Robin Report1

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SUMMER TRAINING REPORT(11.06.2012-20.07.2012)

(LARSEN & TOUBRO CONSTRUCTIONS)

Construction of Air Traffic Control Tower (ATC) &

Associated Works

DCRUST, Murthal

SUBMITTED BY:-ROBIN KUKREJA

ROLL NO. :- 0909044

FINAL YEAR B.Tech (Civil Engineering)


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ACKNOWLEDGEMENT

I would like to take this opportunity to thank Larsen & Toubro

Limited for giving me an opportunity to do my internship with them.

I express my sincere thanks and gratitude towards Mr.Rakesh Kumar

Singh (Project Manager) and Ms.Pooja Mishra (Assistant Planning

Manager) who guided me and provided valuable inputs and insights

throughout the internship.

I would also like to express my special gratitude and thanks toMr.ShushilKumar (Sr. Engineer) and other site engineers for giving me

such attention and time.

Mr. Ashim Gupta,for familiarizing me with the processes and details of

site work

My thanks and appreciation also goes to my colleagues for their special

co-operation and people who have willingly helped me out with their

abilities.


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CONTENT

1. Introduction 42.Air traffic control tower model picture 63.Construction: ATC Tower 8-114.Construction: ACC and TBB 12-165.Earth work 17-196.Waterproofing 20-237.Reinforcement 23-27

a)Re baring8.Concreting 28-359. Injection grouting 36-39

10. Brick work 40-4311. Safety precaution 44


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INTRODUCTION

During Summer vacations after completed3rd

year in Deenbandhu

Chotu Ram Engineering College, Murthal,Sonipat, I did six week

internship (from 11.06.2012 to 20.07.2012) wit LARSEN & TOUBRO

LIMITED (ECC DIVISION).

Project: ATC Tower & Associated Works at T3-DIAL, IGI Airport, New

Delhi

Project detail:- New Control Tower Construction consists of Air

Traffic Control Tower (ATC), Area Control Centre Building (ACC), Tower

Base Building (TBB) & Link Bridge

1.Client Delhi International Airport Ltd.2.Contractor L&T (ECC Division B&F BU)3.Architect HOK International, London4.Structural Consultant BuroHappold UK, Taylor Devices

India Pvt. Ltd.

5.Area Control Centre BUA 25,185 Sq.m. (approx.); B+4 Floor6.Tower Base Building BUA 9,375 Sq.m. (approx.); 4 Floor7.ATC Tower BUA 2154 Sq.m. (102 m Ht.)This tower is 3rd

highest ATC tower of the world & highest ATC tower of the

Asia. 26 Floors

To manage site requirements below mentioned area are covered:Steel

yard, Form work yard, Batching Plant & Basic Infrastructure Facilities.


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The new Air Traffic Control Tower at Delhis Indra Gandhi International

Airport will be the countrys tallest ATC once constructed .It will stand

102m tall with 26 controller postion with a 360-degree view at the

visual control room and 12 ground controller positions at operationallevel. The tower will employ the Tuned Mass Damper (TMD) technology,

first of its kind in India, to reduce the building sway due to lateral forces

such as wind and earthquake forces.

The ATC tower has two associated building for control and functionthe

Area Control Centre (ACC) and the Tower Base Building (TBB).These

buildings are G+4 structures. These buildings will house the equipments

required for air traffic control.

The ATC Tower is scheduled for completion in a time period of 22

months and commissioned in October 2013. It will be fully functional by

2014. The associated works-ACC and TBB- are scheduled for completion

in 12 months and commissioned by 1st

Janaury 2013


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AIR TRAFFIC CONTROL TOWER PROJECT

MODEL PICTURE


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CONSTRUCTION

AREA TRAFFIC CONTROL TOWER(ATCC)

AREA CONTROL CENTRE(ACC)

TOWER BASE BUILDING(TBB)


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AIR TRAFFIC CONTROL TOWER

The ATC Tower ,once constructed ,will be the tallest ATC in India with a

height of 102m. Also,it will be the 7th

tallest ATC Tower in the world.It

will consist of 26 floors and be made of Self Compacting Concrete (SCC)

of varying grades. The facing of the tower will be in Glass Reinforced

Concrete (GRC).

