VicRoads Bridge Design Technical Notes

8/17/2019 VicRoads Bridge Design Technical Notes

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VERSION: 1.0 DATE: December 2005 Page 1

vicroads

2005/08

TEMPORARY PRECAST CONCRETE BARRIERS FORTL-3 LOADING

Bridge Technical Note

1. GENERAL

This technical note supersedes technical note 2005/003 Retrofitting of temporary precast concrete barriers

for TL-3 loading. It is for use on all Victorian roads.

From 1 January 2006, the Worksite Safety – Traffic Management Code of Practice, introduced under the

Road Management Act in December 2004, imposes new requirements.

The 6 m New Jersey profile concrete barriers which have commonly been used by VicRoads contractors

with steel box section connectors have not been tested for compliance with the NCHRP 350 test level 3 (TL-

3) requirements.

Six metre New Jersey profile concrete barriers fitted with pin and loop connections have been tested in

America and have met the NCHRP 350 test level 3 (TL-3) requirement.

This technical note provides drawings for both the retrofitting of pin and loop connections to VicRoads

existing 6 m New Jersey profile concrete barriers and for new barriers to comply with the performance

requirements of successfully tested systems. The retrofit and new barrier designs comply with Clause 2.3.16

of AS/NZS 3845-1999.

2. DEFINITIONS

Temporary concrete median barrier – The barriers referred to in this technical note are those shown on

standard drawings 181702 and 181703 (refer Appendix Three).

Test Level 3 (TL-3) – Is a test level specified in the Transportation Research Board-National Cooperative

Highway Research Program – Report 350 (TRB-NCHRP 350) Recommended Procedures for the Safety

Performance Evaluation of Highway Features.


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Temporary precast concrete barriers for TL-3 loading


3. WORKSITE SAFETY – TRAFFIC MANAGEMENT CODE OF PRACTICE ANDAUSTRALIAN STANDARD REQUIREMENTS

The Worksite Safety – Traffic Management Code of Practice states that AS/NZS 3845-1999: Road Safety

Barriers, shall be used to determine barriers that are to be used at worksites. In particular the Code states that

AS 1742.3-2002 provides that all safety barriers shall conform to the requirements of AS/NZS 3845-1999.

“AS/NZS 3845-1999 provides that –

(a) “all road safety barrier systems and crash attenuators shall be tested in accordance with the

procedures specified in this (AS/NZS 3845-1999) Standard”; and

(b)

NCHRP Report 350: Recommended Procedures for the Safety Performance Evaluation of

Highway Features (“NCHRP 350”) “shall be the basis of testing procedures” for safety barriers.”

AS/NZS 3845-1999 states that barrier systems shall be tested. For all barrier systems including precast

concrete pin and loop barriers AS/NZS 3845-1999 allows for modifications through clause 2.3.16.

“Clause 2.3.16 Modifications

Modifications shall not be made to any road safety barrier system, unless crash testing, computersimulation or other professionally accepted methods show that the change is acceptable.”

4. DESCRIPTION OF THE IDAHO TRANSPORTATION DEPARTMENT (ITD) BARRIER

The VicRoads retrofit and new barrier designs are based on the successfully tested pin and loop style

connection system developed by the Idaho Transportation Department (ITD). The ITD barrier has been

accepted by the American Department of Transportation Federal Highway Authority (FHWA) as meeting the

TL-3 requirement (refer Appendix One).

Drawings of the barrier are attached in Appendix Two. The barrier consists of two loops projecting from

each end of the precast barrier. The loops are formed from 19 mm diameter bar of grade A36 steel whichhas a nominal yield strength of 250 MPa (36 ksi). Loops from adjacent units overlap so that a 32 mm

diameter pin can be inserted through the loops. The loops project from the concrete surface to allow

approximately 10% rotation between barrier units.

Details of tests on the ITD barrier (with deflection data) are given in Appendix One.

5. RETROFIT OF EXISTING VICROADS TEMPORARY CONCRETE BARRIERS

A retrofit to VicRoads concrete median barriers and standard drawings for the barriers are shown in

Appendix Three. The retrofit designs are based on the ITD connection system.

Anchor Mk A

A 16 x 30 mm steel plate, Grade 350 to AS/NZS 3678, galvanised and bent around a 64 mm diameter pin

forms the lower loop.

Anchor Mk B

A 16 x 30 mm steel plate, Grade 350 to AS/NZS 3678, galvanised and bent around a 64 mm diameter pin

forms the upper loop. The upper loop is connected through a 20 mm thick steel plate that is anchored by two

20 mm diameter plain Grade 500 E bars. The bars are embedded so that they will transfer load into the mesh

reinforcement of the existing barrier. The E Grade bars were chosen for their strength and ductility to

provide an additional factor of safety over the ITD system.

The existing VicRoads barriers have a F718 mesh which provides less reinforcement longitudinally than the

ITD system which utilises 3 No. 16 mm diameter bars on each face of the barrier. The VicRoads barrier is

100 mm wider than the ITD system.


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The retrofit provides for approximately 8-10 degrees of rotation at the connection compared to 10 degrees

with the ITD system. The difference in rotation capacity is not considered to be significant with respect to

modifying the performance of the temporary barrier system.

The mass of the retrofit barrier is approximately 4500 kg compared to the ITD tested segments weights of

3630 kg.

Prior to retrofitting, it shall be certified by a firm prequalified with VicRoads to CS level that the barrier to

be retrofitted was designed in accordance with the drawings shown in Appendix Three. This may involve

the use of a cover meter to confirm the details of reinforcement and taking physical measurements of the

units.

6. NEW TEMPORARY PRECAST CONCRETE BARRIERS

A new VicRoads temporary concrete median barrier design is shown in Appendix Four. The design is based

on a modification to the ITD tested system (refer to Appendix Two).

The new VicRoads temporary concrete median barrier utilises the New Jersey shape as the ITD barrier has

this shape. The FHWA has no plans to limit the use of the New Jersey shape or require the use of F-shape

barriers for temporary applications. The FHWA has found that as temporary barriers deflect upon impact,

there is not as much difference in the performance of the two barriers. (Reference 8).

7. ALTERNATIVE DESIGNS

Temporary barrier designs consistent with Clause 2.3.16 of AS/NZS 3845-1999 shall be designed by firms

prequalified to CS level and proofed by firms of PE level. For details of VicRoads Prequalification scheme

refer to the VicRoads website (www.vicroads.vic.gov.au).

8. INSPECTION OF TEMPORARY ROADSIDE BARRIERS

Barriers shall be inspected in accordance with AS/NZS 3845-1999 Section 2 Road Safety Barrier Systems

and Crash Attenuators. Barriers which show damage such as cracking and spalling of concrete from a

collision shall be removed from service.

9. INSTALLATION OF TEMPORARY ROADSIDE BARRIERS

Temporary barriers as detailed on Drawings 479899, 479917 and 479918 shall be connected with connecting

pins as shown. The barrier installation shall be in accordance with this technical note and the requirementsshown on the ITD barrier drawing G-2-A-1.

The ITD barrier was tested for installation onto aged chip-sealed asphalt. Installation on other materials

needs to be justified.

The position of the barrier in relation to the asphalt shall consider both the installed and deflected positions

from impact. Refer to G-2-A-1 drawing by ITD (Appendix Two).

The end treatment for the barrier shall be site specific. The end of the barriers may be tapered until they are

outside the clear zone. The clear zone width which varies due to factors such as 85th percentile speed can be

assessed based on Figure 3.9.2 of the VicRoads Road Design Guidelines, Part 3 – Cross Section Elements.

Appropriate end treatments as listed in Road Design Note 9-12a should be used unless the barrier can be

terminated outside the clear zone.


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Where barriers cannot be terminated outside of the clear zone, barriers shall be placed to shield the worksite

from errant vehicles that leave the traffic lane upstream of the worksite. The length of barrier required

beyond the worksite to provide protection from errant vehicles is defined as the Barrier Length of Need, LON-Refer Fig 1. The LON required for barrier installations parallel to traffic lanes and flared away from traffic

lanes at a rate of 1: 10 are provided in Tables 1 & 2 respectively.

