University of Nevada, Reno's Earthquake Lab Simulates Trucks on a Bridge During an Earthquake
Posted on September 23, 2011The University of Nevada, Reno has an amazing Large-Scale Structures Earthquake Engineering Laboratory that can be used to simulate large earthquakes. The lab contains a 145-foot-long, 162-ton steel and concrete bridge, which was built atop four large, 14-foot by 14-foot, hydraulic shake tables.
The lab recently simulated an earthquake with six full-size pickup trucks on top of the 16-foot-high steel bridge. The four, 50-ton capacity shake tables are simulating the 1994 Northridge, Calif. earthquake, which resulted in 33 deaths, 8700 injured and $2 billion damage in southern California. The lab simulates a percentage of the strength of the Northridge quake at a time. It is capable of simulating more than twice the strength of the Northridge quake.
Ian Buckle, professor of civil engineering and director of the large-scale structures lab, says, "We took the bridge to its extreme, almost double what we planned at the outset. Preliminarily we see that in low amplitude earthquakes the weight of the vehicles actually helps the seismic effects on the structure, while at higher amplitudes the trucks hinder considerably the bridges ability to withstand an earthquake."
Buckle also says, "Whether you saw the experiment in person or watch the video, remember that this is a 2/5 scale model, and the movement you see would be two and a half times greater on a full-scale bridge. It would be scary to be driving under those conditions."
Buckle also says that bridges are not currently designed for heavy traffic and a large earthquake at the same time. This particular experiment was designed to help determine whether the presence of trucks helps or hurts the behavior of the bridge during an earthquake.
Danielle Smith, a graduate student working on the project, says, "There's no other lab in the world like this, so it's been a lot of fun. It's exciting when you get to shake things." Take a look:
Photo: Mike Wolterbeek, University of Nevada, Reno