Infrastructure protectionNew Bay Area hospital is constructed to withstand the most severe earthquake
The new Stanford Hospital is being constructed to withstand the most severe tremors. The new hospital will be placed on 206 base isolators, enormous parallel steel plates with a sort of ball bearing suspension system between them, providing a buffer between the building and the moving ground. Each plate can move as much as three feet in any direction, allowing the building to shift up to six feet during seismic activity. Reducing horizontal movement during an earthquake minimizes the strain on a building’s vertical load-bearing structures. When completed, in 2017, the building will be one of the most seismically safe hospitals in the country, able to continue operations after an 8.0, or “great,” earthquake.
The odds of a major earthquake occurring in the Bay Area are high. Stanford University is located close to the San Andreas Fault, one of the world’s most active faults, and the Hayward Fault, which has been called a “tectonic time bomb.”
Numerous smaller faults run the length of the Peninsula. The U.S. Geological Survey predicts a 63 percent probability of a 6.7 earthquake within the next twenty years for the Bay Area — similar in magnitude to the quakes that rocked Chile and Japan in March.
A Stanford University release reports, though, that the new Stanford Hospital is being constructed to withstand the most severe tremors. When completed, in 2017, the building will be one of the most seismically safe hospitals in the country, able to continue operations after an 8.0, or “great,” earthquake.
Buffer system
The new hospital will be placed on 206 base isolators, enormous parallel steel plates with a sort of ball bearing suspension system between them, providing a buffer between the building and the moving ground. Each plate can move as much as three feet in any direction, allowing the building to shift up to six feet during seismic activity. Reducing horizontal movement during an earthquake minimizes the strain on a building’s vertical load-bearing structures.
Because the base of the hospital is able to move at the same rate as the shaking ground, the building itself will barely shift.
“During an earthquake, the earth jerks one way and then another — as if you are standing on a carpet that is being pulled back and forth,” said Bert Hurlbut, vice president of construction for the new Stanford Hospital. “But we’re talking about a tremendous force of horizontal acceleration. Since it’s impossible to prevent an earthquake, we’re building structures that keep people safe by dampening the energy and ensuring structural integrity.
Following Southern California’s devastating Northridge earthquake in 1994, the California State Legislature mandated strict seismic safety regulations for facilities that provide emergency or surgical services.
Lucile Packard Children’s Hospital Stanford is incorporating a different but equally efficient system for seismic safety into its expansion project, which will open to patients in 2017.
