A cost-efficient concealed bracing system delivers exceptional performance while preserving the historic fabric of this iconic structure.
For this historic structure, the design-and-construction team was challenged to satisfy UC Berkeley Capital Projects' construction budget, the Seismic Review Committee’s performance requirements, and a construction schedule built around the seasonal needs of CalPerformances as well as the University’s commencement ceremonies.
The seismic retrofit design was a scheme completely hidden within the voids of the colonnade structure, in keeping with the requirements to protect the historic fabric. In order to minimize constructability risks, the team conducted an extensive investigation of the existing structure. This included prototype coring of one of the columns within the colonnade. Further, we worked with Vila Construction to document the process and speed of coring to ensure that the proposed design was suitable and reasonable in terms of constructability risks, and developed a design approach covering seismic building improvements and upgrades to the existing life-safety, mechanical, electrical, plumbing, and exit/access systems.
During the investigation phase, we had developed an array of seismic retrofit concepts for the theater, which had been rated “very poor” in the University’s SAFER rating system. Using online design collaboration tools, we refined retrofit concepts with real-time input from University personnel and historic preservation specialists and selected two concepts for further study. Creation of three-dimensional models in Google SketchUp helped assess the visual impact of an exposed retrofit and helped identify constructability challenges for a completely concealed retrofit. Our work also included a review of historic documents from University archives, structural observations on site, a nonlinear response analysis, production of an illustrated report targeted toward University decision-makers, and support in construction cost estimation.
Executed as Tipping Mar
2014 SEAONC Excellence in Structural Engineering, Award of Merit, Historic Preservation
2013 California Preservation Foundation's Preservation Design Award, Preservation Technology and Craftsmanship
2013 SEAOC Excellence in Structural Engineering, Award of Excellence: Historic Preservation
2013 NCSEA Excellence in Structural Engineering, Award of Excellence: Renovation/Retrofit Structures
2012 Engineering News Record, California's Best Projects, Award of Merit, Renovation/Restoration