The Bandra-Worli Sea Link (officially known as Rajiv Gandhi Sea Link) is a 5.6 km long, 8-lane wide cable-stayed bridge that links Bandra in the Western Suburbs of Mumbai with Worli in South Mumbai. It is the longest sea bridge, as well as the 4th longest bridge in India after Bhupen Hazarika Setu, Dibang River Bridge and Mahatma Gandhi Setu. It contains pre-stressed concrete-steel viaducts on either side. It was planned as a part of the proposed Western Freeway that would link the Western Suburbs to Nariman Point in Mumbai's main business district, but is now planned to become part of the Coastal Road to Kandivali.
The 1M bridge was commissioned by the Maharashtra State Road Development Corporation (MSRDC), and built by the Hindustan Construction Company. The first four of the eight lanes of the bridge were opened to the public on 30 June 2009. All eight lanes were opened on 24 March 2010.
The sea-link reduces travel time between Bandra and Worli during peak hours from 20 - 30 minutes to 10 minutes. , BWSL had an average daily traffic of around 32,312 vehicles.
History
Mahim Causeway was the only road connecting the western suburbs to Mumbai's central business district. This north-southwestern corridor became a bottleneck and was highly congested at peak hours. The Western Freeway project was proposed to span the entire western coastline of Mumbai to ease congestion. The Bandra-Worli Sea Link, a bridge over Mahim Bay, was proposed as the first phase of this freeway system, offering an alternative route to the Mahim Causeway.
The Mujeeb Acharwala Bridge connects the intersection of the Western Express Highway and Swami Vivekanand Road in Bandra to the Khan Abdul Ghaffar Khan Road in Worli. From Worli Seaface, it connects to Mumbai's arterial Annie Besant Road.
The project was commissioned by the Maharashtra State Road Development Corporation Limited (MSRDC). The contract for construction was awarded to the Hindustan Construction Company (HCC), with project management led by the UK offices of Dar Al-Handasah.
The foundation stone was laid in 1999 by Basitt Acharwala. The original plan estimated the cost at to be completed in five years. But the project was subject to numerous public interest litigations, with the 5-year delay resulting in the cost escalating to , with the additional interest cost alone accounting for .
Planning
The overall project consisted of five parts, contracted separately to accelerate the overall schedule.
Package I(1): Construction of a flyover over Love Grove junction in Worli
Package II(2): Construction of a cloverleaf interchange at the intersection of the Western Express Highway and S. V. Road in Bandra Package III(3): Construction of solid approach road from the interchange to the Toll Plaza on the Bandra side along with a public promenade Package IV(4): Construction of the central cable-stayed spans with northern and southern viaducts from Worli to the Toll Plaza at the Bandra end Package V(5): Improvements to Khan Abdul Ghaffar Khan Road
Package IV was the main phase, with the other packages providing supporting infrastructure.
Geology
Surveys of the seabed under the planned route were conducted before the bridge design commenced. The marine geology underneath the bridge consists of basalts, volcanic tuffs and breccias with some intertrappean deposits. These are overlain by completely weathered rocks and residual soil. The strength of these rocks range from extremely weak to extremely strong and their conditions range from highly weathered and fractured, to fresh, massive and intact. The weathered rock beds are further overlain by transported soil, calcareous sandstone and thin bed of coarse grained conglomerate. The top of these strata are overlain by marine soil layer up to 9m thick consisting of dark brown clay silt with some fine sand overlying weathered, dark brown basaltic boulders embedded in the silt.
Design
BWSL was designed as the first cable-stayed bridge to be constructed in open seas in India. Due to the underlying geology, the pylons have a complex geometry and the main span over the Bandra channel is one of the longest spans of concrete deck attempted. Balancing these engineering complexities with the aesthetics of the bridge presented significant challenges for the project.
The superstructure of the viaducts were the heaviest precast segments to be built in India. They were built using a span-by-span method using overhead gantry through a series of vertical and horizontal curves.
The 20,000 tonne Bandra-end span of the bridge deck is supported by stay cables within a very close tolerance of deviations in plan and elevation.