槓桿式半主動隔震系統於近域防震之應用

A Leverage-Type Semi-Active Isolation System for Seismic Structures in Near-Fault Regions

盧煉元(Lyan-Ywan Lu) ； 許朝畯(Chao-Chun Hsu) ； 葉士瑋(Shih-Wei Yeh)

《中國土木水利工程學刊》 21卷3期 (2009/09) Pp. 319-338

https://doi.org/10.6652/JoCICHE.200909_21(3).0008

摘要

傳統滑動隔震支承於一般震波中雖具有優異之減震效能，但在含有長週期成份的震波中（例如近斷層震波）則易發生低頻似共振現象，造成支承位移過大與隔震效果不彰等問題。為改善此一問題，本文提出一半主動隔震系統稱之為槓桿式勁度可控隔震系統（簡稱LSCIS）。該系統係利用槓桿原理，透過改變槓桿支點位置之方式以達到即時改變隔震系統勁度與隔震週期之目的。由於LSCIS之隔震勁度可隨隔震結構當時之震動反應而適時調整，故該系統較被動式隔震系統具有較佳之可控性，因而可避開低頻震波對隔震系統所產生之不良影響。本文數值模擬結果顯示，不論是在一般震波或長週期震波作用下，槓桿式勁度可控隔震系統之減震效能皆優於傳統被動式滑動隔震系統。

關鍵字

隔震技術 ； 半主動控制 ； 槓桿原理 ； 可變勁度 ； 近斷層震波

並列摘要

Although a conventional passive isolation system may effectively mitigate the dynamic response of a seismic structure in an usual earthquake, it may also encounter a low-frequency resonance problem when subjected to a near-fault earthquake that usually possesses a long-period pulse-like waveform. This long-period wave component may result in an excessive of the isolator displacement and decrease isolation efficiency. To overcome this problem, a semi-active sliding isolation system called Leverage-type Stiffness Controllable Isolation System (LSCIS) is proposed in this study. By varying the ratio of the leverage arm of the LSCIS, the isolation stiffness of the LSCIS system can be controlled by a proposed semi-active control method. So, the system is more controllable than a passive isolation system. The result of numerical simulation has shown that the proposed system is able to effectively mitigate the resonance problem induced by a near-fault earthquake. As a result, that the base displacement and superstructure acceleration of the isolated structure can be reduced simultaneously, as compared to a conventional isolation system.

並列關鍵字

seismic isolation ； semi-active control ； leverage type ； stiffness variable ； near-fault earthquake