Web Crippling Test of Cold Formed Steel Channels Using CFRP under Various Load Cases

Web crippling failure of cold formed steel channel members could be found due to localized concentrated loads or reactions. This paper reports experimental and numerical investigation on strengthening cold formed steel channel members using externally bonded high modulus carbon fibre-reinforced polymer (CFRP) plate. The CFRP plate strengthening is only applied to a small localize area subjected to concentrated load. A series of tests on CFRP strengthened cold formed steel channel members sections subjected to web crippling was conducted. The web crippling tests were conducted under four loading conditions of end-two-flange (ETF), interior-two-flange (ITF), end-one-flange (EOF) and interior-one flange (IOF). The investigation was mainly focused on the effects of web slenderness of cold formed steel channel sections on CFRP strengthening against web crippling. Most of the strengthened specimens were failed by deboning of CFRP plate from the cold formed steel channel section. Two different failure modes were observed in the tests of the strengthened specimens, namely the adhesion failure as well as the combination of adhesion and cohesion failure. Finite element models have been developed and verified against the test results. The failure loads, failure modes and the load-web deformation behaviour of the cold formed steel channel sections are also presented. The experimental results are also verified with finite element analysis using ABAQUS software. The analytical results obtained are in good agreement with the experimental results.