Dancing bridges

Bridges that ‘dance’ during earthquakes could be the safest and least expensive to build, retrofit and repair, according to earthquake engineers at the University at Buffalo and the Multidisciplinary Center for Earthquake Engineering Research (MCEER).

The researchers recently developed and successfully tested the first seismic design methodology for bridge towers that respond to ground motions by literally jumping a few inches off the ground.

The new methodology allows steel truss towers that support bridge decks to be built or retrofitted at far less expense than conventional approaches, where each leg of a bridge tower is strongly anchored to its footing.

The design recently underwent successful testing on a model truss tower that is 20 feet high and weighs nine tons.

Testing was conducted on a six-degrees-of-freedom shake table in UB's Structural Engineering and Earthquake Simulation Laboratory (SEESL) - a facility within the UB School of Engineering and Applied Sciences.

‘Our approach is unconventional, counterintuitive,’ admitted Michel Bruneau, PhD, director of MCEER and UB professor of civil, structural and environmental engineering, who developed the new approach with Michael Pollino, a doctoral candidate in the UB Department of Civil, Structural and Environmental Engineering.