The San Francisco Municipal Transportation Agency in California is ramping up construction of the Central Subway with major work to prepare for tunneling, including excavation of almost an entire city block.
This new stage of construction will be the first to build permanent elements of the Central Subway, kicking off the next phase of progress on this transit project.
On June 12, tunneling contractor Barnard Impregilo Healy Joint Venture will begin excavating and constructing a launch box at the site where tunneling will begin. The launch box will be built on 4th Street between Bryant and Harrison streets, beneath the I-80 overpass. At nearly 500 feet long, 50 feet wide and up to 40 feet deep, this major excavation will take up most of the block. Next year, a pair of tunnel boring machines will start digging the Central Subway tunnels from the launch box, traveling north under 4th Street and then Stockton Street.
This year, tunnel preparatory work will also take place at several other locations along the project alignment. In addition to the launch box, the tunneling contractor will construct below-ground walls at two subway station sites, relocate utilities and perform ground-stabilization work to prepare for construction of the Central Subway tunnel.
Work to prepare for headwall installation, including potholing and utility relocation, will begin on 4th Street between Folsom and Howard streets, at the site of the future Yerba Buena/Moscone Station. Headwall installation will follow. The walls will be constructed across 4th Street and reach a depth of about 100 feet.
In other news, SFMTA appointed Vince Harris as director of capital programs and construction. Harris, previously the executive director of the Stanislaus Council of Governments (StanCOG) in Modesto, Calif., and the executive director (1988-1998) of the Alameda County Transportation Authority will take over the position effective June 11.
Harris will be responsible for the SFMTA’s $3 billion Capital Improvement Program, including new light-rail extensions, facility upgrades and enhancements and system overhead wire and rail replacement projects. His division will include capital engineering, project management, project controls, construction management, contract administration and capital quality assurance functions.