Project Contractor: CalTrans
Clients: Tutor Saliba Corp, American Bridge / Fluor Enterprises, M C M Construction, Inc. C C Myers, Inc. Flatiron West, Inc. Kiewit / Manson, A Joint Venture
Project Date: 2006 - 2018
Description: In the late 1990s, seismic concerns forced CalTrans (California Department of Transportation) to evaluate whether the eastern span of the San Francisco–Oakland Bay Bridge should be retrofited or replaced. After extensive engineering and economic analysis, CalTrans decided that the seismically unsound eastern portion of the Bay Bridge would be replaced with a new self-anchored suspension bridge and a pair of viaducts. To date, the eastern span replacement is the most expensive public works project in California history, and, comprising of 10 general-purpose lanes, it is currently the world’s widest bridge.
Municon provided documentation and instrumentation services from 2006 to 2018 under eight separate contracts on this exciting landmark project. Municon performed work on over ten portions of the $6.5-billion new Bay Bridge and causeway, including the temporary ramp realignments at the Yerba Buena Tunnel and new ramps to Yerba Buena Island and Treasure Island.
The construction of the West Approach was a complex 5-year phase of work that involved the construction of temporary ramps and the re-routing of approach ramps to allow for demolition and construction of the new bridge. For this portion of the work, Municon provided pre- and post- construction photo and video documentation of over 120 buildings, including a few buildings as close as 6 ft to the work. Municon also conducted vibration monitoring of structures adjacent to the construction with up to 19 seismographs deployed at one time.
Municon also provided sound monitoring at the U.S. Coast Guard Station on Yerba Buena Island to record the noise levels generated by work on the Yerba Buena Island Transition Structure – especially noise generated by night time work.
Due to concerns of danger to marine wildlife, Municon provided water-borne vibration monitoring during the East Span Test Pile Project. Municon utilized ultra-sensitive hydrophones to monitor pile driving induced vibrations in the water column at eleven locations from buoyed dinghies. We also used ultra-high frequency velocimeters at multiple locations in the benthic sediments. We operated the hydrophones and velocimeters using customized high frequency digitizing data loggers. The contractor used a Menck 1700 kJ hammer which generated impact energies equivalent to a pound of high explosive per stroke.
Municon also provided pre- and post-construction photo and video documentation, as well as vibration monitoring before and during dismantling of the old bridge foundations.