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1、预应力钢筋的理论伸长值计算已知：张拉控制应力k=1357.8Mpa，Ay=142.6mm2，Ey= Mpa，=0.175，k=0.0008；1号钢束：实测摩阻力为115 Mpa，理论摩阻力为123.1 Mpa，张拉力Pk=1357.8142.612=2323.5KN将半个曲线预应力筋分成八段，各段参数表为：线段L(m)(rad)e-(kL+)终点力(KN)AB6.20.0690.98312284.2BC3.3200.99732278CD8.50.07280.98062233.8DE3.4500.99722227.5EF8.10.10080.97622174.5FG4.7900.99622166
2、.2GH8.10.10080.97622114.6HI200.99842112.9将表中数据代入公式：l=PL/AyEy，P=P(1+ e-(kL+)/2，得P1=2323.5(1+0.9831)/2=2303.87KNl1=2303.871036.2/(1711.2)=0.0422mP2=2284.2(1+0.9973)/2=2281.12KNl2=2281.121033.32/(1711.2)=0.02239mP3=2278(1+0.9806)/2=2255.9KNl3=2255.91038.5/(1711.2)=0.05669mP4=2233.8(1+0.9972)/2=2230.67K
3、Nl4=2230.671033.45/(1711.2)=0.02275mP5=2227.5(1+0.9762)/2=2200.99KNl5=2200.991038.1/(1711.2)=0.0527mP6=2174.5(1+0.9962)/2=2170.37KNl6=2170.371034.79/(1711.2)=0.0307mP7=2166.2(1+0.9762)/2=2140.42KNl7=2140.421038.1/(1711.2)=0.0513mP8=2114.6(1+0.9984)/2=2112.91KNl8=2112.911032/(1711.2)=0.01249m求得l=20.2
4、9121=0.58242m=58.242cm在梁端处N1钢束伸长量为：29.121cm2号钢束：实测摩阻力为275 Mpa，理论摩阻力为134.9 Mpa，张拉力Pk=(1357.8+275-134.9)142.612=2563.2KN将半个曲线预应力筋分成六段，各段参数表为：线段L(m)(rad)e-(kL+)终点力(KN)AB40.0920.98092514.2BC7.4500.99412499.4CD80.1010.97622439.9DE80.1010.97622381.9EF900.99282364.7FG80.1010.97622308.4将表中数据代入公式：l=PL/AyEy，P
5、=P(1+ e-(kL+)/2，得P1=2563.2(1+0.9809)/2=2538.7KNl1=2538.71034/(1711.2)=0.0300mP2=2514.2(1+0.9941)/2=2506.8KNl2=2506.81037.45/(1711.2)=0.0552mP3=2499.4(1+0.9762)/2=2469.7KNl3=2469.71038/(1711.2)=0.0584mP4=2439.9(1+0.9762)/2=2410.9KNl4=2410.71038/(1711.2)=0.0570mP5=2381.9(1+0.9928)/2=2373.3KNl5=2373.31
6、039/(1711.2)=0.0632mP6=2364.7(1+0.9762)/2=2336.6KNl6=2336.61038/(1711.2)=0.0553m分段求得l=20.3191=0.6382m=63.82cm在梁端处N2钢束伸长量为：31.91cm横梁计算已知：张拉控制应力k=1120Mpa，Ay=142.6mm2，Ey= Mpa，=0.175，k=0.0008；线段L(m)(rad)1+e-(kL+)2终点力(KN)AB6.40.5130.95471347.3L=1347.3106.4/1260=0.0346m横梁张拉压力表读数顶号压力表号初应力100%应力103%应力141.12
7、KN读数MPa1411.2KN读数MPa1453.5 KN读数MPa1141.122.1691411.241.1351453.542.4322141.124.7841411.242.9121453.544.1811141.120.7931411.216.4791453.517.0012141.120.5971411.216.2191453.516.739主梁1号束张拉压力表读数395.0 KN（0.17%） 、2323.5KN（100%）、2393.2 KN（103%） 、2439.7 KN105%顶号压力表号应力备注0.17%100%103% 105%读数MPa读数MPa读数MPa读数MPa19.958顶和表号要对应212.40513.92927.74628.60629.18123.47227.44028.29828.870主梁2号束张拉压力表读数435.7 KN（0.17%）、 2563.2KN（100%）、2640.1 KN（103%）、 2691.4 KN（105%）顶号压力表号应力备注0.17%100%103% 105%读数MPa读数MPa读数MPa读数MPa111.206顶和表号要对应213.62714.43130.70631.65632.28824.22030.38931.33531.716
