US2554755A - Method for binding cylindrical concrete work and apparatus for executing this method - Google Patents

Description

y 1951 R. G. SECHAUD ET AL ,7

METHOD FOR BINDING CYLINDRICAL CONCRETE WORK I AND APPARATUS FOR EXECUTING THIS METHOD Filed Dec. 27, 1946 a Sheets-Sheet 1 IN elvro 8 SheetsSheet 2 1': vs: T0 R V 4.)4.W v-anee Ma 5 M,M mm

AND APPARATUS FOR EXECUTING THIS METHOD R. G. SECHAUD ET AL METHOD FOR BINDING CYLINDRICAL CONCRETE WORK May 29, 1951 Flled Dec 27, 1946 May 1951 R. G. SECHAUD ETAL 2,554,755

METHOD FOR BINDING CYLINDRICAL CONCRETE WORK AND APPARATUS FOR EXECUTING THIS METHOD Filed Dec. 27, 1946 8 Sheets-Sheet 5 v INveJy-r I RKLWv-dmfimfi 3 Low m, Mvmw May 29, 1951 R. G. SECHAUD ETAL METHOD FOR BINDING CYLINDRICAL CONCRETE WORK AND APPARATUS. FOR EXECUTING THIS, METHOD Filed Dec. 27,-1946 a Sheets-Sheet 4 AND APPARATUS R EXECUTING THIS METHOD Filed Dec. 27, 1946 y 29, 1951 R. G. SECHAUD ET AL I 2,554,755

METHOD FOR BIND AL. CONCRETE WORK CYLINDRIC 8 Sheets-Sheet 5 INVQNr a R. G. sEcHAuD ET AL METHOD FOR BINDING CYLINDRICAL CONCRETE WORK May 29, 1951 2,554,755 AND APPARATUS FOR EXECUTING THIS METHOD Filed Dec. 27, 1946 8 Sheets-Sheets y 1951 R. G. SECHAUD ETAL 2,554,755

METHOD FOR BINDING CYLINDRICAL CONCRETE WORK AND APPARATUS FOR EXECUTING THIS METHOD 8 Sheets-Sheet '7 Filed Dec. 27, 1946 I N v e T-o R Rqksw L mmaawur 6 mm, M, M v- 40% M y 1951 R. G. S-ECHAUD ET AL 2,554,755

- METHOD FOR BINDING-CYLINDRICAL CONCRETE WORK .AND APPARATUS FOR EXECUTING THIS METHOD Filed Dec. 27, 1946 8 Sheets-Sheet 8 I ollltllaprllnrlpllllilll/ INtLQNTOR Kn. wvwnlahwi B MM, @414,

Patented May 29, 1951 METHOD FOR BINDING CYLINDRICAL CON- CRETE WORK AND APPARATUS FOR EX- ECUTING THIS METHOD Roger G. Schaud and Adolphe N. F. Metz,

Paris, France Application December 27, 1946, Serial No. 718,718 In France January 9, 1946 3 Claims. (Cl. 254-51) 1 It is a well known fact that it is possible to bind certain structures such as pipes under pressure or reinforced concrete containers for increasing their resistance. Among the solutions already proposed, some contemplate using outer.

hoops constituted for instance by cables which are tensioned by drawing them with some force away from the periphery of the structure, wedges being then inserted in the gap thus provided. It is possible to increase in this manner the tension at several points of the same hoop and to obtain through the latter a fastening stress which is practically constant throughout the periphery of the hoop. It is well known, as a matter of fact, that one of the chief hindrances met with in the tensioning of hoops round a circular piece of work consists in a considerable reduction in tension due to the friction of the hoop on the wall of the piece of work when action is applied at various points of the hoop.

