Bringing the house down

University of Buffalo earthquake engineers are launching a series of unprecedented seismic tests on a full-scale, wood-frame townhouse over the next nine months.

University at Buffalo (UB) earthquake engineers are launching a series of unprecedented seismic tests on a full-scale, wood-frame townhouse over the next nine months. The 33,000kg, 167m2 townhouse will be the largest wooden structure to undergo seismic testing on a shake table in the United States.

The testing at UB is part of a $1.4 million international project called NEESWood, funded by the National Science Foundation’s George E. Brown Jr. Network for Earthquake Engineering Simulation (NEES).

In November, the full-scale, furnished, three-bedroom, two-bathroom townhouse will be subjected to the most violent shaking possible in a laboratory, mimicking what an earthquake that occurs only once every 2,500 years would generate.

In that final test, the townhouse is expected to suffer massive damage, according to computer simulations performed by the UB researchers and colleagues at other NEESWood institutions.

To gather the data, the UB researchers are equipping the townhouse with 250 sensors that will provide detailed information about how each nook and cranny behaves during each simulated earthquake.

Twelve video cameras, eight indoors and four outdoors, will record the damage as it happens.

The NEESWood research is based on the premise that if more were known about how wood structures react to earthquakes, then larger and taller structures could be built in seismic regions worldwide, providing economic, engineering and societal benefits.

“We want to revolutionise the building of wood structures for seismic performance,” said Andre Filiatrault, professor of civil, structural and environmental engineering in the School of Engineering and Applied Sciences, a co-investigator on NEESWood and the lead investigator on the UB tests.

The experiments will be performed in UB’s Structural Engineering and Earthquake Simulation Laboratory (SEESL), the only laboratory in the US large enough and sophisticated enough to conduct the tests.

Between now and November, professors, students, contractors and local companies will be constructing, testing, repairing and testing again the two-story townhouse. It is being constructed on top of twin, movable shake tables in UB’s SEESL that will be set to deliver the exact same earthquake payload with precise simultaneous synchronisation.

During each of the six testing phases being planned, the townhouse structure will be subjected to five increasing levels of shaking in three dimensions, the most authentic ground motions that can be produced in a US laboratory. The ground motions will simulate increasing intensities that were recorded during the 1994 Northridge earthquake in the Los Angeles region.

The ultimate goal of the four-year NEESWood project is to develop a design philosophy for wooden structures in seismic regions so that taller and larger wooden structures can be built, up to six stories in height.