this report is based on pile construction of a bridge to sialkot

1. i
Training program
Author:
Salman Riaz Bsct09143041
University of Lahore Gujrat campus
Department of civil engineering and technology

2. ii
CONSTRUCTION OF BRIDGE OVER RIVER CHENAB AT
SHAHBAZPUR TO CONNECT DISTRICT GUJRAT WITH
DISTRICT SIALKOT IN DISTRICT GUJRAT
Author
Salman Riaz Bsct09143041
A Project submitted in partial fulfillment of the requirements for the degree of
B.Sc. Civil Engineering Technology

3. iii
CONSTRUCTION OF BRIDGE OVER RIVER CHENAB AT
SHAHBAZPUR TO CONNECT DISTRICT GUJRAT WITH
DISTRICT SIALKOT IN DISTRICT GUJRAT
Project Directorate
Punjab Highway Department
Government of the Punjab

4. iv
Project Team
Subcontractors:
Client Consultant Contractor
National Highway
Authority
National Engineering
Services Pakistan
National Logistic
Cell

5. v
Abstract

6. vi
Acknowledgments
We would like to thank Engr. Muhammad Waqas Zaffar for encouraging us
and for helping us to make this report complete, and The University of
Lahore Chenab Campus, Gujrat for providing us the golden opportunity of
training program so, that we could get experience about the field.
We would like to thank to Engr. Usman and National Logistics Cell (NLC)
for appointing us as internee, and providing the all the necessary information
for the completion of the report.

7. vii
Table of contents
Project Directorate....................................................................................................................................................... iii
Project Team.................................................................................................................................................................iv
Abstract..........................................................................................................................................................................v
Acknowledgments ........................................................................................................................................................vi
List of figures ...............................................................................................................................................................ix
List of tables ..................................................................................................................................................................x
Chapter 1: DETAILED ESTIMATE FOR CONSTRUCTION OF BRIDGE OVER RIVER CHENAB AT
SHAHBAZPUR TO CONNECT DISTRICT GUJRAT WITH DISTRICT SIALKOT IN DISTRICT GUJRAT.......1
1.1. HISTORY:.....................................................................................................................................................1
Chapter 2: Design and Scope ....................................................................................................................................3
2.1. Main Features: ...............................................................................................................................................3
2.2. RIVER TRAINING WORKS / GUIDE BANKS:..............................................................................................3
2.3. ROADS:..............................................................................................................................................................3
2.4. DESIGN PARAMETERS (ROADS) .................................................................................................................3
2.4.1. Main Carriageway (24’ wide)......................................................................................................................3
2.4.2. Treated shoulders (4’ wide) .........................................................................................................................3
2.4.3. MISCALLANEOUS: - ................................................................................................................................4
Chapter 3: General specifications..................................................................................................................................5
Chapter 4: Piles............................................................................................................................................................13
4.1 Type of pile:.......................................................................................................................................................13
4.2 survey: ...............................................................................................................................................................13
4.2.1 Instruments: ................................................................................................................................................13
4.2.2 Procedure:...................................................................................................................................................14
4.2.3 Obstacles during survey:.............................................................................................................................17
4.3 Boring:...............................................................................................................................................................17
4.3.1 Definition:...................................................................................................................................................17
4.3.2 Types of boring:..........................................................................................................................................17
4.3.3 Method of boring used on project:..............................................................................................................18
4.3.3.1 Why this sort of method was used? .....................................................................................................18
4.3.5: chemical during boring:.............................................................................................................................18
4.3.5.1 Why bentonite?....................................................................................................................................18
4.3.6 procedure:...................................................................................................................................................19
4.3.7 Explanation:................................................................................................................................................20
4.4 Mild steel sheet installation: ..............................................................................................................................21
4.4.1 Dimensions of Mild steel sheet:..................................................................................................................21
4.4.2 purpose: ......................................................................................................................................................21
4.5 steel cage preparation and checking: .................................................................................................................22
4.6 cage lowering:....................................................................................................................................................23

