傳統滑動隔震支承雖對於一般遠域震波有不錯隔震效果，但對於近斷層震波則易造成低頻共振現象，降低減震效果。為改善此問題，本文採用具有變頻特性之多項式摩擦單擺支承(Polynomial Friction Pendulum System, PFPI)為橋梁隔震支承。PFPI為滑動隔震支承，其曲面函數為六次多項式，經由多項式係數變化，可使支承有不同隔震效果：軟化段和硬化段。軟化段作用為降低結構物加速度反應；硬化段則是降低結構物位移反應。 根據前人研究已證實PFPI對於建築物有良好隔震效果，然而其尚未有應用於橋梁隔震之實例。本文採用PFPI為橋梁隔震支承，對其展開一系列研究：(1)以實驗驗證PFPI隔震橋理論之正確性、(2)使用PSO-SA混和搜尋法搜尋支承設計最佳參數，(3)根據日本道路橋示方書建立一座橋梁模型，以PFPI與傳統摩擦單擺支承(Friction Pendulum System, FPS)為隔震支承，比較兩支承隔震效益。研究結果顯示，PFPI較FPS有良好隔震效果，且由於PFPI多功特性(軟化與硬化)，吾人可依據實際需求設計支承隔震行為。 Conventional sliding isolators may be effective when the structures are subjected to far-field ground motions, but it may not be effective when the structures are subjected to near-field ground motions because the pulse periods of the near-field ground motions are usually close to the isolation periods of the isolators, and it may lead isolated structures to resonate with the ground motions. In order to improve the performance of seismic isolation under near-field ground motions, a various frequency isolator which is named Polynomial Friction Pendulum System (PFPI) is used in this study. The sliding surface of PFPI consists of six-order polynomial. The restoring stiffness possesses two sections: softening section and hardening section. The structural acceleration response can be reduced by decreasing the restoring stiffness, while the structural displacement response can be reduced by increasing the restoring stiffness of PFPI. Both theoretical and experimental studies were carried out in this thesis which includes: (1) A shaking table test for simplified isolated bridge model by using PFPI; (2) find out the optimal parameters of PFPI by using PSO-SA hybrid algorithm; (3) compare the isolation effectiveness between PFPI and Friction Pendulum System (FPS). The results show that PFPI has better performance than FPS. Because the multi-function of PFPI (softening section and hardening section), it offers us different choices to do a design.