The construction sequence of the ATCTower are furnished below:

PILLING DETAILS

REINFORCEMENT CONCRETING

1.PILING DETAILS:

The type of foundation selected for the Air Traffic Control Tower on the

basis of Geotechnical Investigation Report was Bored Cast In-Situ

Friction Piles. The geotechnical report classified the soil as Sandy Silt

Soil with a CBR value of 9-13%

A)FONDATION DETAILS

The details of the foundation are:

PILES

Diameter of Pile :1500mm

Depth of Piles : 23.5m

No. of Concrete: M30(SCC)

PILE CAP


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Area of Pile Cap :650.301 sqm

Height : 3m

Grade of Concrete :M40(SCC)

B) PROCEDURE FOR FOUNDATION WORKS

a)Procedure for Piling Works

The procedure for piling works is essentially a two component

procedure .It includes :

Pile Load Test

Piling WorkPILE LOAD TEST

The Pile Load Test was conduted as described below


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TEST PROCEDURE as per IS 2911(Part-4)-1985

1.Preparation of Pile HeadThe top of pille head shall be exposed and top of concrete

chipped off upto the required test level .The top of the pile head

shall be finished smooth and level with non-shrink grout material.

Two bearing plates of suitable size and thickness 60mm shall be

placed one above the other on the of the pile for the jack to rest.

2.Kent Ledge ArrangementA Platform shall be made of steel joist with primary and

secondary girders . The Centre of Gravity (C.G) of this platform

should concide with the C.G of the pile head .Dead weights such

as concrete block or sand bags should be placed aove the

platform to obtain the necessary reaction.The reaction available

should be 25% more than the test load proposed.

3. Intial Load Tests on Test PilesThe intial pile is tested upto 3 times the design load or up to

failure whichever occurs earlier .The test is carried out by applyinga series of vertical downward incremental loads, each increment

being about 20% of the design load. At each load increment ,the

pile deflection shall be observed accurate to 0.02 mm at an

interval upto a time when the rate of settlement reduces to either

0.1 mm in first 60 minutes or 120 minutes ,whichever occurs first.

The final load shall be maintained for 24 hours and reading

recorded for 5,10,15,30,60,90,120 minutes and at every hour till24 hour completes.


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ii) Procedure for Mass Concreting of the Pile cap of ATC Tower

Dimension of Pile Cap and Type of Concrete:

Area : 650.301

Height: 3m

Total Quantity of Concrete :1780 cum

Grade of Concrete:M40(SCC)

Placement Temprature:550mm(min)

Mock Up Test for Pile Cap:

A mock-up test was conducted in the laboratory prior to the actual

concrete placement at site.The mock-up was conducted to determine

the temperature changes in the mass concrete due to heat of hydration

process.

Scope: To find the temperature changes in the concrete due to heat of

hydration process.

Concrete: 3.0 cum fresh concrete of Grade 40(SCC) was cast in a cube

of dimensions 1.5m x 1.5m x 1.35m

Insulations:100mm thick Polyurethane foam insulation materials were

placed on the inner sides of the formwork.

Reinforcements: Reinforcements of diameter 10mm@100mm c/c

spacing were placed at top buttom and sides.

Placement of Thermocouples: The thermocouples are placed as shown

in the diagram:


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AREA CONTROL CENTRE (ACC) & TOWER

BASE BUILDING(TBB)

Construction sequence in ACC and TBB

1 SUBSTRUCTURE:

a)EARTHWORK

Excavation Sand Filling PCC Water Proofing Screed(50mm)b)RAFT

Reinforcement Shuttering Concreting

2. SUPERSTRUCTURE:

a)VERTICAL: Retaining Walls,Columns,Shear Walls and Staircases


b)HORIZONTAL : Beams & Slabs



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1.SUBSTRUCTURE

a)EATHWORK

Excavation:The excavation work commences after settingout of levels by the surveyor. The depth to be excavated

is determined by the design consideration . For example :

In the basement of the ACC building 6m of soil was

excavated for basement construction.

