關(guān)于簡(jiǎn)支梁橋的鋼束損失估算計(jì)算過(guò)程案例目錄TOC\o"1-3"\h\u19646關(guān)于簡(jiǎn)支梁橋的鋼束損失估算計(jì)算過(guò)程案例 117611.1鋼束應(yīng)力損失 142741.2預(yù)應(yīng)力鋼筋與管道間摩擦引起的預(yù)應(yīng)力損失 1323221.3錨具變形、鋼絲回縮引起的應(yīng)力損失 2147101.4預(yù)應(yīng)力鋼筋分批張拉時(shí)混凝土彈性壓縮引起的應(yīng)力損失 3198111.5鋼筋松弛引起的預(yù)應(yīng)力損失 334421.6混凝土收縮、徐變引起的應(yīng)力損失 41.1鋼束應(yīng)力損失預(yù)應(yīng)力鋼筋張拉（錨下）控制應(yīng)力：按《公路橋規(guī)》采用1.2預(yù)應(yīng)力鋼筋與管道間摩擦引起的預(yù)應(yīng)力損失對(duì)跨中截面：,,,,,,將結(jié)果匯總于下表：表1.1支點(diǎn)截面摩擦應(yīng)力損失計(jì)算表鋼束編號(hào)θμθx(m)kx（×10-4）β=1-e-(μθ+kx)（×10-4）σcon(MPa)σl1(MPa)(°)(rad)N10000.1352.0252.0213950.282N20000.1852.7752.7713950.386N30000.2403.6003.6013950.502表1.2四分點(diǎn)截面摩擦應(yīng)力損失計(jì)算表鋼束編號(hào)θμθx(m)kx（×10-4）β=1-e-(μθ+kx)σcon(MPa)σl1(MPa)(°)(rad)N10001.1350.9209.16×10-3139564.728N29.580.16720.04011.1850.9280.0482139589.699N370.12220.02931.2400.9360.0379139589.838表1.3跨中截面摩擦應(yīng)力損失計(jì)算表鋼束編號(hào)θμθx(m)kx（×10-4）β=1-e-(μθ+kx)σcon(MPa)σl1(MPa)(°)(rad)N170.12220.029312.1350.01820.0464139564.728N211.5080.20090.048212.1850.01830.0643139589.699N311.5080.20090.048212.2400.01840.0644139589.838將其他位置的控制截面處的平均摩擦應(yīng)力損失匯總于下表1.4：表1.4各設(shè)計(jì)控制截面摩擦應(yīng)力損失平均值截面跨中四分點(diǎn)支點(diǎn)平均值81.4244.300.391.3錨具變形、鋼絲回縮引起的應(yīng)力損失，，反摩擦影響長(zhǎng)度計(jì)算結(jié)果見(jiàn)表1.5。表1.5反摩擦影響長(zhǎng)度計(jì)算表鋼束編號(hào)σ0=σcon(MPa)σl1(MPa)σl=σ0-σl1(MPa)l(mm)Δσd=(σ0-σl1)/l(MPa/mm)lf(mm)N1139564.7281330.272121355.33412093N2139589.6991305.301121857.36110294N3139589.8381305.162122407.34010309三束鋼絞線均滿足lf≤l，預(yù)應(yīng)力損失為：式中，若，表示該截面不受反摩擦影響，各控制截面計(jì)算如下表1.6。表1.6錨具變形引起的預(yù)加應(yīng)力損失計(jì)算表截面鋼束編號(hào)x(mm)lf(mm)Δσσl2各控制截面平均值跨中截面N1121351213512135x>lf0N2121851218512185N3122401224012240四分點(diǎn)截面N16135121351213563.5661.42N26185121851218560.49N36240122401224060.22支點(diǎn)截面N11351213512135127.57141.80N21851218512185148.81N32401224012240149.021.4預(yù)應(yīng)力鋼筋分批張拉時(shí)混凝土彈性壓縮引起的應(yīng)力損失對(duì)于本設(shè)計(jì)取四分點(diǎn)截面由混凝土壓縮產(chǎn)生的應(yīng)力損失作為全梁各截面的平均值，即：得到結(jié)果為：其中：,,，，1.5鋼筋松弛引起的預(yù)應(yīng)力損失由公式可得：式中：，，1.6混凝土收縮、徐變引起的應(yīng)力損失可直接公式直接計(jì)算結(jié)果，式中系數(shù)取值：，，故可得跨中截面：四分點(diǎn)截面：因此，跨中截面與四分點(diǎn)截面平均值為：。計(jì)算，（未計(jì)構(gòu)造影響）。對(duì)，取跨中截面與四分點(diǎn)截面平均值來(lái)計(jì)算，則：跨中截面四分點(diǎn)截面故其平均值為：。而其換算截面的面積平均值，換算截面的慣性矩平均值，代入上述公式計(jì)算：最后結(jié)果得到：各截面鋼束預(yù)應(yīng)力損失品平均值和有效預(yù)應(yīng)力匯總見(jiàn)表1.7。表1.7各截面鋼束預(yù)應(yīng)力損失品平均值和有效預(yù)應(yīng)力匯總表計(jì)算截面預(yù)加應(yīng)力階段σlⅠ=σl1+σl2+σl4(MPa)使用階段σlⅡ=σl5-σl6(MPa)鋼束有效預(yù)應(yīng)力(MPa)σl1σl2σl4σlⅠσl5σl6σlⅡ預(yù)加力階段σpⅡ=σcon-σlⅠ使用階段σpⅡ=σcon-σlⅠ-σlⅡ跨中截面81.42031.3117.7230.55101.1131.651277.281140.63四分點(diǎn)