【摘要】 通过对某实桥正交异性钢桥面板疲劳裂纹的实地调查,总结正交异性钢桥面板疲劳裂纹主要分布形态,分析正交异性桥面板疲劳开裂原因主要是:在车辆荷载作用下桥面板产生的局部竖向变形、桥面板与U肋之间产生的相对转角使焊缝根部因受拉应力过大而导致疲劳开裂;纵向U肋与横隔板刚度不同产生的次应力、U肋的偏转和竖向变形使过焊孔处横隔板受拉开裂;纵向U肋产生的纵向弯矩引起嵌补段裂缝。各主要受力板件的厚度过薄、横隔板过焊孔的形状以及横隔板的拼接方式也会加速疲劳开裂。针对既有正交异性钢箱梁桥的典型病害,提出了正交异性钢桥面板关键部位抗疲劳特性的改进措施:提高桥面板竖向刚度并改进U肋与桥面板的焊接工艺,在横隔板位置处的U肋内部设置小内横隔,U肋嵌补段改用螺栓连接等。更多还原

【Abstract】 According to the field investigation of fatigue cracks in bridge’s orthotropic deck,the distribution of fatigue cracks in orthotropic deck is discussed.The major causes of fatigue cracks in orthotropic deck are:(1) under the action of vehicle loads,the deck generated partial vertical deformation;(2) the relative angle between deck plate and U ribs generated fatigue cracks at the root of welds because of overlarge tensioning stress;(3) the secondary stresses caused by different stiffnesses between longitudinal U ribs and diaphragm,rotation and vertical deformation of U ribs lead the diaphragm cracks by tension at the welding;(4) longitudinal bending moment generated by U ribs gave rise to the vertical cracks in inlaying section;(5) little thickness of plates,the shape of welding pass holes and the connection of the diaphragm accelerated fatigue cracks.To cope with the typical disease of the existing orthotropic steel box girder bridges,the control measures are proposed to improve the key point’s anti-fatigue properties,such as increase the vertical stiffness of the bridge deck,improve the welding technique between U-ribs and deck plates,set up small diaphragm in U rib at the diaphragm,and use bolt connection at the inlaying section of U ribs and so on.更多还原