## 1 Introduction
The effects of using bonded steel reinforcements on cracked concrete beams were concluded to be primarily related to the size of the steel plates. [PERSON] et al. [30] analyzed the connection between the steel plates and the concrete in a steel plate reinforcement. It was concluded that the bearing capacity of the concrete beam strengthened using bonded steel plates was not only related to the section area of the steel plate but also its anchorage mode. [PERSON] et al. [31; 32] analyzed a mechanism for improving the flexural resistance and shear resistance of RC beams using riveted steel plates. A recommended formula for calculating the flexural and shear capacities of the RC beams strengthened using anchored steel plates was subsequently proposed along with construction measures for riveted steel plate reinforcement. [PERSON] [33] used a fatigue test to analyze the changes in the mechanical properties of the concrete beams strengthened using bonded steel plates under a fatigue load. The results showed that the fatigue failure law of bonded steel reinforced beams conformed to the three-stage law of internal damage in concrete. The deflection gradually increased with the increase of the number of fatigue load cycles. The deflection after two cycles was approximately 1.46 times the initial deflection. With regards to comparison studies conducted on the reinforcement of concrete members using steel plates and carbon fiber cloths, [PERSON] and [PERSON] [34; 35] studied the mechanical strengths and fatigue properties of concrete beams with reinforced carbon fiber and steel plates and compared them to unreinforced specimens in terms of the related mechanical properties. It was found that the deflections and crack widths of the reinforced components were relatively small, and their ultimate bearing capacities were significantly greater. Moreover, it was found that the fatigue performance of the concrete specimens strengthened using carbon fiberboards and steel plates could be improved. [PERSON] [36] and others conductedfatigue tests and a fatigue load finite element simulation analysis on concrete beams strengthened using steel plates and CFRP, respectively. The mechanical properties of concrete strengthened using bonding reinforcement technologies were studied. The results showed that under a constant fatigue load, the stress of the CFRP cloth of concrete beams strengthened using CFRP increased with increasing fatigue cycles; however, the steel plates in the concrete beams strengthened using steel plates experienced bond failure after a certain number of fatigue load cycles. At present, research on the durability of bridge structure reinforcement is mostly conducted for healthy structures, while the mechanical performance of damaged and healthy reinforced structures is different and depends on the type and degree of damage. Moreover, research on the relationship between durability deterioration and structural fatigue characteristics is limited. The deterioration of the durability of reinforced bridge structures affects the fatigue lives of the reinforced structures and leads to a loss of the reinforcement effect. The prestressed hollow slab is a bridge structure widely used in highway and municipal engineering. However, owing to overloading, adverse environmental erosion, and low design standards for early bridges, the durability of a prestressed slab in service significantly deteriorates; therefore, it must be reinforced. However, the lack of research on the durability of prestressed concrete hollow slab reinforcement and its impact on the fatigue life of the structures has resulted in several bridges prematurely losing their reinforcement effect because of a significant deterioration of reinforcement durability and the rapid decay of fatigue life after being strengthened. This poses a hidden danger to the safety of projects.