The base-isolated building retains its original, rectangular shape. The base isolated building itself escapes the deformation and damage-which implies that the inertial forces acting on the base isolated building have been reduced. Experiments and observations of base-isolated buildings in earthquakes to as little as ¼ of the acceleration of comparable fixed-base buildings.
Acceleration is decreased because the base isolation system lengthens a buildings period of vibration, the time it takes for a building to rock back and forth and then back again. And in general, structures with longer periods of vibration tend to reduce acceleration, while those with shorter periods tend to increase or amplify acceleration.
|Mackay School of Mines, University of Nevada - Reno, Nevada (retrofit)|
|Los Angeles City Hall, California (retrofit)|
|Los Angeles County Fire Command & Control Facility, California|
|Foothill Communities Law & Justice Center, County of San Bernardino, California|
|San Francisco City Hall, California (retrofit)|