箍筋锈蚀钢筋混凝土柱受火后抗震性能试验研究及有限元分析

为研究箍筋锈蚀钢筋混凝土柱的火灾反应及其火灾后的抗震性能，设计并制作4根尺寸及配筋相同的钢筋混凝土柱，以锈胀裂缝为损伤指标，对混凝土柱的箍筋进行电化学加速锈蚀试验，得到箍筋不同锈蚀率的混凝土柱。对RC柱进行限时受火试验，研究箍筋不同锈蚀率的混凝土柱的高温反应。对历经高温的钢筋混凝土柱进行低周水平反复荷载试验，并利用ANSYS进行有限元分析，探究受火后锈蚀钢筋混凝土柱抗震性能变化规律，分析建模方法的可靠性。研究表明：箍筋锈蚀将导致钢筋混凝土柱截面温度场畸变；锈蚀箍筋对受火后钢筋混凝土柱抗震性能影响显著，锈蚀率越高，耗能能力越低，刚度和延性退化越严重；有限元分析与试验结果吻合较好，模拟方法可行；提出了高温后箍筋锈蚀钢筋混凝土柱受剪承载力计算式，可供箍筋锈蚀火灾后钢筋混凝土柱安全性鉴定参考。

Experimental research and finite element analysis on seismic performance of reinforced concrete columns with corroded stirrups after fire

In order to study the fire response of corroded reinforced concrete columns and the seismic performance after fire, four reinforced concrete columns with the same size and reinforcement were designed. Firstly, taking corrosion-induced expansion crack as damage index, the electrochemical accelerated corrosion test was carried out on stirrups of reinforced concrete columns, thereby reinforced concrete columns with different corrosion rates of stirrups were obtained. Then a time-limited fire test was carried out to study the fire response of reinforced concrete columns with different corrosion rates. Finally, low-cycle reversed loading test was carried out on the reinforced concrete columns after fire. ANSYS was used for numerical simulation analysis to explore the change rule of seismic performance of corroded reinforced concrete columns after fire and analyse the reliability of numerical simulation analysis method. The results show that the corrosion of stirrups leads to the distortion of temperature field of reinforced concrete columns section. The corroded stirrups have a significant impact on the seismic performance of reinforced concrete columns after fire. The higher the corrosion rate, the lower the energy dissipation capacity of the components, and the more serious the stiffness and ductility degradation. The numerical analysis results agree well with the experimental results, and the numerical analysis method is feasible. The calculation formula of shear capacity of reinforced concrete column after stirrup corrosion and fire is put forward, which can be used for safety evaluation of reinforced concrete columns after stirrup corrosion and fire.