Page 1 of 22

CONSTRUCTION OF HYBRID PILE FOUNDATIONS: A CASE STUDY

OF HYBRID PILE FOUNDATION P3 OF BRIDGE NO. 43 AT BAKKAL

OF USBRL PROJECT

Author: Praveen Kumar, IRSE 2009, Senior Safety Officer/Engg., Safety Organisation, Northern Railway

Abstract

This paper describes and analyses the execution aspects of construction of hybrid pile

foundations. To study, understand and analyze the execution aspects, the hybrid pile foundation

P3 of Bridge No. 43 of USBRL project is considered. Bridge No. 43 has hybrid pile foundations

from Abutment A1 to Pier P3. The geology at the site of construction of hybrid pile foundation

P3 is studied along with the recommendations. Thereafter the methodology adopted for

excavation and slope protection works to reach the ground level for drilling and concreting of

piles of hybrid pile foundation P3, is studied. The staking of the survey coordinates of 155 piles

(98 outer and 55 inner piles), drilling of bore holes, lowering of reinforcement cage and

concreting of these piles is discussed. The construction of top ring beam, excavation to the

bottom of bottom pile cap, reinforcement binding of bottom pile cap, concreting of bottom pile

cap, construction of bottom ring beam, plain cement concrete(PCC) infilling and construction of

top raft is then described. The quality of concrete used in construction of hybrid pile foundation

P3 is studied using materials testing, concrete production at the batching plant, 28-days concrete

cube strength test results and permeability test of concrete.

1. INTRODUCTION

This paper describes and analyses the

execution aspects of construction of hybrid

pile foundations. To study, understand and

analyze the execution aspects, the hybrid

pile foundation P3 of Bridge No. 43 of

USBRL project is considered. Bridge No. 43

is continuous composite welded plate Girder

Bridge of length 777m. Bridge no. 43 has 12

piers-P1 to P12 and abutments A1 and A2

with 13 spans of 35m, 53m, 10x64m, 49m

and being constructed under Scheduled

Contract Agreement for construction of 16

Bridges. It has hybrid pile foundations from

Abutment A1 to Pier P3. The chainage of

the center line of hybrid pile foundation P3

is Km 49/629.713 and the founding level of

top raft is 840 m. The height of pier and pier

cap over the hybrid pile foundation P3 are

5.793 m and 1.5 m respectively. The

spherical bearing which permits movements

in the longitudinal direction is to be

provided on substructure over hybrid pile

foundation P3. Table 1 and Table 2 provides

the details of hybrid pile foundation P3.

Figures 1 to 4 provides the construction

details of the hybrid pile foundation P3.

2. GEOLOGICAL INVESTIGATION

The scope of geological investigation works

in connection with construction of

foundations (from A1 to P3) included

mainly drilling NX size exploratory

boreholes at different locations of Abutment

A1 and Piers P1, P2 and P3 on pier locations

as well as on both sides of centre

Page 2 of 22

line/alignment on the up slope and down

slope area. The exploratory drilling was

done from 35 m to 60 m depth below ground

surface at each location with triple tube core

barrel for achieving maximum core

recovery. After analysis of borehole data,

field observations as well as lab test data,

final geotechnical investigation report was

prepared along with necessary

recommendations regarding slope stability at

A1, P1, P2 and P3 locations. At Bridge site

16 number of bore holes were drilled

between chainage Km 49/477.713 to Km

49/629.713 on center line and either sides of

the center line at an offset of 20 m and 40 m

in the down slope and at 20 m offset in the

up slope area. Picture 1 shows geological L

section along hybrid pile foundations A1 to

P3. Picture 2 shows geological cross section

at hybrid pile foundation P3.

The report indicated that at Pier- P3, the bed

rock encountered at deeper depth of 37.20m

below ground surface at P3D2 location, at

58.00m below existing ground level at P3D1

location and bed rock not met up to explored

depth of 50.00m & 55.00m at P3CL & P3U1

locations respectively indicating thick cover

of slope debris material all along the slope.

The slope was quite steep in the middle part

due to presence of small exposures of

brecciated material also exposed along the

slope at places which was quite hard &

compact in nature but extended up to

shallow depth only (as per bore hole data).

The cutting of the slope was required to be

done in slope debris material and brecciated

material only at suitable angle with the

provision of berms in between two

consecutive slopes and required support

measures in the form of shotcreting, wire

mesh & rock bolting. The report

recommended to design the deep well / pile

foundation at this pier location and rested on

bed rock at deeper depth.

