First transition span of new San Francisco Oakland Bay Bridge lifted into place
By D.Ann Shiffler25 April 2008
The first transition span of the new San Francisco Oakland Bay Bridge in California, US has been lifted into place using computer- controlled Hydrospex strand jacks from Bigge Crane & Rigging.
Bigge said it engineered the lift for the 1,810 tonne steel span off a barge to a height of approximately 60 m within a tolerance of 0.8 mm.
On the Oakland (eastern) side where the skyway bridge deck had already been constructed, the strand jacks were mounted on a mobile jacking platform supported by a pair of 18 m girders, cantilevered 8.5 m off the bridge deck.
On the San Francisco side (west), Bigge used two girders that spanned 38 m across the top of the lifting tower, and strand jacks were mounted on top of a mobile jacking platform on the girders.
At the Oakland end Bigge used four 331 tonne capacity strand jacks, each pulling bundles of 31 strands. At the San Francisco end six 213 tonne capacity jacks were used.
Bigge was also contracted to load the transition spans, or tubs, onto a barge at Portland Oregon, and ship them to the site.
The first one was loaded onto a barge in late December using 48 axle lines of Scheuerle self-propelled hydraulic modular transporter (SPMT).
The barge was then towed out of the mouth of the Columbia River to the Pacific Ocean where it travelled to San Francisco Bay.