本研究探討橋梁受複合式災害,即河床沖刷與地震來襲相繼威脅,因樁基礎裸露對耐震性能之影響,使用大型雙軸向剪力試驗盒,進行單柱橋梁樁基礎沖刷裸露之振動台實驗。實驗試體採用單自由度單柱橋梁、單樁基礎與乾性石英砂質土壤。實驗規劃數組不同基樁裸露長度之組別,以觀察地震作用下之樁土互制行為。爾後再利用SAP2000分析軟體,參採公路橋梁耐震設計規範,建立樁土互制模型,比較實驗值與分析值的差異。本研究對於土壤彈簧之勁度、設定位置及系統阻尼比的設置,提出一些改進的方式。最後將工程界普遍採用之分析方法,與本研究之分析方法,做一綜合比較,以期未來能將本研究內容應用至橋梁監測系統及橋梁基礎耐震補強工作。
This study presented the shaking table tests results of a scoured bridge-pile system carried out in National Center for Research on Earthquake Engineering (NCREE) through a bilateral laminated sand box. The experimental program was characterized by the scouring depth regarding to the diameter D of the pile. The time history results in each case were compared with those obtained from simplified analytical models with linear soil springs. New methods used in the analytical models include the modified locations of soil springs, the calculation of shear wave velocity of soil, and so on. The simulation results of acceleration and displacement are well satisfied with the test data earthquake excitations under 200 gals, particularly at the mass center of the single-degree-of freedom bridge system. It is expected to effectively predict the dynamic response of the scoured bridge with soil-structure-interaction issue.