氯盐侵蚀下桥梁地震易损性研究进展

Research progress on bridge seismic vulnerability analysis under chloride attack

氯盐侵蚀引起的钢筋锈蚀和混凝土保护层开裂,会导致结构在地震作用下的抗震性能劣化.综述了国内外桥梁结构地震易损性分析的研究进展,从氯离子的侵蚀过程、钢筋和混凝土的力学性能劣化、钢筋与混凝土之间的黏结性能弱化三方面进行了归纳总结,揭示考虑氯离子侵蚀的桥梁地震易损性分析,除进行传统的地震概率需求和能力分析外,需着重考虑氯离子的侵蚀效应对结构抗震性能的影响.并针对当前研究中存在的问题提出了一些建议.指出现有研究基于氯离子侵蚀得到的钢筋锈蚀速率模型、黏结本构模型尚不统一,很有必要开展更深的研究;自然环境下的氯盐侵蚀更倾向于坑蚀,非均匀锈蚀下的桥梁地震易损性分析有待进一步开展。

The chloride-induced steel corrosion and concrete cover cracking lead to the deterioration of structural seismic performance.The research progress of seismic vulnerability analysis of bridge structures at home and abroad was summarized from three aspects,including chloride diffusion process,the deterioration of mechanical properties of steel and concrete,and the weakening of bond properties between reinforcing steel and concrete.It is indicated that when conducting bridge seismic vulnerability analysis under chloride attack,in addition to the traditional seismic probability demand and capacity analysis,the seismic performance degradation effect resulting from chloride transport mechanism into concrete should be taken into account.Some suggestions were put forward in view of the problems existing in the current research.Further research should be carried out on the corrosion rate and bond constitutive models.The chloride-induced steel corrosion under marine environment is more prone to pitting corrosion,thus seismic vulnerability analysis under non-uniform corrosion needs to be further developed.