考虑热点应力的单索面斜拉桥正交异性钢桥面板疲劳性能研究  

Research on Fatigue Performance of Orthotropic Steel Deckof Single Cable Plane Cable-stayed Bridge Considering Welding Residual Stress

作　　者：张大牛 熊文 涂正浩 金辉 宋晓东 ZHANG Daniu;XIONG Wen;TU Zhenghao;JIN Hui;SONG Xiaodong(Department of Bridge Engineering,School of Transportation,Southeast University,Nanjing,Jiangsu 211189,China;Nanjing Urban Construction Management Group Co.,Ltd.,Nanjing,Jiangsu 210000,China)

机构地区：[1]东南大学交通学院桥梁工程系,江苏南京211189 [2]南京城市建设管理集团有限公司,江苏南京210000

出　　处：《公路工程》2023年第2期7-14,共8页Highway Engineering

基　　金：国家自然科学基金项目(52008093)。

摘　　要：正交异性钢桥面板因其抗震性能好、施工进度快等优点在现代大跨径桥梁建设工程中得到广泛应用,但同时又因其复杂的构造和传力路径,使焊接处在往复车辆荷载作用下产生严重的局部应力集中,最终导致疲劳损伤降低使用寿命。广泛存在于焊接结构内部的焊接残余应力在疲劳荷载作用下,会通过降低疲劳强度储备并促进初始裂纹的扩展严重影响结构的疲劳性能,进而降低结构的疲劳寿命,因此在正交异性钢桥面板的疲劳性能研究过程中应充分考虑到焊接残余应力的影响。以南京某单索面斜拉桥为背景工程,运用ANSYS有限元分析软件对该桥进行了多尺度建模分析。通过钢箱梁节段模型分析,分析横纵桥向应力影响范围为横桥向5个U肋×纵桥向2个横隔板间距,并根据规范中的车载疲劳模型Ⅲ确定了在疲劳细节正上方时加载为最不利加载工况。同时应用子模型技术法建立了精细实体模型,讨论了网格尺寸对应力分布与热点应力值的影响。最后得出厚度方向网格层数增至4层时对应的焊趾应力已达到数值收敛,外推区应力差值结果较为稳定,对于Solid95单元模型,厚度方向适合划分4层单元。Orthotropic steel bridge deck is widely used in modern long-span bridge construction due to its good seismic performance and fast construction schedule.At the same time,due to its complex structure and force transmission path,the welding place is under reciprocating vehicle load.Under the action,serious local stress concentration is produced,which will eventually lead to fatigue damage and reduce service life.Under the action of fatigue load,the welding residual stress that exists widely in the interior of the welded structure will seriously affect the fatigue performance of the structure by reducing the fatigue strength reserve and promoting the expansion of the initial crack,thereby reducing the fatigue life of the structure.Therefore,in the orthotropic steel bridge deck the effect of welding residual stress should be fully considered in the process of fatigue performance research.This paper takes a single-cable plane cable-stayed bridge in Nanjing as a background project,and uses ANSYS finite element analysis software to carry out multi-scale modeling and analysis of the bridge.Through the analysis of the steel box girder segment model,it is analyzed that the stress influence range of the transverse and longitudinal bridges is 5 U ribs in the transverse direction×2 diaphragm spacings in the longitudinal direction.The fatigue details are determined according to the on-board fatigue modelⅢin the specification.Loading directly above is the most unfavorable loading condition.At the same time,the sub-model technique method is used to establish a fine entity model,and the influence of the mesh size on the stress distribution and the hot spot stress value is discussed.Finally,it is concluded that when the number of grid layers in the thickness direction increases to 4 layers,the corresponding weld toe stress has reached the numerical convergence,and the result of the stress difference in the extrapolation zone is relatively stable.For the Solid95 element model,the thickness direction is suitable for dividing 4 lay

关 键 词：单索面斜拉桥 正交异性桥面板 疲劳 焊接残余应力 

分 类 号：U448.27[建筑科学—桥梁与隧道工程]