预应力钢束引伸量计算

计算钢束编号：1预应力钢束采用一束13φ15.20钢铰线；预应力筋张拉控制应力σcon=1357.8Mpa预应力筋截面面积Ap=1820mm2超张拉系数b=1预应力筋弹性模量Ep=195000Mpa预应力筋的锚下张拉力：Ncon=σcon×Ap×b/1000=2471.196kN预应力筋伸长量分段计算，考虑预应力钢筋与管道壁间摩擦引起的预应力损失后的张拉力N=Ncon[1-e-（μθ+kx）]预应力筋理论伸长值Δl=Pp×l/（Ap×Ep）预应力筋平均张拉力Pp=Pp×[1-e-（μθ+kx）]/（μθ+kx）根据以上公式分段计算，结果如下表：线段张拉控制力（kN）Ap(mm2)Ep(Mpa)l(m)θ(rad)μkμθ+kx2471.19618201950006.95400.170.00150.010432445.54518201950000.7090.07155850.170.00150.013232413.411182019500019.862300.170.00150.029792342.57718201950001.0040.10122910.170.00150.018712299.14618201950001.96200.170.00150.00294由表中数据分段求得Δl=205.5mm预应力钢筋理论伸长值计算e-（μθ+kx）终点力（kN）Δl(mm)0.989622445.54548.20.986862413.4114.90.970652342.577133.10.981462299.1466.60.997062292.38712.7预应力钢筋理论伸长值计算