In July 2025, the University of California put the tallest steel-framed building ever tested on its earthquake simulator to the test. The results were impressive.
On the count of three, the tallest steel-framed building ever tested on an earthquake simulator started to sway. The earthquake simulator – one of the three largest ‘shake tables’ in the world and the only one located outside, which pushes the boundaries of height limits – tested the ten-storey, 100-foot cold-formed steel building with the simulations of real earthquakes. Based at the University of California in San Diego and funded by the U.S. National Science Foundation, the test was designed to understand if the height limits for buildings made of cold-formed steel built in earthquake zones could be increased.
Cold-formed steel was chosen for the test because it is a lightweight, sustainable material made from 60% to 70% recycled metal that is not combustible. And, because it is a lightweight material, cold-formed steel can be assembled in modular units, which significantly reduces the amount of construction time compared to traditional methods of construction.
Pushing the limits of earthquake zone construction
In the United States, building codes limit cold-formed steel construction to 65 feet or six storeys, but this test was looking at whether it is possible to increase the limit to 100 feet or ten storeys even in seismically active areas. The test results seemed to indicate that this should be possible.
“The building performed very well,” said Tara Hutchinson, the project’s lead and a professor at the University’s Department of Structural Engineering. “Despite 18 earthquake tests of increasing intensity — including three very large at and above what design engineers must consider in designing a building — the load-bearing structural system retained its integrity.”
Researchers were expecting the building to suffer some damage to its non-structural components, but the stairs, which are crucial to allow the building’s occupants to safely evacuate the building and are designed to move with the building, were still functional.
“Within this building we installed nearly a thousand sensors to measure its response in terms of acceleration, displacement and local strains – we have an outstanding set of data to analyze and digest and ultimately to help improve building codes and support the design communities’ desire to use this excellent material in the construction of taller, lightweight, more resilient buildings,” said Hutchinson.
Time to get fired up
After carefully reviewing the physical state of the building after the earthquake tests, the researchers are now preparing for a final phase of live-fire testing. Led by Professor Richard Emberley at Cal Poly-San Luis Obispo, these tests are aimed at understanding the temperature, smoke and particulate spread throughout compartments in the building that were seismically damaged. This is a real scenario referred to as ‘fire-following earthquakes.’ These could be triggered by gas or other hazardous substances, which could serve as an ignition source. Hutchinson said: “Cold-formed steel is non-combustible, unlike wood and some other building materials, an important beneficial characteristic if fires are a concern.”