混合梁轨道专用斜拉桥自振特性研究

Study on Self Vibration Characteristics of Special Cable Stayed Bridge for Mixed Beam Track

以国内最大的混合梁轨道专用斜拉桥重庆高家花园大桥为研究对象,应用大型有限元软件建立全桥模型,采用子空间迭代法进行动力分析,得出该桥的自振频率和振型,并在此基础上研究结构参数对桥梁低阶频率和地震响应的影响。计算结果表明:双塔混合梁轨道专用斜拉桥辅助墩的设置对桥梁结构刚度分配十分有限,低阶自振频率及振型影响较小;主梁横向刚度对主梁侧弯的振动频率影响较大;半漂浮体系和固结体系振动频率基本相同,漂浮体系主梁侧弯振动频率较前两者小,且地震作用下结构响应十分显著;主梁及2期恒载对主梁低阶频率和地震响应较为显著,而对索塔的低阶振动频率影响较小。研究成果可为同类斜拉桥的设计及施工提供参考。

This paper, taking the largest rail - only mixed - beam cable stayed bridge in China,Chongqing Gaojia Huayuan Bridge as study object, uses large scale finite element software to set up awhole bridge model and subspace iterative method for dynamic analysis to obtain the self vibratingfrequency and vibrating type of this bridge. Based on this, this paper studied the influence of structuralparameters to bridge low order frequency and seismic response. Calculation results show that thearrangement of auxiliary piers in twin - tower rail - only mixed beam cable stayed bridge track has quitelimited influence on the distribution of bridge structural stiffness and has relatively small influence to loworder self vibrating frequency and vibrating type. The lateral stiffness of main beam has greater influence tovibrating frequency of the side bending of main beam. The vibrating frequency of half - floating system andfixed system is similar, while the main beam side bending vibrating frequency of floating system is smallerthan the former two, and the structural response under earthquake is quite significant. The main beam andphase 2 constant load has obvious response to main beam low order frequency and earthquake, while it hasrelatively small influence to low order vibrating frequency of the cable tower. The results may be used asreference for similar cable stayed bridge design and construction.