Trapezoidal corrugated steel webs under panting fatigue are represented by repeated cyclical out-of-plane deflections of their subpanel with mixed-mode cracks. Compared to stiffened flat webs, notable fatigue crack formation could take place along with local deflection. Fatigue tests were conducted for nine composite girders with slender webs and varied corrugation dimensions. Nearly all test girders showed notable local and interactive shear buckling at the corrugated web panel and the panting fatigue cracks are formed under repeated cyclical deflection while the compression and tension flanges remain intact. Fatigue cracks are initiated at the junction between the vertical (longer) edge of the subpanel and the boundary of the out-of-plane deflection region. The crack propagation paths appear to deviate from the original vertical edge due to buckling induced out-of-plane deflection under mixed-mode stress condition. The test results demonstrate that the Category B’ and Category E suggested by the AASHTO LRFD bridge fatigue design provisions related to the principal stress range and the nominal membrane shear stress range respectively can be considered for the prediction of the fatigue life of trapezoidal Corrugated steel webs in test girders. An appropriate allowance of both the shear stress along the vertical web edge and tension stress from the diagonal plastified tension band is given for the mixed-mode stress intensity factor. The proposed fatigue life prediction allowing for mixed-mode crack growth mostly compares well with test results and its further improvement for the case with higher web panel slenderness ratio is discussed.

气喘疲劳下的梯形波纹钢腹板由其子面板的反复周期性的平面外偏斜和混合模式裂纹所代表。与平直的腹板相比，明显的疲劳裂纹会随着局部挠曲而发生。对九个具有细长腹板和不同波纹尺寸的复合材料梁进行了疲劳试验。几乎所有的试验大梁在波纹腹板处都表现出明显的局部和交互式剪切屈曲，并且在反复的周期性挠曲下形成气喘吁吁的疲劳裂纹，而压缩和拉伸法兰则完好无损。疲劳裂纹在子面板的垂直（较长）边缘与平面外偏转区域的边界之间的接合处引发。由于在混合模式应力条件下屈曲引起的面外偏转，裂纹的传播路径似乎偏离了原始的垂直边缘。测试结果表明，AASHTO LRFD桥梁疲劳设计规定所建议的B'级和E级分别可用于预测梯形波纹钢腹板的疲劳寿命，分别涉及主应力范围和标称膜剪切应力范围。在测试大梁中。对于混合模式应力强度因子，给出了沿垂直腹板边缘的剪应力和来自对角塑性拉伸带的拉伸应力的适当余量。