The Squash Load of Concrete-Filled Tubular Sections

This paper describes the squash load of concrete-filled tubular (CFT) section columns with or without local buckling based on the compression test results. Local buckling of non-compact and slender steel sections is accounted for in the limiting stress formula specified for the steel skin of CFT columns in a similar manner to the AISC specifications. Simple squash load formulae for CFT stub columns for the direct strength method have been proposed to account for post local buckling strength of slender steel skin and enhanced concrete compressive strength due to the confining effect by the steel skin. The squash loads predicted by the proposed strength formula were compared with available test results and those predicted by the AISC specifications and Eurocode4. The comparison confirmed that the squash load formula proposed could predict the squash load of CFT columns conservatively.