Device for gradually reducing height of temporary support during suspension bridge construction period

The invention discloses a device for gradually reducing the height of a temporary support during the suspension bridge construction period. The device comprises a support top plate, a support bottom plate, a sand tank, fine sand and valves. The support top plate is connected with the lower side of a steel truss girder lower chord, a support rubber layer is arranged on the lower side of the support top plate, and the support bottom plate is arranged under the support rubber layer. The sand tank is formed by arranging four sand tank side plates on a sand tank bottom plate, an upper opening structure is formed, the fine sand is contained in the sand tank, the support bottom plate is arranged on the top face of the fine sand, seams are reserved between inner outlines of the sand tank side plates and the periphery of the support bottom plate, and the valves used for discharging the fine sand are arranged on the sand tank side plates. The sand tank bottom plate is placed on the top face of a bridge tower lower cross beam and connected with the top face through bolts, and the sum of the thickness of the fine sand and the thickness of the sand tank bottom plate is the height, needing to be increased, of the support. The sand tank hoops the fine sand so that the fine sand can support the support bottom plate, the fine sand is synchronously and symmetrically discharged through the valves, and stepless lowering of the support can be achieved.