Behaviour of concrete filled steel tubular (CFST) short columns externally reinforced using CFRP strips composite

This paper focused on experimentally and analytically investigates the suitability of carbon fibre reinforced polymer (CFRP) strips composites in strengthening of CFST members under compression. The size and height of the columns were 91.5 × 91.5 × 3.6 mm and 600 mm respectively. CFRP fabrics was used as horizontal strips (lateral ties) with several other parameters such as the number of layers, width and spacing of strips. Among the 21 columns, eighteen columns were externally strengthened by CFRP strips having a constant width of 50 mm with the spacing of 30 mm and 40 mm, and the remaining three columns were reference column. Experimental results were revealed that external wrapping of CFRP strips provides restraint against the lateral deformation effectively and delays the local buckling of steel tube. Axial deformation control and load bearing capacity of the confined columns increases as the number of layers increases in addition to that increases in the load bearing capacity mainly depends upon the proper spacing between the CFRP strips. Analytical model was proposed herein for predicting the load bearing capacity of CFRP confined CFST columns.