The Ultimate Strength of the Concrete-Filled Tubular (CFT) Section Columns

초록

This paper describes design strength of concrete-filled tubular (CFT) section columns accounting for local buckling of steel skin. The local buckling has a negative effect on the ultimate compression strength based on the yield stress of steel skin and nominal compressive strength of in-filled concrete. A squash load formula for CFT stub columns is proposed to account for the post-local-buckling strength of steel skin. A compressive strength formula for filled-in concrete accounting for the confining effect of steel skin and strength ratio between filled-in concrete and steel skin is also proposed. The squash loads predicted by the proposed strength formula for the direct strength method were compared with the AISC (2010) and Eurocode4 (2004). The comparison showed that the squash load formula proposed can predict conservatively the squash load of circular and rectangular CFT columns with local buckling.

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