以反應譜法分析隔震建物內之次結構的動力反應

Abstract

台灣位處於環太平洋地震帶上，經常發生地震，結構物內重要設備物的耐震設計是相當必要的，如半導體產業之晶圓廠、核能電廠之核子反應爐等工業廠房，一旦地震損壞了次結構繼續運作之能力，將對於社會產業造成極大的損害與衝擊。 過往對於次結構動力分析所採用的方法，不是需要耗費大量的電腦運算時間，就是忽略了主結構與次結構合成系統的固有特性。因此本文首先針對主、次結構合成系統利用狀態空間原理推導出可運用於複數形式的振態疊加法則，並將該法延伸至反應譜方法，提供更為簡便且省時的方法供工程師使用。分析主、次結構合成系統時，需考慮兩者間互制、協調與非比例阻尼等相互影響因素，而當主結構或次結構含有偏心時，又會受到扭轉效應之影響，故內文推導出兩種快速解得主結構與次結構合成系統之振態近似解分析模式，分別為簡化修正法與廣義修正法兩式與直接解振態相比有較省時之優點。 本文最後探討於建築物基礎下部設置隔震層之合成系統分析方法。對一含基底隔震層之主、次結構合成系統，其模態解可依循僅考慮二個子系統時的觀念，分為兩階段進行模態修正，第一階段為含隔震層之主結構部份的振態特性，第二階段再將次結構與含有隔震層之主結構部份進行全面性的系統模態修正，如此將可不必再使用數值分析，即能快速解得含隔震層之次結構的近似振態解。

This paper utilizes complex modal analysis technique to deal with a non-proportional damping composite system, which consists of a primary and a secondary systems. The outcome is presented by a response spectrum which is more convenient in the application of design. The interaction, tuning and non-classical damping between sub-systems must be taken into account in the structural analysis of a composite system. In addition, when the structures contain eccentricity, the torsional effect has to be evaluated in the analytical model. The present study obtains the modal characteristics of the composite system by simple modified method and general modified method. These methods offer a less numerical labor than the ordinary one. In regard to a base-isolated composite system, the study focuses on each individual sub-system and modifies the modal shapes by two phases. First, a system involving only the primary structure and its base isolation is analyzed. Then, it goes to the modification of the whole system which includes the secondary system. By using so, the analytical complexity is reduced substantially.