聚氯乙烯-碳纤维增强复合材料管混凝土柱-钢筋混凝土环梁T型节点低周反复荷载试验与恢复力特性数值模拟研究

Quasi-Static Loading Tests and Numerical Simulations of Restoring Force Characteristics of T-Joints Between PCCC Columns and RC Ring Beams

为研究聚氯乙烯-碳纤维增强复合材料(PVC-CFRP)管混凝土柱-钢筋混凝土(RC)环梁T型节点的恢复力特性,完成了11根试件的低周反复荷载试验。试验结果表明:增大的环梁节点能有效实现PVC-CFRP管混凝土柱与RC梁的连接,试件显示出良好的抗震性能。在此基础上,优选材料本构关系,采用纤维模型法,编制非线性分析程序,开展节点拟静力试验数值模拟研究,模型预测结果与试验结果吻合较好。基于验证的数值模型,延拓分析环梁节点混凝土强度、环梁高度、梁纵筋配筋率、柱直径以及纵筋屈服强度等参数对其骨架曲线的影响规律,并提出合理设计建议。数值模拟结果表明:环梁节点核心区混凝土强度由20 MPa增至60 MPa,试件的峰值弯矩提高13.7%,极限位移降低8.0%;梁纵筋配筋率由2%增至5%,试件的峰值弯矩提高26.3%,极限位移降低19.9%;梁纵筋屈服强度由400 MPa增至600 MPa,试件的峰值弯矩提高56.3%,极限曲率降低17.9%;试件环梁高度由350 mm增至450 mm,试件的峰值弯矩影响不明显,而极限位移降低11.0%;柱直径由200 mm增至300 mm,试件的峰值荷载提高56.3%,极限位移增加28.5%。

To investigate the restoring force characteristics of T-joints between PVC-CFRP confined concrete columns and RC ring beams,eleven exterior joint specimens under quasi-static loading were tested.The experimental results showed that the enlarged ring beam joints could effectively connect the PVC-CFRP confined concrete columns and RC beams,and the joint specimens showed favorable seismic performance.On the basis of the experimental study,the material constitutive relations were reasonably selected,the fiber model method was adopted,the nonlinear analysis program was compiled,and the quasi-static tests of the exterior joint specimens were simulated numerically.The model predicted results agreed well with the experimental data.Based on the numerical model verified by experiments,the effects of concrete strength,height of ring beam,longitudinal reinforcement ratio of beam,column diameter and yield strength of longitudinal reinforcement on skeleton curves were analyzed,and reasonable design suggestions were proposed.The numerical simulation results showed that when the concrete strength of the ring beam joint increased from 20 MPa to 60 MPa,the peak bending moment increased by 13.7%,while the ultimate displacement decreased by 8.0%.As the longitudinal reinforcement ratio of beam increased from 2%to 5%,the peak bending moment increased by 26.3%,while the ultimate displacement decreased by 19.9%.As the yield strength of beam longitudinal reinforcement increased from 400 MPa to 600 MPa,the peak bending moment increased by 56.3%,while the ultimate curvature decreased by 17.9%.When the height of ring beam increased from 350 mm to 450 mm,the peak bending moment showed little influence,while the ultimate displacement decreased by 11.0%.When the column diameter increased from 200 mm to 300 mm,the peak load increased by 56.3%,and the ultimate displacement increased by 28.5%.