无应力状态法在钢绞线斜拉索施工中的应用

针对平行钢绞线斜拉索施工过程中的索力控制问题,提出采用无应力状态法理论确定单根斜拉索中每根钢绞线挂设初张力的方法.基于无应力状态法理论与悬链线索元理论建立斜拉索无应力索长与张拉力的关系式,以各次钢绞线挂设完成为平衡状态进行力学分析,建立求解单根钢绞线张拉力的非线性方程组,采用MATLAB编程,运用最速下降法迭代得到非线性方程组的数值解.以武汉某大桥正桥为例,对其中跨22号斜拉索中单根钢绞线张拉力进行求解,结果表明所推导的方法是准确和有效的.

Application of Unstressed State Method to Construction of Steel Strand Stay Cable

In view of the problem of cable force control in construction of the parallel steel strand stay cable,a method using the unstressed state method theory for determination of the initial tensioning force of installation of each steel strand in a single stay cable was proposed.In accordance with the unstressed state method theory and the catenary cable element theory,the relationship expression for the unstressed cable length and tensioning force of the stay cable was established and the mechanical analysis of the balance state after installation of the steel strand each time was made.The nonlinearity equation set for solving the tensioning force of a single strand was established as well and with the program MATLAB and iteration of the steepest descent method,the numerical solution to the nonlinearity equation set was obtained.By way of example of the main bridge of a bridge in Wuhan,the tensioning force of the single steel strand of Stay Cable No.22 at the central span of the bridge was solved and the results of the solution prove that the method proposed herewith is correct and effective.