Abstract: A solventless method for the preparation and storage of uncured low vulnerability ammunition propellant (LOVA) includes blending from about 60 to 80 weight percent of either HMX or RDX oxidizer having a weight mean diameter from 1.0 to 14 microns with a polyurethane binder. A cure effecting amount of cure catalyst may also be included. These ingredients are blended at a temperature below about 110.degree. F., deaired, and optionally stored at low temperatures at a pre-cured condition, extruded and subsequently cured. The products produced thereby have uniquely low burning rates as well as uniquely low burning rate exponents.

Abstract: Proposed is a method for the erection of structures, such as bridges, that display pre-fabricated concrete beams, according to which the individual pre-fabricated beams are produced, on the spot, on a feed rigging within the corresponding work area of the structure, in a heated and laterally tiltable form. After removal from the form, the thusly produced pre-fabricated beams are transferred sidewardly into their final position by means of gantry cranes. During concretizing of the individual pre-fabricated beams, flexure of the feed rigging carrying the form is equalized in continuous fashion, in correspondence with the progressing, concretizing process, by transfer pumping of ballast liquid.

Abstract: An adjustable restraint assembly connectable between a dome portion of a solid propellant rocket motor casing and a rigid base or support, for use during the curing of a propellant in the casing. The assembly includes an upper attach bracket connectable to the dome portion, a lower attach bracket connectable to a rigid base, upper and lower flanges connected to the upper and lower brackets, respectively, and an adjustable threaded turnbuckle-like member connected between the flanges. The assembly is used to establish a maximum net downward deflection of the dome portion upon maximum pressurization of the uncured propellant in the motor casing and is thereafter adjusted at various times during the curing process to reduce and ultimately eliminate the deflection in increments to thereby improve the bond between the grains of the cured propellant and the casing in the region of the forward dome.

Abstract: A propellant charge and method of manufacture thereof by which the increase in maximum gas pressure within the upper use temperature range which occurs upon firing can be influenced until eliminated. The propellant charge is manufactured by compacting a first portion of the propellant charge which corresponds to between 50-80% of the total mass of the propellant charge, and then adding the balance of the propellant charge as loose powder on top of the first portion.

Abstract: A method and apparatus for laying a railroad track includes laying, in tandem, a series of pre-cast concrete slabs on a prepared track bed, the slabs being isolated from the bed, and from each other, by rubber isolation pads, and the slabs having cavities formed on the top faces. The rails are held above the slabs, in their proper location, by removable gauge beams having adjustment means to exactly locate the rails. Before filling the cavities with concrete the shoulder-pins, used to secure the rails, are located with their pin portions in the cavities by being removably secured to templates. The templates are held suspended above the slabs by being removably attached to a rail. The rails are used as guides after setting their exact gauge (separation), elevation and cant (angle of inclination) on the gauge beams, to determine the positions of the templates and shoulder-pins.

Abstract: Method for the casting of hollow slabs out of concrete by slide-casting. Concrete mix is extruded onto a base (18) preferably by means of a conical screw spiral (2). Thereinafter the mix is compacted by moving a cavity mandrel (3) fitted after the screw sprial. The end of the cavity mandrel (3) is moved along a path of movement of desired shape. The final end of the mandrel may be attached to the machine by means of a ball joint.

Abstract: Processes for the production of free-flowing, non-fibrous, alcohol-moistened nitrocellulose, characterized in that the water- or alcohol-moist nitrocellulose is softened with a solvent mixture of a nitrocellulose solvent and a lower aliphatic alcohol and water until the nitrocellulose fibers disappear, the alcohol-containing, liquid phase is decanted off from the two-phase mixture formed and the nitrocellulose-containing phase is processed into granulate using a screw extruder, the quantity of solvent mixture is used amounting to between 75 and 155% by weight, based on dry nitrocellulose, and the components of the mixture, NC-solvent:lower alcohol:water, being present in a ratio of 1:(0.2-4):(0.2-4).

Abstract: An apparatus 10 that extrudes, conveys and cuts a propellant strand into precise lengths independent of strand velocity is disclosed. Cutting of the strand is accomplished by a cutter 18 having a blade mounted on a shaft which in one revolution cuts the strand. The shaft is activated after passage of the strand end past a pair of downstream optic sensors; compensation is made for cutter delay and strand velocity by having cutting activation take place in the same amount of time as it takes the strand end to pass both sensors less cutter delay.

