Compressive strength of circular concrete-filled double skin tubular short columns

• FE models are developed for circular concrete-filled double skin short columns.
• The accuracy of the models is established by comparisons with experimental results.
• Parametric studies on the behaviour of the axially loaded CFDST columns are conducted.
• The results are used to examine the accuracy of various design codes and models.
• A new formula is proposed providing a more accurate and less scattered prediction.

This paper focuses on the compressive strength of the concrete-filled double skin steel tubular (CFDST) short columns. Columns with external and internal circular carbon steel tubes are merely considered. First, this paper summarises previously developed formulas for predicting the compressive strength of the CFDST columns, along with the formula recently suggested by Yu et al. (2013) for solid and hollow circular concrete-filled tubular (CFST) columns. The various formulas for predicting compressive strength are then compared with test results. Test results are then organised and evaluated according to the relevant test specimen parameter; the diameter-to-thickness ratio (D/teD/te). It is found that the available tests do not cover the full range of the D/teD/te ratio. Hence, numerical nonlinear simulations, based on the finite element (FE) method using the software package ABAQUS/Standard, are constructed to compensate for the shortage in the available results. Through comparison with test and FE results, a new design formula is suggested. Such formula is shown to be more accurate than available formulas for estimating the compressive strength of the CFDST short columns. This recommended design model requires relatively less calculation efforts, and provides less scattered predictions than those using the current design rules. At the end, an illustrative example for the calculation of the compressive strength of the CFDST columns using the currently proposed formula is provided.