正交异性钢桥面板疲劳性能关键参数研究

Study on key parameters of fatigue performance of orthotropic steel bridge deck

社会现代化进程加快、交通量急剧增加使得正交异性钢桥面板的疲劳病害频繁发生,为节约全生命周期成本,前期设计时抗疲劳性能研究不可忽视,不同疲劳细节的疲劳性能各有不同,通过疲劳设计合理确定关键参数,使得设计效率得以提高,同时降低应力幅值、提高抗疲劳性能,对钢结构桥梁设计至关重要。通过有限元建立三维实体模型,选取2种典型的疲劳细节,加载2种疲劳荷载工况,分析加劲肋、横隔板开孔、横隔板及超高性能混凝土(UHPC)铺装不同参数对疲劳细节应力幅值的影响。研究表明:正交异性钢桥面板的加劲肋纵横交错、立体交叉、焊缝众多,其疲劳性能由各个疲劳细节、荷载工况、构造参数等联合控制;改变加劲肋尺寸和横隔板开孔形式对改善疲劳性能效果不显著且有可能增加反面效果;加密横隔板间距、增设UHPC层能显著地改善疲劳性能。正交异性钢桥面板构造按照中型U肋、Ⅱ型切口、横隔板间距2.5m至3m、UHPC-钢组合桥面板设计其疲劳性能最优。

The acceleration of social modernization and the rapid increase of traffic volume make the fatigue diseases of orthotropic steel bridge deck occur frequently.In order to save the whole life cycle cost,the research on fatigue resistance performance in the early design cannot be ignored.The fatigue performance of different fatigue details is different.It is very important for the design of steel structure bridges to reasonably determine the key parameters through fatigue design,so as to improve the design efficiency,reduce the stress amplitude and improve the fatigue resistance performance.A three-dimensional solid model was established by finite element method.Two typical fatigue details were selected and two fatigue load conditions were loaded.The effects of different parameters of stiffener,diaphragm opening,diaphragm and Ultra-High Performance Concrete(UHPC)pavement on the stress amplitude of fatigue details were analyzed.The research shows that the stiffeners of the orthotropic steel bridge deck are crisscross,three-dimensional intersection,and many welds.The fatigue performance is jointly controlled by various fatigue details,load conditions,and structural parameters.Changing the size of the stiffener and the opening form of the diaphragm plate has no significant effect on improving the fatigue performance and may increase the reverse effect;densifying the spacing of diaphragms and adding UHPC layers can significantly improve fatigue performance.The fatigue performance of orthotropic steel bridge deck is the best according to the design of medium-sized U-rib,type II notch,diaphragm spacing 2.5m to 3m and UHPC-steel composite bridge deck.