Behaviour and design of stainless steel-concrete composite beam-to-column joints

Abstract Stainless steel is considered a promising construction material for steel and composite structures owing to a number of superior features concerning excellent durability, high ductility and aesthetic benefits. Over the past few decades, a great deal of research has investigated the behaviour and design of stainless steel structural members. However, there is still very limited knowledge on the behaviour of joints between stainless steel/composite beams and columns. This paper presents for the first time, an experimental study on the structural behaviour of stainless steel-concrete composite (SSCC) beam-to-column joints, highlighting the “all stainless steel” concept (including stainless steel sections, bolts, reinforcing bars and shear connectors) to ensure a consistent service life within the entire structural system. Two types of stainless steels are incorporated in this study, namely austenitic and lean duplex. In addition to the experiments, 3D finite element models are established and validated against the test results in order to perform further parametric study. Based on the experiments and numerical analyses, the key structural characteristics of SSCC joints are evaluated and compared with the design predictions by Eurocode 3/4 and AS/NZS 2327. It is concluded that the existing design method (initially developed for carbon steel composite joints) cannot be directly applied for SSCC joints considering the unique material characteristics of stainless steel, i.e. the nonlinear stress-strain behaviour and immediate strain-hardening after yielding. Modifications to the existing method is therefore proposed for design of SSCC joints.