某跨海大橋3×30米預應力連續(xù)梁橋預應力鋼束的設計計算案例目錄TOC\o"1-3"\h\u23965某跨海大橋3×30米預應力連續(xù)梁橋預應力鋼束的設計計算案例 1308261.1預應力鋼束面積的估算 1265321.2預應力鋼束的布置 3119721.2.1預應力鋼束的布置原則 3245581.2.2預應力鋼束的布置 3107521.3模擬預應力鋼束 680731.4鋼束的預應力損失 8159711.5預應力次內(nèi)力計算 11131631.6普通鋼筋的配置 111.1預應力鋼束面積的估算在分析Midas橋梁模型的基礎上，確定了PSC設計參數(shù)、設計材料、輸出位置和裂縫寬度系數(shù)，并進行了設計梁的設計。在結(jié)果欄上，可以看到預應力筋的估算。其結(jié)果是截面上下邊緣的最小配束。控制部分預應力筋的估計數(shù)量見表1.1。表1.1控制截面預應力鋼筋量估算單元位置頂/底Mg1(kN·m)Msum(kN·m)Mj(kN·m)ey(m)Ny(kN)Ay(m^2)1J[2]底-18.3910-24.8038-24.8038-0.53850.00000.00001J[2]頂-1584.8423-311.0632-1934.79740.20291896.86010.00159J[10]底14087.099520796.631625678.9520-0.766825171.45790.02039J[10]頂61.265711961.4960-3316.90720.45223251.87170.002716J[17]底14691.080723187.983328348.6424-0.842627792.81940.022416J[17]頂-79.380610660.2327413.85830.44960.00000.000023J[24]底4737.896411904.565814004.3100-0.794313729.73190.011123J[24]頂48.6980-1136.3602-2609.93900.29142558.76670.002032J[33]底-182.7061-8503.25734301.7449-0.82484217.39700.003432J[33]頂-14069.2737-23180.9692-27449.74860.428526911.51830.021739J[40]底1868.247910263.433711721.4429-0.835311491.62420.009339J[40]頂-88.4357-5591.3959-6392.92110.23386267.57710.005147J[48]底7318.176117281.470120460.6407-0.852520059.47530.016247J[48]頂-668.4703524.8292-6.45060.45246.32410.000054J[55]底187.91328138.69819079.3134-0.77959299.61350.007554J[55]頂-1679.3990-7352.3484-8184.52760.34338024.05610.006561J[62]底-413.3815-10950.9543533.6606-0.8248523.19660.000461J[62]頂-16642.7778-26083.4350-31001.76120.429230397.80520.024670J[71]底6846.587114361.901617100.0753-0.835516764.79950.013670J[71]頂-18.10581241.1026-3718.93510.44953646.01910.003078J[79]底15666.927324041.860829504.9904-0.842628926.49520.023478J[79]頂-72.419212168.6544-422.90840.4496414.61660.000384J[85]底12869.139918884.486023339.9683-0.830322882.32180.018584J[85]頂-21.837511079.7264139.73390.27530.00000.000092I[92]底-18.3910-24.8214-24.8214-0.53950.00000.000092I[92]頂-1666.4330-311.0809-1911.29190.20211877.73720.00151,9,16和23單元在支座的左側(cè)，1/4L，1/2L，3/4L;32,39,47,54,61單元在支座的中間，1/4L，1/2L，3/4L;70,78,84,92位，右跨度1/4L，1/2L，3/4L和支撐。預應力鋼筋的最大面積出現(xiàn)在61單元，所需面積為0.0246m2，預應力鋼筋的最大面積出現(xiàn)在78單元，所需面積為0.0234m2。根據(jù)預應力筋的估算形式，所需鋼筋的最大面積為0.0246m2。因此，在橋梁設計中共有20根預應力鋼筋，分為上板預應力鋼筋、下板預應力鋼筋和腹板預應力鋼筋三組。該橋采用高強度低松弛鋼絞線strand1860，直徑為11.2mm，標準強度為1860Mpa，錨桿下的張拉控制應力為1395Mpa。該橋由20根預應力鋼絞線組成，按形狀分為T1、T2、T3、B1、B2、B3、F1、F2和F3。每股由19股組成，每股12股，剩下的兩捆，每捆由12股組成。鋼梁波紋管為90毫米，如圖1.1所示，用于總結(jié)預應力鋼結(jié)構。編號下料鋼絞線規(guī)格（mm）單根長（mm）束數(shù)總長（m）總重（kg）T112-φ11.2387762698.0768.5T212-φ11.2478352861.0948.0T312-φ11.2387762698.0768.5F119-φ11.27946123019.53324.4F219-φ11.28354323174.63491.3F319-φ11.28761123329.33661.5B112-φ11.28585244120.94537.1B212-φ11.26638421194.41311.0B312-φ11.26638421194.41311.0圖1.1預應力鋼束工程數(shù)量匯總1.2預應力鋼束的布置1.2.1預應力鋼束的布置原則預應力的重心線要在束界范圍內(nèi)；錨具類型要與預應力鋼束適合；預應力鋼梁布置既要滿足結(jié)構受力要求，又要滿足次內(nèi)力要求；預應力鋼絞線的布置應考慮材料的經(jīng)濟因素和施工技術條件；。布置預應力鋼束時要盡量對稱；預應力鋼梁分層布置時，應在靠近橫截面頂板或底板的一側(cè)布置較長的梁，而較短的梁應在遠離橫截面頂板或底板的一側(cè)布置預應力鋼索分層布置時，應先將下部預應力鋼索錨固，然后再將上部預應力鋼索錨固。1.2.2預應力鋼束的布置該橋的預應力鋼束由直線和圓弧組成，半徑為8米。在橋的左側(cè)，安裝頂板預應力筋T1和底板預應力筋B2。在橋梁右側(cè)，頂板預應力筋T3與底板預應力筋B3對稱布置。