Roadworks

Speed Limit

(km/h)

100 80 60

BarrierOffset

(m)

Barrier Length of Need, LON (m)

≤ 1.0 90 70 45

3.0 70 45 255

5.0 45 255

0

7.0 255

0 0

Table 1 – Length of Need for Barriers Parallel to Traffic Lane

Roadworks

Speed Limit

(km/h)

100 80 60

Barrier

Offset

(m)

Barrier Length of Need, LON (m)

≤ 1.0 45 355

255

3.0 355

255

155

5.0 255

155

0

7.0 15 5

0 0

Table 2 – Length of Need for Barriers Flared at 1:10 from Traffic Lane

Notes: 1. Roadworks speed limit is the speed limit applicable during working hours for the work site.2. Barrier offset is the distance between the barrier and the edge of the nearest approach direction

traffic lane.


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3. Barrier Length of Need (LON) is the length of barrier required measured from the point in the

work site closest to approaching traffic to the end of the barrier. The length of any barrier end

treatment should be added to the LON 4. Where the LON is less than the minimum length of barrier required for the barrier to be

effective at the appropriate NCHRP 350 Test Level at the start of the work site, the minimum

length of barrier required for it to be effective shall be adopted instead of the LON.

5. Those lengths annotated in Tables 1 and 2 are less than the minimum length of barrier required

beyond the work site for the VicRoads retrofit design to be effective to NCHRP 350 Test

Level 3 at the start of the work site.

6. Flaring of barriers away from traffic lanes at taper rates of up to 1:10 is only acceptable where

the terrain between the traffic lane and barrier is traversable and relatively flat, with a

maximum cross slope of 10 (H): 1(V).

7. Interpolation of LON within Tables 1 & 2 for barrier offsets other than those listed and between

Tables 1 & 2 for barrier flare rates less than 1:10 is acceptable.

8. Where site constraints prevent the adoption of LON as per Tables 1 & 2, the maximum length

of barrier possible beyond the worksite shall be installed together with other appropriate

measures to minimise the risk posed by errant vehicles.

For the VicRoads retrofit design, it is considered that at least 36m of barrier shall extend past each end of the

areas of works to be protected to ensure that the barrier will be effective to NCHRP 350 Test Level 3

throughout the work site. At least 18 metres of the barrier that extends past the area of works shall be

parallel with the road alignment. To comply with AS 3845 Clause 2.3.16 lesser lengths shall not be used

unless crash testing, computer simulation or other professionally accepted methods show that a lesser length

is acceptable.

For alternative temporary barrier designs, the length of barrier required past the work site for the barrier to be

effective at the appropriate NCHRP 350 test level shall be determined as part of the design.

For proprietary barrier systems, the length of barrier required past the work site for the barrier to be effective

at the appropriate NCHRP 350 test level shall be determined in accordance with the manufacturer’sspecifications.

10. BARRIER IDENTIFICATION

Barriers shall be identified in accordance with AS/NZS 3845-1999 clause 2.3.5. In addition to the

requirements of AS/NZS 3845-1999, the performance level, date of construction, and VicRoads drawing

number for all retrofitted and new barriers shall be clearly marked on the barrier. For alternative designs,

VicRoads drawing numbers can be obtained from the VicRoads Plan Filing Department located within

VicRoads Design. A copy of the drawings shall be lodged with the Plan Filing Department so that VicRoads

can monitor the performance of these barriers.

11. REFERENCES

1.

Idaho Transportation Department standard drawings G-2-A-1 sheets 1 and 2 of 2 (refer

Appendix Two).

2. Road management Act 2004, Worksite Safety – Traffic Management, Code of Practice ,

Victoria Government Gazette No. S276 (available on VicRoads website

www.vicroads.vic.gov.au)

3.

TRB-NCHRP Report 350. Recommended Procedure for the Safety Performance Evaluation of

Highway Features (available from

www.safety.fhwa.dot.gov/roadway_dept/road_hardware/nchrp_350.htm)

4.

AS/NZS 3845-1999 – Road safety barrier systems (available from www.standards.com.au).

5. AS 1742.3-2002 Manual of uniform traffic control devices (available from

www.standards.com.au)


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6. VicRoads website (www.vicroads.vic.gov.au) for details of the VicRoads prequalification

system.

7.

Road Design Note 9-12a – Accepted safety barrier products (available from VicRoads website

www.vicroads.vic.gov.au)

8.

Letter dated July 17, 2000 from James E. St. John, Federal Highway Administration to Mr

Freddie Simmons, Florida Department of Transportation (available from

http://www.dot.state.fl.us/construction/download/ConstConf04/pdf%20files/Temporary%20Tra

ffic%20Railing%20Barrier.pdf )

9. VicRoads Road Design Guidelines, Part 3 – Cross Section Elements (available from VicRoads

bookshop www.vicroads.vic.gov.au)

MIKE VEREY

PRINCIPAL BRIDGE ENGINEER

Contact Officers

Author: Dr Andrew Sonnenberg

For further information please contact:

Principal Bridge Engineer

3 Prospect Hill Road Camberwell Vic 3124

Telephone: (03) 9811 8307

Facsimile: (03) 9811 8329

Email: [email protected]

Bridge Tech Notes are subject to periodic review and may be superseded.

Bridge Design File No: 4688This technical note supersedes technical note 2005/003 Retrofitting of temporary precast concrete barriers

for TL-3 loading


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APPENDIX ONE ACCEPTANCE LETTER FOR THE ITD PRECAST CONCRETE BARRIER


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APPENDIX TWO DRAWINGS FOR THE ITD PRECAST CONCRETE BARRIER


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APPENDIX THREE – RETROFIT TO VICROADS TEMPORARY MEDIAN BARRIER


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APPENDIX FOUR – NEW TEMPORARY MEDIAN BARRIER


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vicroads

DESIGN PARAMETERS FOR DRIVEN PILES

1. INTRODUCTION

This Bridge Technical Note (BTN) specifies the minimum VicRoads requirements for the design and

specification of driven pile foundations for road structures, including vehicle bridges, pedestrian bridges,

sign structures, noise barriers and similar. It specifies the requirements for design of precast concrete piles

and steel piles (“H” section and shell piles). It supersedes the 1996 version of this BTN

This BTN shall be read in conjunction with AS 2159 “Piling- Design and Installation”, AS 5100 – “Bridge

Design” and VicRoads’ Standard Specification for Roadworks and Bridgeworks and shall take precedence

over these documents. Reference shall also be made to BTN 99/018 “Manufacturing Details for Precast

Concrete Piles”.

2. STANDARDS

This Technical Note is based on the requirements of VicRoads Standard Specification for Roadworks and

Bridgeworks and relevant Australian standards, including but not limited to the (current edition) of the

following:

AS 1012-PART9

AS/NZS 1554-PART 1

AS/NZS 1554-PART 3

AS/NZS 1554-PART 5

AS 2159

AS 3600

AS 3678

AS 3679

AS/NZS 4671

AS 1311

AS 5100

VicRoads

Method for the Determination of the Compressive Strength of Concrete

Structural Steel Welding - Welding of Steel Structures

Structural Steel Welding - Welding of Reinforcing Steel

Structural Steel Welding - Welding of Steel Structures Subject to high

levels of Fatigue Loading

Piling - Design and Installation

Concrete Structures

Structural Steel - Hot-rolled Plates, Floor Plates and Slabs

Structural Steel

Steel reinforcing materials

Steel tendons for prestressed concrete -7 wire stress-relieved steel strand

Bridge Design

Standard Specification for Roadworks and Bridgeworks

1996/001 Bridge Technical Note


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Design Parameters for Driven Piles


3. DEFINITIONS

Calculated Set The calculated average penetration per blow from 10 consecutive blows to achieve

the required resistance.

Contract Level Reduced level of the pile toe shown on the Drawings.

Geotechnical Strength

Reduction Factor Φg

Refer to AS 5100.3 and AS 2159.

Previously referred to as the Material Factor in 1996 version of this BTN.

Design Pile Load N* Ultimate limit state design axial pile load. Refer to Clause 4.3.

Hiley formula A method of estimating pile capacity based on empirical values for the pile and

driving system using impulse-momentum principles. The formula specified is

based on Chellis’ (1941, 1961) modified version of an equation attributed to A.

Hiley (1930).

Minimum PenetrationDepth

Minimum length of pile below existing surface level or other specified surfacelevel at pile location shown on the Drawings.

Net Driving Energy Driving energy at the top of the pile ie after hammer, helmet and cushion losses.

Nominal Driving Energy Driving energy nominally imparted by the hammer, ie before hammer, helmet and

cushion losses are accounted for.

Pile test load N The measured axial load capacity of a test pile or representative pile.

