Expert Witness Blog
Structural engineering experts witnesses opine on the science and art of designing and constructing buildings, bridges, frameworks and other similar structures to safely resist the forces to which they may be subjected. Structural engineering researchers at Rice University are leading a new $1.6 million research program funded by the National Science Foundation to help design a new generation of “smart” shock absorbers for buildings and bridges in earthquake-prone areas.
To imagine what a building undergoes in an earthquake, Nagarajaiah suggests imaging yourself standing in a moving bus or train. “Riders make their bodies and muscles tense when the bus moves, and they relax as soon as the sudden motion stops,” Nagarajaiah said. “The typical steel-framed building or bridge can’t do that, but we want to find technologies like adaptive stiffness and damping systems that can give structures that ability.”
Nagarajaiah said about 100 U.S. buildings and bridges — including the famed Golden Gate Bridge — have been built or are being retrofitted with large, passive dampers, which work just like the shock absorbers in a car, using pistons and hydraulic fluid to absorb the impact of sudden shocks. But passive dampers do not have the ability to adjust their properties-such as stiffness and damping-in real time. By design, they perform the same way in every earthquake, but Nagarajaiah said quake researchers have discovered in recent years that all quakes are not created equal.
For more, see ‘Smart’ shock absorbers for quake-prone structures.