0

2013

L&T construction project

1

Report on:

CONSTRUCTION OF SEGMENTS

Submitted on: 25-06-2013

Submitted by:

MAHANKALI ROHITH

1011110133

SRM UNIVERSITY,

KATTANKULATHUR, TAMIL NADU.

2

EXECUTIVE SUMMARY

On my assignment of the project in precast yard (chinthal). I am able to gain knowledge

about the construction procedure of the foundation in major constructions. This project is

being carried forward under the helpful belt of engineers and managers of the Larsen &

Toubro group. My internship covered a period of 15 days where I tried to gather practical

knowledge as much as possible. During my tenure segments work was going on, thus I got

opportunity to learn about segments. My report is based on the following sections:

A. Project Synopsis

B. Sequence of work

C. Quality Control and associated tests in Q.C. lab

D. Batching plant

E. Description of the site work

F. Planning

G. Safety Department

3

A. PROJECT SYNOPSIS

The metro project is being carried out under the vigilance of the senior engineers and the

project manager who maintains the technical record of the on going project. The work goes

on 24 hours. The work in the site consists of 3 bays

Bay 1

Bay 2

Bay 3

The objective of this Construction Procedure is for efficient execution to cast segments at

casting yard and formulate as a summary of all quality related activities required to meet the

terms of the contract as per the approved drawings & relevant technical specifications.

B. SEQUENCE OF WORK

PIER HEAD SEGMENTS (end diaphragm):

Alignment of soffit and outer forms

Alignment of bulked head on both sides

Surveying on segments

Cutting ,bending and tying of reinforcement

Lifting and placing of rebar cage along with sheathing pipe

Alignment of HDPE sheathing pipe

Aligning and setting of internal shutter

Providing and fixing the inserts of lifting holes and drainage spouts

Final survey and rebar checking

Now laying and compacting is done

Then finishing of concreting is done

Curing process

Allow setting of concrete to gain 20 Mpa strength for removal of form work

De molding of external shutter and removal of internal shutter

Shifting of pier head segment from casting bed to stacking bed after gaining 25 Mpa

strength

4

INTERMEDIATE SEGMENTS :

Alignment of soffit and Outer form

Alignment of bulkhead on one side

Shifting and alignment of match cast segment

Surveying is done

Application of formwork releasing agent/ deboning agent to shutter and match cast

face

Cutting, Bending & Tying of Reinforcement

Lifting and placing of rebar cage along with sheathing pipe.

Alignment of HDPE sheathing pipe.

Aligning & setting of internal shutter.

Providing and fixing inserts for drainage spouts, lifting holes, temporary pre-stressing

provisions, if required

Final survey and rebar checking

Laying, compacting & finishing of concrete

Curing

Allow setting of concrete to gain 20 MPa strength for removal of formwork

Loosening of external shutter and removal of internal shutter.

Lifting of match cast segment and shifting to stock yard after gaining 25MPa strength.

Alignment of temporary bulk head and the above said sequence shall continue till

completion of span

C. LABORATORY TESTS

C.1 TEST ON AGGREGATES:

Gradiation (Sieve) Analysis

Aggregate Impact value test

Flakiness index

Elongation index

Specific gravity

Water absorption

Moisture context

Bulk density

5

C.2 TESTS OBSERVED ON SOIL:

Grain size (sieving) analysis

Liquid limit and plastic limit

Proctor density

Free shell index

C.B.R ( calfornia bearing ratio)

Chemical test on soil and water.

C.2.1 Cone Penetrometer:

Used to calculate Liquid Limit of the soil.

For non-plastic soil.

Deep penetration is made

No blows are provided.

Water content corresponds to 20 mm penetration.

C.3 TEST ON CONCRETE:

Slump Test

Slump test is done to determine the workability of concrete. This test is carried out

before doing concreting. Concrete is filled in the slump cone in 3 layers After

filling each layer it is compacted by a 16mm diameter tamping rod 25 times and

thus all 3 layers are filled up to the top of the cone. Then the cone is lifted up

gradually and the concrete is allowed to drop down. The slump is the drop in level

of concrete mass within the slump cone from top of the cone. For piling the slump

should be within the range of 150mm (minimum) to 200mm (maximum) as per

IS:456

Cube Test

Cube test is done for concrete to determine its compressive strength. The

concrete cube is made in a mould of 15 cm cube and tested in a machine called

compression testing machine Concrete cube is prepared and cured underwater

and tested after 28 days to determine final compressive strength.

