Effect of Nonlinear Buckling Failure Investigation on Shells

Abstract

The Hollow Section (HS) is a relatively new shape of high strength, hot-rolled steel sections. It is being used in structural building applications due to its unique asthetics. The cut-out not only introduces stress concentration but also significantly reduces buckling load. Concrete-filled steel tubes have been widely used in high rise composite buildings, bridges and offshore structures owing to their excellent performance, such as high strength, high ductility, large energy absorption capacity and low costs. A CFST is constructed by filling either normal or high strength concrete into a normal or high strength hollow steel tube. Concrete with compressive strength above 50MPa is considered as high strength concrete while structural steels with yield strength above 460MPa are treated as high strength steels. The in-filled concrete effectively prevents the inward local buckling of the steel tube so that the steel tube walls can only buckle locally outward. This paper deals with influence of stiffeners, different grades of concrete, different cutouts on shells. Stiffeners are secondary plates or sections which are attached to beam webs or flanges to stiffen them against out of plane deformations.Almost all main bridge beams will have stiffeners. However, most will only have transverse web stiffeners, i.e., vertical stiffeners attached to the web. Deep beams sometimes also have longitudinal web stiffeners.