Finite element modeling of square high-strength concrete short columns longitudinally reinforced with steel equal-angles under axial loading

Abstract

Conventional steel bars in Reinforced Concrete (RC) square columns are utilized as longitudinal reinforcement and steel ties are utilized as transverse reinforcement for concrete confinement. The concrete confinement in RC columns with square section is less than that with circular section. Recently, Steel-Equal Angle (SEA) as longitudinal reinforcement has been investigated for square RC columns. The RC columns with SEA as longitudinal reinforcement exhibit higher strength and ductility than the RC columns with conventional steel bars as longitudinal reinforcement. However, experimental and computational investigations have been very limited on RC columns with SEA as longitudinal reinforcement. Existing studies investigated only the effects of lateral tie spacing on the performance of RC columns reinforced with SEA sections. However, the effects of the other important column parameters, such as the width and thickness of SEA sections, yield stress of SEA sections, and the concrete compressive strength, on the axial performance of RC columns reinforced with SEA sections have not been fully investigated yet. This study develops finite element (FE) models for quantifying the behavior of axially loaded square RC short concrete columns reinforced with SEA. The inelastic buckling of SEA cross-sections and the effects of concrete confinement are considered in the simulation. The accuracy of the FE analysis is verified using available test results. The influences of material and geometric properties on the compressive behavior of square RC short concrete columns incorporating SEA are studied. The results show that the model accurately estimates the behavior of square SEA reinforced concrete short columns. Moreover, the width of the SEA sections, the concrete compressive strength, and the lateral tie spacing have the most significant effects on the performance of SEA reinforced concrete columns subjected to axial loads.