Plastic Behavior and Design Methodology for Curved Members in Seismic Applications

Abstract

Curved steel members, widely utilized in modern architectural and structural applications, offer aesthetic, functional, and structural benefits. However, the plastic behavior of these members, particularly the yield, buckling, and ultimate strengths under various boundary conditions, remains insufficiently investigated. Unlike straight members, curved members lack well-established design equations and connection design guidelines, limiting their use for earthquake-resistant applications. This study investigated the plastic behavior of curved members through static analysis and extensive parametric studies, focusing on initial elastic stiffness, plastic strength, slenderness effects, and section compactness. Estimation equations for yield strength and buckling behavior with pinned- and fixed-boundary conditions were developed and validated using numerical simulations, demonstrating high accuracy. The findings further contributed to developing a connection design methodology that enhances material efficiency while preventing overly conservative designs. Moreover, a boundary constraint condition was identified to effectively control the yielding mechanism and achieve the desired plastic behavior. The proposed estimation equations and design recommendations provide a foundation for the practical implementation of curved members in seismic applications, improving structural efficiency, design flexibility, and functionality.