Abstract: The invention is concerned with a method for continuous slide-casting of large-size concrete objects or corresponding elements for compacting high-viscosity casting mix. The slide-casting mould (33) comprises a bottom plane (34), side walls (38, 39) of the mould, as well as means (37) for pressurizing the casting mix mechanically. According to the invention, before the parallel side walls (44, 54) at the outlet end of the slide-casting mould (33), within the casting line concerned, walls or wall portions (40 to 43, 50 to 53) are provided as fitted to each other or to their corresponding portions, provided as pairs, as pivotable always in the same direction around substantially vertical shafts (45 to 49, 55 to 59) included in their planes. The moving parts of the side walls (38, 39) may be displaced in pairs in the lateral direction, relative the casting direction, e.g., by means of cylinder-piston devices (61 to 63).

Abstract: Method for the continuous slide-casting of concrete objects for compacting the high-consistency concrete mix. Repeated parallel displacements back and forth are produced in the various regional zones in the high-consistency concrete mix placed in the mould by pivoting at least two opposite walls (10) of the slide-casting mould structure in the same direction relative parallel shafts (12) substantially parallel to each other and as synchronized relative each other, back and forth. Additional walls (4) fitted into the mould and forming oblong cavities, recesses or ribs in the concrete objects are pivoted in pairs with each other in the same direction and as synchronized with each other around shafts (7) placed at the ends of the additional walls next to the outlet end of the mould, the said shafts being substantially parallel to each other.

Abstract: A prefabricated monolithic reinforced concrete floor system is disclosed and claimed. Open web trusses are provided along a longitudinal dimension of a floor frame with rectangular tubular beams secured therebetween. Reinforcing elements are secured along upper surfaces of the open web trusses and the tubular beams where a floor is utilized and a reinforcing mesh material is draped thereover. Reinforcing clips may be received about the peripheral reinforcing elements to further reinforce edges of the floor. The concrete slab is produced in situ about the frame and totally encapsulates the reinforcing elements present while a lower surface of the slab is coterminous with an upper surface of the open web trusses and the tubular beams.

Abstract: A climbing form for progressively raising a form assembly in the construction of a concrete wall comprises has a support frame that adjustably carries a mast form unit, a main mast assembled with the frame for relative up and down movement, and a jib mast, equipped with a lifting means, extended upwardly from the main mast. A carriage within the main mast is releasably locked to the frame when the main mast is moved relative to the frame, and is releasable for up and down movement within the upper section of the main mast to raise and lower a jib form unit. A reversible nut and shaft drive means has the shaft rotatably supported in the mast upper section with the nut mounted on the carriage. With the lower section of the mast secured to the wall, and the frame and carriage in locked engagement, the drive means operates to raise the frame and carriage relative to the main mast to a new pouring position for the mast form unit.

Abstract: A method of lifting and stabilizing a concrete slab having an opening therein in which a plate is attached to the top surface of the slab, the plate having an opening coinciding with the opening in the slab, a hydraulic jack having a downwardly extending piston is removeably secured to the plate and a series of tubular shafts are forced downwardly through the opening in the plate and the slab to penetrate the earth beneath the slab and apply lifting force. When the slab has been lifted to the desired elevation, grout, such as a concrete slurry, can be injected below the slab so that the slab is stabilized in the selected elevational position. After the plate is removed the hole in the slab is filled.

Abstract: In a multiple-span bridge structure with side-by-side bridges, a scaffolding girder-formwork assembly is movable in the longitudinal direction of each bridge for constructing individual sections of the superstructure over support piers. After use on one bridge, the scaffolding girder-formwork assembly is movable to the other bridge by first rotating it about a vertical axis from the longitudinal direction of the bridge to the transverse direction while the assembly is centered over a pier of the one bridge. A support for the assembly is moved over a pier on the other bridge. Then the assembly is moved in the transverse direction until it is centered over the pier of the other bridge. Subsequently, the assembly is rotated into the longitudinal direction of the other bridge in position for constructing sections of the superstructure.

