钢筋锈蚀对钢筋混凝土结构固有频率和阻尼比影响的试验研究

针对钢筋锈蚀使钢筋混凝土结构的抗震性能和耐久性能退化，并且对结构动力特性产生影响的现象，采用电化学加速锈蚀方法，通过法拉第定律控制锈蚀程度，将钢筋的理论锈蚀率分为5%，10%，15%三个锈蚀阶段，在实验室中模拟了钢筋混凝土梁中钢筋的锈蚀过程。根据悬臂梁的自由振动衰减特性，采用自由衰减法采集了钢筋混凝土梁的固有频率和阻尼比，研究了钢筋锈蚀对钢筋混凝土梁固有频率和阻尼比的影响。结果表明:钢筋锈蚀对钢筋混凝土梁的固有频率和阻尼比有显著影响，钢筋混凝土梁的固有频率随着钢筋锈蚀程度的加深而呈减小趋势，阻尼比随着钢筋锈蚀程度的加深而呈增大趋势，因此阻尼比可以作为损伤指标用于混凝土结构腐蚀损伤检测。

Experimental Study on Effect of Reinforcement Corrosion on Natural Frequency and Damping Ratio of Reinforced Concrete Structures

In view of reinforcement corrosion degrading earthquake-resistance performance and durability of reinforced concrete structures and effecting their dynamic properties as well, natural corrosion process of reinforcement was simulated in the laboratory using accelerated electrochemical corrosion technique and controlling corrosion degree with Faraday’s Law, and the theoretical corrosion degree of steel is divided into three stages: 5%, 10% and 15%. The effects of reinforcement corrosion on natural frequency and damping ratio of reinforced concrete structures were examined by means of free vibration attenuation characteristics of cantilever beams and the free attenuation method. The results show that reinforcement corrosion has great effects on natural frequency and damping ratio of reinforced concrete beam, the damping ratio increases with the corrosion level while natural frequency decreases. The damping ratio can be used as the damage index for the concrete structure corrosion damage detection.