梁端翼缘扩大型连接的抗震性能研究

通过试验及数值分析方法研究了钢框架梁端翼缘扩大型连接节点的滞回性能、极限承载力、破坏模式、刚度及强度退化等抗震性能。研究结果表明:梁端翼缘扩大式节点可以将塑性铰转移到梁翼缘扩大端截面以外位置,避免梁端焊缝发生脆性破坏;加强侧板末端截面有明显突变和热影响区影响使钢材变脆应力集中现象严重,制约了节点塑性耗能深入发展;直接扩翼型节点塑性铰中心形成于扩翼圆弧段末端,远离柱翼缘,达到了塑性铰外移的目的;在循环荷载作用下,翼缘及腹板随局部屈曲塑性变形的不断积累,导致试件的强度出现退化;节点构造形式对抗震性能影响显著,直接扩翼型节点的塑性变形和耗能能力较好,推荐在强震区采用。

Seismic behavior study of widened beam flange connections

By the experiment and finite element analysis,the seismic-resisting behavior of the widened beam flange connections including the hysteretic behavior,the stiffness and strength degradation regulation and ultimate bearing capacity etc.were studied.Results of the research show that the plastic hinge of the reinforced beam flange connections can be effectively moved out of the widened beam flange section and the brittle break can be avoided near the welding seam at the end of the beam.For the widened side-plate connection specimens,the sharp change of beam section and heat-affecting zone can make the steel becoming brittle,lead to severe stress concentration at the range and restrict the further development of plastic energy consumption.The centers of plastic hinge of direct arc widened beam flange connections locate at the end of widened arc part which is far from the column flange surface and achieve the goal of the plastic hinge outward-moving.The degradation of the strength of the specimen occurs with the local buckling of plastic deformation continuing to accumulate under the cyclic loading.The structural forms of the connection significantly impact the seismic performance.The plastic deformation and the energy dissipation capacity of the direct arc widened beam flange connections is much better,which is recommended in the earthquake zone.