18 October 2019

Table of Contents for Project Focus





Project Focus

Bridging excellence

 

The Bogibeel rail-cum-road bridge being undertaken by the Northeast Frontier Railway is a first-of-its-kind mega project which will raise the infrastructure profile of India’s north-eastern states.

 

Being constructed over the Brahmaputra, 17 km downstream of Dibrugarh in Assam is the Bogibeel rail-cum-road bridge. The project being constructed for Double Line BG Track and three lane road on completion will be the longest rail-cum-road bridge in India having a total length of 4.94 km. The Bogibeel Rail Cum Road Bridge Project was sanctioned in 1997-98 and the foundation stone was laid on 22nd April, 2002. Construction work however picked up pace after it acquired National Project status in 2007. The project being executed by the Northeast Frontier Railways (NFR) is expected to be fully commissioned by June 2017.

 

On completion the bridge is expected to facilitate improved connectivity between the north and south banks of the river Brahmaputra in the eastern region of Assam and Arunachal Pradesh. It will emerge as the lifeline of the country’s north-eastern regions and strengthen the region’s national security.

 

 

SALIENT FEATURES

 

The project involves a main bridge, guide bunds on the north and south banks, dykes , a road network of 30 km, a rail network of 74 km and 6 new stations including New Dibrugarh. The main bridge foundation has 42 double D-shaped well of 16.2m x 10.5m dimension. The steining thickness of the well is 3.0 m whereas diaphragm is 2.5m thick. The depth of the foundation is 58.60 m except abutment and shore well where depths are 42 m and 68.75 m. The well cap is constructed at a thickness of 2.2 m. The substructure of the bridge consists of twin circular hollow piers of outer diameter 5.30 m and inner diameter of 3.30 m. The pier cap is 1.2 m thick. The soil strata is sandy silt in general for full depth. Gammon India Ltd is executing the construction of sub-structure involving 42 wells. Of the total 42 well foundation works 36 are already complete and the remaining will be fully completed within this year.

 

Super-structure of the Bogibeel Bridge is a Composite Welded Double Warren Truss (1 x 32.75m + 39 x 125m + 1 x 32.75 m) with 2 BG tracks on the lower deck and 3 lane road on the top deck. The girder is having steel flooring system for railway and Welded Steel Truss Composite with concrete deck for road on top. Such a girder type for a mega structure is the first-of-its-kind being constructed in India.

 

Work on the project’s super-structure is being executed by HCC-DSD-VNR Consortium. Designer support is being provided by RITES and Ramboll, Denmark, for resolving the different technical issues involved in the fabrication of the Girders. Steel Fabrication of the super-structure is being done as per Euro Standards and accordingly Segmental Quality Plan (SQP) has been approved for fabrication works of steel components. The fabrication of components is being done in separate fabrication shops at site. These fabrications shops have all weather facility with proper ventilation and lighting arrangements having concrete flooring. Each shop comprises of stacking area, cutting area, drilling area, fit up area, welding and inspection areas. The job related to grit blasting and painting is being done in the fabrication yard itself. Separate platforms are provided for the joints and box sections for fabrication of components using jigs and fixtures.

 

The bridge girders are being installed through incremental launching. The superstructure is divided in 4 launching units, each unit consisting of 10 spans of 125 m (4th unit of only 9 spans) with a launching nose of 35 m in front and rear. The shore spans of 32.75 m will be erected by crane after the launching process is finished. For Launching the 10 girder train, 2 jacks of 1000 MT capacity each will be installed at specified Piers. Girder spans will be disconnected after completion of launching and lowered on to the bearings in the final position.
 

 

PRESENT STATUS

 

An important milestone of this immensely important project specially from a strategic consideration was achieved when on 25th July 2015, the 1st train of 10 girders commenced its journey from the South Bank of Bogibeel Bridge towards the North bank across the river Brahmaputra. This is the first train of girders being pulled across the river. There will similarly be three more trains consisting of 10 and 9 girders respectively. Each girder is all welded steel construction of length 125 m. The work of fabrication, assembly and erection of the 2nd train of 10 girders has already started. The project is progressing as per schedule with 2100 workers, welders and engineers of HCC-DHD-VNR consortium. The launching of all 39 spans is likely to be completed by March 2017.

