横隔板及几何特征对钢箱梁畸变效应的影响

Influences of Diaphragm Plate and Geometric Characteristics on Distortion Effect of Steel Box Girder

研究目的：由于钢箱梁的顶、底板及腹板均较薄，在偏心荷载作用下，截面变形易引起畸变应力而导致局部屈曲和腹板压皱等现象。工程应用上，在梁内设置一定数量的横隔板来约束钢箱梁的畸变变形，以求减少钢箱梁畸变效应。此前已有少量文献就横隔板对钢箱梁的畸变效应进行过研究，但未对钢箱梁在不同的隔板数量、高跨比、宽高比下进行综合分析，使其成果具有一定的局限性。因此，本文在此基础上通过有限元软件就简支钢箱梁的畸变效应进一步分析，并提出了横隔板的数量及箱梁的几何特征参数对钢箱梁畸变效应的影响。研究结论：（1）当箱梁为窄箱梁，即宽高比约等于1．5时，箱梁跨中畸变翘曲最大正应力随横隔板数量增多而增大，此时跨内横隔板设3～5道为宜；（2）当箱梁为宽箱梁，即宽高比约等于4．5时，箱梁跨中畸变翘曲最大正应力随横隔板数量增多而减小，此时跨内横隔板的设置9道为宜；（3）计算结果对同类桥梁的设计具有参考价值。

Research purposes ： As the roof plate, bottom plate and web of steel box girder are rather thin, the distortion stress easily happens due to their deformations in the sections under the effect of the eccentric load, resulting in the local buckling and web crinkling. In engineering application, a certain amount of diaphragm plates are installed in the box girder to restrain the distortion deformation and reduce the distortion effect on the box girder. There is a small number of papers to study the effect of the diaphragm plate on the distortion deformation of the steel box girder, but these papers do not research the distortion effects on steel box girder under the conditions of various amounts of the diaphragm plates, different depth - span ratios and aspect ratios, so thees results have certain limitations. Based on these results, this paper analyzes the distortion effect on the simply - supported thin - walled steel box girder with the finite element model and discusses the influences of the diaphragm number and geometric parameters on distortion effect of the steel box girder. Research conclusions： （ 1 ） The maximum normal stress of mid - span ＂s distortion warping of the steel box girder fincreases with increase of diaphragm amount, when the box girder is narrow one with the aspect ratio of being approximately equal to l. 5. In this case, the diaphragm plates of 3 - 5 ways should be installed in the span. （2） When the box girder is wide one with the span distortion warping of steel box plates of 9 ways should be installed bridge. aspect ratio of being approximately equal to 4.5, the maximum normal stress of mid - girder decreases with increase of the diaphragmamount. In this case, the diaphragm in the span. （3） The results can provide the reference to the design of the same type