6

C.4 TEST ON CEMENT:

Fineness test

Standard conistation

Initial setting time

Final setting time

Soundness test

Compressive strength of mortor

CONCRETE INGREDIENTS PER CUBIC METER:

Ingredients of concrete source of supply M 40

(pier)

M 45

(segments)

Mix code CTM 135

(SC)

CTM272829

(SC)

OPC 53 grade (kg) Ultra Tech OPC 53 grade,

Malkhed

330 435

Flyash (kg) NTPC -ramagundam 90 85

Total cementitious (kg) OPC + Flyash 420 520

Coarse Aggregate- Fraction 1 (kg)-

20 mm (dry)

L&T Crusher- Sulthanpur 584 575

Coarse Aggregate- Fraction 1 (kg)-

10 mm (dry)

L&T Crusher- Sulthanpur 480 472

Fine Aggregate- Crushed stone

sand (kg) (dry)

L&T Crusher- Sulthanpur 713 702

Total water (kg) Chilled manjera /

Borewell water

185.5 163.9

Free water- cementitous ratio - 0.41 0.29

Cemical admixture(kg), Maximum

allowable dosage

BASF`s Glenium B233 2.60 4.16

7

D. BATCHING PLANT

Located behind the quality control laboratory, the batching plant is for concreting and

concrete is produced.

With the progress of on-going layout of the segments ,parapet walls the structural design is

tested here and respectively the prototype is carried along the main site.

Relevant information about Batching plant operation.

Machine used CP 30;Schwing Statter, 30 cm(hour capacity)

Production capacity per cycle 0.5 m3

Capacity of a RMC truck 6 m3

Sand used(zone 2) Passed through 4mm sieve (or) <= 5mm

Stone chips used 20mm & 10mm

Concrete temperature <320C

Admixture Sikament(naphthalene based)

The following types of concrete used:

PIER M40

PIER CAP M50

SEGMENT M45

STATION PIER M60

8

E. DESCRIPTION OF SITE WORK:

The metro project is being carried out under the vigilance of the senior engineers and the

project manager who maintains the technical record of the on-going project. The segments

are divided into

S1 - 1.7 m (pier head segment)

S2 - 3m

S3 - 3m

S4A - 3m

S4 - 3m

Segment width is of 8.8m

In S1- segment (1.7m) – 1m is of solid part and 0.7 m freely left part.

S1 -01 and S2-02 are pier head segments

Remaining all are intermediate segments

For 31m span , arrangements of segments is as follows :

S1-01 S2-02 S3-03 S4-04 S4-05 S4-06 S4-07 S4-08 S3-09 S2-10 S1-11

9

KEY PLAN:

For 31 m span:

S1

S2

S3

S4

S4

S4-

A

S4

S4

S3

S2

S1

For 28 m span:

S1

S2

S3

S4

S4

S4-

A

S4

S3

S2

S1

For 25 m span:

S1

S2

S3

S4

S4-

A

S4

S3

S2

S1

For 22 m span:

S1

S2

S3

S4

S4-

A

S3

S2

S1

For 19 m span:

S1

S2

S3

S4-

A

S3

S2

S1

10

A. Sequence of Casting for Pier Head Segments - Segment S1-01 / S1-11

1. Leveling the form work free / fixed end and support for bearing outstand

2. Closing the external form work of pier segment

3. Application of mould releasing agent

4. Cutting, Bending & Tying of Reinforcement

5. Lifting and placing of reinforcement cage

6. Fixing of guide cones on bulkhead

7. Fixing of first bulkhead in the pier side

8. Fixing of second bulk head in the match cast side

9. Profiling the sheathing pipe as per the co ordinates

10. Aligning & setting of internal shitters in position

11. Jacking and fixing up of internal form work

12. Installations of all inserts and lifting, temporary stressing arrangements etc.

13. Laying, compacting & finishing of concrete for segment

14. Allow setting of concrete for removal of formwork. Curing to be done during setting.

15. De-shuttering of internal form and bulkhead.

16. Shifting of pier head segment from Pierhead casting bed to stacking bed after gaining

25MPa

strength

17. Curing of segment for 14 days.

B. Sequence of Casting for Intermediate Segment (Long Line) - Straight span:

The pier head segment shall be cast first on independent bed and same shall be brought to

long

line bed to form the match cast segment for casting the adjacent segment. The sequence of

casting for intermediate segments in long line method is as follows

For typ. Segment S2-02 / S2-10

1. Aligning the soffit formwork for straight span

2. Lifting and positioning of S1 (Free and fixed) segment to match cast location for S2-02

and

S2-10 segment

3. Application of de-bonding agent at the match cast side

4. Close the external form work

5. Cleaning of shutter and application of mould releasing agent

11

6. Placing of rubber cone in the match cast segment sheathing pipe for sealing of joint at

matchcast face.

