SCEC INSTANeT
News
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SCEC INSTANeT
News |
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By Jill Andrews On Tuesday, July 11, viewers were able to witness what happens to a house when it is hit with near-fault shaking recorded by a strong motion seismograph in the 1994 Northridge Earthquake in Los Angeles. Based on current design and building practices in California, the house had a tile roof, stucco exterior finish and all rooms were finished with painted gypsum board walls. This was the first time that the house had been fully furnished, with cameras installed to record the effect of strong motion on the building's equipment and contents, such as water heaters, shelving, TVs, bookcases, refrigerators and cabinets. The July 11 test was the culmination of five months of testing on the house, which had undergone a series of modifications to its configuration and materials and was subjected to a variety of different recorded earthquake motions played back through an earthquake simulator (or "shake table.") The Woodframe Project, of which the UCSD testing was a part, is funded by the Federal Emergency Management Agency (FEMA) through a grant administered by the California Governor's Office of Emergency Services (OES). For more information on CUREe and this project, see www.curee.org. Information from this dynamic testing, as well as subsequent testing on the same house, will also be used to develop new standardized guidelines for adjusting insurance claims after an earthquake. The California Earthquake Authority (CEA) is funding this portion of the project. Researchers at the Department of Structural Engineering at UCSD had been constructing, testing, and re-constructing the house in phases since early this year. The full-scale model was installed on the uniaxial shake table inside of one of UCSD's Department of Structural Engineering Powell Research Laboratories. The ground motion record for the July 11 test was the Rinaldi station recording of severe shaking in the Northridge Earthquake, with peak acceleration scaled slightly upward to 1.0g. Information from 300 sensors installed inside and outside the house provided valuable data that researchers will use to create computer simulations expected to aid in evaluating current design and construction practices. One of the surprise outcomes appears to be the power of stucco: an earlier test on the bare wood structure revealed that the top of the house swayed back and forth five inches relative to the bottom. In the test on the stuccoed version, the top swayed only one inch. "Those materials have the potential of providing a lot of earthquake resistance," said Caltech's Prof. John Hall in an interview with the NY Times. "The building was quite a bit stronger than when we previously tested it." Results from this and other tests to be
done on other woodframe structures will be used to modify designs
for new houses and for retrofit of existing buildings. For example,
the California Earthquake Authority (CEA) Governing Board has
recently approved a $300,000 research project on the house to
develop the nation's first standardized claims adjusting guidelines
for earthquake damage to woodframe homes. "This cutting-edge
research is a giant step forward in helping us better serve our
policyholders after an earthquake. For the first time, we will
have a scientific and engineering basis for claims adjusting
rather than using conjecture and guesswork," said Mark Leonard,
spokesman for CEA. Shake Test in the News: More than 350 news stories were generated the day of the event and immediately following by print, radio and television reporters. Major television network news organizations covered the event: CNN, Fox News, CBS, NBC, ABC World News, Good Morning America and their affiliates. The Discovery Channel is preparing a story and website scheduled to appear soon. KNBC and KFWB Radio aired stories for several days following. Printed stories ran in the Los Angeles Times (including a front page story the day after the event and a longer, more detailed article in the Business Section, with suggestions on how to prevent damage to your home through structural and nonstructural mitigation efforts); the San Diego Union Tribune; Associated Press State and Local Wire; and the New York Times (including a website, www.nytimes.com/quakes, which also features the video footage captured by USC's Distance Education Network on behalf of the CUREe Woodframe Project Element 5). Scientific American, Popular Science, and the Chronicle of Higher Education conducted interviews with Project Managers, and articles are scheduled to appear in upcoming issues. CUREe conducted a live webcast during the
test; Websurfers should go to www.curee.org
to view archived footage. Photos before, during and after the test
For more information on the Woodframe Project, Testing procedures and results, CEA and OES support, please contact: John F. Hall Robert Reitherman André Filiatrault Frieder Seible Chia-Ming Uang Mark Leonard Greg Renick |
Phone 213/740-5843 Fax 213/740-0011 e-mail: SCECinfo@usc.edu |
