Recently, San Francisco passed a mandatory Soft-Story Retrofit Ordinance that will require a seismic retrofit of existing buildings identified as having a soft-story hazard, typically on the first floor. Though not the first city to enact such an ordinance, it is the largest to do so. The ordinance could affect an estimated 3,000 number of buildings in San Francisco, primarily multifamily with mixed-use tenants or parking on the first-floor level.
What is Considered a Soft-Story?
Certain buildings have deficient seismic capacity at the first-floor level (termed a soft- or weak-story)—i.e., they do not perform well during an earthquake due to a lack of seismic strength. Examples of soft-stories include tuck-under parking, glass-front walls, and first floors with a much greater height than on other floors.
Not all soft-stories are seismically deficient; newer buildings built to more modern building codes will perform better during a seismic event. The San Francisco Soft-Story Retrofit Ordinance only applies to buildings built prior to 1978 that have more than five residential apartment units and must be at least three stories tall.
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