Use of Stainless Steel as Structural Members in Bridge Construction and Fibre Reinforced Polymer Strengthening

Abstract

Stainless steels are increasingly used as a structural member in bridge construction due to its exceptional and attractive features in terms of durability, high strength, superior corrosion resistance etc. Over the last few years, stainless steel has been playing an important role in the construction of bridges, because of their combination of high strength and corrosion resistance. Structural uses of stainless steel in bridges and several recent examples of using stainless steels in bridge construction are presented in this study. The webs of cold-formed stainless steel members in bridge construction may cripple due to concentrated bearing load in the absence of stiffeners. However, the web crippling strength can be enhanced by Fibre Reinforced Polymer (FRP) strengthening in the web of the sections. This paper presents an extensive experimental and numerical investigation of FRP strengthening lean duplex stainless steel hollow sections subjected to web crippling. The investigation was focused on the effects of surface treatment, web slenderness, different adhesives and FRPs for the strengthening. The lean duplex stainless steel type EN 1.4162 was used in the investigation. A series of laboratory tests was performed on five different sizes of square and rectangular hollow sections that covered a wide range of web slenderness ratio from 8.2 to 56.2. The failure loads, failure modes, enhancement of load carrying capacity for FRP strengthening and the load-web deformation behaviour of lean duplex stainless steel sections are presented in this study. This study is also focused on the nonlinear finite element analysis using the program ABAQUS. The numerical results were verified against the test results. It is shown that the strengths of lean duplex stainless steel hollow sections may increase up to 76% due to the strengthening of FRP.