Experimental and numerical studies on the axial compressive performance of localized corroded circular steel tubes

The corrosion issue of steel structures is becoming increasingly prominent, and the study of the axial compressive performance of localized circular steel tubes (LCCSTs) is crucial for evaluating the safety of large-span steel structures. In this work, the electrochemically accelerated corrosion method is employed to simulate the localized corrosion of circular steel tube (CST) members, and the relative corrosion depth of the corrosion region is found to follow a normal distribution with a coefficient of variation of 0.44 through three-dimensional morphological scanning. Furthermore, the effects of different parameters on the failure modes and axial compressive performance of the CST members are investigated through experiments. The uncorroded members are characterized mainly by overall buckling, whereas the corroded members exhibit local buckling. In addition, the ultimate load capacity decreases by at least 30.7 % when the corrosion ratio increases from 15 % to 30 % and by a maximum of 6.3 % when the circumferential corrosion ratio increases from 0.5 to 1.0. Next, a refined finite element (FE) model of the LCCST members is developed. A comparison with the test results shows that the developed refined FE model can better simulate the failure modes and axial compressive performance of LCCST members. Parametric analyses based on the validated FE model are conducted, and the results reveal that the slenderness ratio, corrosion ratio, and circumferential and longitudinal corrosion ratios significantly affect the load capacity degradation coefficient of the members. Finally, based on the test and FE results, a formula for calculating the axial compressive load capacity while considering the effect of localized corrosion is established, and the comparison results reveal that most of the errors between the predicted values and the FE and test values do not exceed 10 %. Furthermore, 65 previous experimental data points of LCCSTs are collected, and the comparison reveals that the errors between the predicted values and the previous test results are mostly controlled within 20 %, which further verifies the accuracy and applicability of the formula for calculating the axial compressive load capacity of LCCST members.