Transportation

Central Subway

A 3.1-mile underground extension of the Market Street subway, delivering twin bored tunnels, three underground stations and a cavern beneath an operating city centre.

Design and construction management support for one of the most technically demanding urban transit projects in North America.

The alignment threads beneath a seismically active, building-occupied corridor, requiring low-vibration tunnelling, groundwater control and continuous settlement monitoring. Our teams delivered excavation support design, shaft and station structures, and construction phase engineering through to handover.

Scope of work

  • Tunnels & Underground Engineering
  • Construction Management
  • Geotechnical Engineering
Central Subway — San Francisco, CA
Central Subway, San Francisco, CA. Hoffman Tunnels provided tunnel and underground design, engineering and construction-phase support.

Project facts

Length
3.1 miles
Tunnels
Twin bored
Stations
3 underground
Completion
2022
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