The procedure disclosed offers considerable advantage as it allows making with concrete a circular piece of work without any preliminary straining, hoops being then fitted and the work is subjected to stresses provided by a preliminary compression. But in conventional processes, the binding hoops are arranged without any preliminary tensioning and even with a 1 certain slack due to a lack of flexibility of the cables which require for their tensioning apparatuses that are very powerful and have important strokes, that are in other words heavy and bulky so that the use of such apparatuses may be sometimes difiicult. Moreover when cables are used, one is led either to form closed loops by interconnecting the cable strands or else to use spiral turns and to anchor separately each of the two ends thereof. The tensioning of the hoops is liable to overcome the anchoring means and to make this tensioning system inoperative.

Our invention has for its object a method for binding concrete pieces of work of cylindrical shape and of large diameter. This method comprises after casting the piece of work, in binding the latter with a series of pairs of cables the length of which is slightly greater than that of the periphery of the structure, subjecting each pair to a first tensioning operation adapted to directed in one way being fitted between the two others directed in the other way, anchoring after applying these stresses the pairs of cable ends by urging them against one another and then exerting in the portion of the pair of cables diametrically opposite to the anchoring zone of the ends of the cables a tractional stress drawing the cable away from the piece of work and lastly inserting thewedges inside the gap thus produced. If care is taken moreover to arrange in staggered formation on the piece of work the anchoring points of the successive pairs of cables and also by way of consequence the portions diametrically opposite thereto, there is obtained thus a circular piece of work subjected to a preliminary compression in which the preliminary compression stresses due to the tensioning of the hoops is used to an optimum extent.

Our invention has also for its object apparatuses which are particularly suitable for performing the above method and which allow industrial applications. Said method according to our invention is particularly applicable to the binding of forced fiow pipes of large diameters up to several meters, to cables having a diameter of several centimeters and to lengths of work which justify the use of the intricate apparatuses performing a succession of a large number of tensioning operations.

In the practical application of the method, there are provided v two carriages adapted to carry the workers along the piece of work. The first carriage allows a temporary tensioning and a temporary wedging of the cables while the second carriage furthers the final tensioning of these cables and their anchorage.

We have given out hereinafter a description corresponding to accompanying drawings and oifered by way of examples and by no means in a limiting sense and this description will provide a clear disclosure of the manner of carrying out urge it tightly against the piece of work, pro-,

our invention. In said drawings:

Fig. 1 is a diagrammatic perspective view of a pair of cables provided with means for exerting a traction on said cables. 7

Fig. 2 is a cross-section of a pipe over which moves the first carriage used for positioning the different pairs of cables on the pipe.

Fig. 3 is a side-view of said carriage.

Figs. 4 and 5 are respectively an elevational and a cross-sectional view of a tractional hook adapted to applya first tensioning .to the cable.

Fig. 6 is a perspective view of a temporary wedging member.

Fig. 7 is an elevational View of the temporary wedging of the anchoring end pieces of the cables.

Fig. 8 is a cross-section of the pipe with the second carriage used for the final tensioning of the pairs of cables.

Fig. 9 is a side-view of this latter carriage.

Fig. 10 shows the final tensioning of the ends of the cables by means of jacks.

Fig. 11 is a detailed plan-view of these tensioning means, the upper half showing the said means before tensioning and the lower part showing them after tensioning.

Fig. 12 is an elevational view of the system of jacks used for exerting a traction on the portion of the pair of cables which is diametrically opposite to the anchoring of its ends.

Fig. 13 is an elevational view at right angles with Fig. 12.

Lastly, Figs. 14 and 15 are cross-sectional views of the molds used for embedding therein cables inside concrete when the tensioning operations are at their end.

Referring to Fig. 1, the cables I and I of the pair of cables illustrated form two spiral turns wound in opposite directions; The ends 2 and 2 of these turns are held inside the socket 3 madeof metal and showing an inner recess 4 of frustoconical shape wherein the ends of the cables are anchored, after opening out, through the casting of a material adapted to set. On the other hand the ends 5 and 5 are arranged on either side of the ends 2 and 2' and are held fast in a further socket 6 including two frustoconical recesses 1 and I for anchoring the latter ends. Each of the sockets 3 and 6 includes lugs 8 allowing the application of tensioning devices and a base plate 9 adapted to provide for their wedging.

