Photos courtesy of the University of California San Diego.
Researchers at the University of California San Diego have successfully tested the tallest cold-formed steel (CFS) framed structure ever placed on an earthquake simulator. The 10-story, 100-foot building was subjected to 18 earthquake simulations, including replicas of the 1989 Loma Prieta earthquake, in an effort to explore the potential for increasing height limits on CFS buildings in seismic zones.
Pushing the Boundaries of Steel Framing
Currently, building codes restrict CFS-framed structures to six stories or 65 feet in height. This groundbreaking test, known as CFS10, is designed to demonstrate that steel framing can safely support taller, more resilient structures, even in earthquake-prone areas.
“The building performed very well,” said Tara Hutchinson, project lead and structural engineering professor at UC San Diego. “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.”
The tests were conducted at the U.S. National Science Foundation funded outdoor shake table at UC San Diego, the only facility in the world capable of simulating earthquakes on buildings taller than 90 feet.
5 Reasons CFS Contributes to Resilience
It’s highly ductile. CFS can easily bend or stretch without breaking when force is applied. This gives it a higher degree of resistance to lateral loads, uplift and gravity loading, such as those imposed on a structure by seismic or high wind events
CFS is non-combustible. According to the Steel Framing Industry Association, both load-bearing and non-load-bearing CFS-framed assemblies are fireproof up to four hours when subjected to tests conforming to ASTM E119
CFS is durable. CFS is corrosion resistant. It does not retain moisture and will not harbor mold growth. CFS uses zinc or similar coatings to boost durability and will last hundreds of years before its corrosion resistance deteriorates
CFS is impervious to pests. CFS is one of the few building materials completely impervious to termites and other pests in any climate or building type
CFS is a highly sustainable material. Steel framing contains on average a minimum of 25% recycled content and is 100% recyclable at the end of its life
Shake Table Upgrade Proves Vital
The recent $17 million NSF upgrade to the shake table significantly enhanced the scope of testing. The system now simulates six degrees of motion — up/down, north/south, east/west, plus roll, pitch and yaw — mirroring real earthquake dynamics.
“The motions that we saw today demonstrated why that table upgrade was critical to the science that we do here,” said Ben Schafer, CFS10 project co-lead and professor at Johns Hopkins University.
During testing, researchers observed torsional motion in the building — something that could not have been captured prior to the upgrade. These 3D motion capabilities are essential for evaluating full structural behavior under realistic seismic events.
1,000 Sensors Record the Shake
The building was fitted with nearly 1,000 sensors to capture detailed performance data, including acceleration, displacement and strain measurements. Beyond the structural elements, researchers also assessed non-structural systems such as stairs and utilities, which remained functional even after intense shaking.
Researchers installed nearly 1,000 sensors throughout the building to capture detailed performance data, including acceleration, displacement and strain measurements.
“We have an outstanding set of data to analyze and digest,” said Hutchinson. “This will help improve building codes and support the design communities’ desire to use this excellent material in the construction of taller, lightweight, more resilient buildings.”
Because CFS is lightweight and non-combustible, it enables modular construction — shortening project timelines while offering high-performance seismic and fire resistance characteristics.
The test building integrated conventional stick-framing, panelized and volumetric modular construction within one building specimen, allowing a unique opportunity to document and compare the efficiency of each construction method, and any differences in structural performance.
Next Up, Fire Tests
The next phase of the CFS10 project involves fire testing to replicate real-world scenarios where fires may ignite after seismic events. These tests will assess how smoke, heat and particulates behave inside seismically damaged compartments.
The CFS10 project represents a major leap forward in validating the use of CFS framing for taller, more resilient and safer buildings. With promising results from seismic simulations and more testing underway, researchers are closer than ever to reshaping building codes and expanding the future of CFS construction.
