing existent pipelines withmore resistant ones

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

049

052

Figure 22 e PGA2 map and wastewater system

0867840466ndash37318188373181886ndash6595797256595797252ndash94597756

9459775645ndash12323754

1232375405ndash151877321518773244ndash180517101805171083ndash20915689

2091568922ndash237796672377966762ndash26643646

Number of repair10

Figure 23 e total number of Hazus SR2 damage underPGA10

494688108017143028310733633443371853167709116841346914669157521636517644

Number of repair2value

Figure 24 e total number of Hazus SR2 damage under PGA2

Figure 25 e total number of damage under PGA2 accordingto the VI method

Figure 26 e total number of damage under PGA10 accordingto the VI method

Shock and Vibration 11

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T D OrsquoRourke and S S Jeon ldquoFactors affecting the earth-quake damage of water distribution systems in optimizingpost-earthquake lifeline system in optimizing post-life linesystem reliabilityrdquo in Proceedings of the Fifth US Conferenceon Lifeline Earthquake Engineering ASCE Seattle WC USA1999

[2] U Albayrak A Loai and M Morshid ldquoEvaluation of seismicperformance of steel lattice transmission towersrdquo Civil En-gineering Journal vol 6 no 10 pp 1ndash21 2020

[3] B Cai and M H Golestan ldquoTowards bayesian quantificationof permeability in micro-scale porous structuresrdquo e Da-tabase of Micro Networks vol 1 no 4 pp 1ndash13 2020

[4] H Shah and S Chu ldquoSeismic analysis of undergroundstructural elementsrdquo Journal of the Power Division vol 100no 1 pp 53ndash62 1974

[5] E C Goodling ldquoBuried pipingndashan analysis procedure up-daterdquo in Proceedings of the International Symposium onLifeline Earthquake Engineering vol 77 pp 225ndash237 ASMEPortland Oregon May 1983

[6] M Shinozuka and T Koike ldquoEstimation of structural strain inunderground lifeline pipesrdquo Lifeline Earthquake Engineering-Buried Pipeline Seismic Risk and Instrumentation vol 34pp 31ndash48 1979

[7] S Takada and K Tanabe ldquoree-dimensional seismic re-sponse analysis of buried continuous or jointed pipelinesrdquoJournal of Pressure Vessel Technology vol 109 no 1pp 80ndash87 1987

[8] S Takada A Carlo S Bo and X Wuhu Current State of theArts on Pipeline Earthquake Engineering in Japan eConstruction Engineering Research Foundation PuneMaharashtra India vol 1 1992

[9] L Dai D Wang T Wang Q Feng and X Yang ldquoAnalysisand comparison of long-distance pipeline failuresrdquo Journal ofPetroleum Engineering vol 2017 no 1 7 pages Article ID3174636 2017

[10] Y Yang S Yang Z Li et al ldquoAnalysis of hazard area ofdispersion caused by leakage from underground gas-storagecaverns in salt rockrdquo Advances in Civil Engineering vol 2020no 1 11 pages

[11] M Cubrinovski Geotechnical Reconnaissance of the 2010Darfield (New Zealand) Earthquake University of Canter-bury Christchurch New Zealand 2010

[12] Y Maruyama and F Yamazaki ldquoConstruction of fragilitycurve for water distribution pipes based on damage datasetsfrom recent earthquakes in Japanrdquo in Proceedings of the 9thUS National and 10th Canadian Conference on EarthquakeEngineering Toronto ON Canada July 2010

[13] J F Bird and J J Bommer ldquoEarthquake losses due to groundfailurerdquo Engineering Geology vol 75 no 2 pp 147ndash179 2004

[14] M Zare and S Wilkinson ldquoEarthquake damage in wastewatersystem and post earthquake repair methodslimitation andpractcerdquo in Proceedings of the Australian Earthquake Engi-neering Society Conference Novotel Bavossa Valley RwsortBarossa Valley South Australia November 2011

[15] R T Eguchi ldquoSeismic vulnerability models for undergroundpipesrdquo in Proceedings of the International Symposium onEarthquakeBehavior and Safety of Oil and Gas Storage

Facilities Buried Pipelines and Equipment American Societyof Mechanical Engineers (ASME) New York NY USAJanuary 1983

[16] N M Newmark ldquoSeismic design criteria for structures andfacilities Trans-Alaska pipeline systemrdquo in Proceedings of theUS National Conference on Earthquake Engineering Earth-quake Engineering Institute San Francisco CA USA June1975

[17] G Yeh ldquoSeismic analysis of slender buried beamsrdquo eBulletin of the Seismological Society of America vol 64o no 5pp 1551ndash1562 1974

[18] S Takada N Hassani and K Fukuda ldquoA new proposal forsimplified design of buried steel pipes crossing active faultsrdquoEarthquake Engineering amp Structural Dynamics vol 30 no 8pp 1243ndash1257 2001

[19] F R Rofooei and R Qorbani ldquoA parametric study on seismicbehavior of continuous buried pipeline due to wave propa-gationrdquo in Proceedings of the 14th World Conference onEarthquake Engineering Beijing China October 2008

[20] M Hosseini and S Jallili ldquoAssessment of the nonlineearbehavior of connection in water distribution networks fortheir seimic evaluationrdquo Procedia Engineering vol 14pp 2878ndash2883 2011

[21] A M Halabian and T Hokmabadi ldquoA new hybrid model forrigorous analysis of buried pipelines under general faultingaccounting for material and geometrical non-linearities withfocusing on corrugated HDPE pipelinesrdquo Soil Dynamics andEarthquake Engineering vol 115 pp 1ndash17 2018

12 Shock and Vibration

focal length less than five times of the distance from focaldepth to the epicentre of an earthquake while Riley wavevelocity was utilized to calculate distances more than givenamount In a research study OrsquoRourke et al studied hori-zontal apparent speed for body waves ey developed ananalytical method to assess the shear wave angle of incidentSo apparent speed for shear waves is calculated as

Cs - apparent cs

sin θ (1)

where θ is the incident angle of the shear wave to thehorizontal and Cs is the velocity of shear waves in surfacesoil Phase velocity of the wave is the same apparent velocityUnlike body waves phase velocity depends upon frequencyWith regard to the Riley wave there is relation among wavelength (λ) frequency and phase velocity Figure 13ndash15 il-lustrate a scheme of Riley wave propagation with an ap-parent velocity

Wave propagation has been found to put strain on theground Measuring strain of ground is done by studyingsimple transitional movement of a wave having fixed shapeIt was assumed that velocity and movement of two pointsthroughout a propagation path simply differ in a time lag inwhich in turn it is a function of the distance between twopoints and the seismic wave velocity In the same tokenmaximum tensile or compressive strain of the earth (gє) inthe direction of wave propagation is measured as

εg VmC

(2)

where Vm is themaximum horizontal velocity of the earth inthe direction of wave propagation and C is the apparentpropagation velocity of the seismic wave To propagate aRiley wave strain parallel with the ground could be mea-sured using the equation above where C is replaced by thevalue of phase velocity according to the wave lengthequivalent to four times of the separation distance (thelength of the pipe located between two bridles which is aboutto analyse) e equation needs to be changed when thegiven direction is parallel to the line of wave propagationGenerally as can be seen from the figure below the wave hasangle in both vertical and horizontal plates So the equation

Figure 10 Demolition of pipesrsquo support due to soil liquefaction inthe Northbridge earthquake (1994)

Figure 11 Cracks observed in the joint between a restrained weakpipe and an unrestrained one [11]

Figure 12 Cracks in the pipe connected to the storage (ALA 2002)

P wave

S wave

Low wave

Rayleigh wave

Compression

Tension

Figure 13 Comparing R and S waves in designing pipes

Apparent velocity vax

True velocity V

Mrsquo Mrsquorsquo

M

θ

θ

z

x

Figure 14 Apparent propagation of a shear wave

6 Shock and Vibration

below is used to measure apparent wave velocity in thedirection of pipersquos axis

Cs - apparent cs

sin θ middot cos c (3)

Yeh [17] illustrated that maximum strain of the earth ismeasured by 45 θ c in given plates

34 Studying Seismic Behaviour of a Soil-Pipe System con-cerning Continuous Buried Pipelines A structure bearsbending or axial transformations after an earthquakeProviding satisfying plasticity in order to absorb transfor-mations due to earthquake without decrease in static loadingcapacity acts as an important design criterion Generallydeveloped axial strain throughout a continuous direct pipedepends upon such factors as shape of the earth transmittalwave length and soil-pipe interaction forces Althoughstrain of pipe and soil are assumed equal for small- tomedium-sized movements the same is not true for greatstrains because of existent slipping between soil and pipe Ithas been found to decrease pipe strain compared to that ofsoil Newmark [16] put forward a simple method to de-termine how the pipeline acts when earthquake waves arepropagated en other researchers such as Yeh revised it

Seismic movement of the earth which is defined as thehistory of velocity-time and velocity-displacement func-tions as a transmittal wave with fixed shape It suggests thattwo points along the propagation path simply shake by atime lag Inertia involved in small movement equations istoo small to be measured Later the assumption was studiedby many researchers and their works showed that it acts as areasonable engineering approximation It is assumed that norelative movement happens in the soil-pipe interaction andpipersquos strain equals to that of soil In addition OrsquoRourke andEl Hamadi developed an analytical method to estimatemaximum pipe strain

e method assumes that first axial strain in soil equalspipe strain arising from length friction between soil and pipeand second waves are propagated parallel to the axis of pipeIn a research study OrsquoRourke and Jeon [1] compared data

collected from three mentioned analytical methods when itcame to the continuous pipeline under the Riley waversquospropagation Besides the model put forward by Takada [18]suggested that pipe is modelled in the form of a shell having alength of 60 D adjacent to the fault but it could be in theform of an beam element where the distance from the pipe tothe fault is almost 300meters and the extent of soil and pipeslipping and strains are insignificant (Figure 16) All thingsbeing equal soil surrounded the pipe is modelled using soilsprings according to the seismic designing regulation ofburied oil and gas pipes [19]

In 2004 Takada et al reported on a newmodel accordingto changes in boundary conditions ey suggest that thepipe should be modelled in the junction with the fault in theform of a shell element due to local strain and big trans-formations just the same as before Moreover each point ofthe shell element is connected to three soil springs in axiallateral and vertical directions Finally the relation betweenthe axial force (f ) and increased length ΔL which is regardedto boundary conditions for nonelastic springs is measuredas

F(ΔL)

3EAfs2

1113970U016ΔL

23 0ltΔLltU0 (4)

3EAfsΔL minus 14U0

1113874 1113875

1113970σy2A2Efs

+U04

(5)

where Yσ acts as pipersquos yield stress and elasticity modulus Ithas been suggested that tensile rupture local buckling andthimble buckling are among the most significant damage tocontinuous pipes while tensile and compression ruptures ofpipe joints as well as local bending were the most commondamage observed in apart pipeline [20] Concerning mod-elling of continuous pipes Halabian and Hokmabadi [21]stimulated faulting and wave propagation in the laboratoryof Isfahan Technological University Iran and adoptedequivalent boundary conditions put forward by Takadawhen it came to boundary conditions related to the end ofthe pipe so they conducted a parametric study on the be-haviour of buried pipelines

Equivalent boundary

Axial spring damper

Equivalent boundary

Lateral spring damper

Vertical spring damper

Figure 15 Apparent propagation of an R wave strain of the ground and curvature results