 

The project executioner HCC claims that a total of 70,000 MT of steel will be used for completing the superstructure, which will be equivalent to 10 Eiffel Towers. Moroever, being a fully-welded bridge, the total length of welding to be carried out is about 12,800 km, which is equivalent to circling around the moon 1.5 times. In addition, construction on the South Bank Guide Bund and North Bank Guide Bund is also now fully complete.

 

 

RAIL-ROAD CONNECTIVITY

 

The rail link across the bridge will connect two existing railway networks running at south bank and north bank of the river Brahmaputra. It starts from Chaulkhowa station and Moranhat station at south bank and joins in between Sisibargaon station and Siripani station of Rangiya-Murkongselek section at North Bank. The present railway network at north bank side is Meter Gauge which is under conversion into Broad Gauge. Apart from these, a station, New Dibrugarh, is being planned for the construction at Boiragimoth Kachari village in Dibrugarh. The station is expected to be the biggest in the region. A double line track of 16.65 km from Dhamalgaon station (South bank) to Tangani station (North bank) will be also laid over the Bogibeel Bridge.

 

Apart from these the Public Works Department -PWD (NH), Government of Assam has completed the common embankment for the NH portion on both sides of the bank. The length of NH portion to be constructed by PWD (NH) is 16.71 km(excluding NH portion by Railway). Agencies for north bank NH approach as well as for south bank NH approach have been deployed by PWD/NH and the work is presently in progress. National Highway of 29.446 km will connect NH-37 at south bank and NH-52 at north bank of the river Brahmaputra. Under the project NFR will be also constructing road viaducts of 832.422 m length connecting Bogibeel Bridge with National Highway.

 

 

PROJECT COST

 

The project though was originally inaugurated in 2009 had to face severe delays due to natural, economic and political uncertainties. The project recently faced a cost escalation of about Rs.300 crore, wherein the HCC led-consortium was hit due to the expansion work and recurrent project delays. Though the company received the contract for Rs.987 crore in 2011 for the construction of 36 spans or girders, the design were modified in the latter period and was increased to 41 spans. This has now raised the entire superstructure’s cost to about Rs.1,300 crore. The project presently is estimated to be worth Rs.4996.19 crore.

 

 

KEY CHALLENGES

 

The challenging geographic terrain and the crunching cost over-runs has been the major causes leading to delay in the much awaited infrastructure project. The construction of guide bunds has been the most challenging task of this project as it was to be completed up to the safe level in all respects during the very short working period (four to five months) after completing all pre-requisite river training works. The width of river at the alignment location of the bridge was approximately 10.30 km.

 

A crucial challenge that hit the project was the early flood in the river Brahmaputra which restricted the construction work season to a very short period of about five months. This demanded a huge mobilisation of equipment and the concerns were addressed by constructing Approach Embankments. The construction involved setting up of ‘approach embankments’ inside the dyke up to the abutments of the Bogibeel Bridge before placing the Guide Bunds. The Approach Embankment consisted of a formation for double line track, 7.5m NH and 5m wide Service Road. At the North Bank, the length of Approach Embankment is 3.125 km and at the South Bank it is 2.25 km.

 

Another major challenge was the transportation of concrete across river channels of 600m to 900m width from both the banks. The challenge was addressed by laying a pipeline to pump the concrete over buoys with multiple concrete

 

 

MEGA PROJECT DETAILS

  • Name of project:  Bogibeel Rail-cum-road Bridge
  • Location:  Dibrugarh, Assam
  • Total project cost: Approximately Rs.5000 crore
  • Crosses: River Brahmaputra
  • Total Length: 4.94 km
  • Design: Truss bridge
  • Material: Steel, Concrete
  • Authority: Northeast Frontier Railways
  • Private Entities Involved in Construction: HCC-led consortium (Hindustan Construction Company, DSD Brouckenbau, VNR Infrastructure), Gammon India
  • Date of Commencement: 22 April 2002
  • Estimated Project Completion Timeline: 2017



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