GAMMON INDIA LIMITEDCONSTRUCTION OF NEW BRAHMAPUTRA BRIDGE PROJECT

NEAR GUWAHATI ON NH-31 IN ASSAM

VOCATIONAL TRAINING

PROJECT REPORT

NAME- RAHUL TAMSOY

SEMESTER- 4TH

COLLEGE- NATIONAL INSTITUTE OF TECHNOLOGY, DURGAPUR

ACKNOWLEDGEMENT

I would like to express my special thanks of gratitude to my Project Advisor Mr. Arup Kumar Sharma and Mr. Ravinish Kumar who gave me the golden opportunity to do vocational training on this wonderful project and also helped in learning a lot of new things.

Secondly I like to thank my family and friends for helping me a lot in finishing this project within limited period.

I am making this project not only for good grades but also to increase my knowledge.

INTRODUCTION

Seeing the current increase in the traffic condition and increase in the age of the famous Saraighat Bridge on NH-31, the construction major Gammon India has bagged the contract for fifth bridge over Brahmaputra River at Guwahati with the cost of Rs 238 crore.

The bridge is constructed 40m south of existing Saraighat bridge. The bridge, which will connect the city’s south and north banks, is expected to reduce the pressure of traffic on Saraighat bridge.

Joshi said construction of the flyover at Jalukbari traffic intersection and widening of National Highway 31 are likely to be over by November this year.

The flyover at Jalukbari will touch the approach of the bridge and the existing roads. The flyover will be 243 metres long and have six lanes. Each three-lane carriageway will have separate foundations, substructure and superstructure.

Currently, commuters travelling on the snarl-ridden stretch from Jalukbari to the existing two-lane Saraighat bridge are facing a harrowing time. This problem will be solved when the new bridge is made and the development of the Jalukbari junction is complete.

The second bridge is a part of the East-West corridor project. The total length of the East-West corridor in Assam is 670km, of which 639km is with the National Highway Authority of India (NHAI).

Till January 2014, 431km of the East-West corridor has been completed, which includes four packages from Nagaon-Daboka-Lanka-Udali section.

According to an NHAI source, another 63km is expected to be finished by March 2013.

“Five more packages are likely to be completed by June 2013 and another three packages are likely to be completed by December 2014.

“All the problems being encountered in implementation of the East-West corridor have been resolved and work in all the packages are currently on in full swing,” the source said.

The NHAI was facing a host of problems during construction, including land acquisition trouble, obtaining forest and environment clearances and shifting of public utilities like telephone and electricity poles.

The Centre has cleared the conversion of the 178km stretch of National Highway 37 from Numaligarh to Dibrugarh into a four-lane road, said Union minister for road transport and highways C.P.Joshi.

CONTRACT DETAILS

Job : Construction of New Brahmaputra Bridge along with

Grade Separator and Signal free crossing at Jalukbari

On NH-31 and NH-37 in Assam

Contract Package : EW-II (AS 28)

Client : National Highway Authority of India (MORT&H)

Design Consultant : Span Consultant

Proof Consultant : IIT Delhi

PMC Consultant : Mott McDonald Ptv. Ltd.

Contractor : Gammon India Ltd.

Contact Period : 42 Months

Initial Contract Value : Rs 238.34cr

Revised Contract Value: Rs 309.56cr (including Jalukbari Crossing)

Type of Contract : Item Rate

Date of LOA : 31st May 2006

Contractual Date of Completion :21st April 2010

Revised Jalukbari Crossing added in this Contract : Rs 138.00 cr

ROW cleared for construction of Jalukbari signal free Crossing : June 2011

QUALITY LAB TEST

1. COARSE AGGREGATE1. Gradation of coarse aggregate

All-in-aggregate gradation

2. Aggregate Impact Value.

This test is done to determine the aggregate impact value of coarse aggregates as per IS: 2386 (Part IV) – 1963.

The apparatus used for determining aggregate impact value of coarse aggregates is

Impact testing machine conforming to IS: 2386 (Part IV)- 1963,IS Sieves of sizes – 12.5mm, 10mm and 2.36mm,

A cylindrical metal measure of 75mm dia. and 50mm depth, A tamping rod of 10mm circular cross section and

230mm length, rounded at one end and Oven.

