EP0227546A2 - Devices for stressing tendons before anchoring - Google Patents
Devices for stressing tendons before anchoring Download PDFInfo
- Publication number
- EP0227546A2 EP0227546A2 EP86402826A EP86402826A EP0227546A2 EP 0227546 A2 EP0227546 A2 EP 0227546A2 EP 86402826 A EP86402826 A EP 86402826A EP 86402826 A EP86402826 A EP 86402826A EP 0227546 A2 EP0227546 A2 EP 0227546A2
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- EP
- European Patent Office
- Prior art keywords
- tie rod
- jaw
- ribbons
- traction
- jaws
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
- E04G21/00—Preparing, conveying, or working-up building materials or building elements in situ; Other devices or measures for constructional work
- E04G21/12—Mounting of reinforcing inserts; Prestressing
- E04G21/121—Construction of stressing jacks
Definitions
- the invention relates to the tensioning of tie rods, a first end of which has been previously anchored on a first anchoring span of a rigid structure.
- Such structures are for example made of concrete, in which case the tie rods ensure the prestressing of this concrete by post-tensioning.
- the structures in question could also be of any other type, and in particular suspension bridges, the tie rods of which would then constitute the shrouds.
- the invention relates more particularly, among the tensioning devices of the kind in question, those for which the grip of the end of tensioning rod is ensured by provisional tightening of a jaw whose jaws overlap this end, said tightening being generated using a cylinder supplied with a pressurized fluid.
- each jaw is applied to the tie rod by means of an externally threaded and split core radially surrounding this tie rod and cooperating with an internally threaded sleeve forming part of the fixed or mobile element of the jack.
- This core is mounted so as to move axially with the tie rod in short strokes to cause it to be tightened and loosened radially.
- the object of the invention is, above all, to remedy this drawback.
- the traction devices according to the invention are essentially characterized in that the provisional clamping pressure of each jaw is applied to the tie rod by jaws which can be moved exclusively in transverse directions relative to the jack element on which this jaw is mounted.
- Each jaw is a wedge having on the one hand a face oriented parallel to the axis of the tie rod, face capable of being applied transversely against this tie rod and on the other hand an opposite oblique face suitable for cooperating by sliding with a complementary part mounted so that it can move parallel to the axis of the tie rod
- the tie rod is constituted by a bundle of parallel flat ribbons and each clamping jaw comprises a rigid plate pierced with an opening traversed by said bundle of ribbons, a plurality of rigid plates each having a central portion interposed contiguously between two successive ribbons and two portions projecting transversely beyond these ribbons and resting on the plate, two prismatic jaws arranged on either side of the wafer-ribbon assembly and each having a flat face applied against a ribbon and an opposite oblique face, the oblique faces of the two corners being oriented so as to converge in the direction away from the structure, a
- the invention includes, apart from these main provisions, certain other provisions which are preferably used at the same time and which will be more explicitly discussed below.
- Figure 1 of these drawings shows in schematic longitudinal section a tensioning device established according to the invention in its rest state.
- Figures 2, 3 and 4 show the same device in schematic longitudinal half-section in respectively three stages of its operation.
- the tie rod 1 to be tensioned is constituted by a bundle of parallel flat ribbons 2 each formed for example by a steel strip or by an element made of composite material (material comprising a matrix of plastic material reinforced by continuous parallel fibers), as taught by the patent cited above.
- the tensioning device under consideration comprises a platform 6 hollowed out at its center by an opening 7 itself traversed by the tie rod 1, said platform being supported at a certain distance above the block 3 by a base 8.
- a traction cylinder V1 comprises a cylinder 9 with a vertical axis secured to the platform 6 and a piston 10, the rod 11 of which opens vertically above this cylinder 9.
- the latter is supplied with compressed fluid by intake and exhaust pipes or vice versa 12,13.
- the rod 11 is extended at its top by a rigid horizontal plate 14 itself pierced by a central opening 15 crossed by the tie rod 1.
- the platform 6 and the plate 14 each carry a jaw 20.30 suitable for gripping the tie rod 1 at the corresponding level.
- Each of these jaws 20.30 includes: a plurality of plates 21, 31 each comprising a central portion interposed contiguously between two strips 2 and two overhanging end portions resting on the corresponding plate 6 or 14, two prismatic corners 22, 32 each having a flat face applied contiguously against a strip 2 and an opposite oblique face, the oblique faces of the two corners converging upwards, - a frame 23,33 having two sides conforming to clean corners to slide against the oblique faces of the above corners so as to exert a horizontal clamping force on the latter and on the stacks of ribbons and plates which they frame when a trapping force is applied vertically downwards on this frame, - And a clamping cylinder V2, V3 capable of generating such a force and comprising a cylinder 24, 34 of vertical axis secured to the corresponding plate 6 or 14 and a piston 25, 35 whose rod 26, 36 is secured to the frame concerned 23.33.
