Supporting device for steel box girder falling

A steel box girder falling construction device relates to the technical field of steel box girder construction and comprises a plurality of rectangular first heightening blocks (1) and a plurality of concave second heightening blocks (2), each first heightening block (1) comprises a peripheral channel steel frame and an internally poured reinforced concrete plate, and the side edges of the two first heightening blocks (1) are detachably and fixedly mounted to form a first cushion layer; each second heightening block (2) comprises a peripheral channel steel frame and an internally-poured reinforced concrete plate, the side edges of the two second heightening blocks (2) are detachably and fixedly installed to form a second cushion layer, and a rectangular cavity is formed in the second cushion layer; the first cushion layers are vertically piled, the second cushion layers are vertically piled, steel cushion plates (4) are arranged between the adjacent upper and lower heightening blocks, two supporting plates (5