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U形肋加劲板是构成钢箱梁顶板、底板的主要板件,U形肋腹板与被加劲板局部失稳是其两种主要失稳破坏模式。为研究U形肋加劲板的局部稳定性能,分别设计并制作了U形肋腹板与被加劲板壁板两组局部稳定试件,并考虑U形肋腹板宽厚比、被加劲板宽厚比以及U形肋翼缘与腹板间弯曲半径变化。通过轴压试验得到了U形肋加劲板的局部失稳破坏模式、稳定承载力、应力-位移曲线以及局部稳定折减系数。试验研究表明:随着局部板件宽厚比的增大,试件由强度破坏转变为失稳破坏,且失稳破坏特征表现得越明显。当板件宽厚比不小于22.5时,宽厚比较大的板件先于其他板件失稳。U形肋腹板与翼缘之间弯曲半径增大时,U形肋腹板宽度及宽厚比变大,导致U形肋腹板稳定承载力降低。将试验结果与公路钢桥规范中的稳定系数曲线对比发现,对于钢桥规范中的稳定曲线,采用钢材屈服强度计算得到的板件稳定承载力明显小于试验值,而采用抗拉强度计算得到的板件稳定承载力接近试验值,说明采用钢桥规范计算U形肋加劲板稳定承载力,其安全系数和钢材的抗拉强度与屈服强度比值相当。
The U-shaped rib stiffened plate is the main plate that forms the roof and bottom of the steel box girder. The local instability of the U-shaped ribbed web and the stiffened plate is the two main failure modes. In order to study the local stability of U-rib stiffened plate, two sets of partially stabilized specimens of U-ribbed stiffened panel and stiffened panel were designed and fabricated. Considering the aspect ratio of U-shaped ribbed web, Bending Radius Between U-shaped Ribs and Webs. The local buckling failure mode, stable bearing capacity, stress-displacement curve and local stability reduction coefficient of U-shaped stiffened plate are obtained by axial compression test. Experimental results show that with the increase of local aspect ratio, the specimens change from strength failure to failure failure, and the instability failure characteristics are more obvious. When the ratio of plate thickness to thickness is not less than 22.5, the plate with large thickness and thickness will be unstable before the other plates. When the bending radius between the U-shaped web and the flange increases, the width and aspect ratio of the U-shaped rib web become larger, which leads to the decrease of the stable bearing capacity of the U-shaped web. Comparing the test results with the stability coefficient curve in the highway steel bridge code, it is found that for the stability curve in the steel bridge code, the steady bearing capacity of the steel plate calculated by the yield strength of the steel is obviously less than the test value, and the tensile strength The steady bearing capacity of the plate is close to the test value, which shows that the stability bearing capacity of the U-shaped stiffened plate is calculated by the steel bridge code. The safety factor and the ratio of the tensile strength and the yield strength of the steel are equivalent.