An immense, barge-mounted crane dubbed the “Left Coast Lifter” that will be used to help build the San Francisco-Oakland Bay Bridge’s new suspension span passed under the Golden Gate and into San Francisco Bay just after 2 p.m. today. The 400-foot-long barge – built by U.S. Barge in Portland, Oregon – was shipped to China in April 2008 for fitting by Shanghai Zhenhua Port Machinery Co. Ltd. (ZPMC) with a custom-built shear-leg crane capable of lifting up to 1,873 tons. Today marks the end of the barge's second trans-Pacific crossing.
The replacement of the East Span of the San Francisco-Oakland Bay Bridge is one of the largest public works projects in California history, and requires the use of some of the biggest construction equipment that exists. And the “Left Coast Lifter” is no exception, weighing in at a whopping 3,920 tons. The extended boom of the shear leg crane is 328 feet long, and will tower above both the cantilever bridge and the new Skyway decks when raised.
The “Left Coast Lifter” will be used starting this summer to offload and erect the steel used in the temporary support structures for the new signature span, as well as to raise all 28 deck segments of the new span’s roadway and the lower sections of its steel tower. The upper reaches of the 525-foot tower are beyond the reach of the crane’s boom, so a strand jack system built into the tower’s temporary frame will lift those pieces into place.
During its month-long trans-Pacific crossing, the self-erecting crane was laid down and stowed for transport, and the entire crane barge placed on a special semi-submersible ship. When the ship gets to its mooring site south of the Bay Bridge, it will partially submerge, allowing the barge to float while the ship slides out from underneath it. The barge will then move to a pier in the Port of Oakland, where it will be prepared for service. Later this spring, the fully operational crane will sit north of the new East Span construction site near Yerba Buena Island, in view of motorists driving over the Bay Bridge.
The new East Span is two bridges in one: a sleek Skyway (with side-by-side roadways) that is already complete, and a self-anchored suspension span, or SAS, closing the gap between the end of the Skyway and Yerba Buena Island. The East Span project is being directed by the Toll Bridge Program Oversight Committee, a consortium of three agencies: Caltrans, the California Transportation Commission and the MTC-run Bay Area Toll Authority (BATA). BATA is financing the project with bridge toll funding. For more information about the project, go to baybridge360.org and baybridgeinfo.org.