Sand Filling:Sand Filling was done in expansion jointbetween the upper raft and basement raft of ACC and

TBB . The sand used for sand fillng is obtained from

suitable source and compacted to required density before

fillng .

PCC: After sand filling,a layer of Plain Cement Concrete(PCC) 1:6:12 is applied .The grade of this concrete is M10

Water Proofing: The Material used for water proofing isPolyurethane. It is a derivative of bituminous water

proofing and is applied on the retaining wall between the

basement raft and upper raft of ACC

Screed: A floor usually a cementitous material made froma 1:3 or 1:4:5 ratio of cement to sharp sand.It may be

apllied onto either a solid in-situ concrete ground floor

slab or onto a precast concrete floor unit. The screed may

be directly bonded to the base ,with a minimum thickness

of 40mm, laid bounded onto a suitable damp proofmembrane ,which is placed over the slab , with a

minimum thickness of 50mm

2.SUPERSTRUCTURE


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A) VERTICAL

Columns Shear Wall

i) Columns: Reinforcement

Columns, the vertical members in RC building

contain two types of steel reinforcement, namely

a)Long straight bars placed vertically along the length.b)Closed loops of small diameter steel bars placed horizontally

at regular intervals along its full length

Design strategy of columns as per IS 456-2000 and IS 13920-

1993

(a)Closely spaced ties must be provided at the two ends of thecolumn over a length not less than larger dimension of the

column, one-sixth the column height or 450mm.

(b) Over the distance specified in item (a) above and below abeam-column junction, the vertical spacing of ties in columns

should not exceed D/4 for where D is the smallest dimension of

the column (e.g.: in rectangular column, D is the length of the

small side). This spacing need not be less than 75mm nor more

than 100mm. At other locations, ties are spaced as percalculations but not more than D/2.

(c)The length of tie beyond the 1350 bends must be at least 10 timesdiameter of steel bar used to make the closed tie;this extension

beyond the bend should not be less than 75mm.


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Lapping of Vertical BarsIn the construction of RC buildings, due to limitation in available length

of bars and due to constraints in construction, there are numerousoccasions when columns bars have to be joined. A simple way of

achieving this is by overlapping the two bars over at least a minimum

specified length, called lap length. The lap length depends on type of

reinforcement and concrete. For ordinary situations, it is about 50

times bar diameter. Furthur, IS13920-1993 prescribes that the lap

length would be largest only in the middle half of column and not near

its top or bottom ends. Also, only half the vertical bars in column are to

be lapped at a time in any storey . Furthur, when laps are provided, tiesmust be provided along the length of the lap at spacing not more than

150mm.

ShutteringShuttering of the columns is checked with the help of plumb

bobs.The perpendicular distance between the plunb thread and

formwork surface is measured at the top and bottom to ensure

vertically of the column formwork

Concreting:Concrete of grade M40 SCC is used for the columns .The concrete is

placed using boom placers and then vibrated using vibrators of

diameter 40mm or 60mm as applicable.The shuttering of columns isremoved after a period of 24 hours after which the concrete is

cured till it attain its required strength.


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ii)Shear Walls

Reinforced concrete (RC) building often have vertical plate-like RC wallsin addition to slabs ,beams and columns .these walls generally at

foundation level and are continous throughout the building height.

Therir thickness can be as low as 150mm,or as high as 400mm in high

rise buildings. Shear wall are provided along both length and width of

building shear walls are alike vertically oriented beams that carry

earthquake load downwards to foundation

REINFOCEMENT IN SHEAR WALLS

Stell reinforcing bars are to be provided in walls in regularly spaced

vertical and horizontal grids. The vertical and horizontal reinforcement

in the wall can be placed in one or two parallel layers called

curtains.horizntal reinforcement need to be anchored to the walls the

min. area of reinforcing steel to be provided is .0025 times the cross

sectional area, along each of the horizontal and vertical directions .This

vertical reinforcement should be distributed uniformly across the wall

cross section.


