空间缆斜拉—悬索协作桥合理成桥状态确定方法的研究

Research on Method for Determining Reasonable Completion State of Cable-stayed Suspension Collaborative Bridge with Spatial Main Cable

将斜拉—悬索协作体系拆分为斜拉子系统和悬索子系统,先分别确定两子系统的成桥状态再组合起来形成协作体系,这样易导致协作体系的成桥状态与子系统的受力状态不一致。基于无应力状态法的思路,保证组合前后受力状态一致的核心是控制各构件无应力状态量保持不变。分析了斜拉子系统和悬索子系统中缆索及斜拉索索单元无应力长度的计算方法,并通过温度补偿法抵消主梁和主塔的轴向压缩变形,实现对塔、梁单元无应力长度的修正;通过斜拉子系统成桥状态竖向位移在协作体系中设置预拱度,避免了主梁线形的变化对索力的影响;探讨了协作体系交叉区斜拉索与吊索索力的竖向分力的合理分配比例,为协作体系的拆分提供依据。形成了一套斜拉—悬索协作体系合理成桥状态的实现方法,并以某独塔空间缆斜拉—悬索协作桥为例对该方法进行了验证。结果表明,该方法解决了将子系统组合为协作体系时结构状态偏离目标状态的问题,实现了将复杂的协作体系拆分为悬索系统、斜拉系统进行计算的目标。

The cable-stayed suspension bridge system is divided into cable-stayed subsystem and suspension subsystem,and the reasonable completion state of the two subsystems are determined respectively,and then combined.It is easy to appear that the reasonable completion state of the cooperative system is inconsistent with that of the subsystem.Based on the idea of the stress free state method,the core of ensuring the consistency of the stress state between the collaborative system and the two subsystems is to control the constant stress free state of each component.The calculation method of unstressed length of cable-stayed,main cable and sling element in cable-stayed subsystem and suspension subsystem are studied.The temperature compensation method is discussed to offset the axial compression deformation of the main beam and the main tower,so as to correct the unstressed length of the tower and beam element.The camber is set in the cooperative system according to the vertical displacement of the cable-stayed subsystem in the form of the reasonable completion state,avoiding the influence of the change of the main beam alignment on the cable force.The reasonable distribution ratio of the vertical component of the cable force in the intersection area of the cooperative system is discussed,which provides the basis for the splitting of the cooperative system.A set of methods to realize the reasonable completion state of cable-stayed suspension system is formed.A spatial cable-stayed suspension bridge with single tower is taken as an example.The results show that this method can solve the problem that the state of the collaborative bridge deviates from the target state in the case of simple combination,and can easily realize the reasonable completion target state in combination with the characteristics of the collaborative bridge.