Load-bearing capacity of axially loaded circular concrete-filled steel tubular columns

Concrete-filled steel tube structures have experienced rapid development in recent decades. Simplified methods have been proposed in design codes, such as BS EN 1994-1-1:2004 (Eurocode 4), Mander and co-workers, as well as Lu and Zhao, have proposed a simplified model to determine the load-bearing capacity of concrete-filled steel tubular columns. This paper presents an analysis of the test results of 311 specimens of axially loaded, concrete-filled steel tube circular columns available from the literature with length/diameter (L) ratio greater than 4. The test results are compared with international design codes and equations. A comparative study of the variable parameters such as concrete compressive strength, yield strength of steel and diameter/thickness (D) ratio is also presented. Their influence on the estimation of ultimate load capacity of concrete-filled steel tube columns and their impact on the proposed design codes and theoretical equations are analysed.