Abstract: Disclosed is a method and apparatus for extracting large form panels used in forming floor slabs on poured-in-place, multi-story concrete structures from beneath the slab they last formed. The preferred embodiment apparatus, called a panel picker, includes a frame held by a crane above and adjacent to the last formed slab; the frame is anchored to the slab and contains hoists on movable trolleys for attaching to and lifting the form panel. The movement of the trolleys permits attachment to the panel picker to be made in two steps and without the panel being unsupportedly cantilevered out to where a crane could attach directly to the panel.

Abstract: The invention provides a construction process permitting slab sliding and support means as well as simultaneous wall-erection, at the time such slab is being raised.

Abstract: The invention relates to a method for providing mechanical continuity and the transmission of stresses between two adjacent panels of a reinforced concrete wall cast in the ground, which is characterized by the use of a plurality of jacks the bodies of which are embedded in the concrete of a panel n and the stems are embedded in the concrete of the panel n+1. The invention is useful in the field of civil engineering constructional work.

Abstract: Floating dock for making elongate, cast concrete constructions by producing in sequence sections of the construction in a drainable work chamber. The dock has a base and a pair of permanent upstanding sides facing inwardly towards each other provided with a first set of fixed fastening members for locating anchoring members for the fastening of boarding members with associated reinforcing elements in a first position in the dock where a first section of the construction is cast. A second set of fixed fastening members in series with the first set is for fastening by way of corresponding anchoring members at least portions of the first section in a second position in the dock where a second section of the construction is moulded as a continuation of the first section.

Abstract: A tank is constructed and formwork apparatus is attached to that formed tank. The formwork apparatus is used to construct a tank supporting wall and jacking mechanisms included in that formwork apparatus lift the tank as the support wall is being formed so that the tank is carried upwardly by and on the supporting wall as that wall is constructed. The formwork is preferably slipforms.

Abstract: A method and apparatus is disclosed for continuously pumping flowable concrete mix to elevated heights for introduction into forms used in the fabrication of annular structures such as concrete hyperbolic cooling towers. A tower crane is erected in the center of the circle for the hyperbolic structure and concrete conveying piping is provided for raising mix to a lateral conduit carried by a secondary boom suspended from the swingable overhead jib of the crane. A pumping unit at ground level forces concrete mix up the vertical piping on the tower and then through the boom supported conduit for delivery into the form structure. The jib and thereby the boom suspended therefrom are swingable through an arc of 180.degree. in one direction to cover one half of the form structure and then the jib and boom may be swung in the opposite direction through the remaining 180.degree. arc for introduction of mix into the form structure.

Abstract: A concrete building is constructed by initially forming a generally circular concrete pad. A spherical or slighly more than hemispherical plastic mold is then erected on the concrete pad with a central post extending axially out the central top of the mold. Barbed wire is then wrapped around the mold and wire mesh is subsequently wrapped around the mold on top of the barbed wire, with the barbed wire serving to space the reinforcing wire mesh away from the surface of the mold. Concrete is then applied to the outside of the mold starting at the bottom of the mold adjacent the concrete pad and moving helically up the surface of the mold while laying concrete around the mold in strips. The apparatus for applying the concrete includes a frame mounted on wheels and pivoted on the post extending out of the top of the mold and being curved to follow the exterior surface of the mold.

Abstract: A method and apparatus for forming a structure having an inner surface in the form of at least one segment of a sphere. An inner support is mounted at a fixed point from which a radius can be struck to define the inner surface of the structure. An elongated radial member is pivotally connected at one end to the inner support with its other end being movable vertically and horizontally. A forming member at the other end of the elongated member has an outer surface in the shape of the inner surface of the segment to be formed. An actuator moves the elongated member horizontally and vertically to selected positions to place the outer surface of the forming member opposite and adjacent the inner surface of each segment being formed. A forming material is applied to the outer surface of the forming member while it is opposite and adjacent the inner surface of the segment being formed to form each segment directly on the forming member.

