A 70-foot-long, 52-ton bridge was tried and tested by the University of Nevada, Reno’s new Earthquake Engineering Lab. The experiment was to see if the bridge would survive a series of 10 earthquakes – and it did!
“It was a complete success. The bridge withstood the design standard very well and today went over and above 2.2 times the design standard,” John Stanton, civil and environmental engineering professor and researcher from the University of Washington, said. Stanton collaborated with Foundation Professor David Sanders of the University of Nevada, Reno in the novel experiment.
“The bridge performed very well,” Sanders said. “There was a lot of movement, about 12 percent deflection – which is tremendous – and it’s still standing. You could hear the rebar inside the columns shearing, like a zipper opening. Just as it was designed to do.”
The bridge was designed at the University of Washington in Seattle and built atop hydraulically driven shake tables. The ground motions of the simulated earthquakes were similar to those recorded in the deadly and damaging 1995 magnitude 6.9 earthquake in Kobe, Japan.
The bridge shook, rattled and twisted but was still standing at the end of the experiment.
“Sure we broke it, but we exposed it to extreme, off-the-scale conditions,” Stanton said. “The important thing is it’s still standing, with the columns coming to rest right where they started, meaning it could save lives and property. I’m quite happy.”
If further experiments are as successful as this one, the team hopes its new rocking, pre-tensioned concrete bridge support system will be implemented around the country in hopes of saving lives, reducing construction time and minimizing earthquake damage.