# An Assessment of the Structural Performance of
## 3 Test Results and Discussion
### Test Results under Monotonic Loading  
The evaluation test results of the structural capacity of the RC beam specimens under monotonic loading, according to the corrosion rate of the rebar, are shown in Figure 6. Overall, as the corrosion rate of the rebar increased, the structural capacity of the beam specimens tended to decrease. The deflection values at the yield and maximum load do not provide any meaningful significance. Particularly, in the case of the rebar corrosion of the entire area, the structural capacity was significantly impaired due to the corrosion of the rebar. For specimens A-1-1 and A-2-1, it was observed that both the yield load and maximum load were substantially reduced to a range between 14.5-17.7% and 12.3-16.1%, respectively. Furthermore, specimen A-3-1 showed a dramatic reduction of 40.1% in yield load and 35.2% in maximum load. In the case of localized corrosion in the constant moment area, the reduction in the yield load was reduced to 12.9-24.3%, which is a similar extent to the specimens with the entire area corrosion. And the reduction in the structural capacity at the maximum load, at the same corrosion rate, was less pronounced in the range of 3.0-17.6%. For localized corrosion in the constant shear area, the reduction in the structural capacity was insignificant compared to the entire area corrosion and the constant moment area corrosion cases. The yield load and maximum load were reduced by 0.5-16.0% and 5.6-9.9%, respectively. However, specimen S-1-1 resulted in an increase of 5.9% in the yield load and 0.3% in the maximum load. Under a monotonic load, the yield load and maximum load of the RC beam specimens, considering the corrosion of the rebar, are presented in Figure 7. Generally, an increasing corrosion rate resulted in a decrease in the structural capacity. However, it was found that localized corrosion in the constant shear area did not significantly affect the structural capacity up to an average corrosion rate of 15%. As described in the experimental program, the average target levels of corrosion were 5%, 10%, and 30% of the weight loss ratio. Subsequently, the corrosion weight loss (%) of the rebars was measured after the tests were completed. Figure 8 presents the localized average weight loss rates of the tensile reinforcement and stirrups in the monotonically loaded beam specimens after the tests were completed. Overall, it was observed that an increase in the average corrosion rate of the reinforcements resulted in a significant decrease in the load-carrying capacity of the beam specimens. In the case of the rebar corrosion of the entire area, specimen A-2-1 resulted in a slightly higher average corrosion rate from the longitudinal rebar B, compared to specimen A-1-1. An additional average weight loss of 3.8% led to a 4.3% reduction in maximum load capacity. In the case of localized corrosion in the constant moment area, the average corrosion rates from specimens B-1-1 and B-2-1 were  
Figure 6: Deflection of beam versus applied monotonic load. (**a**) corrosion in entire area; (**b**) partial corrosion in mid area; (**c**) partial corrosion in end area. nearly identical, and an average weight loss difference of 1.2% caused a 3.0% reduction in the maximum load capacity. For localized corrosion in the constant shear area, the average corrosion rate increased in the order of S-3-1 > S-2-1 > S-1-1. The stirrups in specimen S-3-1 were significantly more corroded and had the lowest maximum load capacity. Figure 8: Corrosion weight loss of rebars measured at 100 mm intervals along the longitudinal direction under the monotonic loading condition. Figure 7: Corrosion weight loss (%) versus yield and ultimate loads under monotonic loading condition. Figure 9 illustrates the crack patterns in the concrete cover and the occurrence of cracks with the corroded rebars due to the imposed monotonic loads on the beam specimens.