考虑轮迹横向分布的钢箱梁桥面板U肋处受力与疲劳分析

Stress and fatigue analysis of U-ribs of steel box girder bridge deckconsidering wheel track lateral distribution

为研究轮迹横向分布对钢桥面板受力与疲劳性能的影响,本研究基于有限元理论建立悬索桥钢桥面板有限元模型,得到不同轮载作用下、不同参数构造的钢桥面板细节的等效应力,并计算其疲劳损伤度;通过数学方法建立车辆轮迹分布模型,确定轮迹在车道不同位置的分布概率,从而提出一种考虑轮迹横向分布的疲劳损伤计算方法。结果表明:U肋与横隔板连接处的应力幅受轮迹横向分布的影响范围较小,约为1.5 m,不必考虑多车效应;U肋与横隔板厚度的增加能改善研究部位的受力性能;U肋腹板处的损伤相对较小,靠近顶板部位、腹板与底板连接部位的损伤较为严重;考虑车辆轮迹分布后的疲劳损伤度下降了74%,因此考虑车辆轮迹的位置可以提高疲劳损伤评估的精确度。

In order to study the influence of lateral distribution of wheel tracks on the stress and fatigue performance of steel bridge decks,based on the finite element theory,a finite element model of steel bridge decks for suspension bridges was established,the equivalent stress of steel bridge decks with different parameters under different wheel loads was obtained at detail,and the fatigue damage degree was calculated.A vehicle wheel track distribution model was established mathematically,the distribution probability of wheel tracks at different position in the lane was determined,and a method for calculating fatigue damage considering the lateral distribution of wheel tracks was proposed.The results show that the stress amplitude at the joint between the U-rib and the diaphragm is less affected by the lateral distribution of wheel tracks,which is about 1.5 m,and it is not necessary to consider the multi-vehicle effect.The thickness increasing of U-ribs and diaphragms can improve the stress performance.The damage at the U-rib web is relatively less,but the damage near the top plate and the connection between the web and the bottom plate is more serious.The fatigue damage after considering the vehicle wheel track distribution has been decreased by 74%,so considering the position of wheel tracks can improve the accuracy of fatigue damage assessment.