Seismic retrofit design for a soft-story residence in San Francisco, CA

There is a current and pressing need to retrofit hundreds of soft story buildings in the city of San Francisco, CA, that have the potential to collapse in the next big earthquake. The soft story condition, which means that the ground floor of the building is significantly weaker and less stiff than the floors above, is widespread in the city. As a result, the City of San Francisco has mandated through a city ordinance that all of these buildings be retrofitted by the year 2020. The project team addressed this problem by designing a retrofit for a soft story residential building located at 33 Guerrero Street in the Mission District of San Francisco. The team proposes the installation of two new cross-laminated timber shear walls with the appropriate concrete foundation and hold down. The team also proposes to enhance the existing timber shear walls by adding blocking between panel edges and standard hold downs with the appropriate concrete footings. To encourage implementation of the design by the building owner, cost was minimized and ease of construction was highly considered