Axial compression capacity of concrete columns reinforced with corrosion-resistant hybrid reinforcement

Axial compression performance of concrete columns reinforced with varying combinations of 2304 duplex stainless bars and spiral, 316L stainless clad bars, and GFRP bars and spiral is examined under controlled conditions and after exposure to accelerated corrosion. The hybrid columns were reinforced with a combination of metallic and GFRP reinforcement. Columns reinforced with GFRP vertical bars and GFRP vertical bars were also tested for comparison. After corrosion exposure, the columns were tested under axial compression to failure. Columns with GFRP vertical bars and stainless steel spiral were less corrosion resistant and had smaller axial compression capacity compared to hybrid columns with stainless clad or stainless steel vertical bars and GFRP spiral. Columns reinforced with stainless steel spiral achieved two to three times the maximum axial displacement of columns reinforced with GFRP spiral. Axial compression capacity of hybrid columns in both controlled and corroded conditions was modeled using concrete confinement models for metallic and GFRP reinforcement.