Seismic performance of a novel viscoelastic damper for steel beam-column joints: Experimental and numerical analysis

Past seismic events such as the Northridge (1994) and Kobe (1995) earthquakes exposed the vulnerability of steel moment-resisting frames to brittle failures concentrated at beam–column joints. Although various damping and low-damage connection solutions have been proposed, many remain costly, mechanically complex, or difficult to implement at the joint level in practical applications. This study proposes a novel, compact viscoelastic damper specifically developed for steel beam–column joints, aiming to enhance energy dissipation and rotational capacity without compromising stiffness or load-bearing capacity. The damper combines layered elastomeric rubber, steel plates, and embedded lead cores, inspired by the fundamental mechanisms of lead–rubber seismic isolators but adapted for joint-level implementation. The seismic performance of the proposed system was investigated through cyclic tests on three beam–column joint subassemblies, including one reference specimen without a damper and two specimens with different damper configurations. In parallel, detailed nonlinear finite element models were developed and calibrated against experimental results. The results demonstrate that the proposed damper significantly improves displacement ductility and cumulative energy dissipation capacity compared to the undamped joint, while maintaining comparable strength and acceptable stiffness characteristics. These findings indicate that the proposed viscoelastic damper offers a practical, low-cost, and easily replaceable alternative for enhancing the seismic resilience of steel moment connections.