中跨設置頂板預應力鋼梁T2、腹部預應力鋼梁F1、F2、F3和底板預應力鋼梁B1。橫梁在橫截面上對稱布置。例如，圖1.2顯示了預應力鋼絞線的縱向布置，圖1.3顯示了預應力鋼絞線的橫截面，表1.2顯示了預應力鋼絞線的結(jié)構。圖1.2預應力鋼束縱向布置圖圖1.3預應力鋼束橫截面圖表1.2預應力鋼束配置表單元截面上緣（根）截面下緣（根）1229410162122341232104394124721254412611067041078210844892221,9,16和23單元在支座的左側(cè)，1/4L，1/2L，3/4L;32,39,47,54,61單元在支座的中間，1/4L，1/2L，3/4L;70,78,84,92位，右跨度1/4L，1/2L，3/4L和支撐。1.3模擬預應力鋼束預應力鋼梁共20根，分為上預應力鋼梁、下預應力鋼梁和腹板預應力鋼梁。首先定義預應力鋼束的特征值，然后利用該特征值選取預應力鋼束的相應特征值，引入水平和垂直彎曲圖形生成mct文件，通過操作文件將鋼束插入梁體，調(diào)整預應力鋼束的插入點和分布單元，使20根鋼梁依次插入箱梁的合適位置。圖1.4顯示了鋼梁的特點，圖1.5顯示了G鋼束的排列，圖1.6顯示了鋼梁的形狀。圖1.4鋼束特性值圖1.5布置鋼束圖1.6鋼束的形狀1.4鋼束的預應力損失在預應力混凝土橋的設計中，所需的預應力通常取決于橋梁所承受的荷載大小。但往往是由于預應力鋼筋與管壁之間的摩擦、錨固變形、收縮和節(jié)點壓縮、預應力鋼筋與支座之間的溫差、混凝土的彈性壓縮、預應力鋼筋的應力松弛、混凝土的收縮和徐變使實際預應力小于張拉控制應力，二者之間的差別就是預應力損失。即張拉控制應力，即預應力損失。在設計這類構件時，必須考慮預應力損失，使預應力尺寸滿足荷載尺寸要求，因此必須對鋼梁的預應力損失進行計算。Midas可以在結(jié)果柱的結(jié)果表中選擇預應力損失，然后我們可以看到鋼束在某一施工階段的預應力損失，表1.3。表1.3T1的預應力損失單元應力(考慮瞬時損失)彈性變形損失:B(kN/m^2)比值(A+B)/A徐變/收縮損失(kN/m^2)松弛損失(kN/m^2)應力(考慮所有損失)/應力(考慮瞬時損失)端部有效鋼束數(shù):A(kN/m^2)鋼束組T1階段橋面鋪裝11173210.9423461.55841.0004-4397.3487-21517.62170.9783221173210.9423467.10041.0004-4397.6447-21517.62170.9783231180571.8432290.23061.0002-6174.2765-22308.45550.9761241189718.2571-241.18220.9998-7777.5900-23302.51430.9737251198804.2919-831.92630.9993-15169.3192-24302.51310.9664261213587.4760-2038.42140.9983-16616.6066-25956.16390.9633271232383.2954-2722.97120.9978-19644.2164-28106.30070.9591281241157.3868-3508.87120.9972-18296.7039-29128.26390.9590291249873.7598-3912.20150.9969-21693.2444-30151.00960.95542101260688.6433-4563.27610.9964-21011.7473-31444.89070.95482111271414.6661-4927.08330.9961-21721.9247-32741.61060.95332121279931.9932-5122.71930.9960-22309.6081-33783.68010.95222131277788.3686-5212.99190.9959-23059.1259-33520.38280.95172141269382.7198-5211.01330.9959-23559.4265-32494.62570.95182151261032.3670-5122.01930.9959-23961.4445-31486.17590.95202161250671.6363-4869.58960.9961-24237.1652-30249.56850.95262171244496.1065-4648.90000.9963-24260.4291-29520.19360.95312181236309.4695-4272.46720.9966-24120.4279-28562.16580.95402191228176.6752-3801.07360.9969-23886.7314-27620.45530.95502201220097.3947-3231.76270.9974-23442.8473-26694.82630.95632211212071.2548-2571.49280.9979-22901.2674-25781.04080.95772221206847.3172-1819.82020.9985-22151.6185-25198.11660.95932231214838.8602-953.45520.9992-21491.5945-26097.65830.96012241222883.3268211.22311.0002-23942.4972-27012.89260.95852251230981.05501438.96341.0012-25491.0374-27944.05160.95782261239132.41692840.69451.0023-27923.6597-28891.37390.95652271247337.73874210.63581.0034-28864.2477-29851.09600.95632281251047.84154790.16761.0038-27566.0537-30294.18700.95762291259332.08115916.13731.0047-26284.5528-31282.12660.95902301243727.67188276.29251.0066-21874.3333-29429.83860.96542311243727.67188241.50481.0066-18149.2437-29429.83860.96842321236967.74219306.74511.0075-16698.7918-28638.82510.97092331230172.02328431.01711.0068-24147.3061-27850.57590.96462331221626.76656784.06081.0055-24367.2648-26869.28770.96362341221626.76656751.84141.0055-24310.5447-26869.28770.96372351213024.93455231.15121.0043-23119.9670-25892.