Abstract: A method of constructing a poured concrete structure protected from corrosive agents includes applying large-surface sealing elements to one surface of the structure before pouring the concrete. The sealing elements are attached to anchoring elements extending into a region into which concrete is to be poured. When the concrete is poured inside the sealing elements, the sealing elements are anchored in place by the anchoring elements which become set in the concrete. The sealing elements may have a high modulus of elasticity and be relatively rigidly affixed to the structure of may have a low modulus of elasticity and thus require overlapping perimeter areas for sealing of adjacent sealing elements.

Abstract: A self-propelled slip form, closed at its top, front, and sides, but open at its rear and bottom, provides a pressure chamber having the cross-sectional shape of a wall or similar structure to be cast. Such slip form may be advanced continuously at a slow rate or in stages, but whichever it is, the advance is due solely to pressure exerted against the closed front of the slip form through the intermediacy of the deposited, unset concrete or the like. Such pressure can be utilized to pre-stress reinforcing material on a continuous basis as it is fed into the pressure chamber simultaneously with deposit of the concrete or the like.

Abstract: In a slipform arrangement comprising a plurality of oblong, substantially rectangular mold plates arranged sequentially in a manner such that their end portions overlap each other there is provided an elongate post-like mold plate support means adjacent a short edge of an associated mold plate such as to support said plate in spaced relationship therewith, thereby to leave a gap for accommodating an end portion of a sequential mold plate, and tensioning means for creating in the region of said short edge a tensioning force directed substantially in the long direction of the post-like mold support. That part of the mold plate located nearest said short edge can be slightly angled towards the mold plate support means.

Abstract: An apparatus for forming embankments comprising a trapezium-shaped shield open at top and bottom and rearwardly. Material for the embankment is introduced into the top of the shield in slurry form and the difference in level between the slurry contained by the shield and the water outside the shield results in a force on the end wall of the shield. This causes the shield to travel end-wall first along the surface on which it is supported. As it moves forward, the shield will leave behind it an embankment formed to the same trapezium-shape as the shield itself. So that a layered form of embankment may be constructed, the shield may be fitted with a number of hoppers each associated with the formation of a particular layer.

Abstract: A method for casting multiple floor beams including the steps of assembling a multiplicity of spaced pan form units where the space between adjacent pan units forms the side of a beam form. A bottom panel is positioned between adjacent pan units to form the bottom of the beam form. The pan units are then locked together on their underneath sides to form an integral pan deck. Reinforcing framework is added into the beam forms and the pan form units are then locked together on their top sides. Concrete is then cast into the beam forms to form beams of a first floor level after which the underneath sides of the pan form units are unlocked and the bottom panel removed. The integral pan unit is then raised by jack means to a second floor level. During the time that the integral pan deck is being raised or after it is raised, the bottom panel is repositioned and the panels are again locked together on their underneath sides. The assembly is then in position in which the steps may be repeated.

Abstract: This invention pertains to a method and machine for slip forming concrete wall structures such as median barrier walls for highways. The slip form comprises a pair of opposite side walls each of which has a skirt member retractable and extensible relative to the lower portion thereof. A top wall separate from the side walls is mounted on the machine frame between the upper portions of the side walls, and each side wall and associated skirt member is movable as a unit relative to the top wall and each skirt member is independently movable relative to an associated side wall. The side walls are adjustably supported on the machine frame for adjustment laterally of the machine frame to accommodate top walls of varying widths and the top wall is verticaly adjustable relative to the machine frame independently of the side walls.

Abstract: Roofs of underground excavations are supported by forming sheet-material elements into tubes whose diameter can be varied by changing the overlap between the longitudinal edges of the rolled-up sheet material, standing the tubes upright to bear against the roof and the floor of the excavation, and filling them with hardenable material in flowable condition which, after hardening, will form a roof-supporting column.

Abstract: The invention provides a climbing framework for erecting concrete forms in the manufacture of straight or curved reinforced concrete walls, with anchoring members for removably anchoring the climbing framework to the wall, and with anchoring elements which as the wall is built, section by section, can be detached from one section and moved up for manufacture of the next-higher section.

Abstract: A reinforced elongated concrete slab is progressively formed on longitudinal supports following the installation of the supports by mounting carriages for movement along the length of the supports, providing the carriages with a leading platform portion to facilitate construction of a metal rod reinforcement core spanning the supports and a trailing slab forming platform.

