Effect of corner radius on axial compressive performance of steel reinforced concrete rectangular short columns confined by carbon fiber reinforced polymer composite

In order to study the effect of corner radius on axial compressive performance of large scale steel reinforced concrete rectangular short columns confined by carbon fiber reinforced polymer(CFRP) composite, the static axial compression experiment were conducted on one contrast specimen and five strengthened specimens. The results indicate that with the increasing corner radius, both the strength and ductility of the confined columns increase, the descending portion of the load-displacement curve after the peak load point gradually turns to ascending portion; the circumferential strain of CFRP composite sheets also gets higher working value and more uniform distribution. Through numerical analysis, it was seen that with the corner radius increasing, the area of the effectively confined concrete zone on the cross-section increases, the axial compressive stress distribution of concrete tends to be uniform, and the stress in the core area surrounded by steel increases significantly. Then the different confined concrete areas in cross-section were divided, and the core area surrounded by steel was set as the high-strength confined concrete zone. The superposition formulation of the axial bearing capacity of steel reinforced concrete rectangular short columns confined by CFRP composite was proposed. The calculation results show that increasing the corner radius significantly reduces the cross-sectional area of the large-size steel reinforced concrete rectangular columns, but improves the axial compression bearing capacity.