8. viii
4.6.1 Iron rod:......................................................................................................................................................24
4.6.2 wooden wedges:..........................................................................................................................................24
4.6.3 lowering of upcoming cage: .......................................................................................................................25
4.6.4 welding: ......................................................................................................................................................26
4.6.5 lapping:.......................................................................................................................................................26
4.6.6 spacer:.........................................................................................................................................................27
4.7 pouring/concreting:............................................................................................................................................27
4.7.1 Type of cement used:..................................................................................................................................27
4.7.1.1 Why Hydraulic cement? ..........................................................................................................................28
4.7.1.2 Ratio: .......................................................................................................................................................28
4.7.1.3 Sand:........................................................................................................................................................28
4.7.1.4 Crush:.......................................................................................................................................................28
4.7.2 Method:.......................................................................................................................................................30
4.7.2.1 Explanation:.........................................................................................................................................30
4.7.2.2 Note: ................................................................................................................................................30
4.6.2.3 Procedure:..........................................................................................................................................30
4.7.2.4 Note: ....................................................................................................................................................31
4.7.3 Obstacles during concreting: ......................................................................................................................33
4.7.3.1 How problem was encountered:...........................................................................................................33
4.7.3.2 Reason of temperature control:............................................................................................................34
4.7 Sounding:...........................................................................................................................................................35
4.7.1 Definition:...................................................................................................................................................35
4.7.2 Explanation:................................................................................................................................................35
4.8 Removal of stand pipe: ......................................................................................................................................35
4.9 Surveying:..........................................................................................................................................................35
4.10 Concrete cutting:..............................................................................................................................................36

9. ix
List of figures
Figure 1 Instruments used for survey. .........................................................................................................................14
Figure 2 Sequential activity of stand pipe installation.................................................................................................16
Figure 3 Bentonite resisting side walls of pile borehole..............................................................................................19
Figure 4 water reservoir used for boring .....................................................................................................................20
Figure 5 machine used for boring................................................................................................................................20
Figure 6 Mild steel sheet .............................................................................................................................................21
Figure 7 Steel cage lowering sequence........................................................................................................................23
Figure 8 Iron rods passed through the cage .................................................................................................................24
Figure 9 wooden wedges in the dowels.......................................................................................................................25
Figure 10 lowering of upcoming cage .........................................................................................................................25
Figure 11 welding of cages..........................................................................................................................................26
Figure 12 cage splicing................................................................................................................................................27
Figure 13 Spacer..........................................................................................................................................................27
Figure 14 Pile concreting by tremie method................................................................................................................30
Figure 15 Sequential activity of tremie preparation.....................................................................................................32
Figure 16 Gunny bag wrapped around transit mixer drum..........................................................................................33
Figure 17 Ice blocks in water to be used for concrete preparation ..............................................................................34
Figure 18 Water showering on transit mixer drum......................................................................................................34
Figure 19 Removing stand pipe...................................................................................................................................35
Figure 20 determining center point of a poured pile....................................................................................................36
Figure 21 concrete cut .................................................................................................................................................37
Figure 22 Main phases of pile completion...................................................................................................................37

10. x
List of tables
Table 1Mix design of pile concrete .............................................................................................................................29

11. 1
Chapter 1: DETAILED ESTIMATE FOR
CONSTRUCTION OF BRIDGE OVER RIVER CHENAB
AT SHAHBAZPUR TO CONNECT DISTRICT GUJRAT
WITH DISTRICT SIALKOT IN DISTRICT GUJRAT
1.1.HISTORY:
The scheme is included in the current year ADP 2016-17 at G.S No. 2816 with an allocation
of Rs. 350million.
The administrative approval of the scheme has been issued by the secretary to the
government of the Punjab, communication &work departments, Lahore vide letter
No.SO-11(C&W)3-11/2015(Vol-1) dated 11.11.2016 for Rs. 3917.701 M
District Gujrat is an important district of Punjab and is known internationally due to its
cottage industry like fans, Furniture and pottery. Most of the people of Gujrat are residing
overseas. The is not having any air connection with international airways and inhabitants
have to travel long distances either to reach Lahore or Islamabad. An international airport
at Sialkot is closely located to Gujrat. However, there is a natural constraint of river Chenab
to access this airport. It is pertinent to mention here that a dry port is also located in district
Sialkot & it will be the shortest possible route between two major districts of Punjab.
The proposed bridge is located on river Chenab at village Shahbazpur, which is 10.5Kms
away from Jalalpur Jattan in district Gujrat. On the right bank of river Chenab district
Gujrat falls while on the left bank boundary of district Sialkot starts.
The people on either side of river Chenab has to travel a long distance via Head Marala or
via Wazirabad for their trading goods. As a result, the people putting up in the area has to
face a lot of inconvenience and disaster to achieve their goals. It is a long-standing demand
of the public to have a bridge over river Chenab near Shahbazpur.

12. 2
More over from defiance point of view this is to be the shortest route for the abrupt
communication of army authorities from Kharian cantt to Sialkot Cantonment area, as it is
a fact that a net distance of 18 Kms will be reduced from Kharian to Sialkot via shahbazpur
as compared to the travelling distance via Wazirabad.
The construction of bridge along with protection work / guide banks will decrease the
occurrence of flood in future, as the guide banks will train the flood through this bridge
and population at large will be benefited.
The single carriageway bridge has been adopted having 28’ clear roadway 5’ footpath on
both sides. In addition to these approaches, guide banks, connecting roads &toll plaza,
Marginal Bund, Spurs etc. have also been incorporated in the estimate. The bridge on its
completion would also serve to be a regular source of income for the provincial
government, as a Toll plaza will also be constructed for collecting Toll tax from the
vehicles availing the facility of this bridge.
PC-1/ Cost Estimate amounting to Rs. 5103.158M prepared on the basis of rates of 1st
Half
2016 was submitted to planning & development Department, Lahore against printed cost
of Rs. 2070M by secretary to Government of the Punjab, Communication & Works
Departments, Lahore on 21.04.2015.
In the light of approved estimate, this Detailed Estimate announcing to Rs.4070.218M has
been framed for arranging Technical Sanction.

13. 3
Chapter 2: Design and Scope
2.1. Main Features:
Length of Bridge = 3426R ft.
Width of Bridge = 28’ clear 5’ footpath on
both sides
2.2. RIVER TRAINING WORKS / GUIDE BANKS:
Up-Steam side = 3782R ft.
Down-Stream side = 500R ft.
2.3. ROADS:
Connecting Roads
Gujrat side =10.50Kms
Sialkot side = 8.35Kms
2.4. DESIGN PARAMETERS (ROADS)
2.4.1. Main Carriageway (24’ wide)
Sub base course = 10” thick
Base course of crushed stone aggregate = 10” thick
Surfacing = 4” bituminous carpet in
Two layers
2.4.2. Treated shoulders (4’ wide)
Sub base course = 6” thick
Base course of crushed stone aggregate = 6” thick

14. 4
Surfacing = TST (Light)
2.4.3. MISCALLANEOUS: -
Marginal Bund (Irrigation Dept.)
Spurs (Irrigation Dept.)
Toll Plaza

15. 5
Chapter 3: General specifications
1. The bridge has been designed on the basis of field data supplied by the executive engineer
provincial highway division Gujrat.
2. All drawings shall be read carefully before the execution of the work. In any case of
discrepancy or omission this office shall be consulted.
3. All reduced levels given on drawings are in feet and refer to the survey/bench marks.
4. Except otherwise noted concrete shall be designed mix using ordinary Portland cement as
per BS standards and having minimum 28 days strength on 6 inches cubes as specified
below:
a. Prestressed members……………………………………………………6000 PSI
b. All other reinforced members…………………………………………...3750 PSI
c. Piles (10% extra cement over and
Above the normal requirement for the
Design mix shall be added) …………………………………………….3750 PSI
5. Lean concrete shall be 1:4:8 nominal mix.
6. Conventional reinforced steel shall be deformed round bars conforming to ASTM A 615
having 60000 PSI minimum yield strength.
7. Lap splicing of main bars in piles/columns shall not be allowed at locations other than the
as shown on drawings. Except otherwise shown on drawings all laps of reinforcing bars
shall be staggered and lap splicing of more than 50% bars within the lap length zone shall
not be allowed, and minimum lap length shall be as under:

