免涂装耐候钢的腐蚀模型及其桥梁强度和稳定设计方法研究

Research on Corrosion Model of Uncoated Weathering Steel and Its Strength and Stabilization Design Method for Bridges

免涂装耐候钢桥面临着腐蚀环境的巨大挑战,基于ISO规范对环境腐蚀的分类,回顾和讨论金属材料和耐候钢腐蚀评价方法。依据我国《桥梁用结构钢》和《耐候结构钢》的规定,采用指数线性模型得到《桥梁用结构钢》规定耐候钢腐蚀上限模型。对比结果表明,我国耐候钢具有较好的抗腐蚀性能,并且在各环境腐蚀等级中,抗腐蚀性能与欧洲耐候钢基本相当。通过耐候钢腐蚀试验数据验证了腐蚀模型的准确性,表明基于耐候钢腐蚀上限模型可作为免涂装耐候钢桥梁的设计依据。结合《铁路桥梁钢结构设计规范》与《公路钢结构桥梁设计规范》,提出基于腐蚀量模型的免涂装耐候钢桥梁强度和稳定设计方法,为我国免涂装耐候钢桥梁设计提供理论依据。为简化设计,还提出容许腐蚀厚度设计方法用于C1~C3腐蚀环境,其中,C1和C2腐蚀环境容许腐蚀厚度取500μm,C3腐蚀环境容许腐蚀厚度取1000μm。

Corrosion environment is a great challenge to uncoated weathering steel bridges(UWSB).Based on the environment corrosion category according to ISO standard,the corrosion evaluation methods of materials and weathering steel are retrospected and discussed.According to Chinese Structural Steel for Bridge and Atmospheric Corrosion Resisting Structural Steel,the upper corrosion limit model of weathering steel specified by Structural Steel for Bridge is analyzed and obtained with power-linear model.The comparison result indicates that the corrosion resistance of Chinese weathering steel is equal to that of European weathering steel.Meanwhile,the analysis of weathering steel corrosion tests data validated the accuracy of corrosion model and the upper corrosion limit model can provide a theory basis to design UWSB.Moreover,combined with Code for Design of Steel Structure of Railway Bridge and Specifications for Design of Highway Steel Bridge,this paper proposes a strength and stabilization design method for UWSB and provides a theoretical foundation for the design of UWSB in China.To simplify the design,the allowance corrosion loss design method is also put forward for C1~C3 environment.Typically,the allowance corrosion loss for C1 and C2 environment is 500μm,while the allowance corrosion loss for C3 environment is 1000μm.