钢框架弱轴梁端翼缘侧板加强式节点滞回性能有限元分析

Finite element analysis on hysteretic behavior of joint with side-plate reinforced beam flange weak-axis connections of steel frames

钢框架梁端翼缘侧板加强式节点旨在改善梁柱节点的抗震性能.本文基于新型节点域箱形加强式工字形柱弱轴连接的研究成果,提出梯形侧板加强式节点的滞回性能研究.利用有限元软件对此类节点进行低周反复荷载作用下的有限元变参模拟分析,研究梯形侧板长度、宽度及坡度对该类节点力学性能的影响.研究结果表明:梯形侧板加强式节点均在距蒙皮板约2/3梁高处梁全截面发生明显的屈曲变形,形成明显的塑性铰并有效外移.节点域处应力较小且形状保持完好,具有"强节点域"特征.侧板长度对节点的抗弯能力有明显的影响,坡度主要影响延性及塑性变形能力,而侧板宽度对节点的滞回性能影响相对不明显.建议侧板长度取梁高的0.6~0.75倍,坡度取1∶2~1∶3.

The side-plate reinforced beam flange of steel frames is a strengthened connection aimed at improving the seismic behavior of beam-column joints.Based on the study results of a new kind of connection with box-strengthen joint region for weak axis of I-section column,a trapezoid side-plate reinforced beam flange connection was proposed and analyzed on the hysteretic behavior.In order to study the effects of length,width and angle on the performance of this kind of joint,variable parameters analysis under cyclic loading were understood with ABAQUS.The results show that the trapezoid side-plate reinforced joints all had notable buckling deformation at beam full section with length of 2/3 beam height to the skin panel.Distinct plastic hinges were produced and relocated effectively.The stress in joint region is less and the shape preserves well,marked by‘strong joint region'.The length of side-plate affects the capacity visibly,and angle mainly changes ductility and plasticity of joint,while the thickness shows little influence on the hysteretic behavior.Suggested side-plate length is 60%~75% percent of beam height,side slope:1∶2~1∶3.