## 5 Results  
### Cyclic Pushover  
In this study, the effects of pitting and uniform corrosion of longitudinal and hoop circular bars on the cyclic behavior of a bridge pier reinforced with steel plates of different thicknesses were investigated through cyclic pushover analysis. Figure 2 shows the force-displacement curves for bridge piers with different pitting corrosion ratios: (a) 0 and (b) 5% corrosion. Figure 2 clearly shows that the corrosion of the steel bars significantly reduces the ultimate capacity of the bridge pier. For example, the peak force for the pristine bridge pier was 1321.8 kN, and that of the bridge pier with a 5% corrosion ratio was 1257.7 kN, which represents a decrease of approximately 4.8%. For other corrosion levels, the hysteretic curves could also be calculated by applying the same procedure. Steel plates were used to strengthen the corroded bridge pier, and hysteretic curves of the bridge pier after reinforcement were created corresponding to steel plates of different  
Figure 2: Hysteretic curves of a bridge pier with pitting corrosion. (a) Pristine, (b) 5% corrosion. thicknesses. Figure 3 shows the hysteretic curves of the corroded bridge pier with a 5% pitting corrosion ratio reinforced by 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm steel plates. Figure 3 shows that with an increase in the steel plate thickness, the carrying capacity of the bridge pier increases significantly. For other corrosion ratios (10-20%), hysteretic curves can also be obtained. For simplification, in this work, only the hysteretic curves corresponding to 5% corrosion for reinforcement by steel plates with thicknesses ranging from 1 to 5 mm are presented. From Figure 3, it can be observed that, with an increase in the number of steel plates, the bridge has a significantly greater capacity to absorb energy. Based on Figures 2 and 3, the skeleton curves for different reinforcement cases corresponding to different corrosion ratios were obtained, as shown in Figure 4 (pitting corrosion) and Figure 5 (uniform corrosion). For pitting corrosion, Figure 4 clearly shows that regarding corrosion level, the load-carrying capacity of the reinforced bridge pier increases with the thickness of the steel plates. However, the thickness of the steel plates  
Figure 3: Hysteretic curves of a bridge pier with 5% corrosion strengthened by different thicknesses of steel plates. (**a**) 1 mm, (**b**) 2 mm, (**c**) 3 mm, (**d**) 4 mm, (**e**) 5 mm. that is necessary for the capacity of the reinforced bridge pier to be restored or exceed its original level is determined by the corrosion severity. Generally, a thicker steel plate is required for increased corrosion levels. The same conclusion can be drawn for a bridge pier with uniform corrosion. However, the results imply that pitting corrosion causes more severe damage than uniform corrosion does. Therefore, for the same corrosion level, thicker steel plates are required in the reinforcement for pitting corrosion piers. Based on the skeleton curves, the peak forces were extracted and are listed in Tables 2-5. For example, Table 2 lists the peak force for a bridge pier with 5% corrosion, reinforced by steel plates of different thicknesses. The peak force is 1321.8 kN for no corrosion, and that of the bridge with 5% corrosion is 1257.7 kN; the peak force reduces by approximately 4.85%. Tables 2-5 list the peak force ratios for the bridge pier before and after the reinforcement. A negative value in the table indicates that the peak force is smaller than its original state, while a positive value implies that the capacity of the reinforced bridge pier is greater. From Tables 2-5, it can be concluded that uniform corrosion has a smaller effect on the capacity of the bridge pier compared to that of the bridge pier with pitting corrosion.