Abstract: A system for mass producing prestressed concrete railroad ties using a slip-forming method of casting concrete over a plurality of molds arranged side by side and end to end on a casting bed; a specially equipped continuous casting machine for slip-forming the railroad ties in an upside-down orientation; techniques an equipment for separating and removing finished railroad ties from the casting bed; a plant layout to facilitate casting and handling operations; a specially adapted apparatus for rotating groups of railroad ties to permit sticking thereof in rightside-up orientation.

Abstract: This invention relates to a method for making concrete conduit. The method of this invention pertains to forming a conduit mat of material on a form, advancing the formed conduit mat of material from the form, fastening the conduit mat together, cutting the conduit into desired lengths, applying concrete on the conduit mat, working the concrete from both the inside and outside of the conduit mat to form smooth surfaces on both surfaces of the concreted conduit mat and curing the concreted conduit mat to form concrete conduit. In one embodiment of this invention, the method is performed from a mobile base which moves forward as the concrete conduit is continuously made and layed on the ground or underwater.

Abstract: The invention relates to a method of forming a pre-stressed concrete member in which at least a bonding surface of a pre-cast concrete shell has the hydration process therein temporarily arrested by means of heat applied thereto such that reactivation of the hydration process after the stressing of the shell and prior to the pouring into the shell of infilling concrete, results in a strong bond being formed between the bonding surface of the pre-cast concrete element and the infilling concrete. The construction joints between the infilling concrete and the pre-cast concrete shell are thus of an improved integrity.

Abstract: Reinforced facings, including reinforcing webs entrained in hydraulic cement via a slurry bath, adhere to a nailable lightweight aggregate cementitious core to form a panel web. The reinforced web is formed on abutting conveyed carrier sheets, and the web is transversely cut, between the sheets, while moving or when stopped, in response to sensing of the sheets. The cut panels, on respective sheets are stacked for curing without damaging the panel edges and in a manner to minimize panel flex. Slurry bath, facing applicators, and cutter and stacking apparatus are included.

Abstract: In a method of manufacturing consecutive pre-tensioned concrete elements, e.g. concrete sleepers, in a long mould bed, reinforcement ropes are tensioned and closure members are placed between different elements. Prior to casting closure members which are so formed that two or more cast elements are joined together via bridges or shoulders projecting outwardly fron the elements and surrounding the reinforcement ropes are placed in the mould bed at predetermined intervals. The string of cast elements is advanced to an element-separating station at one end of the bed where the elements are successively cut by means of a diamond saw or the like. The bridges between the elements are formed in a manner such that the reinforcement ropes are protected and a small, preferably the smallest possible section of concrete between the elements is severed when the elements are separated from the string of elements.

Abstract: In the construction of a prestressed concrete structure, such as a bridge girder, forms for at least a part of the structure are built and a thin-walled sheathing tube is placed within the forms. Axially displaceable stiffener tubes extend through the sheathing tube. After the concrete is poured into the forms around the sheathing tube and sets, a steel bar is pushed through the sheathing tube and displaces the stiffener tubes. The steel bar can be left in the sheathing tube as the tendon or replaced with a tendon. Subsequently, the tendon is tensioned. Spacers encircling the steel bar keep it centered as it is pushed through the sheathing tube. Preferably, the stiffener tubes consist of an inner tube and an outer tube and each is made up of a plurality of short axially extending lengths with the joints of the inner tube staggered relative to the joints of the outer tube.

Abstract: A method and apparatus of prestressing reinforcing tendons in concrete products manufactured in separable moulds in a production line wherein the tendons are prestressed in a first product mould, a product is moulded in the first mould, a subsequent mould is then placed in series with the first mould, the reinforcing tendons are then prestressed between a point at the head of the production line and a previously moulded product.

Abstract: Method and apparatus for producing a concrete panel having a fractured rib finish is disclosed. A quantity of relatively low slump concrete mixture is cast upon a pallet in the form of a panel and is extruded to define projecting ribs and channels. The casting is permitted to harden until the concrete becomes rigid but not completely set. Thereafter an array of wedges secured to a carriage assembly is drawn along the length of the panel with each wedge disposed in shearing engagement with edge portions of an adjacent pair of ribs. Each wedge includes a shoulder portion wider than the channel for shearing and forcibly displacing portions of the ribs as the wedge is drawn through the channel. Means are provided for propelling the carriage assembly along the length of the panel and in a direction parallel to the orientation of the ribs. A concrete panel having a fractured rib finish produced by the method of the invention is similar in appearance to a concrete panel having a manually hammered rib finish.

Abstract: Shaped concrete compositions can be pre-stressed to obtain improved flexural strength by embedding nylon-4 reinforcing bars in a wet-laid concrete prior to curing.

