BOGIBEEL BRIDGE

BOGIBEEL BRIDGE

1. BOGIBEEL BRIDGE Submitted To Submitted By D r . Kanish Kapoor Shivam saini 18202123 (Assam)

2. INTRODUCTION Bogibeel bridge is a combined road and rail bridge over the Brahmaputra  river in the  north eastern indian  state of  Assam   . Bogibeel river bridge is the  longest rail cum road bridge   measuring 4.94 kilometres over the Brahmaputra river .  It is Asia’s 2nd longest rail-cum-road bridge and has a serviceable period of around 120 years . The bridge has a double rail line on the lower deck and a 3 lane road on the upper deck.

3. LOCATION AND CONNECTIVITY The Bogibeel bridge , situated 17 km downstream of   Dibrugarh  and  Dhemaji districts, spans the Brahmaputra river and will connect the town of Dibrugarh in the south to  Dhemaji  to the river's north. The bridge is located just over 20 km away from the Assam- Arunachal Pradesh  border and acts as an alternative to the Kolia Bhomora Setu , Tezpur in providing connectivity to nearly five million people residing in Upper Assam and Arunachal Pradesh. Road connectivity through national highway 15. Rail connectivity through North Eastern frontier Railway.

4. DESCRIPTION Bogibeel Main Bridge (With Double line )- Span – 2*32.75 m + 39 * 125 m (4.94 km) Sub -Structure – Double D well foundation Super -Structure – Composite welded steel truss girders Guide bunds – north (2792 m ) and south (2043m ) long – to constrict the river width of 10.3 km to 4.94 km Raising and S trengthing of north and south dykes for 9 km on upstream and 7 km on downstream. Rail link on south /north bank -74 km NH- 15 –road link 29.455 km on north and south bank including 4.94 km on north and south bank including 4.94 on main bridge .

5. SUB-STRUCTURE Well Foundation: Well foundations are one of the types of deep foundations that provide a solid and massive foundation typically for bridges and heavy structures. Well foundations are also useful for transmission line towers, where uplift loads are large.  Well foundations had their origin in India and have been used for hundreds of years for providing deep founda­tions for important buildings and bridges. Many Mughal monuments, including the famous Taj Mahal and several bridges, were supported on well foundations .  Well foundations actually belong to one of the types of caissons.

6. CAISSON AND ITS TYPES Caissons are box type foundations used to support bridges and other heavy structures and sunk into the ground under self-weight with additional weights applied at the top . Three types of caissons are commonly used, which are as follows: Open caissons. Box caissons. Pneumatic caissons .

7.   Open Caissons : Caissons in which the top and bottom of the caisson are open during construction.   Open caisson may be circular, rectangular or oblong in plan.  It has a cutting edge at the bottom.

8. Box Caissons: Box caissons are open at the top, but closed at the bottom. It is first cast on land and then towed to the site, where it is sunk onto a previously leveled foundation base. Box caissons are also called floating caissons, and are used where loads are not very heavy and a bearing stratum is available at shallow depth.

9. Pneumatic Caissons: In pneumatic caissons, the internal air pressure of the closed chamber is kept high to prevent water from entering the chamber  . The working chamber is thus kept dry to facilitate skilled persons to work in the chamber. Air locks are provided at the top.  The working chamber is filled with concrete after the final depth is reached and sinking of the caisson is completed.

10. SHAPES OF WELL FOUNDATION Circular. Twin circular. Square/Rectangular. Double D. Hexagonal/Octagonal.

11. SUPER STRUCTURE For the construction of super structure , ( Hindustan construction company )HCC has set-up huge facilities on the left bank of the river, and had three sequences of Fabrication, Assembly and Launching . Fabrication:  The Fabrication Shops of 2000 MT per month capacity were set-up with two parallel Bays. The team had assembled customized platforms in-house to fabricate and fit various joints employing Gas Metal Arc Welding (GMAW).  Assembly:  Thereafter, these fabricated sections are moved to the assembly shop where they are installed on their designated beds. They are guided to their correct positions through jacking and welded by GMAW process. 

12. Launch : 1000-ton hydraulic jacks and strand jacks linked with the substructures were used for moving the steel truss over the pillars.  Two sets of steel cable strands were anchored to the end cross beams of the Truss and hauled by hydraulic jacks .  The Truss slides over the Launching Bearing with the help of Sliding Plates, which were inserted at one end and taken out at the other, thereby moving the Truss towards its desired position.   In order to limit the required launching forces, the superstructure was pulled in 4 launching segments of 10 spans each.   The superstructure was pulled over the pillars just like a train of ten spans. With each span weighing 1700 MT, the pulling force required was equivalent to pulling 26 airbus A380 with maximum take-off weight over 650 tons, put together without any wheels.

13. Finally, the launching bearings were replaced by final bearings. The tracks were laid, and the road was constructed adapting RCC construction. After fulfilling the electrical and other ancillary requirements, the assignment was completed.

14. MORE FACTS OF BOGIBEEL The project boasts of benefits such as strategic and speedier access for defence forces to the Indo-China border, which means faster movement of troops and heavy weaponry . Its biggest benefit is the travel time that it will save: as of now, a train journey from Arunachal Pradesh to Assam's Dibrugarh requires a 500 km detour via Guwahati. Now, the journey is reduced to less than 100 km. Also, the train journey between Delhi and Dibrugarh has reduced by 3 hours . It is hailed as an engineering marvel of the country as construction of such a mega-bridge in a seismically sensitive zone was a herculean task for the engineers. About 30 lakh bags of cement, 19,250 mt 2 reinforcement steel, and 2,800 mt 2 structural steel were used. Has earned the distinction of being Asia's second largest bridge with three-lane roads on top and a double rail line underneath. Constructed at a cost of ₹5,920 crores. Bogibeel is India's first and only fully welded bridge construction. It is also for the first time that European codes and welding standards were adhered to in the construction of a bridge in India.

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