Investigations on stainless steel T- and Y-joints in cold-rolled circular hollow sections

Abstract

With the wide applications of stainless steel structures, stainless steel joints in cold-rolled tubes are increasingly used in building structures. However, the behaviors and the design methods of tubular joints were rarely studied. This study conducted experimental and numerical investigations on austenitic stainless steel T- and Y-joints in cold-rolled circular hollow sections with axial compression in brace. A total of six T-joints and three Y-joints were tested. The effects of the geometric configurations and the preload in the chord on the behaviors of the joint were considered. The material properties, failure modes, joint strengths and load-deformation curves were all reported. Test results showed that the failure mode of T-joints was the plastification failure of the chord on the chord face as well as the chord side wall. The failure mode of Y-joints was similar to that of T-joints while the deformation mainly occurred on the side of chord face with an obtuse angle to brace. Comparisons of the predictions using the CIDECT recommendations and the tests results indicated that the predictions were conservative. Finite element models were developed and validated using the test results. A total of 192 finite element models were analyzed to evaluate the effect of geometric properties and the chord preload on the joint strength. The functions of Qu and Qf in CIDECT for the chord plastification failure were modified based on the parametric analysis results. Comparisons of the predictions and the test results show that the proposed modified equations had a good accuracy.