Analytical behaviour and design of square CFDST subjected to local bearing force

Abstract

This paper presents a finite element analysis (FEA) model for the behaviour of square concrete filled double skin steel tube (CFDST) under local bearing force. Feasibility of the developed FEA model was validated extensively against available experimental results. The predicted results obtained from the FEA modelling were found to match well with those observed from the tests in terms of failure patterns, load versus deformation curves and bearing capacities. The full-range load-transferring mechanism of square CFDST under local bearing force was then analyzed using the FEA model. Comprehensive parametric studies were also carried out to investigate the effect of various parameters on the bearing capacity of square CFDST subjected to local bearing force. The evaluated parameters mainly included the hollow ratio of CFDST, geometric configuration of the bearing member (BM) and the CFDST, the width to thickness ratio of steel tubes, and the strengths of steel and concrete materials. Based on the parametric analysis results, simplified design formulae were proposed for calculating the bearing capacity of square CFDST under local bearing force. Validated through the reported experimental data, the proposed formulae were featured with a reasonable accuracy and could be adopted in the practical design of square CFDST members subjected to local bearing force.