Test of a new technique to make buildings bomb resistant
04 June 2001
WHAT: Test of a new technique to make buildings bomb resistant, preventing the kind of catastrophic collapse seen in the 1995 bombing of the Alfred P. Murrah Federal Building in Oklahoma City.
Inside a large bay devoted to seismic testing, University of California, Berkeley, civil engineers will simulate destruction of a critical support column of a full-scale replica of a portion of the first floor of a new federal courthouse soon to begin construction in Seattle, to determine if the hardening technology will prevent building collapse.
WHEN: 11 a.m. to noon TODAY, Monday, June 4
WHERE: Second floor of Davis Hall, UC Berkeley. Davis Hall is on Hearst Avenue on the north side of campus, at the intersection of LeRoy Ave.
WHO: Abolhassan Astaneh-Asl, UC Berkeley professor of civil and environmental engineering, who is testing this technology with scientists at Lawrence Livermore National Laboratory.
BACKGROUND: The collapse of the federal building in Oklahoma City, which killed 168 people, resulted from the destruction of a single supporting column. Astaneh will test a new mechanism to prevent such catastrophic collapse: a 1.25 inch cable embedded in the concrete slab floor and encircling the building. Should a support column be knocked out, the cable acts like the cable of a suspension bridge, supporting the floor so that it does not collapse. The goal is to give people time to escape, and perhaps even allow repair of the building.
Originally developed by the structural and civil engineering firm of Skilling Ward Magnusson Barkshire of Seattle, the technique is one of several blast resistant designs under study by Astaneh and colleague David B. McCallen, director of the Center for Complex Distributed Systems at Lawrence Livermore National Laboratory.
"This is an amazingly good system, one of the first efficient and inexpensive systems to come along for hardening buildings and preventing such tragic loss of life," Astaneh said. It could be used in new construction, as planned for the new federal building in Seattle and another in San Francisco, or to harden existing buildings.
During today's test, Astaneh will remove a critical column supporting more than 60,000 pounds and then push down on the building with a force of up to 240,000 pounds. This will test whether the cables can hold up the floor and prevent collapse by transferring the load to the rest of the building. The concrete slab floor of the full-scale replica should drop about three feet.