Bridges Include Elements to Make Them Stand after Shaking
Seismic bridge engineering used to be more of an “art” and less of a science—but it’s making progress as the latter, says Frieder Seible, dean of the Jacobs School of Engineering at the University of California, San Diego. Through lessons learned from real quakes and advancements in computer modeling, “we’re developing a scientific approach” to retrofits.
The approach informs continuing research on seismic behavior of bridges. “The most recent seismic events...have influenced code changes that are still being implemented today,” says Mark Christensen, engineer with TRC Imbsen, Sacramento. Colleague Shin-Tai Song adds that evaluation of recent quakes “indicates that the majority of damage can be related to the elastic design philosophy widely adopted prior to 1992, which specified a relatively low design lateral force level.”