16. 6
Bar size #3 #4 #5 #6 #8 #9 #10 #11
Top bar lap length 1’-5” 1’-10” 2’-4” 3’-0” 5’-3” 6’-8” 8’-6” 10’-6”
Bottom bar lap
length
1’-0” 1’-4” 1’-8” 2’-1” 3’-9” 4’-9” 6’-0” 7’-6”
*Top bar = the having 12 inches or more concrete beneath the bar
8. Except otherwise shown on drawings bars terminating in hook shall conform to the
following:
9. Prestressing steel must be uncoated seven- wire stress relieved strands of 0.5-inch nominal
size having minimum ultimate strength of 270 KSI conforming to ASTM A-416.
10. Multi strand system of prestressing to be used.
11. Galvanized fully corrugated steel sheathing having strip thickness not less than 0.30mm
shall be used. The water tightness between sections of sheaths shall be ensured by
appropriate means to the satisfaction of the engineer in charge.
12. The anchorages to be used for post tensioning tendons shall be conformed to AASHTO
standard specifications for highway bridges and further to post-tensioning institute (PTI)
USA “acceptance standards for post-tensioning systems”.

17. 7
13. Live anchorages shall be used at both ends of tendons in case of one end stressing of deck
slab and diaphragms, and use of dead anchorages shall not be allowed.
14. The strength of concrete at transfer of prestress force shall not be less than the strength
specified at 4 (a) above.
15. Prestressing tendons shall be stressed simultaneously at both ends of pre-cast beam, but
the diaphragm and the deck slab, tendons shall be stressed at one (alternate) end only.
16. Diaphragm tendons and deck slab tendons shall be stressed before casting footpath, railing
and laying carpet. The top swept tendons of precast beam shall be stressed after stressing
the diaphragm and deck slab tendons but before casting footpath, railing and laying carpet.
17. The specified extensions on drawings have been worked out using modulus of elasticity of
steel “E” as 28.5 x 106
, coefficient of curvature friction “µ” as 0.25 and coefficient of
wobble friction “K” as 0.0010/FT. pull-in/anchorage loss has not been included in the
specified values of extensions.
18. The extensions and jack pressures shall be re-evaluated before starting stressing of tendons,
on the basis of “E” value of steel obtained as per steel test results, value of “K” if different
from the above specified value, pull-in/anchorage loss effective tendon length, prestressing
system/hardware and shall be submitted to the engineer in charge along with the relevant
jack pressures for obtaining approval.
19. If the observed pull-in loss in tendon at each anchorage exceeds ¼ inch the tendon shall be
de-stressed by approved means and shall be re-stressed by using new grips.
20. If the actual extension observed varies more than 3% of the evaluated values against the
relevant evaluated jack pressure, tendon shall not be locked and further instructions shall
be obtained from the engineer in charge.

18. 8
21. Intermediate grout vents shall be provided for all tendons of precast beam at about mid
span.
22. All tendon ducts shall be grouted after stressing with neat port land cement grout using
water cement ratio of 0.50.
23. Appropriate pressure grouting method shall be adopted to ensure grouting in full length of
ducts.
24. Grout shall be passed through a screen with 1/6-inch maximum clear opening prior to being
introduced to the grout pump.
25. After stressing, trimming, and grouting operations all anchorage pockets shall be filled with
1:1:2 concrete using 3/8-inch down aggregate.
26. All appropriate measures shall be adopted during the prestressed beams and stability of
beams shall be ensured until lateral support by diaphragms.
27. Boring of piles shall be done by appropriate method and stability of soil in the bore shall
be ensured by all means.
28. Soil samples shall be obtained from different levels during boring of piles and shall be
compared with subsoil investigation report by the engineer in charge and in case of any
discrepancy this office shall be consulted.
29. Concreting in piles shall be done only by tremie method only.
30. Piles shall be concreted minimum 6 FT. above the finish level which shall be cut off later.
31. Earth side faces of abutment walls shall be coated with hot bitumen applied at the rate of
15LBS/100 SQ. FT.
32. Except otherwise noted on drawings cover to outer bars shall be 1 ".
33. Except otherwise shown all arises shall be chamfered 1” x 1”.