Abstract: An elongated concrete structure, such as a bridge, is constructed by providing at a construction zone located at one end of the site of the structure a formwork arrangement which includes a bottom formwork within which the structure may be formed in discrete sections. Successive discrete sections formed in the formwork are joined together and launched in series from the construction zone toward the opposite end of the site across which the structure is to extend. As each section of the structure is launched, the bottom formwork is moved together with each section across one section length in the launching direction while the remainder of the formwork arrangement is maintained stationary at the construction zone.

Abstract: A slipform apparatus is described for forming a continuous upright monolithic lining within a preformed upright shaft. The slipform is provided in three independently movable sections that may be lowered into the shaft. Wet concrete is delivered to the sections and dispensed outwardly of the sections to form the lining. The formed sections hold the wet concrete against the walls of the shaft and progressively form a cylindrical upright bore within the shaft. As concrete is delivered to the slipform, the individual sections are moved in an "inchworm" effect in conjunction with an expansion mechanism to automatically lift itself upwardly within the shaft as the lining is being formed. A steering mechanism is provided to enable selective angular movement of the slipform in a nonvertical plane.

Abstract: A method for constructing concrete enclosures by means of casting two or three or more concrete plates one on top of the other, raising them o permanent or temporary structural posts and using the lifting motion of the plates to pour concrete in bottomless sideforms thus forming the walls.

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 beam clamp for securing a concrete form in forming beams, lintels, etc. having a pair of spaced apart legs secured together by a cross bar that permits one leg to pivot toward and away from the other leg and a pivoted lever operating as a cam for pivoting the first leg when mounting and dismantling the beam clamp from a form after the concrete has been poured and set.

Abstract: A method of slip forming concrete comprising moving concrete continuously through a formwork, and continuously extracting a portion of the water of said concrete prior to its release from said form.

Abstract: A fixed, linear, ground-based primary reflector having an extended curved sawtooth-contoured surface covered with a metalized polymeric reflecting material, reflects solar energy to a movably supported collector that is kept at the concentrated line focus of the reflector primary. The primary reflector may be constructed by a process utilizing well-known freeway paving machinery.

Abstract: A structure for supporting floor-molding forms in a multi-story building, including a truss that supports the forms and four telescoping leg units with upper ends pivotally connected to the truss, for supporting the entire weight of the truss on the previously-cast floor. The leg units are pivoted and telescoped out until the lower end of each leg unit lies on an area of the floor which is adjacent to a column or load-bearing wall of the building, within the 45.degree. shear plane lying about the column or wall, so that the weight of the truss and load thereon is transferred directly to the columns or walls to thereby eliminate heavy loading of the already-formed floor.

Abstract: Method and apparatus is disclosed for composting material such as refuse and preferably a mixture of refuse and sewage sludge. The material is piled in such a way that transverse tunnels are provided whereby natural air circulation is obtained into and through the material remains undisturbed during maturation, thereby allowing aerobic bacterial fermentation to progress efficiently and without interruption. Because higher stacks and consequent greater volumetric capacity thereof is attained, greater efficiency of space utilization. The apparatus involves core structures which temporarily support the material and form the tunnels or ventilation passages therein, the core structures being removed when the material becomes self-supporting.

Abstract: A method for guiding slip-forms in the casting of concrete structures where use is made of a rigid slip-form which is repeatedly lifted first at that side of the concrete structure being cast from which the slip-form is to be guided away, such that the slip-form when being lifted is shifted towards the opposite side where, in subsequent operations, it is repeatedly lifted to the same level as it was previously caused to occupy at the side from which the slip-form is to be guided away.

Abstract: The invention relates to a method for casting of concrete structures by means of moulds disposed at two opposite sides of the structure to be cast. The moulds are pressed against the concrete structure by the legs of a yoke construction which is arranged to be successively lifted by jacks cooperating with jack rods. The legs of the yoke construction are caused during lifting to slide directly or indirectly against the jack rods which are positioned between the legs of the yoke construction and the moulds.

