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Central Subway

Preliminary and final SEM tunnel design at Chinatown Station.
Estimated cost: Commencement:
March 01, 2010
Completion date:
May 01, 2012
425 Market Street Suite 1700
San Francisco, CA 94105
United States
Technical data:
Geology description:

The geology ranges from soft clay (Bay Clay) to stiff sands (Colma Sands) and competent to highly fractured rock (Franciscan Formation). A considerable part of the tunnel alignment is below the groundwater table.

Bid cost: Final cost:
$1.6 billion USD
Service areas:
Tunneling under:

MUNI planned a 2.7 km underground extension to the Third Street Light Rail Project. The underground section would start near Bryant Street, run along Third Street, cross under four BART Tunnels at Market Street and continue under Geary and Stockton Streets to Clay Street. Dr.Sauer and Partners was the designer for the SEM Tunnel Structures at Chinatown Station and prepared detailed excavation and support sequences as well as procedures for the construction of the large caverns and final design documents for SEM construction.

Route map
Overall station layout, headhouse and caverns (Rendering by JV)