Concrete-filled circular stainless-steel tubular columns subjected to low-temperature axial compression

This paper studied the compression behaviours of concrete-filled circular stainless-steel (SS) tubes (CFSSTs) used in the cold-region engineering constructions. Sixteen CFSSTs using SS 30408 tubes were firstly tested at varying low temperatures (T = 20, -30, -60, and -80 degrees C) related to the cold-region environments. The studied parameters in the testing programme are low temperatures (T) and wall-thickness of SS tube (t). Subjected to lowtemperature compression, all CFSSTs failed in outward local buckling of SS tube and crushing of concrete. Most of the CFSSTs exhibits ductile compression behaviour without declining recession due to the excellent ductility of SS tube. The P-Delta curves of CFSSTs exhibit a linear elastic stage, a relative short nonlinear stage, and a long strength-hardening stage. The decreasing low temperature and increasing wall-thickness of SS tube significantly improved the compression behaviours of CFSSTs. The infilled concrete greatly improved the compression capacity and prevented inward local buckling of SS tubes in CFSSTs. This paper also developed finite element model (FEM) for compression-behaviour simulations of CFSSTs at low temperatures. Validations against 16 tests confirmed the FEM simulation accuracy. Different code prediction equations in AISC360, Eurocode 4, and AIJ were checked for predicting the ultimate compression capacity of CFSSTs at low temperatures. Finally, Eurocode 4 and AIJ were recommended after comparisons of predictions with test results.