Abstract: A new and improved method for forming a drainage structure, such as a manhole for a subterranean sewer pipe. In a first embodiment, a removable outer form is positioned in an excavation in the earth extending to the sewer pipe so that the earth surrounding the sewer may be undercut and removed through the removable outer form. Concrete is poured into the undercut area surrounding the sewer pipe to a height adjacent the lower edge of the outer form and a second cylindrical inner form is positioned within the outer form so that concrete may be poured into the space between the forms to form upwardly extending wall portions to the surface. In a second embodiment, the outer form is positioned in an excavation at a predetermined location and a concrete base portion is formed. The inner form is positioned in the outer form and predetermined quantities of sand are poured into the space between the forms for facilitating connection with sewer pipes.

Abstract: A slip form apparatus for the in place formation of a continuous concrete pipe in an open trench. The concrete material is supplied under high pressure to obtain a good and uniformly compacted pipe. The apparatus is automatically moved forward along the trench only when a properly compacted continuous pipe is being formed within the apparatus. Provided in the construction of the apparatus is the ability to temporarily stop the movement and formation of the pipe and then subsequently continue with the formation of the pipe without having to remove the apparatus from the trench. Also utilized in conjunction with the apparatus is a unique deployment arrangement for an inflatable film means located at a stationary position behind the apparatus to automatically supply support for the wet cementitious material as the pipe is being formed along the trench.

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: A method and apparatus for permanently joining at the jobsite of precast reinforced or prestressed posts and beams. The posts and beams are precast and will be used in the erection of the building when they have reached their maximum strength. Only sufficient concrete will be poured at the jobsite, as needed, to interconnect the posts and beams and perhaps the floors. Forms are used for joining together the adjacent ends of the posts and beams and providing therebetween a cavity into which concrete can be poured. The forms are preferably sectional so as to be separated and removed after the amount of concrete poured at the jobsite has set fully. These forms have clips thereon which can be connected with suitable guy supports for stabilizing the joint during the setting of the poured concrete therein.

Abstract: A method of building underground pipelines by forming a casing in a hole from a forming material which is compacted in the direction from the center of the hole toward its walls. The hole is first filled with the forming material throughout its cross-sectional area and then the material is compacted in the direction towards the walls of the hole. Compaction is effected by a device comprising a rod-shaped body adapted for moving through the hole, the front end of the body being provided with a system of radial ribs.

Abstract: An apparatus for the sequential production of concrete sections of a superstructure spanning a plurality of piers comprises a main girder positioned above a respective one of the piers and advanceable from pier to pier. A concrete form is carried by the girder for producing portions of each superstructure section, the concrete forms being movable along the girder. The main girder is supported on previously completed portions of the superstructure and can be advanced thereon by means of an auxiliary support in the center of the girder, two main supports positionable rearwardly of the auxiliary support and a third main support positionable forwardly of the auxiliary support. The main supports are in thrust and stress force bearing connection with the main girder and the main supports are movable along the girder in the longitudinal direction. The main supports may be retracted and lowered for vertically moving the main girder together with the concrete form carried thereby and any concrete therein.

Abstract: Climbing formwork for use in the erection of reinforced concrete structures in which the raising of the formwork from storey to storey is carried out by the use of movable vertically extending members the height of which when fully extended is in excess of the height of two storeys of a building to be erected, the members being maintained in their correct vertical positions by supporting tubes set into the concrete of the structure. The members carry between them beams or the like for supporting the outer forms and preferably some or all of the inner forms used for pouring the structure and are raised to a height equivalent to that of one storey of the structure after the completion of the pouring of the concrete of a storey. The vertically extending members are preferably in the form of double acting hydraulic cylinders having a piston extendable under hydraulic pressure, the extension of the piston being utilized for raising the forms.

Abstract: Continuous concrete pipe is produced in an open trench by drawing a sled along the trench. The sled has a fresh concrete intake chute which supplies the concrete to a pipe-forming mechanism that generates the pipe. The lower pipe half is supported by the trench. To support the upper pipe half, a plastic material is given a convex shape complementary to the concave interior of the pipe. The plastic material is formed over a convex mandrel carried by the sled forward (in the direction of movement of the sled) of the intake means so that the plastic material hardens before contacted by wet concrete from the intake means. The mandrel extends rearwardly past the intake means to provide support for the plastic mold while the pipe is formed. Alternative ways for making the plastic mold are described.