CFRP Strengthening of Web Perforated CFS Lipped Channel Short Columns: An Experimental Study

Abstract Axial compression tests on cold-formed steel (CFS) web perforated lipped channels strengthened with carbon fiber reinforced polymer (CFRP) were reported in this paper. The primary aim of this study was to experimentally investigate the influence of CFRP strengthening on the stability, axial strength and stiffness of the CFS web perforated lipped channel short columns (of 600 mm length) subjected to monotonic axial compression. A total of 20specimens provided with circular perforation at the mid-height and at centre of the web, were tested by adopting different CFRP skin-strengthening configurations. Both uni-directional CFRP (CF_UD) and bi-directional CFRP (CF_BD) laminates were considered. The axial behaviour of the specimens was evaluated in terms of failure mode, peak axial strength and the axial load-deformation response. All the test specimens reported in this study failed due to local-distortional interactive buckling at the location of web perforation. A significant improvement in the axial capacity along with delayed failure was noted in certain CFRP strengthening configurations resulting in an enhanced structural performance. The structural response of specimens with different CFRP strengthening configurations was explained in detail. Finally, it was concluded that use of CF_UD and CF_ UD / BD were found to be more beneficial for the cases of single and double layer of CFRP respectively.