BUFFALO, N.Y. -- For homeowners in California and other
earthquake-prone regions, seismic safety has not exactly been
rocket science. Retrofitting measures typically are limited to
properly securing anchor bolts to foundations and nailing and
connecting wood shear walls to a structure's ground floor.
But residential earthquake engineering is about to get a boost
from, well, rocket science.
A technology first used during the Cold War to isolate ballistic
missile silos from vibrations will undergo its first test in a
full-scale, wood-frame townhouse in the University at Buffalo's
Structural Engineering and Earthquake Simulation Laboratory (SEESL)
on July 6.
The goal of the project is to find out if these fluid seismic
dampers, manufactured by Taylor Devices in North Tonawanda, would
minimize earthquake damage to wood-frame homes.
The test townhouse at UB was constructed this spring as part of
NEESWood, a four-year, $1.24 million National Science
Foundation-funded consortium project.
The goal of NEESWood is to develop a better understanding of how
wooden structures react to earthquakes, so that larger and taller
structures can be safely built in seismic regions worldwide.
Wood-frame construction accounts for an estimated 80-90 percent
of all structures in the United States and 99 percent of all
residences in California.
"The idea with this test is to apply dampers in a real-life
situation," explained Andre Filiatrault, Ph.D., UB professor of
civil, structural and environmental engineering and the leader of
the NEESWood experiments at UB. "We want to find out if
incorporating these dampers in a wood-frame residence is feasible
from all practical perspectives, including construction,
performance and economics."
Michael Symans, Ph.D., associate professor of civil and
environmental engineering at Rensselaer Polytechnic Institute in
Troy, N.Y., who holds three degrees from UB's School of Engineering
and Applied Sciences, will supervise the damper tests at UB.
If they prove successful, Taylor Devices, whose business is half
military and half seismic
applications as the result of a two-decades-old research
partnership with UB, now will be poised to enter the residential
market as well.
"It will be a brand new market for us," said Douglas P. Taylor,
chief executive officer of Taylor Devices and a UB alumnus. "And if
it works, this will be a double crossover technology," he said,
noting that this actually would be the technology's third
incarnation, since making the leap from missile silos to seismic
applications in the 1980s.
Currently, the Taylor Devices seismic dampers have been
installed in 180 commercial buildings and bridges worldwide,
ranging from the Petronas Twin Towers in Malaysia and the Beijing
Railway Station in China to California's San Francisco-Oakland Bay
Bridge and the Triborough Bridge in New York City.
But they have never been used in a wood-frame residence.
In the UB test, a total of four seismic dampers will be
installed within the perimeter walls on both floors of the house.
Once the walls are sheathed in plywood and gypsum, the dampers will
The testing will subject the 73,000-lb., 1,800-square foot
townhouse to a simulation of the magnitude 6.9 1994 Northridge
earthquake on UB's twin, movable shake tables. The tables are
capable of reproducing with high precision and synchronization the
ground motions recorded during the 1994 earthquake.
The shaking for the test will be exceeded only during the final
test of the house in November when it will be shaken vigorously to
simulate a far more powerful earthquake.
"Our computational analyses indicate that the four dampers will
substantially reduce the deformations and thus reduce damage within
the wood framing system," said Symans.
Each silicon-fluid-filled damper, measuring approximately 20
inches long and 3.5 inches in diameter, can dissipate about 10,000
pounds of force.
"That's equivalent in capacity to about 20 automotive shock
absorbers," said Taylor, noting that the average car has only
The dampers will take the energy of the earthquake and convert
it into heat, removing it from the structure, explained Taylor.
The heat then dissipates into the atmosphere, temporarily
boosting the dampers' temperature as high as 200-degrees
Fahrenheit; the temperature typically returns to normal in about 15
"We expect to be able to subject the house to much stronger
shaking with the dampers and have the same response in terms of
damage sustained that we did at much lower levels of shaking before
the dampers were installed," explained Filiatrault.
Successful results could pave the way toward eventual use of the
dampers in homes, Taylor said.
"While it's too early to predict yet what the cost would be to
purchase dampers for an average home, surveys we have done of
homeowners in California show that if we charged about $15,000 to
install dampers to minimize damage, consumers would be more than
willing to pay it," he said.
The seismic damping test at UB is the second of five different
tests that will take place in the first year of the NEESWood
project. In November, the furnished, three-bedroom, two-bathroom
townhouse will be subject to the most violent shaking possible in a
laboratory -- mimicking what an earthquake that occurs only once
every 2,500 years would generate.
The UB tests are the first step in moving toward
performance-based design for wood-frame structures. NEESWood will
culminate with the validation of new design processes using a
six-story, wood-frame structure that will be tested on the world's
largest shake table in Miki City, Japan, early in 2009.
NEESWood is a consortium of researchers led by John W. van de
Lindt, Ph.D., professor of civil engineering at Colorado State
University. The co-principal investigators are Rachel Davidson,
Ph.D., assistant professor of civil and environmental engineering
at Cornell University; Filiatrault of UB; David V. Rosowsky, Ph.D.,
professor and head of the department of civil engineering at Texas
A&M University, and Symans at Rensselaer Polytechnic
The NEESWood project is supported by the National Science
Foundation under Grant No. CMS-0529903 (NEES Research) and
CMS-0402490 (NEES Operations).
The University at Buffalo is a premier research-intensive public
university, the largest and most comprehensive campus in the State
University of New York.