Northshore Outfall Tunnel Consolidation Contract



Facility Type
San Francisco, CA
Start Date
End Date




Contract N-1: 12' bore, 9' id X 4,152' wet, mixed face sewer tunnel, excavated with open face shield and roadheader-type excavator. Primary support with steel rings & wood lagging; cast-in-place lining.  Shaft 20' sq X 50' deep in sand; support by sheet piles, then CIP liner. Soil is Bay Mud, under Fishermans Wharf.


Contract N-2: 12' bore, 9' id X 3,350' wet, soft ground sewer tunnel excavated with an earth pressure balance (EPB) shield. Primary support with gasketed steel plate, final lining cast-in-place concrete.  Shaft lined with sheet piling, final lining cast-in-place. Soil is Bay Mud. Alignment is under Fishermans Wharf.





OTHER PROJECT (By OBAYASHI CORP. - North American Civil -)