Large-span steel truss incremental launching steel nose girder

The invention discloses a large-span steel truss incremental launching steel nose girder. The large-span steel truss incremental launching steel nose girder comprises a nose girder main body, wherein the nose girder main body comprises two truss plate units; each truss plate unit comprises an upper chord member, a lower chord member and a plurality of diagonal rods; the diagonal rods of each truss plate unit are arranged between the corresponding upper chord member and the corresponding lower chord member and are 'W'-shaped; the nose girder main body comprises a first nose girder section at the front end and a second nose girder section at the rear end; the first nose girder section and the second nose girder section are connected together through a third nose girder section with the variable cross section; each of the first nose girder section and the second nose girder section consists of a plurality of segments; the distance between each two segments defines a panel length; the ratio of the nose girder height of the first nose girder section to the panel length is equal to the ratio of the nose girder height of the second nose girder section to the panel length; and the nose girder height of the first nose girder section is smaller than that of the second nose girder section. By the nose girder with the length of 120 m, a pier of which the maximum net value of a cantilever is 160 m and the maximum span is 180 m can be designed.