|
Project Overview:
The HBG Constructors joint venture, with HBG
Flatiron, FCI
North and Interbeton, performed the $120 million
seismic retrofit of the Benicia-Martinez Bridge, one
of five San Francisco Bay Area toll bridges to be seismically
retrofitted.
The retrofit involved strengthening the 10 main spans
(6200 feet) over the Carquinez Strait by replacing the
existing rocker bearings with seismic isolation bearings,
adding new tapered exterior concrete jackets to each
of the piers, adding additional drilled shafts, placing
tie-down anchors through spread footings, and installing
grouted-pipe piles through existing drilled shafts.
Heavily traveled, the bridge originally built in 1962
carries over 100,000 vehicles a day.
As part of the seismic isolation of the Benicia-Martinez
Bridge, the existing rocker bearings were replaced with
friction pendulum bearings. The new bearings will allow
the bridge's substructure to move up to six feet during
an earthquake with minimal displacement of the superstructure.
The seismic isolation bearings used on the project are
the largest friction pendulum bearings ever built, weighing
over 40,000 pounds each. Construction was performed
over water from barges and temporary trestle and cofferdams.
Benicia-Martinez
Project Photos:
Summer
2002
Project Features:
175,000 drilled holes and 1,515 tons of new structural
steel members
34,000 cubic yards of structural concrete to strengthen
existing piers
9,000 drilled, linear feet of 17-inch diameter holes
through existing drilled-shaft foundations and installing
tie-down anchors to install grouted-pipe piles
94,304 feet of high strength reinforcing steel and
5,816 tons of standard reinforcing steel
Existing rocker bearings replaced with friction pendulum
bearings
Project Related Links:
California Department of Transportation
http://www.dot.ca.gov/hq/esc/tollbridge/default.html?Ben-Mar/Ben-Mar.html
back to top
|
