The Maharashtra State Road Development Corporation hopes to complete the “missing link” project on the Mumbai-Pune expressway by this year’s end of early 2024, The Indian Express reported. The project has had its fair share of challenges as the monsoon continues to provide a jerky path.

Engineers working 100 metres above valley amid rainfall

The 640-metre-long cable-stayed bridge of the project, which is also the most challenging part, has seen 34% completion. Engineers, who work at a height of 100 metres above the Tiger Valley, say the project will hit a major milestone in July when ‘the viaduct’ undergoes first load testing on the Pune-bound corridor. The region witnesses heavy rainfall daily and hindering the engineers’ work on the bridge. The portion comes in the ghat section which receives 50-65 mm rain daily.

MSRDC Chief Engineer Rajesh Patil told The Indian Express that on rainy days, the team is able to work on the bridge only 50% of the time. The work progresses at a slow pace when the rainfall is around 50 mm. However, if it exceeds 65 mm, the work stops.

‘Missing link’ project’s 650-m cable-stayed bridge

The cable-stayed bridge is a crucial part of the project. It has been designed to withstand wind speeds of 70 metres per second or 252 kilometres per hour. A prototype of the bridge’s design was put to a wind tunnel testing at Force Institute in Denmark earlier.

The bridge’s maximum span length is 305 metres (mid-span), while end-spans’ length on either side is 165 metres. The maximum height of pylons, which support the cables, is 170 metres. Had the bridge been a traditional one the number of pylons and piers would have been four times more. However, that would have caused trouble in this case as the bridge goes over the Sahyadri Valley and every pier would need to be 100 metres high. “As it’s a cable-stayed bridge, only four pylons and eight piers are required. In a traditional bridge, the number of pylons and piers would have been four times that number posing engineering challenges, taken longer time to complete the project, required more resources and money,” Patil said.

The bridge’s foundation work was taken up in the last monsoon season.

As of now, the pylon construction is going on and the team has reached an average height of 65 mteres. The bridge has four pylons. The construction of the deck slab will start once the pylons reach a height of 100 metres. Once a 9-metre-long deck slab is ready,it will be tied with the cables to the pylon. The cables will be tied to the deck slab at 152 metres from either side as the mid-span length is 305 metres.

The MSRDC plans to start the deck slab work and finish at least one pylon by August. There are two viaducts. While the one for the Pune-bound corridor is nearly complete, the one for Mumbai-bound corridor is also progressing.

About the project

With the 13-km-long project, costing Rs 6,600-crore, the MSRDC aims to resolve the annual monsoon woe of traffic gridlocks at Khandala due to boulders and morum from hillocks flanking the road. On Mumbai’s end, the project starts at Khopoli, bypasses the expressway via an 840-metre-long viaduct and enters a 1.75-kilometre-long tunnel. After that it goes over to the cable-stayed bridge at a height of 100 feet. Thereafter it enters a 8.9-kilometre-long tunnel. A part of this tunnel lies 170 feet underground with Lonavala lake resting on top of it. It finally emerges near the Sinhgad Institute. The distance between Khopoli and the institute is 19 kilometres along the expressway. The ‘missing link’ will cut the distance by 5.7 kilometres and save 20-30 minutes.

The excavation work for the two tunnels of the project has been completed and the finishing work, like surfacing and plumbing, is in progress.