應用勁度可變式滑動隔震支承於平面曲梁橋之動力分析

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Title:	應用勁度可變式滑動隔震支承於平面曲梁橋之動力分析
Authors:	羅定軒;Lo, Ting-Hsuan
Contributors:	土木工程學系
Keywords:	水平曲梁橋;勁度可變式滑動隔震支承;多項式摩擦單擺支承;近斷層震波;新隱式非線性動力有限元素分析程序;horizontal-curved bridge;Sliding Isolators with Variable Curvature;Polynomial Friction Pendulum Isolator;near-fault ground motion;New Implicit Nilinear Dynamic Finite Element Method
Date:	2023-03-22
Issue Date:	2024-09-19 14:11:31 (UTC+8)
Publisher:	國立中央大學
Abstract:	為改善傳統摩擦單擺支承(FPS)隔震週期易與長週期速度脈衝之近域地震相近而發生共振之缺點，採用勁度可變式滑動隔震支承(Sliding Isolators with Variable Curvature, SIVC)可利用其隔震頻率隨支承位移變化，當勁度遞減時減緩上部結構加速度反應，勁度遞增則降低上部結構位移量，以此避開近斷層震波之共振反應，同時降低橋面版位移，避免伸縮縫碰撞與橋墩P-delta效應，而SIVC中曲盤面為六次方程式之滑動支承稱為多項式摩擦單擺支承(Polynomial Friction Pendulum Isolator, PFPI)，過往研究已證實PFPI對等高度橋墩之規則性橋梁及不等高橋墩之不規則性橋梁，均可發揮變頻特性，於近、遠域震波中皆可發揮隔震效果。然而過去文獻未有將PFPI應用於水平曲梁橋之研究，因此本研究採用新隱式非線性動力有限元素分析程序(NINDFEM)進行數值分析，研究含PFPI單、多跨曲橋上部結構之系統動力行為與特性，即不考量橋墩之影響，除探討曲梁之曲率外，亦研究不同支承配置與震波輸入角度等變化參數，最後將上述單、多跨分析之PFPI支承替換成FPS進行隔震效能比對。研究顯示曲梁曲率半徑越小、震波輸入角度越大，支承反力與大梁內力變化差異越大，而配置不同將造成特定力學行為;兩種支承比較中，PFPI隔震支承位移均遠小於FPS之，表示PFPI亦於水平曲梁橋下有良好的隔震效果。;To improve the defect which the period of Friction pendulum system (FPS) and long-period velocity impulse of near-fault ground motions may cause resonance effect, applying Sliding Isolators with Variable Curvature (SIVC) can solve this problem. Its isolation frequency changed by support’s displacement. When the stiffness of support reduce, the acceletation response of upper structure slow down, on the other hand, the structure’s displacement reduce as stiffness rise. By this property,the structure can avoid the resonant response under near-field excitations. Furthermore, the deck displacement can be decreased to avoiding the collision effect at expansion joints and P-delta effect. In the category of SIVC, sliding bearing which has sextic equation surface is called Polynomial Friction Pendulum Isolator (PFPI). Previous studies have confirmed that PFPI can isolate vibration by varying frequency in near and far-field seismic, also in equal-height, unequal-height, regular and irregular bridge. However previous studies never consider that using PFPI on horizontal-curved bridge. So, this study uses New Implicit Nonlinear Dynamic Finite Element Method (NINDFEM) to analyze horizontal-curve bridge. This study include PFPI’s dynamic behavior and property of upper structure in single and multi-span. Without regard for pier, the study not only consider curvature of cuerved bridge but also discuss the influence of support type and seismic wave input angle. Additionally, compare the seismic respond by alternating PFPI for FPS. It shows that the lower curvature or the bigger seismic wave angle input would make support reaction and girder internal force more changeable. The mechanic would be specific as support’s type change. Comparing PFPI and FPS, PFPI’s displacement is extremely lower than FPS’s displacement. It shows that PFPI can offer better isolate vibration than FPS.
Appears in Collections:	[Graduate Institute of Civil Engineering] Electronic Thesis & Dissertation

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