局部腐蚀对钢筋混凝土墩柱力学性能退化影响数值模拟

Finite element analysis of mechanical behaviors degradation of partially corroded reinforced concrete piers

为了探究局部腐蚀对钢筋混凝土(RC)墩柱的力学性能退化规律,本研究建立了局部腐蚀RC墩柱有限元模型,探讨不同目标腐蚀率下墩柱的力学性能退化规律,并与相关试验结果进行对比分析。考虑到箍筋腐蚀较主筋腐蚀严重的现象,共设计6个不同目标腐蚀率工况;有限元模型考虑了保护层混凝土锈胀开裂导致其强度折减影响,对腐蚀区域钢筋强度按质量损失率进行了折减,同时引入四节点粘结滑移单元考虑锈蚀钢筋与混凝土之间的粘结性能退化影响。研究结果表明:本有限元模型可较准确模拟腐蚀对墩柱力学性能的影响,数值模拟结果与试验实测关于轴心受压柱的承载力最大相对误差为7.87%;RC墩柱承载力随局部钢筋腐蚀程度增加呈退化趋势,当主筋锈蚀率达20%时,RC墩柱轴压承载力和侧向承载力分别降低30.73%和5.87%。

A finite element model of partially corroded Reinforced Concrete(RC)pier was developed and validated by the test results to investigate mechanical behaviors of partially corroded RC pier.Six target corrosion levels were applied to rebars and stirrups,the stirrups corrosion ratio was higher than that of rebar as stirrup corrosion was always more serious than rebar corrosion in field observation.The strength degradation of steel bars and concrete cover in the corrosion area were considered according to the mass loss and corrosion-induced cracking,respectively.Four-node bond-slip element was developed to simulate the bond degradation between corroded rebar and concrete.The results show that the numerical simulation can reproduce the effects of corrosion on bearing capacity of the RC pier well,the maximum bearing capacity difference between the test and simulation was 7.87%,the axial bearing capacity and lateral bearing capacity of the pier model decrease by 30.73%and 5.87%for model at 20%rebar mass loss respectively.