耐久性损伤耦合效应对钢筋混凝土框架节点抗震性能研究

Study on Impact of Coupling Effect of Durable Damages on Seismic Behavior of Joints in Reinforced Concrete Frame Structures

目的研究耐久性损伤耦合效应对钢筋混凝土结构框架节点的抗震性能的影响.方法考虑非线性粘结滑移,利用ABAQUS有限元分析软件建立钢筋混凝土梁柱节点非线性模型,分析混凝土保护层碳化、梁纵筋锈蚀、冻融循环三者的耦合效应对钢筋混凝土梁柱节点抗震性能的影响.结果在三种损伤因素共同作用下,当钢筋的锈蚀率从5%增加到10%时,试件的累积耗能能力和极限位移全部发生急剧衰减,试件的抗震性能严重退化;在碳化、冻融及钢筋锈蚀率为10%的情况下,滞回曲线出现弓形,试件的承载力及延性均急剧下降;随着混凝土的碳化,试件承载力提高的同时延性在逐渐降低.结论无论钢筋锈蚀率、混凝土保护层的碳化或冻融循环次数,其中任何一种损伤量的增加,均会导致试件抗震能力的下降;而当三者同时作用时,对边节点的抗震性能影响最为严重.

This paper studied the impact of coupling effect of the durable damages of reinforced concrete structure on seismic performance. Considering the nonlinear bond-slip, the nonlinear finite elements models of the joints of the beams and columns in the reinforced concrete structure were founded by the ABAQUS package. Through the analysis ,the impacts of the carbonation of the concrete protective layer, the corrosion of the longitudinal bar in the beam and the coupling effect of the freezing and thawing cycle on the seismic behavior of the joints of the beam and column in the reinforced concrete structure can be investigated. The result shows that under the three factors take effect at the same time ,when the steel bar corrosion rate increased from 5% to 10% ,the specimen of accumulated energy dissipation capacity and limit displacement attenuation, took place in the degeneration of seismic performance. When the condition of the rebar corrosion rate is 10%, the hysteresis curve appeared bow-shaped, the bearing capacity and ductility of the specimen are falling sharply. As the concrete carbonation, specimen to improve bearing capacity and ductility is gradually reduced. Conclusion is that the increase of any factor can result in the rapid decreasing in the seismic performance of the specimen. Under the three factors take effect at the same time, the worst influence on exterior joint seismic performance.