江阴长江大桥疲劳应力特征的研究

Study on fatigue stress feature of Jiangyin Yangtze River Bridge

对江阴大桥钢箱梁顶板与U肋连接部位和横隔板弧形缺口部位4个构造细节疲劳应力特征进行了对比分析。根据江阴大桥裂纹检测统计结果,针对4个构造细节进行应变监测,基于各构造细节的应变时程,分析了不同构造细节疲劳应力特征。对比研究纵桥向1/4跨径截面和1/8跨径截面以及横桥向下游慢车道、下游快车道和上游慢车道的疲劳应力特征,评估不同位置疲劳损伤大小和可靠度指标,判定最易出现的疲劳损伤部位。研究结果表明:顶板构造细节为最易产生的疲劳损伤部位;1/4跨径截面的疲劳应力特征与1/8跨径截面的相似;下游慢车道的疲劳损伤最大,对应的疲劳寿命为23a;下游快车道的疲劳损伤大于上游慢车道的疲劳损伤,对应的疲劳寿命分别为55a和82a。

Analysis on the fatigue stress feature of the trough-deck and diaphragm are gap positions of Jiangyin Yangtze River Bridge.Strain sensors were set at the four structure details based on the survey of fatigue crack locations of Jiangyin Yangtze River Bridge to monitor the strain, and the fatigue stress feature of four structure details was analyzed according to the data of fatigue stress spectrum. The fatigue stress feature of 1/4 and 1/8 cross section was comparatively studied with the feature of roof detail. The heavy traffic lane and light lane on downstream and the heavy traffic lane on upstream were also comparatively studied to assess the fatigue damage degree and reliability index,the most typical fatigue position was determined.The results show that the roof detail was the most typical fatigue position of the four details.The fatigue stress feature of 1/4 and 1/8 cross section was similar.The damage degree of heavy traffic lane on downstream was the largest when the fatigue life of roof detail was 23 years.The damage degree of the light lane on downstream lane was more than that of upstream lane,and the respective fatigue life of roof detail on each lanes were 55 years and 82 years.