【摘要】 研究目的:随着钢桥的重载化和整体化,桥梁钢结构中出现了较多无法明确其名义应力、现行规范也无对应细节的复杂构造。在实践中,对于该类细节多采用原形疲劳试验的方法进行验证。但疲劳试验的长周期和高费用,制约了该类细节的快速应用和推广。本文旨在用热点应力进行钢桥疲劳检算,实现在设计阶段尽可能准确地评估复杂细节的疲劳性能的目的。研究结论:本文分析计算了多种接头的热点应力集中系数,采用热点应力集中系数法推导了钢桥疲劳检算的热点应力Shot～N曲线。BS5400规范多种构造细节的名义应力疲劳强度与导出的热点应力疲劳强度的对比表明,热点应力疲劳强度明显比名义应力法的离散性小,热点应力法适合桥梁工程应用。更多还原

【Abstract】 Research purposes:As steel bridges are becoming more heavy-loaded and integrative,many complicated structures that their nominal stress can not be identified and their details can not corresponded with the existing design codes have happened in the steel bridge structure.In practice,the prototypical fatigue tests are usually done to validate these structures.However,the fatigue tests need long time and high cost and it restricts the fast and wide application of the fatigue test to validate the details of these structures.In order to accurately evaluate the fatigue behaviours of these details of the complicated structure,the study was done on the application of the hot spot stress in evaluating the bridge fatigue. Research conclusions:The analysis of the concentration factors of the hot spot stress of many kinds of joint was made and the shs-N curve of the hot spot stress for checking the steel bridge fatigue was deduced by using the concentration factors of the hot spot stress.The comparison of the fatigue strength of nominal stress of the many kinds of structure details stipulated in BS5400 with the deduced fatigue strength of hot spot stress showed the deduced fatigue strength of hot spot stress was obviously less than the discreteness obtained with the nominal stress method.So the hot spot stress method is available for bridge construction.更多还原