US1726414A - Method and apparatus for grouting concrete structures - Google Patents

Description

l 1,726,414 METHOD AND APPARATUS FOR GROUTING CONCRETE STRUCTURS l 1. L. sAvAG Aug. 27, 1929.

- 5 Shets-Sheet Filed Jan. 16, 1928 u uw...

Aug. 27, 1929.

J. SAVAGE 1,726,414

AND APPARATUS FOR G'ROUTINGv CONCRETE STRUCTURES METHOD led dan 1928 3 Sheets-SheetA @HHHHH Hu:

, .n.HHHHHhH@ n Aug. 27, 1929. I .1. 1 SAVAGE 1,726,414

v METHOD AND APPARATUS FOR GROUTING CONCRETE STRUCTURES Filed Jan. 16, 1928' 3 Sheets-Sheet 5 dm mdf, formy;

Patented A ug( 27, 1929.

Jona L. savaenor nnnvnn., comme.

Application led Inmary 16,'.1928- Serial No. 247,045Q

lMy invention relates to new system' and apparatus for introducing suitable grouting material into contraction joints or construction joints of concrete structures 41n the cours'eof their erection, or, after their com pletion', and to avoid the attendant ditiicul ties, uncertainties, and'v heavy expense which the use of the methodsand equipment at present available'entail. i

. It is wellknown to art that v'concrete contracts in setting and particularly when subjected to low temperatures and that any long concrete structure will develop transverse cracks at frequentintervals throughout its length as a` result of this contraction.: It is possible to controltlie location and extent of these contraction cracks by providing frequent. jointsin the concrete which in the terminology ofthe art arecalled construction joints. or preterably contraction joints. While these contraction joints are necessary and desirable for the purpose of pre-determining the location and direction of the contraction cracksl they introduce planes of weakness through Ythe concrete structure which are undesirable Afor structural reasons as compared with a j monolithic structure. In order to minimize this structural defect and'to strengthen these planes of weakness it has'beqome the practice of engineers to require thatall contraction joints in important concrete dams and other massive structures be filled under pressure with Portland cement grout or other cementingmateriah' at' -a time when the structure is at the -lowest temperature 'and the contraction joints have the maximum opening. By this means the separate -parts or units ofthe structure are cemented together,',orming `practically a' monolithic structure. The grouting of vertical contraction joints in this manner is `of particular importance in the case ot concrete arch vdamswhere `it is essential to fill the joints with a strong grouting material in order to forma continuous arch cylinder to receivev `tl1e arch thrust, and transmit it into the'l canyon walls throughthe abutments at each end of the dam.

Inorder that all'contraction joints in a concrete structure may be-illed up in such a manner that the t'wof closely adjoining parts or units may be bonded integrally together, some lcontinuously connected conduit system must be'pro'vided that will form the passageway thpse skilled in ai@ by which the cementing,L fluidl or grout can be dischargedunder pressure 4 i'nto the" contraction joints between each adjolnlng' pair "of concrete units.

My inventi'orrcontemplates in the accomplishment fof-these results the use of any lsystem of operative procedure, and any arrangement of pipes or -conduits that are embedded in the body of the concrete at a distance far enough back from the formed face to provide convenient and rigid attachment to the forms and to insure their proper protection by `embedment in the concrete, and any system or 'arrangement of pipes, which provide closed conduits for leading the ceinenting iuid or 'grout to predetermined -1 points along the'contraction joint-between dltl'erent units of a concrete structure.

In'the accompanying sheets of drawings I have illustrated my invention applied to a'large dam, butit will be understood that the specific form of its application as herein illustrated is illustrative of the principle of the invention, and is capable of being varied 'to suit the type of. structure in which vit is.

to be employed or utilized.

The objects' of my invention are:

First; to providea conduit systemv and i apparatus 'for gronting the construction joints orcontraction joints which will occurV between different parts of a concrete structure. of large dimenslons such as a massive concretedam or retaining wall 11i-which one or more parts or units ofl the structure are built up progressively to partial or full height and allowed to harden in advance' of the other arts or units .of the structure which are': ater poured against the formed Afaces ofthe partsor units vfirst built;

j Second; Vto provide a conduit system and apparatus for 'grouting' concrete structures whereby the shrinkage and temperature cracks developing between the .different parts or -unitsof the structure, which have been poured at different times, are grouted under pressure` with cement grout and strongly bonded to form them into one integral whole.

