钢箱梁U型肋加劲板受压稳定极限承载力影响因素分析
Analysis on influence factors of stability ultimate bearing capacity of U-rib stiffened plate of steel box girder

钢箱梁因其刚度大、自重轻等优点被广泛应用于桥梁工程中。为了研究钢箱梁U型肋加劲板的受压稳定极限承载力，采用考虑材料和几何双重非线性的有限元法对9块加劲板试件的稳定极限承载力进行了分析，并与试验结果进行了对比验证；采用经过验证的有限元方法分析了母板宽厚比、加劲肋与母板对加劲板形心抗弯刚度比、初始几何缺陷、焊接残余应力共4组参数对U型肋加劲板稳定极限承载力的影响规律。研究结果表明：有限元计算结果与试验结果吻合较好，验证了有限元模拟方法的正确性；母板宽厚比、加劲肋与母板对加劲板形心抗弯刚度比对U型肋加劲板稳定极限承载力的影响显著，并具有良好的规律性；初始几何缺陷对U型肋加劲板稳定极限承载力的影响与加劲板特征值分析的1阶屈曲模态相关，对于1阶屈曲模态为母板局部屈曲的U型肋加劲板而言，当初始几何缺陷达到母板宽度的1/100时，其稳定极限承载力的降幅高达28.34%；焊接残余应力对U型肋加劲板稳定极限承载力的影响也较为显著，考虑焊接残余应力后，U型肋加劲板稳定极限承载力的降幅最大可达到11.1%。研究结果可为钢箱梁U型肋加劲板的进一步研究和推广应用提供参考。
Steel box girder was widely used in bridge engineering due to its high stiffness, light weight and other advantages. In order to investigate the stability ultimate bearing capacity of U-rib stiffened plate under compression, finite element method (FEM) which took geometrical and material nonlinearity into account was used to analyze the stability ultimate bearing capacity of 9 specimens of stiffened plate, and the validity of FEM was verified by comparing the FEM results with the experimental results. Furthermore, a detailed parametric study by using the verified FEM was carried out to determine the influence of width-height ratio, the stiffness ratio between bending stiffness of stiffener to the overall centroid and that of parent plate to the overall centroid, initial geometric imperfections and residual stress on stability ultimate bearing capacity of U-rib stiffened plate. The results show that finite element calculation results are in good agreement with test results, which verifies the correctness of the finite element simulation method. Width？？height ratio and ratio between bending stiffness of stiffener to the overall centroid and that of parent plate to the overall centroid, affect the stability ultimate bearing capacity of U-rib stiffened plate significantly and have a good regularity. Influence of initial geometric imperfections on the stability ultimate bearing capacity of U-rib stiffened plate has correlation with the first order buckling shape of U-rib stiffened plate. For U-rib stiffened plate with the first order local buckling of parent plate, when initial geometric imperfection value reaches to 1/100 of the width, the stability capacity of U-rib stiffened plate reduces by 28.3%. Residual stress also influences the stability ultimate bearing capacity of U-rib stiffened plate significantly. The stability ultimate bearing capacity of U-rib stiffened plate maximally reduces by 11.1% after considering residual stress. The research results can provide reference for further research and application of U-rib stiffened plate of steel box girder