10-story cold-formed steel building seismic tests at the large outdoor shaketable at UC San Diego (CFS10)

During June and July 2025, a major collaborative effort was carried out at UC San Diego’s Englekirk Structural Engineering Center (NHERI@UCSD) to test how a full-scale 10-story cold-formed steel building responds to extreme shaking and live fire (CFS10 project). Led by Prof. Tara Hutchinson at UCSD, the project brought together researchers, engineers, industry, and agencies from across the country to improve building safety and performance under disaster conditions. This building specimen was designed beyond current code limits to test advances in steel sheathed shearwalls and heavy chord stud details.

As part of this large-scale testing, the Community Seismic Network (CSN) deployed 75 triaxial seismic sensors throughout the structure to help capture detailed dynamic response data from structural and non-structural components. CSN had 4 triaxial sensors on every floor diagraphm including the roof, 9 on stairway midway landings, 10 on two sets of balconies, 7 on gas and water pipes, and 5 on windows and doors. Acceleration data were recorded continuously (24/7) throughout the two months of seismic and fire testing.

Left: Photo of 10-story building. Right: Typical CSN sensor layout (triangles) on a level with balconies.

CSN sensors recorded data continuously at 200 sps, capturing both the seismic shake tests as well as ambient vibrations produced by environmental sources such as activity inside the building, traffic around the structure, and motors and machinery connected with the facility. The spectrograms below show six hours of data recorded by the NS component of a sensor on the top (Roof) level on June 25. They clearly show the response during one of the shake tests that used scaled 1989 Loma Prieta ground motions as input, and during periods when people were walking inside the building before and after the shake test.

Spectrograms of six hours of data recorded on Roof Level sensor on June 25, 2025. Top row shows 0-100 Hz and bottom row shows 0-10 Hz.

CSN team members Richard Guy and Monica Kohler in front of building prior to the start of seismic testing.