## 1 Introduction
In terms of the influence of stirrup corrosion on the mechanical performance of concrete columns, [PERSON] [19] and [PERSON] [20] studied the compression and buckling behavior of longitudinal reinforcing steel bars after stirrup corrosion, finding that the buckling of longitudinal reinforcing steel bars was also an important reason for the reduction of bearing capacity. [PERSON] et al. [21; 22] conducted experimental research on the uniaxial compression of corroded concrete columns with stirrups and proposed a constitutive model of bearing capacity, but the model did not consider the influence of concrete section damage and buckling of longitudinal reinforcing steel bars. [PERSON] [23], [PERSON] [24], and others have studied the mechanism of bearing capacity degradation of stirrup-corroded concrete columns, showing that the restraint effect of stirrups can improve the bearing capacity of concrete in the core area and that the restraint effect weakens with increasing stirrup corrosion rate. The cracks and section damage of concrete cover caused by stirrup corrosion are the main reasons for the decline in bearing capacity. It should be noted that the influence of corroded stirrups on column bearing capacity was considered in the above study, but the influence of load was not considered. In practical engineering, reinforcing steel bar corrosion occurs when concrete columns are subjected to loads. The combined action of load and corrosion may accelerate the deterioration of structural properties. In addition, the existing research has found that the corrosion degree of stirrups is more serious than that of longitudinal reinforcing steel bars [25; 26], especially, stirrups at the junction with longitudinal reinforcing steel bars may even be corroded and broken. The concrete cover of stirrups is thinner than that of longitudinal reinforcing steel bars, thus they are more likely to be corroded. When stirrups are corroded, the decreased mechanical properties, reduced bond strength with concrete, and cracking of concrete cover will reduce the constraints of the stirrup on the concrete and longitudinal reinforcing steel bars in the core area, thus reducing the mechanical properties of the concrete column. Therefore, it is very important to research the degradation of the mechanical properties of concrete columns after stirrup corrosion. Considering the coupling effect of axial load and chloride, this paper conductedan experimental study investigating accelerated corrosion and bearing capacity of axial compression concrete short columns and analyzed the distribution of corrosion-induced cracks, the development process of cracks, the decay law of mechanical properties, and the mechanism of failure of stirrup-corroded columns under axial load. On this basis, the damage degree parameter was introduced to fully consider the concrete section damage caused by corroded stirrups and buckling characteristics of longitudinal bars under compression and the bearing capacity prediction model of axial compression concrete columns with corroded stirrups was established, providing a reference for the durability evaluation of concrete structures in service in chloride environments.