Abstract: A decking plate is arranged on a cover plate over the open top of a U shaped channel, such that a through hole of the decking plate is positioned aligned over a cutout portion of the cover plate. A fixture is inserted through the through hole and the cutout portion. The fixture includes a head, a screw, a tube like portion and a protrusion. The cover plate and the decking plate are pinched and fixed together between the head and the protrusion of the feature. Thus, a positioned displacement of a attached plurality of plates can be prevented.

Abstract: Deckings include an upward hook and a receptacle. The upward hook is inserted into the receptacle. The receptacle has an opening immediately below a sidewall upper end portion that is continuous with the upper surface of the decking. The space between the deckings is restrained by engaging a tip of the upward hook behind the sidewall upper end. A fixture is mounted on the connection of the deckings. A base plate of the fixture extends from the portion of the deckings below the upward hook to the portion of the deckings below the receptacle. The base plate is fixed to the decking by a male screw, whereby downward movement of the upward hook is restricted.