- Each clamping cylinder V2, V3 is supplied with pressurized fluid by intake and exhaust pipes or vice versa 27,37; 28.38.
- the mutual contact surfaces of the wafers and tapes, their coefficient of mutual friction (preferably increased by roughening the surfaces of the wafers and possibly hardening them by heat treatment) and the force of the horizontal tightening of the tapes against the wafers must be sufficient to prevent any sliding of the ribbons relative to the plates when a longitudinal tension is exerted on these ribbons in the manner which will be specified below.
- this high jaw 30 is raised by activating the traction cylinder V1, which causes its rod 11 to rise upwards, and this until its maximum extension, as shown in FIG. 2, which gives the tensioner a first tension T1.
- this upper jaw 30 has again returned to its low position, it is tightened again so that it in turn takes over from the lower jaw 20 for maintaining the tension T1 in the tie 1: this lower jaw 20 can then be loosened and the cycle described above can be completely repeated.
- the control of these successive cycles is advantageously made automatic by making the tool comprise an appropriate pressurized fluid distributor and a device suitable for measuring the tension applied to the tie rod 1 by the traction cylinder during each active operating phase of this jack corresponding to the progressive exit of its rod 11.
- the tensioned tie rod 1 is anchored on block 3 in any desirable manner.
- a jaw 40 similar to those described above, that is to say comprising: intermediate plates 41 each having a central portion interposed contiguously between the ribbons 2 and two transversely overhanging end portions resting on the block 3, - two prismatic corners 42, a frame 43 capable of interacting with the corners 42, - And a cylinder V4 itself comprising a cylinder 44 integral with the encroachment 8 and a piston 45 extended downwards by a rod 46 adapted to bear against the frame 43, said cylinder V4 being served by intake pipes and discharge of pressurized fluid 47,48.
- the anchoring is then carried out by activating the cylinder V4 in the direction which irreversibly biases the frame 43 downwards.
- This anchoring could be achieved in any other desirable way, for example by tightening the tie rod 1 between two rigid bars urged towards each other using high strength bolt-nut systems, all of these bars and of these systems framing the stack of ribbons 2 and interlacing plates 41 to be tightened.
- the anchoring thus described takes over from the two clamping jaws 20 and 30 for maintaining the tension T in the tie rod 1 so that these two jaws can be loosened (FIG. 4), then release the set of tensioning tools, which can be used to tension another tie rod.
- This device has many advantages over those previously known and, in particular, the following: - the various tightenings exerted by the jaws on the tie rods implement exclusively transverse displacements of the jaws applied to these tie rods, which excludes any recoil and relaxation of said tie rods during these tightenings: the maximum value of traction obtained at the end of each stroke of the traction cylinder can thus be maintained, the gripping jaws can be easily loosened during successive cycles and the desired tension T can be applied with precision to the tie 1 because of the total independence which exists between this tension and the clamping forces of said gripping jaws, - by playing on the obliquity of the mutually coagulating flat faces of the corners and of the frames, it is possible to adjust at will the jamming forces to be developed by each of the cylinders V2, V3 and V4 to generate determined clamping forces and particular to obtain relatively low values for these forces.
- the invention is not limited in no way to those of its modes of application and embodiments which have been more especially envisaged; on the contrary, it embraces all variants thereof, in particular those in which the tie rod is not in the form of parallel ribbons, but in that of cylindrical cables or strands, the clamping jaws then comprising radially split jaws of revolution surrounding said cables or strands, said jaws being hollowed out by a cylindrical bore, externally bounded by a frustoconical surface, and adapted to interact with complementary frustoconical housings hollowed out in axially movable rings.
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- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Mechanical Engineering (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Piles And Underground Anchors (AREA)
- Clamps And Clips (AREA)
- Vehicle Body Suspensions (AREA)
- Jib Cranes (AREA)
- Reinforcement Elements For Buildings (AREA)
- Ropes Or Cables (AREA)
- Hand Tools For Fitting Together And Separating, Or Other Hand Tools (AREA)
- Warping, Beaming, Or Leasing (AREA)
- Knitting Machines (AREA)
- Rod-Shaped Construction Members (AREA)
Abstract
Description
L'invention concerne la mise sous tension des tirants dont une première extrémité a été préalablement ancrée sur une première portée d'ancrage d'un ouvrage rigide.The invention relates to the tensioning of tie rods, a first end of which has been previously anchored on a first anchoring span of a rigid structure.
