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Dumbarton-Bridge

Bidder's Conference and Networking Event Dumbarton Bridge Seismic Retrofit Project May 6, 2010 Dumbarton BACKGROUND

The Dumbarton Bridge was completed in 1982. It connects the City of Fremont on the eastern side of the San Francisco Bay to the borders of the Cities of Menlo Park, and East Palo Alto on the western side. The bridge provides access for approximately 61,000 trips across the bridge between Alameda and San Mateo County each day. It spans 8,600 feet accommodating three lanes of traffic in each direction. The five main components of the bridge include: A Main Channel crossing at the middle of the bridge, an Approach Structure at each end of the main crossing, and a Trestle Structure at the end of each Approach Structure.

SEISMIC RETROFIT STRATEGY

The Dumbarton Bridge will be strengthened to withstand a Maximum Credible Earthquake (MCE). The final retrofit design consists of the following major activities:
  • Strengthen the existing slab bridge frames with fourteen – 4ft diameter steel pipe piles on north and south sides of selected trestle bents, both east and west trestle structures (total 28).
  • Remove , modify, and replace existing concrete curtain wall panels.
  • Replace existing deck joints with seismic joint system to accommodate increased joint movements at Piers 1 and 44.
  • Retrofit the east and west approaches by strengthening pile cap to column connections, bent cap to superstructure connections, and superstructure to meet flexural demands at Piers 10 through 15 and Piers 32 through 37, and existing columns to receive concrete jackets at Piers 5 through 16 and Piers 31 through 40.
  • Retrofit the main channel between Piers 16 through 31; strengthen pile caps, column to bent cap connections for joint shear. In addition, strengthening existing steel box superstructure cross frames at Piers 18 through Pier 31, replace the existing TFE/Elastomeric bearings with isolation bearings (6 each), and modify existing hinges with seismic isolation joints at Piers 16 and 31 to accommodate large seismic movements.
  • Install a barrier on the east end of the bridge (north side) to prevent tidal impacts to the parking lot during construction. The barrier would retain the bay water that encroaches from the Moseley Tract and thus prevent damage or access problems during the project. The barrier will be placed along the paved shoulder within the State’s R/W.
  • Construct a pumphouse with a maximum footprint of 10 ft by 10 ft to discharge all bridge and parking lot surface water through a 12” to 18” diameter outflow pipe up and over the existing levee.
  • Remove the existing Ravenswood Pier on the west side.
  • Repave the existing access roads and parking lots on the east and west approaches.
All work will be within the existing right of way. Most of the proposed work will be carried out during the nighttime and weekends to minimize traffic delay and congestion on this heavily traveled freeway corridor. For details on proposed works, see the Attached PSSR.

ENVIRONMENTAL ISSUES

The CEQA and the NEPA documents have already been approved for this project. Approval must be obtained from: US Army Corps of Engineers, NOAA, BCDC, Regional Water Pollution Prevention Program, SWPPP, and US Fish & Wildlife Service.


SCHEDULE

MILESTONE: DATE:
Advertise Date March 31, 2009
Approve Contract August 2010
Construction Contract Acceptance April 2013
Dumbarton Map