Third; to provide a simple, inexpensive, easily erected groutingsystem of suiicently rigid construction to remain in place while the concrete structure is; being poured and Vwhich will be eiective lin thoroughly filling all contraction joints when the pressure groutin operation is performed.

Fourt to-provide a conduit supplying, distributing and introducing system and apparatus which can' be progressively installed unit by unit as the forms for each successive vertical increment of a large concrete unit are erected upon and above the concrete previously poured and seasoning, and thereby avoiding any necessity of following any special erection and construction programs from'those which would be followed were a grouting mechanism not used.y

Fifth; to provide a plurality of conduits communicating independently between predeterminedly positioned points of entry into the space to be grouted or filled, and the outside source of supply where the grouting material is introduced under pressure, with said plurality of communicating conduits entirely embedded and contained within the concrete first poured and seasoned, and thereby effectually protected from injury during the period of construction of the adjacent concrete units on either side.

I attain these objects by the mechanism I and systemillustratedin the accompanying drawings, in which:

Figure 1 is a vertical sectional view, showing a fragment of the wood form or lagging for confining a unit or part of the concrete structure, in connection with a grout supplying header pipe (l), a riser pipe (2), a horizontal nipple (6), and a conduit outlet box (7) through which grout is forcedinto the contraction joint.

Figure `2 is a vertical sectional view -of a portion of a finishedv concrete unit, showing the embedded grout supplying pipes and conduit outlet box and a similar conduit outlet box secured on the embedded outlet box. Figure 3 is a vertical sectional view through' portions of two finished and hardened concrete units, showing the contraction joint (26), between the units, and the separated conduit. outlet boxes through which the grout can flow froml the supply pipes to the contraction joints.

Figure 4 is a front view of'one of the con-4 duit outlet boxes.

Figure 5 is a side .view partlyin section of a structural concrete unit, showing the grout supplying header pipe (l), embedded therein, the riser pipes l(2), connected therewith and the conduit outlet boxes (7) which are connected by short pipes or nipples (6) with the riser pipes', the unit having the appearance it presents when ready .for the pouring of an adjoining unit or part ofthe concrete structure. r

4Figures 6 and 7 vare plan Niews of two wooden forms confining twov concrete. units or parts of the concretestiucture, showing the embedded grout' conveying pipes connected to the forms, the two units being separated by a space to receive a third unit after the first and second units have hardened.

Figure 7A is a plan view of a fragment of one of the concrete units,` showing the con-- figuration of one-of the side faces thereof.'

Figure 8 is an end view showing the manner of connecting the two sets of riser pipes with a common header pipe.

Figure 9 is a plan view of a fragment of 7 a concrete-holding form, showing a metal strip secured to one side thereof'which later closes the contraction gap between two adjoining concrete units.

Figure l() is a plan view of a portion of 7 a hardenedXinit, and the gap-closing strip partially em edded therein. Figure 11 is a plan view of fragments of two hardened units, showing the contraction gap between them, and the gap-closing strip 8 partially embedded in each unit; and

Figure l2 is a side view, showing the upper portion of the unit illustrated in Figure 5.

Referring now to the drawings the-appa- 5 ratus I employ to accomplish the ob-jects of my invention consists of a header pipe 1,' which is placed horizontally or approximately so at the lower confines or bottom edge portion of each of the contraction lagging form A, which will be the faceof the concrete unit or block of concrete alongwhich thev contraction joint is to occur to the top surface of the completed structure. i l

In the preferred construction of the header and riser pipes l, 2, and 2A respectively, the header pipe .is preferably l inch in diameter and riser pipes are preferably onehalf inch in diameter, and are made of any l predetermined length, and the sections are connected by 'Ts 5 and 5A respectively. To the Ts 5, are threaded nipples 6, which project horizontally from the Ts, and to the outer end of each nipple 6 is secured a dish shaped cup 7, that is provided with a circular flange 8, and the cup 7 is'adjustably secured on the end of the nipple 6 by lock nuts 23 and 24, as this arrangement allows the cup to be adjusted on the nipple 6, so

that the face 8, of its flange, can be screwed up tight against the inside surface of the inner face 8 of the form A.

