摘要
研究目的:为研究高速铁路大跨连续钢桁梁柔性拱桥正交异性钢桥面板疲劳细节的局部受力,本文以银西高铁银川机场黄河特大桥为背景,建立横梁弧形切口以及U肋与顶板连接焊缝两处疲劳细节的精细化有限元模型,分析列车移动荷载作用下疲劳细节处的应力分布,并对比分析不同弧形切口形状和横梁腹板厚度对疲劳细节局部应力的影响规律。研究结论:(1)正交异性钢桥面的U肋-横梁位置的弧形切口处在移动活载下容易出现应力集中,且弧形切口起始处与弧形切口自由边所对应的最不利活载位置不同,在轨枕横向两侧端部下方的横梁弧形切口起始处以及弧形切口自由边容易出现最大主应力;(2)横梁板厚对弧形切口自由边的主压应力影响最大,且随板厚增大该处主压应力减小,对本工程当板厚由16 mm增加至20 mm时,主压应力减小幅度超过20%;(3)不同弧形切口形状对疲劳细节的局部应力也有较大影响,与原设计切口形状相比,日本设计规范所推荐切口形状的主应力极值最小;(4)为提高正交异性钢桥面板的疲劳特性,对U肋-横梁疲劳细节进行局部构造优化是必要的,研究成果对同类型结构的优化设计具有理论指导意义。
Research purposes: In order to study the local stress of fatigue details of orthotropic steel deck of high-speed railway long-span continuous steel truss flexible arch bridge,based on Yinchuan airport Yellow River Bridge of Yinchuan-Xi’an high-speed railway,a refined finite element model of two fatigue details,i. e. beam arc incision and U-rib roof joint weld,is established. The stress distribution of fatigue details under the action of train moving load is analyzed. The influence of different types of arc incision and web thickness on the local stress of fatigue details is analyzed.Research conclusions:(1) The arc incision at the U-rib-beam position of orthotropic steel bridge deck is prone to stress concentration under moving live load,and the starting point of arc incision is different from the most unfavorable live load position corresponding to the free edge of arc incision. The maximum main stress is easy to appear at the starting point of arc incision and the free edge of arc incision under the ends of both lateral sides of the sleeper.(2) The thickness of the crossbeam has the greatest influence on the main compressive stress of the free edge of the arc incision,and the main compressive stress decreases with the increase of the slab thickness. For this project,when the slab thickness increases from 16 mm to 20 mm,the main compressive stress decreases by more than 20%.(3) Different arc incision shapes also have a great impact on the local stress of fatigue details. Compared with the original design,the incision shape that Japanese code recommended has the minimum value of the principal stress.(4) In order to improve the fatigue characteristics of orthotropic steel bridge deck,it is necessary to optimize the fatigue details of U-rib beam.The research results have theoretical significance for the optimal design of the same type structure.
作者
蔺鹏臻
何志刚
LIN Pengzhen;HE Zhigang(Key Laboratory of Road Bridge and Underground Engineering of Gansu Province,Lanzhou Jiaotong University,Lanzhou,Gansu 730070,China)
出处
《铁道工程学报》
EI
北大核心
2020年第5期18-22,29,共6页
Journal of Railway Engineering Society
基金
国家自然科学基金重大项目(11790281)
国家自然科学基金项目(U1934205)。
关键词
正交异性钢桥面板
横梁弧形切口
疲劳细节
局部应力
优化
orthotropic steel bridge deck
arc incision of beam
fatigue details
local stress
optimization
