Improving the Seismic Performance Of Eccentrically Braced Frame (EBF) Steel Structures Through the Application of Medium-Length Links

Abstract

Eccentrically Braced Frames (EBFs) are widely recognized for their capacity to combine structural strength, stiffness, and ductility, making them an ideal solution for earthquake-resistant design. At the core of this system lies the link beam, whose inelastic deformation behavior determines the overall energy dissipation capacity of the frame. Traditional link designs favor short and long configurations, which are characterized by shear or flexural yielding, respectively. However, medium-length links—capable of simultaneously activating both shear and flexural mechanisms—offer an advantageous compromise between strength and ductility. Despite their potential, medium-length links are underutilized due to historical design conservatism and limited code recognition. This paper presents a comprehensive analysis of the performance characteristics of medium-length links through a synthesis of recent experimental and computational studies. It also identifies emerging innovations in detailing, materials, and modeling approaches that can optimize EBF systems for enhanced seismic resilience. The results support a performance-based shift in design philosophy that leverages medium-length links to improve the safety, reliability, and sustainability of steel buildings in seismic regions.