Behaviour of high strength axially loaded concrete columns confined with helices

This paper presents an experimental study of the behaviour of four HSC columns confined by helical reinforcement of 500 MPa and with 500 MPa longitudinal reinforcement. Two NSC columns confined with a 500 MPa-grade helix and two confined with a 250-grade helix, all with 400-grade longitudinal bars were also tested. The helices were made of 10 mm diameter bars and had a constant diameter of 160 mm. A comparison on the effect of the pitch sizes for the helical reinforcement is made with the use of 50 and 75 mm pitches as well as the effect of the distribution of the longitudinal bars. With this variation in design, a higher strength, yet more ductile column can be achieved.