Giant crane beam mounting method

The invention relates to a construction method, in particular to a method for installing super-large crane beams, solving the technical problems of the prior art in the installation of large-span and large-mass crane beams. The method for installing the super-large crane beams comprises the following steps: a temporary bracket is first put up on the ground at one third of the span of a crane beam installation position; a crane beam is assembled on site; a left-segment crane beam component and a middle-segment crane beam component which are welded together are integrally lifted in place by use of two cranes; the left-segment crane beam component is partially fixed with a steel column connecting part; the other end of the middle-segment crane beam component falls on the bracket; a right-segment crane beam component is lifted to the height in accordance with the middle-segment crane beam component by use of another crane; and the right-segment crane beam component and the middle-segment crane beam component are paired and welded in the air. The method is applicable to the installation of the crane beam of which the length is over 60 meters and the mass is over 220 tons. The method has the advantages of high safety performance, short construction period, convenient construction operation and good engineering quality.