Vidyasagar Setu, also known as the second Hooghly Bridge, is a toll bridge over the Hooghly River in West Bengal, India, connecting the cities of Kolkata and Howrah.
Opened in 1992, with a total length of 823 metres (2,700 ft), the Vidyasagar Setu is India's first and longest cable-stayed bridge. It was the second bridge built over the Hooghly River; the first, the Howrah Bridge (also known as Rabindra Setu) 3.7 kilometres (2.3 mi) to the north, was completed in 1943. Named after educational reformer Pandit Ishwar Chandra Vidyasagar, it cost ₹3.88 billion to build. The project was a joint effort of the public and private sectors under the control of the Hooghly River Bridge Commissioners (HRBC).
The importance of the bridge has increased manifold since 2013, as the West Bengal State Secretariat shifted its office to Nabanna, located next to the bridge, next to Howrah.
History
After India gained independence in August 1947, population and commercial activity increased rapidly. The only connection across the Hooghly River, the Howrah Bridge between Howrah and Kolkata, faced heavy traffic congestion with over 85,000 vehicles passing through it daily. This necessitated the planning of a new bridge over the river to connect it to the major cities of Mumbai, Delhi and Chennai via the national highways located near the bridge.
The foundation stone of the bridge was laid by Indira Gandhi on 20 May 1972. The bridge took 20 years to complete and cost ₹3.88 billion (equivalent to ₹25 billion or US$320 million in 2020), but there was no construction activity during those seven years. The bridge is named after the 19th-century Bengali educational reformer Pandit Ishwar Chandra Vidyasagar. Work on the cable-stayed bridge began on 3 July 1979, with the construction of the Well Curb on the Kolkata bank.
There are three other bridges over the Hooghly River connecting Kolkata with Howrah district: Vivekananda Bridge (a road-cum-rail bridge) built in 1930 - the first to be commissioned, and which had become old and in need of repair; Howrah Bridge, a cantilever bridge commissioned in 1943, now named Rabindra Setu (in honour of Nobel laureate Rabindranath Tagore since 1965); and Nivedita Setu (named after Sister Nivedita), also known as the second Vivekananda Setu, which is 50 metres (160 feet) downstream of the old Vivekananda Bridge and was commissioned on 4 June 2007. The Kona Expressway and Vidyasagar Setu have experienced a significant increase in traffic volume over the years.
More than 100,000 vehicles travel along the expressway to reach Kolkata via Vidyasagar Setu.
Construction
The bridge was designed by Schlaich Burgerman & Partners and checked by Freeman Fox & Partners and Bharat Bharti Udyog Nigam Limited. The construction was carried out by a consortium of “The Braithwaite Barn & Jessop Construction Company Limited” (BBJ). The Hooghly River Bridge Commission (HRBC) was responsible for commissioning the bridge. Construction work began on 3 July 1979, and the bridge was commissioned by the Hooghly River Bridge Commission on 10 October 1992.
Architectural features
Vidyasagar Setu is a cable-stayed bridge, with a system of 121 cables, constructed using a 127.62 m (418.7 feet) high steel arch. With a total length of 823 m (2,700 feet), Vidyasagar Setu is the longest cable-stayed bridge in India (the 3rd longest Narmada Bridge in Gujarat is an additional bridge).
The deck is made of composite steel-reinforced concrete with two carriageways. The bridge has a total width of 35 m (115 feet), 3 lanes in each direction, and 1.2-m (3 feet 11 inch)-wide footpaths on each side. The deck above the main span is 457.20 m (1,500.0 feet) long. The two side spans are supported by parallel cable cables and are 182.88 m (600.0 feet) long. Vidyasagar Setu is a toll bridge. It has a capacity to handle over 85,000 vehicles in a day.
The design of the bridge is slightly different from other bridges of live load composite construction. The difference is the concept of dead load design adopted for this bridge and the concreting of the side spans with support provided by intermediate trestles. The deck is designed with a grid structure of girders. One set of girders is at the ends and another set is in the middle, which are connected by girders at an average center-to-center spacing of 4.2 m (14 feet).
A deck crane was used in the construction of the main span of the bridge. A specially designed crane with a lifting capacity of 45 tonnes was used to erect the bridge arches. The structural steel used in the bridge weighs about 13,200 tonnes. The 128 m (420 ft) high pylons are designed as free standing portals.
They are provided with two cross portal members, one at the bottom and the other at the top, below the pylon heads. The deck is connected to the end piers by bolts embedded in the pier chambers. Pylons made of 4×4 m (13×13 ft) steel boxes were constructed on the two side spans of the bridge; one set on the Kolkata side and the other on the Howrah side.
Six arches on the Kolkata side of the bridge were installed using 75 MT and 50 MT cranes, while on the Howrah end, a single 50 MT crane was used. The pylons were anchored to the piers by tie rods anchored to the base of the piers. The cables were laid from the heads of the four pylons using 32 lifting frames.
Lifting frames were mounted on top of each pylon. Sheave blocks, winches and snatch blocks were used to facilitate the lifting and the cables inside the pylon were pressed with jacks. Pressure grouting was used to fill the gaps between the cables and the high-density polyethylene (HDPE) tubes. A two-ton tower crane, fixed inside the pylon, lifted the cables into position.
The bridge has been the subject of prototype wind tunnel tests at the Indian Institute of Science in Bangalore. Bearings are used in the vertical and horizontal directions, with four segment grouted collars on the two end piers and horizontal bearings on the two middle piers to achieve stability against lateral movement.
Maurer Söhne expansion joints were provided to allow 400-millimetre (16 in) horizontal expansion at the free ends. 115-millimetre (4.5 in) fixed-end slab sill type expansion joints were used to accommodate the horizontal expansion of the joints. Other essential components provided in the bridge structure are handrails, lightning arresters, crash barriers, gas service support structures, telephone and electrical lines, lifts on pylons and a maintenance gantry.