Elle concerne plus précisément les dispositifs pour exercer une traction sur la seconde extrémité d'un tel tirant en vue de son ancrage sur une seconde portée d'ancrage de l'ouvrage rigide, après mise sous tension dudit tirant, de façon à solliciter en permanence les deux portées l'une vers l'autre.It relates more precisely to the devices for exerting traction on the second end of such a tie rod for its anchoring on a second anchoring seat of the rigid structure, after tensioning said tie rod, so as to permanently urge both carried towards each other.
De tels ouvrages sont par exemple constitués en béton, cas dans lequel les tirants assurent la précontrainte de ce béton par post-tension.Such structures are for example made of concrete, in which case the tie rods ensure the prestressing of this concrete by post-tensioning.
Les ouvrages en question pourraient également être de tout autre type, et notamment des ponts suspendus dont les tirants constitueraient alors les haubans.The structures in question could also be of any other type, and in particular suspension bridges, the tie rods of which would then constitute the shrouds.
L'invention concerne plus particulièrement, parmi les dispositifs de mise en tension du genre en question, ceux pour lesquels la prise de l'extrémité de tirant à tendre est assurée par serrage provisoire d'une mâchoire dont les mors chevauchent cette extrémité, ledit serrage étant engendré à l'aide d'un vérin alimenté par un fluide sous pression.The invention relates more particularly, among the tensioning devices of the kind in question, those for which the grip of the end of tensioning rod is ensured by provisional tightening of a jaw whose jaws overlap this end, said tightening being generated using a cylinder supplied with a pressurized fluid.
Avec ces dispositifs de mise en tension connus, on commence par serrer la mâchoire autour d'une portion, de l'extrémité de tirant à tendre, située du côté, de la portée d'ancrage correspondante, eloigné de l'ouvrage, puis on éloigne la mâchoire ainsi serrée de ladite portée d'ancrage jusqu'a obtention de la tension désirée dans le tirant, après quoi on ancre le tirant tendu sur la portée et on desserre et dégage la mâchoire.With these known tensioning devices, one begins by clamping the jaw around a portion, from the end of the tensioning rod, situated on the side, of the corresponding anchoring span, away from the structure, then move the jaw thus tightened away from said anchoring seat until the desired tension is obtained in the tie rod, after which the tensioned tie rod is anchored on the seat and the jaw is loosened and released.
Lorsque le tirant à tendre est relativement long, la course d'ancrage sus-indiquée entre la mâchoire et la portée d'ancrage est elle-même relativement grande et, comme les efforts de traction à engendrer sont alors eux-mêmes relativement élevés, on est obligé d'avoir recours à des outillages de traction particulièrement encombrants, lourds et difficiles à mettre en oeuvre, ce qui peut constituer un inconvénient majeur, en particulier lorsque la traction doit être exécutée sur place, en des lieux souvent difficilement accessibles.When the tension rod is relatively long, the above-mentioned anchor stroke between the jaw and the anchoring range is itself relatively large and, as the tensile forces to be generated are then themselves relatively high, it is necessary to have recourse to traction tools which are particularly bulky, heavy and difficult to implement. work, which can constitute a major drawback, in particular when traction must be carried out on site, in places that are often difficult to access.
Pour écarter cet inconvénient, il a déjà été proposé de faire comprendre aux dispositifs de traction du genre en question, en plus d'une première mâchoire de serrage provisoire de tirant elle-même montée sur l'élément axialement mobile d'un vérin longitudinal de traction dont l'élément fixe est propre à prendre appui sur la portée d'ancrage, une seconde mâchoire de serrage provisoire de tirant montée sur l'élément fixe du vérin de traction, ces mâchoires et ce vérin étant actionnables par des fluides sous pression et des moyens étant prévus pour commander automatiquement de façon répétitive le cycle des admissions et échappements de fluide permettant d'assurer la traction désirée du tirant par reprises successives.To overcome this drawback, it has already been proposed to make traction devices of the kind in question understand, in addition to a first provisional clamping jaw pulling itself mounted on the axially movable element of a longitudinal cylinder traction, the fixed element of which is capable of bearing on the anchoring surface, a second temporary tightening jaw of the tie rod mounted on the fixed element of the traction cylinder, these jaws and this cylinder being actuated by fluids under pressure and means being provided for automatically repetitively controlling the cycle of admissions and escapements of fluid making it possible to ensure the desired traction of the tie rod by successive recoveries.
Dans le mode de réalisation qui a été proposé pour un tel dispositif, la pression de serrage provisoire de chaque mâchoire est appliquée sur le tirant au moyen d'un noyau fileté extérieurement et fendu radialement entourant ce tirant et coopérant avec un manchon fileté intérieurement faisant partie de l'élément fixe ou mobile du vérin.In the embodiment which has been proposed for such a device, the provisional clamping pressure of each jaw is applied to the tie rod by means of an externally threaded and split core radially surrounding this tie rod and cooperating with an internally threaded sleeve forming part of the fixed or mobile element of the jack.
