The Federal Emergency Management Agency, Washington, D.C., found similar cost benefits in its report, “A Benefit Cost Model for the Seismic Rehabilitation of Buildings”. The two- year analysis of seismic retrofit scenarios applied to a variety of building types in locations throughout the U.S.
In its seminal report, “Natural Hazard Mitigation Saves”, the National Institute of Building Sciences, Washington, estimates that for every dollar spent on mitigation, society sees a resilience benefit of $4 to $11, depending on what you consider. These figures show that retrofits can make good business sense.
Some building owners are concerned that if they evaluate their older buildings and find they may be unsafe in a natural disaster, this knowledge will increase their legal liability. The reality is building owners in vulnerable buildings assume liability once they purchase the building. In a precedent-setting case in California, a jury found the owners of a clothing store liable when two employees were crushed to death by falling bricks during an earthquake in 2003. The jury determined the store owners were negligent because a reasonably diligent owner could have evaluated the building to determine whether it posed a safety hazard, in the same way an owner would have been responsible to check that the sprinkler systems were functioning. A building rating system, when used to make buyers, tenants, employees and visitors more aware of risks, can actually have the benefit of reducing an owner’s liability because it adds a measure of informed consent.
And retrofitting older buildings can increase their market value. When more than 90 percent of the building stock in a typical city is older than modern codes, most tenants or buyers don’t have the luxury of leasing or buying a brand new building. Those owners that can distinguish their buildings by retrofitting them to meet higher performance ratings will be able to take advantage of the increased public demand for resilience. In July, the U.S. Resiliency Council will be awarding Silver ratings to four masonry buildings in downtown Portland, Ore., that have been retrofitted in the past 10 years. These include both affordable and market-rate housing, retail and office space.
The preservation of our existing building stock is an essential component of creating more resilient communities. Rating systems like those developed by the U.S. Resiliency Council provide credible, consistent and meaningful data to owners about the benefits and costs of retrofit and are key to raising awareness of the public at large.
Shop 1841’s Owners Are Proactive Against Earthquakes
Shop 1841 is a 2-story retail building in the Southern California city of San Gabriel. The building site is located near a major earthquake fault. The original 1940s construction consists of a long-span wood truss roof supported by lightly reinforced concrete walls. The building was partially remodeled and seismically retrofitted in 2010 with steel moment frames added at the open storefront, plywood shear walls throughout the building, and struts and ties at the ceiling and roof.
The building was evaluated by Irvine, Calif.-based IDS Group engineers using the U.S. Resiliency Council Earthquake Performance Rating System and obtained four, four and three stars, respectively, for the dimensions of Safety, Damage and Recovery, resulting in a Silver Rating. The approach to seismic risk mitigation taken by the building owner, Star Building Group, is “just as we prepare and protect our buildings from the effects of weather, we should prepare for earthquakes, which are bound to occur in this region without warning.”
IMAGES: U.S. Resiliency Council