PROJECT REPORT

ON

Rehabilitation of Major Bridge No. 37 on Kharagoda river between Patdi and Kharagoda stations at VG-KOD BG Section on Ahmedabad Division of Western Railway

Course : Management Development Programme –03/09

Course Director: Shri A K Agarwal, SPME

Project Guide:Shri R S Rajpurohit, SPCE

Participants

Shri S.D.Pandey , Exe.Engineer./Con./Ahmedabad/WR

Shri S.S.Bhattacharya, Dy.CME/Safety/NWR/JP

Shri U.K.Singh, Dy.CME/Project/Jamalpur/ER

Shri V.H.M.Patro, Dy.CEE/Con/BBS/ECoR

Shri Ram Autar, Dy.FA&CAO/CORE/ALD

ACKNOWLEDGEMENT

We the group of members of this project extend our sincere thanks to our Course Director Shri A K Agarwal, Sr.Prof. Mech. Engg. for his valuable suggestions and content inspiration for the completion of this project.

We are also extremely grateful to Shri R S Rajpurohit, Sr.Prof. Civil Engg. our project guide for his useful and valuable guidance and suggestions throughout the project.

We are also thankful to Director General Sir and other faculty members of this institution for providing a pleasant academic atmosphere by providing greater insite into Railway working and management throughout our stay in Railway Staff College.

We also express thanks to all other ministerial and supporting staff of this institution for comfortable stay during our course.

All the Project Members

INDEX

Sr.No. / Content / Page No.
1 / Acknowledgement / 2
2 / Synopsis / 4
3 / Introduction / 5-6
4 / Case study ,Salientfeature,Objective and Rationale for study / 7-8
5 / Detailed methodology / 9-10
6 / Expected contribution from study,list of activities and input data / 11-12
7 / Execution of work / 13-16
8 / Data required for bar chart / 17-18
9 / Pile load test / 19-22
10 / Merits of RCC Piles over Steel Screw Piles / 23
11 / Benefits,Suggestions and Conclusion / 24
12 / Cross sectional drawing of bridge No.37 / 25
SYNOPSIS

Railway track network is spread over 62000 kms in all length and width around the country. Railway track passes over a large number of rivers, lakes, canals and other waterways. The bridges are provided over these waterways and rivers to pass over the track. Therefore bridges are of very vital permanent way structures of Indian Railways. Indian Railways has more than 6000 numbers of (major and minor ) bridges. Out of them considerable number of bridges were constructed before independence on Indian railways. These bridges have become very old and lost sufficient strength and they required either replacement by providing new bridges or rehabilitation as necessary. In some cases replacement of bridges is very costly and time consuming hence in case were rehabilitation can serve the purpose, the same is being done in less time and economically.

In the present case study the details of rehabilitation of an old age steel screw pile bridge, which had developed transverse cracks in the piles. This bridge no. 37 is between the Viramgam and Kharagoda stations of BG section in Ahmedabad Division of Western Railway. This bridge is situated on Kharagoda river which is perennial river. This section has no passenger traffic and freight traffic only is being operated in this section and also traffic density is low. Hence it is decided to rehabilitate the steel piles by encasing them by providing new “H” shape RCC friction piles. A significant phenomenon of this encased RCC piles structure is that it will off load the old cracked steel pipe for taking the load Without dismantling them.

The cost to complete this project has come to Rs 3.16 cr. whereas the construction of new bridge in lieu of this bridge would have cost approximately Rs. 5.25 cr. Hence a net saving of Rs 2 cr. approximately has been achieved.

INTRODUCTION

Name of work : Rehabilitation of major bridge no 37 on KHARAGODA river between PATDI- KHARAGODA stations at VG-KOD Section in ADI division of Western Railway.

