超大跨斜拉桥横桥向恒载非对称力学行为

Mechanical Characteristics of Super-Long-Span Cable-Stayed Bridge with Transverse Asymmetrical Load

为研究横桥向非对称恒载对大跨度斜拉桥受力行为的影响,以常泰长江大桥为工程背景,对横桥向非对称恒载桥梁结构的力学行为进行分析,并提出了合理的控制措施以实现理想的成桥状态.提出了一种索力快速优化的方法,采用上下游索力不对称和降低铁路二期恒载的措施解决横桥向不对称恒载引起的主梁扭转、主塔偏位问题,实现了合理的成桥状态.结果表明:通过上下游索力不对称可以有效地控制主梁扭转,斜拉索顺桥向不平衡分力和横桥向不平衡分力产生的横桥向弯曲变形大小基本一致,方向相反,有利于降低主梁横桥向弯曲变形;通过减小横桥向不对称恒载的差值可以有效地控制主塔横桥向偏位.

In order to study the influence of transverse asymmetrical load on the mechanical characteristics of long-span cable-stayed bridges,this paper takes the Changtai Yangtze River Bridge as the engineering background and analyzes the mechanical characteristics of the bridge with a transverse asymmetrical load.In addition,reasonable control measures are put forward to realize the ideal state of the final bridge.Firstly,a fast optimization method of the cable force is proposed for the cable-stayed bridge with a transverse asymmetrical load.Secondly,asymmetrical upstream and downstream cable forces are used to control the main girder torsion caused by the transverse asymmetrical load.The influences of the unbalanced components along the cable-stayed bridge and the transverse direction of the bridge on the alignment of the main girder and the deviation of the main tower are analyzed.Finally,the method of reducing the secondary dead load of the railway is used to control the deviation of the main tower caused by the transverse asymmetrical load.The results show that the main girder torsion can be effectively controlled by the asymmetrical upstream and downstream cable forces.The transverse bending deformations generated by the unbalanced components along the cable-stayed bridge and the transverse direction of the bridge are basically consistent but opposite in direction,which is beneficial to reduce the transverse bending deformations of the main girder.The transverse deviation of the main tower can be effectively controlled by reducing the difference of the transverse asymmetrical load.