Ce noyau est monté de façon a se déplacer axialement avec le tirant selon de faibles courses pour provoquer ses serrages et desserrages radiaux.This core is mounted so as to move axially with the tie rod in short strokes to cause it to be tightened and loosened radially.
En d'autres termes, après chaque phase de traction exercée sur le tirant, il est nécessaire de faire reculer et donc de détendre ce tirant pour assurer le serrage subséquent de la mâchoire solidaire de l'élément fixe du vérin, ce qui réduit d'autant la traction exercée et ne peut être admis pour l'exercice d'efforts de traction élevés.In other words, after each phase of traction exerted on the tie rod, it is necessary to roll back and therefore to relax this tie rod to ensure the subsequent clamping of the jaw secured to the element. fixed cylinder, which reduces all the traction exerted and can not be admitted for the exercise of high tensile forces.
L'invention a pour but, surtout, de remédier à cet inconvénient.The object of the invention is, above all, to remedy this drawback.
A cet effet les dispositifs de traction selon l'invention sont essentiellement caractérisés en ce que la pression de serrage provisoire de chaque mâchoire est appliquée sur le tirant par des mors déplaçables exclusivement selon des directions transversales par rapport à l'élément de vérin sur lequel cette mâchoire est montée.To this end, the traction devices according to the invention are essentially characterized in that the provisional clamping pressure of each jaw is applied to the tie rod by jaws which can be moved exclusively in transverse directions relative to the jack element on which this jaw is mounted.
Dans des modes de réalisation préférés, on a recours en outre à l'une et/ou à l'autre des dispositions suivantes :
- chaque mors est un coin présentant d'une part une face orientée parallèlement à l'axe du tirant, face susceptible d'être appliquée transversalement contre ce tirant et d'autre part une face opposée oblique propre à coopérer par glissement avec une pièce complémentaire montée de façon à pouvoir se déplacer parallèlement à l'axe du tirant,
- le tirant est constitué par un faisceau de rubans plats parallèles et chaque mâchoire de serrage comprend une plaque rigide percée d'une ouverture traversée par ledit faisceau de rubans, une pluralité de plaquettes rigides présentant chacune une portion centrale interposée jointivement entre deux rubans successifs et deux portions débordant transversalement au-delà de ces rubans et reposant sur la plaque, deux mors prismatiques disposés de part et d'autre de l'ensemble plaquettes-rubans et présentant chacun une face plane appliquée contre un ruban et une face oblique opposée, les faces obliques des deux coins étant orientées de façon à converger dans le sens qui s'éloigne de l'ouvrage, un cadre entourant les coins et présentant deux côtés conformés de façon à glisser contre ces coins et à serrer l'ensemble coins-plaquettes-rubans quand il est sollicité vers l'ouvrage, et un vérin dont l'élément fixe est solidaire de la plaque et dont l'élément mobile, déplaçable parallèlement aux rubans, est solidaire du cadre.In preferred embodiments, use is also made of one and / or the other of the following arrangements:
- Each jaw is a wedge having on the one hand a face oriented parallel to the axis of the tie rod, face capable of being applied transversely against this tie rod and on the other hand an opposite oblique face suitable for cooperating by sliding with a complementary part mounted so that it can move parallel to the axis of the tie rod,
the tie rod is constituted by a bundle of parallel flat ribbons and each clamping jaw comprises a rigid plate pierced with an opening traversed by said bundle of ribbons, a plurality of rigid plates each having a central portion interposed contiguously between two successive ribbons and two portions projecting transversely beyond these ribbons and resting on the plate, two prismatic jaws arranged on either side of the wafer-ribbon assembly and each having a flat face applied against a ribbon and an opposite oblique face, the oblique faces of the two corners being oriented so as to converge in the direction away from the structure, a frame surrounding the corners and having two sides shaped so as to slide against these corners and to tighten the wedge-wafer-ribbons assembly when it is biased towards the structure, and a jack whose fixed element is integral with the plate and whose mobile element , movable parallel to the ribbons, is integral with the frame.
L'invention comprend, mises à part ces dispositions principales, certaines autres dispositions qui s'utilisent de préférence en même temps et dont il sera plus explicitement question ci-après.The invention includes, apart from these main provisions, certain other provisions which are preferably used at the same time and which will be more explicitly discussed below.
Dans ce qui suit, l'on va décrire un mode de réalisation préféré de l'invention en se référant aux dessins ci-annexés d'une manière bien entendu non limitative.In what follows, a preferred embodiment of the invention will be described with reference to the accompanying drawings in a manner which is of course not limiting.
