As part of the replacement the Eastern Span of the San Francisco-Oakland Bay Bridge, a temporary road structure was built on Yerba Buena Island to provide a traffic detour during construction. The transition from the old bridge to the temporary “S-Curve” detour took place over the 2009 Labor Day weekend when a 200-ft portion of the old double-deck bridge section weighing 3,200-tons was cut and rolled out of the way and a new section weighing 3,600-tons was rolled into position. Due to the massive weights of both the old and new bridge sections, multiple towers and skid beams had to be erected to support the double-deck structures at a height of 150 feet.

Following the transition to the new detour structure, Sheedy was contracted to remove the girders and towers that had supported the old and new bridge sections. To complete the task, Sheedy mobilized a combination of conventional crawler cranes, hydraulic truck cranes and rigging crews from its yard in San Francisco.

The skid beams, each weighing 600,000-lbs., were jack and rolled by Sheedy’s riggers, cut up, and then hoisted down to the ground in sections. The tower sections were then similarly disassembled and removed. The largest piece of steel to be hoisted by a single crane weighed 260,000 lbs. using Sheedy’s Manitowoc M-250 300-ton crawler crane. Several other two-crane picks were performed using the M-250 in conjunction with Sheedy’s Manitowoc 888 225-ton crawler crane. Each of these pieces weighed 250,000 lbs. at a heigh of 150-ft. A 70-ton hydraulic rough terrain crane assisted in hoisting the rigging crew aloft in a manbasket while Sheedy’s 200-ton hydraulic all terrain crane assisted in the dismantling part of the old bridge that had been erected in the late 1930s.

Besides the difficulties of handling the massive deck assemblies, some of the additional challenges faced by Sheedy included limited site access and uneven terrain. Thus, coordination by Sheedy’s staff engineer, Mercury Manns, with the general contractor, other subcontractors and the owner, Caltrans, was key to making this a successful project.

Photos by
Bill Cendak II
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