My invention contemplates the securing of the flange 8, of the cup up against the inside face 3, of the form A, by any suitable means; but I preferably secure it tothe inside face of the form with nails or similar suitableattachments substantially as shown in the accompanying drawing at B. I pref'- erably have the vertical riser pipes 2 and 2A made in a number of units whose equal lengths each is slightly shorter than the desired -vertical distance between the horizontally-positioned nipples 6 'that communl cate with the dish or cup pieces 7 and 7A which are fastened to the inner face 3 of the walls of the forms A and their opposing ends are attached to the horizontal nipples'6, whose opposite ends are screwed into `reach the final completed height of the strucx In addition to the support afo'rded ture. the vertical riser 2 by the horizontal nipple 6 connecting to the cup or dished piece 7 ,I

place a double wire 11 around the riser pipe' 2, above the T 5, and pass these wires through the wall of the form A, and tie their protruding ends firmly together. I then insert a suitable nail 12 or bar. through the parallel pair of wires about midway between the form and the riser pipe and by turning-the nail or bar in a plane at right angles to the commonaxis of the wires, twist the wires around each other tightly, and this twisting causes 'atension to exist in the wires, which pulls against the riser pipes, and this .pull is resisted by the .horizontal nipple 6, connecting the riser 2 to the cupped dish pieces 7 against the inside surface 3 of the wall of the form A, so that by means of the cupped piece 7, with its horizontal nipple 6, connecting it to the riser pipe 2, and the twisted wires 11 ypulling against this horizontal thrust resisting nipplel member 6, and the similar treatment of the other like units lin the same manner, make andcom- .prise a strong rigid structure for the purpose intended, which can be built up readily as fast asthe forms are erected, and 'will re- -main fixed in the predeterminedly selected and4 erected positions while `the concrete is poured into the-completed forms and thereafter as well. The header pipes I, are made up of sec-tions of pipe connected by T couplings 1A, the alternate T couplings having their center openings pointlng outward, andA to these lattep couplings are connected relatively short horizontal pipes 9, to the outer ends of which are attached either T couplings or elbows 9A, the elbows being shown in Figure 8, and to the elbows are connected the riser pipes 2A, made up of pipe sections ,and T couplings 5A, and to these couplings are connected nipples 6A to .which are connected flanged cups 7A similar to the cups 7 on'the nipples 6. The risers 2A are about nine inches to the outside of the risers 2,' and the cups 7A alternate with respectto the ositions of the cups 7 as clearly shown in Figure 5. The purpose of the double row of risers, will hereinafter appear.

.Two header pipes 1 extend along the opposite sides of veach unit 'of concrete to be made as shown in the plan view Figure 6, and a large number of riser ipes 2 and 2A, are connected `to the top of t esetwo header pipes 1, and to the horizontal pipes 9 respec-` tively, and are placed at any predetermined distance apart. Both ofthe header pipes and all of the. riser pipes 2 and 2A, are installed inside of the forms A, as soon as they are erected, for those units of the-structure which are to be pouredl first, and are positioned a reasonable distance back from the face 3y of the form A which produces ,y

the contraction joint face, so that whenvthe forms A are filled with concrete, the header pipes 1, and the riser pipes'2 and 2A, are completely surrounded and embedded within the concrete.

orm its border outline along its sides into n a continuous succession of corrugations 12A, the surface ofv each of which is preferably e ual in length, that is, the flat `straight sur ace 13 of the projecting portions of the corrugation are equal in ngth to the length of the flat straight surface 14 of the recessed portions of the corrugations, as shown in Figure 7, and this outline vof the border or boundary of each unit necessitates that thevform A be also built in this In lafying out a unit of concrete, I prefl erably corrugated outline and in its construction vertical posts 15 or studding is pl'aced'at the kintersecting of the parts of the form'A f f at its inside corners 16, and atthose vertical end portions 17 of the formA A, which prescribe the opposite outside 5 edges of the contraction joint in-'a vertical plane. I insert lbands of metal 18 or otherY suitable material having V-shaped folds 18-A along the central portion of. their widths, with their folded portion resting against the contracting joint forming faces of the forms which in this case would be lthe outside surface of the form A, the pur ose of these bands being to form a stop which will later prevent the grout from escaping from along the contraction` joint faces at the opposite corners 19 ofthe entire height of the unit.