Abstract: A steel concrete container with a roof formed as a suspended shell comprising sector-shaped precast, prestressed concrete elements and a reinforced concrete topping.

Abstract: A method of making a pre-cast concrete building panel wherein a sheet of hardboard is soaked in water, and while it is still wet, it is covered with a thin skin of concrete and there is formed a peripheral edge region of concrete to embed the hardboard edges. The subsequent drying out of the concrete and hardboard has the effect of binding together the hard-board and concrete, and pre-stressing the concrete.

Abstract: The portable tensioning system takes the place of permanently installed facilities including massive earth anchors for casting pre-stressed building units such as concrete beams. Such permanently installed casting beds must be demolished if they are to be subsequently removed. The portable system comprises a plurality of pre-cast modular segments with walls defining channels to serve as part of a casting bed. These segments are provided with longitudinal bores so that they can be transported to a building site, aligned in end to end relationship, and post-tensioned by passing strands through the aligned bores to provide an overall elongated casting bed. After the casting operation has been completed, the segments can be disassembled and transported to another site for re-use.

Abstract: A method is described for constructing a concrete building from precast concrete wall and floor panels. Each floor construction has a plurality of spaced-apart dowels which project upwardly above its surface along the proposed joint between the floor and a proposed wall, and each of the wall panels includes along its length vertical voids which extend for its full height at a spacing from one another generally the same as the spacing between the dowels projecting upward from the floor construction. The load bearing walls of the building are formed by erecting wall panels for the same vertically at the proposed joint with the dowels extending into the wall panel voids. Reinforcing rods are introduced into the voids to overlap the ones projecting upward from the floor, and the voids are filled with mortar to tie each of such wall panels to the floor below.

Abstract: A plastic foam core concrete plank and the method of making same is described which employs foamed plastic core forming members positioned on an initial layer of concrete in a forming pallet and held translationally and vertically in position relative to the initial layer of concrete as a top layer of concrete is poured into position around and over the core members to complete the slab. The core members have a plurality of discontinuous recesses extending from one surface thereof which are exposed to the lower or initial layer to create voids in the slab for light construction and to decrease the thermal transmissions therethrough.

Abstract: A method of making a metal reinforcing strip suitable for use in reinforcing a coating applied onto a pipe comprising providing a strip of welded wire mesh having longitudinal and transverse wires, and passing the strip between a pair of rollers which deform the longitudinal wires to an extent which increases progressively across the strip.

Abstract: Fibre reinforced composites of cementitious materials or gypsum are reinforced with pre-combined mixtures of strong reinforcing fibres e.g., glass or steel, and water absorbent fibres, e.g., cotton. Examples of composites are cement pipes, wall boards, etc.

Abstract: A method of forming a carriageway slab comprising two or more sections with expansion joints between the sections and stressed longitudinal tensioning members extending all the way through the sections is provided. In such structures, the space between sections where the expansion joints are provided is too small to insert a press to provide necessary stress to the longitudinal tensioning members. According to the invention, the tensioning members are formed in two parts, one part of each (a longer part) extending rearwardly from the front end plate of a section and the other or shorter part extending from the rear end plate. The front portion of the section is concreted and when the concrete is hardened, the tensioning members are stressed at the end of the concreted part and fixed in stressed condition, then the shorter parts of the tensioning members are attached to the corresponding longer parts and tension is applied to the shorter sections while the position of the adjacent ends at the joint is fixed.

Abstract: An elongated elevated box girder and roadway structure is constructed in a number of individual elongated sections with the support structure and formwork being reused, in turn, for each section. Each section is constructed in a number of stages. Initially, a support structure is built up from grade or is mounted on permanent upright members of the structure being formed, such as piers or abutments. Formwork for the bottom slab and the upright outside webs of the box girders are placed upon the support structure. Concrete is poured into the formwork for the bottom slab and webs and, after being allowed to set for a given period, and posttensioned, if necessary, the formwork is stripped and the support structure is removed. The support structure and formwork are then moved and set up for the next section to be constructed. The roadway slab includes the top slab of the box girder and cantilever sections extending laterally outwardly from each side of the top slab.

Abstract: The specification discloses a reinforcing fabric for concrete or the like and a method for making the same in which stirrup members are joined to the fabric by rigid joining members such that the stirrup members are retained generally in the plane of the fabric. The joining members are bendable, however, such that the stirrup members can be rotated to an erect position projecting away from the plane of the fabric. In an alternative embodiment, individual stirrup projections are joined to the fabric and are made of rigid but bendable materials so that they can individually be bent out of the general plane of the fabric.

