Influence of Damper Strength on Self-Centering Performance of Beam–Column Connection: Experimental and Analytical Validation

The seismic performance of precast concrete structures is highly dependent on the behavior of their connections. Hybrid post-tensioned (PT) connections have shown excellent strength, stiffness and self-centering capacity. However, damage is concentrated in the mild steel bars, which cannot be replaced after an earthquake. Recent research has focused on developing replaceable metallic dampers, but most devices require complex fabrication and installation. This limits their application in precast construction. To address these limitations, this study proposes a novel replaceable circular hollow section (CHS) damper with easy installation and replacement. The damper geometry is tailored to provide high tensile strength while limiting compressive strength to improve self-centering capacity. The present study investigates the influence of the damper strength contribution on energy dissipation and self-centering performance using a parametric approach. A finite element (FE) model was developed and validated with results from experimental tests. The model was further validated by the developed analytical procedure. The results show that when the CHS damper contributes 37.5% of the total moment capacity, the connection exhibits only 2.6 mm of residual displacement at a 4% drift ratio. The optimum contribution of the damper to maximum energy dissipation and self-centering was found to be 35–50% compared to mild steel bars which were 20–30%. Therefore, the novel CHS damper provides a superior and practical alternative to mild steel bars. It provides excellent seismic performance, enhances self-centering and is easily replaced after an earthquake.