ORTHOGONAL EXPERIMENTAL STUDY ON AXIAL MECHANICAL BEHAVIOR OF LOCALLY CORRODED CIRCULAR STEEL TUBES

The effects of parameters such as circumferential corrosion ratio, axial corrosion ratio and corrosion time on the axial mechanical behavior of slender circular steel tubular columns with localized corrosion in offshore atmospheric environment were studied. This was conducted by using a three-factor and three-level orthogonal test. A formula for the axial compressive carrying capacity of the specimens with localized corrosion was proposed according to the test results. The results indicate that the failure modes of the specimens did not change, and all failure modes were associated with the extreme point instability. The stiffness of the specimens with similar corrosion time did not change significantly. However, the carrying capacity varied greatly among the localized corrosion modes. The influence of corrosion time, circumferential corrosion ratio and axial corrosion ratio on the degradation of stiffness and carrying capacity of the specimens decreased successively. The least favorable localized corrosion mode for the carrying capacity degradation of the specimens was H3L3-270, of which the average carrying capacity degradation due to the corresponding factors were 19.30%, 18.47% and 22.24%, respectively. However, the least favorable localized corrosion mode for the stiffness degradation of the specimens was H1L3-270, of which the average stiffness degradation due to the corresponding factors were 13.53%, 13.38% and 15.22%, respectively. The carrying capacities predicted by the proposed formula were close to the test results, and had a certain safety margin.