Axial compression behaviors of square steel tubes at low temperatures

Abstract

This paper investigated the compression behaviors of square steel tube (SST) columns used in cold-region engineering structures. Twenty-eight SST columns were tested at low temperatures of 20, −30, −60, and − 80 °C. The studied parameters were low temperature (T) and slenderness ratio (λ) of SSTs. Under low-temperature compression, stub columns (λ = 5) failed in local buckling whilst slender columns (λ = 15 and 25) failed in global buckling. Low temperatures exhibited marginal effects on failure modes, and slightly improved (less than 12 %) the ultimate compressive resistance (Pu) of SSTs. Decreasing T and λ values increased the compressive resistance of SSTs. Finite element (FE) models were established to simulate compression behaviors of SSTs at low temperatures, with accuracy confirmed by 28 test results. The FE parametric studies indicated that decreasing the width-to-thickness ratio of SSTs generally improved their compression capacity and ductility. Moreover, different code prediction formulae in GB50017, AISC 360–16, and Eurocode 3 for SSTs were checked to predict the Pu. Finally, prediction equations were developed to predict the compression resistance of SSTs at low temperatures. The prediction equations provided reasonable estimations on Pu with an average discrepancy of 4 %.