RBS节点钢框架设计方法与极限承载力理论研究

Design method and ultimate bearing capacity study of steel frame structure with RBS connection

从极限分析理论出发,就翼缘削弱型节点(简称RBS节点)对结构破坏模式与极限承载力的影响进行研究.首先对美国FEMA提出的RBS节点设计方法进行分析,并讨论了该设计方法中的不足.针对上述不足,将极限荷载的唯一性定理推广到同时承受比例荷载与固定荷载的结构;对于满足强柱弱梁要求的框架结构,进一步论证了其横梁极限内力状态的唯一性.以此为基础,提出了针对美国FEMA RBS节点设计步骤的补充验算公式;针对组合破坏机构,提出了RBS节点设计新方法.其次,对RBS节点钢框架的极限承载力进行了理论推导,得到了极限承载力理论计算公式,同时明确了极限承载力的影响因素.最后,利用Abaqus有限元分析软件验证了上述理论研究结果的正确性.

The limit analysis theory is applied to investigate the influence of the reduced beam section(RBS)connection on the failure mode and the ultimate bearing capacity of the structure.Firstly,the limitation of the design method of RBS connection proposed by FEMA is demonstrated.To overcome the shortage,the uniqueness theorem of the ultimate bearing capacity is applied to the structure subjected to both proportional loading and fixed loading.For the frame structure with a strong column and weak beam,the uniqueness of the ultimate internal force state is further demonstrated.The existing design procedure of RBS connection in FEMA is modified by a supplementary checking formula,and a new design method is proposed for RBS connection with a combined failure mechanism.Then,a theoretical derivation of the ultimate bearing capacity of the steel frame structure with RBS connection is carried out to clarify the influence of the RBS connection on the ultimate bearing capacity,and a theoretical calculation formula of the ultimate bearing capacity is obtained.Finally,the theoretical result shows a good agreement with the numerical simulations conducted by the finite element analysis software Abaqus.