Coastal road-sea link gap to be bridged by April 16 on southbound arm

The BMC will launch its most crucial 120-metre girder with a bowstring arch to connect the southbound arm of the coastal road with the Bandra-Worli sea link by April 16 or 17

MUMBAI: The BMC will launch its most crucial 120-metre girder with a bowstring arch to connect the southbound arm of the coastal road with the Bandra-Worli sea link by April 16 or 17.

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M M Swami, deputy chief engineer of the coastal road, said that erection works were the most challenging part of the proposal, given the rocky seabed. Conventional lifting and assembly by cranes in situ cannot be deployed in these conditions. In the southbound arm, three girders of 46-metre, 44-metre and 60-metre spans have already been launched.

“On April 12, the 120-metre bowstring arch bridge, assembled at Nhava village jetty, will be loaded in a barge (a floating platform) that will start moving towards the site at Worli and will reach by April 15-16,” said Swami. Depending on the weather conditions, the arch bridge will be placed on the pier by April 16-17.”

Eight girders will bridge the gap with an arch bridge between the coastal road’s Worli end and the sea link on the south-bound arm (Worli-Marine Drive) as well as the north-bound arm. The bridge between the coastal road and the sea link will be 850 metres long, of which 270 metres will be made of steel and the remaining will be concrete.

AECOM is the BMC’s general consultant for the south coastal road project and takes care of contracts and design handling on behalf of the civic body. After the BMC’s decision to revise the originally planned navigation span from 60 metres to 120 metres (after PILs and objections from NGOs and local fishermen), Vipul Surana, team leader at AECOM, said the team had a series of discussions with the inhouse design team, and various proposals were studied by stakeholders.

“The change in design had an overall impact on the project’s timelines,” said Surana. “Also, the span was to be erected mid-sea without support from the bottom since the navigation span had to be unobstructed. After various deliberations, the proposal for a prefabricated and pre-assembled structure proposed by Hindustan Construction Company (HCC) was reviewed and approved by the project management consultants, general consultants and the BMC.”

Arvind Singh, project manager of the HCC-Hyundai Development Corporation Joint Venture, which is constructing the coastal road, said, “Given its complexity, the structure’s design was given to the DM Engineering-Spectrum consortium, which has experience of designing similar structures. DM Engineering provided the model of the arch with a 120-metre navigation span and composite deck with span lengths of 46 metres, 60 metres and 44 metres.”

Surana further explained that a forecast of good weather was needed before the lifting operation of the 120-metre girder arch bridge could be carried out. “A weather condition with no heavy rain, lightning or wind speed of 20 metres per second or less is considered good weather,” he said. “For safety purposes, adequate lighting should be made available to ensure that the operations can be continued at night if necessary. Safety gear and equipment will be made available at convenient locations.”

One of the four girders is already launched in the north-bound arm. “The other two girders are ready at the Nhava assembly yard and will be launched later in April. The arch for the north-bound arm will be launched in May in a fair-weather window,” concluded Surana.