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EARTHWORK

INTRODUCTION: -Earth work is the works related to soil.Which consist

excavation, earthfilling.

EQUIPMENTS:-

1.Roller, Plate Compactor & hand rammer2.Dumper, trolley3.Auto level4.NDG (Nuclear Density Gauge)MATERIAL:-

1.Yamuna Sand2.Excavated SoilEXPECTED QUANTITY:-99,036 cu.m

EXCAVATION:-

Excavation in different area of the site

Excavation shall be taken to the width of lowest step of footing or the

pile caps (required level) and the sides shall be left in slope where the

nature of the soil allow it for safety purpose.

DEWATERING AND PROTECION:-Where water is met with in excavation due to stream flow,

seepage,springs,rain or other reasons. Take adequate measures such as

bailing,pumping,construction of diversion channels, drainage

channels,bunds,cofferdams and other necessary works to keep the


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foundation trenches/ pits dry when so required and to keep the green

concrete against damage by erosion or sudden rise of water level.

No pumping shall be permitted during the placing of concrete or for any

period of atleast 24 hours thereafter.

PREPRATION OF FOUNDATION:-

The bottom of the foundation shall be leveled both longitudinally and

transversally or stepped. Before the footing is laid, the surface shall be

slightly watered and rammed.

If there is any slips or blows in the excavation, these shall be removed.

BACKFILLING:-

Backfilling is done with Yamuna sand.


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EARTHFILLING

GENERAL: - Filling is done with excavated earth soil. It is free from

salts, organic matter, black cotton soil and combustible material. So it

can be easily used for filling at the site.

FILLING IN PLINTH:- Filling is done in layer of 25 cm, watered &

consolidated by ramming with iron rammers weighing 7 to 8 kg, and

having base 20 cm. dia. .

When the filling reaches the finished level, surface is kept flooded with

water for 24 hours, allowed to dry and then rammed and consolidate,

in order to avoid settlement at a large stage.

FILLING IN OUTDOOR POSITION AND FOR SITE DEVELOPMENT:-

Filling is done in layer of 30 cm and each layer is adequately watered.

When filling reaches the required level topmost layer is dressed to

proper section, grade and chamber and rolled by 8 to 10 tons.

Power roller and adequate watered to aid compaction.


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WATERPROOFING

INTRODUCTION: -Waterproofing is done to prevent the dampness

which is caused by rising the water from earth by the capillary action.

MATERIAL:-

a.)Elastothane

PROCEDURE:-

1.Fillet or Gola on Sharp corners:-Fillet on sharp corner: laying &placing of fillet of polymeric mortar (75 mm * 75 mm) on sharp

corner of roof with vertical wall. Make polymeric cement slurry by

adding cement to SBR(1:1 ratio) and apply by brush inside the

groove. Add fresh polymeric mortar over the groove.

Polymeric cement: Sand mortar can be prepared by adding 5-10%

SBR on gauging water and cement: coarse sand mortar (1:3)

2.Surface cracks on walls: -Surface cracks more than 2 mm shall beopen & chiseled to V groove and repaired with polymeric mortar

and extra layer of Elastothane of 6 inch shall be placed over cracks as

a crack bridging layer.

3.Basement:-Surface preparation:-


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Assure that PCC shall be smooth enough to receive primer

application.The concrete of basement must be sound enough and free

from moisture. If surface undulation is found then it shall be repaired

with polymeric cement sand mortar.

Clean properly the concrete surface and remove all dust, dirt, foreign

matters, loose particles or any deposits of contaminants, which could

affect the bond failure between the mother surface and waterproof

coating. Remove all sharp projections and make surface reasonably

smooth to receive Bituthane P a liquid applied, primer.

APPLICATION:-

Apply first coat of Elastothane over cleaned prime surface with

roller/ brush or appropriate spray application. All day work-joints,

where as the application extended more than a day use an overlap of

Elasthothane by 150 mm.

After 12-36 hours when first coat become touch dry then apply second

coat. A total composite thickness will be 1 to 1.2 mm thick and

coverage of 1 kg. to 1.20 kg per sq. m. depending upon the surface

condition. Allow the coating to cure for 24-36 hours.

