Investigation on Corroded Hss Tubular Members under Compression Strengthened with CFRP Composites

The main objective of this investigation is to assess the feasibility of strengthening of corroded (damaged) square hollow steel tubular sections subjected to compression and to develop or predict the suitable wrapping scheme of fibre reinforced polymer (FRP) to enhance the structural behaviour of it. For this study, compact mild steel tubes were used with the main variable being FRP characteristics. Carbon fibre reinforced polymer (CFRP) fabrics was used as horizontal strips (lateral ties) with other parameters such as the number of layers and spacing of strips. Among fourteen specimens, six were externally bonded by CFRP strips having a constant width of 50mm with a spacing of 20mm and the remaining six were externally bonded by CFRP strips having a constant width of 70mm with a spacing of 20mm, two columns were unbonded. Experiments were undertaken until the failure of columns to fully understand the influence of FRP characteristics on the compressive behaviour of the square sections including their failure modes, axial stress-strain behaviour, enhancement in the load carrying capapcity, and effect of distribution of CFRP layers. Finally, the behaviour of externally bonded hollow tubular sections was compared with one another and also with the control specimens. Evaluation of the results will lead to optimum CFRP jacketing/ wrapping arrangements for the steel tubes considered here.