本研究採用新近發展之隱式Newmark-β結構動力分析方法，適用於處理大變形、大變位、材料非線性與剛體運動等問題，內容分為兩部分。第一部分配合載重控制與位移控制驗證平面梁元素於高度幾何非線性下分析之能力。 第二部分為橋梁樁基礎之設計法與範例研究目前國內對於樁基礎之設計方法雖已考慮新版設計地震力，但仍採用早期樁基礎之分析設計方法，無法反應整體基礎的邊界條件與互制行為。因此，本研究以國內實際橋梁設計案例，參考日本道路橋示方書有關樁基礎設計規定，使用平面梁元素建立含樁基礎橋墩之分析模型，進行非線性靜力分析。軟弱地盤於地震下土壤易進入塑性，以其分析結果進行檢核設計，經比較，目前國內樁基礎之分析設計法有低估之情形。希冀本研究成果可提供國內橋梁工程師另一可遵循之設計方法。 ;This study is divided into two parts. In the first part, The Implicit time integration method(Newmark-β), a new computational method is adopted in this study because the The Implicit time integration method(Newmark-β) has the superior in managing the engineering problems with material nonlinearity, discontinuity, large deformation and arbitrary rigid body motions of deformable bodies. With Newton-Raphson method and displacement-controlled method, we are able to test ability of planar beam elements at highly geometrically nonlinear analysis. The second part is about pile foundations. Although the seismic design forces of pile foundations have updated based on the current seismic design codes, the analysis method of pile foundations has not yet modified. The current analysis method cannot consider the real boundary conditions and soil-structure interaction. Therefore, in this project the static nonlinear analysis method proposed in the Japan Highway Bridge Design Code is adopted by establishing an analytical model consisting of footing and piles. Through analysis and design by using this model, it is found that if the soil condition is classified soft, the required reinforcement of the piles by current analysis method is underestimated as compared to that by the analytical model. The analysis method in Japan may be considered an alternative method for the pile design.