Test Will Help Scientists Improve Builing Codes, Prevent Fires
7:51 AM, Apr 16, 2012
One of the biggest efforts ever made to understand how earthquakes affect buildings begins Tuesday at UC San Diego, where engineers will violently shake a five-story structure fitted with 500 sensors and 70 cameras.
The test is the first in a series meant to help scientists improve building codes and prevent fires, a common aftereffect of quakes.Scientists have shaken the skeleton of buildings before, but this is a complete mid-rise with state-of-the art ceilings, electrical systems, furniture and a working elevator. The top two floors have been designed as a mock hospital, complete with a surgical suite and an intensive care unit. It is the most elaborately detailed quake test building ever created.The testing will be done at UC San Diegos Jacobs School of Engineerings facility in Scripps Ranch. The 1.4 million-pound building has been placed on top of the countrys biggest shake table, which is capable of simulating motions from nearly all past earthquakes, including the strongest ones.What we are doing is the equivalent of giving this whole building an EKG to see how it performs after an earthquake and a fire, said Tara Hutchinson, the UC San Diego engineer who is leading the $5 million project.The projected was funded by the National Science Foundation, government agencies and by about 40 industry partners, which contributed equipment and materials that will help make for more realistic tests.This weeks test will simulate the 6.7 quake that hit Northridge in 1994, killing about 60 people and causing $20 billion in damage. Future tests will replicate the 8.8 quake that struck Chile in 2010. There have been only a handful of quakes in recorded history bigger than the Chile event, which killed more than 500 people. The quake also generated a tsunami that sent waves all the way to San Diego. Engineers will also simulate motions from a magnitude 8.0 temblor that occurred in Peru in 2007, with ground motions similar to what could happen off the coast of Northern California.Scientists are especially interested in learning about how a large quake could affect hospitals, and the sort of computer centers used by emergency personnel. The vulnerability of medical centers was graphically exposed in 1971 during the 6.6 Sylmar earthquake, which left much of the Veterans Affairs Hospital in San Fernando in ruins while also killing almost 50 people. The Olive View Hospital, which had opened only months earlier, partially collapsed.The testing also will focus on refining scientists basic understanding on ground motion. The shake table will simulate the 7.9 quake that hit Denali, Alaska, in 2002, largely because that shaking resembles the sort of ground motion that can happen in Southern and Central California.For the initial tests, the building was raised four inches so it could be placed on top of four isolators that focus energy at the base of a building to limit damage in higher stories. Later, the building will be jacked up so that the isolators can be removed. The buildings foundation will then be anchored back onto the shake table, which is how most buildings are situated.After damaging the building with a number of strong earthquake motions, local fire burn tests will be performed in select locations of the building to recreate fire following earthquake scenarios.Credits: San Diego State University managed the construction of the earthquake test building. The projects collaborators included the National Science Foundation, California Seismic Safety Commission, Charles Pankow Foundation, Howard University and Worcester Polytechnic University.For other stories from our news partner, go to utsandiego.com.