Abstract: A method of manufacturing prestressed concrete pipe which comprises arranging a reinforcing cage in a form, casting expansive concrete within the form in such a manner that the reinforcing cage is disposed outwardly of the center of the wall thickness of the concrete layer, and then forming the pipe centrifugally.

Abstract: A structural element of concrete is selectively reinforced over that part of the surface where, when the element is loaded, tensile stresses can occur which might exceed the tensile strength of the concrete. The reinforcement comprises a relatively thin, integral external layer preformed from a cement composition reinforced with fibres disposed in a random two-dimensional distribution essentially parallel to the surface of the layer, the latter extending over the whole area of said part of the surface liable to tensile stress.

Abstract: A continuous piece of concrete is first cast in an elongated casting mould mounted on a prestressing bench; after transfer of the prestressing force to the hardened concrete, the continuous piece of concrete is cut into a series of sections, each containing a certain number of railway ties. These sections are then removed from the casting mould, placed on a roller conveyor and then brought to a second cutting station where they are cut to form individual units. The invention also concerns a novel construction of a casting mould for the specific manufacture of such tie.

Abstract: A process for producing reinforced concrete building units such as concrete floor panels having coffer-like inner holes with smooth upper and lower surfaces, comprises providing a layer of reinforced concrete on the lower edges of a building unit comprised by an upper panel and joining ribs intersecting each other. A reinforcing steel mat is secured to the lower edges of the ribs which is then immersed in a layer of concrete resting on a plate. The assembly is vibrated to consolidate the concrete around the mat and after hardening, the plate is removed, leaving a smooth undersurface on the resulting hollow construction. The panel can be prestressed to a downwardly convex shape, in which case the plate is given a corresponding upwardly concave curvature.

Abstract: Radially constrained arcuately arranged modules such as bricks are placed under compression by a device placed in a space between two of the modules, and a hardenable material is cast in the space to embed the compression device.The compression device has an elongated member provided with pivoted module-engaging feet at its opposite ends. The elongated member is extensible to move the feet apart and apply compressive retention forces to the modules.

Abstract: A method of manufacturing a support framework or truss having at least one suspension element arched in one direction and serving as a roof construction, formed from concrete poured at the site or from prefabricated components, comprising forming a reinforcement construction taking-up the horizontal forces and composed of two horizontal supports arranged in spaced relationship from one another and extending transversely with respect to the arching direction of the suspension element, and which horizontal supports are laterally interconnected by means of reinforcement components, and supporting the thus formed reinforcement construction upon supports. Tension elements for the suspension element are arranged in a spatial curve extending in a catenary configuration between the horizontal supports and are anchored at the region of the supports at the reinforcement construction.

Abstract: A method of installing a tendon in a duct in a slip-formed concrete structure including the steps of providing a tubular member which forms the uppermost part of the duct and whose upper end terminates at the level where the upper end of the tendon is to be anchored, said tubular member having outwardly extending abutment means at or adjacent its lower end, said abutment means being of such size and at such depth below the upper end of the tubular member as to enable the forces necessary to instal and support a tendon in the duct, at the time when the concrete structure reaches a height in the vicinity of the upper end of said tubular member, to be transmitted through the tubular member and distributed to the concrete structure by the abutment means at a level where the concrete has gained adequate strength for this purpose.

Abstract: A tendon anchorage for use in prestressing concrete members is disclosed which preferably includes a tubular mounting means mounted to extend over the tendon and through an opening in a bearing or anchor plate in order to secure the bearing plate in fixed and aligned relation to a tendon for casting the bearing plate into the concrete member in a predetermined orientation therein. Spacing means between the form board and the anchor plate allow the anchor plate to be cast into a recess in the concrete member. A wedge receiving housing and wedge assembly is positioned in alignment and in abutting relation with the bearing plate after casting of the bearing plate into the concrete.

Abstract: A method of moulding concrete ties or other similar articles having pre-stressed reinforcing wires or rods therein, wherein a series of open ended multi-cavity moulds of similar cross-sectional shape are aligned end to end in groups, wires are positioned in the aligned cavities of the moulds and are tensioned, the wires are separated from one another and into horizontal rows in each group by flat sided bar like spacers which are interposed between the ends of adjacent moulds of that group, while the groups themselves are separated by vertically movable spacer plates each having vertically extended slots which arrange the wires into vertical rows.

Abstract: A method of making stressed concrete articles made from a cement containing as an additive to portland cement a mixture of alumina cement, calcium sulfate and ground caustic lime, the method including hydrothermal treatment at 50.degree. C or above followed by curing in cold water for several days.

