Effect of the corner radius on the axial compressive performance of large steel-reinforced concrete columns confined by carbon fibre-reinforced polymer

This study investigated the effect of the corner radius on the axial compressive performance of large rectangular steel-reinforced concrete columns confined by carbon fibre-reinforced polymer (CFRP). Static compression experiments were conducted on one reference and five strengthened specimens. The results indicated that as the corner radius increased, both the strength and ductility of the confined columns also increased. The descending portion of the load-displacement curve gradually turned to ascending, and the CFRP strain became more uniformly distributed and high value. The numerical simulation of experimental columns showed that the area of effectively confined concrete zones increased with the corner radius. But when columns with side lengths larger than 350 mm were analysed, the study found that the stress increment of the confined concrete, as well as the proportion of the effectively confined area to the total section, decreased as the component size increased. Lastly, a formula for calculating the axial capacity of large-scale rectangular steel-reinforced concrete columns confined by CFRP was proposed based on the experimental and numerical results.