钢板梁桥腹板加劲肋焊缝疲劳开裂后的应力特征  

Stress characteristics of web-stiffener weld after cracking in steel plate girder bridges

作　　者：史国刚[1] 吉伯海[2] 陈壮壮 姚悦[2] 傅中秋[2] SHI Guogang;JI Bohai;CHEN Zhuangzhuang;YAO Yue;FU Zhongqiu(Highway Development Center of Jiangsu Province Transportation Department,Nanjing 210004,China;College of Civil and Transportation Engineering,Hohai University,Nanjing 210098,China)

机构地区：[1]江苏省交通运输厅公路事业发展中心,江苏南京210004 [2]河海大学土木与交通学院,江苏南京210098

出　　处：《河海大学学报（自然科学版）》2022年第2期69-75,共7页Journal of Hohai University(Natural Sciences)

基　　金：国家重点研发计划(2017YFE0128700);江苏省交通运输科技与成果转化项目(2019Y69)。

摘　　要：通过建立钢板梁桥节段有限元模型分析了主梁腹板与加劲肋连接焊缝部位的开裂特征,基于最不利车辆荷载位置分析了腹板间隙不同横向荷载位置下的正应力与剪应力特征,以及裂纹长度的变化对腹板面外变形的影响;通过对比不同裂纹长度时裂纹尖端和裂纹最深点的应力强度因子值,分析了裂纹长度对裂纹前缘的受力特征以及扩展速率的影响。研究结果表明:围焊端部受弯矩、剪力共同作用,裂纹沿着围焊端部时,以Ⅰ型裂纹为主,裂纹远离围焊端部向腹板扩展时,裂纹深度扩展加速;当裂纹贯穿腹板时,面外变形明显增大,腹板剪应力作用更为明显,裂纹扩展速率明显提升。A finite element model of the steel plate girder bridge segment was established to study the cracking characteristics of the stiffener-to-web weld.Under the most unfavorable position of vehicle load,the normal stress and shear stress characteristics of web gap under different transverse load positions and the influence of crack length on the out-of-plane deformation of web were analyzed.The stress intensity factors at the crack tip and the deepest point of crack were compared under different crack lengths,which revealed the influence of crack length on the stress characteristics and the growth rate of crack front.The results show that when the crack is along the side of the surrounding weld end under the joint action of bending moment and shear force,the crack is mainly of type I crack,and when the crack is far away from the side of the weld end and extends to the web,the crack depth grows faster.When the crack penetrates the web,the out-of-plane deformation of web increases obviously,the shear stress of the web becomes more obvious,and the crack propagation rate increases obviously.

关 键 词：钢板梁桥 加劲肋 焊缝 裂纹 腹板间隙 剪应力 应力强度因子 

分 类 号：U441.4[建筑科学—桥梁与隧道工程]