June 27, 2016
On the world’s largest outdoor shake table at the University of California, San Diego (UC San Diego), DPR erected the tallest cold-formed, steel-frame structure ever to be tested on a shake table. As engineers, scientists, earthquake experts and media watched, the six-story building withstood a simulation of 150 percent of 1994’s 6.7-magnitude Northridge, California earthquake, shaking and rocking, but remaining structurally intact and safe.
“What we are doing is the equivalent of giving the building an EKG to see how it performs after an earthquake and a post-earthquake fire,” said principal investigator and UC San Diego structural engineering professor Tara Hutchinson.
The project is part of a $1.5 million three-week series of tests, analyzing how cold-formed steel structural systems perform in multi-story buildings located in high seismic hazard zones. Prior to this test, the largest building ever studied was a two-story residential structure in 2013. The structure experienced accelerations of 3.0 to 3.5 G’s at the upper levels, putting a tremendous amount of demand on the “light-gauge” structural frame. Lighter than a concrete, or hot-rolled structural steel building of the same height, the cold-form, light-gauge panelized structure is strong and flexible, thus able to move with the shaking instead of against it.
“The introduction of light-gauge structural systems in areas of high seismic hazard offers owners a superior option over traditional wood framing construction from economic, quality, safety, sustainability and overall building performance standpoints,” said DPR’s Zach Murphy, who is part of DPR’s cold-form steel prefab operations team. “We believe the results of these tests and future projects will continue to prove that this is the better way to build and create higher quality, safer structures in a cost-effective manner.”
In 2015, DPR constructed the MonteCedro senior-living community in Altadena, California, using prefabricated light-gauge panels. While the direct costs were close to wood-frame construction, additional savings were realized through faster schedule, better fire resistance and higher quality framing. DPR also recently built student housing at Otis College in Los Angeles using cold-formed structural framing.
Full video of this week’s shake test can be viewed below: