Office Complex

2401 Crow Canyon Rd.

San Ramon, CA


   The existing one-and two-story buildings were constructed primarily of pre-cast concrete, and the building bracing system relied upon the connections between the pre-cast beams and columns. This bracing system did not provide the strength necessary to resist the strong ground motions associated with a large earthquake. Bracing improvements were previously developed by others, but were found to be too costly. 

   The improvements developed by Fratessa Forbes Wong focused on creating strong diaphragms (or plates) at the roof and second floor levels, then providing strong perimeter ties and bracing elements. The strengthening at the floor and roof areas was accomplished by placing glass fiber reinforcing embedded in epoxy. This was supplemented by carbon fiber and steel ties, chords, and collectors. The perimeter bracing consists of concentric braced frames using tube steel members and continuous perimeter plates bolted to existing concrete framing. The goal of seismic improvements was to gain strength and performance consistent with the current building code. 

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