July 18, 2014
Concrete Bridge Survives Series Of Simulated Earthquakes
Mike Wolterbeek, University of Nevada, Reno
A 70-foot-long, 52-ton concrete bridge survived a series of earthquakes in the first multiple-shake-table experiment in the University of Nevada, Reno's new Earthquake Engineering Lab, the newest addition to the world-renowned earthquake/seismic engineering facility.
"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 would be expected to do."
The set of three columns swayed precariously, the bridge deck twisted and the sound filled the cavernous laboratory as the three 14- by 14-foot, 50-ton-capacity hydraulically driven shake tables moved the massive structure.
"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."