In his speech Honorable Ex Railway Minister shri NitishKumar while introducing the Railway Budget in Parliament in the year2002-03 0n date 26.02.2002 told that tragic accident on the kadalundi bridge in June2001 has brought the safety a matter of serious concern. The Railway Safety Review Committee headed by justice sri H.R.Khanna in his report has recommended that over aged safety related assets of Indian Railways needed to be replaced or renewed speedly. Accordingly special railway safety fund of Rs 17000 Cr . has been setup for clearing the back log of replacement of over aged assets over the next six years.

The safety related works expected to be executed through this fund included renewal of nearly 17000Km of track, rebuilding of over 3000 Nos. bridges ,replacement of signaling gears at 950 stations,Replacement of rolling stocks and investment in safety enhancement aids.

Brief History :: Rehabilitation of major bridge no 37 on KHARAGODA river is part of SRSFwork explained above. Previously this bridge was built up on steel screw Piles during British ruling on VG-KOD BG Section in ADI Div. of WesternRly. During inspection of the Bridge the cracks were noted by open line hence the speed restriction of 20Kmph was imposed on this bridge and work was proposed in works programme for rehabilitation during the year 2002-03. The same was sanctioned in SRSF works during the year 2002-03 and appeared at item no.294 of the green book. The estimated cost of this work was Rs2.88 cr., which was, revised toRs 3.16 cr. In ADI division under SRSF 4 number bridges such as bridge number 18 and 37 on VG-KOD sectionand bridge no. 15 and 55 on Ahmedabad Himmatnagar section were sanctioned. This bridge has 5 no.of spans of 18.30 m. length each with fish valley type steel plate girder. 3 nos.of spans which were not serviceable were procured from BCT division and 2 no. Of girders were used from existing bridges after renovation in engineering workshop Sabarmati.

The steel screw piles were encased by providing “H” shape RCC piles, pile cap, pier, and pier cap and bed blocks. But the steel screw piles were kept free from transfer of super imposed loads. The load was purely transfer to new constructed structure. This is Perennial River having depth of water from 5 to 6 mtr. in summer season. The whole work of rebuilding of this bridges was carried out under train movement and speed restriction of 20 Kmph for the entire period of work. There is a big salt quarry at Kharagoda village near by to this river from where a lot of freight traffic of salt transportation is carried out on this line. If new bridge at diverted alignment would have been constructed it would involve larger cost of Rs 5 Cr. Thus there was a saving of Rs 2 Cr approximately.

4.A CASE STUDY:

There have the various rail works on western Railway, were laid more than hundred years ago as such the bridges on such section, to cross the water channel on nos. of places on alignment were constructed along with lying of track. Some of these bridges have stood for hundred years with routine maintenance and repairs, however as per safety principle they are considered to have completed their lives and it is prominent to replace them by anew structure.

Failure of such over aged structure may occur at any time, which may cause a great loss of man and money. Now as there reconstruction/improvement is over due

4.B SALIENT FEATURE:

This case study pertain to bridge no.37 on Viramgam-Kargodha section of Ahemdabad division of western Railway (Saurastra region).

Bombay Baroda BBCI Railways laid the Railway track in 1893. The bridge is of five spans bridge having for piers, two abutments. Each span is of18.30 mt .Each pier constitute two cast iron screw piles of 0.90mt diameter filled with line concrete.

At the top of piers on cross girder is provided which support the open web girder over which the track is laid. In order to meet the expense for such a renovation/rebuilding of such century old bridges, Indian Railways have created SRSF fund

4.C THE OBJECT OF STUDY:

The object of the study is as follows:

1.0 Necessity for Rebuilding of bridges.

2.0 Method to be adopted for rebuilding

3.0 Execution methodology

4.D RATIONALE FOR STUDY:

Indian Railway is basic mode of transportation for common people and goods transport especially for long distance. Its track, bridges, signaling system, structures are the backbone of this system. Due to increase in traffic, increase in axle load,introduction of higher speed old aged of bridges (over aged) .There are the factors initiating the need rebuild /renovate such bridges .

