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Seismic Retrofitting

D.W. Hamilton Construction Inc. has been a leader in quality Bay Area construction since 1982. We are proud to be involved in San Francisco's Bay Area Soft Story Retrofit Program. B.A.S.S. Seismic Retrofit, a singularly focused division of D.W. Hamilton Construction Inc., has been created to provide retrofitting solutions for all of your seismic strengthening needs. Our team of experienced professionals are enthusiastic to be involved in this extremely important work and are dedicated to providing the absolute best in customer service and quality workmanship. Please click Request an Estimate to begin the process of seismically strengthening your properties.

Bay Area Soft Story Retrofit Program

"A soft story building is a multi-story building in which one or more floors have windows, wide doors, large unobstructed commercial spaces, or other openings in places where a shear wall would normally be required for stability as a matter of earthquake engineering design. A typical soft story building is an apartment building of three or more stories located over a ground level with large openings, such as sparking garage or series of retail businesses with large windows. 

Buildings are classified as having a "soft story" if that level is less than 70% as stiff as the floor immediately above it, or less than 80% as stiff as the average stiffness of the three floors above it. Soft story buildings are vulnerable to collapse in a moderate to severe earthquakes in a phenomenon known as "soft story collapse". The inadequately-braced level is relatively less resistant than surrounding floors to lateral earthquake motion, so a disproportionate amount of the building's overall side-to-side drift is focused on that floor. Subject to disproportionate lateral stress, and less able to withstand the stress, the floor becomes a weak point that may suffer structural damage or complete failure, which in turn results in the collapse of the entire building." - Wikipedia

The Mandatory Soft Story Retrofit Ordinance, will require the retrofit of all San Francisco buildings that meet ALL of the following criteria:

  • Wood frame construction (Type V), and
  • Application of permit for original construction was prior to January 1, 1978, and
  • Five or more residential units, and
  • Two or more stories over a basement or underfloor area that has any portion extending above grade
  • A soft story condition that has not been seismically strengthened to the standards set forth in the ordinance.

The ordinance was signed into law on April 18, 2013, at the annual commemoration of the 1906 San Francisco Earthquake and became effective as of June 17, 2013. The first step of the implementation process will be the notice and screening of all buildings within the scope of the ordinance. 

The City of San Francisco estimates that roughly 3,000 of it’s city’s buildings possess a first floor with large windows or garages, making them vulnerable to collapse during an earthquake.

Since building owners have not retrofitted on their own, policy makers have crafted legislation that now forces them to have the work done. Only 53 soft-story buildings have been seismically reinforced through the city’s voluntary retrofit program, between early 2009 and September 2012. That’s only 2% of the estimated number of buildings needing reinforcement. 

Buildings found to be out of compliance will have a scarlet-letter sign posted on the property by the city stating: “This building is in violation of the requirements of the San Francisco Building Code regarding earthquake safety.” Owners who fail to satisfy the new law by their deadlines will face abatement procedures; and will have no choice but to endure a city notice on their property telling residents and passerby's that it’s in violation of the building code.

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