In the zone diametrically opposite to the ends 2 and 5 is arranged a pusher member ID assuming the shape of a strap and over which are guided the cables I and I, said pusher member including a base plate 11 and lugs 12 for tensioning purposes.

The binding of a circular piece of work by means of pairs of cables such as disclosed is performed in principle in the following manner:

The pair of cables being tightly applied around a diametrically predetermined cross-section of the piece of work to be bound, possibly through a preliminary tensioning kept up by a temporary Wedging, we begin exerting on the sockets 3 and 6 a tractional effort directed according to the arrows F and F. When these stresses reach a predetermined limit, thesockets are held against one another for their mutual staying by means of a compressed Wedge inserted between the bases 9 of the two sockets facing one another.

By reason of the friction of the cable against the piece of work, the tension decreases along the cable in accordance with a well known law and therefore its value in the zone diametrically opposite to its ends is substantially reduced. This reduction in tension is made up for by a traction G exerted on the pusher member 10.

It is immediately apparent that the winding in opposite directions of the turns formed by the cables I and I" and the arrangement of their ends allows the cables to be subjected to opposite stresses located in the same plane, i. e. it is possible to use tractional apparatuses developing stresses which do not produce a torque detrimental for the stability of the apparatus.

The application of the abovev disclosed principles will be described hereinafter with reference to accompanying drawings which show the binding operations for a forced flow pipe of large diameter.

The pipe I3 (Figs. 2 and 8) is cast with ordinary reinforced concrete and rests on the ground through a longitudinal shoe I4 inside which are provided oval or flat tubes or the like passageways I5 for the binding cables. When this :pipe is finished and the concrete has acquired a certain rigidity, the binding operations are begun first with the carriage I6 (see Figs. 2 and 3). This carriage includes wheels with solid beads I! ensuring its easy motion over the upper part of the pipe and it is guided through two angle bars I8 which may fit over a series of armatures I9 provided therefor at the upper part of the pipe and passing out of the wall of the latter.

The carriage I6 includes an upper gangway 20 and lateral gangways 2| and 22 which may be provided with footrests 23 adapted to make up for the generally considerable slope of the pipe. Each side of the upper gangway is provided with .a pair of jacks 24 adapted to act on the chains 25 and therethrough on the traction member 26 which will be described with reference to Figures 4 and 5. In order to make up for the tractional stresses exerted by these jacks, the carriage is provided with adjustable tie-beams 27 which prevent its rocking. These tie-beams engage the pipe through looped pairs of armatures 28 of which a further use will be disclosed hereinafter. Lastly, the carriage I6 is provided with guiding means 29 adapted to further the accurate posi tioning of the pairs of cables, said guiding means being located underneath the lateral gangways 2| and 22. For greater clearness, we have shown in the drawings only one of the different parts, such as jacks, tie-beams, guiding members and the like corresponding to the pairs of cables anchored to one side of the pipe.

The carriage being suitably positioned and held by retaining winches or the like anchorages, the pairs of cables provided with a socket 3 are directed in th immediate vicinity of the pipe, for instance through a temporary track arranged parallel to said pipe. These cables are wound round the pipe and pass through the pipes I5 after positioning of the pusher member I0 and the socket 3 is wedged by means of a temporary stop illustrated in Fig. 7 and the chief component part of which is illustrated in perspective view in Fig. 6.

