PULLMAN, Wash. — Researchers at Washington State University are continuing to work to improve construction techniques so that buildings and other structures hold up better under a seismic event like the 6.8 earthquake that rocked the Puget Sound region this week.
The work of WSU researchers has resulted in increased safety in a seismic event for between 100 and 200 bridges built throughout the 1990s in the Puget Sound region. In concrete bridge columns with a drilled shaft connection, WSU researchers suggested ways to improve the connection to the drilled shaft, thereby reducing the cost of construction and improving seismic resistance. In particular, the work showed the effectiveness of wrapping a steel, spiral reinforcement configuration around the drilled shaft. Research work for bridges with rectangular columns also led to a new reinforcement configuration that was superior to the one used in the past. The reinforcement involves two overlapping circular steel sections within the rectangular concrete column. Researchers recently finished a report on ways to retrofit columns on the Alaska Way Viaduct in Seattle to increase seismic resistance. For more information, contact David McLean, professor of civil engineering and associate dean of the College of Engineering and Architecture, 509.335.4653, mclean@wsu.edu.
Another WSU researcher is developing an innovative way to improve assessment of buildings for structural soundness after a temblor using ultrasound. The ultrasonic inspection technique employs bolts as diagnostic sensors in wood structures. Ultrasonic pulse-echo detection of fastener deformation within connections is used to measure connection displacement due to applied load, as well as energy dissipation within the connection. Overload magnitude (load beyond the yield point), internal connection damage and residual capacity also are assessed based on the results of ultrasonic inspection of deformed fasteners. The research will lead to an improved understanding of connection failure mechanisms, an enhanced ability to model the behavior of structural wood assemblies and a more complete understanding of systems response to static and dynamic forces. The advancements will eventually result in more accurate modeling and design of structural wood systems, thus minimizing unsatisfactory performance in such catastrophic events as hurricanes and earthquakes. For more information, contact Dave Pollock, assistant professor of civil and environmental engineering, 509.335.4922, dpollock@wsu.edu or Don Bender, director of the Wood Materials and Engineering Laboratory, 509.335.2829, bender@wsu.edu.
Over the past decade, more innovative seismic protection systems have been created in large steel and concrete buildings. There have been few such innovations in wood frame structures, however. Researchers in the Wood Materials and Engineering Laboratory are looking at the suitability of fluid dampers to dissipate energy in wood frame structures. For more information, contact Ken Fridley, professor of civil and environmental engineering, 509.335.7320, fridley@wsu.edu, or Bill Cofer, associate professor of civil and environmental engineering, 509.335.3232, wcofer@wsu.edu. In a separate project, Fridley and other WSU researchers also are working on a project examining the way multistory wood buildings transfer the shear (sliding) forces from an upper floor to a lower floor.
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