Structural behavior and strength of randomly pitted steel T-joints with circular hollow sections

This paper proposes a numerical modeling method to construct finite element models of randomly pitted steel Circular Hollow Section (CHS) T-joints. A series of parametric analyses were conducted on joints under axial brace compression to study the effect of geometric properties, such as the brace-to-chord diameter ratio, β, and chord diameter-to-thickness ratio, 2γ, on the ultimate strength under varying degrees of volume loss of corroded material (DOV). The synergy of key geometric properties and corrosion damage was clarified. The results indicated that the joints with a smaller β or a larger 2γ exhibited a larger reduction in ultimate strength under the same DOV. Moreover, due to the stress concentration stemming from irregular corrosion pits, the ultimate strength of a randomly pitted joint was nearly 10% lower than that with general corrosion. In particular, a significant variation in the ultimate strength of a randomly pitted joint was observed under a certain DOV, following a normal distribution. A correction factor was proposed to account for the impact of pitting corrosion on ultimate strength. This factor was then utilized to modify the CIDECT mean strength equation, leading to high accuracy in predicting the ultimate strength, with mean relative errors of less than 5%.