钢箱梁横隔板弧形切口疲劳性能及构造优化研究  

Fatigue Performance and Structural Detail Optimization of Arc-Shape Cutouts in Diaphragm of Steel Box Girder

作　　者：柯璐[1] 林继乔 李传习[1] 刘永明[3] 陈卓异[1] 

机构地区：[1]长沙理工大学桥梁工程安全控制教育部重点实验室,湖南长沙410114 [2]佛山市路桥建设有限公司,广东佛山528303 [3]亚利桑那州立大学,坦佩85287

出　　处：《桥梁建设》2017年第5期18-23,共6页Bridge Construction

基　　金：国家重点基础研究发展计划(973计划)项目(2015CB057701);国家自然科学基金项目(51378080);广东省交通厅科技项目(201602010)~~

摘　　要：横隔板弧形切口处疲劳开裂是钢箱梁的主要疲劳病害之一,为提高该细节的疲劳性能,确定其合理构造形式,以某悬索桥(加劲梁采用钢箱梁)为背景,建立钢箱梁节段有限元模型进行疲劳应力分析,基于P-M线性积伤律和Eurocode 3提供的S^N曲线计算其疲劳寿命,比较6种国内外常用弧形切口的疲劳性能,并分析切口半径和横隔板厚度对疲劳应力的影响。结果表明:轮载作用下横隔板弧形切口处存在明显的拉、压应力集中区;疲劳裂纹萌生于压应力集中区,裂纹扩展方向与主压应力方向基本垂直;弧形切口的形式显著影响其疲劳性能,国内外典型孔型中,圆弧+直线方案(孔型4)为刚性横隔板弧形切口的最佳孔型;适当增加孔型4的切口半径和横隔板厚度有利于提高其疲劳寿命,增加切口半径较增加板厚效果更好。The fatigue cracks at the arc-shape cutouts in the diaphragm of the steel box girder are one of the major fatigue deteriorations of the girder.To improve the fatigue performance of the structural details and determine the optimal structures of the cutouts,a suspension bridge（the stiffening girder of the bridge being the steel box girder）was taken as the research object,the finite element model for the segment of the steel box girder was established and the fatigue stress analysis was carried out.Based on the Palmgren-Miner linear accumulated damage rule and the S^Ncurves as provided in the Eurocode 3,the fatigue lives of the cutouts were calculated,the fatigue performance of the 6 kinds of the common arc-shape cutouts at home and abroad was compared and the influences of the cutout radii and diaphragm thickness on the fatigue stresses were analyzed.The results demonstrate that under the action of the wheel loads,the obvious tensile and compressive stress concentration zones exist at the arc-shape cutouts in the diaphragm.The fatigue cracks initiate from the compressive stress concentration zone and the direction of the crack propagation is basically perpendicular to that of the principal compressive stress.The shapes of the cutouts have significant influences on the fatigue performance of the cutouts.Among the typical shapes of the cutouts commonly used at home and abroad,the round arc＋straight line cutout（cutout 4）is the best shape of the cutout for the rigid diaphragm.The appropriate increase of the radius of the cutout 4 and the diaphragm thickness is helpful to the improvement of the fatigue life of the cutout and the effect of increase of the cutout radius is better than that of increase of the diaphragm thickness.

关 键 词：钢箱梁 横隔板 弧形切口 疲劳性能 构造优化 疲劳裂纹 有限元法 

分 类 号：U441.4[建筑科学—桥梁与隧道工程] U443.35[交通运输工程—道路与铁道工程]