Most people believe buildings codes are designed so that a building can withstand a major earthquake. The fact is that current seismic-safety building codes only aim to ensure human safety, but in the larger scheme of things, it is just as important to design buildings that remain habitable and not displace large amounts of people after a major quake.
As we saw recently in Mexico, buildings collapsed and/or were severely damaged, leaving thousands of people homeless. This is a fresh example of why it is essential for building codes to be geared towards resiliency instead of just life-saving.
Consider the work being done at the University of California-San Diego (UCSD). UCSD has the largest open-air shake table in the world, which is currently being used to test various wood designs for earthquake resiliency. The goal of the tests is to gather enough data to design wood buildings as tall as 20 stories that do not suffer significant damage during large earthquakes. Theoretically, in the future, not only can occupants leave buildings unharmed, but they can return and resume living/working in them shortly after a large quake.
On July 14, a two-story wooden structure was tested using four different earthquake simulations, with no significant damage. The wood is primarily cross-laminated timber (CLT), which is a relatively new, high-performance material made from layers of wood laminate. You can see a video of this test here. By 2020, the team will build and test a 10-story building.
Originally, the shake table was built as a single degree-of-freedom system due to budget limitation, but it was designed to be readily upgradable to 6 degrees-of-freedom. Once it is upgraded to 6 degrees-of-freedom, it will be able to reproduce very accurately the most destructive earthquakes on record and their multi-directional characteristics.
To me, this work is critical because it is bringing us one step closer to more resilient buildings — and an overall more resilient society.
Category: Climate/natural disasters: Earthquakes, Resilience
Location: California, United States