Evaluation of Self-Compacting Concrete Columns Reinforced with Steel and FRP Bars with Different Strengthening Techniques

Abstract

This study evaluates the overall behaviour of self-compacting short concrete columns with different reinforcement types. Major parameters, including reinforcement-type, confinement techniques and the slenderness ratio of columns, are studied. The FRP tube and spiral stirrups with two different volumetric ratios are considered as strengthening techniques. The mode of failure, axial compressive load, load-displacement curve, stress-reinforcement bars strain curve, ultimate, ductility and effect of the slenderness ratio are the main results obtained to evaluate the different column behaviours. The slenderness ratios have the same effect on column capacity for the different strengthening techniques, which have approximately 5% and 10% for the slenderness ratios of 6 and 8, respectively. The column capacity in the case of steel bars reinforcement is higher than when using FRP bars by approximately 22% of the column capacity. In terms of the reliability of different international code equations for the results of the tested columns, using CAN/CSA and ACI codes, discrepancies were noted between the steel and FRP as the main reinforcement for different code results. The columns reinforced by steel bars exhibit strong agreement with the ACI and Canadian specifications on the contrary FRP reinforcement, when neglecting its effect in these code recommendations.