Static performance of steel slag concrete filled steel square hollow section members

Abstract

The performance of steel slag concrete (SSC) filled steel square hollow section (SHS) stub columns and beams under short-term static loading is experimentally and numerically studied in this paper. Fifteen typical specimens, including 10 stub columns and 5 beams, were tested. The main factors investigated are: mass substitution rate of steel slag aggregate (SSA) [Rc(f)], which is equal to mass of steel slag coarse (fine) aggregate over that of total coarse (fine) aggregate, and tube width-to-thickness ratio (B/t). The failure modes, relationship between loads and deformations, axial/flexural capacity and axial compressive/flexural stiffness were recorded and analysed. The test results indicate that, the SSC filled steel SHS specimens have similar static performance as the reference composite specimens using ordinary concrete (OC). The variation in the mass substitution rate of SSA mainly leads to the difference in the mechanical factors, and simultaneously the behaviour of stub columns with a smaller B/t is better than that of the corresponding specimens with a larger B/t. A modified compressive stress-strain model of the SSC with the effect of Rc and/or Rf was developed, and finite element (FE) models were further established to investigate the static performance of the SSC filled steel SHS stub columns and beams. The FE models were validated by the experimental results in this study and the existing literature. Finally, the suitable method for the axial/flexural capacity prediction of the SSC filled steel SHS members was recommended.