Construction method of prestressed concrete gate-type pier crossing existing railway bridge

The invention discloses a construction method of a prestressed concrete gate-type pier crossing an existing railway bridge. Common construction methods of the prestressed concrete gate-type pier crossing the existing railway bridge comprise a support cast-in-place method, a prefabrication installation method and a steel box formwork method. The method comprises the steps that pier column concrete is poured; pouring concrete at the first part of the cover beam, wherein the first part of the cover beam is arranged above the pier column; hoisting the steel box template, and connecting the steel box template with the first part of the bent cap; concrete at the second part of the cover beam is poured, and the prestressed steel beam is tensioned; and the bolts are removed, the steel box formwork is removed, and construction of the gate-type pier cover beam is completed. According to the construction method, the bent cap is divided into two parts for construction in sequence, the second part of the midspan bent cap