Shock and Vibration 7

Rofooei and Qorbani [19] assumed a vertical wavepropagation in order to conduct a parametric study oncontinuous pipes under earthquake loadingey stimulatedthe pipe and surrounding soil through springs according tothe ALA regulation using ANSIS software Considering datacollected from effects of pipe and soil geometric changes ontheir relative displacement they observed increase in relo-cation in the soil-pipe boundary due to decrease in soilaggregation

35 e Seismic Susceptibility Model concerning BuriedPipelines Hazussr2i is a guideline on estimating damage tostructures due to the earthquake which was developed byFEMA and the national institute of the US Architecture It iscomprised of ways to estimate the extent of earthquakedamage to various structures including lifelines Accord-ingly the guideline suggests that leakage tends to happenbecause of earthquake waves in which 80 depends uponmaximum earth velocity and 20 is a function of earthrsquospermanent transformations while it has been found thatpipe breakage proves to be due to earthrsquos big transformationsin which 20 and 80 depend upon PGA and PGDrespectively

Furthermore the method divides pipes into two groupsincluding frangible and flexible As a result susceptibility offlexible pipes decreases by 70 e likelihood of soil liq-uefaction has been directly entered to the Hazus modelwhich is assumed as the most significant factor on pipedisplacement e algorithm concerning susceptibility ofburied pipes under earthquake waves was found by ana-lysing experimental data collected from four earthquakes inthe US and two in Mexico en data were adjusted to theHazus method

e guideline divides pipes into small and big groups inorder to estimate time required for reconstructing pipelinesdamaged in earthquakes Accordingly the small group in-cludes pipes having a diameter of 20 inch or less while othersare put in the big group e method also estimates daysrequired for reconstruction of the water supply system efollowing assumptions suggest how to measure days forrepair the pipeline It takes an equipped four-man team forfour and eight hours to repair a leaky and a broken piperespectively It takes an equipped four-man team for six and

twelve hours to repair a leaky and a broken pipe respec-tively ere is a linear link between repair program andtime As a result the extent of repairs done on a pipelinewhich needs (a) days within (b) days with a fixed number ofworkers is measured ba (Table 2)

36eSusceptibility IndexVI In this method the weightedcoefficient is assumed as a factor covering pipe diameter cdconditions of the ground cg magnitude of the earthquakebased on the Mercalli intensity scale ci pipe passage throughthe fault cf soil liquefaction c1 and potential land slideoccurrence potential Tables 3ndash10 give information aboutweighted coefficients Susceptibility of each part in thewastewater system is achieved by giving weight to above-mentioned factors in different conditions and then multi-plying the value by the weighted coefficient of each factorConsidering data from Table 10 and based on values ob-tained from forgoing equation (6) susceptibility of thewastewater system is divided into three groups includinghigh medium and low It is worth mentioning thatweighted coefficients concerning each factor have been se-lected based on maximum recorded damage to the buriedpipeline in past earthquakes Table 5 gives information aboutweighted coefficient regarding conditions of the groundbased on different types of soil In addition Table 6 illus-trates magnitude of an earthquake as well as correspondentimproved intensity scale (MMI) in PGA

VI cd middot cp middot cf middot cg middot ci middot cl middot cs (6)

4 Numerical Simulation

A complete set is comprised of software hardware datamodels algorithms and human resources for collectingpreparing organizing storing updating processing andanalysing different types of local data Such a system aims tomanage and handle information collected from the referenceplace in order to make sensible decisions e data modelindicates transformation of the real world by observingrelated geometrical relations and descriptive information toa reasonable and digital oneemodel represents all objectsin the form of points lines or polygon However topologicaldata aim to extract relations between phenomena Existing

Base springs

Longitudinal soil springs not shown

Overburden or uplift springs

Initial position

Design thawsettlement

Figure 16 Finite-element model of a shell element in collision with the fault

8 Shock and Vibration

relations between phenomena in local data function as partand particle of some GIS analysing systems In the rastermodel the whole map is divided into a set of small andregular cells called pixel e raster format is actuallycomposed of an nlowastm array of pixels

e geographical information system (GIS) has recentlyattracted the attention of different engineering fields e

ability to interpret and analyse data in such systems andsoftware enables us to review multiple parameters andfactors affecting different analyses and achieve reliable re-sults Research has proved the applicability of GIS to analysedata and extract results in the field of water and wastewaterengineering In the current research the most well-knownsoftware package appertain to geographical informationArcGIS Desktop 101 has been used to analyse data For thepurpose of analysis first softwarersquos default data and geo-graphical tiers called GIS READY were prepared eprocess was comprised of improving designing mistakes andthen doing a georeferencing operation

Since most of data were in the form of paper maps theywere first scanned and then by taking the scale of data intoaccount data were turned into a numerical one Finally withregard to available data as well as type of analysis all datawere changed into a roster model based on their effectiveparameters (Figure 17)

Table 2 Hazus equations concerning the ratio of damage to a buried pipeline

Type of pipe e ratio of damage to a PGV pipe per kilometer e ratio of damage to a PGD pipe per kilometerFragile RR 00001lowastPGV225 RR prob lowastPGD056Flexible RR 03 lowast 00001 lowastPGV225 RR 03 lowast prob lowastPGD056PR is defined as the extent of damage to the pipe per kilometerPGV (cmsminus1)PGD (inch)

Table 3 Weighted coefficient for diameter of a pipe

Coefficient cd Pipe diameter (d)Dlt 75mm 1675mmlt dlt 150mm 10150mmlt dlt 250mm 09250mmlt dlt 450mm 07450mmlt dlt 1000mm 05dgt 1000mm 04

Table 4 Weighted coefficient for type of pipe

Type of the pipeline Coefficient (cp)Soft cast iron 03Cast iron 10Ceramic 3Asbestos 25Poly ethylene 01Concrete 2

Table 5 Weighted coefficient for conditions of the ground

Type of soil CoefficientType I 05Type II 1Type III 2Type IV 29

Table 6 Weighted coefficient for magnitude of the earthquake

Magnitude of the earthquake CoefficientMMIlt 8 10PGAlt 025G8ltMMIlt 9 21025GltPGAlt 045G9ltMMIlt 10 24045GltPGAlt 06G10ltMMIlt 11 3006GltPGAlt 09G11ltMMI 35PGAgt 09G

Table 7 Weighted coefficient for passage of the pipeline throughthe fault

Passage of the pipeline through a fault CoefficientNo passage 1One passage 2Multiple passages 24

Table 8 Weighted coefficient for soil liquefaction

Liquefaction Coefficient0ltPL1lt 5 15ltPLlt 15 2PLgt 15 24

Table 9 Weighted coefficient for the land slide potential CS

Potential of the land slide CoefficientNo danger 1Medium danger 2High danger 24

Table 10 Classification of the extent of seismic susceptibility of thewastewater system

Color Susceptibility level VI indexGreen Low 0ltVIlt 5Orange Medium 5ltVIlt 12Red High VIgt 12

Shock and Vibration 9

41 Statistical Population Gorgan a city in Golestan Iranwas selected in the current case study research It has beenthe first city in the province equipped with the wastewatersystem As the city experiences dozens of small earthquakesevery day it is worth studying susceptibility of the waste-water system to earthquake e wastewater system is124meters in length (Figure 18)

First maps developed in AutoCAD software pertinent tothe Gorgan wastewater system were collected in order toassess the extent of damage to the system due to earthquakesNext maps were turned into GIS data Both 2 and 10 percentdanger analysis maps were adjusted to aerial photos andthen corrected ones were entered into GIS software tomeasure the seismic susceptibility ratio under maximumland movement

42 Sampling Method and Sample Size In the current re-search two types of data including maps of seismic analysisand wastewater pipelinesrsquo code were used e former in-cludes curves aligned with velocity of potential approachesof the vertical element which are pertinent to a return periodof 75 years for 2 PGA and a return period of 475 years for10 PGA for an estimated 50 year service life

43 e Map of Selected Wastewater System e Gorganwater and wastewater organization has provided the re-searcher with given maps as well as a file containing pipe-linesrsquo codes (Figures 19 and 20) en the file entered intothe GIS software and improved

44 Data Analysis Research variables include characteris-tics of pipes as well as velocity of the earthquake which havebeen drawn by adjusting rough maps of earthquake velocityand the cityrsquos wastewater system (Figures 21 and 22)

5 Results and Discussion

Raw data were put into GIS software as input and twooutput data were obtained Figures 23 and 24 illustrate the

Iteratefeature

Select layerby location

Summarystatistics

Get fieldvalue

Calculatefield End

Figure 17 e algorithm determining the extent of damage observed under an earthquake wave in GIS

Figure 18 Geographical location of Gorgan

Figure 19 e organization map of the urban wastewater system

Diameter150200250300400500600700800

Figure 20 e map of Borujen wastewater system (diameter ofpipes)

033

031

Figure 21 e PGA10 map and Borujenrsquos wastewater system

10 Shock and Vibration

extent of damage to pipes using Hazus based on two dif-ferent earthquake velocities namely PGA 2 and PGA 10

Figures 25 and 26 give information about the extent ofdamage under two different earthquakes according to the VImethod

6 Conclusion

Comparing HAUS and VI methods suggests that the formergives more accurate and detailed data so it enables au-thorities to make better decisions for boosting and planningstructures and finding their susceptible points Moreover asthe method helps to find out the extent of damage structureswould suffer after occurrence of an earthquake recon-struction process would be done quickly and precisely

Considering the point that the region has always beenearthquake-prone reviewing data obtained frommaps showa high level of damage Maps are indicating the first pre-diction of the current research that is to say susceptibility ofthe wastewater system to occurrence of any earthquake so itfocuses on the necessity for replacing existent pipelines withmore resistant ones

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

049

052

Figure 22 e PGA2 map and wastewater system

0867840466ndash37318188373181886ndash6595797256595797252ndash94597756

9459775645ndash12323754

1232375405ndash151877321518773244ndash180517101805171083ndash20915689

2091568922ndash237796672377966762ndash26643646

Number of repair10

Figure 23 e total number of Hazus SR2 damage underPGA10

494688108017143028310733633443371853167709116841346914669157521636517644

Number of repair2value

Figure 24 e total number of Hazus SR2 damage under PGA2

Figure 25 e total number of damage under PGA2 accordingto the VI method

Figure 26 e total number of damage under PGA10 accordingto the VI method

Shock and Vibration 11

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T D OrsquoRourke and S S Jeon ldquoFactors affecting the earth-quake damage of water distribution systems in optimizingpost-earthquake lifeline system in optimizing post-life linesystem reliabilityrdquo in Proceedings of the Fifth US Conferenceon Lifeline Earthquake Engineering ASCE Seattle WC USA1999

[2] U Albayrak A Loai and M Morshid ldquoEvaluation of seismicperformance of steel lattice transmission towersrdquo Civil En-gineering Journal vol 6 no 10 pp 1ndash21 2020

[3] B Cai and M H Golestan ldquoTowards bayesian quantificationof permeability in micro-scale porous structuresrdquo e Da-tabase of Micro Networks vol 1 no 4 pp 1ndash13 2020

[4] H Shah and S Chu ldquoSeismic analysis of undergroundstructural elementsrdquo Journal of the Power Division vol 100no 1 pp 53ndash62 1974

[5] E C Goodling ldquoBuried pipingndashan analysis procedure up-daterdquo in Proceedings of the International Symposium onLifeline Earthquake Engineering vol 77 pp 225ndash237 ASMEPortland Oregon May 1983

