Lean Duplex Stainless Steel Tubular Members Strengthened with CFRP Plate Subjected to Web Crippling

Abstract

Lean duplex stainless steel tubular members are relatively new grade of material. An experimental investigation of lean duplex stainless steel tubular members subjected to web crippling is presented in this paper. The test specimens were strengthened with adhesive bonded carbon fibre-reinforced polymer (CFRP). The web crippling tests were conducted under End-Two-Flange, Interior-Two-Flange, End-One-Flange and Interior-One-Flange loading conditions. A total of 38 web crippling tests was conducted. The investigation was mainly focused on the effects of web slenderness of lean duplex stainless steel tubular sections on CFRP strengthening against web crippling. The lean duplex stainless steel type EN 1.4162 was used in the investigation. The tests were performed on five different sizes of square and rectangular hollow sections that covered a wide range of web slenderness ratio from 8.1 to 57.0. Three different failure modes were observed in the tests of the strengthened specimens, namely the adhesion, interlaminar failure of CFRP plate and combination of adhesion and interlaminar failure of CFRP plate. It is shown that the web crippling strength of lean duplex stainless steel tubular members may increase up to 76% due to the strengthening of CFRP.