Abstract: To prepare a split frustoconic jaw intended for the anchoring of a cable, a part is first taken bounded externally by a frustoconic surface and hollowed by a cylindrical axial channel whose inner surface is advantageously striated. This part is sawed into by substantially axial and radial slashes leaving bridges to subsist of small thickness at the bottom of these slashes throughout the central channel. An assembly ring is mounted in an outer annular groove and the whole is subjected to cementation treatment so as to surface harden the jaw while making the bridges fragile.

Abstract: To prepare a split frustoconic jaw intended for the anchoring of a cable, a part is first taken bounded externally by a frustoconic surface and hollowed by a cylindrical axial channel whose inner surface is advantageously striated. This part is sawed into by substantially axial and radial slashes leaving bridges to subsist of small thickness at the bottom of these slashes throughout the central channel. An assembly ring is mounted in an outer annular groove and the whole is subjected to cementation treatment so as to surface harden the jaw while making the bridges fragile.

Abstract: The invention relates to the prestressing of a concrete work by means of a relatively long stretched sinuous cable (1) formed by a bundle of several metal strands (2)housed individually in plastic material tubes (3). The different tubes with their strands are positioned without special precautions in a sheath (5) buried in the work then a sufficiently unctuous and fine cement grout (6) is injected into this sheath for filling the spaces in the sheath between the tubes and strands are tensioned individually after solidification of the injected cement grout, by means of relatively light automatically operated actuating cylinders.

Abstract: To manufacture a bent prestress conduit (5) adapted to receive without damage cables (7) subjected to extremely high pulling forces, one of the faces of a metal strip (1) is coated intimately with a metal phosphate layer (4) itself covered by a soap and this metal strip is wound in helical form so as to obtain a continuous tube whose inner face is formed by the thus coated face of the metal strip.

Abstract: For joining together two concrete slabs (1, 2) juxtaposed side by side along a crack (3), a cylindrical cartridge with vertical axis is used comprising two half shells (4.sub.1, 4.sub.2) made from cast metal and joined vertically together by a key (11) housed in recesses (10.sub.1, 10.sub.2) each formed in a central projecting step (9.sub.1, 9.sub.2), these half shells being urged mutually horizontally apart by a continuous elastic belt (12) made from an elastomer material adapted to ensure sealed isolation of the inside of the cartridge with respect to the outside.

Abstract: For greasing the end of a reinforcement (2) surrounded by a sheath (3) and retained in a truncated cone shaped ring of jaws (6) coacting with a truncated cone shaped housing (5) formed in an anchorage plate (4), which housing is closed by a cap (11), a longitudinal rectilinear groove (12) is formed in this housing and in this cap is formed an orifice (13) automatically aligned with the groove at the end of fitting of the cap and the inner volume of the assembly is filled with grease through a rectilinear hollow needle (14) passing successively through said orifice and said groove.

Abstract: The invention provides an anchoring device for a pre-stress cable formed from several filaments or strands (4), comprising a bearing plate (1), a block (2) pierced with truncated cone shaped holes (2.sub.1) through each of which passes a filament or strand of the cable, said block resting on said plate and truncated cone shaped jaws (3) for jamming the filaments or strands in their holes. The bearing plate (1) is pierced with multiple holes (1.sub.1) extending those (2.sub.1) of the block (2) so that this plate supports this block over the whole of its non pierced surface.

Abstract: The invention relates to a device for connecting aligned butt ends of isostatic elements (generally girders) of a constructive work. Between the crosspieces connecting the opposite girder butt ends there is disposed at least one tubular cylinder prestressed by clamping screws and by a coaxial tensioned tie rod whose ends bear on the outer faces of the crosspieces. The invention is more particularly applicable to bridges formed by independent isostatic girders.

Abstract: The invention has for its object a device for connection between two rectilinear portions of a stretched cable, said device passing through a massive constructive work.According to the invention said device transmits the tension from one of the portions of cable to the other by a segment of cable of which the strands, curved along the desired incurvation, are separated from one another and stretched, with a total tension force at least equal to that of the more stretched of the two portions of cable, to ensure precompression of the portion of massive structure which these strands traverse.

Abstract: The present invention relates to elongated elements of concrete pre-stressed by tensioned reinforcements adherent to this concrete. Each element comprises a box capping its end to which the reinforcements are fixed and which is provided with a flange allowing tensioning of the reinforcements and the possible assembly of two elements end to end. The invention is applicable to all structures formed by elements pre-stressed by adherent reinforcements, and in particular to driven-in piles.

Abstract: A swiveling device for tensioning a pre-stress bar having a threaded end projecting from an end face of the element to be pre-stressed comprises a jack having a movable part attached to the bar and a fixed part bearing against the element. A first bearing plate is mounted on the end face of the element around the bar and includes an annular spherical cup surface. A swivel joint nut is threaded on the end of the bar and has a spherical ball part seated in the cup surface of the first bearing plate forming a first swivel joint. A second bearing plate is slidably disposed on a face of the first bearing plate and includes a second annular spherical cup surface. The end of the fixed part of the jack proximate the element includes a spherical surface seated in the second annular spherical cup surface forming a second swivel joint.

Abstract: Apparatus for releasing the means for gripping a pre-stress cable, to allow the cable to be detensioned. Each strand is usually maintained in the tensioned state by a cone truncated group of gripping means enveloping this strand. According to the invention each of the gripping means of a group surrounding a strand comprises towards the outside an extension which, in the active state of the gripping means, is spaced apart from this strand, all the extensions thus determining a volume of revolution terminating towards the outside by a hooking flange, while the extractor is formed by resilient parts distributed along the generatrices of a cylinder and comprises inwardly turned hooking flanges, the circumference determined by all the inner edges of the projections in the state of rest being of smaller diameter than that of the volume formed by the outer surface of the extensions of the gripping means beyond their hooking flange, when these gripping means are in the active state.

Abstract: A device for removing from their moulds elements made of pre-stressed concrete employing stretched adherent reinforcements on a "long bed" and passing through at least one row of moulds of said elements, wherein, prior to the release of the tension of the reinforcements, each of the elements is detached from its mould by an upward thrust exerted on at least one movable portion of the bottom of this mould, then maintained in lifted position until the tension is released and these reinforcements are cut.