## 5 Conclusions  
1. The load has a certain influence on the direction, width, and pattern of cracks in stirrup-corroded columns. The corrosion-induced cracks mainly developed along the direction of the longitudinal reinforcing steel bars (cracks along longitudinal reinforcing steel bars caused by corrosion) under the coupling effect of axial load and chloride, and there were almost no transverse corrosion-induced cracks along the corroded stirrups. When the stirrup corrosion rate was low, the corrosion-induced cracks mainly appeared on one side, while the corrosion-induced cracks mainly appeared on  
Figure 14: The flexural mode of longitudinal reinforcing steel bars. (a) 1 st order flexure mode. (b) 2 nd order flexure mode. (c) 3 rd order flexure mode. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Specimen** & **Stirrup Corrosion** & **Results of the** & **Results of the** & **Model/Test** \\
**Number** & **Rate (\%)** & **Model (kN)** & **Test (kN)** & **Model/Test** \\ \hline GZ1 & 0.00 & 1373 & 1500 & 0.9153 \\ GZ2 & 4.32 & 1088 & 1100 & 0.9891 \\ GZ3 & 10.82 & 936 & 950 & 0.9852 \\ GZ4 & 14.19 & 894 & 900 & 0.9933 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Comparison between model results and experimental results. both sides when the stirrup corrosion rate was high. The length and maximum width of corrosion-induced cracks increased as the stirrup corrosion rate increased, but the average width of the corrosion-induced cracks did not change significantly. 2. After the stirrup-corroded column reached the ultimate load, the concrete cover spalled off in pieces along the corrosion-induced cracks and loading cracks and the core concrete was crushed. The brittle property of the stirrup-corroded columns was more obvious than that of the uncorroded column, the tensile deformation of the stirrup was serious, and the flexure length of the longitudinal reinforcing steel bars spanned more than one stirrup, so the strength of the longitudinal reinforcing steel bar could not be fully utilized. 3. When the stirrup-corroded column was stressed, the circumferential deformation increased with the increasing degree of stirrup corrosion. The corners of the stirrup were easily pulled apart, which reduced the constraint ability of the core concrete and main reinforcing steel bars. 4. With the increasing corrosion rate of the stirrups, the ultimate bearing capacity of the column decreased, and the decline in the bearing capacity at the early stage was greater than that at the later stage. With the increasing stirrup corrosion rate, the slope of the load-longitudinal displacement (\(N\)-\(\Delta\)) curve decreased, meaning the stiffness of the column decreased. 5. Considering the column section damage caused by stirrup corrosion, the reduction of the lateral constraint effect of the corroded stirrup on the longitudinal reinforcing steel bars and the flexure of the longitudinal bars, a prediction model of the ultimate bearing capacity of the short column with corroded stirrups under axial compression was established by introducing the bearing capacity attenuation coefficient \(K_{\text{ c}}\) and damage degree \(\lambda_{\text{ c}}\). The calculated values of the model were in good agreement with the measured values. In practical application, the bearing capacity attenuation coefficient and the damage degree can be calculated according to the corrosion-induced cracking area of the component surface measured on site, which can predict the residual bearing capacity of stirrup-corroded columns and provide a theoretical basis for structural durability design and assessment. 6. The degradation of bearing capacity of stirrup-corroded columns is related not only to the degree of damage of the column section but also to the restraint effect of the corroded stirrup. Stirrups with different degrees of corrosion have different circumferential strains and restraint effects under axial pressure.