UCSD - University of California - San Diego
09/16/2025 | Press release | Distributed by Public on 09/16/2025 07:13
Trial by Fire–and Simulated Earthquakes
Published Date
September 16, 2025Article Content
When a 10-story test building in San Diego shook and twisted this summer, it wasn't because of a real earthquake - it was part of a federally funded experiment designed to make future buildings safer when the next big one strikes.
A few weeks later, smoke and flames fanned out the window of the building's ninth floor. The researchers had returned for fire testing to see how a building damaged by earthquakes would withstand a blaze.
The structure was built this year at the UC San Diego earthquake simulator located in the Scripps Ranch neighborhood of San Diego. Funded by the U.S. National Science Foundation (NSF), the facility is one of the three largest shake table facilities in the world and the only one located outdoors. The simulator, part of UC San Diego's Englekirk Structural Engineering Center, is capable of shaking structures in six directions: back and forth, up and down, left to right, and in the three rotational movements of yaw, pitch and roll.
Researchers used drones to monitor the spread of the fire. Fire fighters monitored the tests.
These tests focused on a building made of cold-formed steel, or CFS - a lightweight material made from 60% to 70% recycled steel. Currently, building codes that protect residents' safety in the United States limit this type of building to 65 feet tall, or six stories, in areas with moderate to high seismic risk. Researchers are asking whether the limit could be increased to 100 feet or 10 stories. And so far, test results point to yes.
"The building performed very well," says Tara Hutchinson, project lead and professor in the Department of Structural Engineering in the Jacobs School of Engineering. "Despite 18 earthquake tests of increasing intensity, the load-bearing structural system retained its integrity, and nonstructural components remained functional."
"Cold-formed steel has a lot of wonderful benefits that can support communities resilient to multiple hazards in the future," she added.
Cold-formed steel elements are lightweight and easy to handle and can lead to innovation in construction. For example, cold-formed steel studs, joists and sheets can be assembled into modular units off-site. These units can then be assembled on a construction site to raise a building, similar to the way LEGO sets are built. This technique dramatically shortens the amount of construction time on site, in addition to other benefits such as reducing construction waste and added precision of the final product.
Professor Tara Hutchinson, left, discusses the tests in one of the building's rooms after a fire test.
The tests demonstrated the importance of a major upgrade to the shake table funded by the NSF. The $17 million project gave the table the ability to move in six degrees of freedom. This allows researchers to subject structures to realistic earthquake scenarios-real earthquakes shake the ground in multiple directions - and in the 10-story cold-formed building program the team did just that. The shaking scenarios with multiple directions resulted in twisting response, a natural characteristic of taller buildings. "Exciting a building with multiple directions of earthquake loading allows us to study realistic scenarios we would have to otherwise wait for mother nature to impose. This data is essential to benchmark numerical models and ultimately help change building codes," said Hutchinson.
"So this facility, funded by the National Science Foundation, is a total game changer for earthquake engineering," said Ben Schafer, co-principal investigator on the project and a professor at Johns Hopkins University. "The motions that we saw during this series of tests demonstrated that the table upgrade was critical to the science that we do here."
Researchers conducted fire tests on the building's sixth and ninth floor.
Following the earthquake tests, Hutchinson partnered with Richard Emberley, a faculty member at Cal Poly San Luis Obispo, to gauge how the cold-formed steel building, which had its interiors finished with drywall, would withstand controlled fires. Major fires after earthquakes have become rarer since the 1906 blaze that destroyed San Francisco after a 7.9 magnitude temblor. But earthquakes can rupture gas lines and electrical wiring, providing conditions that could ignite a fire.
"One of the reasons that it's important to do a fire following an earthquake test is to look and to try to understand the resiliency of buildings," Emberley said.
The researchers are now trying to determine how high temperatures affect the layers of drywall that protect the building's steel skeleton after it has been damaged in earthquakes. Bringing together fire engineers and structural engineers is key here, Emberley said.
None of this would be possible without federal funding, the researchers said. "Federal funding has supported undergraduate and graduate students in this program, in addition to supporting operations at this outdoor shake table. Without the National Science Foundation and this unique, large-scale outdoor shake table, researchers would have to wait for the next earthquake to occur. And we might be significantly unprepared for the next one," Hutchinson said.
Experiments conducted in this shake table's controlled environment have already led to changes in building codes, making Americans safer during future earthquakes.
More information about the project, including partners and sponsors at cfs10.ucsd.edu.
Share This:
UCSD - University of California - San Diego published this content on September 16, 2025, and is solely responsible for the information contained herein. Distributed via Public Technologies (PUBT), unedited and unaltered, on September 16, 2025 at 13:13 UTC. If you believe the information included in the content is inaccurate or outdated and requires editing or removal, please contact us at [email protected]