Behavior and calculation of tapered CFDST columns under eccentric compression

The tapered concrete-filled double skin steel tubular (CFDST) columns have been used in transmission towers with potential for other types of composite frame structures. However, the behavior of the tapered CFDST column under eccentric compression has not yet been studied, which will hinder the employment of such members. This paper reports an investigation on eccentrically loaded tapered CFDST columns with different load eccentricities. The numerical investigation was also carried out by using the finite element model to predict the behavior of the tapered member. Comparisons were made between the tapered and straight members on the strength and stress distribution. The stability of the tapered column was studied through numerical calculation. Finally, the load carrying capacity of the tapered CFDST column under eccentric compression was predicted using the concept of “equivalent column”.

► We provided new test data on tapered CFDST columns under eccentric compression.
► We investigated the stress and confinement effect of tapered CFDST column.
► We discussed the equivalent straight columns for tapered CFDST column.