La figure 1, de ces dessins montre en coupe longitudinale schématique un dispositif de mise sous tension établi selon l'invention en son état de repos.Figure 1 of these drawings shows in schematic longitudinal section a tensioning device established according to the invention in its rest state.
Les figures 2, 3 et 4 montrent le même dispositif en demi-coupe longitudinale schématique en respectivement trois étapes de son fonctionnement.Figures 2, 3 and 4 show the same device in schematic longitudinal half-section in respectively three stages of its operation.
Dans l'exemple illustré, le tirant 1 à mettre sous tension est constitué par un faisceau de rubans plats parallèles 2 formés chacun par exemple par un feuillard d'acier ou par un élément en matériau composite (matériau comprenant une matrice en matière plastique armée par des fibres continues parallèles), ainsi qu'il a été enseigné par le brevet cité ci-dessus.In the example illustrated, the
On se propose de mettre sous tension le tirant 1 considéré en vue de son ancrage sur un bloc rigide 3 percé d'une ouverture 4 et porté par un ouvrage 5 en béton déjà pris.It is proposed to tension the
Pour simplifier la description qui suit, on supposera que l'extrémité à ancrer du câble 1 débouche verticalement vers le haut au-dessus de l'ouvrage en béton.To simplify the description which follows, it will be assumed that the end to be anchored of the
Mais toute autre orientation serait bien entendu envisageable sans sortir du cadre de l'invention : on peut même observer qu'en pratique c'est l'orientation horizontale qui est la plus courante pour les extrémités de tirants à ancrer.But any other orientation would of course be possible without departing from the scope of the invention: can even observe that in practice it is the horizontal orientation which is most common for the ends of tie rods to be anchored.
Le dispositif de tension considéré comporte une plate-forme 6 évidée en son centre par une ouverture 7 elle-même traversée par le tirant 1, ladite plate-forme étant supportée à une certaine distance au-dessus du bloc 3 par un piétement 8.The tensioning device under consideration comprises a
Un vérin de traction V₁ comprend un cylindre 9 d'axe vertical solidaire de la plate-forme 6 et un piston 10 dont la tige 11 débouche verticalement au-dessus de ce cylindre 9.A traction cylinder V₁ comprises a
Ce dernier est desservi en fluide comprimé par des canalisations d'admission et d'échappement ou inversement 12,13.The latter is supplied with compressed fluid by intake and exhaust pipes or vice
La tige 11 est prolongée à son sommet par une platine rigide horizontale 14 elle-même percée par une ouverture centrale 15 traversée par le tirant 1.The
La plate-forme 6 et la platine 14 portent chacune une mâchoire 20,30 propre à saisir le tirant 1 au niveau correspondant.The
Chacune de ces mâchoires 20,30 comprend :
- une pluralité de plaquettes 21,31 comportant chacune une portion centrale intercalée jointivement entre deux rubans 2 et deux portions terminales débordantes reposant sur la plaque correspondante 6 ou 14,
- deux coins prismatiques 22,32 présentant chacun une face plane appliquée jointivement contre un ruban 2 et une face oblique opposée, les faces obliques des deux coins convergeant vers le haut,
- un cadre 23,33 présentant deux côtés conformes en coins propres à glisser contre les faces obliques des coins ci-dessus de façon à exercer un effort de serrage horizontal sur ces derniers et sur les empilages de rubans et plaquettes qu'ils encadrent lorsqu'une force de coincement est appliquée verticalement vers le bas sur ce cadre,
- et un vérin de serrage V₂, V₃ propre à engendrer une telle force et comprenant un cylindre 24,34 d'axe vertical solidaire de la plaque correspondante 6 ou 14 et un piston 25,35 dont la tige 26,36 est solidaire du cadre concerné 23,33.Each of these jaws 20.30 includes:
a plurality of
two
- a
- And a clamping cylinder V₂, V₃ capable of generating such a force and comprising a
Chaque vérin de serrage V₂, V₃ est desservi en fluide sous pression par des canalisations d'admission et d'échappement ou inversement 27,37 ; 28,38.Each clamping cylinder V₂, V₃ is supplied with pressurized fluid by intake and exhaust pipes or vice
Les surfaces de contact mutuel plaquettes-rubans, leur coefficient de frottement mutuel (de préférence augmenté en rendant rugueuses les surfaces des plaquettes et en les durcissant éventuellement par traitement thermique) et la force du serrage horizontal des rubans contre les plaquettes doivent être suffisants pour empêcher tout glissement des rubans par rapport aux plaquettes lorsqu'une tension longitudinale est exercée sur ces rubans de la manière qui va être précisée ci-après.The mutual contact surfaces of the wafers and tapes, their coefficient of mutual friction (preferably increased by roughening the surfaces of the wafers and possibly hardening them by heat treatment) and the force of the horizontal tightening of the tapes against the wafers must be sufficient to prevent any sliding of the ribbons relative to the plates when a longitudinal tension is exerted on these ribbons in the manner which will be specified below.