It is equivalent to the characteristic ultimate limit state axial resistance of the pile.

Refer to Clause 4.3.

Representative Pile A pile that represents a number of piles (which are to be driven to a resistance)

for the purpose of determining driving parameters using Dynamic Testing.

Representative Piles which are driven prior to the manufacture of the represented

piles are also Test Piles.

Representative Testing Dynamic Testing on a representative pile to determine the driving parameters for a

number of piles.

Represented Pile A pile whose capacity is calculated by extrapolation of the results from the testing

of a representative pile(s).

Splice Structural connection between lengths of pile sections that may be subject to

driving.

Test Piles Piles manufactured and driven to enable the Superintendent to confirm or alter, as

necessary, the pile lengths shown on the Drawings.

Test Piles which represent piles driven to a resistance are also Representative Piles.


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4. MATERIALS

4.1 GENERAL

Reference should be made to AS 2159, AS 5100.5, AS 5100.6, VicRoads Specification for Roadworks and

Bridgeworks, BTN 99/018, other relevant Australian Standards and this BTN to determine material

properties to be used for the design and manufacture of driven steel and precast concrete piles.

4.2 CONCRETE

Concrete for precast reinforced and prestressed concrete piles shall comply with the requirements of this

BTN, BTN 99/018, AS 5100.5 and VicRoads Standard Specification for Roadworks and Bridgeworks,

Sections 610 and 620.

4.3 STRUCTURAL STEEL

Structural steel for driven piles shall comply with the requirements of AS 5100.6 and Section 630 of

VicRoads Specification for Roadworks and Bridgeworks. Welding of structural steel shall comply with the

requirements of AS/NZS 1554 Part 1.

Where welds are subject to an alternating or fluctuating tensile or compressive stress they shall comply with

AS/NZS 1554 Part 5. The designer shall determine the appropriate number of cycles to be used and stress

limits for the component detail under consideration. Reference shall be made to the fatigue provisions of AS

5100.6.

4.4 REINFORCEMENT

Reinforcing steel for driven and cast insitu pile concrete shall comply with the requirements of AS/NZS4671, AS 5100.5 and Section 611 of the VicRoads Specification for Roadworks and Bridgeworks.

Welding of reinforcement shall comply with the requirements of AS/NZS 1554 Part 3.

Where welds are subject to an alternating or fluctuating tensile or compressive stress they shall comply with

AS/NZS 1554 Part 5. The designer shall determine the appropriate number of cycles to be used and stress

limits for the component detail under consideration. Reference shall be made to the fatigue provisions of AS

5100.5.

4.5 OTHER MATERIALS

Other materials, not specified herein, shall comply with the appropriate Australian standard or if no such

standard is available, with Specifications or Standards approved by VicRoads.

5. PILE DESIGN

5.1 DURABILITY

Specific reference shall be made to the requirements of AS 5100.5, AS 5100.6, AS 5100.3 Clause 11.3.4 and

AS 2159 Section 6.

Where steel, composite or jointed piles are anticipated the designer shall ensure that the geotechnicalinformation includes a report on soil reactivity and ground water movement.


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The following factors may influence durability of steel, composite or jointed piles and shall be assessed by

the designer:

(a) Sites with possible electrolytic action due to stray currents, very low soil resistivity, high soil

permeability or soils with high or low pH;

(b) Where there is proven occurrence of Sulphate Reducing Bacteria (SRB) or where soils have a

pH-value above 9.5 or below 4.0 (Reference J. Bowles, Foundation analysis and design, 1984,pp.227).

Precast monolithic piles or individual segments of jointed piles shall be classified as members in water

unless it is proven by geotechnical investigation that no part of the member is below the permanent water

table level.

5.2 CONCRETE PILES

5.2.1 Design Considerations

The minimum design requirements for reinforced and prestressed concrete piles shall be in accordance withthe requirements specified in AS 5100.

5.2.3 Concrete strength grade

The minimum concrete strength grade for reinforced and prestressed concrete piles shall be VR400/40.

5.2.2 Concrete cover

Minimum concrete cover shall comply with the requirements specified in AS 5100.5 Clause 4.10.3 for the

relevant exposure conditions, method of manufacture and concrete strength grade, except where specified

otherwise in Table 1 below.

The covers specified in Table 1 are based on tolerances of -0 mm and +5 mm for fixing of reinforcement as

per the requirements of VicRoads Specification Clause 620.27.

Exposure Classification as per AS 5100.5 Concrete Strength Grade

VR400/40 VR450/50

(a) For piles cast in rigid formwork and intense compaction *

B1 30mm 30mm

B2 45mm 35mm

C - 50mm

(b) For piles manufactured by spinning or rolling #

B1 25mm 25mm

B2 30mm 25mm

C - 35 mm

Table 1 Minimum cover to reinforcement


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6. AXIAL CAPACITY OF DRIVEN PILES

6.1 GENERAL

The design of driven piles shall comply with the requirements of AS 2159, AS 5100 except where specified

otherwise by this BTN, BTN 99/018 or VicRoads Specification for Roadworks and Bridgeworks.

Particular attention shall be given to complying with the requirements of AS 5100.3, Clause 11. The design

of driven pile foundations shall ensure that all ultimate and serviceability limit state requirements are

considered and specified.

The design shall include taking into consideration the uniformity of foundation material, soil-pile interaction,

negative skin friction and the use of appropriate geotechnical strength reduction factors when determining

pile design axial and flexural capacities and design toe levels.

6.2 SERVICEABILITY LOADS

Design for potential settlement of pile foundations shall include determining and specifying serviceabilitylimit state design pile loads, total and differential settlements.

6.3 ULTIMATE RESISTANCE

6.3.1 General

The designer shall calculate the characteristic ultimate limit state axial load capacity N, to be achieved in the

field, using the equation:-

N*= N.Φg

where

N* = ultimate limit state design axial load on the pile

N = characteristic ultimate limit state axial resistance of the pile (the pile test load to be

achieved in the field)

Φg = geotechnical strength reduction factor(s)

The designer shall determine value(s) of N based on appropriate partial geotechnical strength reduction

factors from Table 2 applicable to the proposed test method or pile driving and field measurements, the

potential use of pile joints and consideration of the results of geotechnical investigation.

6.3.2 Representative piles

The geotechnical strength reduction factor for the individual or representative piles shall be determined

from:-

Φg = Φ1.Φ4

This factor reflects the method of determining pile capacity, as listed in Table 2, and whether the pile

contains mechanical joints.

6.3.3 Represented piles

The geotechnical strength reduction factor for represented piles in the pile group shall be determined from:-

Φg = Φ2.Φ3.Φ4.Φ5


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Where the test results for a test pile (representative pile) are used to determine the capacity of another pile

(represented pile) additional variables are introduced. The pile driving parameters, the properties of the pile

and the ground conditions will all be different to some degree.

This results in a reduced confidence in the capacity determination for the represented piles and thus different

geotechnical strength reduction factors are required.

6.4 GEOTECHNICAL STRENGTH REDUCTION FACTORS FOR AXIAL RESISTANCE

The Pile Axial Test Loads shown on the drawings shall be calculated using appropriate geotechnical strength

reduction factors as follows:

Partial Geotechnical Strength Reduction Factors for Ultimate Limit State Value

Φ1 Representative Pile Factor

(a) Dynamic analysis of piles in cohesionless soils using pile drivingformula (e.g. Hiley formula)

(b) Dynamic analysis of piles in cohesive soils using pile driving formula

(e.g. Hiley formula)

(c) routine proof load tested

(d) static load tested to failure

(e) piles subjected to dynamic load tests using measured field parametersin a wave equation analysis with signal matching (e.g. CAPWAP)

(f) piles subjected to closed form dynamic solutions (e.g. Case method)

0.5

0.4

0.8

0.9

0.8

0.5

Φ2 Represented Pile Factor

(a) piles subjected to closed form dynamic solutions (e.g. Case method)correlated against static load tests or dynamic tests using measured

field parameters in a wave equation analysis (e.g. CAPWAP)(b) piles driven to a set correlated against static load tests or dynamic tests

using measured field parameters in a wave equation analysis (e.g.

CAPWAP)

0.75

0.7

Φ3* Geotechnical Variability Factor

(a) uniform soil profile and straight sided pile

(b) variation in soil profile with depth and/or variation in soil profileacross the site

1.0

0.85

Φ4 Concrete pile joint factor

(a) no pile extension

(b) piles extended and not redriven

(c) piles extended using approved mechanical joints and redriven

1.0

0.95

0.9

Φ5# Sample Size Factor

(a) 15% or more piles per group dynamically tested as representative piles

(b) 3% or less piles per group dynamically tested

1.0

0.85

* The value of Φ3 shall be determined by the designer in consultation with the geotechnical engineer.