19. 9
34. Laminated neoprene rubber bearing pads shall be of 60 hardness (shore a durometer) and
shall conformed to the AASHTO bridge construction specification.
35. The steel / alloy expansion joints may be imported, European made or equivalent having
capacity to accommodate 50 mm deformations and as approved by the engineer in charge.
36. Written and evaluated dimensions shall be overwhelming the scale measurements on
drawings.
37. All work piles are suggested to be tested by any appropriate method to ensure their integrity
and correctness before casting pile caps.
38. Accelerating admixtures are not to be used.
39. All necessary measures shall be adopted by the contractor in order to minimize hydration
temperature of concrete.
40. Abbreviations and symbols: -
i. ABUT. = abutment
ii. B =bottom
iii. B.B. =burnt bricks.
iv. B.L. = bed level
v. B.M. = bench mark
vi. C/C = center to center
vii. C.JNT. = construction joint
viii. C.L. = center line
ix. Conc. = concrete
x. C/S = cement sand mortar
xi. DIA = diameter

20. 10
xii. DIAPH. = diaphragm
xiii. DRG = drawing
xiv. D/S = down stream
xv. E.F. = each face
xvi. E.JNT. = expansion joint
xvii. H = horizontal
xviii. H.F.L. = high flood level
xix. I.F. = inner face (earth side)
xx. L.G.B = left guide bank
xxi. MAX. = maximum
xxii. MIN. = minimum
xxiii. N.S.L. = natural surface level
xxiv. N.T.S. = not to scale
xxv. O.F. = outer face
xxvi. P = pier
xxvii. R = radius of curve
xxviii. R.G.B. = right guide bank
xxix. S = slope
xxx. T = top
xxxi. U/S = up stream
xxxii. T&B = top and bottom
xxxiii. V = vertical
xxxiv. = : equal

21. 11
xxxv. : dia
xxxvi. : symmetric about center line

22. 12
No. Members Quantity
1 Abutment piles 4
2 Piers piles 42
3 Spans 22
4 Pre-stressed beams 88
5 Pier caps 21
6 Bearing pads 176
Members of Bridge

23. 13
Chapter 4: Piles
4.1 Type of pile:
The piles were end bearing piles.
4.2 survey:
First of all, the co-ordinates were marked with the help of survey, where the piles were supposed
to be drilled. Surveyor prepares the site for execution.
4.2.1 Instruments:
The instruments used in survey were as follows:
i. Total station.
ii. Prism.
iii. Auto level.
iv. Staff.

24. 14
Figure 1 Instruments used for survey.
4.2.2 Procedure:
i. Coordinates where total station should be place were given.
ii. Coordinates where piles were supposed to be bored were stored in the total station.
iii. By the help of total station, the coordinates were found where the piles were supposed to
be drilled. As total station telescope moved towards the coordinate of boring, the coordinate
on the total station screen came near to zero, which meant that coordinate is about come.
iv. By keeping the coordinates as centre point, the pit of 7’x7’ was excavated around the center
point to make bed for stand pipe.
v. After excavation of pit, the stand pipe of 6’- 6” was installed in the pit.
vi. By the help of auto level, readings from four sides of stand pipe were taken, and it was
made sure, that the stand pipe was on the level or not.
vii. If stand pipe was not on the level, it was adjusted by the help of excavator.
viii. If the stand pipe was on level, then the wooden plank was placed on the stand pipe to again
make sure whether the coordinate is still the centre point or not.
ix. The point where coordinate matched on plank was marked.

25. 15
x. By the help of steel tape was checked, that the distance on both sides from the point marked
on the plank is equal.
xi. If the distance was equal, then the stone was dropped from right below the point marked
on the plank.
xii. Then prism was placed on the point where the stone was dropped to check the coordinate.
xiii. It was made sure that the center point of pit and plank placed on the stand pipe were same.
xiv. After ensuring the both coordinates and levels of stand pipe, boring was permitted to be
commenced.
Another method to check the accuracy of stand pipe was, four points were fixed around the
stand pipe from the centre point of stand pipe. The distance between each fixed point and
boundary of standpipe right before the fixed point was measured by the help of measuring tape.
It the distance is same it means stand pipe is on the required point. This method tells that from
which point standpipe is tilted or is supposed to be set.

