The City of Los Angeles recently passed Ordinance 183893, which requires the retrofit of pre-1978 wood-frame soft-story buildings and non-ductile concrete buildings. The goal of the mandatory retrofit programs, under the ordinance, is to reduce these structural deficiencies and improve the performance of these buildings during earthquakes. Without proper strengthening, these vulnerable buildings may be subjected to structural failure during and/or after an earthquake
Soft-Story Retrofit Program
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.
Non-ductile Concrete Retrofit Program
During the earthquakes at Northridge, Mexico City, and most recently, Christchurch New Zealand, many concrete buildings constructed prior to the 1976 Los Angeles City Building Code provisions, or similar era codes in other countries, performed poorly and collapsed, causing loss of human life, personal injury, and property damage. The poor performance of these older concrete buildings is due to deficiencies in the lateral force-resisting system that render the building incapable of sustaining gravity loads when the building is subjected to an earthquake.
Buildings that are within the scope of this ordinance and require retrofitting are concrete buildings with a roof and/or floor supported by a concrete wall or concrete column, constructed before January 13, 1977.
The property owner must comply with the ordinance within the following time limits:
From the receipt of the Order to Comply:
- 3 years: Submit completed checklist for review to determine if building is a non-ductile concrete building
- 10 years: Submit proof of previous retrofit, or plans to retrofit or plans to demolish building
- 25 years: Complete construction
LADBS is currently in the process of identifying the concrete buildings subject to the retrofit ordinance.
Any concrete building, as defined in the retrofit ordinance, and built pursuant to a permit application for a new building that was submitted before January 13, 1977 is subject to the retrofit ordinance whether the building has been identified by LADBS or not.