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Foresthill Bridge Seismic Retrofit and Repainting Project Photo Essay

November 07, 2011

Working on the Foresthill Bridge
Working on the Foresthill Bridge
Initial work on the project was to install two work platforms, one below the roadway and the other under the structural steel arches. First, cables that run the length of the bridge were installed for the upper platform. The lower platform rests on beams that run the width of the bridge. After the support mechanism is installed, the platform is attached and provides a work surface for the iron workers. In the photos top right, top left and the photo at the left and below left,, iron workers install the support beams for the lower platform. In the photo to the right, the upper platform surface in connected to the cables. 
Working on the Foresthill Bridge
Working on the Foresthill Bridge
After installation of the upper work platform, the lower platform is then installed. In the photo to the right, the upper platform is visible at the top, while iron workers install the lower platform,
A view of the bridge, left, with both platforms installed.
Two iron workers, right, bolt a replacement steel plate to the bridge structure
Workers install steel bolts
Detail photo of bolts used in seismic retrofit of rForesthill Bridge
Part of the strengthening of the bridge is installing additional, and in some cases, stronger bolts and more structural steel. These two photos, above, and above right, show the same support piece before and after installation of new bolts.   
Worklers install a piece of structural steel
Iron workers move a steel plate into place, above right, and install bolts with a power tool, right.

The cross brace at the left was installed for support while other, existing parts of the bridge are disassembled piece by piece and then reassembled with stronger components.
Workers install steel bolts
Part of the work being done on the bridge is to improve the performance of the bridge during a seismic event. In the photo to the left, steel cables, called tendons, are installed to strengthen the bridge. The photo above shows the tendons after being tensioned and trimmed.
To prevent old paint and fresh primer from escaping, the bridge is covered with a tent. In the photo above, iron workers install the tenting underneath steel I-beams.
The view of the work area within the tenting, left.

The photo to the right is an external view of the installed tenting.
Iron workers, at left, maneuver a moving scaffolding that is used during paint removal and priming. Below, a tear in the tenting material was caused by winds. The hole was repaired before work began.
A tear in the tentin that is used to capture old paint that is removed from the bridge
A tear in the tentin that is used to capture old paint that is removed from the bridge
The length of the bridge shows three sections that are tented for painting. The entire bridge will be stripped of old paint, primed and then painted, section by section.
The orange apparatus and the black tubing in the photos to the right, the left and lower left is used to remove the old paint. An abrasive steel shot is blasted at the paint and then suctioned out of the work area. The mixture of paint and shot is then separated and the shot is reused. The old paint is transferred to drums and removed from the site.
Iron workers, right, prep the open area between the east and west-bound lanes. This area was then made into roadway. 
The photo at the right shows a jackhammer breaking up the center barrier. In the photo at the left, the once-open center median with reinforced steel installed before concrete was poured.
In the photo to the left, iron workers are seen on the lower platform from the catwalk above.
Iron workers, left, stand on the catwalk beneath the upper work platform.
Iron workers, right, from Golden State Bridge, the project contractor, pose for a group photo. 

All Photos by Sherri Berexa,
Placer County Department of Public works