Maintenance mode of middle beam for maintenance of large expansion joint

The invention discloses a middle beam maintenance mode for maintenance of a large expansion joint, and relates to the technical field of expansion joints. The method comprises the steps that S1, all center sills are restored to original positions through an expander (the distance between the center sills and side beams and the distance between the center sills are evenly distributed according to the existing telescopic space on site), and a damping limiting stopper is additionally arranged between every two pieces of profile steel and used for preventing the displacement amount of the center sills from exceeding the limit; s2, an original expansion joint water-stop belt is dismantled, sundries in a clamping groove of the expansion joint water-stop belt are cleaned through cleaning equipment, garbage in a center joint is cleaned, and a connecting chain petal of a damaged expansion joint is dismantled; and S3, the deviation rectifying expanders are installed in the beam gap between the squeezed edge beam and th