Further, the report recommended that the

cutting of slope should be done in proper

way by cutting of slope in a proper angle &

height and providing berms of suitable width

in between two consecutive slopes. The

overburden should be removed during

cutting of slope where bedrock is at shallow

depth and overhangs should be removed to

avoid any incident in the future.

Based on the geological, geotechnical

investigation reports and site visits to the

location of Bridge No. 43, the designer

RITES India and RAMBOLL Consultants of

Denmark designed the hybrid pile

foundations for abutment A1 and piers P1 to

P3. The proof checking of the design was

done by Anwikar Consultants, Germany.

3. EXCAVATION

The location where the hybrid pile

foundation P3 was to be constructed was not

directly available as it was overlain by soil

and rock. Therefore excavation had to be

done and access roads had to be created so

as to enable the manpower, machinery and

materials to provide the slope protection

measures and reach the sites of construction

of the hybrid pile foundation P3. The sites

were cleared of all the obstructions to enable

the setting out for excavation. Thereafter

survey points were marked on the ground

for excavation by considering the excavation

margin for subsequent works involved in the

construction of hybrid pile foundation P3.

The excavation had to be done in slopes and

berms as per the approved drawing. Figure 5

Page 3 of 22

and 6 shows the details of slopes and berms

which had to be achieved by the excavation.

For carrying out the protection works, berms

were created in the existing strata on which

the shotcrete spraying machine and Atlas

Copco ROC machine was used for

shotcreting and rock bolting of slopes

respectively. The excavators and/or

breakers were used for excavation in soils

and rocks and thereafter dumpers were used

to transport the excavated muck to the

designated dumping sites. Picture 3 shows

excavation in progress at the location of

hybrid pile foundation P3.

The steel fibre reinforced shotcrete of 100

mm thickness with fibre content of 40

kg/cum was provided on slopes in two

layers of 50 mm each, with the

reinforcement wire mesh of 100 mm x 100

mm x 3.15 mm dia conforming to IS:1566

with nominal mass of 1.25 kg/sq.m, in

between the two layers by wet shotcreting

method. The grade of Shotcrete was M25

and was to be applied on slopes as per

IS:9012:1997.

The rock bolts of 11 m length were provided

in the slopes with the Atlas Copco ROC

machine. The rock bolts were 32 mm in

diameter and of grade Fe500D. The rock

bolts were installed in 100 mm diameter

drilled holes and grouted with 30 MPa

cement grout. The orientation of the rock

bolts were decided by the geologist

considering the site conditions. The spacing

between the rock bolts was 1.5 m c/c

horizontally and vertically in the staggered

pattern. The protective coating of cement

inhibitor solution was applied on rock bolts

and bearing plate. The rock bolts were

tightened using torque wrench to generate an

axial tension equivalent to 25 percent of

design capacity of rock bolt (For 11 m long

rock bolts it comes out to be 5.75 tonnes).

One percent of working rock bolts of 11 m

lengths were to be tested up to 10 percent

more than the safe working load of 2

tonnes/m.

The weep holes were provided on slopes

@2.5 m c/c in both directions. Wherever the

distance of rock bolt was less, the weep

holes were located at the center of 4 rock

bolts.

The excavation was done at the location of

hybrid pile foundation P3 up to the ground

level just above the level where the

embedded reinforcement of piles had to

terminate in the top raft (i.e. 1.5 m above the

bottom of the top raft).

The total steel fibre reinforced shotcrete

provided was 1261 sq.m and total number of

rock bolts provided were 416.

Table 10 provides the details of number of

days taken to complete the excavation,

shotcreting and rock bolting for hybrid pile

foundation P3.

4. SURVEY AND LAYOUT MARKINGS

FOR PILES

The control pillars were established at the

site of hybrid pile foundation P3 after

excavation was completed to reach the

ground level just above the level where the

embedded reinforcement of piles had to

terminate in the top raft i.e around RL 841.5

m. Picture 4 shows the ground level reached

for starting drilling of piles of hybrid pile

foundation P3. The top level of the outer

piles was higher than that of the inner piles

but the founding level of all the piles was

same. The pile drilling for all the 153 piles

Page 4 of 22

was done from the same ground level. This

innovative working for drilling of piles

avoided the space constraints which would

have been encountered by the drilling rig

had the drilling of outer and inner piles been

done at different levels. The northing and

easting coordinates of the 153 piles were

determined in AUTOCAD software. Table 9

shows the survey coordinates of the 153

piles of the hybrid pile foundation P3.