26. 16
Figure 2 Sequential activity of stand pipe installation.

27. 17
4.2.3 why total station and auto level were used?
Auto level:
Auto level was used, owing to auto level it is easy to verify that points are on the same plane or
not e.g. it was verified by the help of auto level that stand pipe is on the same level or not.
Total station:
Total station was used, owing to total station it was easy to determine the exact location where the
piles were supposed to be constructed.
4.2.4 Obstacles during survey:
Owing to high temperature it was very difficult to take reading in day time because of high sun
radiation. Owing to this reason the total station was shifted on a new point, and the previous point
was used as back site.
4.3 Boring:
4.3.1 Definition:
The process of drilling a hole, tunnel, or well in the earth.
4.3.2 Types of boring:
i. Displacement boring.
ii. Wash boring.
iii. Auger boring.
iv. Rotary drilling.
v. Percussion drilling.
vi. Continuous sampling

28. 18
4.3.3 Method of boring used on project:
The piles were bored by reverse boring or wet boring method.
4.3.3.1 Why this sort of method was used?
This sort of boring method was used owing to the resistance of strata.
4.3.5: chemical during boring:
Bentonite was used during the boring.
During boring for pile, the side of the bore hole is subjected to various types of forces & pressure
like active earth pressure, overburden pressure, hydrostatic pressure, pore pressure due to
underground water, etc. due to which the side of bore becomes unstable and start collapsing if
the soil strata is weak.
When bentonite is added with water in the bore hole, due to chemical action with water it forms
a layer which gets stick with the walls of the bore hole.
4.3.5.1 Why bentonite?
The reasons of using bentonite were:
i. The soil strata were weak, and the bore hole could get collapse, that’s why bentonite was
used, because of its low permeability and its thixotropic (getting viscous) property which
prevents the soil form falling into the bore hole.
ii. Bentonite reduces the chances of groundwater pollution due to boring.

29. 19
Figure 3 Bentonite resisting side walls of pile borehole
4.3.6 procedure:
i. Reservoir was made to store the water.
ii. The reservoir was connected to the stand pipe.
iii. The water was poured into the reservoir by the help of powerful pumps.
iv. After stand pipe got filled with water, bentonite was added.
v. Boring was started.
vi. After achieving the required depth of pile bore, bore was checked by sounding method
(as given in heading no. 4.7).
vii. After ensuring the depth, the bore was recommended for cage lowering.
Bentonite
slurry

30. 20
Figure 4 water reservoir used for boring
Figure 5 machine used for boring
4.3.7 Explanation:
When the water comes in contact with soil, it softens the soil which makes the drilling process
easier. The viscous water in the borehole dissolving soil in it is sucked by the pump which is
discharged in to the reservoir. As the soil particles get confined so they settle down in the bottom
of the reservoir and the water again goes in to borehole through standpipe inlet. In this way, the
borehole gets deeper. Meanwhile this process is going on, bentonite gets stick to the borehole wall

31. 21
and forms a thin layer on it which resists the borehole wall soil from falling in to the borehole.
Bentonite is used as a drilling fluid.
4.4 Mild steel sheet installation:
After when the boring process was completed, the galvanized steel sheet was installed before cage
lowering.
4.4.1 Dimensions of Mild steel sheet:
Height = 20FT
Internal diameter = 6’6”
Thickness = 8mm.
4.4.2 purpose:
The purpose of installing this sheet is to prevent the concrete of piles from scouring. The reason
of using mild steel is, mild steel is resistant to oxidation.
Figure 6 Mild steel sheet

32. 22
4.5 steel cage preparation and checking:
Meanwhile boring process was going on, on the other hand in steel yard cages were getting
prepared. After when cage welding got completed, the steel cage was checked by the in charge in
steel yard, whether all the bar bending schedule elements are present in the steel cage in required
quantity or not. After ensuring that cage is up to the mark, the cage was recommended to be loaded
on transportation mean.
Figure 7 sequential activity of cage preparation and loading