It is apparent from the last mentioned Fig. 6 that the stop includes a sort of casing 30 of folded metal sheet one edge of which is reinforced by an iron strap 31 welded to said edge while its other end which is recessed at its upper part is also reinforced by an iron member 32 fitted to the edge of the casing and welded thereto. The lower part of the casing surface shows semi-circular recesses 33 inside which are secured semicircular parts 34 adapted to engage the looped armature couples 28 awaiting connection. As apparent from Fig. 7, the temporary stop system is finished off by a strap 35 located between the bearing base plate 9 of the socket 3 and the outer surface of the iron strap 3|. This latter strap is simply adapted to allow an easy dismantling of the system; as a matter of fact when the strap is removed, the bottom of the casing 30 may move between the bases 9 facing one another. The casing 30 secured over the pairs of armatures '28 through the threaded rods 36,, cooperating winged nuts 38 and a plate 31 through which said rods pass.

When the pair of cables is stopped by the. abutment of its socket 3 against the casing 38 and the strap 35, it is possible to exert in the zone:

near the horizontal diametrical plane a vertical tractional stress by means of the jacks 24, this stress urging the cables against the pipe while tensioning the same. The ends 5 and 5' of the pair of cables are then engaged underneath the casing and occupy a substantially vertical position shown in dotted lines in Fig. 2, which allows a convenient and accurate positioning of the socket 6. When the socket is secured,,the cables are folded over the pipe and the socket 6 is held in contact with the iron member 32 through thin wedges such as 39 (Fig. 7). V

During this operation, the positioning of the cables is made easier through the presence of the guide members 29 suspended under the gangways 2|. The traction exerted by the pair of jacks 24 is transmitted to the cables I and I through two clutches one of which is illustrated in Figs. 4 and 5, both clutches allowing retaining the contact between the cable and the pipe while drawing simultaneously and independently on the two cables and I; this result is obtained. by means of clutches including a stationary jaw parallel to the direction of the tractional stresses and a movable jaw adapted to hold the cable against the stationary jaw on which the traction is exerted.

The two clutches are similar and symmetrical like the two hands of a person and they include a frame 40 extending in the direction of the stresses and folded at its lower part for forming the stationary jaw 4|. The movable jaw 42 cooperating with the stationary jaw 4| is free to move in its recess and it is subjected to the action of a cam 43 pivotally secured at 49 and fast with a lever arm 44 which may be controlled through a double traction rod 45 the ends of which are fitted over the end of the lever 44 and over the end of the frame 40. The axis 48 connecting the end of the rods 45 to the strap 41 to which is secured the tractional chain, is adapted to slide inside the elongated slot 46 provided in the frame 40. A traction exerted along the axis of the cables on said strap fastens thus the latter between the stationary jaw and the movable jaw. i When the pairs of cables have been temporarily stopped as described with reference to Figs. 2 and 3, we proceed with their final tensioning. It is convenient to this end to use a carriage similar to that illustrated in the preceding figures and designed in a slightly-different manner. In practice the two carriages may follow ,one another over the pipe at an interval of about ten meters and while the first carriage serves for the temporary tensioning, thefinal tensioning may be performed by other workers operating from the second carriage. Said second carriage illustrated in Figures 8 and 9 includes in addition to gangways, wheels and guiding and holding members similar to those of the first carriage, a pulleyblock 5| at the upper part of the carriage; said pulley-block moves along a single rail 52 for handling the apparatuses adapted to tension the ends of the cables and furthermore at the lower part and underneath the lateral gangways there are provided, devices 53 controlling the apparatuses acting on the pusher members Ill.

The devices acting on the ends of the cables are illustrated at 54 and 55 in Figures and 11. Each of them includes a horseshoe frame 56 or 5! forming a balance-beam and carrying at its ends hydraulic jacks 58. To allow the hooking of these devices on to the pulley-blocks 5|, we have provided trunnions 59 defining an axis passing nearthe center of gravity of said devices and to which may be secured a sling taken up by the pulley blocks considered.

