加强与削弱并用型工字形柱弱轴连接节点滞回性能分析

Hysteretic Behavior Study of I-Section Column Weak-Axis Connection with Strengthened-Weakened Beam End

为了减小钢框架梁柱弱轴连接中柱腹板上的应力水平,提出了在梁端加过渡竖板的方式以使得柱翼缘更好地参与受力。同时为了使塑性铰不出现在梁柱连接焊缝处,对梁翼缘进行削弱处理,最终提出了一种新型的梁端加强与削弱并用的梁柱弱轴连接(SWWC)形式,并运用有限元软件ABAQUS对已有的RBS型工字形柱弱轴连接节点的试验进行模拟验证后,对此类节点进行循环荷载作用下的受力性能分析。结果表明:在梁端加过渡竖板可以明显降低节点域的Mises应力水平,使得梁截面的屈曲主要集中在竖向板的外侧;在梁端加过渡竖板的同时对梁翼缘进行削弱处理可以使塑性铰外移;随着削弱深度c的增加,节点的承载力逐渐降低,RBS削弱处的屈曲发展得越充分,削弱起始位置至梁端的距离a和削弱区域的长度b对节点的承载力影响会很小,随着参数a或b的增加,梁上塑性铰中心逐渐远离梁翼缘焊缝处;建议削弱参数c=0.17bf,a取值范围为0.65bf^0.70bf,b=0.75hb,其中bf和hb分别为梁翼缘宽度和梁截面高度。

In order to reduce the stress level of the column web in beam-column weak-axis connection in steel frame,this paper proposes a vertical transition at the beam-end to make the column flange transfer the force in a better way.Also,to avoid the plastic hinge occurred in the beam-column connection welds,the reduced beam section(RBS)is introduced in this connection,and then a new strengthened-weakened weak-axis connection(SWWC)is proposed.The finite element software ABAQUS is used to simulate the existed RBS I-section column weak-axis connection specimen.After verifying the model,the mechanical behavior of SWWC under cyclic loading is evaluated.Results show that adding the vertical transition at the beam-end can reduce the Mises stress level of the panel zone and make the beam buckling outside the vertical transition.Introducing the RBS in the beam flange can move plastic hinge away from beam-column connection.The deeper reduced part c leads to a lower bearing capacity and fully buckling of RBS region.The distance between the starting part of the reduced region and the beam-end,a,and the length of the reduced part,b,have insignificant effects on the bearing capacity of the connection,and with the increase of aand b,the center of the plastic hinge is gradually moved away from beam flange welds.The reduction parameters of c=0.17 bf,a=(0.65~0.70)bf,and b=0.75 hbare suggested for use in SWWC,where the bfand hbis the beam flange width and beam height,respectively.