站台雨棚钢结构在锈蚀作用下的耐久性评估

Durability evaluation of steel structure of platform canopy under corrosion

考虑钢构件由锈蚀引起的几何削弱及材性退化,提出一种钢结构在锈蚀作用下的耐久性评估方法。通过引入大气腐蚀模型,采用锈蚀缺陷分析方法建立结构有限元模型,同时给出锈蚀钢材屈服应力比下降标准曲线得到结构剩余承载力准则。基于该评估方法,通过迭代计算构件的临界失重率,进而确定构件的损伤系数(耐久性指标)。结合算例阐述站台雨棚钢结构在大气均匀锈蚀作用下的耐久性评估流程。研究结果表明:站台雨棚整体结构的损伤系数随服役时间近似呈线性增长;均匀锈蚀引起的几何削弱与材性退化对结构整体的损伤系数几乎相同;该分析流程可为高铁站台雨棚在大气锈蚀作用下的耐久性评估提供参考。

A new evaluation method was proposed for the durability of corrosion steel structures considering the geometric weakening and material degradation impacts. A finite element model was also established by employing rust defect analysis. The standard curve of the residual bearing capacity of the structure was obtained by the yield curve of the rusted steel. Based on the evaluation method, the critical weight loss rate of the member was calculated iteratively. Thereby the damage coefficient(durability index) of the member was determined. Finally, a numerical case was given to illustrate the procedure of durability assessment. The steel structure of the platform canopy under uniform atmospheric corrosion was also provided. The results show that the damage coefficient of the overall structure of the platform canopy increases linearly with the service time. It can be also found that the damage coefficients of geometric weakening and material degradation caused by uniform corrosion on the whole structure are almost the same. The analysis process can provide a reference for the durability evaluation of the high-speed rail platform canopy under atmospheric corrosion.