Experimental investigation of precast SRC columns with bolted steel-core joints under cyclic loading

This study experimentally investigates the cyclic lateral load behavior of precast steel-reinforced concrete (SRC) columns incorporating bolted steel-core joints. Two joint configurations with different internal steel reinforcements and two axial load ratios were considered to evaluate their effects on seismic performance. Cyclic loading tests were conducted under constant axial load, and the responses were assessed in terms of strength, deformation capacity, stiffness degradation, energy dissipation, and hysteretic damping. The results show that the jointed specimens achieved approximately 85–95 % of the peak strength of the monolithic column, while specimens with an axial load ratio of 12 % exhibited deformation capacities up to 106 % higher than that of the monolithic specimen. The internal reinforcement configuration significantly influenced deformation distribution, with cross-shaped reinforcement promoting distributed deformation and insert-type reinforcement enhancing structural continuity and energy dissipation. Increasing the axial load ratio increased peak strength and initial stiffness but reduced deformation capacity and energy dissipation due to shear-dominated and brittle behavior. These findings demonstrate that bolted steel-core joints can provide adequate seismic performance for precast SRC columns, provided that joint configuration and axial load effects are appropriately considered.