Skanska USA Civil Northeast, as part of the S3 Tunnel Constructors joint venture with partners J.F. Shea Construction, Inc. and Schiavone Construction Co., Inc., was awarded this $337 million assignment from New York City Transit for Contract I of Phase I for the Second Avenue Subway between 96th Street and 63rd Street in New York City. The team constructed the northbound running tunnels between 72nd and 92nd Streets and the southbound running tunnels between 92nd and 63rd Streets. The project called for construction of three new stations and one station rehabilitation. The joint venture constructed a 400-feet-long by 60-feet-wide “launch box,” which will be the location of the future 96th Street Station. To construct it, approximately 180,000 cubic yards of in-place rock were mined, and approximately 125,000 cubic yards of earth and rock was excavated. Two parallel, two-and-a-half-milelong train tunnel shafts were advanced from that box using a tunnel boring machine (TBM). Additionally, two access shafts were installed for the future 72nd Street Station. Part of the soil and rock that was excavated was found to be contaminated and had to be treated in an environmentally sensitive manner. Also included in the contract were temporary road decking and an electricity substation. One of the most challenging aspects of Phase I of Contract I was the relocation, replacement and support of a myriad of utilities (including electric, gas, sewer, water, telephone, and communications) while maintaining four lanes of traffic through the work site. The Second Avenue Subway is a new subway line that residents of New York City have anticipated for decades. When completed, two tracks will run along the line from 124th Street to lower Manhattan, with a connection to West Midtown and Brooklyn. The Transit Agency hopes to improve congestion and commute times on the over crowded Lexington Avenue (No. 6) line.
