溶蚀和氯盐侵蚀条件下钢筋混凝土柱抗震性能退化过程的数值模拟

Numerical simulation on deterioration of seismic performance of reinforced concrete column in the process of leaching and chloride attack

针对溶蚀和氯盐侵蚀条件下钢筋混凝土柱抗震性能的退化问题,首先,利用Fick定律和质量守恒定律,建立了水环境下混凝土柱中钙离子和氯离子的耦合传输模型;其次,基于钙溶蚀引起的混凝土损伤特征和氯盐侵蚀导致的钢筋锈蚀特点,建立了溶蚀混凝土和锈蚀钢筋的损伤本构模型;最后,利用TCL语言编制了相关模型的计算程序,并通过Open Sees进行混有限元模拟,分析了钙溶蚀和氯盐侵蚀共同作用下混凝土柱抗震性能的时变规律。结果表明,随着服役时间的增加,柱的受压、受弯承载力及延性逐渐退化,滞回耗能能力也不断降低;轴向力的提高能够引起混凝土柱受弯承载力的增加,但在服役后期,轴向力的影响不够明显;整个服役过程中,提高混凝土柱的轴向力,可导致其弹塑性变形能力下降,引起柱的延性和滞回耗能能力降低。

This paper numerically investigates the deterioration of seismic performance of reinforced concrete column in the process of leaching and chloride attack.Firstly,Fick’s law and mass conservation law are used to establish a coupled diffusion model of calcium and chloride ions in saturated concrete;Secondly,based on the characteristics of concrete damage caused by calcium leaching and steel corrosion induced by chloride attack,the damaged constitutive models of leached concrete and corroded steel are supposed;Finally,these models are programmed by using TCL language,and they mix with Open Sees for a finite element analysis on the time-varying seismic performance of concrete column,which is subjected to the coupled calcium leaching and chloride attack.The results show that:with the increase of in-serviced time,the compressive and flexural capacities as well as ductility of the column have gradual reduction,while its hysteretic energy also decreases;the flexural capacity of the column firstly increases with its axial force,but there is basically no obvious effect of axial force on its flexural capacity;The elastoplastic deformation,ductility and hysteresis energy of the column decrease with the increase in the axial force.