Figure 7 shows the numbering sequence of

these piles and Figure 8 shows the 3D

renditioned view of piling work sought to be

achieved. Proper planning was done for the

construction of these piles keeping in mind

the working space requirements at the site.

For construction of each pile, its survey

coordinates were staked on ground using the

control pillars and total station. Picture 5 and

6 shows the control pillars used for staking

the coordinates of the piles on the ground.

5. DRILLING AND CONCRETING OF

PILES

The DTH 300-01 model drilling rig, water

tank and air compressor mounted on Ashok

Leyland Truck was used for drilling of piles.

Picture 7 shows the drilling rig with water

tank and air compressor mounted on the

truck used for drilling of piles at the hybrid

pile foundation P3 location. The operation

of drilling rig was done by 2 operators and 2

assistants. Recoverable steel casing of

diameter 390 mm was first drilled into the

soil as a temporary support and thereafter

the drilling bit mounted on drilling rod was

rotated inside the steel casing over the

staked coordinates of pile. The diamond

button head drilling bit of diameter 340 mm

was used for drilling. The compressed air

and/or water was sent down towards the

drilling bit through the annular space in the

drilling rods for flushing out the drill

cutting/slush. The soil and rock was

removed by the rotary and/or percussion

(hammering) action of the rotating drill bit.

The depth of excavation was increased by

further additions of the drilling rod at the

ends. The length of the first drilling rod

attached to the drilling bit was 2 m and the

lengths of subsequent drilling rods were 1.5

m. After reaching the design depths as

indicated in the drawing, the drilled hole

was cleaned, the water was pumped out of

the drilled bore and the drilling bit was taken

out. The depth of the bore hole was checked

by conducting the soundness test. The

excavated material was disposed off. The

diameter of outer and inner piles was 350

mm. The lengths of the constructed outer

and inner piles were 29.325 m and 22 m.

The concrete chipping of these constructed

piles was done keeping minimum 50 mm

above the bottom of the top raft and bottom

pile cap in case of outer and inner piles

respectively. The final lengths of piles were

29.3m and 20 m for outer and inner piles

respectively. The maximum progress of

drilling of piles achieved in 1 day was 4

piles but generally the progress achieved in

a day was 2-3 piles. The theoretical

quantities of the reinforcement steel and

concrete of grade M40 for each outer and

inner pile are given in Table 1.

The reinforcement cage for the pile was

fabricated at the fabrication yard. Picture 8

shows the fabrication yard for fabrication of

reinforcement cage of piles of hybrid pile

foundation P3. Picture 9 shows the

formation of spiral reinforcement of pile.

Page 5 of 22

Picture 10 shows the inhibitor solution

application over the reinforcement of piles.

Picture 11 shows the loading of

reinforcement cage in truck for transporting

it to the site of hybrid pile foundation P3.

Picture 12 shows the lowering of

reinforcement cage in the drilled hole of the

pile of hybrid pile foundation P3. Picture 13

shows the closer look into the installation of

reinforcement cage into the bore hole.

For concreting of piles a special mix of M40

grade was developed with maximum

aggregate size of 10 mm. Table 3 shows the

constituents of concrete in M40 mix design.

The concreting of piles was done using

tremie pipe. The slump of concrete

measured at the site was generally 190 mm -

220 mm. Picture 14 shows the tremie pipe

attached to hopper at the top used for

concreting of piles. Picture 15 shows the

preparations being done for the tremie

concreting of pile. Picture 16 shows the

tremie concreting in progress for the pile.

Picture 17 shows the concrete cube samples

taken during tremie concreting of piles.

Table 4 shows the time cycle for the

construction of pile of hybrid pile

foundation P3.

6. CONSTRUCTION OF TOP RING

BEAM, BOTTOM PILE CAP AND

BOTTOM RING BEAM

After completion of construction of 98 outer

piles and 55 inner piles of hybrid pile

foundation P3, the excavation was started

around the hybrid pile foundation P3.

Picture 18 shows the excavation in progress

around the hybrid pile foundation P3. The

excavation was done inside the hybrid pile

foundation P3 upto the bottom of the top raft

thereby exposing the outer piles. Thereafter,

the chipping of concrete of 98 outer piles

above the bottom level of top raft was done

using the jack hammer. Picture 19 shows the

chipping of concrete of outer piles in

progress at hybrid pile foundation P3.

