應用凸面導軌於偏心滾動隔震系統之研究

Abstract

在世界各地，為了減低地震對建築物造成的損害，結構隔震系統已被廣泛的應用在土木工程領域。傳統隔震器如摩擦單擺支承具有線性回復力，在本文中稱之為線性隔震系統。當線性隔震系統遇到同樣具有低頻特性之近斷層地震，可能產生共振效應並導致隔震系統失效。因此，本研究提出一具有非線性回復力之改良型隔震系統。此系統考慮隔震標的物以梢接並偏心於圓形隔震器上，消能裝置為摩擦墊片，此外，在圓形隔震器下方有凸面導軌。首先藉由運動方程式推導建立數學模型，再以參數敏感度分析與自由振動掌握系統之非線性特性。接著，以調控遠域與近斷層地震之PGA來驗證此系統在設備隔震的可行性，藉由模擬分析結果可得此系統在近斷層地震作用之下，相較於線性系統能有效降低加速度反應。而不論在遠域或近斷層地震作用下，其位移反應皆比未含凸面導軌之系統小。在結構隔震應用方面，考慮遠域與近斷層地震作用之下，利用上部結構勁度、質量與摩擦阻尼係數之變異性來探討其性能之變化並驗證本研究提出之改良型隔震系統之可行性。此外，由分析結果可得，相較於未含凸面導軌之系統，應用凸面導軌能在保有良好隔震效果情況下有效降低垂直向之隔震器尺寸，進而增加實務應用上之可行性。

To mitigate the damage on structures caused by earthquakes, the seismic isolation systems have been applied widely in the field of civil engineering. In this study, conventional isolation bearing such as Friction Pendulum Bearing (FPB) is called linear isolation system due to the linear restoring force. However, when subjected to near-fault earthquakes, the linear isolation systems may fail due to resonance. Thus, an Eccentric Rolling Isolation System with Convex Guide (CERIS) possessing a nonlinear restoring force is proposed. The CERIS is composed of a circular isolator with a convex guide and a friction damper. The isolated object is pin connected by a rigid link on the circular isolator eccentrically. First, the equation of motion of CERIS is derived. Then, the nonlinear characteristics of CERIS are grasped by free vibration and sensitivity studies. After that, the feasibility of CERIS applied in equipment isolation is verified by numerical simulations. From the simulation results, comparing to the linear system, CERIS is more effective in reducing the acceleration response. Besides, under far-field and near-fault earthquakes, the displacement responses of CERIS are less than ERIS which is the same nonlinear isolation system but without a convex guide. On the other hand, the feasibility of CERIS applied in structural isolation is proved by studying the performances considering the deviation of the structural stiffness, the structural mass, and the friction coefficient under far-field and near-fault earthquakes. Furthermore, based on the simulation results, applying a convex guide in ERIS can effectively reduce the vertical dimension of the isolator while keeping effective in seismic isolation. In this case, compared to ERIS, CERIS can improve the practicability.