一种斜拉桥目标状态索力快速精准确定的方法

为了精准高效地确定斜拉桥目标状态索力,提出一种新型快速精准调索方法。该方法实施步骤为:计入结构的几何非线性效应,对斜拉索施加一定初张力确定计算初态;在计算初态基础上设定斜拉索的索力增量作为主调向量,通过逐次轮换主调向量进行有限元计算,相比计算初态确定关心截面内力或位移的增量效应矩阵及边界矩阵等参量;利用数值优化理论,建立约束条件及目标优化函数求解出满足要求的最优索力。以主跨518 m的荆岳铁路公安长江特大斜拉桥为工程实例,对该桥成桥状态、施工过程子目标状态的索力进行优化并对施工监控误差进行修正。结果表明:优化后的结构状态均满足工程要求,该调索方法具有快速、高效、精准等优点,可推广至斜拉桥、拱桥等成桥状态和施工过程控制子目标状态的索力确定,并为施工监控索力调整等提供了一种新的解决途径。

A Method to Rapidly and Accurately Determine Target Cable Forces for Cable-Stayed Bridge

To accurately and efficiently determine the target-state cable forces of a cable-stayed bridge,a method for rapid and accurate cable forces tuning is proposed.In the specific operation,the geometrical nonlinearity effect of the structure is counted and certain initial tensioning forces are applied to stay cables,to figure out the initial state of calculation.Then,on the basis of the calculation initial state,the cable force increments are set as the main tuning vectors,which are converted in sequence to conduct finite element calculation,and referring to the calculation initial state,the parameters,like the effect matrix relevant to cross-section internal forces and displacements as well as boundary matrix,are determined.The constraints and target optimization function are fit using the numerical optimization theory,to gain the optimum cable forces that meet the requirements.The Gong′an Changjiang River Bridge on Jingzhou-Yueyang Railway with a main span of 518 m was taken as the example project,to which the completed bridge state and cable forces under subsidiary target condition in the construction process were optimized and errors in construction monitoring and control were modified.The results show that the structural condition after optimization can meet the engineering requirements,and the method allows rapid,efficient and accurate tuning of cable forces,which can be used to determine the cable forces of the cable-stayed bridge,arch bridge and suspension bridge in the completed bridge state and under the subsidiary control target state in the construction process.The method offers a new way to address cable forces tuning issue in construction monitoring and control.