As part of a major international project to design more earthquake-resistant woodframe buildings, an engineer from Rensselaer Polytechnic Institute will be testing a damping system designed to act as a seismic shock absorber. The dampers, which have never been tested before in wood construction, will be installed inside the walls of a full-scale, 1,800-square-foot townhouse — the world’s largest wooden structure to undergo seismic testing on a shake table.
The height of woodframe buildings traditionally has been limited to about four stories, mainly due to a lack of understanding of how taller structures might respond to earthquakes and other natural disasters. “We don’t have accurate physical data to fully define how wood structures behave in earthquakes,” said Michael Symans, associate professor of civil and environmental engineering at Rensselaer. “We have some models, but their accuracy has not been verified with full-scale test data. This experiment will help us to further evaluate and refine those models.”
Symans will be supervising the damping tests at the University at Buffalo’s Structural Engineering and Earthquake Simulation Laboratory (SEESL), which is home to two adjacent three-dimensional shake tables where the test structure is anchored.
On July 6, a demonstration of the damper test will be open to the media, as well as broadcast live on the Web.
If you peer in via this link [and accompanying links at the site] during weekdays, you can follow the construction and set-up for the test. It goes live July 6th.
The damping system is essentially made up of fluid-filled shock absorbers installed horizontally throughout the walls of the house. “If we can channel some of the energy into the dampers, we can reduce the strain energy demand and thus reduce damage to the structure,” Symans said. The damping technology has been applied to steel and concrete buildings, but never before to wood structures.
John, I guess you and Leo should watch this — and see if you can do a retrofit to your homes?
I think seismic shock absorbers are a tool of Satan. They would undermine God’s ability to pour out his wrath through one of his favorite tools, the very useful earthquake. Don’t you think He created fault lines for a reason? I shouldn’t have to tell you we’re playing a very dangerous game, folks. Get right with the Lord, rather than trying to limit the damage he can do!
Ho-hum. The Japanese have centuries-old wooden Buddhist temples built to withstand earthquakes. Proven technology, btw.
I think the Japaense temples are of timber frame construction rather than the more modern (read “cheap, fast, not particularly durable”) stick/ballon frame construction we typically see today.
Properly done, timber frames are remarkable structures with each bit of the frame passing stresses on to the other members of the frame. Years ago I read a book on timber frame construction by Ted Benson in which he recounted trying to pull down an old timber frame barn. First they pulled out all foundation supports and expected the frame to collapse. It barely sagged. Then he hooked his four wheel drive truck to a cable and pulled. All he did was dig ruts. Then he cut all the braces out of the frame and hired a large tow truck to pull. It only hinged slightly where it was pegged. Finally he did what he had to do and disassembled the frame by hand, piece by piece.