Performance Based Design (PBD) and a system of steel Special Moment Resisting Frames (SMRFs) with Viscous Damping Devices (VDDs) were used for the seismic design of a new multi‐story medical building in California. The five‐story, 132,000 ft2 office building is one of the first structures in the United States to apply 2005 ASCE 7 procedure to design with VDDs. In accordance with ASCE 7, the steel frames were sized and designed with strength requirements of the code level force. VDDs were provided to control displacement of the structure. Earthquake performance and cost effectiveness were the primary concerns in designing this building. Site‐specific response spectra and spectrum‐compatible time histories, synthesized for 500‐year and 2,500‐year return events, were used for nonlinear response history analysis. Comparison analysis of the PBD design and conventional design (CD) showed that the PBD building had superior seismic performance. PBD lead to a long period, low frequency, structure with low acceleration. VDDs reduced the displacement level to less than a 1% story drift ratio. A cost study shows that much of the VDDs expense is offset by decrease in the weight of the steel members and reduction in foundation costs while providing a far superior performance.
