【摘要】 铁路桥跨结构的横向振幅关系到桥梁的正常使用性能和行车安全性,它不仅与梁体本身特性有关,而且受到基础-墩-梁组合体系自振特性的影响。文中应用能量法推导考虑基础弹性约束的墩梁体系横向基频的解析公式,并将其和有限元软件的计算结果进行比较,验证解析公式的正确性。结果表明:在进行基础-墩-梁体系横向自振特性分析时可以忽略墩底承台的影响;墩梁质量比越大的体系,其横向基频对基础弹性约束越敏感。提出基础墩梁体系频率敏感性指标的概念,分别针对重力式桥墩、轻型墩桥梁,对比分析增加墩柱刚度和基础刚度对提高体系横向基频的有效性,为工程设计提供参考。更多还原

【Abstract】 The transverse vibration amplitude of railway bridges has significant impact on serviceability and running safety. It is not only related to the bridge structure,but also influenced by the free vibration characteristic of the foundation-pier-beam system. The analytical formula of the transverse fundamental frequency for pier-beam system is deduced by energy method considering elastic constraint of the foundation,followed by comparison with finite element method. Results show that the influence of the pile cap can be ignored in free vibration analysis of the foundation-pierbeam system,while that of the elastic constraint is far more significant,especially when piers have larger mass.Moreover,the sensitive index of frequency is established for the system,which could be used to assess the efficiency of different methods( raising the rigidity of pier or the foundation) to increase the system’ s transverse fundamental frequency. Finally,case studies on a gravity-pier bridge and a light-pier bridge are presented to provide reference for future design.更多还原