摩擦消能水平雙向隔震行為模擬與試驗及雙單向反應極值倍率之研究

Bidirectional Simulation and Experiment on Friction Pendulum Isolation System and Research on Ratio between Bidirectional and Unidirectional Peak Responses

蔡易佑(Yi-Yo Tsai)

指導教授 ： 鍾立來

國立臺灣大學/工學院/土木工程學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201603182

摘要

隔震系統可有效的減少上傳至上部結構之地震力，主要有摩擦滑動隔震系統以及類彈簧隔震系統，最常見的滑動隔震系統為摩擦單擺系統。對於隔震系統之分析，過去的研究已將水平單軸向隔震系統研究透徹，而雙向分析則略顯不足。本文首先介紹一水平雙軸向剛體隔震系統之模擬方法，而此方法有其物理假設。摩擦係數對於摩擦單擺系統乃一重要參數，本文將數值模擬方法分別與定值以及隨速度變化之摩擦係數模型做結合。利用一振動台試驗，由實驗數據檢核模擬方法之假設，以及進行數值模擬結果和實驗結果之比對。最後驗證模擬之準確性與比較兩種摩擦係數模型之優劣，並對兩種模型出建議。
本文利用雙向以及單向模擬方法，以外力輸入為六種真實地震，並利用七種無因次化指標配合正規化尖峰地表加速度繪製出指標圖。探討雙向與單向反應極值間的倍率關係以及觀察水平雙軸向隔震系統之行為。對於雙向合反應極值與單向反應極值之比值，本文皆對加速度與位移給定一保守範圍以利工程師對其分析結果進行檢核，並將其應用於靜力分析上。利用雙向外力輸入為正弦波具相位差進行模擬，可觀察出較先消能之方向其隔震效果較佳。另外，利用外力輸入為真實震波進行模擬，給定兩向尖峰地表加速度之時距為0.25倍隔震週期作為門檻，震波時距小於此門檻則視為震波同時到達。最後利用實驗結果驗證模擬所提出之觀察，對於加速度類指標以及合方向隔震效果，指標參數分析有不錯之精確度。對於隔震雙向行為，實驗結果亦發現較早消能且PGA較大之方向其隔震反應較小以及隔震效果較佳，且隔震系統在兩向尖峰地表加速度發生時距接近的震波下其隔震效果較差。

關鍵字

摩擦單擺隔震系統 ； 水平雙軸向隔震試驗 ； 水平雙軸向隔震模擬與行為 ； 水平單向與雙向隔震反應極值倍率 ； 摩擦係數模型

並列摘要

Seismic isolation is an effective way to reduce seismic force which transmits to superstructure. The most common sliding isolation system is friction pendulum system which (FPS). In isolation system previous research, unidirectional isolation behavior is more thorough than bidirectional isolation behavior. Therefore, we introduce bidirectional isolation simulation of FPS and combine two friction coefficient model. Base on shaking table experiment data, we check the assumption of bidirectional isolation simulation and accuracy of it. We also compare two friction coefficient model and offer some suggestions on them.
By using unidirectional and bidirectional simulation, we plot figures of seven dimensionless parameters and normalized peak ground acceleration (PGA) relation respectively under six different earthquake record. Observe ratio between bidirectional and unidirectional peak responses and bidirectional isolation behavior. In ratio between bidirectional and unidirectional peak responses, we give conservative range of displacement and acceleration. Engineers can not only use the ratio to check their analysis but also utilize in static analysis. In bidirectional isolation behavior, we use input as sine waves that phase between two orthogonal direction is different and earthquake record. to analysis. The sine waves analysis results indicate energy dissipation in leading phase direction is better. According to earthquake record analysis, we determine determine one fourth of isolation period as threshold. If time interval between two orthogonal direction’s PGA arrived less than the threshold, the two orthogonal direction’s PGA arrived regard as at the same time.
Base on shaking table experiment’s results, threre are good accuracy of the dimensionless parameter in acceleration. According to bidirectional experiment’s results, we can find out that isolation displacement and structural acceleration are smaller in direction which PGA happen first then the other direction and isolation effect of isolation building is worse when two orthogonal direction’s PGA arrived regard as at the same time of earthquake.

並列關鍵字

friction pendulum system ； bidirectional isolation experiment ； bidirectional isolation simulation and behavior ； ratio between bidirectional and unidirectional peak responses ； friction coefficient model

參考文獻

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