The property at 555 Capitol Mall consists of several structures connected by a 14-story core tower. In the final days of escrow during the property sale, the South Napa Earthquake occurred, shaking the two office towers and causing significant damage to the upper floors. Coincident to this occurring, the lenders notified the owners that they would be required to maintain earthquake insurance on the property in order to secure the loan. We identified the primary vulnerabilities for the two 1970s-era concrete towers to be soft-story ground floors, non-ductile detailing at the frame columns and two instances of captured columns. The improvements included adding eight viscous dampers at the ground floor of each tower, providing fiber reinforced polymer composite wrap at some ground- and second-floor columns, and providing a gap around the captured columns in order to ensure a more regular, uniform response to earthquakes. The retrofit cost was about $800,000 per building and resulted in a savings of $144,000 a year in earthquake insurance.
Location
Sacramento, CA
Year
2014-18
Client
New Legacy 555
PacWest Office Equities
Construction Cost
$1.6 Million
Scale
195,000 x 2 =
350,000 SF