Each of the frames 56 and 51 includes shoulders 60on which bear the lugs 8 of the sockets 3 and 6. In order to provide a perfect securing of said sockets to the frames 56 and 51 and thereby to hold the devices 54 and 55 fast, we lock through the trapezoidal keys'6l and 62 inserted in opposite directions the head of each socket 3 and 6 against the inner surface of the frames 56 and 51.

The hydraulic jacks 58 stay one another by means of the rests 63 shaped as triangular prisms resting freely on the pipe I 3. Now, by feeding simultaneously the jacks 58 with liquid under pressure through pipes 91, for instance by means of a pump not illustrated and carried by the carriage, the two sockets 3 and 6 are moved apart and'tension the cables I and I to a considerable extent. During this operation, the temporary stop constituted by the casing 36 and the strap 35 is released. The projecting part 96 of each jack 58 is screwed and carries a safety nut 64. After extension of the jacks under hydraulic pressure, these nuts may be screwed freely till contact with the cylinder of the jack 58. Thus the safety nuts 64 allow retaining the tension obtained by the jacks even in case of a loss of hydraulic pressure, it is possible to perform without any risks the dismantling of this temporary stop. It is then sufficient to replace the casing 38 and the strap 35 by a mass of very dry concrete 65 which is tamped inside the space comprised between the base plates 9 of the sockets and lateral walls 68 inserted subsequently between the lateral faces of the sockets and the cylinders of the jacks 58 as shown in the lower part of Fig. 11 and formed for instance of sheet iron. Thus the looped reinforcements 28 which held the casing 30 are embedded in said tamped concrete, so that the tamped concrete block is reinforced and secured to the pipe.

When the concrete has set and has become hard, it is possible to dismantle the tensioning apparatuses and to remove the keys 6| and 52. When operating with high grade cement, it is possible to obtain a quite satisfactory hardening after a lapse of time of about 24 hours.

We then proceed with the tensioning of the lower part of the hoop by acting on the arrangement illustrated diagrammatically at 53 in Fig. 8. The chief component of this arrangement is constituted by the jacks illustrated in Figs. 12 and 13. and carried at the end of a balance beam 68 provided at its other end with a counterweight 59, said balance beam being pivotally secured at "iii to the end of a rod ll of adjustable length. The position of the jack 12 may also be adjustable along the balance beam 68 by means of the adjusting wheel 13 providing for the screwing or unscrewing of a threaded rod 14 carrying the jack 12 at its other end.

The jack 72 includes a jack proper 15 pro vided with trunnions H: to which'are pivotally secured the tractional rods or stays ii which engage through pin 18 the lugs l2 on the pusher member 13. The piston of the jack ends on the other end with head l5 forming a swingbar which bears through the ball on stirrups or staples 8| passing over the cables and I, Resilient blades 82 connect permanently the stirrups to the head 19, so as to prevent the ball 80 from falling out. These balls form a kneejoint allowing the tractional effort exerted by the jack on the cables to be equilibrated while making up for the superficial inequalities due to the bearing of the stirrups on the pipe. Like the jack 58 described hereinabove, the jack i is provided with a safety nut 83 which is screwed down for compelling it to follow the displacement of the piston. The jack system as a whole is suspended to the trunnions 84 of the strap 85 (as shown in Fig. 8) which forms the ends of the balance beam 68.

The balancing and the adjustment afforded by the devices 53 provide in spite of the weight of the jack 12 perfect registering between the opening in the traction rod I! and the openings in the lugs 12 so as to allow an easy insertion of the pin 18.

When the pusher member It has been removed away from the pipe is, we insert inside the gap 86 located between the base plate H of the pusher member and the pipe, wedges which maintain the cable tension thus obtained. These wedges may be constituted of very dry cement mortar which is tampecl into the gap. This allows a very rapid setting of the cement in a time which does not extend substantially beyond ten hours.

