San Francisco Public Utilities Commission - Bay Tunnel - Ravenswood Portal

We have been contracted to assist with the underwater construction of a launch portal for the new Bay Tunnel. Diving is being conducted to depths of 130 fsw in zero visibility. The crews are installing rebar dowels, rebar mats, and assisting with the tremmie pour of a ten foot thick concrete floor. After the tremmie pour is complete the shaft will be de-watered in preparation for the tunnel construction. Upon completion of the shaft the horizontal tunnel under San Francisco Bay will be drilled with a Tunnel Boring Machine.