La construction de l'ensemble des vérins V₁, V₂ et V₃ est de révolution autour de l'axe vertical du faisceau de rubans 2 : seuls ces rubans, les plaquettes, les coins et les cadres affectent des formes autres qu'annulaires.The construction of all the cylinders V₁, V₂ and V₃ is of revolution around the vertical axis of the bundle of ribbons 2: only these ribbons, the plates, the corners and the frames have shapes other than annular.
Pour mettre sous tension le tirant 1, on procède comme suit.To tension the
Initialement tous les vérins se trouvent en leur position "rentrée", c'est-à-dire pour laquelle la tige du piston est rentrée au maximum, vers le bas pour le vérin V₁ et vers le haut pour les vérins V₂ et V₃ (figure 1).Initially all the cylinders are in their "retracted" position, that is to say for which the piston rod is retracted as far as possible, down for the cylinder V₁ and up for the cylinders V₂ and V₃ (figure 1).
On commence par serrer la mâchoire haute 30 autour du tirant 1 en activant le vérin de serrage V₃, ce qui abaisse le piston 35 et applique fermement le cadre 33 sur les coins 32.We start by tightening the
Puis on élève cette mâchoire haute 30 en activant le vérin de traction V₁, ce qui fait sortir sa tige 11 vers le haut, et ce jusqu'à son extension maximum, comme représenté sur la figure 2, ce qui confère au tirant une première tension T₁.Then this
On serre alors la mâchoire basse 20, de niveau constant, autour du tirant 1 en activant le vérin de serrage V₂, ce qui abaisse le piston 25 ainsi que sa tige 26 et que le cadre 23 porté par cette dernière.Then tightens the
A partir de l'instant où ladite mâchoire basse 20 est serrée, celle-ci peut prendre le relais de la mâchoire haute pour le maintien de la tension T₁ dans le tirant 1.From the moment when said
On peut alors sans risque de relâchement de cette tension :
- desserrer la mâchoire haute 30 en désactivant le vérin V₃, ce qui relève son piston 35,
- puis desactiver le vérin de traction V₁, ce qui abaisse le piston 10 ainsi que la mâchoire haute 30 qu'il supporte, en rentrant la tige 11 dans le cylindre 9 (figure 3).We can then safely release this tension:
- loosen the
- Then deactivate the traction cylinder V₁, which lowers the
Une fois cette mâchoire haute 30 parvenue à nouveau en sa position basse, on la serre à nouveau de façon qu'elle prenne à son tour le relais de la mâchoire basse 20 pour le maintien de la tension T₁ dans le tirant 1 : cette mâchoire basse 20 peut alors être desserrée et le cycle décrit ci-dessus peut être intégralement répété.Once this
Chaque nouvel actionnement du vérin de traction V₁ confère au tirant 1 un complément de traction.Each new actuation of the traction cylinder V₁ gives the
Le cycle ci-dessus est répété jusqu'à ce que le tirant 1 soit soumis à la valeur totale de traction désirée T, la course parcourue par le piston de traction 10 lors du dernier cycle pouvant être seulement une fraction de sa course totale.The above cycle is repeated until the
La commande de ces cycles successifs est avantageusement rendue automatique en faisant comprendre à l'outillage un distributeur de fluide sous pression approprié et un appareil propre à mesurer la tension appliquée sur le tirant 1 par le vérin de traction lors de chaque phase active de fonctionnement de ce vérin correspondant à la sortie progressive de sa tige 11.The control of these successive cycles is advantageously made automatic by making the tool comprise an appropriate pressurized fluid distributor and a device suitable for measuring the tension applied to the
Lorsque la valeur finale de traction T est atteinte, on ancre sur le bloc 3 le tirant tendu 1 de toute manière désirable.When the final value of traction T is reached, the
A cet effet, on a recours par exemple à une mâchoire 40 analogue à celles décrites précédemment, c'est-à-dire comprenant :
- des plaquettes intermédiaires 41 présentant chacune une portion centrale interposée jointivement entre les rubans 2 et deux portions terminales transversalement débordantes reposant sur le bloc 3,
- deux coins prismatiques 42,
- un cadre 43 propre à coagir avec les coins 42,
- et un vérin V₄ comportant lui-même un cylindre 44 solidaire de l'empiètement 8 et un piston 45 prolongé vers le bas par une tige 46 propre à prendre appui contre le cadre 43, ledit vérin V₄ étant desservi par des canalisations d'admission et d'évacuation de fluide sous pression 47,48.For this purpose, use is made, for example, of a
- two
a
- And a cylinder V₄ itself comprising a
L'ancrage est alors réalisé en activant le vérin V₄ dans le sens qui sollicite de façon irréversible le cadre 43 vers le bas.The anchoring is then carried out by activating the cylinder V₄ in the direction which irreversibly biases the
Cet ancrage pourrait être réalisé de toute autre façon désirable, par exemple en serrant le tirant 1 entre deux barreaux rigides sollicités l'un vers l'autre à l'aide de systèmes boulons-écrous à haute résistance, l'ensemble de ces barreaux et de ces systèmes encadrant l'empilement de rubans 2 et plaquettes d'entretroisement 41 à serrer.This anchoring could be achieved in any other desirable way, for example by tightening the
L'ancrage ainsi décrit prend à son tour le relais des deux mâchoires de serrage 20 et 30 pour le maintien de la tension T dans le tirant 1 de sorte que l'on peut desserrer ces deux mâchoires (figure 4), puis dégager l'ensemble de l'outillage de tension, lequel peut être utilisé pour mettre en tension un autre tirant.The anchoring thus described in turn takes over from the two
En suite de quoi, on obtient un dispositif de mise en tension dont la constitution et le fonctionnement résultent suffisamment de ce qui précède.As a result, a tensioning device is obtained, the constitution and operation of which result sufficiently from the above.
