The precast beam is a kind of concrete beam member that is cast in the precast factory according to the design requirements of the engineering drawing, and is to be transported to the installation location of the engineering site after the strength reaches the design requirements. It mainly includes prefabricated concrete lintels. Precast concrete bridges are mostly prestressed members. The main feature is that it can be mass produced in advance, the installation speed is fast, and the construction period can be shortened.