Linking Coastal Road to Sea Link: Girders for bowstring arch bridge to be launched at night

“The girders arrived in Mumbai around 4 am Thursday. At first the barges will be affixed and centered in a particular position using winches to prevent them from drifting away. After they are centered, they will be hoisted and erected on Thursday night when tidal conditions are neither high nor low,” said an official. The process of launching girders will take more than two hours, the officials said.

After the girders are launched, authorities will concretise them in order to lay asphalt roads, following a process of waterproofing. Officials said that the balance work will take around one month. “This girder will be the main access point for vehicles to enter and exit the coastal road from BWSL. Launching the girder will mark the end of the project’s final step,” the official said.

The girder was initially supposed to be launched between April 18–19, but with Mumbai reeling under a heatwave the drive was deferred by a week.

The girders are prefabricated structures and the launch is being taken up in waters since there is no adequate land strip available in Worli.

The making of this bridge was a major hurdle for civic authorities to overcome in their endeavour to complete the MCRP project.

The main bone of contention between the fishing community and BMC was the gap to be maintained between the pillars on which the bridge was to be created. The fishing community demanded that the gap be 200 metres, while BMC’s was confident that 60 metres would provide them a safe passage.

Following the dischord, the fisherfolk went on a strike and BMC had to revise the plan and remove one pillar to provide a wider navigation span to the boats. Since engineers could not erect an additional pillar, and the distance between the existing mono-piles increased owing to removal of one pillar, the civic body opted for a ‘bow-string’ girder bridge.

The speciality of such arch bridges is that spans are held together through high-tension chords instead of having a base support such as pillars. The chord forms an arch shaped girder from the outside and holds the ends of the bridge tightly with the surface.

At present the coastal road is operational only between 8 am and 8 pm on weekdays for south-bound traffic and officials are planning to have the entire road operational by May-end.