基于整体效能的不等跨半刚性连接钢框架梁柱子结构抗倒塌设计

Anti-collapse Structural Design of Semi-rigid Beam-column Joint of Unequal Span Steel Frame based on Overall Efficiency

不等跨半刚性连接钢框架梁柱子结构在连续倒塌工况下短跨节点由于变形较大而率先发生破坏,结构整体的承载力将快速下降,长跨因失去短跨支持,效能得不到充分发挥。基于增大短跨节点变形能力以提升长跨效能利用的设计理念,针对顶底角钢腹板双角钢半刚性连接节点,探究增加短跨顶底角钢厚度、改变短跨梁翼缘螺栓孔形式等对子结构长短跨抗力机制发展的影响,并通过引入协同工作系数,定量说明长跨效能的发挥程度。结果表明,短跨顶底角钢厚度的增加使得短跨梁机制和悬链线机制提供的抗力明显增大,由于长短跨的协同工作,长跨梁机制和悬链线机制得到进一步发挥;在短跨梁翼缘开设长圆孔,使短跨节点具备更大的变形能力,其倒塌抗力得到提升。针对短跨栓孔长度和顶底角钢厚度的设计可使不等跨梁柱子结构的整体效能得到充分发挥,实现了长短跨协同抵抗外载的理想状态。

Under continuous collapse conditions,the short-span joints of semi-rigid steel frame beamcolumn structures with unequal spans are first destroyed due to large deformation and the overall bearing capacity of the structure will decline rapidly.The long-span will lose its short-span support,and the performance cannot be fully utilized.Based on the design concept of increasing the deformation capacity of short-span joints to improve the utilization of long-span efficiency,aiming at the semi-rigid connection joints of the double angle steel of the steel web at the top and bottom angles,this paper explores the influence of increasing the thickness of short-span top and bottom angle steels and changing the bolt hole shape of the short-span beam flange on the development of long-span resistance mechanism of sub-structure,and quantitatively explains the exertion degree of long-short-resistance by introducing cooperative work coefficient.The results show that the increase in the thickness of the shortspan top-bottom angle makes the resistance provided by the short-span flexural mechanism and the catenary mechanism significantly increase.Due to the long-short-span interaction,the long-span flexural mechanism and the catenary mechanism are further developed;Long bolt hole on the short-span beam flange is opened.The long round hole makes the short-span node have greater deformation ability,and the anti-collapse capability is improved.The design of the short span bolt hole length and the top and bottom angle steel thickness can make the overall performance of the unequal span beam column sub-structure fully exerted,and realize the ideal state of long and short span synergistic resistance to external loads.