Assessment of Stainless Steel Tubular T-joints Under Chord Sidewall Failure Mode by a Semi-analytical Formulation

There are numerous benefits of tubular profiles that make them increasingly used in civil engineering. At the same time, stainless steel is a material with excellent properties and high corrosion resistance. However, stainless steel's high initial material cost has limited its use primarily to specialist and prestige applications, which makes it necessary to develop more accurate design rules for this material. When tubular profiles are used, it is necessary to assess the joint strengths, considering that they can fail by different mechanisms. The present work aims to develop a semi-analytical formulation to predict stainless steel tubular T-joint resistances. Joints with the brace-to-chord width ratio equal to 1 were considered in this study; therefore, the failure occurs in the chord sidewall. To assess the sidewall instability critical load, the exact stress fields were determined using Mathieu's theory, and then the Ritz energy method was applied. Considering that the joints are made of stainless steel, the next step is to transform the load found from linear to the non-linear regime. For that, a new formulation based on Ramberg-Osgood equations was developed. Finally, the results obtained from the proposed method were compared with the experimental results obtained by Feng and Young (2008) and the results from the main current standards and literature. It was observed that the proposed method presented satisfactory results, while the predictions from design codes were, in general, very conservative. © 2022 Ernst & Sohn GmbH.