myGeobrugg
Situation
In 1954, the U.S. Coast Guard built a suspension footbridge to access the Point Bonita Lighthouse on the outer northwestern point overlooking the Pacific Ocean and San Francisco Bay. Over the years, the bridge had been renovated, but needed to be replaced in 2012. Before a new bridge could be constructed, the rock face needed to be stabilized. The point’s rock mass was fracturing and displaying signs of instability due to years of exposure to harsh marine elements. Stabilization was required to support the weight of a modern bridge without fracturing further.
Description
A stainless steel anchored SPIDER S4-230 mesh system was installed to stabilize the rock face. The diamond shaped net is comprised of three 4 mm wires twisted into a 1x3 strand, with tensile strength of 239 ksi and a diameter of 5/16 inches. As required by the National Park Service, the net was powder coated bronze to better blend with the natural color of the rock mass and further protect against corrosion.
The project won ENR California’s Best Small Project — Construction award in 2012.
Customer
National Park Service
Contractor
AIS Construction (defunct)
Protected object
Building, Touristic infrastructure
Corrosion protection
GEOBRUGG SUPERCOATING + PET, INOX / STAINLESS
Engineering
HDR, Inc.
Subcontractor
Yeh and Associates, Inc.
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