[6] M Shinozuka and T Koike ldquoEstimation of structural strain inunderground lifeline pipesrdquo Lifeline Earthquake Engineering-Buried Pipeline Seismic Risk and Instrumentation vol 34pp 31ndash48 1979

[7] S Takada and K Tanabe ldquoree-dimensional seismic re-sponse analysis of buried continuous or jointed pipelinesrdquoJournal of Pressure Vessel Technology vol 109 no 1pp 80ndash87 1987

[8] S Takada A Carlo S Bo and X Wuhu Current State of theArts on Pipeline Earthquake Engineering in Japan eConstruction Engineering Research Foundation PuneMaharashtra India vol 1 1992

[9] L Dai D Wang T Wang Q Feng and X Yang ldquoAnalysisand comparison of long-distance pipeline failuresrdquo Journal ofPetroleum Engineering vol 2017 no 1 7 pages Article ID3174636 2017

[10] Y Yang S Yang Z Li et al ldquoAnalysis of hazard area ofdispersion caused by leakage from underground gas-storagecaverns in salt rockrdquo Advances in Civil Engineering vol 2020no 1 11 pages

[11] M Cubrinovski Geotechnical Reconnaissance of the 2010Darfield (New Zealand) Earthquake University of Canter-bury Christchurch New Zealand 2010

[12] Y Maruyama and F Yamazaki ldquoConstruction of fragilitycurve for water distribution pipes based on damage datasetsfrom recent earthquakes in Japanrdquo in Proceedings of the 9thUS National and 10th Canadian Conference on EarthquakeEngineering Toronto ON Canada July 2010

[13] J F Bird and J J Bommer ldquoEarthquake losses due to groundfailurerdquo Engineering Geology vol 75 no 2 pp 147ndash179 2004

[14] M Zare and S Wilkinson ldquoEarthquake damage in wastewatersystem and post earthquake repair methodslimitation andpractcerdquo in Proceedings of the Australian Earthquake Engi-neering Society Conference Novotel Bavossa Valley RwsortBarossa Valley South Australia November 2011

[15] R T Eguchi ldquoSeismic vulnerability models for undergroundpipesrdquo in Proceedings of the International Symposium onEarthquakeBehavior and Safety of Oil and Gas Storage

Facilities Buried Pipelines and Equipment American Societyof Mechanical Engineers (ASME) New York NY USAJanuary 1983

[16] N M Newmark ldquoSeismic design criteria for structures andfacilities Trans-Alaska pipeline systemrdquo in Proceedings of theUS National Conference on Earthquake Engineering Earth-quake Engineering Institute San Francisco CA USA June1975

[17] G Yeh ldquoSeismic analysis of slender buried beamsrdquo eBulletin of the Seismological Society of America vol 64o no 5pp 1551ndash1562 1974

[18] S Takada N Hassani and K Fukuda ldquoA new proposal forsimplified design of buried steel pipes crossing active faultsrdquoEarthquake Engineering amp Structural Dynamics vol 30 no 8pp 1243ndash1257 2001

[19] F R Rofooei and R Qorbani ldquoA parametric study on seismicbehavior of continuous buried pipeline due to wave propa-gationrdquo in Proceedings of the 14th World Conference onEarthquake Engineering Beijing China October 2008

[20] M Hosseini and S Jallili ldquoAssessment of the nonlineearbehavior of connection in water distribution networks fortheir seimic evaluationrdquo Procedia Engineering vol 14pp 2878ndash2883 2011

[21] A M Halabian and T Hokmabadi ldquoA new hybrid model forrigorous analysis of buried pipelines under general faultingaccounting for material and geometrical non-linearities withfocusing on corrugated HDPE pipelinesrdquo Soil Dynamics andEarthquake Engineering vol 115 pp 1ndash17 2018

12 Shock and Vibration

below is used to measure apparent wave velocity in thedirection of pipersquos axis

Cs - apparent cs

sin θ middot cos c (3)

Yeh [17] illustrated that maximum strain of the earth ismeasured by 45 θ c in given plates

34 Studying Seismic Behaviour of a Soil-Pipe System con-cerning Continuous Buried Pipelines A structure bearsbending or axial transformations after an earthquakeProviding satisfying plasticity in order to absorb transfor-mations due to earthquake without decrease in static loadingcapacity acts as an important design criterion Generallydeveloped axial strain throughout a continuous direct pipedepends upon such factors as shape of the earth transmittalwave length and soil-pipe interaction forces Althoughstrain of pipe and soil are assumed equal for small- tomedium-sized movements the same is not true for greatstrains because of existent slipping between soil and pipe Ithas been found to decrease pipe strain compared to that ofsoil Newmark [16] put forward a simple method to de-termine how the pipeline acts when earthquake waves arepropagated en other researchers such as Yeh revised it

Seismic movement of the earth which is defined as thehistory of velocity-time and velocity-displacement func-tions as a transmittal wave with fixed shape It suggests thattwo points along the propagation path simply shake by atime lag Inertia involved in small movement equations istoo small to be measured Later the assumption was studiedby many researchers and their works showed that it acts as areasonable engineering approximation It is assumed that norelative movement happens in the soil-pipe interaction andpipersquos strain equals to that of soil In addition OrsquoRourke andEl Hamadi developed an analytical method to estimatemaximum pipe strain

e method assumes that first axial strain in soil equalspipe strain arising from length friction between soil and pipeand second waves are propagated parallel to the axis of pipeIn a research study OrsquoRourke and Jeon [1] compared data

collected from three mentioned analytical methods when itcame to the continuous pipeline under the Riley waversquospropagation Besides the model put forward by Takada [18]suggested that pipe is modelled in the form of a shell having alength of 60 D adjacent to the fault but it could be in theform of an beam element where the distance from the pipe tothe fault is almost 300meters and the extent of soil and pipeslipping and strains are insignificant (Figure 16) All thingsbeing equal soil surrounded the pipe is modelled using soilsprings according to the seismic designing regulation ofburied oil and gas pipes [19]

In 2004 Takada et al reported on a newmodel accordingto changes in boundary conditions ey suggest that thepipe should be modelled in the junction with the fault in theform of a shell element due to local strain and big trans-formations just the same as before Moreover each point ofthe shell element is connected to three soil springs in axiallateral and vertical directions Finally the relation betweenthe axial force (f ) and increased length ΔL which is regardedto boundary conditions for nonelastic springs is measuredas

F(ΔL)

3EAfs2

1113970U016ΔL

23 0ltΔLltU0 (4)

3EAfsΔL minus 14U0

1113874 1113875

1113970σy2A2Efs

+U04

(5)

where Yσ acts as pipersquos yield stress and elasticity modulus Ithas been suggested that tensile rupture local buckling andthimble buckling are among the most significant damage tocontinuous pipes while tensile and compression ruptures ofpipe joints as well as local bending were the most commondamage observed in apart pipeline [20] Concerning mod-elling of continuous pipes Halabian and Hokmabadi [21]stimulated faulting and wave propagation in the laboratoryof Isfahan Technological University Iran and adoptedequivalent boundary conditions put forward by Takadawhen it came to boundary conditions related to the end ofthe pipe so they conducted a parametric study on the be-haviour of buried pipelines

Equivalent boundary

Axial spring damper

Equivalent boundary

Lateral spring damper

Vertical spring damper

Figure 15 Apparent propagation of an R wave strain of the ground and curvature results

Shock and Vibration 7

Rofooei and Qorbani [19] assumed a vertical wavepropagation in order to conduct a parametric study oncontinuous pipes under earthquake loadingey stimulatedthe pipe and surrounding soil through springs according tothe ALA regulation using ANSIS software Considering datacollected from effects of pipe and soil geometric changes ontheir relative displacement they observed increase in relo-cation in the soil-pipe boundary due to decrease in soilaggregation

35 e Seismic Susceptibility Model concerning BuriedPipelines Hazussr2i is a guideline on estimating damage tostructures due to the earthquake which was developed byFEMA and the national institute of the US Architecture It iscomprised of ways to estimate the extent of earthquakedamage to various structures including lifelines Accord-ingly the guideline suggests that leakage tends to happenbecause of earthquake waves in which 80 depends uponmaximum earth velocity and 20 is a function of earthrsquospermanent transformations while it has been found thatpipe breakage proves to be due to earthrsquos big transformationsin which 20 and 80 depend upon PGA and PGDrespectively

Furthermore the method divides pipes into two groupsincluding frangible and flexible As a result susceptibility offlexible pipes decreases by 70 e likelihood of soil liq-uefaction has been directly entered to the Hazus modelwhich is assumed as the most significant factor on pipedisplacement e algorithm concerning susceptibility ofburied pipes under earthquake waves was found by ana-lysing experimental data collected from four earthquakes inthe US and two in Mexico en data were adjusted to theHazus method

e guideline divides pipes into small and big groups inorder to estimate time required for reconstructing pipelinesdamaged in earthquakes Accordingly the small group in-cludes pipes having a diameter of 20 inch or less while othersare put in the big group e method also estimates daysrequired for reconstruction of the water supply system efollowing assumptions suggest how to measure days forrepair the pipeline It takes an equipped four-man team forfour and eight hours to repair a leaky and a broken piperespectively It takes an equipped four-man team for six and

twelve hours to repair a leaky and a broken pipe respec-tively ere is a linear link between repair program andtime As a result the extent of repairs done on a pipelinewhich needs (a) days within (b) days with a fixed number ofworkers is measured ba (Table 2)

36eSusceptibility IndexVI In this method the weightedcoefficient is assumed as a factor covering pipe diameter cdconditions of the ground cg magnitude of the earthquakebased on the Mercalli intensity scale ci pipe passage throughthe fault cf soil liquefaction c1 and potential land slideoccurrence potential Tables 3ndash10 give information aboutweighted coefficients Susceptibility of each part in thewastewater system is achieved by giving weight to above-mentioned factors in different conditions and then multi-plying the value by the weighted coefficient of each factorConsidering data from Table 10 and based on values ob-tained from forgoing equation (6) susceptibility of thewastewater system is divided into three groups includinghigh medium and low It is worth mentioning thatweighted coefficients concerning each factor have been se-lected based on maximum recorded damage to the buriedpipeline in past earthquakes Table 5 gives information aboutweighted coefficient regarding conditions of the groundbased on different types of soil In addition Table 6 illus-trates magnitude of an earthquake as well as correspondentimproved intensity scale (MMI) in PGA

VI cd middot cp middot cf middot cg middot ci middot cl middot cs (6)

4 Numerical Simulation

A complete set is comprised of software hardware datamodels algorithms and human resources for collectingpreparing organizing storing updating processing andanalysing different types of local data Such a system aims tomanage and handle information collected from the referenceplace in order to make sensible decisions e data modelindicates transformation of the real world by observingrelated geometrical relations and descriptive information toa reasonable and digital oneemodel represents all objectsin the form of points lines or polygon However topologicaldata aim to extract relations between phenomena Existing

Base springs

Longitudinal soil springs not shown

Overburden or uplift springs

Initial position

Design thawsettlement

Figure 16 Finite-element model of a shell element in collision with the fault

8 Shock and Vibration

relations between phenomena in local data function as partand particle of some GIS analysing systems In the rastermodel the whole map is divided into a set of small andregular cells called pixel e raster format is actuallycomposed of an nlowastm array of pixels

e geographical information system (GIS) has recentlyattracted the attention of different engineering fields e

ability to interpret and analyse data in such systems andsoftware enables us to review multiple parameters andfactors affecting different analyses and achieve reliable re-sults Research has proved the applicability of GIS to analysedata and extract results in the field of water and wastewaterengineering In the current research the most well-knownsoftware package appertain to geographical informationArcGIS Desktop 101 has been used to analyse data For thepurpose of analysis first softwarersquos default data and geo-graphical tiers called GIS READY were prepared eprocess was comprised of improving designing mistakes andthen doing a georeferencing operation

