锈蚀钢筋混凝土桥梁结构地震易损性分析

为了研究锈蚀钢筋混凝土桥梁结构的地震易损性问题,以一个简化的单墩体系为例,通过修正材料的单轴本构关系,建立了考虑钢筋锈蚀损伤的桥梁结构非线性分析模型.考虑地震动的不确定性,根据场地类型选取50条地震波,通过弹塑性动力时程分析获得结构的地震响应,针对不同的钢筋锈蚀率,建立地震需求参数与地震动参数之间的关系,分别定义墩柱的4个损伤指标,形成不同钢筋锈蚀率的桥梁结构易损性曲线.通过结果对比分析发现:钢筋混凝土桥梁结构的地震易损性随着钢筋锈蚀率的增大而增大;当钢筋锈蚀率在10%~15%时,钢筋混凝土桥梁结构的地震易损性基本不变.

Seismic Fragility Estimation of Corroded Reinforced Concrete Girder Bridges

To investigate corrosion effects on the seismic fragility,a simplified single-pier was analyzed,and the corrosion damage model was built through the modification of materials' stress-strain relationship.Considering the randomness of input ground motions and the influence of site-type,the relationship between the seismic demand parameters and the ground motion intensity indicators was obtained by nonlinear dynamic time history analysis. After four damage indicators about bridge column are defined,the seismic fragility curves of bridges in different corrosion levels were presented. Results show that bridges' seismic fragilities increase with the corrosion levels; this increasement is insignificant in the range of corrosion rate 10% ~ 15%.