SPRAY APPLICATION: Only airless spray equipment shall be used, in

case of spray application.

REPAIR OF DAMAGE LAYER OF ELASTOTHANE:-

Minor damage to Elastothanebe repaired by removing loose

membrane; cleaning the surrounding area with aromatic hydrocarbonssolvent; overlapping by 150 mm; priming the area and finishing with

two coats of Elastothane.

Elastothane is easily applied and quickly applied manually at a rate of

40 sq. m. per man per day or upto 600 sq m per man per day by spray


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application. Wipe all detail work with a cloth wet with Xylene/ Acetone

or Aromatic hydrocarbon solvent and allow drying.

The coating should be protected from damages by future operation and

other trade. Allow the coating to cure 36 hours and install protection

course after water pounding test.

Separation Layer: place 150 GSM Geotextile Mat/ 300 micron LDPE

sheet as separation layer over waterproofing coating before placing

Protection layer.

PROTECTION COURSE: - Place 50 mm thick protection screed

concrete.


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REINFORCEMENT

REINFORCEMENT GRADE: - Fe 500

BENDING OF REINFORCEMENT:-

Bars should not be heat bending.

PLACING OF REINFORCEMENT:-

All reinforcement bars shall be accurately placed in exact position

shown on the drawings,

And shall be securely tied in position during placing of concrete by

annealed binding wire not less then 1 mm in size and conforming to

Is:280, and by using stay blocks or metal chairs, spacers, metal hangers,

supporting wires or other approved devices at sufficiently close

intervals.

Bars will not be allowed to sag between supports nor displaced during

concreting or any other operation over the work.

All devices used for positioning shall be of non-corrodible material.

Pieces of broken stone or brick and wooden block shall not be used.

Layers of bars shall be separated by spacer bars, precast mortar blocks

or other approved devices.


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Chairs used to separate the two layers of slabs, walls etc. shall be

placed not more than 2 m clear in all four directions. The ratio of the

maximum horizontal length between the legs of the chair to the

diameter of bars used in preparing chairs shall not be more than100.

Spacing of cover blocks shall not exceed 1 m in any direction.

Reinforcement after being placed in position shall be maintained in a

clean condition until completely embedded in concrete.

To protect reinforcement from corrosion, concrete cover shall be

provided as indicated on the drawings.

In the case of columns & walls, vertical bars shall be kept in normal

position with timber templates having slots accurately cut in for bar

position. Such templates shall be removed after the concreting.

Dowels if provided for further lapping shall be coated with approved

quality bitumen paint over and above the anti corrosive treatment.

WELDING OF BARS:-

Welding of main bars shall not be permitted.

In special case Welding will be permitted by Client with Welding rod

7018.

Welding may be permitted for temporary works and areas where

welding will not affect the structure adversely.


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REBARING

INTRODUCTION:-

Re-baring is done where the further reconstruction is

required due to revision of Drawings after

construction.

EQUIPMENTS:-

1.Drilling machiene2.Grouting gun3.Air pump

MATERIAL:-

1.Chemical RE 500(M/S HILTI)


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CONCRETING

INTRODUCTION:-Concrete is prepared by mixing the following raw

materials in a right proportion:

1.Aggregates2. Coarse Sand or Dust3.Fly ash4.Water5.Cement6.Admixtures

Mixing of these raw materials dependson the grade of the concrete.

EQUIPMENT:-

a) For Production of Concrete:Concrete batching and mixing plant (fully automatic) with minimum

capacity of 15 cu.m. per hour.

b) For Concrete Transportation : depending upon actual

requirement

i) Concrete dumpers minimum 2 tones capacityii) Powered hoists minimum 0.5 tone capacityiii)Chutesiv)Buckets handled by cranesv) Transit truck mixervi)Concrete pumpvii)Concrete distributor booms


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viii) Belt conveyorix)Cranes with skipsx) Tremies

c) For Compaction of concrete:

i) Internal vibrators size 25 mm to 70 mmii) Form vibrators minimum 500 wattsiii)Screed vibrators full width of carriageway

(up to two lanes)

SIZE OF COARSE AGGREGATE:-

The size (maximum nominal) of coarse aggregates for concrete to

be used in various components shall be given as Table 1700-7.