Thereafter, excavation was done in the

inside portion of outer piles upto the bottom

level of the top ring beam. The

reinforcement binding was then started for

the the top ring beam around the outer 98

piles. Thereafter M35 grade concreting was

completed using bucket mounted on long

boom PC 300 crane and subsequently curing

was done. The width and the depth of the

top ring beam were 600 mm and 750 mm

respectively. Picture 20 shows the

concreting in progress for the top ring beam

using bucket and crane arrangement. Picture

21 shows the completed top ring beam in

elevation. After completion of top ring

beam, the excavation was started in the

inside area of the top ring beam for reaching

the bottom level of the bottom pile cap. The

excavation was done using excavators,

breakers and long boom PC 300 machines.

Pictures 22, 23 and 24 shows the excavation

in progress at the hybrid pile foundation P3

using excavators, breakers and long boom

PC 300 machines. The middle ring beam

and shotcrete lining on the inside face was

not provided considering the safe and stable

site conditions during excavations. The top

of the inner piles above the bottom level of

the bottom pile cap was chipped off keeping

minimum projection of 50 mm above that

level. Picture 25 shows the chipping of

concrete of inner piles in progress at the

hybrid pile foundation P3. The diameter and

Page 6 of 22

depth of the bottom pile cap were 13.1 m

and 2 m respectively. Picture 26 shows the

arrangement for bending of reinforcement at

the site of hybrid pile foundation P3. The

reinforcement of the bottom pile cap was

transported to the site of work using Hydra

crane. Picture 27 shows the reinforcement

being carried to the site of work using hydra

crane. Pictures 28, 29 and 30 shows

reinforcement binding in progress at

different stages for bottom pile cap of hybrid

pile foundation P3. Picture 31 shows the

concreting in progress for bottom pile cap.

After completion of the construction of the

bottom pile cap the reinforcement binding of

the bottom ring beam was completed. The

width and the depth of the bottom ring beam

were 500 mm and 750 mm respectively.

Thereafter construction of bottom ring beam

was completed. Table 3 shows the

constituents of concrete mix design of grade

M35 and M40 used for the construction of

top ring beam, bottom pile cap and bottom

ring beam.

7. PCC INFILLING AND

CONSTRUCTION OF TOP RAFT

The PCC infilling of 1:3:6 was completed

from the top level of the bottom pile cap up

to the bottom level of the top raft. The depth

of PCC infilling was 8 m and the quantity of

PCC was 1056 cum. Picture 32 shows the

PCC infilling in progress using the funnel

and canvas chute arrangement. Picture 33

shows the competed PCC upto the bottom of

the top raft. On completion of PCC infilling

the process of construction of top raft was

started. The diameter and depth of the top

raft were 14 m and 3.2 m respectively.

Pictures 34 and 35 shows the reinforcement

binding in progress for the top raft of hybrid

pile foundation P3. Picture 36 shows the

completed top raft of hybrid pile foundation

P3.

8. REINFORCEMENT BINDING

The Bar Bending Schedule (BBS) was

prepared as per the approved drawings for

the piles, top ring beam, bottom pile cap,

bottom ring beam and top raft. The

reinforcement bars were then cut and bend

to the length, shape and numbers for each

bar mark/ID mark as given in the BBS. The

reinforcement bars were treated with anti

corrosive treatment by using inhibitor

solution. The reinforcement bars were then

tied in position to the spacing, lapping as

given in the BBS and in the approved

drawings. All reinforcing bars had to be

exactly placed in the position shown in the

drawings and had to be securely held in

position during placing of concrete by

galvanized steel binding wire not less than

18 SWG in diameter and conforming to IS

280 and by using stays, chairs, spacers,

metal hangers, supporting wires or other

approved devices at sufficiently close

intervals. Not more than 50 percent bars had

to be lapped at the same section i.e.

staggered lap splices. Lap splices are

staggered if the center to center spacing of

the splices is greater than or equal to 1.3

times the lap length. The distance between

the adjacent laps should be greater than or

equal to 150 mm.

9. FORMWORK

The piles of hybrid pile foundation P3 were

bored and cast in situ piles. The temporary

support of casing of internal diameter 390

Page 7 of 22

mm, thickness 10 mm and length of 2 m was

provided at the top only. When the caving in

of the sides of the bore hole happened, the

bore hole was filled with concrete and

drilling was resumed again after 24 hours.