Since most of data were in the form of paper maps theywere first scanned and then by taking the scale of data intoaccount data were turned into a numerical one Finally withregard to available data as well as type of analysis all datawere changed into a roster model based on their effectiveparameters (Figure 17)

Table 2 Hazus equations concerning the ratio of damage to a buried pipeline

Type of pipe e ratio of damage to a PGV pipe per kilometer e ratio of damage to a PGD pipe per kilometerFragile RR 00001lowastPGV225 RR prob lowastPGD056Flexible RR 03 lowast 00001 lowastPGV225 RR 03 lowast prob lowastPGD056PR is defined as the extent of damage to the pipe per kilometerPGV (cmsminus1)PGD (inch)

Table 3 Weighted coefficient for diameter of a pipe

Coefficient cd Pipe diameter (d)Dlt 75mm 1675mmlt dlt 150mm 10150mmlt dlt 250mm 09250mmlt dlt 450mm 07450mmlt dlt 1000mm 05dgt 1000mm 04

Table 4 Weighted coefficient for type of pipe

Type of the pipeline Coefficient (cp)Soft cast iron 03Cast iron 10Ceramic 3Asbestos 25Poly ethylene 01Concrete 2

Table 5 Weighted coefficient for conditions of the ground

Type of soil CoefficientType I 05Type II 1Type III 2Type IV 29

Table 6 Weighted coefficient for magnitude of the earthquake

Magnitude of the earthquake CoefficientMMIlt 8 10PGAlt 025G8ltMMIlt 9 21025GltPGAlt 045G9ltMMIlt 10 24045GltPGAlt 06G10ltMMIlt 11 3006GltPGAlt 09G11ltMMI 35PGAgt 09G

Table 7 Weighted coefficient for passage of the pipeline throughthe fault

Passage of the pipeline through a fault CoefficientNo passage 1One passage 2Multiple passages 24

Table 8 Weighted coefficient for soil liquefaction

Liquefaction Coefficient0ltPL1lt 5 15ltPLlt 15 2PLgt 15 24

Table 9 Weighted coefficient for the land slide potential CS

Potential of the land slide CoefficientNo danger 1Medium danger 2High danger 24

Table 10 Classification of the extent of seismic susceptibility of thewastewater system

Color Susceptibility level VI indexGreen Low 0ltVIlt 5Orange Medium 5ltVIlt 12Red High VIgt 12

Shock and Vibration 9

41 Statistical Population Gorgan a city in Golestan Iranwas selected in the current case study research It has beenthe first city in the province equipped with the wastewatersystem As the city experiences dozens of small earthquakesevery day it is worth studying susceptibility of the waste-water system to earthquake e wastewater system is124meters in length (Figure 18)

First maps developed in AutoCAD software pertinent tothe Gorgan wastewater system were collected in order toassess the extent of damage to the system due to earthquakesNext maps were turned into GIS data Both 2 and 10 percentdanger analysis maps were adjusted to aerial photos andthen corrected ones were entered into GIS software tomeasure the seismic susceptibility ratio under maximumland movement

42 Sampling Method and Sample Size In the current re-search two types of data including maps of seismic analysisand wastewater pipelinesrsquo code were used e former in-cludes curves aligned with velocity of potential approachesof the vertical element which are pertinent to a return periodof 75 years for 2 PGA and a return period of 475 years for10 PGA for an estimated 50 year service life

43 e Map of Selected Wastewater System e Gorganwater and wastewater organization has provided the re-searcher with given maps as well as a file containing pipe-linesrsquo codes (Figures 19 and 20) en the file entered intothe GIS software and improved

44 Data Analysis Research variables include characteris-tics of pipes as well as velocity of the earthquake which havebeen drawn by adjusting rough maps of earthquake velocityand the cityrsquos wastewater system (Figures 21 and 22)

5 Results and Discussion

Raw data were put into GIS software as input and twooutput data were obtained Figures 23 and 24 illustrate the

Iteratefeature

Select layerby location

Summarystatistics

Get fieldvalue

Calculatefield End

Figure 17 e algorithm determining the extent of damage observed under an earthquake wave in GIS

Figure 18 Geographical location of Gorgan

Figure 19 e organization map of the urban wastewater system

Diameter150200250300400500600700800

Figure 20 e map of Borujen wastewater system (diameter ofpipes)

033

031

Figure 21 e PGA10 map and Borujenrsquos wastewater system

10 Shock and Vibration

extent of damage to pipes using Hazus based on two dif-ferent earthquake velocities namely PGA 2 and PGA 10

Figures 25 and 26 give information about the extent ofdamage under two different earthquakes according to the VImethod

6 Conclusion

Comparing HAUS and VI methods suggests that the formergives more accurate and detailed data so it enables au-thorities to make better decisions for boosting and planningstructures and finding their susceptible points Moreover asthe method helps to find out the extent of damage structureswould suffer after occurrence of an earthquake recon-struction process would be done quickly and precisely

Considering the point that the region has always beenearthquake-prone reviewing data obtained frommaps showa high level of damage Maps are indicating the first pre-diction of the current research that is to say susceptibility ofthe wastewater system to occurrence of any earthquake so itfocuses on the necessity for replacing existent pipelines withmore resistant ones

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

049

052

Figure 22 e PGA2 map and wastewater system

0867840466ndash37318188373181886ndash6595797256595797252ndash94597756

9459775645ndash12323754

1232375405ndash151877321518773244ndash180517101805171083ndash20915689

2091568922ndash237796672377966762ndash26643646

Number of repair10

Figure 23 e total number of Hazus SR2 damage underPGA10

494688108017143028310733633443371853167709116841346914669157521636517644

Number of repair2value

Figure 24 e total number of Hazus SR2 damage under PGA2

Figure 25 e total number of damage under PGA2 accordingto the VI method

Figure 26 e total number of damage under PGA10 accordingto the VI method

Shock and Vibration 11

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T D OrsquoRourke and S S Jeon ldquoFactors affecting the earth-quake damage of water distribution systems in optimizingpost-earthquake lifeline system in optimizing post-life linesystem reliabilityrdquo in Proceedings of the Fifth US Conferenceon Lifeline Earthquake Engineering ASCE Seattle WC USA1999

[2] U Albayrak A Loai and M Morshid ldquoEvaluation of seismicperformance of steel lattice transmission towersrdquo Civil En-gineering Journal vol 6 no 10 pp 1ndash21 2020

[3] B Cai and M H Golestan ldquoTowards bayesian quantificationof permeability in micro-scale porous structuresrdquo e Da-tabase of Micro Networks vol 1 no 4 pp 1ndash13 2020

[4] H Shah and S Chu ldquoSeismic analysis of undergroundstructural elementsrdquo Journal of the Power Division vol 100no 1 pp 53ndash62 1974

[5] E C Goodling ldquoBuried pipingndashan analysis procedure up-daterdquo in Proceedings of the International Symposium onLifeline Earthquake Engineering vol 77 pp 225ndash237 ASMEPortland Oregon May 1983

[6] M Shinozuka and T Koike ldquoEstimation of structural strain inunderground lifeline pipesrdquo Lifeline Earthquake Engineering-Buried Pipeline Seismic Risk and Instrumentation vol 34pp 31ndash48 1979

[7] S Takada and K Tanabe ldquoree-dimensional seismic re-sponse analysis of buried continuous or jointed pipelinesrdquoJournal of Pressure Vessel Technology vol 109 no 1pp 80ndash87 1987

[8] S Takada A Carlo S Bo and X Wuhu Current State of theArts on Pipeline Earthquake Engineering in Japan eConstruction Engineering Research Foundation PuneMaharashtra India vol 1 1992

[9] L Dai D Wang T Wang Q Feng and X Yang ldquoAnalysisand comparison of long-distance pipeline failuresrdquo Journal ofPetroleum Engineering vol 2017 no 1 7 pages Article ID3174636 2017

[10] Y Yang S Yang Z Li et al ldquoAnalysis of hazard area ofdispersion caused by leakage from underground gas-storagecaverns in salt rockrdquo Advances in Civil Engineering vol 2020no 1 11 pages

[11] M Cubrinovski Geotechnical Reconnaissance of the 2010Darfield (New Zealand) Earthquake University of Canter-bury Christchurch New Zealand 2010

[12] Y Maruyama and F Yamazaki ldquoConstruction of fragilitycurve for water distribution pipes based on damage datasetsfrom recent earthquakes in Japanrdquo in Proceedings of the 9thUS National and 10th Canadian Conference on EarthquakeEngineering Toronto ON Canada July 2010

[13] J F Bird and J J Bommer ldquoEarthquake losses due to groundfailurerdquo Engineering Geology vol 75 no 2 pp 147ndash179 2004

[14] M Zare and S Wilkinson ldquoEarthquake damage in wastewatersystem and post earthquake repair methodslimitation andpractcerdquo in Proceedings of the Australian Earthquake Engi-neering Society Conference Novotel Bavossa Valley RwsortBarossa Valley South Australia November 2011

[15] R T Eguchi ldquoSeismic vulnerability models for undergroundpipesrdquo in Proceedings of the International Symposium onEarthquakeBehavior and Safety of Oil and Gas Storage

Facilities Buried Pipelines and Equipment American Societyof Mechanical Engineers (ASME) New York NY USAJanuary 1983

[16] N M Newmark ldquoSeismic design criteria for structures andfacilities Trans-Alaska pipeline systemrdquo in Proceedings of theUS National Conference on Earthquake Engineering Earth-quake Engineering Institute San Francisco CA USA June1975

[17] G Yeh ldquoSeismic analysis of slender buried beamsrdquo eBulletin of the Seismological Society of America vol 64o no 5pp 1551ndash1562 1974

[18] S Takada N Hassani and K Fukuda ldquoA new proposal forsimplified design of buried steel pipes crossing active faultsrdquoEarthquake Engineering amp Structural Dynamics vol 30 no 8pp 1243ndash1257 2001

[19] F R Rofooei and R Qorbani ldquoA parametric study on seismicbehavior of continuous buried pipeline due to wave propa-gationrdquo in Proceedings of the 14th World Conference onEarthquake Engineering Beijing China October 2008

[20] M Hosseini and S Jallili ldquoAssessment of the nonlineearbehavior of connection in water distribution networks fortheir seimic evaluationrdquo Procedia Engineering vol 14pp 2878ndash2883 2011

[21] A M Halabian and T Hokmabadi ldquoA new hybrid model forrigorous analysis of buried pipelines under general faultingaccounting for material and geometrical non-linearities withfocusing on corrugated HDPE pipelinesrdquo Soil Dynamics andEarthquake Engineering vol 115 pp 1ndash17 2018

12 Shock and Vibration

Rofooei and Qorbani [19] assumed a vertical wavepropagation in order to conduct a parametric study oncontinuous pipes under earthquake loadingey stimulatedthe pipe and surrounding soil through springs according tothe ALA regulation using ANSIS software Considering datacollected from effects of pipe and soil geometric changes ontheir relative displacement they observed increase in relo-cation in the soil-pipe boundary due to decrease in soilaggregation

