West Anchorage Design of San Francisco - Oakland Bay Bridge Main Span for Seismic Loads

摘要

Located at the rocky edge of the Yerba Buena Island, the west anchorage of the San Francisco - Oakland Bay Bridge suspension span serves as the anchor for this single tower self-anchored suspension bridge. With extensive comparative studies on numerous alternatives, the new looping cable anchorage system is recommended for the final design of the west anchorage of the self-anchored suspension span. The looping cable Anchorage system essentially consists of a prestressed concrete portal frame, a looping anchorage cable, deviation saddles, a jacking saddle, independent tie-down systems, and gravity reinforced concrete foundations. This anchorage system is chosen for its dimensional compactness and structural efficiency as well as reliability under static and seismic loads. This paper describes the major design issues, design philosophy, and key structural elements of this innovative suspension cable anchorage system.