Plaza 555 is in Sacramento and consists of two non-ductile 14-story reinforced concrete frame buildings originally constructed in the 1970s. The owner, Pac West Office Equities, hired Miyamoto International Structural and Earthquake Engineers to retrofit the buildings.
The engineers at Miyamoto used SP3-Design (now SP3-RiskModel Advanced) to iteratively design their retrofit solution; they selected Taylor viscous dampers as part of their retrofit and were able to reduce expected losses to only 12% for a 10%-in-50-year ground motion.