Proposals will be accepted Feb. 14 for replacement of the historic Point Bonita Lighthouse Suspension Pedestrian Bridge—a project that will include lead handling and coatings application.
The site, owned by the U.S. Coast Guard and maintained by the National Park Service, is located within the Golden Gate National Recreation Area near San Francisco.
The project is being administered by the Federal Highway Administration. FHWA chose a Construction Manager/General Contractor (CM/GC) contract structure to encourage the federal agencies, consultant and contractor to partner on completing and executing the design. The design is about 30% complete.
The CM/GC firm will play an important role in keeping the project under budget, by applying its expertise to scheduling and project logistics and by proposing beneficial innovations, project officials said.
Specs and Plans
The three-span, two-hinged, 244-foot suspension bridge will be replaced with a similar model constructed of tropical hardwoods and metal cables. The project includes coating new bridge surfaces, as well as handling and disposing of lead-based paint on the existing structure.
The new structure will also employ a two-hinged suspension bridge design, including the asymmetrical straight backstays. The new design will be limited by the restrictions of the site’s geography, which was accommodated in the existing bridge with a 156-foot main span flanked by a 55-foot approach span on the west and a 33-foot approach on the east.
Access, Power Constraints
Access to the bridge site is very restricted. The only land access is along a steep, ½-mile long trail that goes through a tunnel that is about 6 feet tall and 4 feet wide. Helicopter operations will probably be required to transport equipment and materials to the bridge construction site.
Access to the Lighthouse side of the bridge will have to be provided even after the existing bridge is demolished and removed. The Coast Guard requires 24-hour access to the lighthouse every day. Electric lines cross the existing bridge to provide power for the Lighthouse. The contractor will need to maintain electrical power even after the existing bridge is demolished and removed.
Point Bonita Lighthouse, first lit in 1855, is the only American lighthouse to be reached by a suspension bridge. The lighthouse bridge, which was built in 1954, is modeled after the Golden Gate Bridge.
The bridge underwent a major rehabilitation in 1979, followed by repainting in 1998. A 2007 inspection concluded that deterioration of the coating system had resulted in an accelerated rate of corrosion on the cables and associated hardware. The continued corrosion has led to section loss that, coupled with increasing decay of the timber elements, closed the bridge in July 2010.
Reported by Paint BidTracker, a construction reporting service devoted to identifying contracting opportunities for the coatings community.