| Summary: | 碩士 === 國立臺灣科技大學 === 營建工程系 === 94 === Abstract
The excessive displacement demand on the isolation system by long period and/or near field earthquake ground motions is always a concern when designing a seismically isolated structure. If the isolated structure is designed with respective to the demand of maximum considered earthquakes and/or near field earthquakes, the isolation system may not perform effectively well when the isolated structure is subjected to small and moderate earthquakes. Therefore, it is very difficult to design an isolation system that will perform effectively across small, moderate and major earthquakes (or call it all purpose isolation system, APIS).
It has been recognized that to include viscous dampers in an isolation system is an effective method to control the displacement response without dramatically increasing the transmitted force of the isolation system. This is due to the existence of a phase lag between the damper force and damper displacement while most of isolation bearings such as lead-rubber bearings has an in-phase behavior between their force and displacement. In this study, analytical study is conducted to study the significance of damping exponent and in an isolation system composed of viscous dampers and lead-rubber bearings. Conceptually, the purpose for adopting the so far never-used (in civil engineering structures) viscous dampers with is to fulfill the requirement of an APIS. This is because the viscous damper is an redundant when the isolated structure is subjected to small and moderate earthquakes, and is efficiently effective while major earthquakes strike.
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