Ferritic Stainless Steel Tubular Sections Strengthened with CFRP Plate subjected to Concentrated Interior Bearing Load

Abstract

Web crippling failure of ferritic stainless steel tubular structural members could be found due to localized concentrated loads or reactions. This paper reports an experimental investigation on strengthening of ferritic stainless steel tubular 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 ferritic stainless steel square and rectangular hollow sections subjected to web crippling was conducted. The web crippling tests were conducted under two loading conditions of Interior-Two-Flange (ITF) and Interior-One-Flange (IOF). A total of 18 web crippling tests was conducted in this study. The investigation was mainly focused on the effects of web slenderness of ferritic stainless steel tubular sections on CFRP strengthening against web crippling. The tests were performed on five different sizes of square and rectangular hollow sections. The ferritic stainless steel type EN 1.4003 test specimens were used in this study. Tensile coupon tests were conducted to determine the material properties of the ferritic stainless steel specimens. Most of the strengthened specimens were failed by debonding of CFRP plate from the ferritic stainless steel tubes. 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. The failure loads, failure modes and the load-web deformation behaviour of the ferritic stainless steel sections are also presented.