不同构造形式节点域箱形加强式工字形柱弱轴连接削弱型节点抗震性能分析

Seismic Behavior of Welded Steel Frame with Reduced Beam Section Connections of Box Strengthen-Joint Region Connection of I-Section Column for Weak Axis with Different Details

首先采用ABAQUS有限元软件,结合国内已通过试验验证的节点域箱形加强式工字形柱弱轴连接以及已有的焊接节点试验,验证了有限元模拟的有效性。在通过有限元软件ABAQUS模拟几种不同构造形式的削弱型节点,并与标准型节点在单调荷载作用下的承载力、循环荷载作用下的滞回曲线、骨架曲线、强度与刚度退化曲线、断裂指数等方面进行了对比分析,研究结果表明:节点域箱形加强式工字形柱弱轴连接节点局部削弱可以改善节点的破坏形态,实现塑性铰的外移,防止节点脆性断裂;当采用节点域箱形加强式工字形柱弱轴连接的节点形式,由于弱轴方向本身抗侧刚度较大,同时考虑建筑功能要求、抗震效果及经济性等指标,弱轴方向宜采用削弱型节点,其中腹板开孔型节点承载力及刚度没有过多的下降,且滞回曲线饱满,耗能性能及延性较好。而狗骨削弱型节点存在侧向失稳的问题,因此建议节点域箱形加强式工字形柱弱轴连接削弱型节点应采用腹板开孔型节点。

Firstly,the accuracy of finite element model is verified by quasi-static welding connection tests using the finite element software ABAQUS.Then ABAQUS is used to establish a non-linear finite element model,and load capacity under monotonic loading,hysteretic curve,skeleton curve,strength and stiffness degradation curve,fracture index under cyclic loading are compared and discussed in details.The results show the detail of locally weakened box strengthen-joint region connection of I-section column for weak axis can improve the failure mode of the connections,and realize the moving outward of plastic hinge,and prevent the occurrence of brittle fracture.Considering the building function requirements,seismic effect and economy,and the lateral stiffness of the weak axis direction is larger,so the weak axis direction should adopt the weakened connections,the bearing capacity and stiffness of the weakened connections are not weakened too much and the hysteretic behavior is stable,dissipation capacity and ductility of the weakened connections are better.In addition,the"Dog bone"type connection has the problem of lateral instability,so it is suggested that the connections should adopt web opening connections.