中文摘要：

为更清楚地认识平面缆索结构及桥塔的纵向力学行为，基于主缆线形计算的传统抛物线理论，推导单跨缆索结构纵向刚度的解析公式；结合算例与有限元及既有文献结果进行对比；基于梁的平衡微分方程和能量原理，推导索塔结构的纵向刚度计算公式，并与有限元计算结果进行对比；由力学分析导出连跨缆索结构在考虑和不考虑支点刚度时的纵向刚度解析公式；讨论单跨缆索结构纵向刚度的影响因素；利用有限元给出单跨和双跨加载时的连跨缆索结构纵向刚度变化曲线。研究表明，导出的解析公式具有良好的精度，能够满足工程需要。

英文摘要：

In order to understand the longitudinal mechanical behavior of plane cable structures and pylons bet-ter,analytical formula based on the traditional theory of parabolic shaped main cable was derived for the longitu-dinal stiffness of single span cable structures,comparison was taken between analytical formula,the existing lit-erature and finite element method by examples.Analytical formula based on the equilibrium differential equation of beam and the energy principle for the longitudinal stiffness of pylons was also derived.Comparison was taken between analytical formula and finite element method by examples.Analytical formulas were derived for the lon-gitudinal stiffness of multi -span cable structures.Influencing factors of the longitudinal stiffness for single span cable structures were discussed.Changable curves of the longitudinal stiffness for multi -span cable structures were given both in the single -span and the double -span concentrated loading situation by finite element meth-od.Studies have shown that the analytical formulas can meet the needs of engineering with good precision.