半平行钢丝索由于其钢丝的螺旋外形和本身构造的特殊性，难以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．文中基于 Love 曲杆理论，考虑钢丝弯矩、扭矩和泊松效应的影响，推导了静力拉伸荷载作用下的多层半平行钢丝索的非线性方程; 重点讨论了螺旋角对半平行钢丝索轴力、轴向刚度和钢丝层间拉力分布等的影响．数值计算表明: 随着螺旋角的增大，轴力、轴向刚度随之增大，而扭矩则先增大后减小，钢丝层间拉力分布逐渐趋于均匀．

It is difficult to employ the parallel model or the steel strand model based on the assumption of parallel wire to analyze the mechanical properties of the semi- parallel cable due to its helical characteristics and special structure.In this paper,a nonlinear equation of multilayered semi- parallel cable under the static tensile load is de-rived based on the theory of Love's curved bar and by considering the effects of the bending moment,the torque and the Poisson effect.Moreover,the effects of the helical angle on the axial force,the torsion,the axial stiffness and the distribution of the tensions between wire layers are discussed in detail.Numerical results show that,with the in-crease of the helical angle,both the axial force and the axial stiffness increase,the torque first increases and then decreases,and the distribution of the tensions between wire layers tends to be uniform.