Work Progressing on Foresthill Bridge Seismic Retrofit and Repainting Project
December 26, 2012
Work on the Foresthill Bridge seismic retrofit and repainting project continues with a significant amount of work having being completed. The bridge, first opened in 1973, has never been repainted and is in the
|In an area enclosed in tarps, a painter applies finish coat paint to a section of the Foresthill Bridge.
process of receiving new primer and paint. Additional steel is being added to strengthen the bridge against earthquakes. Federal and state resources have funded the majority of the $70 million project, which began in early 2011.
One major milestone completed has been the complete removal of the original lead-based paint and primer. When the bridge was built, lead-based paint was used to protect the steel from the elements. Steel shot blasted away the paint from the bridge and the hazardous material was captured, pumped into containment barrels and removed from the site. In all, 194,000 pounds of hazardous paint material was removed from the bridge.
To facilitate the paint removal and subsequent application of new paint, the bridge was encased in tarps, a section at a time. The bridge is being repainted in the same green color that has covered it since it was built. To date, nearly 9,000 gallons of paint have been used on the project.
The seismic retrofit of the bridge, when complete, will add over 2.3 million pounds of structural steel throughout the 2,428-foot span. To connect the additional steel, more than 190,000 bolts will be used. To date, 80 percent of the new steel has been added to the bridge.
This is a great project with an excellent project team,” said Sherri Berexa, project manager. “I am very pleased with the work completed to date.”
Concrete anchor blocks were added inside the abutment structures at each end of the bridge. A total of 1,259 cubic yards of concrete have been poured so far. Buckling braces or “sacrificial elements” were installed on the anchors and are designed to allow the bridge move during an earthquake. Once installed, the braces do not require maintenance and are easily replaced.
Modifications are planned for the pier bearings that sit atop the concrete columns rising from the American River Canyon. Pier bearings connect the steel truss to the concrete piers and allow the two piers and truss assemblies to move. A large crane is necessary to complete this work and will be brought onto the north side of the bridge to lift the 31,000-pound steel assemblies over the bridge rails and lower them into place.
|A worker paints primer on newly installed bolts.
When all the bridge work is complete, the open area between the two lanes will be filled. The open center median has already been partially filled to provide additional deck area for construction, while allowing traffic in both directions. One of the last operations is filling in the remaining deck area and raising the pedestrian hand rail on the sidewalk. Completion of the bridge work is expected to be in spring of 2014.