SAN FRANCISCO – The city’s newest hospital will have a unique protection against earthquakes like the one that devastated the city 110 years ago today, or the temblors that rocked Ecuador and Japan in recent days: goo.
The California Pacific Medical Center, set to open in 2020 near City Hall, will have specially designed walls built to sway during a catastrophic earthquake, allowing the facility to stay operational. The walls will be injected with shock-absorbing polyisobutylene, a compound developed in Japan and more commonly used to make soccer balls.
"One of the things we wanted to see was, would we burst them, would we break them? And we couldn't break them."
"As the one floor moves relative to the other floor in the earthquake, it's pushing a vein through this viscous material, absorbing the energy of the earthquake," said Jay Love, of Degenkolb Engineers, the firm heading the $2 billion project.
The Great San Francisco Earthquake and Fire struck on April 18, 1906, killing more than 3,000 people and destroying more than 80 percent of the City by the Bay. Even without events like Saturday’s earthquake that killed at least 350 in Ecuador, San Francisco residents are keenly aware that the next big one could hit anytime. They can only hope new advances in structural engineering will help them survive.
Positioned at intervals throughout the exterior of the 274-bed hospital are 120 burgundy viscous wall dampers filled with the goo. The thick material was heated and then injected into the steel wall panels.
In the event of an earthquake, the facility will sway gently as the jolt is absorbed in the specially lined walls, say experts. Engineers at the University of California San Diego subjected the dampers to the equivalent of a 7.9 temblor -- the same magnitude as the 1906 San Francisco earthquake.
"One of the things we wanted to see was, would we burst them, would we break them?” said Love. “And we couldn't break them."
The steel panels passed every test. And with the San Francisco Bay Area overdue for a major quake, seismologists say advances that make tall buildings safer are critical.
"Anything that can take the energy that is generated from the earthquake and help it dissipate without it causing cracking is a good thing," said Jennifer Strauss, of UC Berkeley Seismology Lab.
The new medical center, located near the famous San Andreas fault, is the first building in the U.S. to utilize this "gooey" technology. If they perform as expected, viscous wall dampers could be the new way to build tall buildings in earthquake zones.