7. Cutting Bending & Tying of Reinforcement

8. Lifting and placing of reinforcement cage

9. Placing and fixing of bulk head

10. Installation and profiling of sheathing pipe as per the co-ordinates.

11. Placing of internal form work.

12. Installation of all inserts for lifting, temporary stressing arrangements.

13. Final survey.

14. Casting of segments (S2-02).

15. Allow setting of concrete. Curing to be done during setting.

16. De-shuttering after the requisite strength, external and internal form work with bulkhead.

17. Curing of segment for 14 days.

18. Internal shutter move from S2-02 to S2-10 and with above sequence casting of S2-10 to

be

carried out.

For typ. segment S3-03 /S3-09

1. Shifting of internal shutters on S3-03 and cast against S2-02 and end stopper.

2. Placing of bulkhead and alignment.

3. Placing of rubber cone in the match cast segment sheathing pipe for sealing of joint at

matchcast face.

4. Cutting Bending & Tying of Reinforcement

5. Lifting & placing of rebar cage.

6. Installation and profiling of sheathing pipe as per the co-ordinates.

7. Placing of internal form work.

8. Installation of all inserts for lifting, temporary stressing arrangements.

9. Final survey.

10. Casting of segments (S3-03)

11. Allow setting time of concrete. Curing to be done during setting.

12. De-shuttering after the requisite strength (external and internal formwork with bulkhead).

13. Curing of segment for 14 days.

14. Same sequence follows as parallel activity forecasting for casting S3-09 also.

For typ. Segment S4-04 / S4-08, S4-05/S4-07

Casting of above said segments shall be followed as sequence mentioned for segments S3/S9

For typ. segment S4-06

After completing S4-07 internal shutters shall move from S4-07 to S4-06 and concreting of

S4-06

shall be carried out with above sequence

12

C. Sequence of Casting for Intermediate Segment (Long Line) - Curved span:

For curved span also pier head segment casted on Pierhead Mould and same shall be brought

to

long line mould to form the match cast segment for casting the adjacent segment, the

sequence of

casting for intermediate segments in long line bed as follows:

For typ. Segment S2-02 / S2-10

1. Aligning of soffit formwork for curve span of required radius of curvature.

2. Shifting of S1-01 /S1-11 segments to match cast location for casting S2-02/S2-10.

3. Aligning of temporary bulk head.

4. Applying of de-bonding agent over match cast segment.

5. Cutting, Bending & Tying of Reinforcement

6. Closing of external form work.

7. Placing of rubber cone in the match cast segment sheathing pipe for sealing of joint at

matchcast face.

8. Lowering of rebar cage.

9. Installation of sheathing pipe.

10. Profiling of sheathing pipe as per co–ordinates.

11. Moving of internal form work.

12. Jacking of internal form work.

13. Installation of all inserts for lifting/temporary stressing arrangements.

14. Final survey.

15. Casting of segment (S2-02).

16. Allow setting of the concrete. Curing to be done during setting.

17. De-shuttering of internal form work after requisite strength.

18. Curing of segment for 14 days.

19. Internal form work shall move from S2-02 to S2-10 and casting of S2-10 shall be carried

out

with respect to above sequence.

For typ. segments S3-03 / S3-09

1. Shifting of internal shutter on S3-03 and cast against S2-02 and end stopper.

2. Placing of bulk head and alignment.

3. Placing of rubber cone in the match cast segment sheathing pipe for sealing of joint at

matchcast face.

