超大跨径半漂浮体系双塔双索面混合梁斜拉桥抗风分析

Wind Resistance Analysis of Long-span Hybrid Girder Cable-Stayed Bridge with Double Towers and Double Cable Planes Semi-Floating System

超大跨径半漂浮体系双塔双索面混合梁斜拉桥常被用于航道等级高、水深条件复杂而无法设置大规模地锚的大江(河、海)中,该类桥梁结构刚度随跨度增大而降低,导致其在风力作用下的变形较大而容易产生震动,因此其抗风稳定问题显得尤为重要。为了研究此类斜拉桥的抗风稳定问题,以主跨1200m的超大跨度斜拉桥设计方案为例,采用MIDAS/Civil建立其空间有限元模型,从最大悬臂状态和成桥状态对结构的动力特性和抗风稳定性进行分析。结果表明,该桥主梁颤振临界风速均超过其颤振检验风速,满足规范要求。

As a cable system, continuous semi-floating double-pylon hybrid girder cable-stayed bridge is often used in bridges with increasing traffic volume, overload and limited deck width. As the span of this type of bridge increases gradually, the structure becomes more flexible, and its deformation under wind force is larger and more vibration- prone, so the problem of wind-resistant stability becomes increasingly important. In order to further analyze the wind-resistant stability of this kind of cable-stayed bridge, this paper takes the design scheme of a long-span cable- stayed bridge with a main span of 1200m as an example, and MIDAS/Civil is used to establish its spatial finite element model, and the wind-resistant stability and dynamic characteristics of the structure are analyzed from the maximum cantilever state and the completed bridge state. It is concluded that the critical wind speed of flutter of the main girder of the bridge exceeds its flutter test wind speed and meets the requirements of the code.