The Consideration of Different Aspects of Design of Eccentric Braced Frames (EBF) according to AISC-Seismic Provisions

The eccentrically braced frame (EBF) is a hybrid lateral force-resisting system composed of two conventional framing systems: the moment-resisting frame and the concentrically braced frame. The EBF serves to combine many of the individual advantages of each conventional framing
system and minimizes their respective disadvantages. Specifically, eccentrically braced frames possess high elastic stiffness, stable inelastic response under cyclic lateral loading, and excellent ductility and energy dissipation capacity. The eccentrically braced frame has become one of the most common framing systems in regions of high seismicity. Researches on the behavior of EBFs commenced in the mid-1970s and now provisions for the analysis, design, and detailing of EBFs have been introduced into seismic regulations and guidelines. Although EBFs are used widely as the earthquake resisting system in Iranian steel buildings, there are common mistakes in configuration and design of this system in “Iranian Practice”. This paper describes the most important factors which should be considered necessarily in proper design of EBFsaccording to seismic provisions given in AISC (American Institute of Steel Construction) hereafter referred to as AISC-Seismic Provisions. This code is one of the most reliable codes which is used widely in consideration of seismic behavior and also design of steel buildings in areas of high seismicity.