隔震支承雖可降低橋梁所引致之地震力，但於強震中上部結構可能產生相當大之位移反應，本研究提出改良式滑模變控制演算法於非線性隔震橋梁之結構控制，並藉由分析模擬來探討規則性隔震橋梁在大地震作用下滑模變控制演算法之有效性，結果顯示相較於傳統LQR最佳控制法及被動控制，滑模變控制演算法在適當的滑模面下能達到較佳的控制效果。此外，研究成果亦證實運用變黏滯阻尼器為半主動控制裝置時，可達到接近於主動控制之控制成效。橋梁由於受地形與線型高程之影響，橋墩經常有不等高之情形，因不等高橋墩之勁度不同，導致各橋墩所受之地震力與結構反應會有所差異。本研究以數值模擬分析探討採用滑模變結構控制演算法於不等高橋墩隔震橋梁之減震效果。由於不等高橋墩隔震橋梁為多自由度結構系統，決定滑模面所需之參數值較多，不易以參數分析法求得最佳之滑模面，本研究採用且改良PSO-SA （particle swarm optimization-simulated annealing）混合搜尋法來求取結構之最佳滑模面，並與參數分析法所得結果比較，數值分析結果證實滑模變結構控制演算法以改良的PSO-SA混合搜尋法求取最佳滑模面，能有效控制不等高橋墩隔震橋梁之地震位移反應。此外，本研究使用磁流變消能器與改良式滑模變結構控制演算法進行一系列的振動台實驗，探討半主動控制系統實際應用時之相關問題，採用一座雙層剪力構架模型及一座以滾動單擺系統作為隔震支承之不等高隔震結構分別模擬規則及不規則隔震橋梁的動力行為，振動台試驗結果顯示無論結構為線性行為或非線性行為，皆有良好的位移反應控制，驗證以改良式滑模變結構控制演算法計算控制力，且用磁流變消能器作為控制裝置之半主動控制系統半主動控制系統可有效地實際應用於非線性隔震橋梁。An alternative design method of sliding mode control is proposed for practical implementation on nonlinear isolated bridges in this study. The proposed controller explicitly reveals the robustness of sliding mode control to parametric uncertainties of structures. The effectiveness of sliding mode control is studied numerically and systematically for an isolated viaduct under extreme earthquakes. The results show that the sliding mode control with appropriate sliding surfaces, obtained by parametric study, achieves outstanding control performance compared to the conventional LQR control and viscous damping passive control. Additionally, the performance of active control can be considerably fulfilled by the semi-active control with variable dampers using the proposed control algorithm.Compared with typical isolated bridges, the irregular isolated bridge has more poles of sliding surface, which dominates the dynamic characteristics of the controlled system and should be determined for the sliding mode control. The effectiveness of sliding mode control on the seismic response of an isolated bridge with columns of irregular heights, which exhibit hysteretic behaviors at both the columns and isolators, is studied. However, because many parameters of sliding surface for the irregular isolated bridge should be determined, it is difficult to find the optimum parameters efficiently and comprehensively by parametric study. The particle swarm optimization-simulated annealing (PSO-SA) hybrid searching algorithm which is an optimization technique, is employed, modified and shown to outperform the particle swarm optimization algorithm and a parametric approach in finding the best sliding surface. Numerical simulations reveal that the sliding mode control together with the modified PSO-SA hybrid searching algorithm provides a simple and powerful technique for more effectively controlling the nonlinear seismic responses of the irregular isolated bridge.A series of shaking table tests were conducted to study the semi-active control with MR dampers for the isolated bridges. A two-story shear-type structure assembled by steel plates and rolled shapes and an isolated structure with columns of irregular heights assembled by steel plates and two pairs of RPS on the top of both columns are designed to simulate the behavior of typical and irregular isolated bridge. The feasibility of the semi-active control system with a MR damper commanded by the continuous sliding mode control algorithm is verified in practical implementations for structures undergoing elastic or inelastic behavior to ground motions.
