Shallow water through arch bridge construction device and construction method thereof

The invention provides a shallow water through arch bridge construction device and a construction method thereof.The shallow water through arch bridge construction device comprises two rows of side beam frames and two rows of bottom beam frames, the side beam frames are located on the outer sides of the bottom beam frames, a connecting beam system is arranged between the side beam frames and the bottom beam frames, two movable portal cranes are arranged on the side beam frames, and walking hanging beams are arranged on the portal cranes; a plurality of sliding lifting blocks are arranged on the lifting beam; the bottom beam frames on the two sides are used for installing middle cross beams and arch rib supports. The side beam frame, the bottom beam frame and the arch rib support are sequentially detached and hoisted from the middle to the two ends of a river through cooperation of the portal crane and the hoisting beam, a steel trestle is not needed in the arch bridge building process of the whole device, mea