Behaviour of concrete-filled thin-walled corrugated steel tubes under cyclic axial compression

Concrete-filled thin-walled galvanized corrugated steel tube (CFCST) is a novel composite member with great potential to be used in harsh and corrosive environments as an outdoor pier or an underground structural column, etc. To properly understand the stress–strain performance of such column, this paper presents an experimental investigation on the stress–strain responses of 15 CFCST stub columns subjected to cyclic axial compression. The main variables are diameter-to-thickness ratios of corrugated steel tubes, loading patterns, and unloading/reloading cycles. The test results show that the thin-walled corrugated steel tube can enhance the axial strength and ductility of core concrete significantly. The failure modes, work mechanisms, axial stress–strain responses, plastic strains, and stress deteriorations are examined and addressed in detail. Two existing models, one for monotonic loading and the other for cyclic loading, are employed for comparison. The results show that modifications should be made for better applicability.