35 e Seismic Susceptibility Model concerning BuriedPipelines Hazussr2i is a guideline on estimating damage tostructures due to the earthquake which was developed byFEMA and the national institute of the US Architecture It iscomprised of ways to estimate the extent of earthquakedamage to various structures including lifelines Accord-ingly the guideline suggests that leakage tends to happenbecause of earthquake waves in which 80 depends uponmaximum earth velocity and 20 is a function of earthrsquospermanent transformations while it has been found thatpipe breakage proves to be due to earthrsquos big transformationsin which 20 and 80 depend upon PGA and PGDrespectively

Furthermore the method divides pipes into two groupsincluding frangible and flexible As a result susceptibility offlexible pipes decreases by 70 e likelihood of soil liq-uefaction has been directly entered to the Hazus modelwhich is assumed as the most significant factor on pipedisplacement e algorithm concerning susceptibility ofburied pipes under earthquake waves was found by ana-lysing experimental data collected from four earthquakes inthe US and two in Mexico en data were adjusted to theHazus method

e guideline divides pipes into small and big groups inorder to estimate time required for reconstructing pipelinesdamaged in earthquakes Accordingly the small group in-cludes pipes having a diameter of 20 inch or less while othersare put in the big group e method also estimates daysrequired for reconstruction of the water supply system efollowing assumptions suggest how to measure days forrepair the pipeline It takes an equipped four-man team forfour and eight hours to repair a leaky and a broken piperespectively It takes an equipped four-man team for six and

twelve hours to repair a leaky and a broken pipe respec-tively ere is a linear link between repair program andtime As a result the extent of repairs done on a pipelinewhich needs (a) days within (b) days with a fixed number ofworkers is measured ba (Table 2)

36eSusceptibility IndexVI In this method the weightedcoefficient is assumed as a factor covering pipe diameter cdconditions of the ground cg magnitude of the earthquakebased on the Mercalli intensity scale ci pipe passage throughthe fault cf soil liquefaction c1 and potential land slideoccurrence potential Tables 3ndash10 give information aboutweighted coefficients Susceptibility of each part in thewastewater system is achieved by giving weight to above-mentioned factors in different conditions and then multi-plying the value by the weighted coefficient of each factorConsidering data from Table 10 and based on values ob-tained from forgoing equation (6) susceptibility of thewastewater system is divided into three groups includinghigh medium and low It is worth mentioning thatweighted coefficients concerning each factor have been se-lected based on maximum recorded damage to the buriedpipeline in past earthquakes Table 5 gives information aboutweighted coefficient regarding conditions of the groundbased on different types of soil In addition Table 6 illus-trates magnitude of an earthquake as well as correspondentimproved intensity scale (MMI) in PGA

VI cd middot cp middot cf middot cg middot ci middot cl middot cs (6)

4 Numerical Simulation

A complete set is comprised of software hardware datamodels algorithms and human resources for collectingpreparing organizing storing updating processing andanalysing different types of local data Such a system aims tomanage and handle information collected from the referenceplace in order to make sensible decisions e data modelindicates transformation of the real world by observingrelated geometrical relations and descriptive information toa reasonable and digital oneemodel represents all objectsin the form of points lines or polygon However topologicaldata aim to extract relations between phenomena Existing

Base springs

Longitudinal soil springs not shown

Overburden or uplift springs

Initial position

Design thawsettlement

Figure 16 Finite-element model of a shell element in collision with the fault

8 Shock and Vibration

relations between phenomena in local data function as partand particle of some GIS analysing systems In the rastermodel the whole map is divided into a set of small andregular cells called pixel e raster format is actuallycomposed of an nlowastm array of pixels

e geographical information system (GIS) has recentlyattracted the attention of different engineering fields e

ability to interpret and analyse data in such systems andsoftware enables us to review multiple parameters andfactors affecting different analyses and achieve reliable re-sults Research has proved the applicability of GIS to analysedata and extract results in the field of water and wastewaterengineering In the current research the most well-knownsoftware package appertain to geographical informationArcGIS Desktop 101 has been used to analyse data For thepurpose of analysis first softwarersquos default data and geo-graphical tiers called GIS READY were prepared eprocess was comprised of improving designing mistakes andthen doing a georeferencing operation

Since most of data were in the form of paper maps theywere first scanned and then by taking the scale of data intoaccount data were turned into a numerical one Finally withregard to available data as well as type of analysis all datawere changed into a roster model based on their effectiveparameters (Figure 17)

Table 2 Hazus equations concerning the ratio of damage to a buried pipeline

Type of pipe e ratio of damage to a PGV pipe per kilometer e ratio of damage to a PGD pipe per kilometerFragile RR 00001lowastPGV225 RR prob lowastPGD056Flexible RR 03 lowast 00001 lowastPGV225 RR 03 lowast prob lowastPGD056PR is defined as the extent of damage to the pipe per kilometerPGV (cmsminus1)PGD (inch)

Table 3 Weighted coefficient for diameter of a pipe

Coefficient cd Pipe diameter (d)Dlt 75mm 1675mmlt dlt 150mm 10150mmlt dlt 250mm 09250mmlt dlt 450mm 07450mmlt dlt 1000mm 05dgt 1000mm 04

Table 4 Weighted coefficient for type of pipe

Type of the pipeline Coefficient (cp)Soft cast iron 03Cast iron 10Ceramic 3Asbestos 25Poly ethylene 01Concrete 2

Table 5 Weighted coefficient for conditions of the ground

Type of soil CoefficientType I 05Type II 1Type III 2Type IV 29

Table 6 Weighted coefficient for magnitude of the earthquake

Magnitude of the earthquake CoefficientMMIlt 8 10PGAlt 025G8ltMMIlt 9 21025GltPGAlt 045G9ltMMIlt 10 24045GltPGAlt 06G10ltMMIlt 11 3006GltPGAlt 09G11ltMMI 35PGAgt 09G

Table 7 Weighted coefficient for passage of the pipeline throughthe fault

Passage of the pipeline through a fault CoefficientNo passage 1One passage 2Multiple passages 24

Table 8 Weighted coefficient for soil liquefaction

Liquefaction Coefficient0ltPL1lt 5 15ltPLlt 15 2PLgt 15 24

Table 9 Weighted coefficient for the land slide potential CS

Potential of the land slide CoefficientNo danger 1Medium danger 2High danger 24

Table 10 Classification of the extent of seismic susceptibility of thewastewater system

Color Susceptibility level VI indexGreen Low 0ltVIlt 5Orange Medium 5ltVIlt 12Red High VIgt 12

Shock and Vibration 9

41 Statistical Population Gorgan a city in Golestan Iranwas selected in the current case study research It has beenthe first city in the province equipped with the wastewatersystem As the city experiences dozens of small earthquakesevery day it is worth studying susceptibility of the waste-water system to earthquake e wastewater system is124meters in length (Figure 18)

First maps developed in AutoCAD software pertinent tothe Gorgan wastewater system were collected in order toassess the extent of damage to the system due to earthquakesNext maps were turned into GIS data Both 2 and 10 percentdanger analysis maps were adjusted to aerial photos andthen corrected ones were entered into GIS software tomeasure the seismic susceptibility ratio under maximumland movement

42 Sampling Method and Sample Size In the current re-search two types of data including maps of seismic analysisand wastewater pipelinesrsquo code were used e former in-cludes curves aligned with velocity of potential approachesof the vertical element which are pertinent to a return periodof 75 years for 2 PGA and a return period of 475 years for10 PGA for an estimated 50 year service life

43 e Map of Selected Wastewater System e Gorganwater and wastewater organization has provided the re-searcher with given maps as well as a file containing pipe-linesrsquo codes (Figures 19 and 20) en the file entered intothe GIS software and improved

44 Data Analysis Research variables include characteris-tics of pipes as well as velocity of the earthquake which havebeen drawn by adjusting rough maps of earthquake velocityand the cityrsquos wastewater system (Figures 21 and 22)

5 Results and Discussion

Raw data were put into GIS software as input and twooutput data were obtained Figures 23 and 24 illustrate the

Iteratefeature

Select layerby location

Summarystatistics

Get fieldvalue

Calculatefield End

Figure 17 e algorithm determining the extent of damage observed under an earthquake wave in GIS

Figure 18 Geographical location of Gorgan

Figure 19 e organization map of the urban wastewater system

Diameter150200250300400500600700800

Figure 20 e map of Borujen wastewater system (diameter ofpipes)

033

031

Figure 21 e PGA10 map and Borujenrsquos wastewater system

10 Shock and Vibration

extent of damage to pipes using Hazus based on two dif-ferent earthquake velocities namely PGA 2 and PGA 10

Figures 25 and 26 give information about the extent ofdamage under two different earthquakes according to the VImethod

6 Conclusion

Comparing HAUS and VI methods suggests that the formergives more accurate and detailed data so it enables au-thorities to make better decisions for boosting and planningstructures and finding their susceptible points Moreover asthe method helps to find out the extent of damage structureswould suffer after occurrence of an earthquake recon-struction process would be done quickly and precisely

Considering the point that the region has always beenearthquake-prone reviewing data obtained frommaps showa high level of damage Maps are indicating the first pre-diction of the current research that is to say susceptibility ofthe wastewater system to occurrence of any earthquake so itfocuses on the necessity for replacing existent pipelines withmore resistant ones

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

049

052

Figure 22 e PGA2 map and wastewater system

0867840466ndash37318188373181886ndash6595797256595797252ndash94597756

9459775645ndash12323754

1232375405ndash151877321518773244ndash180517101805171083ndash20915689

2091568922ndash237796672377966762ndash26643646

Number of repair10

Figure 23 e total number of Hazus SR2 damage underPGA10

494688108017143028310733633443371853167709116841346914669157521636517644

Number of repair2value

Figure 24 e total number of Hazus SR2 damage under PGA2

Figure 25 e total number of damage under PGA2 accordingto the VI method

Figure 26 e total number of damage under PGA10 accordingto the VI method

Shock and Vibration 11

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T D OrsquoRourke and S S Jeon ldquoFactors affecting the earth-quake damage of water distribution systems in optimizingpost-earthquake lifeline system in optimizing post-life linesystem reliabilityrdquo in Proceedings of the Fifth US Conferenceon Lifeline Earthquake Engineering ASCE Seattle WC USA1999

[2] U Albayrak A Loai and M Morshid ldquoEvaluation of seismicperformance of steel lattice transmission towersrdquo Civil En-gineering Journal vol 6 no 10 pp 1ndash21 2020

[3] B Cai and M H Golestan ldquoTowards bayesian quantificationof permeability in micro-scale porous structuresrdquo e Da-tabase of Micro Networks vol 1 no 4 pp 1ndash13 2020

[4] H Shah and S Chu ldquoSeismic analysis of undergroundstructural elementsrdquo Journal of the Power Division vol 100no 1 pp 53ndash62 1974

[5] E C Goodling ldquoBuried pipingndashan analysis procedure up-daterdquo in Proceedings of the International Symposium onLifeline Earthquake Engineering vol 77 pp 225ndash237 ASMEPortland Oregon May 1983

[6] M Shinozuka and T Koike ldquoEstimation of structural strain inunderground lifeline pipesrdquo Lifeline Earthquake Engineering-Buried Pipeline Seismic Risk and Instrumentation vol 34pp 31ndash48 1979