The formwork of top and bottom ring beams

consisted of steel plates of dimensions 1.5 m

x 0.5 m and thickness 10 mm. These steel

plates were connected to each other by bolts

and laterally supported by channels and

props. Picture 20 shows the formwork

provided for the construction of top ring

beam.

The lateral support for the concreting of the

bottom cap was provided by the sides of

bore hole consisting of outer piles.

The formwork of the top raft consisted of

steel plates of dimensions 1.5 m x 0.5 m and

thickness 10 mm. These steel plates were

connected to each other by bolts and

laterally supported by channels, walers and

props. Picture 36 shows the formwork

provided for the construction of top raft.

10. CONCRETING METHODOLOGY

For the concreting of piles, the tremie

concreting methodology was adopted. The

diameter of the tremie pipe was 100 mm.

The tremie pipe was attached to the hopper

at its top on which concrete was fed from

the transit mixer. Picture 14 shows the

tremie pipe attached to hopper at the top.

The length of tremie pipe could be increased

by adding additional pipes. The concrete

was placed at the lower end of tremie pipe

keeping the lower end sufficiently deep into

the concrete which had been placed

previously but had not yet set. The

maximum size of aggregate in M40 mix was

kept as 10 mm to allow the free flow of

concrete through the tremie pipe of 100 mm.

After the placing of concrete was started the

lower end of the tremie pipe was to remain

within the top surface of plastic concrete in

order to allow the build up of concrete from

below instead of flowing over the surface.

For top and bottom ring beams, bucket and

crane concreting methodology was adopted.

The bucket of capacity 0.5 cum was attached

to the long boom PC 300 crane. The bucket

was filled with concrete from the transit

mixer and thereafter was moved to the site

of placement of concrete using the long

boom PC 300 machine.

The concreting of bottom cap was done

using three concreting methodologies i.e.

bucket and crane; pumps connected with

rigid pipes; funnel and canvas chutes. In the

pumps and rigid pipes methodology, the

concrete from the transit mixer was forced

into the rigid pipes through the concrete

pump. The other end of the rigid pipe was

connected to the flexible pipe which could

be moved around for placing the concrete

inside the reinforcement cage. In the funnel

and canvas chute arrangement, the concrete

from transit mixer was fed into the funnel

which was carried by gravity through the

canvas chutes to the location of placement

of concrete.

The concreting of the top raft was done

using rigid pipes and pumps. For details of

the concreting methodology adopted for the

top raft of hybrid pile foundation P3, the

readers are advised to refer paper by the

Author “CONSTRUCTION OF RAFT

FOUNDATIONS: THE CASE STUDIES

Page 8 of 22

OF RAFT FOUNDATIONS OF BRIDGE

NO. 43 AND 44 (CHENAB BRIDGE) AT

BAKKAL, USBRL PROJECT” published in

the IPWE proceedings 2019.

11. RESULTS

(i) Materials testing before concreting

The size, gradation and moisture content

tests for coarse aggregates were to be

conducted before each concreting day as

specified in the approved Quality Assurance

Plan (QAP) for civil works for Bridge No.

43. Similarly the tests for size, gradation, silt

content, moisture content of sand were to be

conducted as specified in the approved QAP

for civil works for Bridge No.43. All the

other tests on materials like cement,

aggregates, reinforcement bars, admixture,

water etc were carried out as per their

frequencies as specified in the QAPs for the

civil works for Bridge No.43. For

illustration purpose Table 5 shows the

results of sieve analysis of 10mm coarse

aggregate before the concreting of pile at

hybrid pile foundation P3.

(ii) Concrete Production at the batching

plant

The concrete for hybrid pile foundation P3

was produced at the batching plant of

capacities 30 cum per hour. The moisture

content of aggregates was determined and

the moisture corrections were incorporated

in the approved mix design at SSD

conditions. For illustration purpose Table 6

shows the moisture correction for concrete

mix of M40 grade before concreting of pile

of hybrid pile foundation P3. The calibration

of batching plant is to be done per month as

per the QAP for civil works for Bridge No.

43.

(iii) Cube strength test results

The cube samples were prepared at site

during concreting operations of hybrid pile

foundation P3 and thereafter taken to the

quality control laboratory at the site. Table 7

shows the 28 days cube strength test results

for the various concreting operations in

hybrid pile foundation P3.

