中文摘要：

为给车辆荷载作用下钢箱梁的抗疲劳设计提供依据，对钢箱梁局部构造对其关键焊缝疲劳性能的影响进行研究。采用有限元方法计算了钢箱梁焊缝在单轮移动荷载下的应力曲线，在此基础上分析了纵向加强桁架对钢箱梁关键焊缝疲劳应力范围和疲劳损伤的影响。计算、分析表明，纵向加强桁架增大了钢箱梁临近区域顶板的竖向刚度，并改变了其临近焊缝细节的受力状态，这使得纵向加强桁架附近焊缝的疲劳应力和疲劳损伤远小于相同位置无纵向加强桁架的钢箱梁焊缝的值；局部构造差异对钢箱梁桥面关键焊缝疲劳性能的影响明显，在钢箱梁抗疲劳设计中应予以考虑。

英文摘要：

To provide basis for the fatigue design of the steel box girder under the action of vehicle load, the effect of the local structure of the girder on the fatigue performance of the criti- cal welding seams of the girder was studied. The finite element method was used to calculate the stress curves of the welding seams of the girder under the single wheel moving load and on the ba- sis of the calculation, the effect of the longitudinal stiffening truss arranged in the girder on the stress ranges and fatigue damages of the critical welding seams was analyzed. The results of the calculation and analysis show that the longitudinal stiffening truss increases the vertical stiffness of the top plate of the girder in the adjacent area of the truss and also changes the force conditions of the welding seam details nearby, which makes the fatigue stress and fatigue damages of the welding seams nearby far less than those of the welding seams in the same position without the stiffening truss. The effect of the differences of the local structure on the fatigue performance of the critical welding seams in the girder deck is significant and in the fatigue design of the girder, the effect should be appropriately taken into account.