When the Loma Prieta earthquake struck San Francisco in 1989, it gutted the Marina neighborhood. While part of that was due to liquefaction effects caused by the area's underlying landfill construction, the problem was exasperated by the area's multiunit homes, which typically either had parking or shops built into the first floor. That's great for home values, but not so much of the building's structural integrity during a tremor, as you can see below.
“Earthquakes are particularly damaging to buildings with open spaces at street level because they collapse—the first-floor parking makes the building structurally weak and soft,” Colorado State University engineering professor John van de Lindt said in a press release. “There are tens of thousands of these multi-family buildings throughout California and much of the US, making this a serious safety issue.” That's why engineers are employing the world's largest shake table to design buildings that will remain standing, no matter how bad the tremor.
Located at the Jacobs School’s Structural Engineering Department eight miles east of the main UC San Diego campus, this 25-foot x 40-foot open air shake table will be the largest such device in America and the single largest outdoor system on the planet—only the 40 x 60-foot E-Defense (Earth-Defense) indoor shake table in Miki City, Japan has a bigger footprint. UCSD's $5.9 million table is hydraulically driven with six degrees of freedom and enough power to vibrate at 6 feet per second with a maximum force of 4.2 g—that's enough to accurately simulate the most destructive shakers on record.