By: Neelam Mathews l Source: enr.construction.com

Fourteen teams are vying for prequalification for the $4.4-billion Mumbai Metro-Line 3 project, which will entail $2.6-billion in civll work, including potentially complex tunneling through coastal and cultural areas of Mumbai.

Afcons-KMB, CEC-ITDCEM-TPL, CTCEG-PIIPL, Dogus-Soma, IL&FS-CR25G, J Kumar-CRTG, L&T-STEC, Mosmetrostroy-HCC, OHL-SKE&C, Pratibha Industries-GDYT, Sacyr CMC ESSAR, Salin Impregilo-Gammon, STRABAG-AG-Patel and Unity-IVRCL-CTG submitted prequalification bids in Februrary. The tender is scheduled for release by July with the contract to be awarded by January 2015, according to Sanjay Sethi, managing director, Mumbai Metro Rail Corp. (MMRC), a fully-owned company of the Mumbai Metropolitan Region Development Authority (MMRDA).

The planned Line 3 is part of master plan prepared by Delhi Metro Rail Corp. (DMRC) assisted by Tata Consultancy Services (TCS) & IIT Mumbai for 450 kilometers of mass transit systems by 2031. The first phase comprising nine corridors of 146.50 km has already started.

Line 3 spans approximately 32.5 km from Colaba in the south into the Special Electronics Export Processing Zone in the north, comprising 26 underground stations. With a water table between 5-7 m deep, “We need to go 22 m deep where there is a hard rock basalt formation. This requires tunnel boring equipment,” says P.R.K. Murthy, chief of transport & communications for MMRDA. Construction of stations will be either cut-and-cover or NATM (New Austrian Tunneling Method) as per site requirements, he adds. For each station, a 270-m-long box will need to be constructed using a top-down approach.

Both natural geology and man-made structures will pose challenges. “A large portion of tunneling is in the older part of the city with heritage structures. We will have to be careful to ensure health of the buildings. This is unlike Delhi with soil where machines bore easily,” says Santosh Rai, head of transportation sales for Hindustan Construction Co. “The geology of the soil will be the biggest challenge for the contractor.” HCC recently won its third contract from DMRC under the Phase III development for design and construction of 1.54-km-long twin tunnels. The company’s extensive water tunneling experience in Mumbai will stand in good stead, says Rai.

Bidders are confident the project will be fast-tracked with a 30-year loan from Japan International Co-operation Agency (JICA) providing 57% of the project cost at a 1.5% interest, not inclusive of currency fluctuations.

Prequalification bids for the fourth line are expected to be announced soon, while the ninth and final line, in another five to six years.

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