ComponentsMaximum Nominal size of coarse

Aggregate

(mm)i) RCC well curbii) RCC/PCCiii)Well cap or pile cap solid type

piers and abutments

iv)RCC work in girders, slabs,wearing coat, kerb, approach

slab hollow piers and

abutments, pier / abutmentcaps, piles

v) PSC workvi)Any other item.

20

40

40

20

20

As specified by Engineer


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Maximum nominal size of aggregates shall also be restricted to

the smaller of the following values:

a)10 mm less than the minimum lateral clear distance betweenmain reinforcements

b)10 mm less than the minimum clear cover to thereinforcements.

The proportions of the various individual size of aggregates shall

be so adjusted that the grading produces densest mix and the grading

curve corresponds to the maximum nominal size adopted for the

concrete mix.

TEST FOR RAW MATERIALS:-

1.Aggregates

a)Sieve analysis of 20mm aggregateb)Sieve analysis of 10mm aggregatec) Impact test of 10mm aggregate

2. Test for the Sand

a)Sieve analysis of coarse sandb)Sieve analysis of Fine sandc)

Silt content

3.Cement

a)Sieve analysisb)Consistency test


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c)Fineness of Cementd)Initial and Final Setting Time

For Concrete:-

1.SLUMP TEST2.COMPRESSIVE SRENGTH TEST

MIXING CONCRETE:-

Concrete shall be mixed either in a concrete mixer or in a batching

and mixing plant, as per these Specifications.

Hand mixing shall not be permitted.

Mixing shall be continued till materials are uniformly distributed

and a uniform color of the entire mass is obtained and eachindividual particle of the coarse aggregate shows

complete coating of mortar containing its proportionate amount

of cement.

In no case shall mixing be done for less than 2 minutes.

Mixers which have been out of use for more than 30 minutes shallbe thoroughly cleaned

before putting in a new batch.

Mixing plant shall be thoroughly cleaned before changing from

one type of cement to another.


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TRANSPORTING, PLACING AND COMPACTION OF CONCRETE:-

The method of transporting and placing concrete shall be less

time taken.

Concrete shall be transported and placed as near as practicable

to its final position, sothat no contamination, segregation or loss

of its constituent materials takes place. \

Concrete shall not be freely dropped into place from a height

exceeding 1.5 meters.

All formwork and reinforcement contained in it shall be cleaned

and made free from standing water, dust, snow or ice

immediately before placing of concrete.

No concrete shall be placed in any part of the structure until the

approval of the Engineer has been obtained.

Except where otherwise agreed to by the Engineer, concrete shall

be deposited in

Horizontal layers to a compacted depth of not more than 450 mm

when internal Vibrators are used and not exceeding 300 mm in all

other cases.


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Concrete when deposited shall have a temperature of not less

than 5 degrees Celsius, and not more than 40 degrees Celsius.

It shall be compacted in its final position within 30 minutes of its

discharge from the Mixer,

Concrete shall be thoroughly compacted by vibration or other

means during placing and worked around the reinforcement,

tendons or duct formers, embedded fixtures and into corners of

the formwork to produce a dense homogeneous void-free mass

having the required surface finish.

When vibrators are used, vibration shall be done continuously

during the placing of each batch of concrete until the expulsion of

air has practically ceased and in a manner that does not promote

segregation.

Over vibration shall be avoided to minimize the risk of forming a

weak surface layer.

Requirements of Consistency:-

The optimum consistency for various types of structures shall beas indicated in Table . The slump of concrete shall be checked as per

IS: 516.


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TYPESLUMP (mm)

1 (a)Structures with exposed inclinedsurface requiring low slump concrete

to allow proper compaction.(b)Plain cement concrete.

