橋梁在平時為重要之交通動脈，在地震發生後尤其是救災行動成功與否之關鍵。然而由於橋梁耐震設計規範之訂立經過多次之修正，現存之橋梁新舊並存，在多次大震災中仍可見到此等結構嚴重受損，因此可見橋梁結構耐震能力評估之迫切需要性。 本研究採用非線性靜力分析之側推法(Push－Over Method )針對橋梁之耐震能力進行詳細評估，分析流程將原來針對房屋結構物非線性耐震分析之ATC40與FEMA273所建議之標準程序依相關規範調整，改良應用於橋梁結構中。經參數分析發現，使用側推法於橋梁結構耐震能力評估之塑鉸抗力性質假設與施加側向力型式對分析結果有重大影響。 文中建議：對於構件塑鉸抗力性質假選擇Caltrans或AASHTO之格式較適用於橋梁耐震能力評估；且須經動力振態計算，適當考量各振態對橋體結構反應之參予程度以決定施加側向力型式。本文並提出振態型式側向分佈力－結構體變形曲線疊代過程更新橋梁整體容量曲線，以彌補線彈性振態計算於反應非線性動力行為之不足。 文末提出使用側推法於決定最小設計水平地震力總橫力V之應用，與現行台灣公路橋梁設計規範結合，希望提供工程界參考依據。 With the growing awareness and concern of the seismic risk, there is a need for efficient and reliable tools for seismic,therefore it is worth to devise a simplified computer method for seismic performance evaluation of structures, pushover analysis is competent for this purpose. For many cases, we can obtain more important information from pushover analysis than dynamic analysis, and it is simple and economical. A method for the nonlinear static analysis of bridge structure is presented, suitable for seismic assessment procedures based on push-over analyses. As the seismic response of buildings is different from the seismic response of bridge structures, the applicability of the push-over analysis for bridge structures has to be investigated specifically.In this paper, a lateral load pattern is taken as the approximation of the distribution of the inertia force obtained from results of dynamic analysis of the MDOF system of the structure, and choice the siutable hinge properties for bridge component. A simple example of the assessment procedure on a 22-spans R.C. bridge structure is presented and future developments are pointed out.
