Axial compression behavior of stub square concrete-filled steel tubes with regional defect

Abstract

This paper investigated the axial compression behavior of stub square concrete-filled steel tubes with simulated local corrosion damage through a series of tests. The local corrosion damage was simulated by machining a regional defect on the tube. Aiming at the test specimens, the noteworthy observations were recorded, the load-shortening curves were developed, and the influence of the defect dimensions on the compressive performance of the specimens was discussed. The results revealed that the local defect on the steel tube can lead to the loss of confinement on the core concrete and the centroid offset of the specimen. Therefore, the increase in the defect sizes decreased the ultimate resistance of the specimen. When the local defect sizes reached 150 mm (length) × 112.5 mm (width) × 3.5 mm (depth), the ultimate resistance and the ductility of the specimen decreased to 88.2 % and 65.8 % of the intact specimens, respectively. Furthermore, based on the experimental study and the theoretical analysis, with consideration of the cross-sectional area loss and the confinement loss, a method was proposed to predict the ultimate resistance of the specimens with the local defect, which also can be adopted to evaluate the residual resistance of the locally corroded members in service.