33. 23
4.6 cage lowering:
After the installation of mild steel sheet, cage lowering process was started. Owing to long length
of piles, the cage of actual length cannot be placed at once, so that’s why the steel cage was divided
into cages, we made the placement of steel cage easier.
Figure 8 Steel cage lowering sequence

34. 24
4.6.1 Iron rod:
After installing single cage, the iron rods were passed through the cage. The purpose of passing
iron rods through the cage was to prevent the cage from falling down into the bore.
Figure 9 Iron rods passed through the cage
4.6.2 wooden wedges:
Wooden wedges were used to make space between the dowels of cage lowered. This could make
easier to link the bottom bars of upcoming cage with the dowels of the cage lowered.

35. 25
Figure 10 wooden wedges in the dowels
4.6.3 lowering of upcoming cage:
After the space is made by wooden wedges, dowels of previous cage are crossed with bottom bars
of upcoming cage. The direction of cage was handled by the help of rope.
Figure 11 lowering of upcoming cage

36. 26
4.6.4 welding:
Before lowering of another cage, previous cage dowels were welded (by electric welding
process) with upcoming cage bottom bars to make the bond strong between both cages.
A single steel is of a great length, and it is difficult to place such a massive steel cage at once.
That’s why the steel cage is divided in to number of cages, all cages are welded with each other
to join them together, so they can act as a single member. Division of cage makes the placement
of pile steel cage easier.
Figure 12 welding of cages
4.6.5 lapping:
After welding, the welded area is overlapped with #4 steel bar of length of 1’-10” (as given in
chapter3, specification no. 7) to splice the cages.

37. 27
Figure 13 cage splicing
4.6.6 spacer:
Spacer is round molded shape made of concrete with a hole in it, so that reinforcement can b pass
through it. It used in cages so that the concrete can easily flow around the rebars and to keep the
pile in center of the bore. The radius of the spacer was 3”.
Figure 14 Spacer
4.7 pouring/concreting:
4.7.1 Type of cement used:
Hydraulic cement was used in preparation of concrete (as given in chapter no.3, specification no.
4).

38. 28
4.7.1.1 Why Hydraulic cement?
In piles, hydraulic cement was used because it is property of hydraulic cement that after getting
hard it resists water. Pile could get damage if ground water gets enter in it. Another reason of
using this sort of cement is, piles once get damaged cannot be repaired owing to its depth, so it is
better to take precautions at initial stage.
4.7.1.2 Ratio:
The ratio used in pile concrete was 1:2:4 with 10% extra cement (as given in chapter no.3,
specification no.4 c).
4.7.1.3 Sand:
The used in the concrete was of Sargodha. River Chenab sand was not used owing to its high
moisture content.
4.7.1.4 Crush:
Crush used in concrete was of Sargodha, because in Pakistan, Sargodha crush is known as best
crush, owing to its high strength.

39. 29
Contractor: NLC Engineering
Consultant: NESPAK
Concrete Mix Design for Pile of 1(m³)
Sr. No. Material Description Crush Size
Weight
(Kg) Percentage Remarks
1 Crush
a 20-25 mm 553 50%
b 10-20 mm 443 40%
c 5-10 mm 110 10%
2 Cement 442
3 Water 228
4 Sand 518
Table 1Mix design of pile concrete

40. 30
4.7.2 Method:
Pouring of piles was done by tremie (as given in chapter no. 3, specification no. 29).
4.7.2.1 Explanation:
The tremie concrete placement method uses a vertical or near vertical pipe with a hooper on the
top of it, through which concrete is placed by gravity feed below water level. This method is used
to place concrete in underwater foundations or in offshore concreting. cement loses its strength and
fade away under water, so this method is to be used.
Figure 15 Pile concreting by tremie method
4.7.2.2 Note:
Pouring without tremie method can cause segregation of aggregates or imperfections around the
reinforcement.
4.6.2.3 Procedure:
i. The pipe closed with a plug or thick polythene sheet or other suitable material to prevent
the water in bore hole from entering in the funnel (to prevent the water in bore hole from
entering in the pipe) was inserted in the bore hole, and was locked by the locker to prevent
falling of pipe in the bore hole. And second pipe was joined with it, in this way pipes were
joined together to achieve the required length of tremie.

