Forming method for structure for reinforcement and structure for reinforcement

A method of forming a reinforcing structure, comprising:

• a first forming operation of forming a side flange to form a flange angle with a bottom surface of a steel plate by folding up an edge of the steel plate in a first direction;
• a second forming operation of forming a pair of side wall flanges by folding the steel plate in a second direction, and simultaneously, bending at least a portion of the side flange in a direction opposite to the first direction;
• and
• a third forming operation of folding up the side flange in the first direction,
• wherein in the first forming operation, the steel plate is folded up such that the side flange formed on one side of the steel plate is bent, and the side flange is bent by folding up an edge of the steel plate such that the bottom surface of the steel plate and the side flange form different angles,
• wherein in the second forming operation, the pair of side wall flanges facing each other is formed, by folding the bottom surface of the steel plate in the second direction to form a pair of corners,
• wherein in the second forming operation, an upper flange, a partial region of the bottom surface of the steel plate, is present between the pair of side wall flanges, and the steel plate is folded in such a manner that the pair of side wall flanges are spaced apart from each other by the upper flange,
• wherein in the second forming operation, at least portions of the upper flange and the side flange are formed to be located at the same height, by folding the side flange having the same height as the upper flange and a height higher than the upper flange in a direction other than the first direction,
• wherein the second forming operation is performed so that at least a portion of the side flange, which is a flat portion, is at the same height as the upper flange, and deformation is applied to the corner portion at which the side flange, the side wall flange, and the upper flange meet, so that stretching does not occur at the corner,
• wherein the third forming operation is performed by folding up at least a portion of the side flange, which is the flat portion, having the same height as the upper flange in the first direction, and
• the first forming operation, the second forming operation, and the third forming operation are performed sequentially.