SAFETY EVALUATION OF SEISMICALLY ISOLATED HOUSES WITH DISPLACEMENT RESTRAINT DEVICES UNDER SEVERE EARTHQUAKE MOTIONS

摘要

Recently earthquake ground motions with large amplitude and/or long period component act on seismically isolated buildings. In case of family houses, responses of isolated layers will probably exceed design limitation of isolators during severe earthquakes. To keep a function of isolation during a main- and after-shocks, the isolator should be protected from failure through adding to kinds of shock absorbing devices. To investigate effects of the devices for the reduction of displacement responses of isolators, and influences on the responses of superstructures, a numerical calculation is conducted. A relationship between responses of superstructure and isolator is summarized through several parametric studies on kinds of earthquake motions and operating positions of shock absorbing devices. It is made clear that the response of superstructures is evaluated based on the relative velocity of isolators at the operating position and the controlled displacement of isolated layer.