Bandra-Worli Sea Link
Encyclopedia
The Bandra–Worli Sea Link (BWSL) ( Wāndre Warḷi Setu), also known as the Rajiv Gandhi Sea Link , is a cable-stayed bridge
with pre-stressed concrete-steel viaduct
s on either side, that links Bandra and the western suburbs of Mumbai with Worli
. The bridge is a part of the proposed West Island Freeway
system that links the western suburbs to Nariman Point
in Mumbai's main business district.
The bridge was commissioned by the Maharashtra State Road Development Corporation
(MSRDC), and built by the Hindustan Construction Company
. The first 4 of the 8 lanes of the bridge were opened to the public on 30 June 2009.. All the 8 lanes were opened to traffic on 24 March 2010.
BWSL reduces travel time between Bandra and Worli from 45–60 minutes during peak hours to 7 minutes. As of October 2009, BWSL had an average daily traffic
of around 37,500 vehicles.
was the only road link 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 West Island Freeway project was proposed to span the entire western coastline of Mumbai to ease congestion. BWSL, a bridge over Mahim Bay
, was proposed as the first phase of this freeway system. offering an alternate route to the Mahim Causeway.
BWSL connects the intersection of the Western Express Highway
and Swami Vivekanand Road (S.V. Road) in Bandra to the Khan Abdul Ghaffar Khan
Road (Worli Seaface) 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 Bal Thackeray
. The original plan estimated the cost at to be completed in 5 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 .
BWSL was opened to the public in June 2009. It was named in the memory of late Prime Minister Rajiv Gandhi
. All the 8 lanes were opened to traffic in March 2010.
Package IV was the main phase of Bandra-Worli Sea Link Project, with the other packages providing supporting infrastructure for the sea link.
. 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 20000 metric ton Bandra-end span of the bridge deck is supported by stay cable
s within a very close tolerance of deviations in plan and elevation.
The foundations for the BWSL's cable-stayed bridges consist of 120 reinforced concrete piles
of 2000 millimetres (6.6 ft) diameter. Those for the viaducts consist of 484 piles of 1500 millimetres (4.9 ft). These 604 piles were driven between 6m and 34m into the substrate in geotechnical conditions that varied from highly weathered volcanic material to massive high strength rocks.
The bridge's pylon towers gradually decrease in cross-section with height. They have horizontal grooves every 3m in height, which permitted inserts. Vertical grooves in the circular sections require special form liners, as well as require attention for de-shuttering. The tower legs are inclined in two directions, which presented challenges in alignment and climbing of soldiers. Construction joints were permitted at 3m intervals only.
To build the pylons, Doka of Austria was commissioned to build a custom automatic climbing shutter formwork system, based on their SKE-100 automatic climbing shutter system. This was fabricated on site and employed to execute all tower leg lifts below deck level.
The bridge consists of 3 distinct parts: the north end viaduct, the central cable-stayed spans and the south end viaduct. Both the viaducts used precast segmental construction. The cable-stayed bridge on the Bandra channel has a 50m-250m-250m-50m span arrangement and on the Worli channel it has a 50m-50m-150m-50m-50m span arrangement.
The viaducts were built utilising pre-cast, post-tensioned, segmental concrete-steel box girder sections. An overhead gantry crane with self-launching capability was custom built on the site to lay the superstructure of the precast segments. The Pre-Cast segments are joined together using high strength epoxy glue with nominal pre-stressing initially. The end segments adjacent to the pier are short segments "cast-in-situ joints". Geometrical adjustments of the span are made before primary continuous tendons are stressed.
Segment types are further defined by the changes in the web thickness and type of diaphragms cast in cell. The segment weights vary from 110 tonnes to 140 tonnes per segment. The segment length varies from 3000 mm to 3200 mm. Deck post tensioning is performed at the completion of the erection of each 50m bridge span.
The cable-stayed portion of the Worli
channel is 350 metres (1,148.3 ft) in length between expansion joints and consists of one 150 metres cable supported main span flanked on each side by two 50 metres conventional approach spans. A centre tower, with an overall height of 55 metres, supports the superstructure above the pile cap level by means of four planes of cable stay in a semi-harp arrangement. Cable spacing here is also 6.0 metres along the bridge deck.
The superstructure comprises twin precast concrete box girders with a fish belly cross sectional shape, identical to the approaches. A typical Pre-Cast segment length is 3.0 metres with the heaviest superstructure segment approaching 140 tonnes. Balanced cantilever construction is used for erecting the cable supported superstructure as compared to span-by-span construction for the approaches. For every second segment, cable anchorages are provided.
A total of 264 cable stays are used at Bandra channel with cable lengths varying from approximately 85 metres minimum to nearly 250 metres maximum. The tower is cast in-situ reinforced concrete using the climbing form method of construction. The overall tower configuration is an inverted "Y" shape with the inclined legs oriented along the axis of the bridge. Tower cable anchorage recesses are achieved by use of formed pockets and transverse and longitudinal bar post-tensioning is provided in the tower head to resist local cable forces.
A total of 160 cable stays are used at Worli channel with cable lengths varying from approximately 30 metres minimum to nearly 80 metres maximum. Like the Bandra channel, the tower here is also cast in-situ reinforced concrete using the climbing form method of construction but the overall tower configuration is "I" shape with the inclined legs. Similarly, tower cable anchorage recesses are achieved by use of formed pockets.
The foundations for the main tower comprise 2 metre-drilled shafts of 25 metres length each. Cofferdam and tremie seal construction have been used to construct the six metre deep foundation in the dry.
At both ends, the toll collection options include:
, monitoring and control systems. It comprises CCTVs, automatic traffic counters and vehicle classification system, variable message signs, remote weather information system and emergency telephones. The control centre is located near the toll plaza along with the electronic tolling controls. The control system uses fibre-optic cables running the entire span of the BWSL. The toll management system and advanced traffic management system was installed by Efkon India.
For traffic enforcement, the bridge includes facilities for vehicles to pull over when stopped by enforcement officers or in the event of a breakdown.
The pillars and the towers supporting the bridge are protected by buoys designed to withstand explosions and collisions. These inflated buoys surround each pillar of the sea link to avoid any damage.
The bridge tower and the control centers feature lightning protection, designed to protect the bridge monitoring, communication and power equipment from possible surges.
s and auto mains failure panels for critical loads, such as monitoring, surveillance, emergency equipment and communication services including aviation and obstruction indicators. BWSL exclusively uses energy saving illlumination systems.
Cable-stayed bridge
A cable-stayed bridge is a bridge that consists of one or more columns , with cables supporting the bridge deck....
with pre-stressed concrete-steel viaduct
Viaduct
A viaduct is a bridge composed of several small spans. The term viaduct is derived from the Latin via for road and ducere to lead something. However, the Ancient Romans did not use that term per se; it is a modern derivation from an analogy with aqueduct. Like the Roman aqueducts, many early...
s on either side, that links Bandra and the western suburbs of Mumbai with Worli
Worli
-History:Worli was one of the original seven islands that constituted the city of Mumbai. Although primarily a fishing village, the Worli Fort, a British fort that is now in ruins, is located there. Its original resident was the legendary Dishankeshwar Kalsi who has also been recognized in several...
. The bridge is a part of the proposed West Island Freeway
West Island Freeway
The Western Freeway is an ambitious project that envisions the construction of multiple bridges over the Arabian Sea to reduce traffic-congestion between the suburbs and the city. The first phase of the project, known as the Bandra-Worli Sea Link, was completed in June 2009, and links Bandra in the...
system that links the western suburbs to Nariman Point
Nariman Point
Nariman Point is Mumbai's premier business district and country's first central business district. It was named after Khursheed Framji Nariman, a Parsi visionary. The area is situated on land reclaimed from the sea. It had the distinction of having the highest commercial real estate rental space...
in Mumbai's main business district.
The bridge was commissioned by the Maharashtra State Road Development Corporation
Maharashtra State Road Development Corporation
Maharashtra State Road Development Corporation Limited , commonly abbreviated as MSRDC, is an Indian Public limited company fully owned by the Government of Maharashtra. MSRDC was established on July 9, 1996 and incorporated as a public limited company under the Companies Act 1956 on August 2, 1996...
(MSRDC), and built by the Hindustan Construction Company
Hindustan Construction Company
Hindustan Construction Company is a construction company based in Mumbai, India, founded in 1926. HCC works in various sectors including transportation, power, marine, oil and gas pipeline construction, irrigation, utilities and urban infrastructure. HCC specializes in large-scale civil...
. The first 4 of the 8 lanes of the bridge were opened to the public on 30 June 2009.. All the 8 lanes were opened to traffic on 24 March 2010.
BWSL reduces travel time between Bandra and Worli from 45–60 minutes during peak hours to 7 minutes. As of October 2009, BWSL had an average daily traffic
Traffic
Traffic on roads may consist of pedestrians, ridden or herded animals, vehicles, streetcars and other conveyances, either singly or together, while using the public way for purposes of travel...
of around 37,500 vehicles.
History
Mahim CausewayMahim Causeway
The Mahim Causeway is a vital link road connecting the city of Mumbai with its northern suburbs. The causeway links the neighbourhoods of Mahim to the south with Bandra to the north....
was the only road link 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 West Island Freeway project was proposed to span the entire western coastline of Mumbai to ease congestion. BWSL, a bridge over Mahim Bay
Mahim Bay
Mahim Bay is a large bay, part of the Arabian Sea in Mumbai India. The southern end is Worli, northern end is Bandra Reclamation and Mahim is in the centre. The bay was named after the islands of Mahim and Salsette were merged in the early 19th century...
, was proposed as the first phase of this freeway system. offering an alternate route to the Mahim Causeway.
BWSL connects the intersection of the Western Express Highway
Western Express Highway
The Western Express Highway is a major north-south 8-10 lane arterial road in Mumbai, India, stretching from the suburb of Bandra to Dahisar. The highway begins near the Mahim Creek and extends to the Mira-Dahisar toll booth in the northern limit of the city. Beyond the city limits, it continues...
and Swami Vivekanand Road (S.V. Road) in Bandra to the Khan Abdul Ghaffar Khan
Khan Abdul Ghaffar Khan
Khan Abdul Ghaffar Khan was an Afghan, Pashtun political and spiritual leader known for his non-violent opposition to British Rule in India...
Road (Worli Seaface) in Worli. From Worli Seaface, it connects to Mumbai's arterial Annie Besant
Annie Besant
Annie Besant was a prominent British Theosophist, women's rights activist, writer and orator and supporter of Irish and Indian self rule.She was married at 19 to Frank Besant but separated from him over religious differences. She then became a prominent speaker for the National Secular Society ...
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
Dar Al-Handasah
Dar Al-Handasah is an international leading project design, management and supervision consultancy and founding member of the Dar Group. It is a multidisciplinary consulting organization for engineering, architecture, planning, environment, project management, and economics...
.
The foundation stone was laid in 1999 by Bal Thackeray
Bal Thackeray
Bal Keshav Thackeray , popularly known as Balasaheb Thackeray, is an Indian politician, founder and chief of the Shiv Sena, a right-wing Hindu nationalist, and Marathi ethnocentric party active mainly in the western Indian state of Maharashtra.Born in Pune, Thackeray began his professional career...
. The original plan estimated the cost at to be completed in 5 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 .
BWSL was opened to the public in June 2009. It was named in the memory of late Prime Minister Rajiv Gandhi
Rajiv Gandhi
Rajiv Ratna Gandhi was the sixth Prime Minister of India . He took office after his mother's assassination on 31 October 1984; he himself was assassinated on 21 May 1991. He became the youngest Prime Minister of India when he took office at the age of 40.Rajiv Gandhi was the elder son of Indira...
. All the 8 lanes were opened to traffic in March 2010.
Planning
The overall project consisted of five distinct parts, contracted separately to accelerate the overall schedule.- Package I: Construction of a flyoverOverpassAn overpass is a bridge, road, railway or similar structure that crosses over another road or railway...
over Love Grove junction in Worli - Package II: Construction of a cloverleaf interchangeCloverleaf interchangeA cloverleaf interchange is a two-level interchange in which left turns, reverse direction in left-driving regions, are handled by ramp roads...
at the intersection of the Western Express Highway and S.V. Road in Bandra - Package III: Construction of solid approach road from the interchange to the Toll Plaza on the Bandra side along with a public promenade
- Package IV: Construction of the central cable-stayed spans with northern and southern viaducts from Worli to the Toll Plaza at the Bandra end
- Package V: Improvements to Khan Abdul Gaffar Khan Road
Package IV was the main phase of Bandra-Worli Sea Link Project, with the other packages providing supporting infrastructure for the sea link.
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 IndiaIndia
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
. 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 20000 metric ton Bandra-end span of the bridge deck is supported by stay cable
Cable
A cable is two or more wires running side by side and bonded, twisted or braided together to form a single assembly. In mechanics cables, otherwise known as wire ropes, are used for lifting, hauling and towing or conveying force through tension. In electrical engineering cables are used to carry...
s within a very close tolerance of deviations in plan and elevation.
Foundation and substructure
The construction of the bridge's structure presented major engineering challenges. These included the highly variable geotechnical conditions due to the underlying marine geology of the seabed. At times, even for plan area of a single pile had a highly uneven foundation bed. Further compilcations included the presence of a variable intertidal zone, with parts of the foundation bed exposed in low tide and submerged in high tide.The foundations for the BWSL's cable-stayed bridges consist of 120 reinforced concrete piles
Deep foundation
A deep foundation is a type of foundation distinguished from shallow foundations by the depth they are embedded into the ground. There are many reasons a geotechnical engineer would recommend a deep foundation over a shallow foundation, but some of the common reasons are very large design loads, a...
of 2000 millimetres (6.6 ft) diameter. Those for the viaducts consist of 484 piles of 1500 millimetres (4.9 ft). These 604 piles were driven between 6m and 34m into the substrate in geotechnical conditions that varied from highly weathered volcanic material to massive high strength rocks.
Pylon tower
The largest pylons for the bridge consist of diamond shaped 128 metres (419.9 ft) high concrete tower featuring flaring lower legs, converging upper legs, a unified tower head housing the stays and a continuously varying cross section along the height of tower.The bridge's pylon towers gradually decrease in cross-section with height. They have horizontal grooves every 3m in height, which permitted inserts. Vertical grooves in the circular sections require special form liners, as well as require attention for de-shuttering. The tower legs are inclined in two directions, which presented challenges in alignment and climbing of soldiers. Construction joints were permitted at 3m intervals only.
To build the pylons, Doka of Austria was commissioned to build a custom automatic climbing shutter formwork system, based on their SKE-100 automatic climbing shutter system. This was fabricated on site and employed to execute all tower leg lifts below deck level.
Pre-cast yard
The pre-cast yard was located on reclaimed land. The yard catered to casting, storing and handling of 2342 concrete-steel pre-cast segments for the project. The storage capacity requirement of yard was about 470 precast segments. As the area available was limited, the segments were stored in stacks of up to three layers.Structure
BWSL consists of twin continuous concrete box girder bridge sections for traffic in each direction. Each bridge section, except at the cable-stayed portion, is supported on piers typically spaced 50 metres (164 ft) apart. Each section is designed to support four lanes of traffic with break-down lanes and concrete barriers. Sections also provide for service side-walks on one side. The bridge alignment is defined with vertical and horizontal curves.The bridge consists of 3 distinct parts: the north end viaduct, the central cable-stayed spans and the south end viaduct. Both the viaducts used precast segmental construction. The cable-stayed bridge on the Bandra channel has a 50m-250m-250m-50m span arrangement and on the Worli channel it has a 50m-50m-150m-50m-50m span arrangement.
Northern & Southern viaducts
The viaducts on either side of the central cable-stayed spans are arranged in 300 metre units consisting of six continuous spans of 50 metres each. Expansion joints are provided at each end of the units. The superstructure and substructure are designed in accordance with IRC codes. Specifications conform to the IRC standard with supplementary specifications covering special items. The foundation consists of 1.5 metres diameter drilled piles (4 nos. for each pier) with pile caps. Bridge bearings are of Disc Type.The viaducts were built utilising pre-cast, post-tensioned, segmental concrete-steel box girder sections. An overhead gantry crane with self-launching capability was custom built on the site to lay the superstructure of the precast segments. The Pre-Cast segments are joined together using high strength epoxy glue with nominal pre-stressing initially. The end segments adjacent to the pier are short segments "cast-in-situ joints". Geometrical adjustments of the span are made before primary continuous tendons are stressed.
Segment types are further defined by the changes in the web thickness and type of diaphragms cast in cell. The segment weights vary from 110 tonnes to 140 tonnes per segment. The segment length varies from 3000 mm to 3200 mm. Deck post tensioning is performed at the completion of the erection of each 50m bridge span.
Cable-stayed spans
The cable-stayed portion of the Bandra channel is 600 metres (1,968.5 ft) in length between expansion joints and consists of two 250-metre cable supported main spans flanked by 50 metres conventional approach spans. A centre tower, with an overall height of 128 metres above pile cap level, supports the superstructure by means of four planes of cable stay in a semi-harp arrangement. Cable spacing is 6.0 metres along the bridge deck.The cable-stayed portion of the Worli
Worli
-History:Worli was one of the original seven islands that constituted the city of Mumbai. Although primarily a fishing village, the Worli Fort, a British fort that is now in ruins, is located there. Its original resident was the legendary Dishankeshwar Kalsi who has also been recognized in several...
channel is 350 metres (1,148.3 ft) in length between expansion joints and consists of one 150 metres cable supported main span flanked on each side by two 50 metres conventional approach spans. A centre tower, with an overall height of 55 metres, supports the superstructure above the pile cap level by means of four planes of cable stay in a semi-harp arrangement. Cable spacing here is also 6.0 metres along the bridge deck.
The superstructure comprises twin precast concrete box girders with a fish belly cross sectional shape, identical to the approaches. A typical Pre-Cast segment length is 3.0 metres with the heaviest superstructure segment approaching 140 tonnes. Balanced cantilever construction is used for erecting the cable supported superstructure as compared to span-by-span construction for the approaches. For every second segment, cable anchorages are provided.
A total of 264 cable stays are used at Bandra channel with cable lengths varying from approximately 85 metres minimum to nearly 250 metres maximum. The tower is cast in-situ reinforced concrete using the climbing form method of construction. The overall tower configuration is an inverted "Y" shape with the inclined legs oriented along the axis of the bridge. Tower cable anchorage recesses are achieved by use of formed pockets and transverse and longitudinal bar post-tensioning is provided in the tower head to resist local cable forces.
A total of 160 cable stays are used at Worli channel with cable lengths varying from approximately 30 metres minimum to nearly 80 metres maximum. Like the Bandra channel, the tower here is also cast in-situ reinforced concrete using the climbing form method of construction but the overall tower configuration is "I" shape with the inclined legs. Similarly, tower cable anchorage recesses are achieved by use of formed pockets.
The foundations for the main tower comprise 2 metre-drilled shafts of 25 metres length each. Cofferdam and tremie seal construction have been used to construct the six metre deep foundation in the dry.
Toll collection
The Bandra end of the toll plaza has 16 approach lanes. The toll plaza is equipped with an electronic toll collection system.At both ends, the toll collection options include:
- Automatic electronic payment system through On-board Units mounted on vehicles for frequent-commuters that enable vehicles to pass without stopping
- Semi-automatic cash-less electronic payment via a smart card in unattended lanes
- Manual toll collection for payment by cash, to a toll attendant
Monitoring
An intelligent bridge management system (IBS) provides traffic information, surveillanceSurveillance
Surveillance is the monitoring of the behavior, activities, or other changing information, usually of people. It is sometimes done in a surreptitious manner...
, monitoring and control systems. It comprises CCTVs, automatic traffic counters and vehicle classification system, variable message signs, remote weather information system and emergency telephones. The control centre is located near the toll plaza along with the electronic tolling controls. The control system uses fibre-optic cables running the entire span of the BWSL. The toll management system and advanced traffic management system was installed by Efkon India.
For traffic enforcement, the bridge includes facilities for vehicles to pull over when stopped by enforcement officers or in the event of a breakdown.
Security
The bridge uses mobile explosive scanners for vehicles traveling on the sea link. Scans take less than 20 seconds for each vehicle with sensors above and below the vehicles. Over 180 cars can be scanned per hour by each scanner.The pillars and the towers supporting the bridge are protected by buoys designed to withstand explosions and collisions. These inflated buoys surround each pillar of the sea link to avoid any damage.
The bridge tower and the control centers feature lightning protection, designed to protect the bridge monitoring, communication and power equipment from possible surges.
Power supply & lighting
The bridge has a reliable and redundant power supply, backed up by diesel generatorDiesel generator
A diesel generator is the combination of a diesel engine with an electrical generator to generate electrical energy....
s and auto mains failure panels for critical loads, such as monitoring, surveillance, emergency equipment and communication services including aviation and obstruction indicators. BWSL exclusively uses energy saving illlumination systems.
See also
- Pamban BridgePamban BridgeThe Pamban Bridge is a cantilever bridge on the Palk Strait connects Rameswaram on Pamban Island to mainland India. It refers to both the road bridge and the cantilever railway bridge, though primarily it means the latter. It was India's first sea bridge...
- Worli-Haji Ali Sea LinkWorli-Haji Ali Sea LinkWorli-Haji Ali Sea Link is a proposed bridge with pre-stressed concrete viaduct approaches It will link Worli to Haji Ali section over sea...
- List of longest bridges in the world
- List of longest bridges above water in India
External links
- Bandra-Worli Sealink Project
- Bandra-Worli Sea Link Project official website
- Bandra-Worli Sea Link: A hi-tech incompetence? from The Economic TimesThe Economic TimesThe Economic Times is an English-language Indian daily newspaper published by the Bennett, Coleman & Co. Ltd.. The Economic Times was started in 1961. It is the most popular and widely read financial daily in India, read by more than 8 lakh people...
- Bandra-Worli Sealink Night Photograph