Ce dispositif présente de nombreux avantages par rapport à ceux antérieurement connus et, en particulier, les suivants :
- les différents serrages exercés par les mâchoires sur les tirants mettent en oeuvre des déplacements exclusivement transversaux des mors appliqués sur ces tirants, ce qui exclut tout recul et détente desdits tirants lors de ces serrages : la valeur maximum de traction obtenue à la fin de chaque course du vérin de traction peut ainsi être conservée,
- les mâchoires de saisie peuvent être facilement desserrées lors des cycles successifs et la tension désirée T peut être appliquée avec précision au tirant 1 du fait de la totale indépendance qui existe entre cette tension et les efforts de serrage desdites mâchoires de saisie,
- en jouant sur l'obliquité des faces planes mutuellement coagissantes des coins et des cadres, il est possible d'ajuster à volonté les forces de coincement à développer par chacun des vérins V₂, V₃ et V₄ pour engendrer des efforts de serrage déterminés et en particulier d'obtenir pour ces forces des valeurs relativement faibles.This device has many advantages over those previously known and, in particular, the following:
- the various tightenings exerted by the jaws on the tie rods implement exclusively transverse displacements of the jaws applied to these tie rods, which excludes any recoil and relaxation of said tie rods during these tightenings: the maximum value of traction obtained at the end of each stroke of the traction cylinder can thus be maintained,
the gripping jaws can be easily loosened during successive cycles and the desired tension T can be applied with precision to the
- by playing on the obliquity of the mutually coagulating flat faces of the corners and of the frames, it is possible to adjust at will the jamming forces to be developed by each of the cylinders V₂, V₃ and V₄ to generate determined clamping forces and particular to obtain relatively low values for these forces.
Comme il va de soi, et comme il résulte d'ailleurs déjà de ce qui précéde, l'invention ne se limite nullement à ceux de ses modes d'application et de réalisation qui ont été plus spécialement envisagés ; elle en embrasse, au contraire, toutes les variantes, notamment celles où le tirant à tirer ne se présenterait pas sous la forme de rubans parallèles, mais sous celle de câbles ou torons cylindriques, les mâchoires de serrage comprenant alors des mors de révolution radialement fendus entourant lesdits câbles ou torons, lesdits mors étant évidés par un alésage cylindrique, limités extérieurement par une surface tronconique, et propres à coagir avec des logements tronconiques complémentaires évidés dans des bagues axialement mobiles.As goes without saying, and as it already follows from the above, the invention is not limited in no way to those of its modes of application and embodiments which have been more especially envisaged; on the contrary, it embraces all variants thereof, in particular those in which the tie rod is not in the form of parallel ribbons, but in that of cylindrical cables or strands, the clamping jaws then comprising radially split jaws of revolution surrounding said cables or strands, said jaws being hollowed out by a cylindrical bore, externally bounded by a frustoconical surface, and adapted to interact with complementary frustoconical housings hollowed out in axially movable rings.
