To provide: a mount method of an inner diaphragm of a four-side weld box column capable of being constructed by a general weld method with a relatively small heat input amount of carbon dioxide arc weld, etc. and restricting an out-of plane deformation of a skin plate of the four-side weld box column by a relatively simple structure to reassure sufficient bearing force at a column beam connection part; the skin plate of four-side weld box column; four-side weld box column; and a concrete filling steel pipe column.SOLUTION: In the mount method of an inner diaphragm of a beam connection part of a four-side weld box column of a building, the inner diaphragm is configured with a plurality of diaphragm parts 3 divided and formed per adjacent part to each skin plate body 2 constituting the four-side weld box column, and before welding the skin plate body 2 in assembling in a box shape to form four-side weld box column, the diaphragm part 3 is welded into the skin plate body 2.SELECTED DRAWING: Figure 1
展开▼
