Effect of friction on axially loaded stub circular tubed columns

Abstract

This article discusses the influence of bond and friction between the steel tube and concrete on composite response for circular tubed-reinforced-concrete short columns under axial compression. Thirteen large diameter-to-thickness ratio (D/t = 133,160) circular tubed stub columns with different types of the steel tubes (galvanized or not) and five reinforced concrete counterparts were tested. Although circular tubed-reinforced concrete specimens were characterized by the shear failure mode, the ductility performance was much better than the reinforced concrete specimens. A simplified theoretical model and a three-dimensional finite element analysis model were developed to analyze the bond and friction behavior of circular tubed-reinforced-concrete columns. The stress state of the steel tubes is determined by the friction coefficient because slipping occurred between the tube and its in-filled concrete. The formulas considering friction coefficient are also proposed for the prediction of the axial loading resistances of circular tubed concrete stub columns. The predicted results are in good agreement with the experiment results and nonlinear finite element analysis results.