Prediction of Axial Compression Behavior of Confined Concrete Columns Considering the Effect of Cryogenic Temperatures

Abstract

The axial compression performance of confined reinforced concrete columns in cryogenic temperature environments is affected by the mechanical properties of reinforcement and concrete materials. The properties of reinforcement and concrete material vary greatly in cryogenic environments. To investigate the axial compression behavior of confined reinforced concrete columns at cryogenic temperatures, specimens with stirrup-confined and carbon fiber–reinforced polymer (CFRP) confined were simulated respectively, considering the impact of cryogenic temperatures on material properties. The various stirrup and CFRP ratios were applied at different temperatures from 20°C to −120°C. The results indicate that decreasing temperature improves the peak load and initial stiffness while reducing peak strain and ductility. The ductility of specimens improves with the increasing stirrup and CFRP ratios, while the increment at cryogenic temperatures is less than that at 20°C. At −120°C, the hoop strains at the peak point and descending branch are greater than those at 20°C. The confined strength increases linearly with the increasing confinement ratio, while the decreasing temperature reduces the growth rate. The confinement effects are weakened as temperature drops. Based on the numerical results, a compression model that can reflect the influence of cryogenic temperatures was established. The model can provide better predictions of confined strength, peak strain, and stress–strain curves of confined reinforced concrete columns under axial compressive load and cryogenic temperatures.