Performance of Plain Concrete Column Confined with Cold-Formed Steel Subjected to Axial Compression

Thin gauge sheets of cold-formed steel are commonly utilized in non-structural elements such as pre-engineering buildings, roofing sheets, and frames. An investigation to explore the potential use in structural aspect of these steel sections in civil engineering as the confinement material for the column is conferred through this report. The main intention of this investigation is to study the effect of confinement of cold-formed steel lipped channel built-up tubular column in filled with concrete. For this an experiment study was carried out for 12 columns of height 500 mm having the square cross-section of side 140 mm filled with two different grades of infilling material M30 and M40 were cast. Out of 12 columns 6 number of columns were confined with connected channel-lipped sections of thickness 2 mm each, and another 6 number of columns were unconfined specimens. The aspect ratio of depth to width is 1.0, and the depth-to-plate thickness ratio for the confinement steel is 70. These columns were tested on a 2000 kN capacity universal testing machine under axial compression. The parameters including ultimate bearing capacity, axial shortening, load vs deflection curve, ductility index, failure pattern of the concrete columns was studied. The study showcased that the ultimate bearing capacity is improved with the addition of the confinement material. The effect of M40 grade concrete is prominent in unconfined specimens when it is compared to confined specimens. The confinement restricts the axial shortening of the column specimens due to its triaxial effect on the infilled concrete. Crushing failure of the concrete is more prominent in case of the unconfined specimens as compared to confined one. The prediction of EC4 is in good agreement to the experimental results, whereas AISC overestimates the strength.