Strength of compressed concrete filled steel tube elements of circular and square cross- section

Abstract

The purpose of the research is to determine the values of compressive force eccentricities at which the strength of square-sectioned compressed concrete filled steel tube elements (CCSTEs) is not lower than that of circular-sectioned elements that are similar in materials consumption. Strength calculations are carried out using a specially developed "CFST" computer program. The reliability of calculations, obtained with this program, is pre- verified basing on the calculation data, related to 203 circular-sectioned CCSTEs and 264 square-sectioned elements. The results of the calculations demonstrate that, given eccentric compression, where eccentricities are slightly outside the bounds of the core of section, the CCSTE strength criterion should not significantly influence the selection of their geometric shape. Based on this criterion, when relative eccentricities exceed 0.2-0.25, the preference should be given to the elements with a square cross-section. Moreover, the area of rational use of square-sectioned CCSTEs is extended with the increase in structural flexibility.