Patent ID: 8713867

Claim:
A unit structural member supporting a floor plate by utilizing an M-shaped channel which is constituted with a center U-shaped channel section and right and left U-shaped channel sections continuously formed to share right and left side plates of the center U-shaped channel section as a channel trench of the center U-shaped channel section and respective channel trenches of the right and left U-shaped channel sections being opened in opposite directions, comprising: a pair of longitudinal beams formed of long pieces of material of the M-shaped channel as being arranged in parallel at an established distance; and a number of lateral beams formed of short pieces of material of the M-shaped channel as being arranged in parallel laterally between the parallely-arranged longitudinal beams at established distances in the longitudinal direction of the longitudinal beams, wherein bottom plates of the right and left U-shaped channel sections of the M-shaped channels which form the pair of longitudinal beams and bottom plates of the right and left U-shaped channel sections of the M-shaped channels which form the lateral beams are overlapped and the longitudinal beams and the lateral beams are connected at the overlapped faces, the unit structural member is arranged in a state that the M-shaped channels which form respective longitudinal beams are arranged in parallel one above the other, and the floor plate is supported by an upper longitudinal beam of the unit structural member.