Experimental investigation of precast concrete hybrid-steel concrete beam-column connections with self-centering system and steel slit dampers

Abstract

This study introduces a precast concrete hybrid-steel concrete beam-column connection incorporating a self-centering system and steel slit damper (SSDs) for seismic resistance. The objective is to utilize post-tensioned steel to enable the structure to return to its original position (self-centering) after an earthquake, while SSDs are designed to yield under seismic loads, absorbing and dissipating energy to mitigate potential damage to the beam structure. The end of the beam is also installed with H-section steel beams to reduce the damage from SSDs. To evaluate the seismic performance of the proposed structure, the study applies the capacity design approach to control damage at the connection region. All test specimens were designed and tested following ACI 374.1-05, using quasi-static reversed cyclic loading. The behavior of two connection specimens was compared: 1) cast-in-place beam-column connection and 2) hybrid-steel concrete beam-column connections with unbonded post-tensioned steels and steel slit damper (SSD). The structural performance was assessed based on the force-displacement relationship, energy dissipation capacity, and stiffness. The test results indicate that a crack formed at the beam-column interface under lateral loads, known as a gap opening. However, the post-tensioned steel effectively closed this gap, demonstrating self-centering capability, while the SSDs efficiently dissipated energy through yielding. Furthermore, the specimens exhibited stable behavior under large deformations, withstanding beam rotations of up to 2% comparable to the cast-in-place beam-column connection.