:: UCLA TODAY Home

©2004
The Regents of the University of California
 

Photo courtesy of NEES@UCLA Project Manager Daniel Whang (left) and student researcher Eunjong Yu review testing protocol before doing a shake test at an abandoned office building at 4827 N. Sepulveda Blvd. in Sherman Oaks. The rubble is from a previous test.

Did you feel that? Engineers shake office building

by CHRIS SUTTON

Sometimes the best way to learn about an earthquake is to experience it. But why wait for Mother Nature?

A team of UCLA earthquake engineers conducted a series of shake tests on an abandoned office building in Sherman Oaks to better understand how similar buildings may behave the next time a temblor strikes. Located on North Sepulveda Boulevard near the 101 freeway overpass, the building had been damaged in the 1994 Northridge quake.

“Opportunities to conduct experiments like these are rare and are important for understanding more about structural responses to seismic activity,” said John Wallace, a civil and environmental engineering professor in the Henry Samueli School of Engineering and Applied Science. “They give us real insight into why some buildings perform poorly during earthquakes.”

Large devices called eccentric mass shakers were planted on the roof of the Sherman Oaks building, sending powerful vibrations equal to 200,000 pounds of force throughout the structure while Wallace and his crew observed from a nearby mobile field lab. Each shake test created an artificial earthquake with roughly 25% of the force inflicted by the real Northridge quake, which measured 6.7 in magnitude. Hundreds of instruments installed throughout the five-story building tested the performance of the beams, columns and floor slab, as well as non-structural components like the sprinkler and piping systems.

The UCLA field-testing and monitoring equipment used in the experiment can also be used to see what happens to other structures such as dams and bridges during simulated earthquakes.

Wallace and his team are part of the NSF-funded George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES), which brings together 16 institutions to share data and equipment for earthquake research. For more information about the UCLA program, called nees@UCLA, go to //nees.ucla.edu/.