Experimental study on seismic performance of variable cross section replaceable link

Abstract

This paper presents an innovative design for replaceable shear links, incorporating a variable cross-section that emphasizes concentrated plastic deformation in the energy-dissipating region. The design employs fully bolted connections involving non-energy-dissipating components, enabling both efficient elastic design and focused plastic behavior. To evaluate the seismic performance of this variable cross-section replaceable link, three section configurations were developed for cyclic loading tests: a low-yield-point (LYP160) specimen with an unchanged energy-dissipating region, a Q235 steel specimen with circular holes in the energy-dissipating region, and a Q235 steel specimen with elongated holes in the same region.Experimental results emphasize that plastic deformation is primarily localized in the energy-dissipating region, with failures characterized by buckling and tearing around the region's holes. Notably, the low-yield-point specimen exhibits an overstrength coefficient of up to 3.65, displaying a complete hysteresis curve, exceptional energy dissipation capacity, and a plastic rotation of 0.18 rad. Conversely, the elongated-hole specimen demonstrates notable overstrength exceeding 1.70, but its energy dissipation is compromised due to the weakened section. In contrast, specimens with circular holes exhibit an initial elastic stiffness similar to low-yield-point steel specimens, outperforming elongated-hole specimens by around 84% in stiffness. Additionally, a two-stage design method for bolted connections, accounting for bolt slip, is proposed. This approach enhances the overall understanding and utilization of these innovative replaceable shear links.