基于DM-LEFM理论的混凝土桥梁受力主筋疲劳全寿命分析  

Life-cycle fatigue analysis of main reinforcements of the concrete bridge based on the DM-LEFM theory

作　　者：王剑[1] 文国华[1] WANG Jian;WEN Guohua(College of Civil Engineering,Hunan City University,Yiyang 413000,China)

机构地区：[1]湖南城市学院土木工程学院,湖南益阳413000

出　　处：《铁道科学与工程学报》2020年第10期2597-2602,共6页Journal of Railway Science and Engineering

基　　金：湖南省教育厅科研资助项目(15C0256)。

摘　　要：混凝土桥梁主筋疲劳全寿命包含裂纹形成寿命和裂纹扩展寿命。鉴于线弹性断裂力学无法估算裂纹形成寿命,提出基于DM-LEFM理论的桥梁主筋疲劳全寿命估算方法。通过损伤力学(DM)估算疲劳裂纹的形成寿命,线弹性断裂力学(LEFM)估算疲劳裂纹的扩展寿命,桥梁的疲劳全寿命即为两者之和。结合龙河特大桥工程,分析估算桥梁受拉主筋的疲劳全寿命。研究结果表明:龙河特大桥疲劳裂纹形成寿命为2.102×105 d,大于疲劳裂纹扩展寿命1.041×105 d,桥梁疲劳全寿命合计3.143×105 d,约861 a。由于损伤力学理论的限制,计算结果未考虑腐蚀对疲劳全寿命的影响,需进一步研究腐蚀对钢筋力学参数的影响。基于DM-LEFM理论的桥梁疲劳全寿命为桥梁疲劳安全评价提供了技术支持。Life-cycle fatigue development of main reinforcements of the concrete bridge includes crack initiation and crack propagation.Since the linear elastic fracture mechanics is incapable of estimating crack formation life,the DM-LEFM theory was proposed to calculate the fatigue life for the concrete bridge.The damage mechanics(DM)was applied to deal with the crack initiation life,while the linear elastic fracture mechanics(LEFM)was used for the estimation of crack propagation life.In combination with the engineering project of the Long River Bridge,the life-cycle fatigue analysis of the main reinforcements was performed.Results show that the crack initiation life for the Long River Bridge is 2.102×105 days,and the crack propagation life is 1.041×105 days,thus the fatigue life should be 3.143×105 days,about 861 years.Due to the limitation of damage mechanics,the results are unable to take corrosion into consideration,thus further study should be carried out to analyze the impact that corrosion has on mechanical parameters of steel components.The idea of life-cycle fatigue analysis based on the DM-LEFM theory could provide technical support to the safety evaluation for concrete bridges.

关 键 词：损伤力学 线弹性断裂力学 疲劳全寿命 混凝土桥梁 

分 类 号：TU448.13[建筑科学—岩土工程]