桥梁半平行钢丝索对称断丝的力学特性分析

Mechanical Properties Analysis of Semi Parallel Wire Cables for Bridges with Symmetric Wires Break

摘要:

桥梁用半平行钢丝索由于外层钢丝的螺旋外形和本身构造的特殊性，不能直接应用基于平行钢丝假定的并联模型或钢绞线模型进行力学分析。基于Love曲杆理论，考虑泊松效应和钢丝间接触变形的影响，及钢丝间的接触力和摩擦力，对多层半平行钢丝索的对称断丝模型进行了修正，通过数值计算讨论了拉索截面钢丝拉力分布规律、钢丝拉力增长系数和拉索轴向刚度及其影响因素。计算表明，考虑接触变形后，截面内钢丝拉力分布不均匀，拉索轴向刚度较单根钢丝有较大幅度的下降。

Abstract:

Strands model or parallel model based on the assumption of parallel wire is helpless to semi parallel wire cable for its helical characteristics and complex structure. Based on the theory of Love’s curved bar, considering effects of the Poisson’s ratio and contact deflection between wires, introducing inter-wire contact force and friction, the mechanical model for multilayered semi parallel wire cables with symmetric wire breaks were updated. With some emphasis, axial force distribution of wires, magnification factors of axial force and axial stiffness of cable are discussed by numerical calculation. Numerical examples show that contact deformations aggravate nonuniform distribution of wires’ axial force and that the axial stiffness of cable falls much after wires break.