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本文针对模数式伸缩缝中梁疲劳断裂问题展开分析,以青银(青岛至银川)高速公路河北段桥梁用到的模数式伸缩缝为原型建立模数式伸缩缝中梁疲劳分析有限元模型,并选取国外BS5400规范及AASHTO规范对其进行疲劳寿命评估,对比分析整体安装及半幅安装焊接为整体两种施工方法下的疲劳寿命,并分析了相邻支撑横梁间距、中梁截面尺寸、钢材弹性模量及半幅施工时焊缝位置对中梁疲劳寿命的影响。结果表明:模数式伸缩缝中梁应力状态对车辆轮载比较敏感,应采用轮载作用次数来评估其疲劳寿命;半幅安装焊接为整体的更换施工方法对中梁疲劳寿命影响显著,BS5400规范及AASHTO规范下疲劳寿命均降低超过50%;支撑横梁间距及中梁截面尺寸为中梁疲劳寿命的显著影响因素,而钢材弹性模量为一般影响因素,焊缝位置在一定范围内显著影响中梁疲劳寿命。
In this paper, the problem of fatigue fracture of modular expansion joints was analyzed. The fatigue analysis finite element method of finite element analysis was established using the modular expansion joints used in bridge between Hebei and Yinchuan of Qingyin (Qingdao-Yinchuan) Model, and select the foreign BS5400 norms and AASHTO norms fatigue life assessment, comparative analysis of the whole installation and half installation welding as a whole two kinds of construction methods of fatigue life and analysis of the adjacent support beam spacing, beam cross-section size, Effect of Steel Elastic Modulus and Weld Position on Fatigue Life of Middle Beam in Half Construction. The results show that the stress state of the middle beam of the modular expansion joint is sensitive to the wheel load of the vehicle, and the fatigue life should be evaluated by the number of wheel loads. The replacement construction method with the half installation and welding as a whole has a significant impact on the fatigue life of the middle beam. And AASHTO standard fatigue life are reduced by more than 50%; support beam spacing and beam cross-section size of the fatigue life of the beam significant impact factors, and steel elastic modulus as a general factor, the weld position within a significant impact Beam fatigue life.