Method for erecting section steel cantilever structure support frame

The invention discloses a method for erecting a section steel cantilever structure support frame, which comprises the following steps of: step 1, arranging a plurality of I-shaped steel beams vertical to a wall at equal intervals on a structural slab of a second floor below a cantilever structure of a building along the horizontal direction; step 2, arranging two steel wire ropes at the top end of a cantilever part of each I-shaped steel beam, wherein a triangle surface formed by the two corresponding steel wire ropes and each I-shaped steel beam is a vertical face; step 3, erecting a vertical frame above each I-shaped steel beam; step 4, tensioning all the steel wire ropes to enable the cantilever parts of the I-shaped steel beams to be kept level; step 5, erecting a first pull rod, a big slanting pole, a second pull rod and two small slanting poles on each vertical frame, wherein the first pull rods, the big slanting poles, the second pull rods and the small slanting poles are all positioned on the vertical faces on which the vertical frames are positioned; step 6, tensioning all the steel wire ropes again. The method is suitable for concrete pouring construction of a cast-in-place concrete cantilever structure and particularly suitable for concrete pouring construction of a larger cantilever structure.