# For intermediate values of Φ5 linear interpolation may be used.

Table 2 - Partial Geotechnical Strength Reduction Factors


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6.5 ACCEPTANCE CRITERIA FOR PILE DRIVING

PDA testing shall be used for all pile driving except where otherwise approved by VicRoads.

Use of the Hiley formula to prove pile resistance may be permitted by VicRoads for bridges of lowsignificance, where soil types are suitable and dynamic testing is not economically justifiable.

Reference shall be made to VicRoads Specification for Roadworks and Bridgeworks Section 605.

6.6 SCOUR AND PREBORING

Where piles are located in an area of potential scour the effects of both general and local scour shall be

allowed for in the design of the foundations.

Unless a rigorous analysis is used, a minimum local scour allowance of 1.0 m shall be used in addition to the

general scour allowance.

When conducting a pile test to determine the loss of resistance due to scour, preboring to below the estimated

scour depth shall be specified.

7. DESIGN BENDING MOMENT CAPACITY OF DRIVEN PILES

Calculation of ultimate limit state design bending moments (M*), shall include, in addition to determination

of other relevant design action effects, the following :

(i) The moment generated in a pile caused by the specified out-of-position tolerance and other

specified tolerance or measured displacement from the design location.

(ii) For piles with mechanical joints, a moment effect about each principal axis caused by the

combination of the design axial load (N*) and the offset resulting from an angle change of

1:100 at each joint.

(iii) A moment about each principal axis of N* times O.O5D where N* is the design axial load on

a cross-section and D is the overall width of the pile in the plane of the bending moment.

(iv) Pile end fixity, soil-pile interaction and similar as per AS 5100.3 Clause 11.4.1.

8. MECHANICAL JOINTS FOR CONCRETE PILES

All mechanical joints for precast reinforced concrete piles shall comply with the requirements of AS 5100.3

Clause 11.4 and BTN 99/018.

Mechanical joints shall not be located within 5 metres of the underside of pilecaps, or in aggressive

groundwater or soil, in accordance with Clause 3.1 of this BTN.

The designer shall specify the allowable range of depths for the mechanical joints on the drawings.


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9. HANDLING OF CONCRETE PILES

Piles shall be designed for handling stresses after adding 50% to the static load to allow for impact and shock

or for the static load and mould adhesion whichever is greater.

Pile stresses during driving shall comply with the requirements of VicRoads Specification Clause 605.04.

Reference is made to BTN 99/018 for required minimum concrete strengths for lifting and driving.

10. INFORMATION REQUIRED ON DRAWINGS

10.1 CONCRETE PILES

The following information shall be shown on the drawings for precast concrete piles:

(i) minimum characteristic concrete strength grade;

(ii) minimum concrete strength for lifting and handling;

(iii) minimum concrete strength for driving;

(iv) minimum cover and exposure classification

10.2 PILE TEST LOADS

The designer shall determine the pile ultimate limit state design loads based on structural requirements and

the site conditions. Where the designer knows the method of driving and the pile test procedure to be used

then these, together with the values of N and N* shall be shown on the drawings.

Alternatively, within the limitations specified in Clause 4 of this BTN, appropriate N values for use with the

Hiley formula may be specified on the drawings.

PILE AXIAL LOADS

PILE TEST LOAD N (kN)

PDA TESTING

PILE

LOCATION

ULTIMATE

LIMIT STATE

DESIGN AXIAL

LOAD / PILE

N* (kN)INDIVIDUAL or

REPRESENTATIVE

PILE

REPRESENTED

PILE

HILEY

FORMULA*

* Included where applicable (refer Clause 4 of this Technical Note)

Table 3 Pile Ultimate State Axial Design and Test Loads


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In the absence of better knowledge the designer shall calculate the values of N based on the following

assumed values for the partial geotechnical strength reduction factors:

Factor Assumed pile test conditionFactor

value

Φ1 (e) piles subjected to dynamic load tests using measured field parameters in

a wave equation analysis with signal matching (e.g. CAPWAP)

0.8

Φ2 (b) piles driven to a set correlated against static load tests or dynamic tests

using measured field parameters in a wave equation analysis (e.g.

CAPWAP)

0.7

Φ4 (a) no pile extension 1.0

Φ5 (a) 15% or more piles per group dynamically tested as representative piles 1.0

Table 4 Partial Geotechnical Strength Reduction Factors

The value of Φ3 shall be determined by the designer in consultation with the geotechnical engineer.

The design partial geotechnical strength reduction factors used to determine the pile test loading and the

assumptions made in selecting these factors shall also be shown on the drawings as specified in Table 5.

Representative

Pile

Represented

Pile

Partial

Factor

Single Spliced Single Spliced

Assumptions

Φ1 n/a n/a e.g. PDA CAPWAP analysis with signal

matching

Φ2 n/a n/a e.g. Set correlated against CAPWAP tests

Φ3 n/a n/a e.g. Uniform soil conditions

Φ4 1.0 1.0 e.g. no joints

Φ5 n/a n/a e.g. >15% dynamically tested

Table 5 Design Partial Geotechnical Strength Reduction Factors

10.3 PILE JOINT LOADS

Where the designer proposes to use mechanical pile joints the designer shall specify the allowable range of

reduced levels for the joint.

Mechanical joints shall be designed so that they provide a permanent connection between the pile lengths.

The strength of the joint, as specified by AS 5100.3, shall be not less than that of the lengths of pile being

joined.

PILE

LOCATION

JOINT

MINIMUM

REDUCED

LEVEL

(metres)

JOINT

MAXIMUM

REDUCED

LEVEL

(metres)

DESCRIPTION OF

ENVIRONMENTAL

AGGRESSIVENESS

Table 6 Pile Joints


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10.4 PILE TOE LEVELS

Pile toe levels shall be shown on the drawings, based on levels determined during design.

10.5 FOUNDATION SETTLEMENT

The values of serviceability limit state loads, settlements and differential settlements, used in the design,

shall be shown on the drawings.

10.6 CONCRETE PILE HANDLING DIAGRAMS

Diagrams specifying the allowable methods for handling the piles shall be included on the pile drawings.

11. REFERENCES

In compiling this document material has been adapted from the following references:-

PRESTRESSED CONCRETE INSTITUTE, Recommended Practice for Design, Manufacture and

Installation of Prestressed Concrete Piling, PCI Journal Vol. 38 No. 2, March/April 1993

ROADS AND TRAFFIC AUTHORITY OF NSW, QA Specification B51, Driven reinforced concrete piles,

1995

J. Bowles, Foundation analysis and design, 1984, pp.227

VicRoads Standard Specification for Roadworks and Bridgeworks

Australian Standards listed in Clause 2 above.

Approved June 2005

MIKE VEREYPRINCIPAL BRIDGE ENGINEERFor further information please contact:Principal Bridge Engineer3 Prospect Hill Road Camberwell Vic 3124Telephone: (03) 9811 8307Facsimile: (03) 9811 8329Email: [email protected] Tech Notes are subject to periodic review and may be superseded.


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VERSION: 2.1 DATE: July 2010 Page 1

DESIGN OF DECK JOINTS FOR ROAD BRIDGES 1. SCOPEThis document gives VicRoads’ requirements for the design and specification of deck joints forroad bridges in the state of Victoria and should be read in conjunction with AS5100 Bridge designand Section 660 of VicRoads Standard Specification.

The following technical note contains guidance relevant to this technical note:

2002/001 Reinforcement of deck joints

2. GENERAL Deck joints must comply with the following requirements:

• The design of deck joints must be in accordance with AS5100;

• There must be documented evidence of satisfactory performance of the joint system inservice conditions.

The bridge designer may include one or more deck joints that comply with the foregoingrequirements on the drawings from which the Contractor can make a selection. Should theContractor wish to use an alternative deck joint, it must submit full design details for the proposed

alternative to the Superintendent together with evidence of satisfactory performance. TheSuperintendent will then determine which joint system is to be adopted. Alternative joint systemsmust comply with the requirements stated above.

3. DESIGN REQUIREMENTSDeck joints and their associated anchorages shall be designed in accordance with therequirements of AS5100 and in particular with reference to AS5100.4 Clause 17.

