Construction method for demolition system of inclined-legged rigid frame overpass bridge for highway reconstruction and extension

The invention relates to a construction method of a demolition system of a slant-legged rigid frame overpass bridge for reconstruction and extension of a road. The construction method comprises the following steps: demolition operation is performed on a concrete guardrail; setting up a shaped assembly bracket at the midspan and the 1/4 span on one side; cutting and separating the upper end and the lower end of the inclined leg, and transporting away from the construction site through the inclined leg temporary fixing protection bracket; and the main beam segments are hoisted away in a segmented mode through the segment hoisting auxiliary bracket. The movable protection platform has the beneficial effects that the movable protection platform is arranged below the main beam of the inclined-leg rigid frame bridge, so that the safety under the bridge during the cutting period of a concrete guardrail and the main beam is effectively ensured, and the influence of construction activities on the existing traffic is r