Namma Metro invite tender for Design & Construction of Underground structures

14 km of Gottigere-Nagawara line to go underground in city’s heart

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Namma Metro
Namma Metro

Bengaluru, Metro Rail News: The “practical difficulties” of constructing an elevated Metro corridor on narrow roads have prompted the Bangalore Metro Rail Corporation (BMRCL) to stick to its original plan of building a 14-km underground stretch through the heart of Bengaluru. With the change in plan, 

the Gottigere Nagawara line will go underground from Dairy Circle to Nagawara. The section is referred to as Reach 6 of Phase II.

On January 21, 2019, Namma Metro floated bids for construction of two portions of the underground stretch of Reach 6 — a 3.65-km stretch between Dairy Circle and Vellara Junction and a 4.59-km stretch between Tannery Road and Nagawara. Bids for the seven-km underground stretch between Vellara Junction and Tannery Road were floated in two packages last year and are likely to be awarded in a week’s time. “We have stuck to the original plan of building the underground stretch due to multiple reasons. Even though it’s technically feasible to build an elevated corridor, there would have been practical difficulties,” Ajay Seth, managing director of BMRCL.

A senior official said the plan to have an elevated stretch on Tannery Road was dropped due to challenges in land acquisition. “The stretch is a thickly populated residential area. More than the cost component, acquiring land would have created social problems such as displacement of people and establishments,” he said. The BBMP, he said, had initially planned to widen Tannery Road but there has been no progress in a year.

The detailed project report of Phase II also suggested going underground between Dairy Circle and Nagawara to minimise land acquisition issue. The transport utility was, however, in two minds. BMRCL had planned to have the 14-km stretch partly elevated. This was after four construction companies — in the first bid for underground works — quoted about 69% more than Metro’sestimate.

To avoid what the BMRCL suspected to be a collusion of contractors, it chose to invite bids only for two packages (Vellara Junction-Shivajinagar and Cantonment-Pottery Road) in July 2018. It kept two other packages on hold. There was a strong suspicion of collusion as the four construction companies had emerged lowest bidders in each of the packages of the UG section, which was split into four.

TWO REMAINING PACKAGES

For the two remaining packages, BMRCL has revised the length and cost. While Namma Metro’s estimate and length of the tunnel remains the same in Package 1 as with the previous bid, there have been some changes in Package 4.

Senior officials said the length of the underground portion in Package 4 is kept longer than Package 1 due to geological conditions. “Our studies show that the underground stretch between Vellara Junction and Pottery Road comprises mixed geology, including hard rock, while the stretch between Tannery Road and Nagawara is smooth,” he said. Each eligible construction company, the officer said, will have to deploy a minimum of two tunnel-boring machines to carry out work on each package


13th International Railway Equipment Exhibition (IREE) 2019

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