Simplified nonlinear analysis of steel-concrete composite frames

Some current specifications, such as AS4100 and AISC360-10, permit the design of steel frames by advanced analysis (second-order nonlinear inelastic analysis). But this is not the case for the design of steel-concrete composite frames, and the relevant research is still in its infancy despite widespread application of such frames in modern construction. To conduct advanced analysis of composite frames, the best option is to adopt simplified numerical models because of the computational efficiency and ease in the development of such models. In this paper, simplified numerical models, which are suitable for conducting advanced analysis, are developed for composite frames with concrete-filled steel tubular columns, composite beams, and composite connections. The results obtained from the simplified modelling of composite frames agree well with test data reported in the literature. Finally, a comparative study between traditional member-based design and design by advanced analysis of composite frames is presented. The comparative study indicates that the design based on advanced analysis is more economical compared to the design using the traditional member-based method.