Low-temperature compression behaviour of square CFST columns using Q960 ultra-high strength steel

Abstract

This paper studied the low-temperature compression behaviours of concrete-filled Q960 ultra-high-strength-steel (UHSS) tubes (CFUT), which were developed for the high-performance Arctic engineering constructions. Fifteen stub CFUTs were tested at different low temperatures of 20, −30, −60, and −290 °C. The studied parameters in the testing program were low temperatures and thickness of Q960 UHSS tube. The low-temperature compression tests showed that the CFUTs failed in concrete crushing, outward local buckling and weld fracture at the corner of Q960 square UHSS tube. The Arctic low temperatures increased the compression capacity and stiffness, but reduced the ductility of CFUTs with Q960 UHSS tube. A 3D nonlinear finite element model (FEM) was built for simulations on the low-temperature compression behaviour of CFUTs with Q960 UHSS tube. Moreover, theoretical models on simulating load-shortening behaviours of CFUTs with Q960 UHSS tube at low temperatures were developed. Validations proved that the developed FEM and theoretical models predicted well compression behaviour of CFUTs with Q960 UHSS tube at low temperatures.