Bridge expansion device for bridge construction

The bridge expansion device comprises a first splicing block, a second splicing block, a fixed box and a movable block, the outer side of a vertical rod is sleeved with a first rotating arm in a sliding mode, a second rotating arm is coaxially arranged in the first rotating arm in a rotating mode, the upper end of the first splicing block is fixedly provided with a blocking strip matched with a protruding block in a sliding mode, and the upper end of the second splicing block is fixedly provided with a second rotating arm matched with the protruding block in a sliding mode. The vertical rod is provided with an elastic piece matched with the first rotary arm for supporting, and the vertical rod is provided with a meshing piece for limiting rotation of the first rotary arm. According to the bridge expansion device, rotation of the first rotating arm and the second rotating arm is controlled, the distance between the two splicing blocks is adjusted, and after the width range of the two splicing plates is matched