DETAILED METHODOLOGY TO BE USED FOR CARRYING OUT STUDY:

For detailed methodology bridge is divided in two parts:

  • Sub structure
  • Super Structure

I)Sub Structure:

Sub Structure consists of the following.

  • Foundation
  • Abutment and Pier above the bed level i.e. top of foundation to

top of pier.

  • Bed block and bearing arrangement over the bed block.

Foundation: Type of foundation – After the soil exploration

survey and bore log strata of such soil with SPT value, keeping in

mind the modern MBG (Modified Broad Gauge Loading), 1.2

meter dia cast in situ RCC bored piles have been provided.

Accordingly necessary pile cap as per the design has been

provided.

Height of bridge: Height of the bridges are decided on the basis of water way cancellation, Highest flood level which was available on metrological department & sectional PWI’s Bridge Register with the provision of necessary clearance as per IRS Bridge code.

Then the pier cap has been provided over which precast bed block placed. Over the bed block proper bearing has been placed so that the center to center of girder & necessary gap between two girders over the pier matched as per the drawings.

I)Super Structure:

Old girders were of early steel girder which were replaced by the fish balleyed plate girder fabricated at Engineering workshop of western Railway at Sabarmati, Ahmedabad.

For replacing the girder full traffic block was taken for four to six hours per span. During the traffic block existing track was removed and old steel girder was also removed by crane. Thereafter new steel girder was launched over the bearing and subsequently track was laid.

THE EXPECTED CONTRIBUTION FROM THE STUDY:

The Study of rebuilding of old Railway Bridges may contribute the following:

  • Method of rebuilding.
  • Problems likely to face and their solution during the executions.
  • To know the reasons responsible for rebuilding.
  • Cost of rebuilding.

LIST OF ACTIVITIES TO BE CARRIED OUT TO COMPLETE THE PROJECT:

List of major activities are as follows:

  • Data collection and drawing preparations.
  • Borelog data of sub soil and geological data.
  • Hydrological data like water way, HFL, Discharge, Catchment

area.

  • Design of sub structure and super structure.
  • Physical execution of work.
  • Boring of piles, its casting and pile cap.
  • Construction of pier and abutment.
  • Placing of bearing.
  • Removing of old girder/ providing new girder.
  • Linking of track.
  • Protection work.

PLACES/ LABS/ EQUIPMENTS AND TOOLS REQUIRED AND PLANNING OF ARRANGEMENT:

  • Bridge No. 37 in Viramgam – Kharaghoda section of Ahmedabad Division of Western Railway.
  • Soil Exploration and site laboratory by KCT Consultancy, Ahmedabad.
  • Pile boring machine.

INPUT DATA/ STRUCTURE/ QUESTIONAIRE:

Data required for drawing and design purpose.

  • Geological Data i.e. bore log.
  • Hydrological Data – HFL, Position of water table, catchment area probable velocity during flood, water way calculation. Clearance distance between HFL to Soffit of the girder.
  • Pile Load test – Static test.
  • IRS Bridge rule – 1964.
  • Staffing: – Assessment of staff for skilled and unskilled category and according arrangement has been done.
  • Engineer – One No.
  • Supervisor – One No.
  • Skilled labour for reinforcement and shuttering – 15 Nos.
  • Unskilled labour – 35 Nos.
  • Machinery and T&P required:
  • One JCB with tractor .
  • Boring rig – 4 to 5 nos.
  • Tanker – 2 Nos.
  • Mixer – 3 Nos.
  • Vibrator – 3 Nos.
  • Water Pumps.
  • Electric connection / generators.
  • Material:
  • Cement 53 grade.
  • Sand as per 15383, Zone –II.
  • Steel conforming to IS.
  • Structural steel conforming to IS.

