Behavior of square concrete-filled stainless steel tube columns after high-temperature sliding

Abstract

This paper presents herein pertains the experimental and numerical investigations on axial compressive behavior of square concrete-filled stainless steel tube (CFSST) columns after high-temperature sliding. A total of 117 CFSST specimens were tested under axial compression loading. The design variables included tube thickness, temperature, duration, and concrete compressive strength. Test results indicated that the initial stiffness of square CFSST short columns was degenerated due to high-temperature sliding. CFSST specimens exhibited a 62.7% lowest residual strength at 1000 °C. The influence of high-temperature duration on the residual strength of square CFSST short columns after high-temperature sliding was limited. The residual strength of specimens was positively correlated with the thickness and concrete strength. All square CFSST columns after high-temperature sliding experienced an outward local buckling under axial compression. Finite element models of square CFSST columns after high-temperature sliding are established and validated against the experimental results. In addition, the parameter formulae of residual strength for CFSST columns after high-temperature sliding were proposed, which achieved high accuracy. This research results could provide strengthening reference for the application of CFSST columns after high-temperature sliding.