Preparation of sample

i) The test sample should conform to the following grading:

– Passing through 12.5mm IS Sieve – 100%

– Retention on 10mm IS Sieve – 100%

ii) The sample should be oven-dried for 4hrs. at a temperature of 100 to 110oC and cooled.

iii) The measure should be about one-third full with the prepared aggregates and tamped with 25 strokes of

the tamping rod.

A further similar quantity of aggregates should be added and a further tamping of 25 strokes given. The

measure should finally be filled to overflow, tamped 25 times and the surplus aggregates struck off, using a

tamping rod as a straight edge. The net weight of the aggregates in the measure should be determined to the

nearest gram (Weight ‘A’).

Procedure to determine Aggregate Impact Value

i) The cup of the impact testing machine should be fixed firmly in position on the base of the

machine and the whole of the test sample placed in it and compacted by 25 strokes of the tamping

rod.

ii) The hammer should be raised to 380mm above the upper surface of the aggregates in the cup and

allowed to fall freely onto the aggregates. The test sample should be subjected to a total of 15 such

blows, each being delivered at an interval of not less than one second.

Reporting of Results

i) The sample should be removed and sieved through a 2.36mm IS Sieve. The fraction passing

through should be weighed (Weight ‘B’). The fraction retained on the sieve should also be weighed

(Weight ‘C’) and if the total weight (B+C) is less than the initial weight (A) by more than one gram,

the result should be discarded and a fresh test done.

ii) The ratio of the weight of the fines formed to the total sample weight should be expressed as a

percentage.

Aggregate impact value = (B/A) x 100%

iii) Two such tests should be carried out and the mean of the results should be reported.

3. Flakiness Index and elongation index

Flakiness Index is the percentage by weight of particles in it, whose least dimension (i.e. thickness) is less than three-fifths of its mean dimension. Elongation Index is the percentage by weight of particles in it, whose largest dimension (i.e. length) is greater than one and four-fifths times its mean dimension.

Flaky and elongated particles may have adverse effects on concrete and bituminous mix. For instance, flaky and elongated particles tend to lower the workability of concrete mix which may impair the long-term durability. For bituminous mix, flaky particles are liable to break up and disintegrate during the pavement rolling process.

4. Absorption Test

This test helps to determine the water absorption of coarse aggregates as per IS: 2386 (Part III) –

1963. For this test a sample not less than 2000g should be used. The apparatus used for this test

are :-

Wire basket – perforated, electroplated or plastic coated with wire hangers for suspending it from

the balance, Water-tight container for suspending the basket, Dry soft absorbent cloth – 75cm x

45cm (2 nos.), Shallow tray of minimum 650 sq.cm area, Air-tight container of a capacity similar to

the basket and Oven.

Procedure to determine water absorption of Aggregates.

i) The sample should be thoroughly washed to remove finer particles and dust, drained and then

placed in the wire basket and immersed in distilled water at a temperature between 22 and 32oC.

ii) After immersion, the entrapped air should be removed by lifting the basket and allowing it to drop

25 times in 25 seconds. The basket and sample should remain immersed for a period of 24 + ½ hrs

afterwards.

iii) The basket and aggregates should then be removed from the water, allowed to drain for a few

minutes, after which the aggregates should be gently emptied from the basket on to one of the dry

clothes and gently surface-dried with the cloth,transferring it to a second dry cloth when the first

would remove no further moisture.The aggregates should be spread on the second cloth and

exposed to the atmosphere away from direct sunlight till it appears to be completely surface-dry.The

aggregates should be weighed (Weight ‘A’).

iv) The aggregates should then be placed in an oven at a temperature of 100 to 110oC for 24hrs. It

should then be removed from the oven, cooled and weighed (Weight ‘B’).

Formula used is Water absorption = [(A – B)/B] x 100%.

Two such tests should be done and the individual and mean results should be reported. A sample

proforma for the record of the test is

2. FINE AGGREGATE1. Gradation of Fine Aggregate

Zone distribution of Fine aggregate

2. CONCRETE TEST

1. Cement test

AIM

To find the compressive strength of standard cement sand mortar cubes.

APPARATUS

7.06cm cubes moulds (50cm2 face area), apparatus for gauging and mixing mortar, vibrator, compression testing machining etc.

PROCEDURE

Take 200gm of cement and 600gm of standard sand in the proportion 1:3 by weight) in a pan. (The standard sand shall be of quartz, of light, grey or whitish variety and shall be free from silt. The sand grains shall be angular, the shape of grains approximating to the spherical form, elongated and flattened grains being present only in very small quantities.

