In the news this week, ABC covered the erection of the first suspension tower on the Eastern span of the San Francisco Oakland Bay Bridge. Klohn Crippen Berger (KCB) designed the lifting frame and lifting gantry seen raising the first of the upper four legs of the permanent tower in this feature story. The frame was designed to lift and place each of 16 legs, which measure over 100’ long and weigh up to 1100 tonnes, up to 400’ in the air.
Retained by American Bridge/ Fluor Joint Venture, KCB is providing lead construction engineering services for the Self-Anchored Suspension Span for the San Francisco – Oakland Bay Bridge Seismic Safety Project. In addition to the lifting frame and gantry featured on ABC news, KCB also designed the falsework used to support, maneuver and assemble the 28 orthotropic box girder sections which when assembled form the two 600m long decks. Assembly of the permanent structures began in February 2010 and both tower and deck are now more than 80% complete.
Constructed in 1936 the original San Francisco Bay Bridge, the largest in the world at that time, was considered a marvel of modern engineering. Following the earthquake of 1989, the need for a new bridge that would withstand strong seismic action was established. The new San Francisco-Oakland Bay Bridge, which began construction in 2006, will continue the tradition of engineering excellence with the construction of the signature, record breaking, Self Anchored Suspension Span (SAS). Upon completion of the project (projected for 2013), the San Francisco Oakland Bay Bridge will be the longest single tower self-anchored suspension bridge in the world.