实腹式型钢混凝土梁疲劳设计方法研究

STUDY ON FATIGUE DESIGN METHOD FOR SOLID-WEB STEEL REINFORCED CONCRETE GIRDERS

  • 摘要: 目前国内外规范均未涉及实腹式型钢混凝土(SRC)梁的疲劳设计,这无疑限制了SRC结构在疲劳荷载工况下的应用。该文结合已有的一系列SRC梁疲劳性能试验研究与数值分析结果,提出了SRC梁的疲劳设计方法,可为实际工程设计提供参考。通过对SRC梁中各关键组件分别进行疲劳设计来保证整个SRC梁的安全性。其中,SRC-H钢梁作为SRC梁中最重要的组件,通过修正现行规范中已有纯H形钢梁疲劳设计S-N曲线进行疲劳设计,修正系数基于对大量数据的回归分析得到。对于SRC梁受拉纵筋,根据试验数据拟合出疲劳设计S-N曲线,并考虑应力比的影响。对于SRC梁受压区混凝土,尽管在试验中未发生疲劳破坏,偏于保守地,直接采用现行混凝土结构疲劳设计规范中的方法进行疲劳设计。最后,根据已有试验结果对该文的疲劳设计方法进行了验证,结果表明该文的设计方法是合理可靠的。

     

    Abstract: At present, the fatigue design for solid-web steel reinforced concrete (SRC) girders is not specified in domestic and foreign codes, which undoubtedly limits the application of SRC structures under fatigue loading conditions. Based on a series of experimental and numerical results of fatigue behaviors of SRC girders, this study proposes a fatigue design method for SRC girders, which can provide a reference for practical engineering design. The safety of the whole SRC beam is ensured by carrying out fatigue design for each key component inside SRC girder separately. Among them, the SRC-H-steel, as the most important component inside SRC girders, was designed by modifying the S-N fatigue curve for existing bare H-steel beam in current codes, and the correction coefficient was obtained upon the regression analysis of a large amount of data. For the longitudinal tensile bars inside SRC girders, the fatigue design S-N curve was fitted according to experimental data, and the influence of stress ratio was considered. For the concrete in compression zone of one SRC girder, although no fatigue failure occurred in experimental investigations, the existing methods in the current fatigue design code for concrete structures are adopted conservatively. Finally, the fatigue design method proposed is verified according to previous experimental results, which shows that the design method is reasonable and reliable.

     

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