Viaduct steel structure construction method

The invention discloses a viaduct steel structure construction method. According to the method, a viaduct steel structure comprises a main beam plate, wherein a bearing steel frame is installed in themiddle of the bottom of the main beam plate, two sets of parallel supporting steel frames are installed at positions, close to the two sides of the bearing steel frame, of the bottom of the main beamplate correspondingly, each supporting steel frame comprises a corresponding bottom steel beam, inclined steel beams are installed at positions, close to the two ends of the bottom steel beams, of the tops of the bottom steel beams correspondingly, a top supporting plate is installed between the tops of the two sets of inclined steel beams, a plurality of sets of clamping bases are installed at the top of the top supporting plate, a plurality of sets of butt joint bases are arranged at the bottom of the main beam plate, a welded beam is arranged on a center line of the bottom of the main beamplate, a plurality of sets