中文摘要：

将空间缆索悬索桥塔顶鞍座归纳为水平母线鞍座和倾斜母线鞍座2类,以鞍座理论顶点为顺延悬链线交点的定义为基础,讨论了倾斜母线鞍座设计位置的确定问题。从力学关系和几何特征出发,导出了确定倾斜母线索鞍位置的11元非线性方程组,采用牛顿-拉斐森迭代法进行求解,给出了迭代格式与步骤,推导了雅可比矩阵,讨论了迭代初值的确定方法,明确了约束条件,确保了索鞍设计位置迭代快速收敛于真实值。在此基础上,基于几何关系和虎克定律,给出了索鞍顶部主缆无应力长度的计算方法。最后给出了确定索鞍设计位置和索鞍顶部主缆无应力长度的算例。结果表明：该算法简明,能快速、高精度收敛于真实解。

英文摘要：

Saddle of suspension bridge with spatial cables was divided into the level busbar saddle and lean busbar saddle. Based on the saddle＇s theoretical apex which was defined as extensive catenary crossing point, the method of lean busbar saddle＇s position was explored. The eleven nonlinear equations were derived from mechanical relationship and geometrical character, which were solved by the Newton-Raphson iterating method. The step and iterating method were introduced. The Jacobian matrix was deduced; the method for determing iterative initial value was discussed. The constraint condition, which quickly ensures the iteration to converge at the true solution was improved. According to the geometrical relationship and hook＇s law, calculation method on the unstressed length of cable apex on the saddle was also deduced. At last, the sample for determing saddle＇s position and the unstressed length of cable on the saddle was given. Results show that the method is feasible and can converge at the true solution quickly and preferably.