Experimental evaluation on the seismic performance of high-strength reinforcement beam-column joints with different parameters

This paper reports the results of cyclic load tests and analysis of full-scale beam-column joints using 600 MPa high-strength reinforcement as beam longitudinal reinforcements. The focus was on evaluating the effect of the relative length of beam bars through the joint (hc/d) on the seismic performance of the high-strength reinforcement beam-column joints, while the effects of variables such as axial compression ratio, shear compression ratio, and transverse reinforcement ratio were also discussed. The failure pattern, strength, stiffness, ductility, energy dissipation, and bond performance of each specimen under reciprocal loading were analyzed. The test results showed that applying high-strength steel bars improved the failure pattern, load-bearing capacity, and energy dissipation of the joints. The increase in hc/d improved the bond degradation of the high-strength reinforcement, which positively influenced the seismic performance of the joint. Conversely, high axial compression ratios and high shear compression ratios had a clear negative effect on the bond degradation and failure patterns when high-strength reinforcement used. A proposed equation for adjusting the hc/d in a highstrength reinforcement joint was also presented, which considered the effect of concrete strength and reinforcement strength on the bond performance of beam reinforcement.