The corrugations 13` and 14 in the form A, ofthe concrete units G and H of Figures 6 and7 that are opposite to each other form a continuous tongue and groove surface throughout practically their entire length;

and assuming that these two units G and H which aredefined by the opposite forms Ky and K1 of the unit G, and the opposite sides L and L1 of the form IjI, have been vpoured and have hardened, then by closing up the opposite ends M and M1 of the space N, this space or unit N can be poured, and when iso it is poured the concrete flows into the vertical groove members against the surfaces 14, that define the depth of these grooves; and this tongue and .groove construction of new units between hardened units results in thenew units being rigidly locked4 by these numerous tonguelike keys that enter the hardened units, against any possible movement whatever from down steam pressures that would fiow against its upsteam end, asl the units in dam construction are placed transversely across the length of the dam, but the units can be arranged in any other predetermined positions relative tol the length and breadth of other kinds of concrete work. v

After the concrete has been poured and has set, the forms are removed in the usual manner, and the form facing portions of the cup-shaped dished pieces are then exposed withv their flanged edges flush with the surface of the concrete and the ends of the nails which held and secured them to the forms are now left protruding from the concrete.

I now place another set of cups 19A, that are also provided with flanges 20Ath-at are identical in shape and size with those cups 7 that are now embedded in the concrete, against the faces of their flanges 8, and` by bending the protruding ends 21 of the nails B over the peripheral edge of this opposing cup member 19A, I secure them firmly in place against the cup pieces 7 carried by the concrete as shown in Figure 2.

Into the middle diameter or central portion of each of this second set of cup ieces, Il place or inse'rt a pipe nipple 22 into a threaded or unthreaded hole in the center of the cup piece provided for that purpose, and secure the nipple 22 by screwing a locking nut 23 against the outside surface of the cup piece 19A, and in case the hole is unthreaded a similar nut 24, see Figure 4, can be screwed onto the end ofthe nipple 22 against ,the opposite inside surface of the cup piece as well. On the outer end of this pipe nipple 22, I screw a cap 25 to close its open end. This protruding nipple 22 with its cap 25 forms an anchorage for their cup piece19A to rigidly secure. it in the concrete which will later be poured around it.

After each of the fiush embedded. cup

v pieces 7 in the concrete first poured has had attached to it its opposingmating cup piece 19A, with its anchoring nipple 22 and cap 25, the concrete can then be poured as soon as the side forms, for this ad]acent unit are erected and are connected to the concrete unitson either side already poured.

When this adjacent connecting concrete -m'ass is first poured and while still in its workable semi-liquid and plastic condition,

' it is in intimate contact with the contraction joint faces ofthe seasoned concrete on either enters into its final stages this temperature becomes less and less, and the drop in temperature produces a reduction in its mass and its physical dimensions, thus causing its outer confines to contract towards its center and those portions originally in contact with "5 the mating face portions of the completed structure first poured on either side recedes from those faces, leaving an aperture or crack 26 between them and inasmuch as the cup pieces last placed with their nipples 22 and caps 25 are firmly anchored by these nipples and caps in this new contracting concrete, they also recede back from the flanged faces 8 of the cup pieces 7 embedded in the concrete first poured, so that'this receding movement produces a gap between the faces of the mating cup pieces 7 and 19A, in the concrete unit CU1 first poured and those i the 'concrete unit CU2 last poured.

When this receding movement between the mating cup pieces occurs, it is resisted only by thel bent nails 21 over their mating flanged edges, and these nails B consequently n are straightened ,sufficiently by thezrelative movement of the mating edges, as shown in Figure 3 to accommodate this movement.

In Figure 1, I illustrate a complete uid grout conveying unit set up within a form A and at a short but predetermined distance from it and with its cup member 7 securedl to the inside face of the form A by the nails.

The cup member 7 is illustrated, adjustably mounted on the outer'end of the horizontal pipe member 6 or 6A. by means of the c heck nuts; consequently it can be forced tightly up against the inside surface of the form A bythevoutside check nut, and then the nails are driven into the form and then bent down over the eripheral edge of the flange 8.of the cup i), and then the double wire 11 is applied to still further draw the top portion of the upper riser pipentowards the form, and then after the vertical part of the piping and the cup have been completely and properly adjusted, this unit would appear as illustrated in Figure 2. Then the next step is to secure the 4cu member 19A to the face of the cup member and as above described, and then our this t second unit with concrete, which after hard-` 120 ening having yreceded from that previously poured, then presents the conditionas-showm in Figure 3, which isl now ready to receivei the'. grouting material between the 'two masses of concrete, which is accomplished by pumping the grout into the header pipe 1 and forcing it into and between the two oppositely opposed but now slightly separated cups 7 and 19A, through the opening 27 between which the grout is forced' throughout 130 and the two masses or units of concrete are now integrally united into one monolithic block of concrete. In the construction of high dams, the units of concrete are so lofty hardened and the uuits that are poured afterthat they have to be built up to'their final height by a number of successive pourings, one upon one another; consequently there are horizontal joints between the units as well as the vertical contraction cracks that occur between those units that have set and Wards against their sides, and in extending the riser pipes from their header pipes vertically upward vthrough a high unit, I preferablyplace the cup members 8 feet apart, as illustrated lin Figure 5, which enables form erection and the successive vertical pourings of the unit until its final height is achieved to be performed in an easy and simple manner, insuring that, by thus making the grouting system of vertical increments of equal length, it can be inserted within and fastened to the-forms as. fast as they are erected, and attached to the system in lace below, contained in theconcrete alr ady poured and seasoning. t

