Comparison of Design Method of Wall Pier and Bent Bridge Based on Minimum Cost from Scouring and Seismic Viewpoint

橋梁耐震設計規範規定當地震發生時無論有無基礎裸露，橋梁基礎勢必要保持彈性，但此方法對於壁式與構架式新建橋梁設計而言並非相當經濟。因此本研究將以兩種方法設計橋梁，第一種方法是以橋梁耐震設計規範之靜力分析法進行壁式與構架式橋梁之設計，第二種方法則以載種組合對於橋梁下部結構基樁做設計，且依循規範將基樁加以圍束，並允許樁頂產生塑鉸。爾後將以上二種方法所設計之橋梁利用容量震譜法進行耐震能力之評估，最後再進行災損分析，求得新建橋梁一年內之總支出再加以比較。 本研究將以容量震譜法求得不同沖刷深度下之耐震能力，並將地震損壞分為無損壞、輕微損壞、中度損壞、嚴重損壞與完全損壞，再配合壁式與構架式橋梁耐震能力的變異係數，求出各地表加速度下，發生各級破壞的或然率。並以不同地表加速度對應之年超越機率曲線模擬橋址之地震危害度曲線。而各級損壞的修復費用，將以佔結構新建成本的比例，即損失比來計算。然而考慮橋梁於一年內的裸露深度為一隨機變數，因此將建立一裸露深度或然率分布曲線進行災損分析，最終比較二種方法之經濟性。The Seismic Design Specifications for Highway Bridges specifies that the pier of the bridge must maintain its’ elasticity during an earthquake. However, this method is not very cost effective for wall pier bridges and bent bridges. Therefore, the study will provide two methods of bridge design. The first method is to implement static analysis according to the Seismic Design Specifications in designing wall piers and bent bridges. The second method is by load combination in designing the pile of bridge substructures. Increasing the stirrup allows the plastic hinge to occur at the top of the pile. Then by using the Capacity Spectrum Analysis (CSA) the designer can determine the method’s aseismatic capability and damage analysis. This creates a comparison of the two methods This study uses CSA to determine the seismic capability of different depths of base plane. The earthquake damage is divided into sections ranging from no damage, slight damage, moderate damage, extensive damage, and complete damage. Moreover, this study also uses the Coefficient of Variation (CV) of the seismic capability to calculate the incidence of each damage levels on Peak Ground Acceleration (PGA). Using the annual excess probability curve to correspond with the different PGA will simulate the seismic hazard curve based on the location of the bridge. The repair expenses of all of the levels will be calculated as a percentage of the cost of the new bridge. A probability curve is established in the exposed depth of the bridge location in order to begin the damage analysis. The probability curve uses the exposed depth in a year as a random variable. This report will compare the efficiencies of the two methods.誌謝..................................................................i要................................................................iii文摘要............................................................iv錄................................................................v目錄..............................................................x圖目錄............................................................xiii一章 緒論..........................................................1 1.1 研究動機與目的...............................................1 1.2 文獻回顧.....................................................3 1.3 本文內容.....................................................4二章 耐震能力評估方法之理論與程序..................................5 2.1耐震能力評估與橋梁結構設計.............................5 2.1.1耐震能力評估分析之方法與流程.... ........................5 2.1.2壁式與構架式橋梁耐震設計...............................6 2.2 柱底之強度與韌性.............................................7 2.2.1 柱底之彎矩降服強度與其所對應之地表加速度...............7 2.2.2 韌性容量之修正.........................................8 2.2.3 實心柱之剪力強度......................................10 2.3 基礎之強度與穩定性..........................................12 2.4 等值土壤彈簧................................................13 2.4.1 水平等值土壤彈簧......................................13 2.4.2 垂直等值土壤彈簧......................................13 2.4.3 土壤之極限承載力......................................14 2.5 耐震設計之靜力分析方法......................................15 2.5.1 設計總橫力............................................15 2.5.2 工址短週期與一秒週期水平譜加速度係數..................17 2.5.3 各類地盤工址短週期與一秒週期水平譜加速度係數..........18 