Experimental and numerical study on a buckling-restrained stiffened rib multi-stage energy-dissipating plastic hinge damper

To address energy dissipation demands under varying earthquake intensities, this study proposes a novel buckling-restrained stiffened rib multi-stage energy-dissipating plastic hinge damper, which realizes synergistic frictional and mild steel deformation energy dissipation via an optimized structural design. Combined with quasi-static tests and Abaqus simulations, the effects of key parameters (energy-dissipating steel plate thickness, stiffening rib height, bolt preload, and slip segment length) on seismic performance are systematically analyzed. Results show that the damper’s energy dissipation mode depends on the relative magnitude of the energy-dissipating steel plate’s yield capacity and frictional force, dividing it into three categories: Category I (yield capacity greater than friction) with hysteretic curves exhibiting two-stage behavior ("first friction, then friction and mild steel deformation"), gradually increasing bearing capacity, and optimal energy dissipation; Category II (yield capacity less than friction) relying solely on the mild steel deformation with low bearing capacity; and Category III (yield capacity relatively close to friction) featuring early synergistic work but later instability due to sudden bearing capacity drop. Thus, Categories II and III should be avoided. Parametric analysis reveals that bolt preload determines friction-stage performance (higher preload increases first-stage capacity but may restrict the second-stage to mild steel deformation), plate thickness and rib height mainly affect second-stage capacity (larger values enhance Category I peak capacity), and slip segment length only delays mild steel activation without impacting capacity. Damage is concentrated on replaceable energy-dissipating steel plates, with other components showing low stress, thus achieving controllable damage and rapid post-earthquake repair as designed.