T梁張拉伸長(zhǎng)量計(jì)算值(示例)

30m、40mT梁張拉伸長(zhǎng)量計(jì)算值(按μ=0.17,k=0.0015計(jì)算）彈性模量Ep=1.95×105MPa根據(jù)后張預(yù)應(yīng)力筋理論伸長(zhǎng)值及預(yù)應(yīng)力筋平均張拉力的計(jì)算式：P（1-×e-(kx-EP（1-×e-(kx-Ep)）AP×EPPP×LKx+μθΔL= PP=Kx+μθ式中:△L—預(yù)應(yīng)力筋理論伸長(zhǎng)值：cm；P—預(yù)應(yīng)力筋的平均張拉力，N；x—從張拉端至計(jì)算截面孔道長(zhǎng)度，cm；Ap—預(yù)應(yīng)力筋截面面積，mm2；Ep—預(yù)應(yīng)力筋的彈性模量，Mpa；p—預(yù)應(yīng)力筋張拉端的張拉力，N；θ—從張拉端至計(jì)算截面曲線孔道部分切線的夾角之和，rad；k—孔道每米局部偏差對(duì)摩擦的影響系數(shù)，0.0015；μ—預(yù)應(yīng)力筋與孔道避的摩擦系數(shù)，0.17；中主梁(以30m中梁為例)1.N1（1*6）預(yù)應(yīng)力筋截面面積Ap=140*6=840錨下控制應(yīng)力σcon=0.72Ryb=0.72*1860=1339.20MPa起始端頭張拉力p1=σcon*Ap=1339.2*840=1124.928KN由圖紙說(shuō)明：θ=4.46°*3.14/180°=0.078radL=31.6806-2*1=2L彎=5*2=10L直=(29.6806-10)/2=19.6806/2=9.8403μ=0.17,K=0.0015,由張拉力的計(jì)算公式:[1-e-(kx+μθ)]1-e-(0.0015*5+0.23*0.078)P=P×=1124.928*kx+μθ0.0015*5+0.23*0.078=1110.739KNp2=2P-P1=1110.739*2-1124.928=1096.55KNＰ×Ｌ△L==1110.739*103*5*100/(840*1.95*105)Ａy×Eg=3.△L直=P2×L/Ap×E=1096.55*9.8403*105/840/1.95*105=6L=(3.39+6.59)*2=19.千斤頂工作長(zhǎng)度的伸長(zhǎng)量計(jì)算:ΔL=PL/ApEy=σk*Ap*L/ApEy=σk*L/Ey=1124.928*1/840*1.95*105=0.68邊跨邊梁(以40m邊梁為例)1.N1（1*8）預(yù)應(yīng)力筋截面面積Ap=139×8=1112mm2錨下控制應(yīng)力σcon=0.68Ryb=0.68*1860=1264.8MPa起始端頭張拉力p1=σcon*Ap=1264.8*1120=1416.58KN由圖紙說(shuō)明：θ=2.23°*3.14/180°=0.039radL=36.6654-2*1=34.6654L彎=4.5*2=9L直=(34.6654-9)/2=25.6654/2=12.8327μ=0.23,R=0.0015,由張拉力的計(jì)算公式:[1-e-(kx+μθ)]1-e-(0.0015*4.5+0.23*0.039)P=P×=1416.58*kx+μθ0.0015*4.5+0.23*0.039=1405.5KNp2=2P-P1=1405.5*2-1416.58=1394.42KNＰ×Ｌ△L==1405.5*103*4.5*100/(1120*1.95*105)Ａy×Eg=2.90cm△L直=P2×L/Ap×E=1394.42*12.8327*105/1120/1.95*105=8.