Behavior of steel‐fiber‐reinforced concrete‐filled square steel tube stub columns under eccentric compression

Abstract

Concrete-filled square steel tube (CFSST) stub columns are vital to structural engineering owing to their excellent mechanical properties and architectural benefits.In this study, 42 steel-fiber-reinforced CFSST stub columns with different variables are designed to investigate their eccentric compression performance. The variables include the eccentricity ratio (0.08, 0.20, and 0.32), steel fiber volume content (0.0%, 0.6%, 1.2%, and 1.8%), concrete strength (40, 50, and 60 MPa), and square steel tube thickness (3, 3.75, and 4.5 mm). The failure mode, load-lateral deformation characteristics, load-bending moment interaction relationship, and relative load-strain response are investigated experimentally. It is discovered that the use of steel fibers can increase the bearing capacity and improve the ductility of CFSST stub columns. The ABAQUS software is applied to establish and calculate finite element models, and the results of which are consistent with the experimental results.Moreover, a simplified formula to calculate the eccentric ultimate bearing capacity of CFSST stub columns is derived. Under a certain safety margin, the predicted results agree well with the experimental results.