High-strength reinforcement effects on the seismic behaviour of beam–column joints

Technological developments have facilitated the production of high-strength reinforcements (HSRs) with increasingly appropriate characteristics. The application of HSRs has many benefits, one of which being a decrease in overall construction expenditures. In this research, the influences of HSRs (with yield strengths of 500 and 580 MPa) as longitudinal and transverse reinforcements in three beam–column joints were experimentally studied. The effects of the HSRs on drift, stiffness degradation, displacement, energy dissipation, ductility, cracking patterns and damage indices (DIs) were investigated. The experimental results showed that all the specimens achieved drift ratios in excess of 4% before they showed a critical decay in lateral strength. The energy dissipation and ductility of the specimens were also reduced with the use of HSRs. However, HSR application as stirrups showed better effects than HSR as longitudinal reinforcement. Regarding DIs and stiffness degradation, it was found that the application of HSR increased the intensity of the damage distribution in the specimens. Finally, although crack numbers decreased by using HSRs, the crack widths and depths increased.