Innovative dissipative connection for steel braced frames: U-Conneciton

Abstract

In braced frames, the connection between braces and adjacent members are a suitable location for dissipating seismic energy in case of a strong seismic event. The overall lateral stiffness of the structure is not compromised, the compression braces may be protected from buckling and therefore increase the overall ductility. Within the scope of research project INERD, an innovative dissipative connection for braced frames was developed resorting to a U-bent plate. The connection consists of one or two bent U-shaped thick plates that connect the brace to the adjacent member. The energy dissipation takes place in the bent plate(s). In this paper, an analysis of the performance of the U-connection for braced frames is presented. Within the referred project, experimental tests on the connection device and on single floor braced frames, using the U-connection, were performed. The U-connection showed to be suitable for structures that proved to be not too sensitive to large displacement demands, thus mainly multi-story buildings with a limited number of stories. The results of these experiments were later used for the development of numerical models of braced frames implementing the U-connection. The paper focuses mainly on the numerical aspects, namely the incorporation of the connection behavior into the global structural model.