钢环加固圆钢管混凝土柱-RC梁角节点轴压性能有限元分析

针对圆钢管混凝土柱-RC梁角节点，提出了对角节点的节点区采用多段钢环加固的构造方案，并对加固节点模型的轴压性能开展有限元分析研究。通过已有研究成果验证了有限元模型分析方法的可靠性，继而采用ABAQUS有限元分析软件建立152个加固节点模型进行轴压试验模拟。有限元分析结果表明，以多段钢环加强的圆钢管钢筋混凝土柱-RC梁角节点轴压性能优于普通节点，加固节点具有更高的轴压承载力和更好的延性，加固效果明显。参数分析表明：加固角节点的轴压承载力随节点混凝土轴心抗压强度、节点区钢环体积占比和节点区纵筋配筋率的增加而增加；角节点的轴压承载力受梁端剪力影响，较大的梁端剪力可能造成节点延性降低。根据分析结果，建立了节点区采用钢环加固的圆钢管约束混凝土柱-RC梁角节点的轴压承载力算式，供设计该类节点参考。

Finite element analysis on axial compressive behavior of steel-tube confined reinforced concrete column-reinforced concrete beam knee joint stiffened with steel rings

A new construction method that strengthens circular steel-tube confined reinforced concrete (RC) column-RC beam knee joint with additional steel rings in the joint area is proposed. A total of 152 finite element (FE) models of circular steel-tube confined RC column-RC beam knee joint stiffened with steel rings in the joint area were established using the ABAQUS software to study the axial compressive behavior of the stiffened joints, after the FE method was validated using results from existing studies. The FE results show that the stiffened joint has a better axial compressive behavior than common joints, due to its higher bearing capacity and better ductility, which proves the effectiveness of the new strengthening method. Based on the parameter analysis results, it is concluded that the bearing capacity of the stiffened joint under compressive loads increases with the axial compressive strength of concrete, the volume fraction of steel rings and the ratio of longitudinal reinforcement in the joint area. The shear forces at the beam end also influences the bearing capacity of the stiffened joints, and the ductility decreases with the shear force. Based on the analysis results, a formula for calculating the bearing capacity of the reinforced joints under compression was established. The formula can be used as a good reference for designing circular steel-tube confined RC column-RC beam knee joints.