Earthquake Hazard Reduction & Soft Story Buildings:

The City of Richmond Planning & Building Services Department is preparing an inventory of multi-story buildings that may not have sufficient ground floor strength to support their upper floors during a major earthquake. Buildings that have this condition are classified as having a “soft story” (If a building has a floor that is 70% less stiff than the floor above it, it is considered a soft story building). Upper floors that rest on insufficient structural support on the ground floor can be especially vulnerable because they cannot withstand the lateral forces caused by swaying during seismic events.

Soft story buildings often have lots of open space on the ground floor; this condition can be found in apartment buildings that were originally constructed over parking areas and garages or ground floor commercial spaces. Soft stories in pre-WWII buildings are often wood stud or stick construction braced by diagonal board sheeting. However; some soft story structures (often constructed between 1960 and 1980) rest on steel posts and wooden beams. By installing additional bracing on the ground floor, property owners can substantially reduce the likelihood of experiencing a catastrophic collapse of the building.

The purpose of the inventory is to identify potential soft-story buildings and to alert property owners about the potential risk of damage and loss that could occur during an earthquake. Establishment of an inventory is a required first step for property owners who seek outside funding to retrofit their buildings.

Visit Richmond’s Building Division webpage at http://www.ci.richmond.ca.us/building. It contains web links that provide additional information about earthquake hazard reduction.

This special was recorded on August 31, 2011.

The agenda:

1. Welcome and Introductions by Kieron Slaughter, City of Richmond

2. Description of Soft Story Buildings, Hazards, Etc. by Kieron Slaughter, City of Richmond

3. Explanation of the City's Position, Outreach Efforts by Richard Mitchell, City of Richmond

4. Seismic Retrofit Case Study by Sasha Itsekson, Enginious Structures

5. Building Code Compliance by Chris Castanchoa & Gautam Manandhar, City of Richmond

6. Regional & National Efforts to Retrofit Soft Story Buildings by Danielle Hutchings, ABAG

7. Wrap Up and Next Steps by Richard Mitchell, City of Richmond