The Finite Element Analysis of Axial Compressive Behavior of Square CFST Columns with Multiple Localized Corrosions

Concrete filled steel tube can fully utilize the advantages of both steel and concrete, which is why it is widely used in high-rise buildings, airport stations, bridges, and other projects. However, during the long-term service life of CFST columns, corrosion is inevitably encountered. This paper uses finite element software to simulate the effects of multiple localized corrosion on square CFST columns. It analyzes the influence of various factors such as multiple localized corrosion depth, multiple localized corrosion shape, multiple localized corrosion circumferential position, and multiple localized corrosion axial height on the specimen's bearing capacity, stiffness, and ductility, revealing the degradation pattern of bearing capacity in square CFST with multiple localized corrosions. The research results show that as the depth of multiple localized corrosions increases, the bearing capacity of the specimen gradually decreases, and the rate of decrease accelerates. With the same corrosion area, the larger the axial length of the multiple localized corrosions, the greater its impact on the specimen's bearing capacity. As the angle of multiple localized corrosion increases, the specimen's bearing capacity first decreases and then increases. When two localized corrosions are on opposite sides, the weakening effect on bearing capacity is relatively small. When the two localized corrosions are adjacent to each other, the weakening effect on bearing capacity is more significant. When one corrosion is located at the midpoint of the column and the other at one-quarter of the column height, the specimen has the lowest bearing capacity, with a decrease of nearly 10% compared to the non-corroded specimen, and it is slightly lower than the specimen where the corrosion is uniformly located at the midpoint of the column height. When corrosion occurs at the bottom of the column, the weakening effect on bearing capacity is reduced due to the end effect.