Abstract: The production of a moulded stressed concrete pipe in which stressed coated tendons are completely embedded in the finished article. The pipe is moulded in at least one longitudinal segment joined only by helically concentrically positioned tendons. The cured segments are then expanded radially to stretch and stress the tendons, the gap formed between the segments being filled with filler material to maintain the stress in the tendons. There is also disclosed a method where the tendons are stressed on a former prior to immersion of the tendons and former in a concrete pour. The former is segmented and collapsible so that the tension in the tendons can be transferred from the former to the concrete when it has cured, thus forming a stressed pipe structure.

Abstract: A plurality of cables to be prestressed and made a part of the final concrete slab, each have their ends secured within a plate with the overall arrangement of wires or cables being of a geometry substantially that of the desired final structural unit. A pair of lever bars pivotally related at their ends are connected to the plates such that when pivoted into straight line relation, the plate securing the ends of the cables are separated from one another, placing the wires in tension. The entire set of stressed cables and lever bars is lifted as a unit and placed onto a horizontal surface having upstanding means received through openings in the plates. Adjustment screws secure the plates to the upstanding means on the horizontal surface, after which the lever bars are removed. Concrete is poured over the tension cables, forming the structural slab, after which on setting up, the end plates are removed from the wires, leaving the prestressed concrete slab with implanted tension wires.

Abstract: A method of moulding concrete ties in a series of open ended multi-cavity moulds which are arranged to have corresponding cavities aligned, and comprises positioning reinforcing wires in the aligned cavities and straining the wires, positioning spacers between adjacent ends of adjacent moulds and between the wires, filling the moulds with wet concrete to surround the wires, removing the spacers after the concrete has set and releasing the tension on the wires, severing the wires between adjacent moulds, coupling a tilt frame to one side of a mould frame and a base frame, the tilt frame comprising a pivot having a longitudinal axis, and lifting the other side of the mould frame to thereby pivot the mould frame about the longitudinal axis, lowering the mould frame to invert it and discharging the ties from the inverted moulds.

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: 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 method of making a metal reinforcing strip suitable for use in reinforcing a coating applied onto a pipe comprising providing a strip of welded wire mesh having longitudinal and transverse wires, and passing the strip between a pair of rollers which deform the longitudinal wires to an extent which increases progressively across the strip.

Abstract: A method of producing a prestressed beam of steel or steel and concrete having at least one flange in which a plurality of spaced apart transmission elements arranged symmetrically with respect to the center of the span of the beam are secured to the flange, tensioning wires are attached to each two symmetrically disposed transmission elements with the wires extending at predetermined distances from the flange, tensioning the wires to apply to the beam, via the transmission elements, on the one hand solely compressive forces and, on the other hand, in positions corresponding to each transmission element, a bending moment which is opposite to that of the loads to be applied in use, and applying a stress to the beam during the tensioning of the wires substantially to counteract the bending moments. At least one guide element for the wires may be disposed between two symmetrically disposed transmission elements to prevent lateral buckling of the beam during tensioning of the wires.

Abstract: Process and device for shaping components made of mortar or concrete in which the temperature of the concrete is reduced to a value which makes it possible to freeze concretes and mortars.

Abstract: Thermal prestressing methods using unit and selective heating of tendons incorporated in a ceramic or cermet body to selectively elongate the tendon with respect to the body and soften the latter. Upon cooling an anchorage bond is formed between the body and the ends of the tendons, which bond develops a tension in the tendon and prestress in the body upon further cooling. Bodies are also prestressed by forming a bond between the tendon and the body and then heating the body in use so as to elongate the tendon relative to the body, the tendon having a greater coefficient of expansion than the material of the body.

Abstract: A method of assembling building structures utilizing precast concrete building units which are positioned side-by-side and end-to-end as well as stacked to form a multistory structure; the units being secured together by tendons freely threaded through horizontal and vertical chases provided in the building units, placed under tension and anchored at their extremities.

Abstract: A method for anchoring a ring tensioning member in a circular container, especially a concrete tank or a concrete tube is characterized by cutting out at least one recess in the wall thickness of said container for locating therein a hemispherical anchorage body in overhung position having on its circumference at least one slot and through bores for a bracing cable. The bracing cable which has been inserted in the wall of said container and prestressed by a stretching mechanism will be anchored in said anchorage body, whereafter the recess will be covered in such a way as to be in alignment with the surface of said container.

Abstract: A structural component, such as a load-bearing column or a floor panel, is initially made undersize between two opposed faces and is brought to accurate size and the angularity of said faces made accurate, by locating the component relative to a reference surface, with a gap between that surface and one of the faces, that face is provided in the gap with a layer of settable material capable of adhering to the face, and this material is squeezed by relative adjustment between the reference surface and an abutment to give the component the desired accuracy.