UC San Diego’s earthquake simulator, one of the two biggest shake tables in the world, is scheduled to test the tallest full-scale building ever built on an earthquake simulator.

The NSF-funded outdoor shake table at the University of California San Diego will shake the structure, known as the Tallwood project, this spring. Tallwood is a 10-story, full-scale, cross-laminated timber building to assess seismic safety. 

The shake table can carry and shake structures weighing up to 2000 metric tons, or 4.5 million pounds. This makes it the earthquake simulator capable of carrying the largest payload in the world. It’s also the only large-scale earthquake table in the world located outdoors.  

The tests are scheduled to start in late April. The shake table will simulate earthquake motions recorded during prior earthquakes covering a range of earthquake magnitudes on the Richter scale, from magnitude 4 to magnitude 8, including various iterations of the 6.7 magnitude Northridge earthquake which struck Los Angeles in 1994. This will be done by accelerating the table to at least 1g, which could accelerate the top of the building to as much as 3gs. For reference, on average, modern roller coasters produce 4g of peak acceleration. 

The shake table was upgraded with a $16.9 million grant from NSF. It went from being able to move in one direction – east-west – to three directions – east-west, north-south, up and down, as well as roll, pitch, and yaw, three motions in the x, y, and z axes.

Being able to reproduce earthquake ground motions in six degrees of freedom is important because, during a tremor, the ground doesn’t just shake horizontally in a single direction.