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ii. The funnel was installed on the top of the tremie pipe.
iii. A plug in the funnel was installed, so that the concrete could flow with pressure into the
tremie pipe.
iv. Funnel was filled with concrete by the help of transit mixture.
v. Plug was pulled out from the funnel by mechanical mean and concrete started flowing in
the tremie pipe.
vi. A jerk was provided to the tremie. Due to application of jerk and weight of the concrete
inside the pipe, the bottom plug fell and the concrete got discharged.
vii. In this way, the water in the bore hole got displaced by the concrete.
viii. Meanwhile concrete is poured, the rising level of concrete is checked by sound method (as
given in heading no. 4.7).
ix. As the concrete level in the bore hole rises, one by one, tremie pipe is unscrewed.
4.7.2.4 Note:
i. During the concreting, air and water must be exclude from the tremie by keeping the pipe
full of concrete all the time; and for this reason, the capacity of the hopper should be at
least equal to that of the tremie pipe.
ii. Threads of each tremie pipe should be greased properly, so that it could be easy to unscrew
right after pouring.
iii. Tremie pipe must be cleaned right after the pouring is completed.
iv. Make sure that the end of the tremie pipe remains inside the concrete, because this will
prevent entering of water into the pipe from the bottom.
v. Pumping of water should not be allowed while concreting, because it may suck cement
particles from the concrete.

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vi. No compaction is required for under water concreting, as concrete gets compacted by the
hydrostatic pressure of water.
Figure 16 Sequential activity of tremie preparation

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4.7.3 Obstacles during concreting:
The contractor should take each and every possible step to reduce the heat of hydration (as given
in chapter no. 3, specification no. 39). The main problem was to reduce the hydration temperature
of concrete because the minimum temperature of site was varying between 35°C-44°C and above.
4.7.3.1 How problem was encountered:
The temperature of site was high at day time. The main aim was to create a cool environment for
concrete that’s why three possible steps were taken to reduce the hydration temperature of
concrete:
i. Pouring activity was shifted to night.
ii. In day time, ice blocks were used to cool the temperature of water which was used in
concrete.
iii. Gunny bags were wrapped around the transit mixer drum, and continuously water was
showered on it to control the temperature of the concrete.
Figure 17 Gunny bag wrapped around transit mixer drum

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Figure 18 Ice blocks in water to be used for concrete preparation
Figure 19 Water showering on transit mixer drum
4.7.3.2 Reason of temperature control:
The reason of reducing the heat of hydration was to prevent the concrete from shrinkage cracks, if
the concrete cracks, then the pile would not be able to bear the load of the superstructure.

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4.7 Sounding:
4.7.1 Definition:
The process of determining depth of bore holes.
4.7.2 Explanation:
A spacer was tied by the help of rope and then dropped into the bore hole. The point where the
spacer stopped going down further, was then measured by measuring tape, measurement of wetted
rope was the depth of borehole.
This process was done during boring to determine the depth of borehole, whether the required
depth was achieved or not, and during the pouring to determine, up to what level concrete was
poured.
4.8 Removal of stand pipe:
Right after 24 hours of pouring, the stand pipe was removed.
Figure 20 Removing stand pipe
4.9 Surveying:
After pouring was completed, the concrete got hardened and survey was done to check the center
point of pile, by the help of total station whether the center point of pile is matching to the given

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co-ordinate or not. This final survey was done by consultant, if pile is not on the required
coordinate, then consultant claims.
Figure 21 determining center point of a poured pile
4.10 Concrete cutting:
After the removal of stand pipe, concrete up to 6ft. was cut by mechanical means, because concrete
was poured 6ft. above the finish level (as given in chapter no. 3, specification no. 30). Above the
finish level the column cage was supposed to be tied.
As 24 hours passes after pouring, stand pipe is removed. The concrete above finish level is not
much hard, and is easy to be cut in a good manner.

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Figure 22 concrete cut
Figure 23 Main phases of pile completion

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