Abstract: Apparatus for the rapid production of concrete having a grout slurry forming device, a cyclonic mixer for aggregate and a weighing device for feeding weighed amounts of aggregate to the cyclonic mixer. The slurry forming device including, subjecting fine particles in a liquid to the action of one or more rotating disc shaped blades, arranged to create within the slurry alternating areas of high and low pressures, thereby breaking up agglomerations. The cyclonic mixer includes, a hopper in which at least two conveyors simultaneously transport aggregate streams tangentially into, in opposite directions inducing helical mixing paths. The weighing device including, an aggregate weigher wherein a number of aggregate storage bins selectively releases aggregate onto a variable speed controlled conveyor. Intimately mixed concrete being formed from the simultaneous release of the grout slurry into the cyclonic mixer combining with the mixing aggregate.

Abstract: As a means of casting concrete floors in concrete and other structures the invention provides a type of formwork in which a platform is supported from vertical elements of the structure, the platform having vertically extending housing means depending from its under side which are associated hinged formwork members. The arrangement is such that the formwork may be set up so that one or more concrete floors of a building may be cast, the hinged formwork members being arranged in a horizontal position so as to form a support for the floor or floors. After casting and setting of the concrete the hinged formwork members are folded into the housing so that the platform may be raised vertically drawing the housing and formwork members through apertures left in the cast floors. The floors are completed by filling the apertures with concrete.

Abstract: A roof structure made up by a plurality of truss members interconnected by purlins which carry sheet metal roofing material. The truss members are made up of a top compression member which is preferably a tube and a bottom tension tube the members being connected together by vertical tension struts and joined at their ends. The top compression member of each truss consists, before erection of a straight or partially curved member and the bottom tension tube of a downwardly bowed tube. The structure is given form and rigidity by passing high tension steel cables through the bottom tension tubes and, after the purlins and sheet metal roofing material have been attached, tensioning them to bring the top compression members to an upwardly curved configuration and the bottom tension tube to a straight or slightly upwardly bowed form.

Abstract: A roof structure consisting of a thin curved slab of reinforced concrete which is initially cast by conventional techniques as a flat slab, tension cables (preferably of high tensile steel) extending in one or more directions being arranged across the slab and being connected to opposite edges of the slab and also connected to the slab at points along their lengths by means of tensioned hangers or compression props or columns of predetermined lengths, tension then being applied to the cables to cause them to straighten and in so doing to cause the concrete slab to take up a curved shape so as to form a shell structure which resists applied loads by reason of its curved shape.

Abstract: A concrete structure in which a post-tensioned concrete slab is supported by columns, each column being surrounded or partly surrounded by an area of concrete in the form of a hollow inverted pyramid, the column passing through the apex of the pyramid. The area concerned is formed integrally with the remainder of the slab and is of substantially uniform thickness sloping downwardly from the surrounding concrete towards the column at an angle .theta. to the horizontal such that tan .theta. lies in the range of 0.1 to 0.25 or in the case of a column near an edge or corner of the structure 0.1 to 0.35.

Abstract: A building comprising a plurality of structurally stable building cells is disclosed, wherein the cells are structured so that each forms at least part of a room of the building. Each cell has at least three planar, substantially vertical walls having an average thickness of about 1/4 inch to about 2 inches, except in areas of localized thickening. The cell has a roof in the form of a structure having substantially the structural action of a double curved thinshelled dome, which extends from the tops of the walls to form an integral concrete structure. The roof has a rise to chord ratio between 1:10 and 1:60. The roof is also about 1/4 inch to about 2 inches thick, except in areas of localized thickening. The roof and the top of the walls are joined by a continuous edge stiffening member, and a floor is joined to the bottom of the walls. Two or more of these cells are stacked one over the other in a generally vertical relationship in the building.