Repair and replacement of deck joints are among the most common, costly and potentiallydangerous maintenance tasks. It is, therefore, essential to design and install these systems in amanner that minimises the future requirement for their maintenance.

3.1 GeneralThe requirements for noise, vibration, sealing, covering, corrosion resistance and accessibilityshall be in accordance with AS5100.4 Clause 17.3.1.

3.2 Design LoadsDeck joints and their anchorages shall be designed in accordance with the requirements ofAS5100.4 Clause 17.3.2.

3.3 FatigueDeck joints shall be designed for fatigue in accordance with the requirements of AS5100.4Clause 17.3.3.



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BTN 1999/002 Design of Deck Joints for Road Bridges


3.4 MovementsDeck joints shall be designed to accommodate Ultimate Limit State movements specified inAS5100.4 Clause 17.3.4. Components of movement including temperature, creep, shrinkage,prestress, and any additional construction or settlement movements likely to occur during thelife of the bridge should be considered. Ultimate load factors are given in AS5100.2. In cases

where the bridge joint cannot accommodate the full range of movement due to braking forces,the designer should ensure that once the available travel of the deck joint has been exhausted,the additional force due to braking can be resisted by passive earth pressure behind theabutment in conjunction with the approach slab where this is present.

The ultimate joint movement requirements and installation gap at a temperature of 20°C shallbe stated on the drawings.

3.5 Gap WidthRequirements for gap widths and definition of open joints are specified in AS5100.4 Clause17.3.5.

3.6 Anchorage of Deck JointsAnchorages for deck joints shall be designed in accordance with AS5100.4. Joints that includetensioned bolts shall be installed in accordance with Specification Section 660. The use ofretro-fitted bonded or mechanical anchors to hold-down deck joints is not permitted.

3.7 DrainageSealing of the deck joint is recommended to prevent the penetration of the joint by water anddebris which may cause staining and deterioration of the bridge superstructure andsubstructure. A drainage system should be provided with suitable connections to channel wateraway from the substructure. When deck joint drainage is provided, it should be designed tofacilitate inspection and maintenance.

3.8 InstallationDeck joints shall be designed and detailed to follow the bridge deck geometry including theprofile of kerbs and parapets where these are present. Specification Section 660 providesinstallation tolerances, and Clause 17.7 of AS5100.4 specifies a method of determining thebridge temperature at installation.

Anchorage failure is a common defect affecting deck-joints and is often attributed toinadequacy of the design or incorrect installation of the deck joint. In order to avoid defectsdue to incorrect installation, all deck joints shall be installed by the supplier in accordance withthe requirements of VicRoads Standard Specification Section 660.

3.9 MaintenanceThe supplier shall guarantee the serviceability of the joint for a minimum period of 10 yearsafter installation.

3.10 Joint SealantsFlexible continuous joint sealants and fillers and pourable sealants may be used on short spanbridges which have a range movement of less than 20 mm. The movement range in this caseis limited to + or – 25% of the installation width. The advantage of this type of deck joint is theseal can be repaired without replacement of the full length of seal.

Cellular neoprene compression seals can be used to replace these types of sealant.Compression seals may be used with a concrete or steel plate nosing – refer to 4.1 below.

Where a compression seal is used it should be continuous for the full length of the deck joint


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3.11 DetailingTo simplify detailing and fabrication of deck joints on skew bridges the alignment of the jointshould be made square where the joint crosses kerbs and parapets.

4. JOINT SYSTEMS

4.1 Compression Seal JointsCompression seal joints consist of a cellular neoprene seal held in position by a combination ofcompression and adhesion. The most common cause of failure of compression seals is loss ofadhesion resulting in the seal springing out of the recess. Compression seal joints are notsuitable for skew joints as the cellular insert does not accommodate racking movementsleading to a loss of adhesion.

All compression seals shall be installed in accordance with the supplier’s recommendationsusing a lubricant/adhesive which is compatible with the seal material.

Where the traffic volume is less than 150 vehicles per day, the vertical faces of the joint may be

formed by casting or saw-cutting the concrete. For heavier traffic volumes, steel plates are tobe used. The seal should be supported so that it is 5mm below the deck level to preventdamage by traffic.

Cellular compression seals come in a variety of sizes and configurations and each seal isdesigned to work within a prescribed movement range. The seal must be sufficiently robust toresist damage due to impact from stones and road debris. The walls of the seal may also fail asa result of fatigue caused by thermal movement leading to tearing or splitting. Joint suppliersshall provide a test certificate showing that the seal is made from an elastomer passingappropriate material test criteria.

4.2 Strip Seal JointsStrip seal joints consist of a continuous elastomeric membrane held in place by recesses insteel or aluminium alloy edge protection strips. The edge protection strips are bolted downusing fully tensioned high tensile bolts. This type of joint is relatively easy to install andmaintain and the edge strips can be raised or replaced if required.

The movement range of this type of joint is limited in accordance with AS5100 by the maximumallowable open gap width of 85mm. The minimum gap may be 0mm or 15mm depending onthe shape of the membrane. Joint suppliers shall provide a test certificate showing that theseal is made from elastomer passing appropriate material test criteria.

4.3 Finger Plate Joints

Finger plate joints consist of overlapping steel or aluminium fingers which allow longitudinalmovements of up to 300mm. Water passes freely through the joint and is collected in a troughor, alternatively, the joint may be fitted with a neoprene seal.Design of the fingers and anchor bolts should be in accordance with AS5100.4. The gap widthbetween fingers should be limited to a maximum of 35mm where bicycle access is allowed.Wide finger plate joints and joints located at turning lanes are not recommended unless asuitable permanent surface treatment is employed to prevent vehicles skidding on the exposedsteel.

4.4 Asphaltic Plug JointsThese joints may be suitable for replacement of existing deck joints or for short span bridgeshaving expansion movements of less than 20mm. The joint consists of a mixture of flexible

binders and aggregate constructed in place to form a flexible layer across the expansion gap.A flashing layer prevents the joint material from entering the gap and the joints is usually curedusing hot air. Serviceability of this type of joint is heavily dependent on quality control of


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materials and workmanship. Asphaltic plug joints are not suitable in locations where vehiclesmay perform stopping / turning movements or where there are low or very high / heavy trafficvolumes.

4.5 Modular JointsProvisions for modular deck joints are specified in AS5100.4 Clauses 17.3.2 and 17.6. Modular

or multi-seal joints are used on bridges having expansion movements in excess of the range offinger plate joints. These joints have internal bridging members which support the jointmodules that carry the wheel loads. Modular joints contain sliding surfaces which are subjectto wear and can become noisy if not correctly maintained.

In addition to the requirements of Clause 3.8 of this note, maintenance of modular joints shallbe carried out by the supplier in accordance with a service agreement which must beestablished as part of the Contract for supply of the joint.

Where it is practicable, access for maintenance of modular joints shall be provided from belowdeck level.

4.6 Poured Sealant JointsThe joint shall be a proprietary system and shall comprise a poured sealant together with acompatible nosing (header) material from the same supplier. Joints of this type shall complywith the requirements of AS5100.4 Clause 17 and in particular Clause 17.8.

5. CALCULATION OF JOINT MOVEMENT

The following steps are typical of the design process required to determine the movementrequirements of deck joints for a particular bridge.

STEP 1: On the basis of the bridge geometry, support conditions and constructionsequence, calculate the horizontal stiffness of all supports, including substructure and anystiffness of the deck joints being considered;

STEP 2: Determine the null-point or point of fixity of the bridge;

STEP 3: Determine the average age of the superstructure concrete at the time ofinstallation of the deck joints;

STEP 4: Calculate longitudinal and lateral movements due to temperature using thetemperature range from 20°C and the coefficient of thermal expansion given in AS5100.5Clause 6.1.6;

STEP 5: Calculate movement due to shrinkage in accordance with AS5100.5 Clause6.1.7 to determine values of k 1 for the appropriate environment and the average age of theconcrete and 30 years. Calculate the movement due to shrinkage using the net value of k 1;

STEP 6: Calculate movement due to creep in accordance with AS5100.5 Clause 6.1.8 todetermine values of k 2 and k 3 for the appropriate environment and the average age of theconcrete and 30 years;

STEP 7: Calculate the movement due to braking forces using the longitudinal forceobtained from AS5100.2 Clause 6.8.2 divided by the stiffness calculated in STEP 1;

STEP 8: Tabulate all joint movement components and ultimate load factors fromAS5100.2, and then calculate the worst combinations of ULS movements. Braking forcemovements do not need to be included in the total movement provided that the designer


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ensures that once the available travel of the deck joint has been exhausted, the additionalforce due to braking can be resisted by passive earth pressure behind the abutment;

STEP 9: Show the following on the drawings:

• Suitable alternative deck joints that have sufficient movement capacity;• Joint gap at 20°C;• Maximum joint gap;• Dimensions of deck joint profile including kerbs and parapet (if any).

