BEHAVIOUR OF HSC ECCENTRICALLY LOADED SPIRALLY REINFORCED SHORT CIRCULAR COLUMNS

Abstract

Lateral confinement provided in the form of spiral reinforcement, greatly improves the ductility of lower strength concrete columns, leading to the expectation that similar .benefits would also occur in high strength concrete columns. The purpose of the present investigation was to experimentally establish the similarities or differences in behaviour between normal and high strength spirally reinforced short circular columns under eccentric compression with special reference to gain in strength, stress-strain curves, ductility and mid-height deflection. High strength concrete is known to be brittle when loaded to failure, confinement increased compressive strength and capacity to sustain large deformations without any strength loss. Axially loaded columns occur rarely in practice because some bending is always present, however, most investigations are limited to normal strength concrete. The experimental programme consists of casting seventy eight cylindrical specimens of size 150 mm x 1000 mm, y hichh include plain and reinforced specimens. Minimum 6 Nos. of longitudinal reinforcement with 8, 10 & 12 mm tor steel bars were used and 6 mm dia mild steel was used as transverse reinforcement at different pitches of 50, 80 & 120 mm. All specimens were tested a1 28 days under eccentric compression. The data recorded were ultimate load, longitudinal and lateral strains and mid-height