An Experimental Study of Bending Behaviour of Double Channel and Hollow Sections of Light Gauge Steel

This paper presents experimental results of the double channel and hollow sections of light gauge steel carrying a bending moment on their strong axis. The double channel sections were built from two channels which were joined using sufficient screws to form two combination models, i.e., Box Model (DC-Box) and Back to Back Model (DC-I). Bending behavior of five beam specimens: two specimens of Hollow Section, two specimens of DC-Box, and one specimen of DC-I, have been observed when they were subjected to two point loads which increased monotonically. It was found that the Hollow Section and DC-Box had the same failure model when they reached the ultimate load, i.e., permanent local buckling. Buckling occurred on top flange and web of the section, and the structures lost their resistance significantly. Meanwhile, elastic lateral torsional buckling prevented the DC-I specimen reached the higher load. The experimental results were compared to an analytical calculation based on the formula in the codes. Material properties obtained from tensile tests were used in the calculation. Comparison between the experimental data and the analytical results showed discrepancies within the range 18% - 59%. Based on this study, it is suggested a lower beam capacity of bending to obtain a conservative design of the structures.