本論文研究目的在探討結構與土壤互制在脊背橋鋼索斷裂之影響，主要以單根與 雙根鋼索瞬間斷裂之影響為考慮要項。其基椿之土壤界面採用Bouc-Wen模式，並模擬 遲滯阻尼。最後再檢討鋼索斷裂所產生的動力放大係數值與PTI所建議之動力放大係 數值之安全性。

The objective of this research is to investigate effects of soil-structure interaction on cable rupture of extradosed bridge. A three span extadosed bridge in Taiwan has been served as an illustrated example to insight these effects. The cable rupture scenarios performed in this research include one-cable rupture and two-cable rupture. The soil-structure interaction of bridge foundations is modelling with Winkler foundation Bouc-Wen model is adopted to account for inelastic responses of soil surrounding the piles. The amplification factors of cable rupture are computed with and without soil-structure interaction for comparison.