横梁腹板切口形状对正交异性钢桥面板疲劳性能的影响研究

Influence of Crossbeam Web Cutout Shape on Fatigue Performance of Steel Orthotropic Deck

在正交异性钢桥面板中,横梁腹板与纵肋连接部位及横梁腹板切口边缘处较容易发生疲劳开裂,为了弄清横梁腹板切口形状对这两个构造细节疲劳性能的影响规律,采用有限单元法,通过在3种作用下采用不同切口形状的正交异性板各考察点主拉应力或面外应力比率的对比研究,得出以下结论:(1)在剪切作用下,切口形状对纵肋与横梁连接部位的应力影响不大,切口边缘半径对横梁切口边缘拉应力影响很大;(2)在支撑作用下,切口尺寸越大,纵肋与横梁连接部位的应力越大;(3)在面外作用下,切口尺寸越大,横梁对纵肋的面外转动变形约束越小,面外应力比率越小。

Fatigue cracks are prone to appear near the joint of crossbeam web with rib and the edge of web cutout in orthotropic steel bridge deck. In order to understand how cutout shape of crossbeam web affects the fatigue performance of the two details, finite element method is applied. A comparative study is conducted on principal tensile stresses or out-of-plane stress ratio at all investigated points of orthotropic steel bridge deck with different cutout shapes under three actions. Conclusions are obtained as follows：1） under the action of shearing effect, cutout shape has little effect on stress of the joint between crossbeam web and rib, while radius of cutout edge has great effect on stress of edge of cutout;2） under the action of supporting effect, the larger the size of the cutout, the bigger the stress of the joint between crossbeam web and rib;3） under the action of out-of-plane effect, the larger the size of the cutout, the smaller the constraint effect of the crossbeam towards, the rotation deformation of the rib, the smaller the out-of-plane stress ratio.