屈曲约束支撑方钢管高强混凝土框架节点的有限元分析

Nonlinear FEA on Connections of Steel Beam to High-strength Concrete Filled Square Steel Tubular Column in BRBF

目的研究带屈曲约束支撑的方钢管高强混凝土柱-H型钢梁削弱节点的受力性能,找出翼缘削弱方式和削弱程度等因素对其受力性能的影响.方法通过ABAQUS有限元分析软件,对18个传统型节点和削弱型节点模型进行单调荷载作用下的拟静力分析,对比分析在不同轴压比、混凝土强度、梁柱线刚度比和BRB屈服承载力的影响下,传统型节点和削弱型节点的破坏机理.结果梁端翼缘的削弱不会降低屈曲约束支撑的屈服承载力和极限承载力,不会降低节点的承载能力.建议节点的削弱参数按照a=(0.3~0.7)×b_f,b=(0.75~0.85)×h_b,c=(0.2~0.25)×b_f进行取值.结论削弱型节点的梁端塑性铰出现在削弱部位,梁端翼缘的削弱起到塑性铰外移的作用,减小了节点区域应力集中,有利于实现"强柱弱梁、强节点"的抗震设计目标.

This paper was proposed to investigate mechanical behavior of connections of reduced H-shaped section steel beam to high-strength concrete filled square steel tubular column in buckling restrained braced frame system（BRBF）,and further to discover such key factors influencing performance for BRBF beam-column-brace connections as reduced type,depth,and so on.18 FE models including different key factors（column axial load level,concrete strength,beam-to-column stiffness ratio and BRB yield force） are established and analyzed using the commercial softwareABAQUS,in which a constant axial load on column and two lateral monotonous load on the connection are imposed.The analysis results indicate that the BRB yield force and ultimate bearing capacity didn’t decrease because of reduced beam section,the bearing capacity of reduced beam section connections didn’t decrease.Determine the length,depth and location of the beam flange reduction,based on the following：a=（0.3~0.7）×b_f,b=（0.75~0.85）×h_b,c=（0.2~0.25）×b_f.All of the following conclusions are draw n：plastic hinges in beams located at the beam reduced part;stress concentration in beam-column-brace joint region could be decreased;structure design goal of ＂strong-column-weak-beam and strong-connection＂ could be achieved.