Behaviour of octagonal steel-reinforced concrete box columns under compressive load

A series of tests on octagonal steel-reinforced concrete box stub columns and columns under compressive load was carried out. Material properties of the concrete, inner octagonal steel tube and reinforcement bars used in the test specimens were measured. The effects of wall thickness of inner octagonal steel tubes and eccentric distance of compressive load on the performance of octagonal steel-reinforced concrete box columns were discussed. Based on test results, a finite-element model was developed using Abaqus to simulate the experimental studies. The full stages of the behaviour of the octagonal steel-reinforced concrete box stub columns and columns were investigated. Finally, design equations for the octagonal steel tube-reinforced concrete box stub columns and columns under compressive load were proposed. The measured strengths of the tested specimens were compared with the design strengths calculated using the proposed method given in this paper.