Courtesy of cee-neesmrit1.cee.illinois.edu
A team of researchers from Stanford University and the University of Illinois have designed a new structural system that allows a building to be more earthquake-resistant.
When a quake strikes, the new system dissipates energy through steel frames in the building’s core and exterior. These frames are free to rock up and down within fittings fixed at their bases. Steel tendons made from twisted steel cables run the length of each frame, keeping the frames from moving so much that the building could shear. When the quake stops, these tensile tendons pull the frames back down into the “shoes” at their bases, returning the building to its plumb, upright position.
Greg Deirlein, professor of civil and environmental engineering at Stanford University and team lead of the project, explains, “This new structural system has the potential to make buildings far more damage resistant and easier to repair, so people could reoccupy buildings a lot faster after a major earthquake than they can now… What is unique about these frames is that, unlike conventional systems, they actually rock off their foundation under large earthquakes.”
The technology, which just completed testing at Japan’s Hyogo Earthquake Engineering Research Center, is the culmination of more than a decade of ideas and previous-gen technologies. While many elements of the system have been tested before, this is the first time they’ve been melded into a complete system and successfully put through the motions. For testing, the team constructed a three-quarters-size model of a standard three-story office building, with a footprint 120 by 180 feet, and a mass comparable to a full-size building. Then they shook the hell out of it. Even at a magnitude 1.75 times that of the 1994 Northridge earthquake — itself a 6.7 on the Richter scale — the only damage recorded in the frame was in the replaceable fuses.
Resources:
*New design keeps buildings standing and habitable after major earthquakes via www.physorg.com
*New Earthquake-Resistant Design Pulls Buildings Upright After Violent Quakes by Clay Dillow
photo from