Standard sand shall pass through 2mm IS sieve and shall be retained on 90 microns IS sieve with the following particle size distribution.

Mix the cement and sand in dry condition with a trowel for 1minitues and then add water. The quantity of water shall be (p/4+3)% of combined weight of cement and sand where, p is the % of water required to produce a paste of standard consistency determined earlier. Add water and mix it until the mixture is of uniform colour. The time of mixing shall not be < 3 minutes & not > 4 minutes. Immediately after mixing the mortar, place the mortar in the cube mould and prod with the help of the rod. The mortar shall be prodded 20 times in about 8 sec to ensure elimination of entrained air. If vibrator is used, the period of vibration shall be 2minitues at the specified speed of 12000+-400 vibrations /minutes. Then place the cube moulds in temperature of 27±2o C and 90% relative humidity for 24 hours.After 24 hours remove the cubes from the mould and immediately submerge in clean water till testing. Take out the cubes from water just before testing. Testing should be done on their sides without any packing. The rate of loading should be 350 kg/cm2/minute and uniform. Test should be conducted for 3 cubes and report the average value as the test result for both 7day and 28 day compressive strength.

RESULT

Compressive strength at 7 days =……….N/mm2

Compressive strength at 28 days =……….N/mm2

2. Concrete test

Compressive strength of concrete: Out of many test applied to the concrete, this is the utmost important which gives an idea about all the characteristics of concrete. By this single test one judge that whether Concreting has been done properly or not. For cube test two types of specimens either cubes of 15 cm X 15 cm X 15 cm or 10cm X 10 cm x 10 cm depending upon the size of aggregate are used. For most of the works cubical moulds of size 15 cm x 15cm x 15 cm are commonly used.

This concrete is poured in the mould and tempered properly so as not to have any voids. After 24 hours these moulds are removed and test specimens are put in water for curing. The top surface of these specimen should be made even and smooth. This is done by putting cement paste and spreading smoothly on whole area of specimen.

These specimens are tested by compression testing machine after 7 days curing or 28 days curing. Load should be applied gradually at the rate of 140 kg/cm2 per minute till the Specimens fails. Load at the failure divided by area of specimen gives the compressive strength of concrete.

Following are the procedure for Compressive strength test of Concrete Cubes

APPARATUS

Compression testing machine

PREPARATION OF CUBE SPECIMENS

The proportion and material for making these test specimens are from the same concrete used in the field.

SPECIMEN

6 cubes of 15 cm size Mix. M15 or above

MIXING

Mix the concrete either by hand or in a laboratory batch mixer

HAND MIXING

(i)Mix the cement and fine aggregate on a water tight none-absorbent platform until the mixture is thoroughly blended and is of uniform color

(ii)Add the coarse aggregate and mix with cement and fine aggregate until the coarse aggregate is uniformly distributed throughout the batch

(iii)Add water and mix it until the concrete appears to be homogeneous and of the desired consistency

SAMPLING

(i) Clean the mounds and apply oil

(ii) Fill the concrete in the molds in layers approximately 5cm thick

(iii) Compact each layer with not less than 35strokes per layer using a tamping rod (steel bar 16mm diameter and 60cm long, bullet pointed at lower end)

(iv) Level the top surface and smoothen it with a trowel

CURING

The test specimens are stored in moist air for 24hours and after this period the specimens are marked and removed from the molds and kept submerged in clear fresh water until taken out prior to test.

PRECAUTIONS

The water for curing should be tested every 7days and the temperature of water must be at 27+-2oC.

PROCEDURE

(I) Remove the specimen from water after specified curing time and wipe out excess water from the surface.

(II) Take the dimension of the specimen to the nearest 0.2m

(III) Clean the bearing surface of the testing machine

(IV) Place the specimen in the machine in such a manner that the load shall be applied to the opposite sides of the cube cast.

(V) Align the specimen centrally on the base plate of the machine.

(VI) Rotate the movable portion gently by hand so that it touches the top surface of the specimen.

(VII) Apply the load gradually without shock and continuously at the rate of 140kg/cm2/minute till the specimen fails

(VIII) Record the maximum load and note any unusual features in the type of failure.

NOTE

Minimum three specimens should be tested at each selected age. If strength of any specimen varies by more than 15 per cent of average strength, results of such specimen should be rejected. Average of there specimens gives the crushing strength of concrete. The strength requirements of concrete.

