Growing concern over the threat of a major earthquake in California has sparked a statewide movement for resiliency and pending legislation that calls for the identification of buildings most vulnerable to seismic damage and collapse. Scientists contend that stress along the San Andreas fault has been building with little relief since the mid-1800s. The next “Big One” could come at any moment and reach a 7.5 or higher magnitude. The force of such an event could result in twice the damage of Hurricane Katrina and be up to 45 times more destructive than the Northridge earthquake that hit southern California in 1994.
The recently released “The Case for Earthquake Resilience: Why Safer Structures Protect and Promote Social and Economic Vitality” describes in depth the threats of earthquakes on society, and the economic benefits that come from having safer structures in a community. The paper was written by key members of the Seismic Resilience Initiative (SRI), a United States Resiliency Council-led working group that includes BizFed, Local California Building Department Leaders and Structural Engineers Association of California, with technical assistance from the California Seismic Safety Commission, California Office of Emergency Services, California Department of Insurance, and International Code Council. SRI’s mission is to promote statewide policy that will identify buildings known to present a heightened seismic risk of death, injury and damage based on their age, structural system, size and location.
|The United States Resiliency Council’s mission is to establish and implement meaningful rating systems that describe the performance of buildings during earthquakes and other natural hazard events; educate the general public to understand these risks; and, thereby improve societal resilience. The new whitepaper is posted at www.usrc.org.
The SRI-inspired AB2681, introduced earlier this year by California Assemblyman and longtime earthquake preparedness advocate Adrin Nazarian, aims to help cities identify buildings that could be at significant risk during a major quake, and establish funding sources to help cover the costs impacted by the law. A snapshot of California’s vulnerabilities will provide a thorough assessment of the potential impacts, while spotlighting communities where there is an urgency to address the matter. If adopted, the legislation will:
1. Develop criteria to identify seismically vulnerable building types.
2. Direct building departments to develop an initial list of potentially vulnerable buildings.
3. Notify building owners that they may have potentially vulnerable buildings.
4. Direct noticed owners to verify the vulnerability of the structure.
5. Task agencies with maintaining a statewide data repository of potentially vulnerable buildings.
6. Identify possible funding mechanisms to offset costs to building departments.
“The identification of these buildings is an important step in ascertaining the extent to which our cities are threatened,” says Nazarian. “We have to identify our weaknesses in order to make our communities stronger.”
United States Resiliency Council Executive Director Evan Reis notes that certain structures are more prone to damage from seismic shaking. They generally include older wood-framed, soft-story structures, unreinforced masonry, tilt-up concrete, nonductile concrete, and steel moment frame buildings. “Every building made stronger represents added potential for communities to spring back from a major earthquake,” he affirms. “This is very important not only in terms of saving lives, but in preserving social and economic order.”
“Case for Earthquake Resistance” co-author David Khorram, president of California Building Officials and City of Long Beach superintendent of Building Safety, finds that retrofits not only safeguard communities, but building owners too. “Researchers have found that retrofits bring significant cost benefits to the building owners,” he adds. “In the end, it makes good business sense. It protects an owner’s equity and income, and guards against potential liabilities.”
Co-author Ali Sahabi, chief operating officer of Optimum Seismic Inc., BizFed board member and longtime sustainability champion, stresses the important impact that resilient communities have on the well-being of the state and nation. “Planning for disaster before it strikes is a major component of sustainability,” he contends. “Foresight and preparation are our only defense against major earthquakes. What we do today as a society will impact our communities long into the future.”