25

25

2 RCC structures with widely spaced

reinforcements; e.g. solid columns,

piers, abutments, footings, well steining

40 50

3 RCC structures with fair degree of

congestion of reinforcement; e.g. pier

and abutment caps, box culverts well

curb, well cap, walls with thickness

greater than 300 mm.

50 75

4 RCC and PSC structures with highly

congested reinforcements e.g. deck slab

girders, box girders, walls with thickness

less than 300 mm

75 125

5 Underwater concreting through tremie

e.g. bottom plug, cast-in-situ piling

100 200


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1. Grade of concrete in ACC: Structure concrete M10 to M402.Grade of concrete in TBB: Structure concrete M10 to M403.Grade of concrete in ATC: Self Compacting Concrete

a)SCC M30 in Pileb)SCC M40 in Pile Cap & Above Level 9c)SCC M60 up toLevel 9

LEVELING COURSE:-It is a lean concrete mix which is placed in

position conforming line and level shown in the drawing and

compacted by approved means and cured adequately.


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INJECTION GROUTINTG

INRODUCTION: -Injection grouting is done to joint the layer of greenconcrete to the old hardened concrete.

EQUIPMENTS:

Pressure Pump Pressure Gauge Drilling/Chisel Machine Mixing Drum Pipe NRV (Non Returning Valve) Ultrasonic Pulse Velocity(UPV) Rebound Hammer Carborandum stone

MATERIALS:-

Low viscous epoxy (Conbextra EP 10) Epoxy Repair Mortar(Nitocrete) Non Shrink Cementations Grout(GP2) Nitobond/Latex

ROOT CAUSE ANALYSIS:

It is observed that during concreting of particular column due topressure of concrete minor gap has been created at corner of two

vertical shutter.


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Slurry Loss has been occurred due to improper Packing of thegaps in shuttering Material.

Inadequate tamping of the shuttering during the concreting.PROCEDURE:

The Entire Repair Procedure shall been done in 3 Stages i.eSurface PreparationEpoxy Grouting in the Honey Comb LocationNon-Shrink Cementations Grouting Surface Preparation:

a) Mark the honey combed area to be Rectified.b)Saw cut the edges with a minimum of 10mm with concrete saw

cutter.

c)Remove all loose concrete from the column until hard concretesurface with proper bonding is obtained.

d)Cleaning of all loose laitance, loose concrete up to the desireddepth by

Mechanical or manual means to have dust free surface to

have good bond

between the existing concrete and with the high strength

repair mortar.

e)Clean the Surface by water jetting.Epoxy Grouting in the Honey Comb Location

i)Drilling shall be made to a depth of 100-300mm. Just beforefixing NRV (Non Returnable Valve) packer on the cavity


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portion it shall be cleaned with the air pressure to get clean

and dry surface.

ii)Fixing of NRV packer of size 13mm for 100-300mm deep drilledholes

@ 200mm c /c in staggered manner shall be done withproper tightening to have proper packing of rubber gaskets.

iii)Injection of Low Viscous Epoxy (Conbextra EP10) in the NRVPackers with a pressure of 3-5kg/sqcm.

iv)The Injection Grouting shall last till backward pressure isobserved on further applying the pressure in the injection

grouting

v)After the injection Grouting operations are over, the nozzlesshall be removed & the area is filled with Epoxy Repair mortar.

Non-Shrink Cementations Grouting :i) The Concrete chipped surface to be grouted & filled with Epoxy

Repair Mortar.

ii)The area shall be cleaned with water / air jet to remove anyloose particles

or dust.

iii)As Recommended Latex/Nitobond shall be applied on the old &new surface either by brush or by spraying for proper bonding

with the newly laid concrete.

iv)Proper shuttering arrangement shall be taken before pouringthe Non-Shrink Cementations Grouting.

v)The Non-Shrink cementations Grout is Poured From one side &corner with proper head to fill the area & all the air voids.

vi)Allow the system to get water cured for 3 Daysvii) After the Completion of the Entire Process the Grouting

surface shall be finished with Carborandum stone


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TESTING

After completion of repair procedure, the column shall be tested byUPV and Rebound Hammer. The overall process of NDT tests (UPV

and Rebound Hammer test) results shall be satisfactory ofrepaired column structure.