`When` the entire concrete structure has I been completed, I have provided direct communication from thef'commo'n header pipe 1, which I have placed in a parallel position to the bottom portion of each contraction crack 26, see Figures 3 and 6,. through the vertical risers 2 and 2A, and the horizontal v nipples 6 to the aperture 26 between each of the flanged edges of the opposing cup pieces 7- and 19A into the contraction joints or cracks 26, see Figure `3, separating the dfferent concrete masses CU1 and 2, comprising the completed units, and these communicating points are all predetermined, and exactly positioned, at intervals both vertically and horizontally, suiciently close as to insure that when the grouting material is introduced under pressure from'the exposed ends of the common headers at the bottommost portions of those contraction 'oint apertures, thats-asI this grouting me ium rises from' the lower portions towards the top portions of the structure, lit drivesoutthe air before its advance, through-the to vof the 'aperture and the'exposed open en sfof the riser pipes carried to the top of the structure for that purpose, illing every portion ofthe joint voids in its upward course and'finallyv appearing at the-top of the joints and beginning to overflow from the to s 'ofthe riser pipes, which are progressive y capped. ,off to prevent escape of the grout until the highest ones are reached,at which stage the pumping of groutr into the bottom concrete ture, an that which is poured later, as hereheader .pipe is discontinued, the header.

plugged, and that particular joint is then invention in the forms with reference to that i oured in the first units of the strucin described, that this can readily be done,

j and -in so doing will in no Way depart from the spirit, import and intent of my invention.

The same procedure of pumping grouting media of any suitable material under pressure into the bottom header pipes of each of the remaining joints in turn until cach system has been entirely iilled progressively from the bottom to the top is followed until all the joints are grouted. The work of grouting can be performed at any time after the concrete has hardened upon both sides of the joint or joints, but the best results are obtained when the concrete has a temperature below normal and has attained maximum contraction as in the winter.

- When Vusing cement grout, I preferably pump each space that forms the lcontraction crack v26, full of clear water before= starting to introduce the grout, as this meistens allsurfaces which the grout is required to bond, and insures that the grout will reach all portions of the voids in the crack with its proper free flowing consistency,v which it would not otherwise retain were it progressively coming in contact with dry concrete and losing its moisture content by absorption therein. A

While IV have throughout the foregoing descriptionreferred to the contraction crack apertures as bein in a vertical plane, my v invention Contemp ates a similar and equally efficient use on those which may be required on otherl than vertical planes as well, and I accordingly include these contraction crack a ertures which are often required and pro'- vlded in other than vertical planes, as being within the 'spirit and intention of this application. v l

In the operation of `my system and apparatus for closing the contraction cracks formed in concrete units while erecting them, the great value and the advantages of my arrangement and construction are:

That the filling or bonding-mixture is introduced into .the joint at predetermined separate pointsprogressively fronrthe botbonding could ,nototherwise occur, that tlTe conduit system supplying the predetermined. points of entry-into the joint is entirely removed from and'fseparate .from and independent of the 'oint aperture, thereby making certain the delivery ofv thebondin mixture to the -predetermined points o entry into the joint aperture, that the size and cubical content capacity of the elements comprising my invention are materially less than any other similar invention now in use', andthis consequent reduction in the amount of grouting medium required to fill my elements permits the grouting' tol be accomj plished in a shorter space of time as less grout is required, land this time saving is` of great importance, as it is essential that all the grout be in place before its settin and hardening cycle commences; that the eaders, and vertical rlsers can be and are made from standard products obtainable from.

stocks and purchasable anywhere in the open market, that their size and points of interconnection can be varied at .will to fit each.

