Single-column pier bridge reinforcing structure with adjustable additional support and construction method of single-column pier bridge reinforcing structure

The invention provides an additional support with an adjustable transverse position, a single-column pier bridge is reinforced based on the additional support, the bridge comprises a beam body, a single-column pier and a bearing platform, and a reinforcing structure comprises a perforated bottom plate, a horizontal perforated sliding connection plate, an L-shaped additional support, a steel inclined strut, a sliding groove structure, a baffle, a single rod and an anchor bolt; a perforated bottom plate is arranged on the periphery of the single-column pier, a sliding groove is formed in the perforated bottom plate, a horizontal perforated sliding connection plate is installed in the sliding groove, an L-shaped additional support is arranged on the horizontal perforated sliding connection plate, the L-shaped additional support is provided with a sliding groove structure, and a single rod is installed in each sliding groove structure in a hinged mode through a sliding block. And the other ends of the four single