CALCULATIONS

Size of the cube =15cm x15cm x15cm

Area of the specimen (calculated from the mean size of the specimen )=225cm2

Characteristic compressive strength(f ck)at 7 days =

Expected maximum load =fck x area x f.s

Range to be selected is …………………..

Similar calculation should be done for 28 day compressive strength

Maximum load applied =……….tones = ………….N

Compressive strength = (Load in N/ Area in mm2)=……………N/mm2

REPORT

a) Identification mark

b) Date of test

c) Age of specimen

d) Curing conditions, including date of manufacture of specimen

f) Appearance of fractured faces of concrete and the type of fracture if they are unusual

RESULT

Average compressive strength of the concrete cube = ………….N/ mm2 (at 7 days)

Average compressive strength of the concrete cube =………. N/mm2 (at 28 days)

3. Slump test

Slump test is used to determine the workability of fresh concrete. Slump test as per IS: 1199 – 1959

is followed.The apparatus used for doing slump test are Slump cone and Tamping rod.

Procedure to determine workability of fresh concrete by slump test.

i) The internal surface of the mould is thoroughly cleaned and applied with a light coat of oil.

ii) The mould is placed on a smooth, horizontal, rigid and nonabsorbent surface.

iii) The mould is then filled in four layers with freshly mixed concrete, each approximately to one-

fourth of the height of the mould.

iv) Each layer is tamped 25 times by the rounded end of the tamping rod (strokes are distributed

evenly over the cross section).

v) After the top layer is rodded, the concrete is struck off the level with a trowel.

vi) The mould is removed from the concrete immediately by raising it slowly in the vertical direction.

vii) The difference in level between the height of the mould and that of the highest point of the

subsided concrete is measured.

viii) This difference in height in mm is the slump of the concrete.

Reporting of Results

The slump measured should be recorded in mm of subsidence of the specimen during the test. Any

slump specimen, which collapses or shears off laterally gives incorrect result and if this occurs, the

test should be repeated with another sample. If, in the repeat test also, the specimen shears, the

slump should be measured and the fact that the specimen sheared, should be recorded.

SILENT FEATURES AND SCOPE OF WORK

BRIDGE

The main RCC bridge comprises of :-

1. 8 spans of 122.948m with 18 segments on 61.478m on each side and a key segment in between on each span.

2. 2 spans of 105m on both ends with 30 segments.3. 2 spans of 150m with 22 segments on 75m on each side and a key

segment in between on each span.

Foundation type : Twin ‘D’ type well

Total No. of wells : 11 Nos.

Size of well : 16m x 10m

Depth of well : Average 57.00m

Size of well cap : 16m x 10m x 3m

Size of Pier cap : 12m x 8.8m x 4m

Size of Box Girder : 8075 x 8000/6500

Width of Main Bridge : 13.875m

Example segments in 150m span

There are two viaducts, at each ends of the bridge. The northern end viaduct comprises of 6 spans of 24m each (total length 144m). The southern end viaduct is having 4 spans of 27m each (total length 108m).

Foundation type : Cast in situ RCC vertical bored piles

Diameter of pile : 1200mm

Depth of pile : Average 24m

Substructure : RCC plate piers

Size : 7m x 1.35m

Height : 3.8m x 5m

Viaduct length : 252m

Width : 13.875m

FLYOVER IN JALUKBARI

A Grade separator, 6 lane wide is provided from Ch.1124+607.6 to Ch.1124+851.44. There is a provision for Reinforced earth wall & RCC bored piles with Counterfort RCC retaining walls at the approaches of the grade separators.

The crossing over Jalukbari rotary has been redesigned with a signal with a signal free crossing/intersection with a 3 nos. of loops, 3 nos of ramps, dumbell shape crossing and underpass.

Grade Separator LHS : (4x25)+(4x26.5)+38 = 238m

Grade separator RHS : (4x25)+(4x26.5)+38 = 238m

Loop 1 : (1x41.5)+(2x33.5)+(1x32)+(5x26.5)+(4x25)= 275m

Loop 2 : (3x25)= 75m

Loop 3 : (3x25)+(2x17.02)= 109.4m

Vehicular Underpass : 1x14= 14m

Approach : Reinforced earth wall/ Reinforced wall embankment

Ramps : 3 nos ( Ramp 1= 73m, Ramp 2= 702m, Ramp 3= 356m)

Layout of Jalukbari Project

Satellite view of Jalukbari Project

N

ROAD CONSTRUCTION

Flexible Pavement

1. Marcy filling- Sand upto Reduced Level

2. Embankment- 1. High Embankment- > 3m

2. Low Embankment- < 3m

3. Subgrade-

In transport engineering, subgrade is the native material underneath a constructed road, pavement or railway track. It is also called formation level.

