What is soft-story seismic retrofitting?

How Much Will That Retrofit Run Me?

The cost of a soft-story retrofit varies greatly depending on the scope of the project, but a large building can cost upward of $100,000 to retrofit in some cases [source: Selna].

Clearly, soft-story seismic retrofitting isn't cheap, but it can be money well spent. A Caltech survey found a 7:1 benefit-to-cost ratio for money spent on shear walls and a 4:1 ratio for money spent on steel frame retrofits [source: Association of Bay Area Governments]. Still, building owners often don't want to deal with the hassle and expense of the process, so cities are adopting a variety of approaches to encourage or, in some cases, even require owners to retrofit their buildings.

In Berkeley, for instance, owners of soft-story buildings must have their buildings assessed for structural weaknesses. Whether they then choose to rectify those weaknesses is up to them, but if an owner decides to forgo the expense, he or she must post a warning informing all residents and guests that the building is likely unsafe in the event of an earthquake. Other cities encourage retrofits by waiving zoning requirements for parking and other building codes, providing tax incentives or preventing building owners from performing other renovations or improvements until they've first retrofitted their building. Going further, cities like Fremont simply call for owners of soft-story buildings built before 1978 to retrofit them or face heavy fines [source: Community Action Plan for Seismic Safety]. Hopefully, policies like these, rather than another earthquake, will bring much-needed attention to the issue of soft-story retrofitting.

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  • 2006 International Existing Building Code. "Earthquake Hazard Reduction in Existing Wood-Frame Residential Buildings with Soft, Weak or Open-Front Walls." 2006. (Sept. 17, 2011)
  • Association of Bay Area Governments. " Soft-Story Buildings." Aug. 30, 2011. (Sept. 19, 2011) http://quake.abag.ca.gov/housing/softstory/
  • Association of Bay Area Governments. "Soft story Residential Buildings in Earthquakes Risk Management and Public Policy Opportunities." Nov. 14, 2005. (Sept. 17, 2011) http://quake.abag.ca.gov/wp-content/documents/PR-Soft story.pdf
  • Chong, Jia-Rui. "Quake vulnerability of 'soft-story' apartments in state still widespread." Los Angeles Times. Jan. 17, 2009. (Sept. 19, 2011) http://articles.latimes.com/2009/jan/17/local/me-quake-building17
  • Community Action Plan for Seismic Safety. "Memorandum: Soft-Story Mitigation Programs in Other Communities." Oct. 23, 2008. (Sept. 19, 2011) http://www.sfcapss.org/PDFs/SS%20MitigationOtherCommunitiesOct23.pdf
  • Itsekson, Alexander. "On Solid Ground." San Francisco Apartment Association. 2010. (Sept. 19, 2011) http://www.sfaa.org/may2010/1005itsekson.html
  • Jessup, Julie. Tokamatsu, Gordon. "Thousands of Soft story Structures Still Need Retrofitting." NBC Los Angeles. Feb. 4, 2011. (Sept. 17, 2011) http://www.nbclosangeles.com/news/local/Many-Residences-Still-Unprepared-for-Big-Quake-115330879.html
  • Reich, Kenneth. "Study Raises Northridge Quake Death Toll to 72." Los Angeles Times. Dec. 20, 1995. (Sept. 19, 2011) http://articles.latimes.com/1995-12-20/news/mn-16032_1_quake-death-toll
  • Selna, Robert. "S.F. 'soft story' buildings at risk in quake." San Francisco Gate. Dec. 11, 2008. (Sept. 17, 2011) http://articles.sfgate.com/2008-12-11/news/17129780_1_loma-prieta-buildings-large-earthquake-scientists

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