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公路桥梁的疲劳设计准則,最近已根据疲劳方面的最新研究作了修订。本文以类似方法,为重新评定铁路桥梁的疲劳准则作一尝试。并对规定在设计中应用的应力循环的合理次数,提出一般原则和公式。因列车荷载造成桥梁杆件的应力循环显著少于单个载重卡车在公路桥上所造成的,同样,出现最大设计应力频率也较小,因而与公路桥相比疲劳在铁路桥梁中是较不严重的问题。估算铁路桥梁的主要杆件和纵梁的设计应力循环的等效次数表明,现行铁路桥梁的疲劳规定可能过于保守。
The fatigue design guidelines for highway bridges have recently been revised based on recent studies on fatigue. In a similar way, this paper attempts to re-evaluate the fatigue criteria of railway bridges. And set forth general principles and formulas for a reasonable number of stress cycles that are specified in the design. As a result of train loading, the stress cycling of bridge members is significantly less than that of a single truck on a highway bridge, and similarly, the maximum design stress frequency is also small, so fatigue is less severe in railway bridges than in highway bridges The problem. The estimated number of equivalent stress cycles for the design of the main bars and stringers of the railway bridges suggests that the existing fatigue regulations for the railway bridges may be too conservative.