[7] S Takada and K Tanabe ldquoree-dimensional seismic re-sponse analysis of buried continuous or jointed pipelinesrdquoJournal of Pressure Vessel Technology vol 109 no 1pp 80ndash87 1987

[8] S Takada A Carlo S Bo and X Wuhu Current State of theArts on Pipeline Earthquake Engineering in Japan eConstruction Engineering Research Foundation PuneMaharashtra India vol 1 1992

[9] L Dai D Wang T Wang Q Feng and X Yang ldquoAnalysisand comparison of long-distance pipeline failuresrdquo Journal ofPetroleum Engineering vol 2017 no 1 7 pages Article ID3174636 2017

[10] Y Yang S Yang Z Li et al ldquoAnalysis of hazard area ofdispersion caused by leakage from underground gas-storagecaverns in salt rockrdquo Advances in Civil Engineering vol 2020no 1 11 pages

[11] M Cubrinovski Geotechnical Reconnaissance of the 2010Darfield (New Zealand) Earthquake University of Canter-bury Christchurch New Zealand 2010

[12] Y Maruyama and F Yamazaki ldquoConstruction of fragilitycurve for water distribution pipes based on damage datasetsfrom recent earthquakes in Japanrdquo in Proceedings of the 9thUS National and 10th Canadian Conference on EarthquakeEngineering Toronto ON Canada July 2010

[13] J F Bird and J J Bommer ldquoEarthquake losses due to groundfailurerdquo Engineering Geology vol 75 no 2 pp 147ndash179 2004

[14] M Zare and S Wilkinson ldquoEarthquake damage in wastewatersystem and post earthquake repair methodslimitation andpractcerdquo in Proceedings of the Australian Earthquake Engi-neering Society Conference Novotel Bavossa Valley RwsortBarossa Valley South Australia November 2011

[15] R T Eguchi ldquoSeismic vulnerability models for undergroundpipesrdquo in Proceedings of the International Symposium onEarthquakeBehavior and Safety of Oil and Gas Storage

Facilities Buried Pipelines and Equipment American Societyof Mechanical Engineers (ASME) New York NY USAJanuary 1983

[16] N M Newmark ldquoSeismic design criteria for structures andfacilities Trans-Alaska pipeline systemrdquo in Proceedings of theUS National Conference on Earthquake Engineering Earth-quake Engineering Institute San Francisco CA USA June1975

[17] G Yeh ldquoSeismic analysis of slender buried beamsrdquo eBulletin of the Seismological Society of America vol 64o no 5pp 1551ndash1562 1974

[18] S Takada N Hassani and K Fukuda ldquoA new proposal forsimplified design of buried steel pipes crossing active faultsrdquoEarthquake Engineering amp Structural Dynamics vol 30 no 8pp 1243ndash1257 2001

[19] F R Rofooei and R Qorbani ldquoA parametric study on seismicbehavior of continuous buried pipeline due to wave propa-gationrdquo in Proceedings of the 14th World Conference onEarthquake Engineering Beijing China October 2008

[20] M Hosseini and S Jallili ldquoAssessment of the nonlineearbehavior of connection in water distribution networks fortheir seimic evaluationrdquo Procedia Engineering vol 14pp 2878ndash2883 2011

[21] A M Halabian and T Hokmabadi ldquoA new hybrid model forrigorous analysis of buried pipelines under general faultingaccounting for material and geometrical non-linearities withfocusing on corrugated HDPE pipelinesrdquo Soil Dynamics andEarthquake Engineering vol 115 pp 1ndash17 2018

12 Shock and Vibration

relations between phenomena in local data function as partand particle of some GIS analysing systems In the rastermodel the whole map is divided into a set of small andregular cells called pixel e raster format is actuallycomposed of an nlowastm array of pixels

e geographical information system (GIS) has recentlyattracted the attention of different engineering fields e

ability to interpret and analyse data in such systems andsoftware enables us to review multiple parameters andfactors affecting different analyses and achieve reliable re-sults Research has proved the applicability of GIS to analysedata and extract results in the field of water and wastewaterengineering In the current research the most well-knownsoftware package appertain to geographical informationArcGIS Desktop 101 has been used to analyse data For thepurpose of analysis first softwarersquos default data and geo-graphical tiers called GIS READY were prepared eprocess was comprised of improving designing mistakes andthen doing a georeferencing operation

Since most of data were in the form of paper maps theywere first scanned and then by taking the scale of data intoaccount data were turned into a numerical one Finally withregard to available data as well as type of analysis all datawere changed into a roster model based on their effectiveparameters (Figure 17)

Table 2 Hazus equations concerning the ratio of damage to a buried pipeline

Type of pipe e ratio of damage to a PGV pipe per kilometer e ratio of damage to a PGD pipe per kilometerFragile RR 00001lowastPGV225 RR prob lowastPGD056Flexible RR 03 lowast 00001 lowastPGV225 RR 03 lowast prob lowastPGD056PR is defined as the extent of damage to the pipe per kilometerPGV (cmsminus1)PGD (inch)

Table 3 Weighted coefficient for diameter of a pipe

Coefficient cd Pipe diameter (d)Dlt 75mm 1675mmlt dlt 150mm 10150mmlt dlt 250mm 09250mmlt dlt 450mm 07450mmlt dlt 1000mm 05dgt 1000mm 04

Table 4 Weighted coefficient for type of pipe

Type of the pipeline Coefficient (cp)Soft cast iron 03Cast iron 10Ceramic 3Asbestos 25Poly ethylene 01Concrete 2

Table 5 Weighted coefficient for conditions of the ground

Type of soil CoefficientType I 05Type II 1Type III 2Type IV 29

Table 6 Weighted coefficient for magnitude of the earthquake

Magnitude of the earthquake CoefficientMMIlt 8 10PGAlt 025G8ltMMIlt 9 21025GltPGAlt 045G9ltMMIlt 10 24045GltPGAlt 06G10ltMMIlt 11 3006GltPGAlt 09G11ltMMI 35PGAgt 09G

Table 7 Weighted coefficient for passage of the pipeline throughthe fault

Passage of the pipeline through a fault CoefficientNo passage 1One passage 2Multiple passages 24

Table 8 Weighted coefficient for soil liquefaction

Liquefaction Coefficient0ltPL1lt 5 15ltPLlt 15 2PLgt 15 24

Table 9 Weighted coefficient for the land slide potential CS

Potential of the land slide CoefficientNo danger 1Medium danger 2High danger 24

Table 10 Classification of the extent of seismic susceptibility of thewastewater system

Color Susceptibility level VI indexGreen Low 0ltVIlt 5Orange Medium 5ltVIlt 12Red High VIgt 12

Shock and Vibration 9

41 Statistical Population Gorgan a city in Golestan Iranwas selected in the current case study research It has beenthe first city in the province equipped with the wastewatersystem As the city experiences dozens of small earthquakesevery day it is worth studying susceptibility of the waste-water system to earthquake e wastewater system is124meters in length (Figure 18)

First maps developed in AutoCAD software pertinent tothe Gorgan wastewater system were collected in order toassess the extent of damage to the system due to earthquakesNext maps were turned into GIS data Both 2 and 10 percentdanger analysis maps were adjusted to aerial photos andthen corrected ones were entered into GIS software tomeasure the seismic susceptibility ratio under maximumland movement

42 Sampling Method and Sample Size In the current re-search two types of data including maps of seismic analysisand wastewater pipelinesrsquo code were used e former in-cludes curves aligned with velocity of potential approachesof the vertical element which are pertinent to a return periodof 75 years for 2 PGA and a return period of 475 years for10 PGA for an estimated 50 year service life

43 e Map of Selected Wastewater System e Gorganwater and wastewater organization has provided the re-searcher with given maps as well as a file containing pipe-linesrsquo codes (Figures 19 and 20) en the file entered intothe GIS software and improved

44 Data Analysis Research variables include characteris-tics of pipes as well as velocity of the earthquake which havebeen drawn by adjusting rough maps of earthquake velocityand the cityrsquos wastewater system (Figures 21 and 22)

5 Results and Discussion

Raw data were put into GIS software as input and twooutput data were obtained Figures 23 and 24 illustrate the

Iteratefeature

Select layerby location

Summarystatistics

Get fieldvalue

Calculatefield End

Figure 17 e algorithm determining the extent of damage observed under an earthquake wave in GIS

Figure 18 Geographical location of Gorgan

Figure 19 e organization map of the urban wastewater system

Diameter150200250300400500600700800

Figure 20 e map of Borujen wastewater system (diameter ofpipes)

033

031

Figure 21 e PGA10 map and Borujenrsquos wastewater system

10 Shock and Vibration

extent of damage to pipes using Hazus based on two dif-ferent earthquake velocities namely PGA 2 and PGA 10

Figures 25 and 26 give information about the extent ofdamage under two different earthquakes according to the VImethod

6 Conclusion

Comparing HAUS and VI methods suggests that the formergives more accurate and detailed data so it enables au-thorities to make better decisions for boosting and planningstructures and finding their susceptible points Moreover asthe method helps to find out the extent of damage structureswould suffer after occurrence of an earthquake recon-struction process would be done quickly and precisely

Considering the point that the region has always beenearthquake-prone reviewing data obtained frommaps showa high level of damage Maps are indicating the first pre-diction of the current research that is to say susceptibility ofthe wastewater system to occurrence of any earthquake so itfocuses on the necessity for replacing existent pipelines withmore resistant ones

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

049

052

Figure 22 e PGA2 map and wastewater system

0867840466ndash37318188373181886ndash6595797256595797252ndash94597756

9459775645ndash12323754

1232375405ndash151877321518773244ndash180517101805171083ndash20915689

2091568922ndash237796672377966762ndash26643646

Number of repair10

Figure 23 e total number of Hazus SR2 damage underPGA10

494688108017143028310733633443371853167709116841346914669157521636517644

Number of repair2value

Figure 24 e total number of Hazus SR2 damage under PGA2

Figure 25 e total number of damage under PGA2 accordingto the VI method

Figure 26 e total number of damage under PGA10 accordingto the VI method

Shock and Vibration 11

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T D OrsquoRourke and S S Jeon ldquoFactors affecting the earth-quake damage of water distribution systems in optimizingpost-earthquake lifeline system in optimizing post-life linesystem reliabilityrdquo in Proceedings of the Fifth US Conferenceon Lifeline Earthquake Engineering ASCE Seattle WC USA1999

[2] U Albayrak A Loai and M Morshid ldquoEvaluation of seismicperformance of steel lattice transmission towersrdquo Civil En-gineering Journal vol 6 no 10 pp 1ndash21 2020

[3] B Cai and M H Golestan ldquoTowards bayesian quantificationof permeability in micro-scale porous structuresrdquo e Da-tabase of Micro Networks vol 1 no 4 pp 1ndash13 2020

[4] H Shah and S Chu ldquoSeismic analysis of undergroundstructural elementsrdquo Journal of the Power Division vol 100no 1 pp 53ndash62 1974

[5] E C Goodling ldquoBuried pipingndashan analysis procedure up-daterdquo in Proceedings of the International Symposium onLifeline Earthquake Engineering vol 77 pp 225ndash237 ASMEPortland Oregon May 1983

[6] M Shinozuka and T Koike ldquoEstimation of structural strain inunderground lifeline pipesrdquo Lifeline Earthquake Engineering-Buried Pipeline Seismic Risk and Instrumentation vol 34pp 31ndash48 1979

[7] S Takada and K Tanabe ldquoree-dimensional seismic re-sponse analysis of buried continuous or jointed pipelinesrdquoJournal of Pressure Vessel Technology vol 109 no 1pp 80ndash87 1987

