【正文】 he top slab’s thickness is .The second step is to use BSAS software to analyze internal gross force of the structures(including dead load and lived load), the internal force position can be done by using the pute results. According to the internal force posited, the evaluated amount of longitudinal tendons can be worked out, then we can distribute the tendons to the bridge.The third steps is to calculate the loss of prestressing and secondary force due to prestressing, first dead loads and temperature, bearing displacement, and so on.The last steps is checking the main cross section. the work includes the loadcaring capacity ultimate state and the normal service ability ultimate state as well as the main section’s being out of shape.Key Words: Prestressed concrete continuous girder bridge, Secondary force，Cantilever constructed 西南交通大學本科畢業(yè)設計 第 VI 頁目 錄第 1 章 緒論 ........................................................................................................................1 預應力混凝土連續(xù)梁橋概述 ......................................................................................1 畢業(yè)設計的目的與意義 ............................................................................................3第 2 章 橋跨總體布置及結構尺寸擬定 ..............................................................................4 尺寸擬定 ......................................................................................................................4 橋孔分跨 ...............................................................................................................4 截面形式 ...............................................................................................................4 梁高 .......................................................................................................................5 細部尺寸 ...............................................................................................................6 主梁分段與施工階段的劃分 ......................................................................................7 分段原則 ...............................................................................................................7 具體分段 ...............................................................................................................7 主梁施工方法及注意事項 ...................................................................................7第 3 章 荷載內力計算 ........................................................................................................9 恒載內力計算 ..............................................................................................................9 活載內力計算 ............................................................................................................11 橫向分布系數的考慮 .........................................................................................11 活載 因子的計算 .................................................................................................11 計算結果 .............................................................................................................13第 4 章 預應力鋼束的估算與布置 ..................................................................................15 力筋估算 ....................................................................................................................15 計算原理 .............................................................................................................15 預應力鋼束的估算 .............................................................................................18 預應力鋼束的布置 ....................................................................................................24第 5 章 預應力損失及有效應力的計算 ............................................................................26 預應力損失的計算 ....................................................................................................26 西南交通大學本科畢業(yè)設計 第 VII 頁 有效預應力的計算 ....................................................................................................33第 6 章 次內力 的計算 ........................................................................................................35 徐變次內力的計算 ....................................................................................................35 結構重力徐變次內力 .........................................................................................35 預加力徐變次內力 ..............................................................................................38 預加力引起的二次力矩 ............................................................................................40 溫度次內力的計算 ....................................................................................................43第 7 章 內力組合 ................................................................................................................48 承載能力極限狀態(tài)下的效應組合 ..........................................................................48 正常使用極限狀態(tài)下的效應組合 ..........................................................................49第 8 章 主梁截面驗算 ........................................................................................................51 截面強度驗算 ............................................................................................................51 截面抗裂驗算 ............................................................................................................54 正截面和斜截面抗裂驗算 .................................................................................54 法向拉應力 .........................................................................................................55 主拉應力和主壓應力 .........................................................................................56第 9 章 主要工程數量計算 ..............................................................................................61 混凝土總用量計算 ..................................................................................................61 梁體混凝土