4. Cutting, Bending & Tying of Reinforcement

5. Lowering of rebar cage.

6. Installation and profiling of sheathing pipe as per co-ordinates

7. Placing of internal form work& alignment

8. Installation of all inserts for lifting, temporary stressing arrangements.

9. Final survey.

10. Casting of segments (S3-03).

11. Allow setting time of concrete. Curing to be done during setting.

12. De-shuttering after requisite strength (internal form& bulk head).

13. Curing of segment for 14 days.

14. Same sequence follows as parallel activity for casting S3-09 also.

For typ. segments S4-04 / S4-08, S4-05/S4-07

13

Casting of above said segments shall be followed as sequence mentioned for segments S3/S9

For typ. segments S4-06

After completing S4-07 internal shutters shall move from S4-07 to S4-06 and concreting of

S4-06

shall be carried out with above sequence

F. PLANNING

Planning department is the nucleus of the project work. The planning department works

mainly in two phases:

PROJECT MANAGEMENT

CONTROL SYSTEM

PROJECT MANAGEMENT:

This system is mainly governed by the contract system. It also consists of two parts:

1. Financial part: - this wing mainly focuses on the optimum utilization of the budget

limit provided in the tender.

2. Technical part: - this wing looks after the procedure and progress of the project and

the quantity and quality of the materials required keeping in mind the financial

restriction.

The GCC (general condition of contract) is included here.

This management also looks after the schedule of the project i.e. how the project will work

keeping in mind the time factor. In every project operated by L&T there are 10 schedules

mostly (S0-S10) and some of the schedule are as follows:

Invoicing schedule

Plant and machinery schedule

Staff schedule

Materials schedule

14

CONTROL SYSTEM:

The main principle governing the control system is the reconciliation i.e. suppose a particular

work moves out of the prescribed schedule then how it can be adjusted with the remaining

schedule so that the project totally completes in the prescribed tenure.

Now in order to reconcile or to have a close watch on the work monitoring system is

followed and it is of 4 types:

Daily progress report(DPR)

Weekly progress report(WPR)

Monthly progress report(MPR)

Final completion report

TERMINOLOGIES:

1. ROTE(return on talent employed): reports the utilization of optimum limit of the

skilled man force on the project site along with the rate of work progress. It also

checks the efficiency of the workers in different field and schedule them accordingly

to the project progress.

2. ROCE(return on capital employed): reports the efficient utilization of the capital

according to the pre-planned schedule of the project progress and reports for plus or

minus of the force limit as per progress.

15

G. SAFETY AT CONSTRUCTION SITE

All Safety measures are taken to ensure basic discipline in a construction site as a compulsory

act. A number of safety measures for on-site construction workers were laid in site safety

plan.

With workers at site of this project, Safety Management was in place. They care for an

individual life. To ensure this safety a board of safety council have been vocationally trained

and alerted on site. They have several sections.

These include:

Incorporation of a Safety Policy as a commitment by the top management.

Formulation and documentation of various procedures for safety.

Development of a detailed Health, Safety and Environment (HSE) manual to be

followed at all construction sites, including mishap reporting and investigation.

Sharing of best practices with external agencies such as British Council, Loss

Prevention Association of India, National Safety Council, consultants and other

government agencies.

In-house training and education at construction sites and at head office.

Safety organisation with qualified Safety Professionals who help various Business

Units in improving safety conditions at construction sites.

At L&T, safety is integrated into all work practices. Based on their extensive experience, they

have also developed safety manuals, training and education programmes that form a

comprehensive Environmental and Safety management system, applicable to all their

projects. Every L&T subcontractors and business partners are asked to adopt their Safety

Policy.

16

EPILOGUE

With effective observation we come to the conclusion of an overall knowledge gain about the

metro rail segments.

Although complete structural details could not be gained due to short span of time but an

overview of the foundation construction was all we could gather.

RECOMMENDATIONS/REFLECTIONS:

- The management of the works that are being carried out is appreciable.

- Bare electric cables are there on the site which might be really dangerous and cause

accidents

The report would not be completed without adequate provision of data by the following

persons:

- Soman (ass. Project manager)

- Sachin (sr.eng)

- Krishnam raju (sr.eng)

- Santhosh (eng)

- Santhosh .v

- Laxman rao

- Gopal Krishna

- Vamshi

I thoroughly enjoyed the company of the seniors and also all the staff members. All the staffs

are helpful and their eagerness proves the healthy environment among the company staffs.

Overall i enjoyed a comfortable stay, healthy company, and quality knowledge and enjoyable

experience here.

Sincere thanks to Larsen and Toubro.