What made Bandra-Worli Sea-Link an engineering marvel?
If local trains are considered the lifeline of the city of dreams, the Bandra-Worli Sea Link is the pride of Mumbai. India’s first eight-lane over-sea highway connects Bandra in the city’s western suburbs to Worli in southern Mumbai. Officially called Rajiv Gandhi Sea-Link, it is the fourth largest bridge in the country after Bhupen Hazarika, the Dibang River Bridge and Mahatma Gandhi Setu. The Sea Link is a cable-stayed bridge with prestressed concrete-steel viaducts on either side and was built by the Hindustan Construction Company.
The Maharashtra State Road Transport Corporation ordered the bridge, and the first four lanes of the eight-lane road were opened to the public on June 30, 2009. A few months later, on March 24, 2010, all eight lanes were opened for public use. . It has an average daily traffic of over 37,000 vehicles and cuts the travel time between the two points by 20 to 30 minutes. The long-awaited engineering marvel weighs around 56,000 African elephants combined and is 63 times that of Qutub Minar in length.
Consumed over 90,000 tonnes of cement
The 5.6-kilometer-long cable-stayed bridge consumed more than 90,000 tonnes of cement, the equivalent of the cement used to construct five ten-story buildings in Mumbai. Bal Thackeray laid the foundation stone for the bridge in 1999, and Sonia Gandhi cut the ribbon for the same ten years later. The building authority estimated the project to take five years to complete, but it ultimately took ten years for it to become operational.
Before starting construction of the bridge, the government had planned several surveys to accurately study the surface of the seabed. Basalts, volcanic tuffs and breccias with some submarine deposits were completely covered with weathered rocks and residual soils. The Bandra-Worli Sea Link was the first infrastructure project in Mumbai to use seismic arresters. These arresters allow it to withstand earthquakes measuring up to 7.0 on the Richter scale. Nevertheless, the construction processes posed significant technical and legal challenges. Fishermen, activists and environmental enthusiasts opposed the construction of the bridge; however, the Supreme Court order finally gave the green light.
The height of the bridge is 126 meters and involved a total of 424 cables for the main carriageway, approximately 37,680 km of steel wire, 230,000 cubic meters of concrete and nearly 135 pile caps. At the height of its construction, the project involved 4,000 workers and 150 engineers. Dar Al-Handasah Consultants and Jacobs Engineering Group Inc. designed the bridge, and Lachel Felice & Associates Inc. handled the geotechnical aspect of the construction. The Hindustan Construction Company and its foreign partner, China Harbor Engineering Corporation, were the main contractors.
Three phases of construction of the Sea-Link
The construction of the bridge was divided into three main parts. The first part included the approach to the north end of the structure which was primarily a prefabricated segmental construction (PC). The second part was to look after the cable-stayed bridge of the Bandra Canal with a span of 50 m – 250 m – 250 m – 50 m, and the cable-stayed bridge of the Worli Canal has a span of 50 m – 50 m – 150 m – 50 m – 50 m. Finally, the third segment provided a southern approach structure primarily with a prefabricated segmented construction.
The construction of the gigantic bridge required heavy cranes and several other pieces of equipment, including a jack-up platform, booms, boats, crawler cranes, derrick cranes, a launching beam, a arrow to place and several others. Equipment was replenished from several countries, and a total of 130 pieces of equipment were used at a cost of 190 crore. Of the total, 25 machines were imported at the expense of 78 crore. Apart from the construction of the maritime link, its safety was one of the greatest concerns. Therefore, the Mumbai Police have stepped forward and installed high tech security measures and CCTV cameras for permanent vigilance of the project under construction.
The creation of the entire project required a reliable and non-stop power supply. The arrangements met the housing needs of diesel generator sets and automatic mains failure panels to meet the needs of the critical load, for example, surveillance services, monitoring and disposal of communication equipment such as power lines. obstruction of aviation. The contractors insisted on integrating lighting equipment into the bridge tower and the control room buildings to protect them.
Why was the bridge necessary?
Initially, Mahim’s Causeway was the only road that connected the western outskirts of the city with the bustle of the city of dreams. Congestion on the road, especially during rush hour, has created a lot of chaos. Therefore, a western highway was suggested to release congestion. The Bandra-Worli Sea Link, a bridge over Mahim Bay, came out as the first proposal of the project, which would be an alternative route to the Mahim Causeway. Initially, the cost of the project was estimated at 400 crore, but in subsequent years the cost of building the engineering marvel quadrupled.
During one of the presentations, it was revealed that one of the giant water rods in the world, the Hercules, had been brought into the final phase of the construction of the bridge, just before the infamous Mumbai rains arrived. . Hercules, as the name suggests, is so massive that it can only be used during high tides because it requires a certain depth to tread the high seas.
Today the bridge is filled with security cameras and other security-providing devices available to Mumbai Police. These additional measures ensure the safety and security of the bridge and prevent any further damage caused by wrongdoers on the bridge. In addition, the cameras also monitor the movement of boats under the bridge. The 16-lane automated toll booth charges drivers for using the sea link, and tourists say the toll was worth it.
The bridge is not accessible to pedestrians and was not built for them in the first place. Also, if cars try to stop on the bridge and take pictures, they can be fined. The government has also banned the use of two-wheelers, whether motorcycles or bicycles and three-wheelers on the sea link. Nonetheless, the sea link saves almost 260 crores per year due to the reduced congestion and the shorter length of the new route.
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