Answer:From past earthquakes, multi-story buildings with weak and/or open front wall lines creating a “soft-story” (i.e. buildings with tuck-under-parking) performed poorly and collapsed. The goal of the mandatory retrofit program, under Ordinance 183893 and Ordinance 184081, is to reduce structural deficiencies by the most economical and feasible method. Without proper strengthening, these vulnerable buildings may be subjected to structural failure during and/or after an earthquake.
Buildings that are most vulnerable have been identified with the following criteria:
Consist of 2 or more stories wood frame construction
Built under building code standards enacted before January 1, 1978
Contains ground floor parking or other similar open floor space
The program does not apply to residential buildings with 3 or less units.