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Research / Discovery

Midrise wood-frame building still standing

Updated July 14, 2009

Colorado State University along with industry leader Simpson Strong-Tie and other partners successfully led the world's largest earthquake shake table test in Japan on Tuesday, showing that midrise wood-frame buildings can be built to withstand major earthquakes.

“Thorough detailed analysis of the data won’t be available for weeks, but scientists are pleased with the initial results,” said John van de Lindt, principal investigator on the test and civil engineering professor at Colorado State University.

Forty-seconds of rockin' and rollin'

Tuesday’s 40-second test, approximating a 7.5 magnitude earthquake, was the strongest test, occurring on a seven-story condominium tower with 23 one- and two-bedroom living units. The test was held in Miki City, near Kobe, Japan, on the world’s largest earthquake shake table owned by Japan’s E-Defense, a facility of Japan’s National Research Institute for Earth Science and Disaster Prevention. The tower is the largest wood-frame building ever built and tested.

Little damage

“Early results of the testing this summer show that the building performed so well and had so little damage that it validated the design philosophy developed by Colorado State, other universities in the National Science Foundation’s Network for Earthquake Engineering Simulation and our industry collaborators,” said van de Lindt.

Safer, better performing, and more cost effective buildings

Steve Pryor, structural engineer for Simpson Strong-Tie and project collaborator added, "The testing thus far has shown that performance-based design for light-frame wood structures works. This will allow the engineering and building community to provide safer, better performing buildings in the most cost-effective manner."

Height of buildings in earthquake-prone areas may be influenced

The U.S. building industry rarely permits wood-frame buildings in excess of five stories in earthquake-prone areas. The data gathered from this test could increase the height of these buildings and influence the design of future wood-frame construction. The government of British Columbia is particularly interested in the results of the test after enacting a new law April 1 that increases the height of wood-frame structures from four to six stories.

Researchers spent the summer simulating earthquakes ranging from fairly frequent events expected every 70 years or so, to more powerful earthquakes that are only expected every 500 to 2,500 years, with magnitudes ranging from 6.7 to 7.5 on the Richter scale. The Northridge earthquake, for comparison, measured roughly 6.7.

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July 11, 2009

A whole lot of shakin' going on

On Tuesday, July 14, Colorado State University researchers - in collaboration with Simpson Strong-Tie - will conduct the world's largest earthquake shake table test near Kobe, Japan, simulating the ground motion of an earthquake so strong it only occurs every 2,500 years.

That’s about 180 percent more intense than the 1994 Northridge, Calif., quake, or about 7.5 on the Richter scale.

Testing seven-story building design

The goal of John Van de Lindt, CSU civil engineering professor, and his partners, is to prove that the design of the seven-story, wood-frame condominium building they built is tough enough to withstand the shaking. Currently, earthquake-prone areas prohibit the construction of mid-rise – six- or seven-story - wood-frame buildings. In the United States, 39 states are at risk for earthquakes.

Live webcast Tuesday

NSF will conduct a live webcast with van de Lindt and others involved in the test at 9 a.m. MDT Tuesday, July 14. (Editor's noteUsername and password requirements will be waived at 9 a.m. MDT Tuesday for the webcast.)

Van de Lindt’s team will examine the effects of the quake on a seven-story, 40-foot by 60-foot condominium tower with 23 one- and two-bedroom living units – the largest building ever built on the world's largest shake table in Miki City, Japan. The shake table is a platform measuring approximately 65 feet by 49 feet and can support building experiments weighing up to 2.5 million pounds. The seven-story building sitting on top of the table weighs nearly a million pounds.

Culmination of series of seismic tests

The Japanese event is the culmination of a $1.4 million grant from the National Science Foundation for a series of seismic tests - known as the Network for Earthquake Engineering Simulation or NEESWood Capstone tests - that have occurred at smaller shake tables across the United States, including several at Colorado State. That grant is a collaboration among five universities, with Colorado State University in the lead. Also participating are Texas A&M University, RPI, University at Buffalo, and University of Delaware.


Contact: Emily Wilmsen
E-mail: Emily.Wilmsen@colostate.edu
Phone: (970) 491-2336