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BRICKWORKMATERIAL:

1.Fly ash brick (size 230*115*75)2.

Mortar

a)Cementb)Waterc)Fine aggregate (sand)TOOLS FOR BRICK WORK:-

a.)Auto levelb.)Wooden/aluminum straight edge 3 m longc.) 3 m steel taped.) d.) Right angle m. longe.) Line and pin springf.) Plumb

g.) Storey rods

BRICK:-

a.Bricks shall be sound, hard, well burnt, uniform in size,shape&color,homogenous in texture giving a metallic ringing sound,

free from flaws,cracks,holes,lumps or grit & arises should be square,

straight and sharply defined.

b.They shall not break when struck against each other and droppedflat from a height of 1 m to the ground.

c. Maximum absorption shall not be more than 15% of its dry wt. onimmersion in water for 24 hours.

d.Min. crushing strength shall be 35 kg/sq cm.CEMENT:-Cement used shall be ordinary Portland cement conforming

to IS and shall be of grade 53 or 43.


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WATER:-water used for masonry shall be clean and free from injurious

amount of deterious materials.

SAND:- Natural sand deposited by stream or glacial agencies as a result

of disintegration of rock is the best form of fine aggregate.

The fine aggregate shall conform to following standards.

(i) For plain and reinforced concrete IS 383 specificationfor coarse and fine

Aggregates from natural source for concrete

(ii) Mortar and grout IS 2116 Specification forsand for masonry

Mortars

Sea sand should not be used.

Sand shall be hard, durable, clean and free from adherent coatings and

organic matter and shall not contain any appreciable amount of clay

Sand should not contain any harmful impurities such as iron, pyrites,

coal particles, lignite, alkali and organic impurities in such form or

quantities as to affect the strength or durability of concrete or mortar.

MORTAR:-

Mortar shall be prepared by mixing fine graded aggregate with

cement in the proportion 1:4 for 115 mm width& 1:6 for 230 mm

width & above.


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Cement and sand added to mixer shall be thoroughly mixed and

water shall be added to it gradually. After addition of water the

mixer shall run for a min. of 3 minutes.

The mortar mixed shall be consumed within 30 minutes of its

mixing.

METAL REINFORCEMENT:-

Metal reinforcement used in brick masonry shall conform to the

following IS specification.

IS 226 Specification for steel standard quality

IS 412 Specification for expanded metal steel sheet for general

purpose

IS 432 Specification for mild steel and medium tensile steel bars

IS 1566 Specification for steel fabric or hard drawn steel wire

WORKMANSHIP:-

Bricks used for masonry in cement mortar shall be soaked by

immersing in water or by hosing of water at least one hour prior

to start of actual lying.

Brick shall be laid in English bond unless otherwise specified. Half

or broken bricks shall be used only for the purpose of bond and at

no other place.

Work shall be true to horizontal lines and perfect plumb. Vertical

joint shall be truly vertical and those in alternate courses shall be

in the same vertical line. Joints of each course shall be within thelimit of 6 mm to 10 mm depending upon the size of brick.

Total ht. of 9 cm brick with 5 courses and 5 mortar joints shall be

50 cm.


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In no case joint thickness shall not increase 50 cm.

Joint should be filled to full depth and checked each time.

Required datum level must be established throughout the floor

and only then work should start.

It is equally important to take into account level of window sills,

lintels etc.

PROTECTION & CURING: - green work should be protected from rains

by suitable covering.

Masonry in cement mortar shall be kept constantly moist on all the

faces for the min. period of 10 days.

The top of the masonry shall be left flooded with water at close of the

day.


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SAFETY PRECAUTIONS:-

1.Avoid direct contact of the material with skin, eye & body.2.Wear proper safety helmets, goggles, shoes during application.3.Suitable lights for the application work during night shift should

be provided in and around the work area.

4.The area where injection grouting operations are to beundertaken must be cordoned off, and clearly signposted to

establish a restricted area.

5.All personnel to be fully attired in the required Safety gear.

Documents

Robin Report1