钢绞线张拉过程中伸长值超差原因分析

Elongation oversize cause analysis during tension of steel strand

针对Φ15.24 mm 1 860 MPa钢绞线张拉过程中实际伸长值与设计伸长值偏差超过±6%,钢绞线的性能不能满足要求的问题,对该段钢绞线进行取样检验,并重新计算理论伸长值。结果显示,将钢绞线的横截面积由原来的公称面积140 mm2改为实际面积141 mm2,弹性模量由2.01×105MPa改为产品质保书上的检验数据1.96×105MPa,钢绞线与孔道的摩擦因数取0.17,孔道每米局部偏差对摩擦的影响因数取0.002,张拉端至计算截面曲线孔道部分切线的夹角之和取0.087 7 rad后,重新计算的理论伸长值与实际伸长值偏差在±3.5%以内。

The steel strand was sample selected and tested, the theoretic elongation was calculated again according to the problem that the deviation is over ± 6% of actual elongation and designing elongation in diameter 15.24 mm 1 860 MPa steel strand tension process, properties of steel strand can＇t reach requirements. Results show： the deviation of calculating theoretic elongation and actual elongation is within ± 3.5% after the cross-sectional area of steel strand is changed from former nominal area 140 mm2 to actual area 141 mm2 , elastic modulus is changed from 2.01× 10^5 MPa to test datum 1.96 × 10^5 MPa of product inspection certificate, the friction factor of steel strand and pore canal is 0.17, the influence of pore ca- nal partial deviation each meter on friction is 0. 002, the included angle summation of tension end and calculating section curve pore canal tangent is 0. 087 7 rad.