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Sunnydale Auxiliary Sewer

Location: San Francisco, CA
Owner: San Francisco Public Utility Commission
Completed: February 2012

The Sunnydale Auxiliary Sewer Project was a complex tunnel project which employed numerous construction methods to address various project specifics.  The project included the installation of 75 lineal feet of 104” pipe constructed by jet grouting and hand mining, 180 lineal feet of 104” pipe constructed by interlocked steel sheeting cut-and-cover method; 3,070 lineal feet of 144” I.D. precast segmented tunnel constructed by 168” OD EPB TBM, and 2,050 lineal feet of 85” pipe constructed by MTBM microtunneling. The project required the installation of five launching/receiving shafts each with manhole structures to tie into the existing sewer system. The project included many design and construction challenges including an assortment of ground conditions, and various overlying urban infrastructure.  This project was completed on time, on budget, and received numerous awards including the ASCE Region 9 “Outstanding Collection System Project Award” for 2012.