Claims (3)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT86402826T ATE62970T1 (en) | 1985-12-16 | 1986-12-16 | TENSIONING DEVICES BEFORE ANCHORING. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR8518596 | 1985-12-16 | ||
FR8518596A FR2591643B1 (en) | 1985-12-16 | 1985-12-16 | IMPROVEMENTS ON DEVICES FOR EXERCISING A TENSION ON A TENSION BEFORE ANCHORING |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0227546A2 true EP0227546A2 (en) | 1987-07-01 |
EP0227546A3 EP0227546A3 (en) | 1988-07-20 |
EP0227546B1 EP0227546B1 (en) | 1991-04-24 |
Family
ID=9325828
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP86402826A Expired - Lifetime EP0227546B1 (en) | 1985-12-16 | 1986-12-16 | Devices for stressing tendons before anchoring |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0227546B1 (en) |
JP (1) | JPS62156477A (en) |
AT (1) | ATE62970T1 (en) |
DE (1) | DE3678915D1 (en) |
ES (1) | ES2021604B3 (en) |
FR (1) | FR2591643B1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2650618A1 (en) * | 1989-08-01 | 1991-02-08 | Holzmann Philipp Ag | METHOD AND DEVICE FOR THREADING STEEL CABLES FOR BEAM STRESS BODIES IN CONSTRAINED CONSTRAIN CHANNELS |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN116119231B (en) * | 2022-12-30 | 2024-01-30 | 无锡中鼎集成技术有限公司 | Light stacker for storage |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1082394B (en) * | 1952-08-04 | 1960-05-25 | Fritz Leonhardt Dr Ing | Device and method for anchoring rods, especially for prestressed concrete |
US3090598A (en) * | 1960-02-09 | 1963-05-21 | Max Paul & Sohne Maschinenfabr | Hydraulic jack for the prestressing of concrete reinforcements |
FR2063477A5 (en) * | 1969-10-17 | 1971-07-09 | Marseille Grands Travaux | |
FR2384594A1 (en) * | 1977-01-12 | 1978-10-20 | Trouvay & Cauvin Ets | EXTRACTOR FOR EXTENDED-SHAPED PARTS, IN PARTICULAR HEAT EXCHANGER TUBES |
EP0098927A2 (en) * | 1979-08-13 | 1984-01-25 | RESTRA-Patentverwertung GmbH | Device for anchoring the end of at least one rod of fibrous composite material used as a tensioning member in prestressed concrete constructions |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2763464A (en) * | 1952-07-26 | 1956-09-18 | Leonhardt Fritz | Apparatus for anchorage of concrete reinforcements |
JPS6058349B2 (en) * | 1981-08-14 | 1985-12-19 | 建設基礎エンジニアリング株式会社 | Tension method and equipment for PC steel materials |
-
1985
- 1985-12-16 FR FR8518596A patent/FR2591643B1/en not_active Expired - Lifetime
-
1986
- 1986-12-16 AT AT86402826T patent/ATE62970T1/en not_active IP Right Cessation
- 1986-12-16 ES ES86402826T patent/ES2021604B3/en not_active Expired - Lifetime
- 1986-12-16 JP JP61299796A patent/JPS62156477A/en active Granted
- 1986-12-16 EP EP86402826A patent/EP0227546B1/en not_active Expired - Lifetime
- 1986-12-16 DE DE8686402826T patent/DE3678915D1/en not_active Expired - Lifetime
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1082394B (en) * | 1952-08-04 | 1960-05-25 | Fritz Leonhardt Dr Ing | Device and method for anchoring rods, especially for prestressed concrete |
US3090598A (en) * | 1960-02-09 | 1963-05-21 | Max Paul & Sohne Maschinenfabr | Hydraulic jack for the prestressing of concrete reinforcements |
FR2063477A5 (en) * | 1969-10-17 | 1971-07-09 | Marseille Grands Travaux | |
FR2384594A1 (en) * | 1977-01-12 | 1978-10-20 | Trouvay & Cauvin Ets | EXTRACTOR FOR EXTENDED-SHAPED PARTS, IN PARTICULAR HEAT EXCHANGER TUBES |
EP0098927A2 (en) * | 1979-08-13 | 1984-01-25 | RESTRA-Patentverwertung GmbH | Device for anchoring the end of at least one rod of fibrous composite material used as a tensioning member in prestressed concrete constructions |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2650618A1 (en) * | 1989-08-01 | 1991-02-08 | Holzmann Philipp Ag | METHOD AND DEVICE FOR THREADING STEEL CABLES FOR BEAM STRESS BODIES IN CONSTRAINED CONSTRAIN CHANNELS |
Also Published As
Publication number | Publication date |
---|---|
FR2591643A1 (en) | 1987-06-19 |
ES2021604B3 (en) | 1991-11-16 |
EP0227546A3 (en) | 1988-07-20 |
FR2591643B1 (en) | 1990-11-02 |
EP0227546B1 (en) | 1991-04-24 |
ATE62970T1 (en) | 1991-05-15 |
JPS62156477A (en) | 1987-07-11 |
JPH0481028B2 (en) | 1992-12-22 |
DE3678915D1 (en) | 1991-05-29 |
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