(iv) Permeability test

The permeability test was conducted for the

concrete used in the construction of hybrid

pile foundation P3. For illustration purpose

Table 8 shows the results of permeability

test conducted for the pile of hybrid pile

foundation P3. Sample for permeability test

on concrete as per Appendix-G of IRS

Concrete Bridge Code was taken on

14.03.2018 for the pile no. 31 of hybrid pile

foundation P3. Test was conducted at

Quality Control Laboratory at Reasi as per

Appendix-G of IRS CBC on 15.04.2018 and

observations are given in Table 8. The

permissible value of permeability is 25 mm.

(v) Milestone Monitoring

The time periods pertaining to the milestone

achievements during the construction of

hybrid pile foundation P3 are presented in

Table 10.

12. CONCLUSIONS

(i) The workability of concrete as

measured by slump test was maintained as

per the design mix range/requirements of job

site in terms of the QAP for civil works for

Page 9 of 22

Bridge No. 43. For piles tremie concreting

was done. For top ring beam, bottom pile

cap, bottom ring beam and top raft, concrete

was poured in layers and each layer was

vibrated as it was placed.

(ii) After initial setting of top surface of

concrete, curing was started by sprinkling

with water, covering with wet hessian cloth

or ponding to reduce early dry shrinkage.

After the removal of the formwork the same

was covered with hessian cloth on the sides

and kept wet by sprinkling of water at

regular intervals to maintain the dampness

of the hessian cloth throughout the curing

period.

(iii) Quality of concrete used in the

construction of hybrid pile foundation P3 as

determined from the 28 days cube strength

test results as given in Table 7 and by

permeability test as given in Table 8 was in

the acceptable limits.

13. REFERENCES

(i) Indian Railway Standard

Concrete Bridge Code

(ii) IS 456:2000 Plain and

Reinforced concrete – Code of

Practice

(iii) IS 12070:1985(Reaffirmed in

1995) Code of Practice for

Design and Construction of

Shallow Foundations on Rocks

(iv) IS 2911-1-2 (2010) Design and

Construction of Pile

Foundations-Code of Practice,

Part 1: Concrete Piles, Section 2:

Bored Cast In -Situ Concrete

Piles

(v) IS 9012: 1978 (Reaffirmed in

2002) Recommended practice for

Shotcreting

(vi) IS 11309 (1985) Method of

Conducting Pull out test on

anchor bars and rock bolts

(vii) Data as provided at site and in

quality control laboratory at

Bakkal for Bridge No. 41, 42, 43.

(viii) Quality Assurance Plan(QAP)

for Civil Works for Bridge No.43

(ix) Method Statement for excavation

of Bridge 43 (A1 to P3) & Salal

Station Yard

(x) Report on Additional

Geotechnical Investigation for

Slope Stability of Bridge No. 43

on Katra – Dharam section of

USBRL Project

Table 1 Details of Hybrid Pile Foundation P3 - I

S.No. DESCRIPTION THEORETICAL QUANTITIES OF

CONCRETE (CUM) REINFORCEMENT (MT)

1 Single Outer Pile 2.821 1.266

2 Single Inner Pile 2.116 0.828

3 Total of all Piles 392.838 169.608

4 Top Ring Beam 18.941 7.019

5 Bottom Cap 262.232 88.56

6 Bottom Ring Beam 16.864 5.111

7 Top Raft 492.509 124.13

Page 10 of 22

Table 2 Details of Hybrid Pile Foundation P3 - II

DESCRIPTION GRADE OF CONCRETE

CLEAR COVER TO REINFORCEMENT

Piles M40 50 mm

Top Ring Beam M40 75 mm

Bottom Cap M35 75 mm

Bottom Ring Beam M40 75 mm

Top Raft M35 75 mm

Table 3 Concrete Mix Design for Hybrid Pile Foundation P3

CONSTITUENT

M35 GRADE FOR TOP RAFT, BOTTOM PILE CAP

M40 GRADE FOR PILES M40 GRADE FOR RING BEAMS

QUANTITY (Kg/cum) QUANTITY (Kg/cum) QUANTITY (Kg/cum)

Cement (OPC) 400 480 430

20 mm Coarse Aggregate 710 - 697

10 mm Coarse Aggregate 473 1080 465

Fine Aggregate 759 762 746

Water 152 158 155

Admixture 4.8 (Master Polyheed 8630

@1.2%)

5.28 (Master Polyheed 8630

@ 1.1%)

5.16 (Master Polyheed 8630

@1.2%)

