What is a Soft-Story building?
A soft-story condition exists when a building, typically an apartment complex, has openings in the first floor perimeter walls, such as tuck-under parking, subterranean parking or an open storefront. Under these conditions, the first floor is unable to support the weight of the floors above during an earthquake.
What is a soft-story retrofit?
A soft-story seismic retrofit involves:
- Pouring new concrete footings and installing a drag line
- Installing steel moment frame(s)
- Installing continuity ties
- Reinforcing areas around the structure with plywood shear walls
- Removal and replacement of siding materials such as stucco or wood to match existing finish
What is the Mandatory Soft-Story Retrofit Program?
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.
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 fewer units.
|Priority||Categories||Start date of Sending Out Orders|
|I. Buildings with 16 or more dwelling units||3-story and above||May 2, 2016|
|2-story||July 22, 2016|
|II. Buildings with 3 or more stories||with less than 16 units||Oct 17, 2016|
|III. Buildings not falling within the definition of Priority I or II||with 9-15 units||TBD|
|with 7-8 units||TBD|
|with 4-6 units||TBD|
The property owner must comply with the ordinance within the following time limits:
From the receipt of the Order to Comply:
- 2 years: Submit proof of previous retrofit, or plans to retrofit or demolish
- 3.5 years: Obtain permit to start construction or demolition
- 7 years: Complete construction