翼缘削弱型钢梁的整体稳定性分析

针对钢框架梁翼缘削弱式(RBS)节点梁的整体稳定性能进行了分析。采用能量法研究了不同荷载作用下RBS 梁的整体稳定性能, 将梁翼缘削弱段刚度采用等效折减刚度进行分析, 得到RBS 梁侧向弯扭失稳的临界荷载, 并与等截面梁临界荷载进行对比。讨论了不同削弱参数下RBS 梁的临界弯矩变化规律, 并通过有限元数值计算验证了削弱参数对RBS 梁弯扭失稳临界弯矩的影响。研究结果表明:RBS 梁削弱参数整体对侧向弯扭失稳影响明显, 其临界弯矩值较同尺寸的普通钢梁明显降低, 工程设计中应考虑其不利影响;RBS随梁跨度的增加, 削弱段局部刚度对整段梁的刚度影响作用减弱, 当RBS梁的高跨比较小时, 可以忽略削弱参数对临界弯矩的影响。

GLOBAL STABILITY ANALYSIS OF STEEL BEAM WITH REDUCED FLANGE

Global stability of the beam with reduced beam section (RBS) connections in steel frames is analyzed. The global stability of the RBS beam under different loads is studied using energy method; with the stiffness of the reduced region replaced by the equivalent reduced stiffness, the critical load of the RBS steel beam is obtained and compared with that of the ordinary steel beam. The variation of the critical moment of the RBS beam with cut dimensions is discussed, and the effects of cut parameters on the critical moment of RBS beam flexural-torsional buckling are verified by the finite element method. The results show that reductions have great effect on RBS beam flexural-torsional buckling, and the critical moment decreases obviously compared with that of the ordinary beam, so adverse effect should be considered in engineering design. The effect of beam cut section on beam stiffness decreases as the beam span increases, so the effect of cut dimensions on the critical moment of RBS beam can be neglected when the ratio of beam height and span is small.