张紧的平行钢丝索股在端部转动条件下的弯曲特性试验研究

Experimental Study on Bending Characters of Tensioned Parallel Wire Strands with Rotational End

桥梁缆索结构的弯曲应力对钢丝的疲劳寿命和应力腐蚀有明显影响,但传统的梁弯曲计算方法不能很好反应缆索结构的弯曲特性。通过模型试验对受张拉的平行钢丝索股在端部转动时的弯曲特性研究,试验结果表明:平行钢丝索股的初始张力、端部转角大小对弯曲应力影响明显,而索股有效长度影响不明显。索股钢丝之间在达到最大摩擦力前不发生滑移,抗弯刚度保持不变;随着弯曲曲率增加,沿索股径向和法向扩散出现分层滑移现象,索股截面的整体性降低,抗弯刚度逐渐减小;当索股钢丝全部产生滑移后,端部的抗弯刚度不再变化。

The bending stress of bridge cable structure has a distinct effect on fatigue life and stress corro-sion, but traditional calculation method of bending beam cannot well express the bending characters of cable structure. Through the experimental study on bending characters of tensioned parallel wire strands with a rotational end, the results indicate: initial tension and end rotation angle of strand obviously impact on bending stress, but effective strand length influences feebly. The bending stiffness will not change until friction between parallel wires reaches maximum. With layering slippage diffuses along radial and axial directions when bending curvature increases, strand section integrality and bending stiffness decrease gradually. Finally the bending stiffness of strand end maintains invariable after all parallel wires slip.