Mission Accomplished: World’s Largest Quake Test a Massive Success!

A new type of "rocking wall system" promises to improve seismic building standards and could be introduced into US and Japanese building standards.

Sun 18 Feb 24


A 10-storey cross-laminated timber building tested over 100 times as part of the world’s largest seismic test of a timber building has been dubbed “a resounding success.”

Known as “TallWood”, the project saw the first full-scale testing of a new type of rocking wall system, which, according to Professor Shiling Pei, could soon be added to future building codes in both the United States, Japan and global projects via the International Building Code.

According to Professor Pei, rocking walls are self-centred to prevent significant damage during a quake. “Each 3-metre-wide panel spans the tower’s height and is anchored to the world’s largest outdoor shake table via steel rods,” he said.

“These rods control the motion of the walls, allowing them to lift on one edge and compress on the other while rocking,” according to Fionna Samuels, a PhD candidate involved in the study. 

“When the shaking stops, the rods bring the wall’s edge back to being flush with the shake table — equivalent to the foundation. Thus, the building returns to its original vertical position.”

52808749115 126a44ce30 c fotor 20240215231950
Installing the top of the wooden rocking wall before the final tests. (Photo Credit: University of California San Diego)

According to Professor Pei, “the rocking walls didn’t just work; they were a resounding success,” with the experiment almost disappointing – due to its lack of critical failures. “If you’re looking for damage, this is a very boring test,” he said because there was no structural damage despite the building “violently shaking.”

The success is a culmination of almost a decade of work for Professor Pei, who in 2017 led a previous project that tested rocking walls in a wooden two-story building on the same shake table. 

“Theoretically, you can always say, ‘I think that idea will work,’ but this is the first time to see it work in [a] ten-story wood building,” Professor Pei said.

Beyond structural walls, the project also looked at nonstructural components of the build, “for instance, stairs, windows and some exterior walls,” Ms Samiels said, “which are not usually critical to the integrity of a structure, but they’re vital to its livability.”

first ever earthquake simulation in a 10 story mass timber building 3
UC San Diego hosted the tallest full-scale seismic building test on an earthquake simulator. (Photo Credit: University of California San Diego)

“With the overall theme of designing the structure for resilience, we also wanted to consider the resilience of the nonstructural components,” according to Professor Keri Ryan, the project’s chief investigator for nonstructural components and systems. 

“Even if they’re not carrying any of the load, they’re attached to the building in some way, and they have to go along for the ride,” she said.

With that in mind, the team installed different external facades; each tweaked to isolate the wall from the movement of the building in slightly different ways – achieved by connecting the wall to the building’s frame to allow movement.

Essentially, when the structure begins to sway, as designed, the facade can slip past the moving frame rather than be bowed or deformed by the movement.

52807766807 f9126fa74d c fotor 20240215232228
Inside the TallWood tower before the May 9, 2023 testing. (Photo Credit: University of California San Diego)

“The assemblies didn’t all work exactly as expected,” Professor Ryan said, “but they all could accommodate the movement without damage, which was huge.” 

Not only could this kind of technology protect people from falling facades during a quake, “but further research and development may also help keep the building more livable directly after an earthquake,” Ms Samuels said.

This “functional recovery” keeps buildings safe and inhabitable immediately after a seismic event “so that residents are not displaced while any minimal damage the building incurred is repaired.”

According to Professor Ryan, “shaking can cause nearly invisible cracks in windows and walls that break the seal of a building envelope but are not structurally significant.” She said a preliminary study found that although the installed windows appeared undamaged at the end of testing, calculations showed up to 30% loss of air tightness. 

“A window’s movement will likely come down to its manufacturing,” Professor Ryan said, adding that linking the structural and functional performance of buildings’ facades during and after earthquakes will be a fertile ground for future studies.

Footage of TallWood during one of the 100-plus shake tests – footage courtesy of @abc10news.
The future of TallWood

After the final tests in August last year, the four upper levels were removed and handed over to Professor Andre Barbosa from Oregan State University.

Professor Barbosa will lead the NHERI Converging Design Project, using the now six-story TallWood building to test three lateral force-resisting systems

The first is the existing rocking wall system. The next is a new design that only has energy dissipation devices installed on the first floor of the building. The final system will involve adding a specially designed steel frame and brace system to the entire building.

“This project will measure and validate new resilient construction methods and demonstrate the versatility of mass timber structures,” according to Professor Barbosa, who said the data “will help to develop resilient mass timber design solutions across many building heights and types.”


  • Jason Ross

    Jason Ross, publisher, is a 15-year professional in building and construction, connecting with more than 400 specifiers. A Gottstein Fellowship recipient, he is passionate about growing the market for wood-based information. Jason is Wood Central's in-house emcee and is available for corporate host and MC services.


Related Articles