Page 35 - AAGLA-NOV2021
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 Member Update
 AIs My Building Vulnerable in An Earthquake?
By Ali Sahabi, Chief Operating Officer, Optimum Seismic
partments and other buildings in the $13.00 in repair costs, that’s a 13-to-1 savings ratio.
Los Angeles region, sit in the crosshairs of what experts agree could be the nation’s worst earthquake disaster. The Federal Emergency Management Agency uses Geographic Information System technology to estimate physical, economic,
and social impacts of disasters such as earthquakes. This nationally applied standard, called HAZUS, puts Los Angeles at the top of the list for annualized earthquake damage from an earthquake, followed by San Francisco, the Inland Empire, San Jose, Seattle, and San Diego.
These calculations are based on the age and density of Los Angeles’ built environment, along with the high likelihood of a major earthquake striking. The U.S. Geological Survey (USGS) says there is a 31% chance of a monstrous 7.5-plus magnitude quake striking in the next 30 years, most likely in the Greater Los Angeles Region. Thousands of buildings are at risk of major damage in the area.
One in Every 16 Buildings Damaged
If a 7.8-magnitude earthquake were to strike along the San Andreas Fault in Los Angeles , one in every 16 buildings – more than 300,000 structures – would be damaged, the USGS determined in its Shake-Out scenario compiled by more than 300 experts from a variety of fields. Under this scenario, the study also projected:
• 1,059 deaths
• 453 serious injuries
• 13,454 “non-fatal” injuries
• 121,339 displaced households (3.5 million individuals)
At least five pre-1994 steel moment-frame high-rise buildings would collapse, with about 5,000 people inside them if the quake strikes during regular business hours. And, as many as 50 low- and mid-rise concrete moment-frame buildings would collapse, and 900 unreinforced masonry buildings would be irreparably damaged, the study found. But those grim forecasts do not have to unfold. The National Institute of Building Sciences has determined that each one dollar invested in seismic retrofits of apartment buildings can save
Hazards of Soft-Story Apartments
Soft-story apartments are among the Los Angeles Area’s most vulnerable buildings. In earlier years, these soft-story buildings, with living units built above ground-level parking, were in favor because they enabled units to cover more of the property. Today we better understand the true costs of those old building designs.
Several of these buildings collapsed in the 1989 Loma Prieta earthquake and the 1994 Northridge earthquake, including one apartment building where 16 people died. Older soft- story buildings constructed before the 1990s cannot withstand the force of a major seismic event. During an earthquake, cracks can form on the beams; poorly reinforced columns lose cement and then collapse when moving sharply laterally.
Location is another important factor influencing earthquake risk for apartment buildings. Is your building sitting near a fault or in a liquefaction zone? City Hub L.A. has compiled an interactive map showing the ages of Los Angeles buildings from 1909 to 2000 – the vast majority of which were constructed in the 1970s or earlier. Visit cityhubla.github. io/LA_Building_Age/ or do a search for the City Hub L.A. building age map to see how your neighborhood might fare in a major earthquake.
The California Geological Survey offers a map of earthquake faults and liquefaction zones that can be searched by address at https://maps.conservation.ca.gov/cgs/EQZApp/app/. The City of Los Angeles provides a similar database at geohub.lacity. org/datasets. This is all important information to consider when assessing your risks. Take the first step to determining your building’s earthquake risks by calling Optimum Seismic at 833-978-7664 for a complimentary assessment of your building’s structural safety.
If you own a building that you believe may be vulnerable to damage – or if you live or work in one – it’s important to educate yourself on cost-effective measures that can be taken to save lives, protect your assets and property, and preserve the well-being of the community-at-large. Call Optimum Seismic at (833) 978-7664 or visit optimumseismic.com for a free building evaluation today.
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