Protecting the national economy is not the usual job for UB's Multidisciplinary Center for Earthquake Engineering Research. However, the center is testing a new bridge design that could be the future of American "economic lifelines," according to UB professor Michel Bruneau.
A professor in the Department of Civil, Structural and Environmental Engineering in the School of Engineering and Applied Sciences, Bruneau said his new method of building short-span bridges is more resilient and is particularly effective for highway overpasses and bridges over small waterways.
"If you look at the complete inventory of bridges you'll quickly realize that it's not only long-span landmark bridges that are lifelines to the nation's economy," Bruneau said. "Losing some of these more mundane-looking lifeline bridges can be devastating."
Problems with the way bridges are currently built and the materials used to build them are vulnerabilities Bruneau targeted in developing his design.
"With traditional concrete, when there is a direct pressure, it will typically breech. You end up with no concrete left between the rebar," Bruneau said. "This will cause the bridge to possibly collapse, (and) that line will have to be closed until it can be repaired."
Bruneau's solution utilizes a "composite design" of steel and a concrete that maintains its shape to overcome traditional structure failures.
"We flip the column inside out and use the steel as a shell, and fill it with non-shrink concrete. This is called a composite design. They resist the force together more than the sum of their parts."
MCEER's main focus is to improve the seismic resilience of communities, according to Andre Filiatrault, the center's deputy director. The facilities, however, also helped Bruneau make his design less susceptible to terrorist attacks.
One scenario that Bruneau considered was a car trunk packed with explosives.
"The bridge would have a major kink in it, but you wouldn't have to close the bridge," Bruneau said. "It could still carry traffic and its own weight while undergoing repair."
For highway departments, these bridges would not only be easier to repair while in use, but also easier and faster to construct. The tubes, which act as a form while the concrete sets, can still hold the bridge's weight and traffic, minimizing construction time before a bridge is ready for use.
Because no additional materials are used as reinforcements inside the tubes, building costs will be very close to the same as those of a conventional bridge.
With heightened awareness for weaknesses vulnerable to terrorist attacks, Filiatrault explained how Bruneau's project applies to MCEER's goals.
"Professor Bruneau's project deals with resilience of community against multiple hazards and how to mitigate in that situation," Filiatrault said. "It's a design that jointly prevents earthquake and blast damage."
Photo: Courtesy of Matthew Messina, from the RMBERS' Instagram page
