Experimental studies of the seismic behavior of EKBFs subjected to lateral loading

Abstract

In this paper an experimental study on the behavior of a new and practical technique of lateral bracing for steel frame construction for two levels of performances, is presented and discussed. Eccentrically Knee Bracing (EKB) technique, as it is called in this paper, is made up of four structural elements, the knee element, the diagonal brace element, the link element and the column elements. The knee and link elements are a fuse-like element that dissipates energy by the formation of plastic hinges, when the building is subjected to moderate and severe lateral loads, respectively. The diagonal brace element, on the other hand, provides the required level of lateral stiffness and remains in the elastic range at all time. In large earthquakes, both of them contribute in dissipating energy. Two half-scale EKB were tested using the SAC loading protocol and an innovative loading protocol. The general test arrangement, specimen details, and most relevant results such the stiffness, shear strength, cumulative dissipated energy and other major seismic parameters in the EKB are explained. Using experimental and analytical models, the energy dissipation characteristics of the EKBs and an EBF are presented. Reasonable agreement with the experimental results is observed.