Abstract: A floor-ceiling system for multi-story buildings which utilizes a bottom membrane having significant tensile strength supported on the building frame, such membrane being either cast in place and supported by shoring or prefabricated and self-supported, with void-producing duct forms regularly arranged and supported on the membrane, and a poured-in-place plastic material covering the membrane and duct forms to create structural elements alternating with the duct forms to form a substantially finished floor-ceiling system when the plastic material cures. The duct forms may be provided with access openings to the floor or ceiling or with lateral access openings interconnecting each other. The duct forms may be left-in-place forms or inflatable tubes removed when deflated after the material cures. Finishing materials for the floor or ceiling such as carpeting or acoustical tile may be secured directly to the essentially planar bottom or top surface of the system.

Abstract: An improved cellular floor, wall or the like structure is disclosed. The structure in a specific embodiment disclosed, includes a covered raceway for electrical conductors. The raceway has a plurality of knockouts in its cover, and is covered by and at least partially supports a poured concrete floor. The improvement is a plurality of cooperating piston-cylinder assemblies on the raceway cover. Each of the assemblies is a cylinder with a concrete piston therewithin. The cylinder is positioned so that its projection on the raceway cover is larger than and covers one of the knockouts. The piston is capable of limited axial movement within the cylinder, and has an end in substantial contact with one of the knockouts. The piston end is of such size and shape that, when driven toward the knockout, the piston will drive the knockout into the raceway and enter the knockout opening.