During the construction and operation of the bridge, there will be cracks, transverse, longitudinal and oblique cracks in different parts of the beam. Once the crack appears, it will affect the structural durability, will directly affect the bearing capacity of the structure, and even endanger the safety of the structure. It is worthy of attention and should ascertain the cause of cracks,we must take appropriate measures to repair.

1. The structure has little or no great influence on the structure itself, mainly by the way of surface sealing and repairing: mortar sealant, crack glue injection reinforcement, chisel inlay and surface shotcreting.

2. The structure has no effect, long-term erosion caused by rain and gas on the structure have a greater impact on the use of pressure grouting to repair, is a slurry (such as cement and epoxy resin grout) by applying certain pressure into the structure to achieve the internal crack, crack closure, restore and enhance the structure strength and durability and impermeability.

3. The larger cracks have damaged the structure. The following methods are dealt with: steel plate bonding reinforcement, carbon fiber fabric bonding and reinforcement, increasing beam section size reinforcement, prestressed carbon plate reinforcement and so on.