EXPERIMENTAL STUDY ON BEHAVIOR OF AXIALLY LOADED CONCRETE-FILLED STEEL TUBE STUB COLUMNS WITH LOCAL CORROSION

A total of 18 concrete-filled steel tube stub columns were designed and manufactured to experimentally investigate the effects of depth, size and location of local corrosion on axial compression behavior of CFST columns. The local corrosion defects were manufactured by machining combined with electrified accelerated corrosion. The test results show that within the range of corrosion parameters designed, the bearing capacity of CFST columns with a corrosion depth ratio more than 45% decreases sharply with the increasing of corrosion depth, suggesting the depth of corrosion defects influences the bearing capacity of CFST columns significantly; when the corrosion depth ratio is less than 45%, the circumferential and longitudinal dimensions of defects have negligible effect on the axial bearing capacity; moreover, the axial bearing capacity of specimens decreases with the local corrosion approaching to the mid-height of the column. A model was proposed to predict the axial bearing capacity of CFST columns with local corrosion based on the experimental results and theoretical analysis. The high accuracy of the proposed model was verified through a comparison with 100 collected CFST columns without or with local defects.