The Bogibeel rail / road bridge is being built across the River Brahmaputra in the Dibrugarh district, in the state of Assam in north-east India. The 4.94km bridge is one of the longest river bridges in India.

The rail-road bridge is being undertaken by the Northeast Frontier Railway, which is a part of the Indian Railways. The work on the project began in 2002 and was expected to be completed in seven years. But it has experienced time and cost overruns.

It is now scheduled to be completed by the end of 2015. The originally estimated cost of INR16.7bn (approximately $312m) shot up to INR33.78bn ($630m) by 2011. Until 2011, INR20.30bn ($378m) had been spent on the project.

Bogibeel Bridge location

The bridge will be located 17km downstream of the town of Dibrugarh. It will connect Dibrugarh in the south to Lakhimpur in the north. The River Brahmaputra runs to the north of Dibrugarh and is very wide, spreading 10km.

The rail-road bridge is the fourth being built on the river, the others being Pandu Saraighat, Kolia-Bjumuraguri and Naranarayan Setu at Jogighopa – all of them in Assam. The Bogibeel Bridge is the longest structure being built on the River Brahmaputra.

Dibrugarh district rail-road bridge project

"The Bogibeel rail / road bridge is being built across the River Brahmaputra in Dibrugarh, in the state of Assam in northeast India."

The Bogibeel rail-road bridge is a double-deck bridge with a three-lane road passing above a two-line railway track. The upper deck carrying the roadway will be 10.5m above the railway line on the lower deck.

The road will be connected to the National Highway 37 (NH37) on the south bank of the Brahmaputra and to the NH52 on the north bank.

The project includes construction of 29.45km of road (including the bridge) and a rail link of 74km. The north dyke will be raised and strengthened for 9km upstream and the south dyke for 7km downstream.

The road bridge will include a northern bank approach of 8.65km and a southern bank approach of 8km. Assam Public Works Department is responsible for the construction. Work is in progress on both the approaches.

River Brahmaputra bridge design and construction

The Bogibeel Bridge is a welded-steel-truss-and-reinforced-concrete structure. It spans 125m and has strong box-type built-in sections.

The bridge is supported on well foundations and 42 piers. The three-lane road will have footpaths on either side. The project got the approval of the federal Cabinet Committee on Economic Affairs (CCEA) in September 1997 and construction began in April 2002.

Major earthworks and strengthening of the north and south dykes was completed by June 2011. As of the end of 2011, 13 well foundations on the south bank and 11 well foundations on the north bank are in progress for the main bridge.

About INR30.87bn ($576m) worth of works are being executed by the Northeast Frontier Railway while INR2.91bn ($54m) works are being undertaken by the Public Works Department of Assam.

The superstructure of the bridge is scheduled to be completed in 2013. The project requires about 505ha of land, which has been acquired across 19 villages.

Contractors involved in the Bogibeel Rail-Road Bridge in Indian state of Assam

The state-owned consultancy and project management enterprise Rites (Rail India Technical and Engineering Services) has undertaken the pre-construction studies and detailed design of the rail-road bridge. Top-Notch Engineers was involved in the design and drawings of the bridge.

"The rail-road bridge is being undertaken by the Northeast Frontier Railway, which is a part of the Indian Railways."

The well foundations and substructure of the bridge are being constructed by Gammon India under an INR3.44bn ($64.62m) contract. Assam-based Bharatia Infra Projects has supplied aggregates for the bridge under an INR540m ($10m) sub-contract from Gammon India.

Bharatia Infra has constructed the guide bunds and approach embankments on the south bank of the bridge. It has also won an INR700m ($13m) contract to construct the south bank road viaduct.

A joint venture of Hindustan Construction Company (HCC), Germany-based DSD Brouckenbau and VNR Infrastructures will build the superstructure of the bridge under an INR9.87bn ($185m) contract awarded in November 2011.

The superstructure is planned to be completed in 48 months. HCC holds a 51% stake in the JV while DSD owns 20% and VNR 29%. One of the other important projects of HCC in India is the Bandra Worli Sea Link in Mumbai.