双套拱塔斜拉桥索力张拉优化及控制

Optimization and Control of Tensioning of Cables of Cable-Stayed Bridge with Double-Set Arch Pylons

为研究双套拱塔斜拉桥施工控制技术,尤其是塔间索及斜拉索的张拉方案合理性及张拉控制方法,以小凌河大桥为背景,采用MIDAS Civil有限元软件建立该桥空间计算模型,进行施工过程的模拟计算,根据计算结果对拉索安装和张拉方案进行了优化。优化后,赋予塔间索初张拉无应力长度,二次调索时调整到成桥状态的无应力长度;斜拉索自内而外安装并张拉,索力小于250kN的斜拉索,调整其初张拉无应力长度使索力满足测量要求,其他斜拉索直接张拉到设计的无应力长度。监控结果表明,采用优化后的索力张拉方法对该类桥梁进行施工控制,整个施工过程中结构安全、受力明确,得到的成桥索力误差小。

To study the construction control techniques for the cable-stayed bridge with double-set arch pylons, particularly the rationality of the schemes and control methods for tensioning of the cables between the pylons and the stay cables of the bridge, the Xiaoling River Bridge of such type was cited as an example. The spatial calculation model for the bridge was established by the finite element software MIDAS Civil, the simulation calculation of the construction process was made and the installation and tensioning of the cables were accordingly optimized in terms of the results of the calculation. After the optimization, the unstressed length was given to the ini- tial tensioning of the cables between the pylons, the unstressed length was then adjusted to the unstressed length of the completed bridge status when the second-time cable force adjustment was carried out. The stay cables were installed and tensioned from the inner side to the outer side and for the stay cables with cable forces less than 250 kN, the unstressed length of the initial tensio- ning of these cables was adjusted to make the cable forces meet the measurement requirements while for the rest of the stay cables, they were directly tensioned to the designed unstressed length. The results of the monitoring and control of the construction process show that by means of the construction control of the bridge of such type, using the optimized cable tensioning method, the structure of the bridge in the whole construction process is safe, the force conditions are clear and the errors of the obtained cable forces of the completed bridge are little.