MARIO FANTIN





Telephone: (03) 9811 8307

Facsimile: (03) 9811 8329


Bridge Tech Notes are subject to periodic review and may be superseded


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vicroads

DESIGN CRITERIA FOR NOISE BARRIERS 1. INTRODUCTION


This document sets out VicRoads requirements for the structural design of noise barriers.

The type (reflective or absorptive), material (timber, concrete, steel, polycarbonate, or other composite

materials) and location (including height) of noise barriers are usually determined by others prior to the

requirement for structural design.

Version 2.1 includes updated reference in Clause 3 (b) (ii) to the current wind code, AS/NZS 1170.2 – 2002.

2. GENERAL REQUIREMENTS

The following summarises general requirements for the physical properties, location and structural design

requirements for noise barriers.

2.1 PHYSICAL PROPERTIES

(a) General

General requirements for the physical properties of noise barrier materials are :

• Barriers should have a density of at least 15 kg/m2 of face area;

• Sound transmission loss through the barrier should be at least 30 dB(A) - to be verified by a

certificate of compliance from an approved laboratory, using AS1191 (Reference 1);

• Barriers should be constructed from durable materials having a minimum design life of 50

years, and be guaranteed for this period without deterioration of appearance or the

requirement for regular cleaning or painting;

• Barriers should have no holes or gaps , and should not be subject to the likelihood of this

occurring by natural causes such as rot, or attack by insects or vermin;

• All components should have physical durability with respect to exposure to sun (UV), water,

wind, air pollutants and temperature changes;

• All components should have low flame, fuel and smoke ratings;

• Barriers should be designed and built so that noise will not pass underneath them due to soil

erosion or settlement or digging animals;

•

Barrier materials should be resistant to vandalism such as impact damage, and componentsshould be readily replaceable;


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Design Criteria for Noise Barriers


• Barriers should be designed so that they will not reverberate or deflect excessively;

• Surface finishes on noise barriers should facilitate removal of graffiti in accordance with

VicRoads specification Section 685.

(b) Absorptive Barriers

In addition to the above general requirements, absorptive noise barriers should comply with the following

• Absorptive barriers should have a coefficient of absorption equal to or exceeding that shown

in the table below. In determining the coefficient of absorption, a representative sample of

the barrier having a surface area of not less than 12 square metres shall be used. A

certificate of compliance from an approved testing laboratory is required.

Frequency - Hz 125 250 500 1000 2000

Coefficient of absorption 0.70 0.80 0.90 0.90 0.80

• Sound absorptive materials should have acoustical durability consistent with the design life

of the barrier.

(c) Transparent Barriers

When considering use of transparent barriers, the following general requirements should be included :

• Potential reflection of sunlight or vehicle headlights;

• Resistance of the proposed material to scratching or discolouration with age;

• Possible maintenance requirements for dust removal;

• May be subject to bird strike;

• Panels should be mounted in rubber gaskets due to high coefficient of expansion;

• Nylon fibres may be incorporated in the material to increase strength.

2.2 LOCATION

General requirements for location of noise barriers are :

• Noise barriers may be freestanding, or located on top of earth mounds or traffic barriers;

• Where noise barriers are located on the edge of bridges over another road or pedestrian path,

the barrier and its supporting structure shall be designed to prevent panels or fragments of

panels from falling on to traffic or pedestrians as a result of vehicle impact (eg. a continuous

galvanised cable could be used to connect or support the panels);

• Where noise barriers are located on traffic barriers, they should have sufficient clearance to


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BTN 1999/006



avoid impact by high/wide vehicles, and noise barriers should not have components which

could spear impacting vehicles);

• Barriers should be easily accessible for construction, repair and maintenance;

•

Barriers on earth mounds or on batters should have a 1 metre minimum berm (in accordancewith the foundation design requirements discussed below) between the barrier and the top of

batter to provide for foundation stability (sliding and overturning), foundation protection,

prevention of gaps below the barrier, and access for construction and maintenance; spread

footings should be located no closer than 1.5 metres from the edge of a fill batter;

• Where barriers are located on earth mounds, the designer should specify the required

material properties of the fill and the level of compaction to provide the design assumptions

for settlement and strength. Typical VicRoads requirements are Type B fill, or better, placed

and compacted to a minimum dry density ratio of 98% Standard compaction.

3. STRUCTURAL DESIGN REQUIREMENTS

(a) General

Structural design standards shall be in accordance with AS 5100 and additional criteria for wind loading as

specified in Clause 3(b) below.

Designs based on use of materials not covered by AS 5100 shall be in accordance with relevant Australian

Standards.

(b) Wind Loading

Wind loads on barriers shall be calculated as specified in AS 5100.2 Clause 24 including reference to

AS/NZS 1170.2, using the net design wind pressure (pn) for both serviceability and ultimate limit states.

In AS1170.2 multipliers are used to adjust the design wind speed to match local terrain and topographic

conditions. Suitable multipliers should be selected in accordance with :

(i) Site conditions during the life of the structure. Site conditions leading to the highest

design wind pressure shall be assumed; for example, buildings and trees in the vicinity may

not always be present.

(ii) Appendix D2 of AS/NZS 1170.2 Design should allow for increased wind load near the

ends of noise barriers in accordance with this Appendix. For this reason, considerationshould be given to reducing the height of noise barriers at the ends to reduce wind loads and

improve appearance

(c)

Foundation Design

Noise barriers may be supported on foundations comprising either spread footings, driven precast concrete

piles or steel piles, or bored cast-in-place piles.

Noise barrier foundations should be checked for both serviceability and ultimate limit states, and designed to

limit deflections to specified tolerances based on the limits recommended below.

Where the barrier foundation is located on disturbed material, such as earth mounds, both initial and longterm soil parameters should be used in the design of the foundations.


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For serviceability limit state, long term settlement and lateral movement of the barrier due to causes such as

embankment consolidation, should be considered together with serviceability loads such as wind. For

barriers at the edge of an embankment, foundation design should take into account the likely foundation

movement. The following tolerances on total barrier deflection are recommended where appearance is

considered important :

Straightness in plan - 1 in 200 over a barrier length of 10 metres

Straightness in elevation - 1 in 300 over a barrier length of 10 metres

Rotation from the vertical - 1 in 200 over the full barrier height

These tolerances are advisory, and may be exceeded in particular circumstances; for example, alignment may

have a greater tolerance for a curved noise barrier.

The designer should specify the following on the drawings or in the specification:

• The required material properties and level of compaction of fill for earth mounds (when

noise barriers are mounted on earth mounds);

•

The required construction tolerances.

4. REFERENCES

(1) AS 1191 – Acoustics – Method for laboratory measurement of airborne sound transmission

loss of building partitions

(2)

AS 5100 Bridge Design 2004

(3)

AS/NZS 1170.2 Loading Code - Part 2, Wind Loads

Approved June 2006

MIKE VEREY


Contact Officers

Author: David Payne




Telephone: (03) 9811 8307

Facsimile: (03) 9811 8329




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vicroads

DETAILING OF REINFORCED SOIL FACING PANELS

1. SCOPE

This Technical Note provides guidelines for detailing of precast concrete facing panels for

Reinforced Soil Structures (RSS).

These guidelines do not apply to alternative facing systems for RSS such as masonry blockwork,

geotextiles or gabions.

2. GENERAL

Reinforced Soil Structures considered in this Technical Note consist of a composite system of

compacted select fill and reinforcing material with precast concrete facing panels. RSS are

designed, supplied and erected by specialist contractors in accordance with the geometric

requirements of the particular site, and Section 682 of VicRoads Standard Specification which

specifies the requirements for the design, supply of materials including select fill, manufacture and

construction.

3. VERSION 1.1

Version 1.1 of this Technical Note includes reference to AS 5100.

4. CONCRETE FACING PANELS

Concrete facing panels should consist of reinforced concrete deigned and detailed in accordance

with the requirements of AS 5100 and VicRoads Standard Specification Section 610 – Structural

Concrete, Section 620 – Precast Concrete Units and Section 682 – Reinforced Soil Structures.

