Sometimes the best way to learn about something is to experience it. That is the concept behind a series of earthquake tests conducted this summer at an abandoned office park in Sherman Oaks.

A team of UCLA earthquake engineers have been forcibly shaking a former office building, which was damaged in the 1994 Northridge quake, to better understand how similar buildings may behave the next time a temblor strikes.

"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 UCLA 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 are planted on the building's roof, sending powerful vibrations equal to 200,000 pounds of force throughout the building while Wallace and his crew observe the effects from a mobile field lab stationed nearby. Hundreds of instruments installed throughout the five-story building test the performance of the beams, columns and floor slab, as well as non-structural components, like the sprinkler and piping systems.

Each shake test creates an artificial earthquake with roughly 25 percent of the force inflicted by the real Northridge quake, which measured 6.7 in magnitude.

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

In July, the researchers' shake tests were featured in newscasts by KNBC-Channel 4, KMEX-Channel 34 and KVEA-Channel 52.

Wallace and his team are part of the National Science Foundation-funded George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES), which brings together 16 institutions in a national network that shares data and equipment for earthquake research. The UCLA program, called nees@UCLA, specializes in field testing and monitoring of structural performance.

For more information about nees@UCLA, go to http://nees.ucla.edu/.

-Chris Sutton
8/10/04