箱形节点域DRBS型弱轴连接抗震性能有限元分析

Finite Element Analysis on the Seismic Behavior of DRBS Weak-Axis Connection with Box-shaped Region

为了研究箱形节点域翼缘双削弱(double reduced beam section,DRBS)工字形柱弱轴连接节点的抗震性能,设计了两个系列模型。应用有限元软件Abaqus对第2个削弱区段的长度和深度的取值进行了研究,分析了节点的破坏形式、等效塑性应变、承载力、延性、塑性转动能力及耗能系数等,并与箱形节点域翼缘削弱(reduced beam section,RBS)型弱轴连接节点进行了对比分析。结果表明:在循环荷载作用下,在第2个削弱区段的削弱长度等于第1个削弱区段长度且第2个削弱区段的削弱深度取值宜略大于美国FEMA-350规范推荐的上限值时,箱形节点域DRBS型节点具有良好的抗震性能。与RBS型节点相比,DRBS型节点的承载力降低不明显,但是显著降低了最大等效塑性应变,提高了节点的延性和塑性转动能力。此外,DRBS型节点减缓了梁腹板和翼缘的局部屈曲的发生,从而提高了节点的累积耗能能力。

A new double reduced beam section(DRBS)connection based on box-shaped region connection for weak-axis I-shaped column is introduced and the seismic behavior of the connection is studied using software ABAQUS.A parametric study is conducted to evaluate the behavior of connections.The results show that,following the limitations and guidelines stated in this research,when the length of the second reduced zone equals to the length of the first reduced zone and the depth of the second reduced section is slightly larger than the upper limitation recommended by FEMA-350,the DRBS connection exhibits outstanding seismic behavior.Comparing with RBS joint,the bearing capacity of the DRBS joint is not significantly reduced,but the maximum equivalent plastic strain is significantly reduced,and the ductility and plastic rotation capacity are increased.Moreover,the DRBS joint slows the occurrence of local buckling of beam webs and flanges and then increases the accumulated energy absorption before local buckling occurs.