The term can also refer to imported material that has been used to build an embankment.

It is done in 3 layers of 200m, 150mm and 150mm. Rolling is done after every layer.

4. Granular Subbase

Subbase is the layer of aggregate material laid on the subgrade, on which the base course layer is located. It may be omitted when there will be only foot traffic on the pavement, but it is necessary for surfaces used by vehicles.

Subbase is often the main load-bearing layer of the pavement. Its role is to spread the load evenly over the subgrade. The materials used may be either unbound granular, or cement-bound. The quality of subbase is very important for the useful life of the road.

It is done 2 layers each of 150mm. The materials used have diameter of 40mm- 80mm.

Macadams are all based on the principle of an aggregate coated with a binder, usually bitumen, hence "bituminous macadam". Asphalts are a mixture of asphaltic cement or mortar (often a bitumen with fine aggregates such as sands and grits) and some coarser aggregate, such as gravel or crushed rock.

The major difference between macadams, other than aggregate size and pen grade, is whether they are classed as Open Graded or Close Graded (aka Dense). Open graded macadam is composed of aggregate with very little fines and may be permeable. It is a popular choice for hand-laid basecourses as it remains workable for longer at lower temperatures. Dense macadam contains a significant proportion of fines (material of 3mm

or less). This means it is often classed as an impermeable material, and the tighter-looking finish make it a popular choice for wearing/surface courses.

5. Water Mix Macadam- When water acts as a binderIt is done in 2 layers of 115mm and of 110mm.

6. Dense Bituminous Macadam- When bitumen is used a binderPrime coat is applied after WMM then a 75mm of DBM then Tack coat then again a layer of DBM of 60mm.

7. Bituminous Concrete-

Asphalt concrete is acomposite material commonly used to surface roads, parking lots, and airports. It consists of mineral aggregate bound together with asphalt, laid in layers, and compacted. The process was refined and enhanced by Belgian inventor and U.S. immigrant Edward de Smedt. It is increasingly being used as the core of embankment dams.

The terms "asphalt (or asphaltic) concrete", "bituminous asphalt concrete", and "bituminous mixture" are typically used only in engineering and construction documents, which define concrete as any composite material composed of mineral aggregate adhered with a binder. The abbreviation "AC" is sometimes used for "asphalt concrete" but can also denote "asphalt content" or "asphalt cement", referring to the liquid asphalt portion of the composite material.

Embankment on flyover in Jalukbari

Subgrade on flyover in Jalukbari

WMM on flyover in Jalukbari

SOME PICTURES OF ONGOING PROJECT

Open foundation in Pier-6 of Loop 1

Closed foundation on Pier-4 of Loop -1

Counterfort retaining wall on Main Flyover in Jalukbari

Pier-1(under cons.), Pier-2 and Pier-3 of Loop-1

Loop-2

Ongoing work on slab between P-1 and P-2 in Loop-1

View of main flyover from Loop-1

To be built Loop-3

Total Station

Shock absorber between span and Pier-17 in Main Bridge

Construction of New Bridge beside Saraighat Bridge

CONCLUSION

As Gammon India is the largest construction company in India and after getting the contract for the construction of the bridge beside the famous Saraighat Bridge and the Signal Free Crossing in Jalukbari the work seems steady and it is expected that the work will be complete as per the due date.

As I have vocational training in the big project, I have learnt a lot of new things. I have learnt a lot about the Quality Control which is the first and foremost thing to do before construction. I have learnt about testing done on soil, aggregate, cement, concrete, etc. I have learnt about the minor mistakes in measurement can cause heavy losses in lakhs. I have also learnt about being persistent. I have also saw how the construction is done and challenges faced on the field which can never be understood in a classroom.

So, I thank Gammon India for giving me such a great opportunity to do this vocational training which taught me a lot of new things.

BIBLIOGRAPHY

www.wikipedia.org

www.google.com

www.civilengineering.com

http://nptel.ac.in/

http://www.tifr.res.in/

http://www.pavingexpert.com/