K形管板节点板稳定承载力研究

《钢结构设计规范》(GB 50017—2003)附录F中介绍了桁架节点板在斜腹杆压力作用下的稳定计算,假定受压区节点板分成三个区同时受压,把各个区当成轴心受压构件分别计算其稳定性,但只考虑了腹杆轴力的影响,没有考虑腹杆弯矩的影响。实际上,腹杆弯矩的存在会导致三个区中边上的两个区分别承受压应力和拉应力。因此,在对平面K形管板节点的节点板稳定承载力进行分析时,考虑了腹杆轴力与弯矩的共同作用,并假定受压区节点板分成三个区同时承受外力,把受压区当成轴心受压构件计算其稳定性,提出了平面K形管板节点在斜腹杆压力作用下节点板的稳定承载力计算公式。最后,与按照小挠度理论推导的稳定承载力计算公式进行了对比,得到《钢结构设计规范》(GB 50017—2003)中节点板稳定承载力的结果偏于安全的结论。

Research on the stability of gusset plate of tube-gusset K-joints

The stability calculation method of truss gusset plate under oblique bracing member pressure is introduced in appendix F in Code for design of steel structures(GB 50017—2003).In this code,it assumes that the compression zone in the gusset plate is divided into three zones under pressure,and the stability of every zone is calculated as an axial compression member.It only considers the effect of axial force in the bracing member,but the impact of bending moment is neglected.In fact,the existence of bending moment will lead the two zones in the edge of the three zones to subject to compressive stress and tensile stress respectively.Therefore,when analyzing the stability capacity of the gusset plate of tube-gusset K-joint,the combined effect of axial force and bending moment in the bracing member was taken into account,and it assumed that the compression zone in the gusset plate was divided into three zones subject to external forces at the same time,then it also assumed the compressive zone as a axial compression member to calculate the stability capacity.As a result the capacity formula for calculating the gusset plate stability of tube-gusset K-joints under oblique bracing member pressure was introduced.A comparison with the stability capacity calculation formula considering the small deflection theory was carried out.The results reveal that the stability calculation method in Code for design of steel structures(GB 50017—2003) is conservative.