Simpson Strong

Pleasanton, Calif. — Simpson Strong-Tie has announced the successful completion of a series of seismic tests on the tallest building yet subjected to earthquake simulations. Tests on the 10-story mass timber structure were conducted as part of the Natural Hazards Engineering Research Infrastructure (NHERI) TallWood Project, a research project funded by the National Science Foundation and building industry partners to prove the strength and seismic resiliency of mass timber as a low-carbon structural building material.

Seismic tests simulating both the 1994 magnitude 6.7 Northridge earthquake and the 1999 magnitude 7.7 Jiji earthquake were conducted at the Englekirk Structural Engineering Center at the University of California San Diego (UCSD), home to North America's largest outdoor shake table and one of the two biggest earthquake simulators in the world, with a capacity of carrying and shaking structures weighing up to 2,000 metric tons across six axes of movement.

In addition to UCSD, a consortium of universities collaborated on the NHERI TallWood project, including the Colorado School of Mines; the University of Nevada, Reno; Colorado State University; the University of Washington; Washington State University; Oregon State University; and Lehigh University. The project also received support from the U.S. Forest Service and the USDA Forest Products Laboratory.

"Mass timber is part of a massive trend in architecture and construction, but the seismic performance of tall buildings made with these new systems is not as well understood as other existing building systems," says Shiling Pei, principal investigator and associate professor of civil and environmental engineering at Colorado School of Mines.

The 10-story tall building is the tallest full-scale building ever tested on an earthquake simulation shake table, and features a new rocking wall lateral system designed for resilient performance, meaning the building will have minimal damage from design-level earthquakes and be quickly repairable after rare earthquakes.

In 2017, Simpson Strong-Tie collaborated with the project team to test a two-story mass timber building by simulating the Northridge earthquake. In addition to demonstrating that mass timber building systems can be seismically resilient, those tests helped the research team develop the design and analysis methods that were used for the 10-story building. Simpson Strong-Tie also conducts seismic research on earthquake simulators located at the company's Tyrell Gilb research facility in Stockton, California.

"As a pioneer in the development of stronger, more resilient structural systems, Simpson Strong-Tie is excited to partner with the NHERI project team to advance the research of mass timber performance during seismic events," says Steve Pryor, Advanced Research Manager at Simpson Strong-Tie. "These powerful earthquake simulations will help us better understand the resiliency of both structural and safety-critical nonstructural components in mass timber construction, and will help to validate mass timber as a building material for tall structures in seismically prone areas."

During the tests, an array of sensors measured the impact of seismic forces across a variety of building systems. In addition to the rocking wall lateral system, the building features four exterior façade assemblies, a number of interior walls, and a 10-story stair tower.

The full findings of the construction and testing of the building will be published later this year, and are expected to support continued adoption of mass timber as a strong and versatile building material for residential and commercial structures in areas prone to seismic activity.

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