Overall assembling method for ultra-wide framing steel box girder

The invention discloses an overall assembling method for an ultra-wide framing steel box girder, and relates to the technical field of steel box girder assembling. The method comprises the steps performing plate unit manufacturing and plate assembly welding, beam section matching assembly welding and pre-assembling and pre-assembling inspection; carrying out beam section assembly welding accordingto the sequence of a bottom plate, a transverse partition plate, a middle top plate, a primary positioning inner web plate, an anchor web plate, other top plates, a secondary positioning anchor web plate, a middle cross beam and a cantilever arm block, and carrying out three-dimensional stepped propelling mode section-by-section assembly and welding; and during pre-assembling, with considerationof the influence of beam section compression amount caused by welding circular seam shrinkage amount and cable force on the length, correcting the accumulated total length and error of the previous pre-assembling in the next a