Nonstructural building components undergo seismic test

BUFFALO, N.Y.—In its initial public demonstration, the world’s first seismic testing apparatus for nonstructural components performed as designed on Oct. 12 at the University at Buffalo (UB) and MCEER, providing engineers with the first realistic, experimental method of simulating and evaluating how earthquakes damage building equipment, contents, and components. The National Science Foundation-funded Nonstructural Components Simulator (NCS) realistically simulated a fully equipped, upper-story hospital room experiencing two levels of seismic activity: a design basis earthquake, which has a 10-percent probability of occurring within the next 50 years; and a maximum considered earthquake, the largest earthquake shaking that a building could experience in its service life in a high-seismic zone in the United States.

The demonstration (view it online at https://nees.buffalo.edu/projects/ncs/webcast) took place in the Structural Engineering and Earthquake Simulation Laboratory (SEESL) in UB’s School of Engineering and Applied Sciences. More than 100 earthquake engineers and industry representatives from across the United States, who were attending the UB/MCEER symposium on Seismic Regulations and Challenges for Protecting Building Equipment, Components and Operations, observed the test.

The NCS is the only system in the world capable of realistically simulating how the contents and distributed systems (water, sprinkler, medical gas piping) in important buildings such as hospitals react to strong ground shaking and amplified floor motions, said Gilberto Mosqueda, Ph.D., assistant professor of civil, structural, and environmental engineering in the UB School of Engineering and Applied Sciences and lead designer and builder of the facility with Rodrigo Retamales, a doctoral student in the same department.

UB engineers and SEESL technicians constructed and equipped a 10-foot by 12-foot composite hospital room outfitted with numerous systems typical of a critical-care facility, ranging from mechanical systems, such as sprinklers and medical gas lines, to ceiling-mounted surgical lamps, a suspended ceiling, infusion pumps, and wall-mounted computer monitors. "Ben," a crash dummy provided by Calspan, Inc., of Buffalo, was seated on top of a gurney that had been secured in its stationary position. Nonetheless, the gurney was tossed about like a toy in both tests, while Ben—180 pounds of dead weight—hit the floor in the maximum event and was severely tossed about in the design basis quake.

During the design basis earthquake test, UB engineers said they were surprised to see wall-mounted EKG monitors fall from their pedestals, since they were mounted according to current California standards. The maximum considered earthquake test caused a few ceiling tiles to fall.

"These failures highlight some potential vulnerabilities that should be further studied," said Andre Filiatrault, Ph.D., professor of civil, structural, and environmental engineering at UB and director of SEESL. While he cautioned that general conclusions cannot be drawn from these tests, which were conducted primarily to demonstrate the capabilities of the NCS, nonetheless, he said that these unexpected failures point to areas where engineers and manufacturers may want to focus their joint efforts in the future.

The NCS is coming online just as a consortium of universities, led by the University of Nevada at Reno (UNR), and including UB, has been awarded a five-year, $3.6 million National Science Foundation NEES Grand Challenge grant to investigate the performance of nonstructural systems during earthquakes. In addition to complementary facilities at UNR, UB’s Nonstructural Components Simulator and versatile, twin movable shake tables will provide a test bed for these research studies to conduct experiments to better understand and improve the seismic performance of nonstructural systems, particularly ceilings, piping, and partition walls.