大气环境腐蚀下钢结构力学性能研究综述

Review of Research on Mechanical Properties of Steel Structure Under Atmospheric Environment Corrosion

钢结构因质轻、强度高、建造方便、塑性及抗震性能好等优点越来越受到青睐。近几十年来,随着国内钢材产量及品种大幅提升,钢结构应用范围也越来越广,除传统的钢结构厂房外,钢结构也逐渐应用于高层、超高层及大跨度结构中。然而,钢结构有一个明显的缺点,即易腐蚀,暴露在大气环境中的钢结构,钢材表面会形成一种薄液膜,在干湿交替过程中对结构产生腐蚀。随着我国现代工业化进程的加快,环境问题日益突出,其中在富含SO 2的酸性大气环境和富含Cl-的近海大气环境下钢材的腐蚀最为严重。钢材腐蚀不仅会造成巨大的经济损失,还会影响结构的安全稳定。钢材遭受腐蚀后,构件有效截面面积减小,强度和延性下降,不均匀腐蚀引起的锈坑会导致应力集中等,在动力荷载作用下,这些现象将引起钢材脆性断裂并影响疲劳强度,增加了钢结构风险事故发生的概率。大气环境腐蚀下钢结构性能的劣化已引起众多学者的关注。目前,国内外学者对钢材大气腐蚀的研究主要集中于:(1)钢材的大气腐蚀机理及影响因素;(2)不同大气腐蚀试验方法及其相关性;(3)钢材的大气腐蚀深度预测模型,目前虽已建立多种腐蚀深度预测模型,但要建立一种形式相对简单且精度高的预测模型仍需深入探讨;(4)大气腐蚀下钢材、钢构件的力学性能;(5)大气腐蚀下钢结构动态力学性能,此方面研究相对较少,目前国内外仍缺乏系统的报道。因此,为了明确大气环境(酸性和近海大气环境)腐蚀对钢结构性能的影响,本文对近50年国内外有关钢结构大气腐蚀的研究报道进行了评述,重点讨论了酸性、近海两种大气环境下,腐蚀对钢结构静态和动态力学性能的影响。首先分别详述了钢材在酸性(富含SO 2)、近海(富含Cl-)大气环境下的腐蚀机理,以及大气腐蚀的影响因素;其次总结了钢材大气腐蚀试验方法,大气腐蚀下钢结构力学性能的相关研究;最后讨论了当前有关钢结构大气腐蚀研究的一些重要问题,并展望了今后的研究方向。

Steel structureshave been widely applied because of its light weight,high strength,convenient construction,good plasticity and seismic performance.In recent decades,with the sharp increase in domestic steel production and variety,steel structures have not only been applied to traditional industrial plants,but also gradually applied to high-rise,super high-rise and long-span structures.However,steel structure has an obvious disadvantage,that is,it is easy to corrode,and the steel structures exposed to the atmospheric environment will form a thin liquid film on the surface of the steel,which will corrode the structure during the alternating wet and dry process.With the acceleration of modern industrialization in China,environmental problems have become increasingly prominent,and steel corrosion is most severe in acidic atmospheres rich in SO 2 and in offshore atmospheres rich in Cl-.Corrosion of steel not only causes huge economic losses,but also affects the safety and stability of the structures.Because of corrosion,the effective cross-sectional areas of the components decrease,the strength and ductility decrease,and the rust pits generated by the uneven corrosion will cause stress concentration,etc.When the dynamic load acts,these phenomena will cause brittle fracture of the steel and affect the fatigue strength,increasing the probability of steel structure risk.The deterioration of steel structures performance under atmospheric environmental corrosion has attractedwide attention.At present,researches on atmospheric corrosion of steels by scholars at home and abroad mainly focus on:I.atmospheric corrosion mechanism and influencing factors of steels,Ⅱ.different atmospheric corrosion test methods and their correlation,Ⅲ.research on atmospheric corrosion depth prediction model of steels(Although a variety of models have been established at present,it is necessary to study a predictive model with relatively simple expression and high precision),Ⅳ.mechanical properties of steel and steel components under atmospheric corrosion,Ⅴ.the dynamic mechanical properties of steel structures under atmospheric corrosion(It still lack intensive study about this aspect).Accordingly,in order to clarify the influence of atmospheric environment(acid and offshore atmospheric environment)corrosion on the steel structure performance,this article reviews the worldwide researches about atmospheric corrosion of steel structures in recent 50 years,and focuses on the effects of corrosion on the static and dynamic mechanical properties of steel structures under acidic and offshore atmospheric conditions.Firstly,the corrosion mechanism of steel in acidic(rich in SO 2)and offshore(rich in Cl-)atmospheres and the influencing factors of atmospheric corrosion are described in detail.Secondly,the atmospheric corrosion test methods of steel and the related research work on the mechanical properties of steel structures under atmospheric corrosion are summarized.Finally,some important issues concerning the research of atmospheric corrosion of steel structures are discussed,and some suggestions for further research are proposed.