Design and detailing requirements for wall facing panels are summarised below :

• To control cracking due to shrinkage and temperature, a minimum reinforcement of 500mm

2 per metre in each of two directions at right angles to each other and located at mid-

depth of the panels. Note that this requirement has been adopted despite the serviceability

requirement in AS 5100 Clause 2.8 for thickness greater than 150 mm for 500 mm2 per

metre in each face.

• Sufficient reinforcement to provide strength for handling, transport, storage, placing and

loading due to soil pressure including any future extension of the retaining wall.

•

Concrete cover to reinforcement in accordance with AS 5100.• Embedded fittings with suitable corrosion protection (minimum design life of 100 years) for

connection to the soil reinforcing elements.



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Detailing of Reinforced Soil Facing Panels


• Minimum concrete grade of VR330/32.

• Surface finish on exposed faces of Class 3, unless a special finish is specified.

• Method of connecting panels to prevent relative displacement normal to the wall face.

• Provision of chamfers on exposed edges to prevent spalling during handling.

5. REFERENCES

AS 5100 – Bridge Design 2004

VicRoads Standard Specification Section 610 – Structural Concrete

VicRoads Standard Specification Section 620 – Precast Concrete Units

VicRoads Standard Specification Section 682 – Reinforced Soil Structures

Approved June 2005

MIKE VEREY





Telephone: (03) 9811 8307

Facsimile: (03) 9811 8329




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vicroads

DESIGN CRITERIA FOR LARGE RECTANGULAR

PRECAST R.C. CULVERT UNITS

1. SCOPE

This Technical Note defines the design criteria for the design of large rectangular reinforced concrete culvert units (from 1500 mm span up to and including 4200 mm span and 4200 mm height) and link slabs used as roadstructures in the State of Victoria.

Designers should note that culvert units may be designed for the passage of water, vehicles, pedestrians or animals,and should be designed with appropriate clearances, finishes and lighting where required by VicRoads.

This Technical Note does not cover the design nor manufacture of smaller “box culverts” which are covered byAS1597 Part 1 and VicRoads Specification Section 619, and are accepted on the basis of proof loading.

Bridge Technical Note1999/010

2. STANDARDS

a. Reference Documents

The structural design of precast culvert units shall comply with the following reference documents:

VicRoads Standard Specifications

Section 610 - Structural concrete.Section 611 - Steel reinforcement.Section 620 - Precast concrete units.Section 626 - Installation of precast concrete crown unit culverts.

Australian Standards

AS 5100 (2004) - Bridge designAS 1597 Part 2 - Precast reinforced concrete box culverts; Part 2: Large culverts.AS/NZS 4680 - Hot-dip galvanized (zinc) coatings on fabricated ferrous articles.

b. Precedence of standards

Where conflict exists between requirements of the reference documents then the documents shall be observedin the following order, highest precedence first:

i. This documentii. VicRoads Design Technical Notesiii. VicRoads Standard Specificationsiv. AS 5100 (2004) – Bridge designv. Other Australian Standards

VERSION: 1.1 DATE: January 2006 Page 1


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BTN 1999/010

Design of precast culvert Units


3. MATERIAL REQUIREMENTS

a. Concrete

i.

General

Concrete shall be in accordance with VicRoads Standard Specification, Section 610. The minimumConcrete Grade shall be VR400/40.

ii. Durability

The minimum exposure classification for standard culvert units shall be B1.Precast culvert units designed for use in livestock underpasses shall be designed for exposureclassification C.

iii. Cover

The minimum covers specified in AS 1597.2, Table 2.4 shall be used.The tolerance on cover shall be as specified in AS 1597.2 (ie: –0 +10mm).

b. Steel Reinforcement

Steel reinforcement shall be in accordance with VicRoads Standard Specification, Section 611.

c. Soil properties

For design purposes, soil adjacent to culverts shall be assumed to be free draining granular fill with an angleof internal friction not greater than 30 degrees and a gravity force per unit volume of not less than 20 kN/m3.

d. Foundation material

Foundation material properties used for the design of “U” shape and one-piece culverts for a particular siteshall be determined from a suitable geotechnical investigation.

Where a geotechnical investigation has not been undertaken or for standard culvert unit design intended tocover the full range of possible foundation materials, the foundation material shall be assumed to be no betterthan non-reactive soft clay.

4. DESIGN REQUIREMENTS

a. Designer

Culvert units shall be designed by a qualified structural engineer having:

i. Relevant experience in the design of culvert units.

ii. Design and verification procedures complying with the requirements of AS/NZS ISO 9001 (DesignControl).

iii. Professional indemnity insurance and insurance of employees in accordance with the requirements ofClause 1.13 of VicRoads Consultancy Agreement (July 1997). Professional indemnity insurance shall befor an amount of not less than $10,000,000 and shall be maintained during the currency of the design andfor a period of 6 years after installation of the culvert units.

b. Design lifeThe basic design life of standard culvert units approved for use as road structures shall be 100 years, inaccordance with AS 5100.1.


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c. Design loads

i. General

Culvert units shall be designed using the requirements and design loads specified in AS 1597.2, Section 3except that for traffic loads, the A160 and M1600 traffic loads including dynamic load allowance, asdescribed below, shall be used.

ii. Traffic Loads, A160 and M1600 Loads

Culvert units shall be designed for the A160 Axle Load and M1600 moving traffic load, detailed in AS5100.2. The dynamic load allowance factor as specified in AS 5100 with appropriate load factors shall beused for these loads. The methods described in AS 1597.2, Clause 3.2.2.6.1 and Clause 3.2.2.7 (c) may

be used to determine vertical and horizontal pressures due to these loads.

iii. Site specific loads

Culvert units shall be designed for site specific loads such as barrier loading on the end walls, wingwallloads and/or settlement of foundations.

iv. Handling

Provision shall be made for lifting and handling the culvert units in accordance with AS 5100 and AS1597 Part 2, Clause 2.13 and Clause 3.2.5.

Lifting devices and methods of handling precast units shall in accordance with designer’s requirements.

v. Construction Loads

Construction loads on culverts shall be in accordance with VicRoads Standard Specifications, Clause626.10, or as specified.

d. Strength

The theoretical design strength φR u shall be determined in accordance with AS 5100.5. The critical section forshear shall be taken as shown in AS 1597 Part 2, Figure 3.2.

e. Serviceability

Serviceability parameters shall be calculated in accordance with AS 5100.5. However the minimumdistribution reinforcement shall be in accordance with AS 1597 Part 2, Clause 3.5.

f. Reinforcement Detailing

Reinforcement detailing shall be in accordance with AS 1597 Part 2, Clause 3.5.

g. Hydraulic requirements

Where culverts are designed for conveying water, the culvert walls shall present a smooth continuous surfaceto the water flow to prevent entrapment of debris.

h. Settlement

Precast base slabs and one piece culvert units shall not be used, except where bases are connected by means ofshear keys designed to prevent differential settlement between adjacent units. For hydraulic structures, shear

keys in the base slab shall be sealed to prevent leakage.


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5. LOAD TESTING FOR DESIGN

VicRoads does not accept the simple approach of load testing 1 in 20 culverts to prove the design of LargeCulverts. However, a statistical failure load test method can be used for empirical assessment of the designstrengths in accordance with AS1597.2 Clause 4.7, provided that VicRoads receives copies of the drawings of eachculvert unit (refer to clause on Documentation). These drawings will be stamped as confidential documents andwill only be used by VicRoads in the case of future modifications or re-use of the culvert units; for example,widening or attachment of endwalls or services.

The basic test loads specified in Tables J1 and J2 of AS1597.2, Appendix J for standard sizes shall be deemed toconform to the design loads in AS 5100. Where basic test loads other than those in Appendix J are used, the basictest loads used shall be supported by design calculations.

6. DOCUMENTATION

a. Information supplied to VicRoads shall include:

i. Two complete sets of final drawings.ii. The method of culvert installation inasmuch as it affects the design of the units.

b. Design calculations

A copy of the calculations used for the design of the culvert units shall be maintained by the designer, inaccordance with AS/NZS 9001, for a period of not less than 7 years, and shall be made available to VicRoadsif requested. Design records shall include calculations produced during the design and verification process.

c. Test Load Results

Where Failure Load Testing for design is used the results of all Load Testing shall be made available toVicRoads if requested. If basic test loads other than those in Appendix J are used, the basic test loads usedshall be supported by design calculations, which also shall be available to VicRoads if requested.