' by o taining special connections from a. re-

mote and possibly sin le source of supply are eliminated; that t e ease and celerity with which the various units can be assembled and installed in the forms is increased; and that the total` expenditure of moneys required for attaining the desired result is greatl lessened; and that the results so attaine are superior and preferable tothat of any other arrangement now in use.

My invention provides an inexpensive system .and apparatus for .constructing and grouti concrete structures, as.all of the l materia s I employ can be obtained at supply houses, and all of the materials I use can be quickly erected-in position to receive the concrete, and while I have illustrated and described the preferred construction and arrangement of my system and .apparatus for construction and grouting concrete. structures I do not wish to be limited to the construction and arrangement shown, as changes may be made in it without departing from the spirit of my invention. l

Having described my invention what I claim as new and desire to secure by Letters Patent is: l

1. Apparatus for grouting the contraction joint between twoconcrete units, comprising a header and distributer pipes located in the space in which one unitis to be poured, means fixed to the ends of the respective distributer pipes and yieldingly secured e,to the forms defining the contraction joint face of the first unit to prevent concrete from entering the distributer pipes during pouring of the said unit, individual covers and means for yieldingly securing the same to the respective means on said distributer pipes after pouring of `the said unit and removal of the forms, and means associated with said covers for fixing the same in .the other concrete unit.

2. The invention as set forth in claim 1',

wherein the said means in the distributer pipes comprise cup-shaped elements having their outerv open ends contacting with the said forms.

3. Apparatus for grouting the contraction joint between two concrete units, comprising a header and a plurality of distributer pipes, fittings on the ends of said pipes and having flanges abutting against the forms defining the contractionV joint face of the unit in which said pipes are embedded, covers yieldingly secured against the said flanged fittings to close said pipes, and means anchoring said covers in the second unit.

4. In apparatus for grouting the contraction joint between two concrete units, the combination with means embedded in the first unit and defining a header in the base p ortion of said first unit, vertical channels rlslng from sald header, and a plurality of horizontal channels -branching from said vertlcal channels and terminating flush with the jointface of said first unit, of individual closures `for each of said branch channels, said closures being yieldingly secured to the first unit after stripping the forms therefrom, and means on said closures for securely anchoring .the same .in the second unit.

5'. In apparatus for grouting the contractionv joint between two concrete units, the combination with. a verticalpipe in the first unit and spaced from the joint face thereof,

a plurality of branch pipes exten-ding from said vertical pipev towards said joint face, and flanged means on said branch pipes prol ll5 viding a temporary closure :forsaid branch f plpes during pouring of the first unit, oi?

covers for'- cooperating with said flanged means after stripping of the forms from the first unit to close said branch pipes during pouring of the second unit, means for yieldmgly ai'xing said covers to the respective flanged means, and means for anchoring said covers 1n the second un1t.

`6. In apparatus for grouting a contraction 'oint between two concrete units, the l combination with a grout distributing pi e terminating adjacent the form defining t e joint face of the rst unit, a flanged fitting iao on said pipe and engaging the form to close the end of said pipe,` and nails partially driven into said form and having their outer portions bent toward said ianged means to second unit, the nail ends exposed by re.

moval of the form constituting means for yieldingly securing said cover to said flanged means.

7. In apparatus for grouting a contraction joint between two concrete units, the combination of a header Within and adjacent the bottom of the space in which one unit is to be poured, vertical risers communieating with said header, branch pipes extending from 'said risers, flanged means on said branch pipes and means yieldingly holding said f ianged means in contact with the surface against which said 'concrete unit is' poured. f

8. The invention as set forth in claim 5, wherein said iianged means comprise cupshaped elements having peripheral ianges.

9. The invention as set forth in claim 5, wherein said anged means and said covers each comprise identical cup-shaped elements having peripheral flanges.

10. In a concrete construction of the type described, the combination with forms defining' the contraction joint face of a massive concrete unit, of means for closing the endet the contraction joint, a header and vertical risersspaced from and positioned by said forms, branch pipes extending from said risers toward said forms, and outlet means on said branch pipes and having ianges contacting with said forms to close said branch pipes during pouring of thel unit, said flanged means being permanently secured to said branch pipes and yieldingly secured to said forms, whereby upon separation of said forms and the concrete unit, said branch pipes are opened into the contraction joint space.

11. The invention as set forth in claim 10, wherein each of said joint closing means comprlses a metal stripl having lateral wings embedded in the concrete units and an intermediate Vshaped fold located in the joint space.

In testimony whereof, I atix my signature.

JOI-IN L. SAVAGE.

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