First-of-its-kind test to prove resilience of tall mass timber buildings in seismic events

Practical testing is underway at the University of California San Diego (UCSD) on the tallest building ever to be seismically tested. The building, a 10-storey mass timber structure, was constructed to undergo testing as part of the Natural Hazards Engineering Research Infrastructure (NHERI) TallWood Project, an industry-wide initiative to prove the seismic resilience of mass timber and its strength as a low-carbon structural building material supported by Think Wood, its parent organization the Softwood Lumber Board (SLB), and its partner organizations WoodWorks and the Binational Softwood Lumber Council (BSLC), among others.

The project investigates the capability of tall mass timber buildings to withstand seismic events; a robust university-backed testing process will conduct earthquake simulations to assess the material’s resilience. The project could pave the way for changes in building codes for residential and commercial structures that could lead to more widespread adoption of mass timber as a sustainable, strong, and versatile building material – especially in areas prone to seismic activity. It could also validate mass timber and other innovative technologies as vehicles to help make buildings safer and more resistant to earthquake activity. Findings of the construction and testing of the building will be published this summer and, if deemed repeatable and scalable, could have implications for the broader Architecture, Engineering, and Construction (AEC) industry and the built environment at large.

“Mass timber is already known globally as a sustainable, low-carbon building material,” says Cees de Jager, president and CEO of the SLB and BSLC. “These tests will prove mass timber’s viability as a safe and effective, as well as sustainable, alternative to steel-and-concrete buildings in seismically active areas, paving the way for broader adoption in taller mass timber structures nationwide.”

The principal investigators include researchers from the Colorado School of Mines; the University of Washington; the University of Nevada, Reno; Colorado State University; Washington State University; and Lehigh University. UCSD’s shake table, where the testing is taking place, is the largest outdoor shake table in the world and recently underwent an upgrade that increases the number of axes of shake – better simulating actual seismic events.

The 10-storey structure is made up largely of donated mass timber. “This is the first time a building this tall has been tested on a shake table at full scale, and the test will validate mass timber as a seismically resilient building material for tall structures,” says Shiling Pei, P.E., associate professor in the Department of Civil and Environmental Engineering at the Colorado School of Mines and a principal investigator on the project.

As an early adopter of mass timber construction, Swinerton leads the industry in innovative structures and provides a collaborative approach focusing on constructability and erection logistics. Timberlab, a Swinerton company, led the virtual construction and fabrication of columns, beams, and the deck for the top four levels of the structure, which was designed by LEVER Architecture.

“LEVER has been designing with mass timber for almost 10 years, and we are passionate about building with wood because it is beautiful, sustainable, and connects urban growth to rural economic development,” says Jonathan Heppner, a principal at LEVER. “Projects like NHERI advance the industry’s understanding of mass timber’s capabilities and jurisdictional approvability, so our firm and the design and engineering community can continue innovating with this material, knowing it is seismically safe.”

“This project was an ‘all-hands-on-deck’ approach and speaks to the highly collaborative network of AEC partners who are pushing the boundaries of mass timber construction,” says Brooke Whitsell, a timber engineer at Timberlab. “It has been a rewarding experience to watch this project come together, with each partner equally invested in the seismic potential of wood construction. I envision tall wood structures all along the West Coast, equipped for seismic events as a result of the NHERI research.”

The structure is built from materials provided by partners at wood and building product manufacturers such as Construction Specialties (CS), which offers a broad range of industry solutions including seismically safe, modular stair systems. While extensive testing of the DriftReady stair solutions has already been conducted in the system’s development, the CS team is excited to learn how the whole system performs under seismic duress in a multi-storey application. CS believes that involvement with and learnings from projects like this are invaluable to advancing not only the company’s solutions but also to help the entire marketplace build better buildings to protect people and spaces more effectively.

“Projects like this let us put our solutions and our engineering expertise to the test in a more realistic simulation,” says Kevin Smith, P.E., CWI, senior engineering manager at CS. “As a manufacturing company, we work hard to develop the best-engineered solutions for the needs of the market. Opportunities like this allow us to dig deep and educate ourselves on how our solutions perform with adjacent systems in an earthquake. The ultimate goal is to improve the resilience of the building itself and the components that are critical to life safety.”

The project represents a vast cross-disciplinary partnership that touches on all verticals – from lumber production through mass timber fabrication and from architectural design to engineering and construction in the AEC industry. In addition to those mentioned above – and the primary funder, the National Science Foundation – industry partners also include Simpson Strong-Tie, Sumitomo Forestry, Boise Cascade, the United States Department of Agriculture (USDA), the USDA Forest Products Laboratory, the U.S. Endowment for Forestry and Communities, Freres Lumber, SmartLam, Mass Timber Services, Rex Lumber Company, Idaho Forest Group, and TallWood Design Institute, among others.

While the NHERI project will primarily focus on the seismic capabilities of mass timber, researchers will also be examining mass timber deconstruction. After the initial seismic testing, researchers will disassemble the top four floors and send the deconstructed wood back to Oregon State University for additional testing and research to gather data for end-of-life reuse in the built environment.