钢—混组合斜拉桥长期力学行为随机性分析

Randomness Analysis of Long-term Mechanical Behavior of Steel-concrete Composite Cable-stayed Bridge

摘要:

斜拉桥在服役期间的长期力学行为是其养护维修必须考虑的问题。考虑到混凝土强度和环境相对湿度的随机性，建立了有限元随机分析模型，研究拉索索力、主梁挠度和塔顶偏移量的随机时变特性，初步建立了拉索索力增量与桥梁变形之间的映射关系。结果表明，混凝土强度和环境相对湿度的随机性对斜拉桥跨中挠度和主塔塔顶偏移量的影响较大，对拉索索力的影响较小；拉索索力分别服从正态分布和韦伯分布，跨中挠度和塔顶偏移量服从韦伯分布；跨中挠度、塔顶偏移量分别与拉索索力增量呈线性相关关系。因此，进行斜拉桥收缩徐变效应分析时，需考虑参数随机性带来的影响。

Abstract:

The long-term mechanical behavior of cable-stayed bridges under service is an issue that must be considered in the maintenance. Considering the randomness of concrete strength and relative environmental humidity, a finite element analysis model of randomness is established to study the random time-varying characteristics of cable forces, girder deflections and offsets of the pylon top. The mapping relationship between the increment of the cable force and the deformation of the bridge has been initially established. The results show that the randomness of the concrete strength and the relative environmental humidity has a significant impact on the mid-span deflections of the cable-stayed bridges and the offsets of the main pylon top, but has a relatively small impact on the cable forces. The cable forces follow the normal distribution and the Weibull distribution respectively, and the mid-span deflections and the offsets of the pylon tops follow the Weibull distribution. Both the mid-span deflection and the offset of the pylon tops exhibit a linear correlation with the cable force increments, respectively. Therefore, when analyzing the shrinkage and creep effects of cable-stayed bridges, it is necessary to consider the influence of the parameter randomness.