本研究目的以彈簧與阻尼為基本元件，並以開孔元素模擬不工作長度，探討各種不同組合之防落裝置效用以及與橋梁結構間之互制行為，另外亦討論隔震橋梁增設阻尼器之消能效用，藉由廣泛之參數分析，求得最佳之設計參數並建立設計圖表供參考，設計參數包含橋梁周期、兩相鄰橋梁周期比、彈簧勁度值、阻尼係數、防落裝置不工作長度與阻尼比等。 強震下橋梁結構部分構件已進入非線性行為，因此本研究以非線性動力分析為主，建立非線性分析模型，非線性構件包含支承、柱底塑鉸、防落裝置等，為大量參數分析，亦建立簡化數值分析模型，以節省分析時間，可更完整地探討各參數對橋梁動態反應之影響。 由分析結果顯示，防落裝置型式愈接近純阻尼元素，且於適當的不工作長度下，有助於降低橋梁結構動力反應；連結於上部結構與橋墩之阻尼器安裝於第一振態自然周期小於1.2秒之橋梁結構，其消能能力不佳，因此自然周期大於1.2秒之橋梁配置適當阻尼，降低橋梁動力反應情形較佳。 The objective of this study is to determine the effects of varied unseating prevention devices consists of springs, dampers and hook/gap elements simulated the workless length and the interactive behavior between these devices and whole bridges, in addition, the effects of energy dissipating dampers installed within isolated bridges are observed. According to general numerical analysis, it is defined as ideal design parameters and constructed design diagrams. The design parameters include period, period ratio between two vibration units, stiffness, damping coefficient, workless length, damping ratio and so on. The partial components of bridges obtain nonlinear behavior during the strong ground motion, so this study is based on the nonlinear dynamic analysis building nonlinear analytic models. The nonlinear components include isolated bearing, plastic hinge and unseating prevention device, etc. The simplified models of bridges to a large amount of numerical analysis are established so that reducing the time cost and discussing the effects of varied parameters based on dynamic responses completely. Analytic results show that the type of unseating prevention devices approximate the damper element within the suitable workless length, it is able to reduce dynamic responses. As the dampers between superstructures and piers are installed within bridges whose natural period of the first mode is less than 1.2 seconds, they are helpless to dissipate energy. When the natural period is more than 1.2 seconds, it is suitable using dampers to reducing dynamic responses.