[8] S Takada A Carlo S Bo and X Wuhu Current State of theArts on Pipeline Earthquake Engineering in Japan eConstruction Engineering Research Foundation PuneMaharashtra India vol 1 1992

[9] L Dai D Wang T Wang Q Feng and X Yang ldquoAnalysisand comparison of long-distance pipeline failuresrdquo Journal ofPetroleum Engineering vol 2017 no 1 7 pages Article ID3174636 2017

[10] Y Yang S Yang Z Li et al ldquoAnalysis of hazard area ofdispersion caused by leakage from underground gas-storagecaverns in salt rockrdquo Advances in Civil Engineering vol 2020no 1 11 pages

[11] M Cubrinovski Geotechnical Reconnaissance of the 2010Darfield (New Zealand) Earthquake University of Canter-bury Christchurch New Zealand 2010

[12] Y Maruyama and F Yamazaki ldquoConstruction of fragilitycurve for water distribution pipes based on damage datasetsfrom recent earthquakes in Japanrdquo in Proceedings of the 9thUS National and 10th Canadian Conference on EarthquakeEngineering Toronto ON Canada July 2010

[13] J F Bird and J J Bommer ldquoEarthquake losses due to groundfailurerdquo Engineering Geology vol 75 no 2 pp 147ndash179 2004

[14] M Zare and S Wilkinson ldquoEarthquake damage in wastewatersystem and post earthquake repair methodslimitation andpractcerdquo in Proceedings of the Australian Earthquake Engi-neering Society Conference Novotel Bavossa Valley RwsortBarossa Valley South Australia November 2011

[15] R T Eguchi ldquoSeismic vulnerability models for undergroundpipesrdquo in Proceedings of the International Symposium onEarthquakeBehavior and Safety of Oil and Gas Storage

Facilities Buried Pipelines and Equipment American Societyof Mechanical Engineers (ASME) New York NY USAJanuary 1983

[16] N M Newmark ldquoSeismic design criteria for structures andfacilities Trans-Alaska pipeline systemrdquo in Proceedings of theUS National Conference on Earthquake Engineering Earth-quake Engineering Institute San Francisco CA USA June1975

[17] G Yeh ldquoSeismic analysis of slender buried beamsrdquo eBulletin of the Seismological Society of America vol 64o no 5pp 1551ndash1562 1974

[18] S Takada N Hassani and K Fukuda ldquoA new proposal forsimplified design of buried steel pipes crossing active faultsrdquoEarthquake Engineering amp Structural Dynamics vol 30 no 8pp 1243ndash1257 2001

[19] F R Rofooei and R Qorbani ldquoA parametric study on seismicbehavior of continuous buried pipeline due to wave propa-gationrdquo in Proceedings of the 14th World Conference onEarthquake Engineering Beijing China October 2008

[20] M Hosseini and S Jallili ldquoAssessment of the nonlineearbehavior of connection in water distribution networks fortheir seimic evaluationrdquo Procedia Engineering vol 14pp 2878ndash2883 2011

[21] A M Halabian and T Hokmabadi ldquoA new hybrid model forrigorous analysis of buried pipelines under general faultingaccounting for material and geometrical non-linearities withfocusing on corrugated HDPE pipelinesrdquo Soil Dynamics andEarthquake Engineering vol 115 pp 1ndash17 2018

12 Shock and Vibration

41 Statistical Population Gorgan a city in Golestan Iranwas selected in the current case study research It has beenthe first city in the province equipped with the wastewatersystem As the city experiences dozens of small earthquakesevery day it is worth studying susceptibility of the waste-water system to earthquake e wastewater system is124meters in length (Figure 18)

First maps developed in AutoCAD software pertinent tothe Gorgan wastewater system were collected in order toassess the extent of damage to the system due to earthquakesNext maps were turned into GIS data Both 2 and 10 percentdanger analysis maps were adjusted to aerial photos andthen corrected ones were entered into GIS software tomeasure the seismic susceptibility ratio under maximumland movement

42 Sampling Method and Sample Size In the current re-search two types of data including maps of seismic analysisand wastewater pipelinesrsquo code were used e former in-cludes curves aligned with velocity of potential approachesof the vertical element which are pertinent to a return periodof 75 years for 2 PGA and a return period of 475 years for10 PGA for an estimated 50 year service life

43 e Map of Selected Wastewater System e Gorganwater and wastewater organization has provided the re-searcher with given maps as well as a file containing pipe-linesrsquo codes (Figures 19 and 20) en the file entered intothe GIS software and improved

44 Data Analysis Research variables include characteris-tics of pipes as well as velocity of the earthquake which havebeen drawn by adjusting rough maps of earthquake velocityand the cityrsquos wastewater system (Figures 21 and 22)

5 Results and Discussion

Raw data were put into GIS software as input and twooutput data were obtained Figures 23 and 24 illustrate the

Iteratefeature

Select layerby location

Summarystatistics

Get fieldvalue

Calculatefield End

Figure 17 e algorithm determining the extent of damage observed under an earthquake wave in GIS

Figure 18 Geographical location of Gorgan

Figure 19 e organization map of the urban wastewater system

Diameter150200250300400500600700800

Figure 20 e map of Borujen wastewater system (diameter ofpipes)

033

031

Figure 21 e PGA10 map and Borujenrsquos wastewater system

10 Shock and Vibration

extent of damage to pipes using Hazus based on two dif-ferent earthquake velocities namely PGA 2 and PGA 10

Figures 25 and 26 give information about the extent ofdamage under two different earthquakes according to the VImethod

6 Conclusion

Comparing HAUS and VI methods suggests that the formergives more accurate and detailed data so it enables au-thorities to make better decisions for boosting and planningstructures and finding their susceptible points Moreover asthe method helps to find out the extent of damage structureswould suffer after occurrence of an earthquake recon-struction process would be done quickly and precisely

Considering the point that the region has always beenearthquake-prone reviewing data obtained frommaps showa high level of damage Maps are indicating the first pre-diction of the current research that is to say susceptibility ofthe wastewater system to occurrence of any earthquake so itfocuses on the necessity for replacing existent pipelines withmore resistant ones

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

049

052

Figure 22 e PGA2 map and wastewater system

0867840466ndash37318188373181886ndash6595797256595797252ndash94597756

9459775645ndash12323754

1232375405ndash151877321518773244ndash180517101805171083ndash20915689

2091568922ndash237796672377966762ndash26643646

Number of repair10

Figure 23 e total number of Hazus SR2 damage underPGA10

494688108017143028310733633443371853167709116841346914669157521636517644

Number of repair2value

Figure 24 e total number of Hazus SR2 damage under PGA2

Figure 25 e total number of damage under PGA2 accordingto the VI method

Figure 26 e total number of damage under PGA10 accordingto the VI method

Shock and Vibration 11

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T D OrsquoRourke and S S Jeon ldquoFactors affecting the earth-quake damage of water distribution systems in optimizingpost-earthquake lifeline system in optimizing post-life linesystem reliabilityrdquo in Proceedings of the Fifth US Conferenceon Lifeline Earthquake Engineering ASCE Seattle WC USA1999

[2] U Albayrak A Loai and M Morshid ldquoEvaluation of seismicperformance of steel lattice transmission towersrdquo Civil En-gineering Journal vol 6 no 10 pp 1ndash21 2020

[3] B Cai and M H Golestan ldquoTowards bayesian quantificationof permeability in micro-scale porous structuresrdquo e Da-tabase of Micro Networks vol 1 no 4 pp 1ndash13 2020

[4] H Shah and S Chu ldquoSeismic analysis of undergroundstructural elementsrdquo Journal of the Power Division vol 100no 1 pp 53ndash62 1974

[5] E C Goodling ldquoBuried pipingndashan analysis procedure up-daterdquo in Proceedings of the International Symposium onLifeline Earthquake Engineering vol 77 pp 225ndash237 ASMEPortland Oregon May 1983

[6] M Shinozuka and T Koike ldquoEstimation of structural strain inunderground lifeline pipesrdquo Lifeline Earthquake Engineering-Buried Pipeline Seismic Risk and Instrumentation vol 34pp 31ndash48 1979

[7] S Takada and K Tanabe ldquoree-dimensional seismic re-sponse analysis of buried continuous or jointed pipelinesrdquoJournal of Pressure Vessel Technology vol 109 no 1pp 80ndash87 1987

[8] S Takada A Carlo S Bo and X Wuhu Current State of theArts on Pipeline Earthquake Engineering in Japan eConstruction Engineering Research Foundation PuneMaharashtra India vol 1 1992

[9] L Dai D Wang T Wang Q Feng and X Yang ldquoAnalysisand comparison of long-distance pipeline failuresrdquo Journal ofPetroleum Engineering vol 2017 no 1 7 pages Article ID3174636 2017

[10] Y Yang S Yang Z Li et al ldquoAnalysis of hazard area ofdispersion caused by leakage from underground gas-storagecaverns in salt rockrdquo Advances in Civil Engineering vol 2020no 1 11 pages

[11] M Cubrinovski Geotechnical Reconnaissance of the 2010Darfield (New Zealand) Earthquake University of Canter-bury Christchurch New Zealand 2010

[12] Y Maruyama and F Yamazaki ldquoConstruction of fragilitycurve for water distribution pipes based on damage datasetsfrom recent earthquakes in Japanrdquo in Proceedings of the 9thUS National and 10th Canadian Conference on EarthquakeEngineering Toronto ON Canada July 2010

[13] J F Bird and J J Bommer ldquoEarthquake losses due to groundfailurerdquo Engineering Geology vol 75 no 2 pp 147ndash179 2004

[14] M Zare and S Wilkinson ldquoEarthquake damage in wastewatersystem and post earthquake repair methodslimitation andpractcerdquo in Proceedings of the Australian Earthquake Engi-neering Society Conference Novotel Bavossa Valley RwsortBarossa Valley South Australia November 2011

[15] R T Eguchi ldquoSeismic vulnerability models for undergroundpipesrdquo in Proceedings of the International Symposium onEarthquakeBehavior and Safety of Oil and Gas Storage

Facilities Buried Pipelines and Equipment American Societyof Mechanical Engineers (ASME) New York NY USAJanuary 1983

[16] N M Newmark ldquoSeismic design criteria for structures andfacilities Trans-Alaska pipeline systemrdquo in Proceedings of theUS National Conference on Earthquake Engineering Earth-quake Engineering Institute San Francisco CA USA June1975

[17] G Yeh ldquoSeismic analysis of slender buried beamsrdquo eBulletin of the Seismological Society of America vol 64o no 5pp 1551ndash1562 1974

[18] S Takada N Hassani and K Fukuda ldquoA new proposal forsimplified design of buried steel pipes crossing active faultsrdquoEarthquake Engineering amp Structural Dynamics vol 30 no 8pp 1243ndash1257 2001

[19] F R Rofooei and R Qorbani ldquoA parametric study on seismicbehavior of continuous buried pipeline due to wave propa-gationrdquo in Proceedings of the 14th World Conference onEarthquake Engineering Beijing China October 2008

[20] M Hosseini and S Jallili ldquoAssessment of the nonlineearbehavior of connection in water distribution networks fortheir seimic evaluationrdquo Procedia Engineering vol 14pp 2878ndash2883 2011