Free Water Cement Ratio 0.38 0.329 0.36

Table 4 Time Cycle for Construction of Pile

S.No. DESCRIPTION TIME TAKEN

1 Average time for installation of Casing 45 Minutes

2 Average time for drilling of pile 6 Hours

3 Average time for installation of Reinforcement Cage in excavated bore hole of pile

4 Hours

4 Average time for lowering of tremie pipe to the bottom of the excavated bore hole of pile

1 Hour

5 Average time for concreting of pile 1 Hour 45 Minutes

Table 5 Sieve Analysis of 10mm Coarse Aggregate done before concreting of Pile

IS SIEVE SIZE (mm)

WEIGHT RETAINED (gm)

CUMULATIVE WEIGHT RETAINED (gm)

PERCENTAGE CUMULATIVE WEIGHT RETAINED

PERCENTAGE PASSING

IS 383- 1970 LIMIT

12.5 0 0 0 100 100

10 512 512 10.24 89.76 85-100

Page 11 of 22

4.75 4006 4518 90.36 9.64 0-20

2.36 442 4960 99.2 0.8 0-5

Pan 40 - - - -

Table 6 Moisture Correction for concrete Mix M40 before concreting at Hybrid Pile Foundation P3

BATCH WEIGHT FOR 1 M3 IN SSD CONDITION

CEMENT COURSE AGGREGATES FINE AGGREGATE

WATER ADMIXTURE

20 MM 10 MM

480 0 1080 762 158 5.28

BATCH WEIGHT FOR 1 M3 AFTER MOISTURE CORRECTION

Water Absorption(%) - 0.36 0.52 1.28 - -

Moisture Content (%) - 0 0.2 2.8 - -

Moisture Adjustment(%)

- -0.36 -0.32 1.52 - -

Difference in Weight due to Moisture

Content (Kg)

- 0 -3.46 11.58 - -

Corrected Batch Quantity Kg/m3

480 0 1076 774 150 5.28

Table 7 Cube Strength Test Results for the Hybrid Pile Foundation P3

DESCRIPTION NUMBER OF SAMPLES TAKEN DURING ENTIRE

CONCRETING

RANGE OF COMPRESSIVE

STRENGTH VALUES

OBSERVED(MPa)

MEAN OF COMPRESSIVE

STRENGTH VALUES

OBSERVED (MPa)

STANDARD DEVIATION OF COMPRESSIVE

STRENGTH VALUES OBSERVED (MPa)

Piles (28 Days) 153 42.58 – 55.70 51.06 2.50

Piles (7-Days) 153 32.14 – 44.5 39.42 2.18

Top Ring beam 3 53.73 - 55.55 54.37 1.02

Bottom Cap 9 46.17-52.6 49.26 2.00

Bottom Ring beam

3 52.22-53.57 52.74 0.73

Top Raft 10 48.69-50.8 49.88 0.69

Page 12 of 22

Table 8 Permeability test result for Pile No. 31 of Hybrid Pile Foundation P3

SPECIMEN NUMBER

TEST START DATE

TIME TEST END DATE

TIME PRESSURE APPLIED(BAR)

PERMEABILITY MEASURED

VALUE (mm)

AVERAGE VALUE (mm)