2.5.4 工址設計之最大考量水平譜加速度係數....................19 2.5.5 橋梁振動單元之基本振動週期............................20 2.5.6 台北盆地之工址設計與最大考量水平譜加速度係數..........20 2.5.7 起始降伏地震力放大倍數與結構系統地震力折減係數........20 2.5.8 用途係數..............................................21 2.5.9 地震力之分佈..........................................21 2.5.10 最小水平地震力與最大考量地震之設計地震力.............21 2.6 容量震譜法求結構物之耐震能力................................22 2.6.1 側推分析求結構物之容量曲線(Capacity Curve).............23 2.6.2 建立結構物的容量譜曲線(Capacity Spectrum) ............23 2.6.3 容量譜曲線上任一性能點之週期與阻尼比..................24 2.6.4 阻尼比異於5％之修正係數...............................26 2.6.5 任一性能點對應地表加速度之計算........................26 2.7 破壞模式的介紹與塑鉸特性的假設..............................27 2.7.1 彎矩塑鉸之介紹........................................28 2.7.2 三種破壞模式的介紹....................................29 2.7.2.1 韌性充分發揮之塑鉸特性..........................30 2.7.2.2 斷面韌性部分發揮後產生剪力破壞時之塑鉸特性......30 2.7.2.3 斷面韌性尚未發揮即產生剪力破壞時之塑鉸特性......31 2.7.3 FEMA-273建議之塑鉸特性.................................32三章 災損分析之理論與程序.........................................34 3.1 易損性曲線之概述............................................34 3.1.1 易損性曲線之求取方法..................................35 3.1.2 橋梁分類..............................................36 3.1.3 損壞狀態之定義........................................36 3.1.4 易損性曲線之建立......................................37 3.2 危害度曲線之概述............................................38 3.3 裸露深度或然率分布曲線之概述.................................40 3.4 總經費計算..................................................40 3.4.1 災損分析金額..........................................40 3.4.2 總經費計算............................................41四章 設計例分析...................................................42 4.1 構架式橋梁設計例............................................42 4.1.1 構架式橋梁Case 1之設計例..............................42 4.1.1.1 設計例橋梁之相關假定參數........................42 4.1.1.2 設計例於商用軟體中之模擬........................43 4.1.1.3 構架式橋Case 1設計例於裸露深度0m時之分析結果...43 4.1.1.4 構架式橋Case 1設計例於裸露深度1.5m時之分析結果.46 4.1.1.5 構架式橋Case 1設計例於裸露深3m時之分析結果...47 4.1.1.6 構架式橋Case 1設計例於裸露深度4.5m時之分析結果.48 4.1.1.7 構架式橋Case 1設計例於裸露深度6m時之分析結果...48 4.1.1.8 構架式橋Case 1設計例於裸露深度7.5m時之分析結果.48 4.1.1.9 構架式橋Case 1設計例於裸露深度9m時之分析結果...48 4.1.1.10 小結...........................................49 4.1.2 構架式橋梁Case 2之設計例..............................49 4.1.2.1 構架式橋Case 2設計例於裸露深度0m時之分析結果...50 4.1.2.2 構架式橋Case 2設計例於裸露深度1.5m時之分析結果.50 4.1.2.3 構架式橋Case 2設計例於裸露深3m時之分析結果...50 4.1.2.4 構架式橋Case 2設計例於裸露深度4.5m時之分析結果.51 4.1.2.5 構架式橋Case 2設計例於裸露深度6m時之分析結果...51 4.1.2.6 構架式橋Case 2設計例於裸露深度7.5m時之分析結果.51 4.1.2.7 構架式橋Case 2設計例於裸露深度9m時之分析結果...51 4.1.3 小結..................................................51 4.1.4 構架式橋梁災損分析計算................................52 4.1.4.1 易損性曲線之建立................................52 4.1.4.2 危害度曲線之建立................................52 4.1.4.3 裸露深度或然率分布曲線之建立.....................53 4.1.4.4 災損分析........................................53 4.1.5 新建與修復費用計算....................................53 4.1.5.1 小結............................................54 4.2 壁式橋梁設計例..............................................54 4.2.1 壁式橋墩Case 1之設計例................................55.2.2 壁式橋墩Case 2之設計例................................55.2.3 小結..................................................55.2.4 壁式橋梁災損分析計算..................................56.2.4.1 易損性曲線之建立................................56.2.4.2 危害度曲線之建立................................56.2.4.3 裸露深度或然率分布曲線之建立.....................56.2.4.4 災損分析........................................56 4.2.5 新建與修復費用計算....................................57 4.2.5.1 小結............................................57五章 結論與未來展望...............................................58 5.1 結論........................................................58 5.2 未來展望....................................................59考文獻............................................................6