When the hoops have been tensioned, it is of advantage to protect them with a concrete filling forming a sort of ring round the pipe. Figures l4 and show an advantageous form, of a mold adapted for use to this purpose in order to reduce to a strict minimum the amount of filling mortar required. This mold includes channels 81 having a U-s'haped section matching the circular shape of the pipe. The edges of the channel are provided with yielding strips 88 held at intervals by bolts 89 through suitable lugs or shaped members 99. The channels 81 are fastened against the pipe l3 by means of threaded rods 91 carrying nuts 92 and whose end is screwed at 93 into members 94 engaging the cables I and I. When these cables are near one another, said members 94 assume the shape of straps as illustrated in Fig. 14. On the contrary, when these cables are comparatively far from one another, the members 94 may be simply constituted by a small element of fiat iron held underneath the cables I and I.

In both cases the members 94 are located over or between the cables and engage the latter with a slight rotary movement.

If care is previously taken to fill the pipes or passage-ways l5 with mortar, the mold constituted by a series of channels 81 is set in position and said mold remains open through its upper part. Concrete is then cast in the ring shaped space thus formed through a rubber tube opening into the lower part of the mold and raised as the mortar rises inside the mold. The concrete being cast, the channels are removed by unscrewing the nuts 92 and recovering the threaded rods 9| which are acted upon for instance through their square shaped ends 9L1 which allows unscrewing them. Thus only the members 94 remain lost inside the concrete.

Obviously many detail modifications may be brought to the method described without departing from the scope of our invention.

iii)

What we claim is:

1. In an apparatus for hooping large diameter concrete pipes by means of a pair of cables the overlapping ends of which are provided with sockets, a pair of jacks, each comprising a horse shoe frame carrying on its ends two parallel jack cylinders, means for securing a socket to said frame, a plunger in each jack cylinder; two members of triangular cross=section adapted to rest freely on the work to be hooped on either side of the pair of cables in the vicinity of the crossing of their ends and on the lateral faces or which bear the external ends of said plungers; and means for imparting equal fluid pressures in the jack cylinders.

2. A method for hooping a pipe, comprising binding the pipe with pairs or cables having a length slightly greater than the circumference of said pipe and the ends of which overlap, two ends directed one way lying between the two ends directed in the other way; securing sockets on both pairs of ends, exertin on the two pairs of ends through the sockets high tractional stresses in opposite directions by expanding means inserted between the lateral sides of said sockets and the lateral faces of two members of triangular cross-section adapted to rest freely on the pipe to be hooped on either side of the pair of cables in the vicinity of the crossing of their ends, staying both sockets against one another and retaining the obtained tension of the cable by tamping hardening material on the pipe between the opposite faces of said sockets, and removin said expanding means and triangular members.

3. In an apparatus for hooping large diameter concrete pipes by means of a pair of cables the overlaping' ends of which are provided with sockets comprising lateral projections, a pair of jacks, each comprising a horseshoe frame carrying on its end two parallel jack cylinders and shoulders for hearing said lateral projections, at least a wedge inserted between the middle part of said horseshoe frame and said sockets, two members of triangular cross-section adapted to' rest freely on the work to be hooped on either side of the pair of cables in the vicinity of the crossing of their ends and on the lateral faces of which bear the external ends of said plungers, and means for imparting equal fluid pressures in the jack cylinders. V V

ROGER G. SECHAUD. ADOLPI-IE N. F. METZ.

REFERENCES CITED The following references are of record in the fil'eof this patent:

UNITED STATES PATENTS Number I Name Date 772,117 Winslow Oct. 11, 1904 903,911}; Steiner Nov. 1'7, 1908 915,555 Conner Mar. 16, 1909 1 ,119,733 Schulte' Dec. 1, 1914- 1,281,201 Peterson Oct. 8, 1918 1,781,699 Parmley Nov. 18, 1930' Aug. 1, 2,348,765 Trickey May 16, 1944 2,359,446 Scudder Oct. 31, 1944 2,312,723 Jasper Apr. 3, 1945

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