1 11.04.2018

16.00 15.04.2018 16.00 1st 48 Hours: 1 Bar

Next 24 Hours: 3 Bar

Next 24 Hours: 7 Bar

6

6.67 2 11.04.2018

16.00 15.04.2018 16.00 8

3 11.04.2018

16.00 15.04.2018 16.00 6

Table 10 Milestone achievements in construction of Hybrid Pile Foundation P3

S.No. DESCRIPTION DATE OF STARTING

DATE OF COMPLETION

NUMBER OF DAYS TAKEN

1 Excavation for Hybrid Pile Foundation P3 01.10.2017 16.02.2018 51

2 Shotcrete 06.10.2017 21.02.2018 50

3 Rock Bolting 03.10.2017 18.02.2018 49

4 Piling for Hybrid Pile Foundation P3 17.02.2018 15.05.2018 88

5 Chipping of Outer Piles (98 no.s) 15.05.2018 31.05.2018 16

6 Excavation upto bottom level of top ring beam 15.05.2018 20.05.2018 5

7 Construction of top ring beam 31.05.2018 10.06.2018 11

8 Excavation upto bottom of bottom pile cap 22.06.2018 18.07.2018 27

9 Chipping of inner piles (55 no.s) 19.07.2018 25.07.2018 6

10 Construction of bottom pile cap 26.07.2018 18.08.2018 23

11 Construction of bottom ring beam 19.08.2019 21.08.2018 2

12 PCC infill from top of bottom pile cap and upto the bottom of top raft

20.08.2018 30.08.2018 10

13 Construction of top raft 31.08.2018 30.09.2018 30

Page 13 of 22

Table 9 Survey Coordinates of Piles of Hybrid Pile Foundation P3

Page 14 of 22

Fig.1 Hybrid Pile Foundation P3 in Plan

Fig.2 Hybrid Pile Foundation P3 in Elevation

Fig.3 Plan at the top raft level of Hybrid Pile Foundation P3

Fig.4 Plan at the Ring beam level of Hybrid Pile Foundation P3

Fig.5 Excavation in Cutting for Hybrid Pile Foundation P3 in Plan

Fig.6 Excavation in Cutting for Hybrid Pile Foundation P3 in Elevation

Page 15 of 22

Fig. 7 Numbering Sequence for drilling and construction of piles

Fig. 8 3D View of drilled piles sought to be achieved

Page 16 of 22

Picture 1 Geological L section from Hybrid pile foundations A1 – P3

Picture 2 Geological Cross Section at Hybrid Pile Foundation P3

Picture 3 Excavation in Progress at Hybrid Pile Foundation P3 Location

Picture 4 Ground Level reached for starting drilling of piles at Hybrid Pile Foundation P3

Picture 5 Control Pillar -I at Hybrid Pile Foundation P3 Location

Page 17 of 22

Picture 6 Control Pillar -II at Hybrid Pile Foundation P3 Location

Picture 7 Drilling Rig with Air Compressor, water tank mounted on Truck

Picture 8 Fabrication Yard for Reinforcement Cage of Piles of Hybrid Pile Foundation P3

Picture 9 Fabrication of Spiral Reinforcement of Piles

Picture 10 Inhibitor Solution Application to Reinforcement at Fabrication Yard for Piles

Picture 11 Transportation of Reinforcement Cage of Pile from Fabrication Yard to Work Site

Page 18 of 22

Picture 12 Lowering of Reinforcement Cage into the Drilled Hole of Pile

Picture 13 Installation of Reinforcement Cage into the Drilled Hole of Pile in Progress

Picture 14 Tremie Pipe Attached to hopper at the top used for Concreting of Piles

Picture 15 Preparations for Tremie Concreting of Pile in Progress at Hybrid Pile Foundation P3

Picture 16 Tremie Concreting for Pile in Progress at Hybrid Pile Foundation P3

Picture 17 Concrete Cube Samples taken during Tremie Concreting of Pile

Page 19 of 22

Picture 18 Excavation in Progress around Hybrid Pile Foundation P3 after construction of all piles

Picture 19 Chipping of Concrete of Outer Piles in Progress using Jack Hammer

Picture 20 Concreting in Progress for top ring beam of Hybrid Pile Foundation P3

Picture 21 View in Elevation of completed top ring beam of Hybrid Pile Foundation P3

Picture 22 Excavation in Progress inside the top ring beam of Hybrid Pile Foundation P3-I

Picture 23 Excavation in Progress inside the top ring beam of Hybrid Pile Foundation P3-II

Page 20 of 22

Picture 24 Excavation in Progress inside the top ring beam of Hybrid Pile Foundation P3-III

Picture 25 Chipping of Concrete of Inner Piles in Progress

Picture 26 Arrangements for Reinforcement Bending

Picture 27 Transportation of Reinforcement of Bottom Pile Cap

Picture 28 Reinforcement Binding in Progress at Bottom Cap-I

Picture 29 Reinforcement Binding in Progress at Bottom Cap-II

Page 21 of 22

Picture 30 Reinforcement Binding Completed at Bottom Pile Cap

Picture 31 Concreting in Progress at Bottom Pile Cap

Picture 32 PCC infilling in Progress at Hybrid Pile Foundation P3

Picture 33 PCC infilling Completed at Hybrid Pile Foundation P3

Picture 34 Reinforcement Binding in Progress at Top Raft of Hybrid Pile Foundation P3

Picture 35 Reinforcement Binding in Progress at Top Raft of Hybrid Pile Foundation P3

Page 22 of 22

Picture 36 Construction of top raft of Hybrid Pile Foundation P3 Completed