Axial behavior and strength of yLC composite columns

Experimental studies were performed on the proposed yLC (Concrete with y-shaped steel sheets and L-shaped steel angles) composite column whose external surface was made of y-shaped steel sheets and steel angles, into which concrete was poured. This composite column has the sectional capacity developed by the composite action of steel and concrete, while efficiently reducing the construction work time due to the abridged form work. A total of eleven stub column specimens were prepared and tested under concentrically axial loading. The axial behavior and compressive strength of the proposed composite column were investigated, and modified equations from ANSI/AISC 360-05 Specifications for predicting axial-load capacity were proposed. The post-peak behavior of the tested specimens was considerably affected by the width-thickness ratios of the steel angles and by the welding method between the steel sheets and steel angles. Some recommendations were given to make the proposed composite column more ductile.