EXECUTION OF WORK:

  • Layout of pile – With the help of base line method lay out of pile has been done. Exact location of pile is very important.
  • Boring of pile – Boring of pile has been done with percussion method by using the winch machine and drilling mud method with pile rig machine. Proper centering of tripod/ machine has been done first on the center already marked on ground by lay out. Then during boring verticality of pile is utmost important. Deviation limit is 75 mm as per IS code. Bentonite solution has been used during the boring of pile to avoid the collapse of pile.
  • Placement of Reinforcement – Reinforcement has been provided as per RCC detailed drawing with proper lap ( not less than 45 x d) and staggering of joints. Use of proper cover block (50 mm) and welding of bars has ben done. Helical ring must be at proper spacing. This operation took nearly six hours. 32 mm TMT steel conforming to IS has been used.
  • Placing of Tremie pipe – After the reinforcement placing tremie pipe dia of 25 cm having length 0.90 to 1.20mts have been placed one by one by lowering them with air tight joint upto 30 to 50 cm above the bore bottom level.
  • Flushing of Piles – Now the flushing of pile bore has been done with the bentonite solution of density with the help of pump. By sending the solution through pipe sedimented mud agitated and lift up came out of pile. This operation took 35 to 60 minutes.
  • Concreting for piles – After completion of flushing, funnel has been tightened to tremie and first of all its holes were plugged. Then concrete has been poured for 8 to 10 loads on the funnel. Now the plugging cover has been removed so that full 8 to 10 loads which were filled in funnel goes down through pipe to bottom of pile bore and replaces the water in pipe and plug the bottom of tremie pipe with green loose concrete. Further concrete is directly poured to pipe to the bottom and replaces the mud up and flow out side the bore hole. Concrete poured till over flow of concrete minimum 60cm above the cutoff level.
  • Grade of Concrete – M- 35.
  • Quantity of concrete to pour as required
  • Time of completion – 15 hours
  • Casing of pile cap – All the piles were cleared up to cut off level by removing the concrete above the cutoff level. 10 cm thick lean 1:3:6 has been provided first all around the size of pile cap then reinforcement of TMT bars as per design schedule have been placed. After the placement of steel shuttering plates then concrete has been poured up to proposed top of foundation as per drawing. Grade of concrete – M-35.
  • Construction of Abutment and Piers above Top of pile cap – After the casting of pile cap, abutments and piers have been constructed lift wise casting is done with concrete of M-35. Normally 3 to 4 lifts have been required to reach the top of abutment/ piers. Pier cap was casted at the top of pier over which bed block placed taking into account the center to center of girders.
  • Marking of bearing – Exact location of bearing has been marked on pedestal keeping in mind that center to center of bearing match to the center to center of girder and gaps between the two girders not exceeding 100 mm on every pier or between the dirt wall and abutment girder.

WORK CARRIED OUT UNDER TRAFFIC BLOCK:

  • Advance preparation of collection of required material, man power and crane. Then traffic block permission was obtained from the Railway control through Station Master of the nearest station and following works were done.
  • Removal of track – First the main rails and guard rails were removed following the removal of bearing plate and sleepers with hook bolts.
  • Removal of girder – Existing steel girder was removed by lifting it by crane. On the opposite side where the new girder was resting. A standby crane arrangement is a must for this activity.
  • Placement of bearing – Bearing was placed at the exact location marked already. Wooden block of the same height were kept all around the exactly placed bearing so that the bearing is not disturbed during the launching of new girder.
  • Launching of new Fish Ballied Steel Girder – New steel girder fabricated at Engineering workshop at Sabarmati were lifted by two cranes simultaneously and placed over the bearing very gently. If alignment and gap of girder exact, then the wooden block which were kept to protect the bearing from disturbance during the launching are removed.
  • Linking of track –Again the position, alignment of girder checked. If it is okay then sleepers were laid over it at proper spacings which were tightened by hook bolts and iron strips made of flats. Over the sleeper on the notch the bearing plates were placed and tightened by plate screw. Over which rails were placed and tightened with two way keys.
  • Now traffic block cancelled and train allowed to pass through with caution order.

OTHER RELATED WORK: