India's Mega Projects: 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 accounts for Mumbai's pride. India's first eight-lane freeway over the open sea connects Bandra in the western suburbs of the city to Worli in South Mumbai. Officially called Rajiv Gandhi Sea-Link, it is the fourth largest Bridge of the country after Bhupen Hazarika, Dibang River Bridge and the Mahatma Gandhi Setu. The Sea Link is a cable-stayed bridge with pre-stressed concrete-steel viaducts on either side and was built by the Hindustan Construction Company.

The Maharashtra State Road Transport Corporation commissioned the Bridge, and the first four lanes of the eight-lane path were opened to the public on June 30, 2009. A few months later, on March 24, 2010, all eight lanes were made open for public use. It has an average daily traffic of more than 37,000 vehicles and reduces the travel time between the two points by 20 to 30 minutes. The long-awaited engineering marvel weighs approximately as much as 56,000 African elephants put together, and its length is 63 times that of Qutub Minar.

Consumed More Than 90,000 Tonnes Of Cement

The 5.6 kilometres long cable-stayed Bridge has consumed more than 90,000 tonnes of cement, equivalent to the cement used for constructing five buildings of ten storeys each 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 construction authority had estimated five years to complete the project, but it eventually took ten years to become functional.

Before beginning the construction of the Bridge, the government had planned several surveys to study the seabed surface accurately. The basalts, volcanic tuffs and breccias with some seabed deposits were overlain completely by weathered rocks and residual soil. The Bandra–Worli Sea Link was the first infrastructure project in Mumbai to use seismic arresters. These arresters enable it to withstand earthquakes measuring up to 7.0 on the Richter scale. Nonetheless, the construction processes posed significant engineering challenges and legal challenges. Fishers, activists and environmental enthusiasts had opposed the construction of the Bridge; however, Supreme Court's order finally gave the go-ahead.

The height of the Bridge is 126 metres and has involved a total of 424 cables for the main roadway, about 37,680km of steel wire, 230,000 metre cube of concrete and nearly 135 pile caps. At the peak of its construction, the project involved 4,000 workers and 150 engineers. Dar Al-Handasah Consultants and the Jacobs Engineering Group Inc. designed the Bridge, and Lachel Felice & Associates Inc. looked after the geotechnical engineering aspect of the construction. The Hindustan Construction Company and its foreign partner, China Harbour Engineering Corporation, were the main contractors.

Three Phases Of Construction of The Sea-Link

The construction of the Bridge was divided into three parts primarily. The first part comprised the north-end approach of the structure that was mainly precast (PC) segmental construction. The second part involved looking after the Cable-stayed bridge at Bandra Channel with 50m – 250m – 250m – 50m span arrangement, and the Cable-Stayed Bridge at Worli channel is with 50m – 50m – 150m – 50m – 50m span arrangement. Finally, the third segment provided a south-end approach structure mainly with precast segmental construction.

The Construction of the mammoth bridge required heavy cranes and several other pieces of equipment, including a Jack-up platform, floating barrages, boats, crawler cranes, derrick cranes, launching truss, placer boom and several others. The equipment was pieced together from several countries, and a total of 130 pieces of equipment were used at the cost of ₹190 crores. Out of the total, 25 machines were imported at the expense of ₹78 crores. Apart from the construction of the sea link, its security was one of the gravest concerns. Therefore, the Mumbai Police stepped forward and installed high-tech security measures and CCTV cameras for round the clock vigilance of the under-construction project.

The creation of the entire project demanded a reliable and non-stop power supply. The arrangements catered to the needs of housing diesel generator sets and auto mains failure panels to cater to the needs of critical load, for instance, monitoring, surveillance and communication equipment arrangement services like aviation obstruction lines. The contractors emphasised incorporating lighting equipment at the bridge tower and control room buildings to protect them.

Why Was The Bridge Needed?

Initially, the Mahim Causeway was the only route that connected the city's western suburbs to the hustle-bustle of the city of dreams. The congestion on the road, especially during peak hours, created a lot of chaos. Therefore, a western freeway was suggested to release the congestion. The Bandra-Worli Sea Link, a bridge over the Mahim Bay, came out as the first proposal of the project, which would be an alternative road to the Mahim causeway. Initially, the project cost was estimated at ₹400 crores, but the subsequent years increased the cost of building the engineering marvel over four times.

During one of the presentations, it was revealed that one of the giant water canes in the world, the Hercules, was brought in the final phase of the bridge construction, just before the arrival of the famous Mumbai rains. Hercules, as the name suggests, is so massive that it can only be used during high tides as it requires a certain depth to tread the high seas.

Today, the Bridge is filled with security cameras and other security ensuring devices at the Mumbai Police's disposal. Such extra measures ensure the safety and security of the Bridge and avoid any additional damage by miscreants on the Bridge. Moreover, the cameras also check the boat traffic below the Bridge. The 16-lane automated toll plaza charges drivers for using the sea-link, and the tourists mention that the toll charge was worth it.

The Bridge is not accessible for pedestrians and was not built for them in the first place. Moreover, if any cars try to stop on the Bridge and take pictures, they are liable to be fined. The government has also banned using two-wheelers, be it motorbikes or bicycles and three-wheelers on the sea-link. Nonetheless, the sea link helps to save nearly ₹260 crores annually because of reduced congestion and the shorter length of the new route.

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