榫式连接拼装RC柱轴压性能数值分析

Numerical analysis on axial compression behavior of tenon connection for prefabricated RC columns

利用ABAQUS有限元软件对轴压荷载作用下榫式连接拼装RC柱进行非线性有限元模拟,并进行试验验证。利用验证的有限元模型研究不同上柱段榫柱宽度及锥形界面倾角的拼装RC柱轴压性能,分析拼装RC柱的荷载-变形关系、荷载-应变关系、不同部件的内力分配、界面接触应力和轴压承载力,研究上柱段榫柱宽度及锥形界面倾角对其受力性能的影响。研究结果表明:上柱段锥形界面中越靠近根部,其接触应力越大,上柱段榫柱侧面的接触应力接近于0 MN,锥形界面的接触应力随倾角增大而减小;在峰值荷载时,各部件共同提供轴压承载力;超过拼装RC柱的轴压承载力主要由榫柱混凝土与纵筋承担,后浇段混凝土承担的轴压承载力迅速降低;在其他参数不变的情况下,拼装RC柱轴压承载力随上柱段榫柱宽度增大近似呈线性增大;当上柱段锥形界面倾角小于30°时,倾角对拼装RC柱后浇段纵筋的应变发展和轴压承载力的影响较小,同一横截面上纵筋的应变发展协调;当上柱段锥形界面倾角大于30°时,拼装RC柱轴压承载力随倾角增大近似呈线性减小,榫柱纵筋与后浇段纵筋的应变发展差异增大;根据有限元和理论分析结果得出拼装RC柱的轴压承载力公式,计算结果与有限元结果吻合较好。

By using ABAQUS,nonlinear finite element numerical simulation of tenon connection for prefabricated RC columns was carried out.The verified finite element model was used to study the axial performance of prefabricated RC columns with tenon of different widths and taper area of different angles.Based on the computed results,load-deformation relationship,internal force distribution,contact stress and axial bearing capacity of the model were analysed,and the influence of the width of the tenon and the angle of the taper area on the mechanical performance of prefabricated RC columns was investigated.The results show that the closer to the root in the tenon side of the upper column,the greater the contact stress.The contact stress of the tenon side of the upper column is close to 0 MN.The contact stress of the taper area decreases with the increase of the inclination angle.When the peak load is applied,all components together provide the axial bearing capacity of axial compression.Exceeding the peak load,the axial bearing capacity of prefabricated RC columns is mainly provided by the tenon’s concrete and the longitudinal reinforcement,and the axial bearing capacity of the post-pouring’s concrete decreases rapidly.When the other parameters are fixed,the axial bearing capacity of the prefabricated RC column almost increases linearly with the increase of the width of the tenon.When the angle of the taper area is smaller than 30°,the influence of the angle of the taper area is unobvious,and the strain development of the longitudinal reinforcement on the same cross section is coordinate.When the angle of the taper area exceeds 30°,the axial bearing capacity of the prefabricated RC column almost decreases linearly with the increase of the width of the tenon.The difference of strain development between tenon’s longitudinal bar and post-pouring’s longitudinal bar increases.A design equation to calculate the axial compressive strength of prefabricated RC columns is proposed and the calculated results show good agreement with FEA results.