近年來，隨著陸路交通網路日趨活絡，具有高速度、高承載的高鐵系統已是一個國家走向現代化的基本建設。由於一般吊橋的跨度（在百米以上）均遠大於常見的簡支或連續型鐵路橋，且其低階振頻也大都位在低頻範圍。因此，鐵路吊橋因列車行駛而被激起的共振反應，勢必也更容易發生。惟在計算吊橋受車行之動力反應，因要處理的是：非線性偏微分-積分的混合方程式。對以上之運算處理，本文將以不需解聯立非線性方程組的「增量迭代法(incremental-iterative method)」，並配合Newmark 差分計算法則，來進行吊橋的非線性動力反應計算。由本文之研究結果顯示，因吊橋的跨度遠大於序列車輪載間距，因此，當吊橋主梁上有數個輪載通過時，對吊橋的主梁單曲度反應便具有壓制的效果。所以當吊橋受車行引起之最大加速度反應位置，並不一定發生在梁的中跨，其位置與受激發的振態形狀有關。 The rapid advance in construction materials and technologies brings about modern suspension bridges being able to span rivers, valleys, and straits for ground transportation. Since a long span suspension bridge possesses the characteristics of low frequencies, the train-induced resonance phenomenon would be excited one the beam deck. This study models a suspension bridge as a single-span beam suspended by the hangers and hinged at the two ends. The train is simulated as a sequence of equidistant moving loads with identical weights. To compute the response of the suspended beam subjected to moving loads, the governing equation is transformed into the generalized coordinates by Galerkin’s method, and solved by a rigorous incremental-iterative procedure. The results indicate that the critical position for the maximum acceleration of the suspended beam to occur under the moving loads depends upon the modal shape that has been excited, which can be anti-symmetric or symmetric.
Relation:
中華民國第九屆結構工程研討會論文集=Proceedings of The 9th National Conference on Structure Engineering，8頁
