In a few months, commuters will be driving on steel decks in places where the Metro III underground stations are being constructed. While the Mumbai Metro Rail Corporation (MMRC) has barricaded one side of the road for most of the stations under construction, by December, it will require more space. As part of their traffic management plan, the MMRC proposes to use decking to allow smooth movement of vehicles.
“To construct the station underground, we will have to dig up most part of the road. We will then cover it with decks supported by king posts. We can then work underground while traffic can move unhindered above,” said S K Gupta, Director (Projects), MMRC.
King posts are central vertical posts that provide support to the decks above them. The 26 stations along the 33.5-km corridor will be constructed after excavating the ground up to a depth of 25 metres. The trench will then be covered by the steel decks. While most of the stations will be constructed by the cut and cover method, seven stations — Hutatma Chowk, Kalbadevi, Girgaum, Grant Road, Shitladevi, Santacruz and Marol Naka — will be constructed using a combination of cut and cover and the New Austrian Tunnelling Method (NATM).
However, the traffic plan for every station will be different based on its location and the contractor. “Stations like Cuffe Parade, CST, Siddhivinayak, Santacruz and CSIA (International) Metro stations will not require decking as their construction is not obstructing vehicle movement. For the Dadar station construction, the contractor will be using concrete decking and not steel,” added Gupta.
While chequered plates will be used for the decking, the vehicle speed will be restricted to 15 to 25 kmph for the length of the station. After the station construction is completed, the contractors will reinstate the road after surfacing it.
The Metro III connecting Colaba-Bandra-SEEPZ is expected to be completed in two phases. While the stretch from Aarey Milk Colony to the airport is set to be operational by March 2021, the second phase till Cuffe Parade is expected by December 2021.