Classification System for Rigid and Semirigid Connections

Abstract

A new classification system for beam-to-column connections is proposed in terms of the boundary between rigid and semirigid connections. Some typical subassemblages of multistory frames are chosen to consider the layout and member details of the structural systems in the classification. The connection model used for this classification is the power model proposed by Kishi and Chen. In this connection model, the connection curves for the respective connection types can be determined by their initial stiffness and ultimate moment capacity. The boundary between rigid and semirigid connections is established in terms of these two parameters by taking into account the elastic-plastic behaviors of the structural assemblages at the serviceability limit state along with the ultimate limit state. Furthermore, the required rotational capacity is calculated for the connections classified as rigid. The validity of the proposed classification system is examined by analyzing the overall behavior of semirigid frames. As a result, it is confirmed that the new classification criteria provides a more rational boundary compared with the existing classification systems.