When designs are based on prior Failure Load testing, records shall be provided of routine sampling andtesting in accordance with Section 5 of AS1597.2 to show that the strength enhancement factors for routinetesting comply with factors obtained in prototype testing.

d. Drawings

Information shown on the drawings shall include:i. Complete dimensions including reinforcement details and tolerances.ii. Installation details for multi-cell culverts.

iii. Concrete exposure classification.iv. Standard and grade of materials used in the manufacture of the units.v. Assumed foundation soil type.vi. Foundation serviceability and ultimate limit state design-bearing pressures.vii. Traffic design loads including Dynamic Load Allowance.viii. Assumed dead load, live load and soil factors.ix. Design fill depth over the culvert units.x. Provisions for lifting of the culvert units.xi. Culvert unit volume and mass.

7. CULVERT CLASSES

It should be noted that the culvert classes specified in AS1597.2 are for a fill height range. The minimum designrequirement for culverts for VicRoads use is Class 2-A. Units shall be marked in accordance with AS1597.2Clause 2.16.


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Approved January 2006

MIKE VEREYPRINCIPAL BRIDGE ENGINEER

Contact Officers

Author: Dennis EastwoodFor further information please contact:Principal Bridge Engineer3 Prospect Hill Road Camberwell Vic 3124

Telephone: (03) 9811 8307Facsimile: (03) 9811 8329Email: [email protected] Tech Notes are subject to periodic review and may be superseded.Bridge Design File No


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vicroads

MANUFACTURING DETAILS FOR PRECASTCONCRETE PILES

1. SCOPE

This document provides background information for issues regarding the manufacture of precast concrete

piles.

VicRoads requirements for design and testing of precast concrete piles (and steel piles) are given in BridgeTechnical Note 1996/001 – ‘Design Parameters for Driven Piles’.

2. STANDARDS

This Technical Note is based on the requirements of relevant Australian standards, including but not limited

to the (current edition) of the following:

AS 1012-PART9

AS/NZS 1554-PART 1

AS/NZS 1554-PART 3

AS/NZS 1554-PART 5

AS 2159

AS 3678

AS 3679

AS/NZS 4671

AS 1311

AS 5100

VicRoads

Method for the Determination of the Compressive Strength of Concrete

Structural Steel Welding - Welding of Steel Structures

Structural Steel Welding - Welding of Reinforcing Steel

Structural Steel Welding - Welding of Steel Structures Subject to high

levels of Fatigue Loading

Piling - Design and Installation

Structural Steel - Hot-rolled Plates, Floor Plates and Slabs

Structural Steel

Steel reinforcing materials

Steel tendons for prestressed concrete -7 wire stress-relieved steel strand

Bridge Design

Standard Specification for Roadworks and Bridgeworks



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Manufacturing Details of Precast Concrete Piles


Precast concrete piles shall be supplied in accordance with the contract drawings, VicRoads Specification

and in accordance with ‘industry standards’ approved by VicRoads.

Piles shall be designed in accordance with the requirements of AS 2159 except where specified otherwise in

AS5100 and BTN 96/001.

All welding of reinforcement shall be in accordance with the requirements of AS/NZS 1554.3.

When considering Contractor’s submissions for changes which are based on previous drawings or

specifications, contract administrators should ensure that all circumstances are similar. The following factors

can change from a previous job :-

a) revised standards or specifications, and/ or

b) site conditions, including design loads, geotechnical conditions, and exposure classification.

Changes to specified details shall only be undertaken with the agreement of the designer.

3. MANUFACTURING ISSUES

This clause provides guidance on VicRoads procedures and practices relevant to common manufacturingissues.

3.1 Concrete strength

• Concrete strength for piles shall be not less than the value given in Table 1 of BTN 96/001 for the

relevant exposure classification.

• Contract administrators should ensure that the Contractor’s proposed concrete mix complies with the

strength requirements and VicRoads specification Section 610 mix requirements.

• The concrete strength requirements for precast piles are often determined by the loads for lifting or

handling of the piles. High early strength may be required by the Contractor to allow removal of thepiles from the forms.

3.2. Concrete temperature

• Clause 610.17 (a) of VicRoads Specification requires the temperature of the concrete before placing

to be between 10°C and 32°C, and Clause 610.22 requires a maximum temperature differential

across the pile of 20°C during curing.

3.3. Curing

• Curing requirements are given in VicRoads specification Section 610 – Structural Concrete.

• Contract administrators should note that durability of the concrete is a function of not only the

concrete mix, but also the way in which the pile is cured. An increase in the concrete strength grade

will provide higher early strength and allow the manufacturer to lift the pile earlier, but higher

strength does not reduce the specified requirements for curing.

3.4. Concrete strength at lifting

• Clause 620.03 of VicRoads specification requires a minimum concrete strength of 20 MPa for lifting

precast concrete units from forms.


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3.5. Concrete age and strength at driving

• Clause 605.08 of VicRoads specification requires that piles shall not be driven until the specified

design concrete strength has achieved, and not less than 14 days after casting when moist curing of

all exposed surfaces is used, or 7 days minimum after casting for steam curing.

•

Contract administrators should note that both the minimum strength and minimum age requirements

must be complied with to ensure concrete durability.

3.6. Concrete surface finish

• Clause 620.02 of VicRoads specification requires all precast concrete piles to have a Class 1 surface

finish and be manufactured using steel forms, ‘.. except where otherwise approved by the

Superintendent.’

• For square piles, an acceptable hand finished surface of the pile similar to the formed surfaces can be

produced using either a steel trowel or wood float.

• VicRoads’ practice is to accept square piles with either a steel trowelled or wood float surface

provided that surface finish meets the requirements of VicRoads specification Section 620.

3.7. Precast square piles without chamfers

• Clause 11.4.2.1 of AS 5100.3 specifies that ‘any square corners (of precast reinforced concrete piles)

shall have a 25 mm chamfer …’

• The purpose of the chamfers is to prevent damage to the corners of the piles during handling, and to

minimise stress concentrations during driving.

•

VicRoads’ practice is to accept piles without chamfers provided that –

a) the piles will not be exposed to view, eg. they are unacceptable for a pile bent pier.

b) the piles are not in exposure environments U or C (refer to AS 5100.5 Clause 4.3 for definitions

of exposure environments), eg. Old tip sites, salt-rich arid areas, tidal or splash zones.

c) there is no risk of damage to the piles during driving due to the presence of rock floaters or

similar (e.g. gravels, limestone layers) in the soil.

d) care is taken in handling the piles to prevent damage to the corners. All piles should be inspected

prior to driving and any damage immediately repaired or the piles rejected.

3.8. Reinforcement

• When not governed by design or other loading such as handling, minimum reinforcement for RC and

PSC piles shall comply with AS 5100.3 Clause 11.4.2.

3.9. Equivalent reinforcement

• Where anchor bars on mechanical joints interfere with longitudinal reinforcement, alternative

arrangements, that provide equivalent longitudinal reinforcement, may be used.


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3.10. Details of lateral ties and helices

• AS 5100.5 Clause 10.7.3.4 specifies details for anchorage and splicing of rectangular and circular

ties and helices.

3.11. Pile toe protection

• Unless piles are to be driven wholly in soft soils, all toes shall be protected to ensure that piles can be

driven through hard materials without damage.

• The type of pile toe protection shall be suitable for the job specific foundation conditions. Where

there is doubt about the suitability of the Contractor’s proposed pile toe protection details, contract

administrators should refer questions to Geopave or the Principal Bridge Engineer’s section.

• Pile protection fittings shall be made ‘integral with the pile’ by using anchor bars welded to these

fittings.

3.12. Pile driving ring or head band

• Pile driving rings shall be used to prevent splitting or bursting of the top of reinforced concrete piles

during driving, as required by AS 5100.3 Clause 11.4.2.1..

• Pile driving rings or head bands shall be detailed using full penetration butt welds and backing

plates.

3.13. Mechanical joints

• AS 5100.3 Clause 11.4.2 requires mechanical joints to provide a permanent joint with a strength ‘..

not less than that of the lengths of pile being joined’.

• Design of mechanical joints shall comply with the durability requirements of AS 5100.3 Clauses 9.3

and 9.4.

• Mechanical joints shall be located at the level and within the soil strata assumed by the designer for

both strength and durability consideratio