[21] A M Halabian and T Hokmabadi ldquoA new hybrid model forrigorous analysis of buried pipelines under general faultingaccounting for material and geometrical non-linearities withfocusing on corrugated HDPE pipelinesrdquo Soil Dynamics andEarthquake Engineering vol 115 pp 1ndash17 2018

12 Shock and Vibration

extent of damage to pipes using Hazus based on two dif-ferent earthquake velocities namely PGA 2 and PGA 10

Figures 25 and 26 give information about the extent ofdamage under two different earthquakes according to the VImethod

6 Conclusion

Comparing HAUS and VI methods suggests that the formergives more accurate and detailed data so it enables au-thorities to make better decisions for boosting and planningstructures and finding their susceptible points Moreover asthe method helps to find out the extent of damage structureswould suffer after occurrence of an earthquake recon-struction process would be done quickly and precisely

Considering the point that the region has always beenearthquake-prone reviewing data obtained frommaps showa high level of damage Maps are indicating the first pre-diction of the current research that is to say susceptibility ofthe wastewater system to occurrence of any earthquake so itfocuses on the necessity for replacing existent pipelines withmore resistant ones

Data Availability

e data used to support the findings of this study areavailable from the corresponding author upon request

049

052

Figure 22 e PGA2 map and wastewater system

0867840466ndash37318188373181886ndash6595797256595797252ndash94597756

9459775645ndash12323754

1232375405ndash151877321518773244ndash180517101805171083ndash20915689

2091568922ndash237796672377966762ndash26643646

Number of repair10

Figure 23 e total number of Hazus SR2 damage underPGA10

494688108017143028310733633443371853167709116841346914669157521636517644

Number of repair2value

Figure 24 e total number of Hazus SR2 damage under PGA2

Figure 25 e total number of damage under PGA2 accordingto the VI method

Figure 26 e total number of damage under PGA10 accordingto the VI method

Shock and Vibration 11

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T D OrsquoRourke and S S Jeon ldquoFactors affecting the earth-quake damage of water distribution systems in optimizingpost-earthquake lifeline system in optimizing post-life linesystem reliabilityrdquo in Proceedings of the Fifth US Conferenceon Lifeline Earthquake Engineering ASCE Seattle WC USA1999

[2] U Albayrak A Loai and M Morshid ldquoEvaluation of seismicperformance of steel lattice transmission towersrdquo Civil En-gineering Journal vol 6 no 10 pp 1ndash21 2020

[3] B Cai and M H Golestan ldquoTowards bayesian quantificationof permeability in micro-scale porous structuresrdquo e Da-tabase of Micro Networks vol 1 no 4 pp 1ndash13 2020

[4] H Shah and S Chu ldquoSeismic analysis of undergroundstructural elementsrdquo Journal of the Power Division vol 100no 1 pp 53ndash62 1974

[5] E C Goodling ldquoBuried pipingndashan analysis procedure up-daterdquo in Proceedings of the International Symposium onLifeline Earthquake Engineering vol 77 pp 225ndash237 ASMEPortland Oregon May 1983

[6] M Shinozuka and T Koike ldquoEstimation of structural strain inunderground lifeline pipesrdquo Lifeline Earthquake Engineering-Buried Pipeline Seismic Risk and Instrumentation vol 34pp 31ndash48 1979

[7] S Takada and K Tanabe ldquoree-dimensional seismic re-sponse analysis of buried continuous or jointed pipelinesrdquoJournal of Pressure Vessel Technology vol 109 no 1pp 80ndash87 1987

[8] S Takada A Carlo S Bo and X Wuhu Current State of theArts on Pipeline Earthquake Engineering in Japan eConstruction Engineering Research Foundation PuneMaharashtra India vol 1 1992

[9] L Dai D Wang T Wang Q Feng and X Yang ldquoAnalysisand comparison of long-distance pipeline failuresrdquo Journal ofPetroleum Engineering vol 2017 no 1 7 pages Article ID3174636 2017

[10] Y Yang S Yang Z Li et al ldquoAnalysis of hazard area ofdispersion caused by leakage from underground gas-storagecaverns in salt rockrdquo Advances in Civil Engineering vol 2020no 1 11 pages

[11] M Cubrinovski Geotechnical Reconnaissance of the 2010Darfield (New Zealand) Earthquake University of Canter-bury Christchurch New Zealand 2010

[12] Y Maruyama and F Yamazaki ldquoConstruction of fragilitycurve for water distribution pipes based on damage datasetsfrom recent earthquakes in Japanrdquo in Proceedings of the 9thUS National and 10th Canadian Conference on EarthquakeEngineering Toronto ON Canada July 2010

[13] J F Bird and J J Bommer ldquoEarthquake losses due to groundfailurerdquo Engineering Geology vol 75 no 2 pp 147ndash179 2004

[14] M Zare and S Wilkinson ldquoEarthquake damage in wastewatersystem and post earthquake repair methodslimitation andpractcerdquo in Proceedings of the Australian Earthquake Engi-neering Society Conference Novotel Bavossa Valley RwsortBarossa Valley South Australia November 2011

[15] R T Eguchi ldquoSeismic vulnerability models for undergroundpipesrdquo in Proceedings of the International Symposium onEarthquakeBehavior and Safety of Oil and Gas Storage

Facilities Buried Pipelines and Equipment American Societyof Mechanical Engineers (ASME) New York NY USAJanuary 1983

[16] N M Newmark ldquoSeismic design criteria for structures andfacilities Trans-Alaska pipeline systemrdquo in Proceedings of theUS National Conference on Earthquake Engineering Earth-quake Engineering Institute San Francisco CA USA June1975

[17] G Yeh ldquoSeismic analysis of slender buried beamsrdquo eBulletin of the Seismological Society of America vol 64o no 5pp 1551ndash1562 1974

[18] S Takada N Hassani and K Fukuda ldquoA new proposal forsimplified design of buried steel pipes crossing active faultsrdquoEarthquake Engineering amp Structural Dynamics vol 30 no 8pp 1243ndash1257 2001

[19] F R Rofooei and R Qorbani ldquoA parametric study on seismicbehavior of continuous buried pipeline due to wave propa-gationrdquo in Proceedings of the 14th World Conference onEarthquake Engineering Beijing China October 2008

[20] M Hosseini and S Jallili ldquoAssessment of the nonlineearbehavior of connection in water distribution networks fortheir seimic evaluationrdquo Procedia Engineering vol 14pp 2878ndash2883 2011

[21] A M Halabian and T Hokmabadi ldquoA new hybrid model forrigorous analysis of buried pipelines under general faultingaccounting for material and geometrical non-linearities withfocusing on corrugated HDPE pipelinesrdquo Soil Dynamics andEarthquake Engineering vol 115 pp 1ndash17 2018

12 Shock and Vibration

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T D OrsquoRourke and S S Jeon ldquoFactors affecting the earth-quake damage of water distribution systems in optimizingpost-earthquake lifeline system in optimizing post-life linesystem reliabilityrdquo in Proceedings of the Fifth US Conferenceon Lifeline Earthquake Engineering ASCE Seattle WC USA1999

[2] U Albayrak A Loai and M Morshid ldquoEvaluation of seismicperformance of steel lattice transmission towersrdquo Civil En-gineering Journal vol 6 no 10 pp 1ndash21 2020

[3] B Cai and M H Golestan ldquoTowards bayesian quantificationof permeability in micro-scale porous structuresrdquo e Da-tabase of Micro Networks vol 1 no 4 pp 1ndash13 2020

[4] H Shah and S Chu ldquoSeismic analysis of undergroundstructural elementsrdquo Journal of the Power Division vol 100no 1 pp 53ndash62 1974

[5] E C Goodling ldquoBuried pipingndashan analysis procedure up-daterdquo in Proceedings of the International Symposium onLifeline Earthquake Engineering vol 77 pp 225ndash237 ASMEPortland Oregon May 1983

[6] M Shinozuka and T Koike ldquoEstimation of structural strain inunderground lifeline pipesrdquo Lifeline Earthquake Engineering-Buried Pipeline Seismic Risk and Instrumentation vol 34pp 31ndash48 1979

[7] S Takada and K Tanabe ldquoree-dimensional seismic re-sponse analysis of buried continuous or jointed pipelinesrdquoJournal of Pressure Vessel Technology vol 109 no 1pp 80ndash87 1987

[8] S Takada A Carlo S Bo and X Wuhu Current State of theArts on Pipeline Earthquake Engineering in Japan eConstruction Engineering Research Foundation PuneMaharashtra India vol 1 1992

[9] L Dai D Wang T Wang Q Feng and X Yang ldquoAnalysisand comparison of long-distance pipeline failuresrdquo Journal ofPetroleum Engineering vol 2017 no 1 7 pages Article ID3174636 2017

[10] Y Yang S Yang Z Li et al ldquoAnalysis of hazard area ofdispersion caused by leakage from underground gas-storagecaverns in salt rockrdquo Advances in Civil Engineering vol 2020no 1 11 pages

[11] M Cubrinovski Geotechnical Reconnaissance of the 2010Darfield (New Zealand) Earthquake University of Canter-bury Christchurch New Zealand 2010

[12] Y Maruyama and F Yamazaki ldquoConstruction of fragilitycurve for water distribution pipes based on damage datasetsfrom recent earthquakes in Japanrdquo in Proceedings of the 9thUS National and 10th Canadian Conference on EarthquakeEngineering Toronto ON Canada July 2010

[13] J F Bird and J J Bommer ldquoEarthquake losses due to groundfailurerdquo Engineering Geology vol 75 no 2 pp 147ndash179 2004

[14] M Zare and S Wilkinson ldquoEarthquake damage in wastewatersystem and post earthquake repair methodslimitation andpractcerdquo in Proceedings of the Australian Earthquake Engi-neering Society Conference Novotel Bavossa Valley RwsortBarossa Valley South Australia November 2011

[15] R T Eguchi ldquoSeismic vulnerability models for undergroundpipesrdquo in Proceedings of the International Symposium onEarthquakeBehavior and Safety of Oil and Gas Storage

Facilities Buried Pipelines and Equipment American Societyof Mechanical Engineers (ASME) New York NY USAJanuary 1983

[16] N M Newmark ldquoSeismic design criteria for structures andfacilities Trans-Alaska pipeline systemrdquo in Proceedings of theUS National Conference on Earthquake Engineering Earth-quake Engineering Institute San Francisco CA USA June1975

[17] G Yeh ldquoSeismic analysis of slender buried beamsrdquo eBulletin of the Seismological Society of America vol 64o no 5pp 1551ndash1562 1974

[18] S Takada N Hassani and K Fukuda ldquoA new proposal forsimplified design of buried steel pipes crossing active faultsrdquoEarthquake Engineering amp Structural Dynamics vol 30 no 8pp 1243ndash1257 2001

[19] F R Rofooei and R Qorbani ldquoA parametric study on seismicbehavior of continuous buried pipeline due to wave propa-gationrdquo in Proceedings of the 14th World Conference onEarthquake Engineering Beijing China October 2008

[20] M Hosseini and S Jallili ldquoAssessment of the nonlineearbehavior of connection in water distribution networks fortheir seimic evaluationrdquo Procedia Engineering vol 14pp 2878ndash2883 2011

[21] A M Halabian and T Hokmabadi ldquoA new hybrid model forrigorous analysis of buried pipelines under general faultingaccounting for material and geometrical non-linearities withfocusing on corrugated HDPE pipelinesrdquo Soil Dynamics andEarthquake Engineering vol 115 pp 1ndash17 2018

12 Shock and Vibration