Wood-Frame Soft-Story Structures
The city of Oakland does not currently mandate seismic retrofit of wood-frame soft-story buildings, but the city does mandate a screening-style structural evaluation for some structures. In 2008, the municipality did a preliminary survey of multifamily residential buildings. With the results of that survey, Oakland passed a mandatory ordinance in 2009 requiring owners of certain buildings identified in the 2008 survey to undergo a structural screening of the ground floor. The screening was intended to provide the municipality with more information on the construction of the ground floor to determine whether it is considered a wood-frame soft-story building. The full text of the ordinance can be found here.
Oakland’s mandatory screening program applied to existing buildings identified in a 2008 survey that have the following characteristics:
- Wood-frame construction
- Permitted for construction prior to the adoption of the 1988 Uniform Building Code on January 1, 1991
- Five or more dwelling units
- Two or more stories
- Ground floor containing parking or commercial space
The ordinance specifies two levels of evaluation. A Level I screening is defined as a prescriptive, nonengineered analysis that may be written by a registered design professional, a licensed contractor, or a certified inspector. If the building official determines that the conditions of the structure are beyond the scope of the ordinance’s standards, a Level II screening is required. A Level II screening involves a nonprescriptive engineered analysis to be completed by a registered design professional.
All building owners who received a notice from the building official indicating that their building falls within the scope of the 2009 mandatory screening program were required to submit a structural screening to the building official within two years of the day the ordinance was passed on July 28, 2009.
Wiss, Janney, Elstner Associates, Inc.
Oakland Building Services Division
250 Frank H Ogawa Plaza, Oakland, CA 94612