US2948042A - Apparatus for making hollow reinforced concrete bodies - Google Patents

Description

Aug. 9, 1960 K. D. sYLvr-:sTER

APPARATUS FOR MAKING HOLLOW REINFORCED CONCRETE BODIES 4 Sheets-Sheet 1 Filed March 14, 1955 INVENToR. Hennef/7 D 55//1/e5er BY g/v/ ir/fam...

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N Q Q Aug. 9, 1960 K. D. sYLvEsTER APPARATUS FOR MAKING HOLLOW REINFORCED CONCRETE BODIES 4 Sheets-Sheet 2 INVENTOR.

Filed March 14, 1955 Hennef/7 Q .Sg/Veser Arrow/Ey:

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Aug. 9, 1960 K. D. sYLvEsTER APPARATUS FOR MAKING HOLLOW REINFORCED CONCRETE BODIES Filed March 14, 1955 4 Sheets-Sheet 3 Q new INVENTOR. /Venneh y/a/es/er llmIm-.H-IIMH m I m H. rH.-.| ./V/A ...n f. n.

Aug. 9, 1960 K. D. sYLvEsTER APPARATUS FOR MAKING HOLLOW REINF'ORCED CONCRETE BODIES 4 Sheets-Sheet 4 Filed March 14, 1955 INVENTOR.

K/e/me//z Q y/Vesfe/-- BY Z040 Llinited States l Patented Aug. 9, 1950 APPARATUS FOR MAKING HOLLOW REIN- FORCED CONCRETE BODIES FiledMar. 14, 1955, Ser. No. 494,036

Claims. (Cl. 25-30) This apparatus relates generally to apparatus and methods for casting elongated hollow concrete bodies. More particularly it pertains to apparatus and methods adapted for the manufacture of hollow bodies utilizing pre-stressing.

It is well understood that theV pre-stressing of concrete structure or bodies has certain advantages. It tends to prevent the development of cracks, and with bodies of considerable length it may serve to provide suicient strength for handling without breakage. As applied to the construction of concrete piles, thebodies have been cast with Aopenings extending longitudinally the same through which reinforcing members are strung, after which the reinforcing members are tensioned and then bonded to the body by lling the openings with cement grouting. One difculty with this procedure is that it is not well adapted to manufacture of piles of considerable length. Furthermore the diiliculties involved in steinging reinforcement through the openings, and-filling lche openings with grouting, increases with increase in the length of the pile. Making the pi'le in sections, and then attaching the sections together, is unsatisfactory in several respects, particularly because it is diicult to secure a joint having adequate strength, and because of the handling expense involved.

In place of the procedure described above, it is possible to pretension cables or steel wires and cast the concrete body about the same, whereby after the concrete has hardened, release of the cables applies the desired stressing to the concrete. This method has likewise been diicult if not impossible to apply to the making of relatively long concrete bodies, particularly where it is necessary to have ,a hollow construction.

In general it is an object of the present invention to provide apparatus for the manufacture of pre-stressed concrete bodies, and which in particular is applicable to hollow bodies of extended lengths.

Another object of the invention is to provide apparatus of the above character which makes possible the pretensioning of reinforced members, with direct bonding of the concrete to the reinforcement.

Another object of the invention is to provide lan app-aratus which does not have the limitations of previous casting procedures and which can be used for the rapid and economical manufacture of hollow bodies to virtually any length desired.

Additional objects and features of the invention will appear from the following description of which the preferred embodiment has been set forth in detail in oonjunction with the accompanying drawing.

Referring to the drawing:

Figure l is a side elevation view, partly in section,

illustrating apparatus in accordance with the present inf vention.

Figure 2 is a cross section view taken along the line 2-2 of Figure l.

Figure 3 is a cross section view taken along the line 3-3 of Figure 1.

'Figure 4 is a detail in side elevation and in section, illustrating the manner in which the core of Figure 1 is shifted for successive casting operation.

Figure 5 is a detail in section illustrating another embodiment of `the invention.

`Figure 6 is a side `elevational view in section illustrating another embodiment of the invention in which the core is collapsible.

'Figure 7 is -a cross-sectional detail taken along the line 7 7 of Figure 6.

. Figure 8 is a side elevational detail in section illustrating another embodiment of the invention in which fluid is introduced i-nto the space within the poured concrete.

Figure 9 is a side elevational detail in section similar to Figure 8 but showing another embodiment in which sand or like divided material is introduced into the space within the poured concrete.

Figure l0 .is a side elevational View similar to Figure l, but illustrating another embodiment of the invention.

Figure 1l is a cross-sectional detail taken along the lines 11-11 of Figure l0.

Figure l2 is a cross-sectional detail taken along the line l2-12 of Figure l0.v

The apparatus illustrated in Figure l consists of an elongated rigid bed 10, which can conveniently be made of reinforced concrete, and which rests upon the ground. The end portions 11 of the bed may be upright extern sions as illustrated. The upper surface 12 of the bed may be lined with sheet metal or as otherwise formed to provide `a suitable casting surface. In this instance it is assumed that the body to be cast is a cylinder, and there fore the surface 12 is semi-cylindrical. A supplemental form 13, which may be in two or more sections, is removably positioned upon the bed, and forms with the bed fa complete mold for casting the exterior of the body. At suitable intervals along the length of the bed, the forms y13 are provided with the removable doors 14, when removed permit the introduction of a concrete mix.

The upright extensions 1-1 at the ends of the bed provide means for carrying the anchoring members 16. These members may be steel plates of suitable strength` removably attached to the end extensions 111 as by means of bolts 17. The anchoring members have suitably disposed openings for receiving the metal reinforcing members 18. These members may, for example, be steel wire or cable of the type used in the making of prestressed concrete structures. Heads 19 are applied to the extremities of members 18 and each member is tensioned to a pre-determined degree by suitable hydraulic jacks or other means well known to those familiar Iwith pre-tensioning operations. After a member has been tensioned to the degree desired, the heads 19 are applied in such a manner as to retain the tension. Assuming the casting of a hollow cylinder, it is desirable that the members 18 be spaced circumferentially labout the central horizontal axis of the complete form. An end wall 21 is provided `at that end of the bed where the pouring of the concrete mix is to commence. In Figure l it is assumed that pouring is to commence at the left hand end. The end wall 21 is apertured to receive the members 18, and may be positioned while the members 13 are being attached to the plate 16.

Within the complete casting form there is a core 22 which in this instance is in the form of a pipe or conduit, having ya .slight taper as illustrated. Initially one end of this form abutts against the wall 21. The other end is carried by `the guide means 23, which in this instance is in the form of a ring apertured toV accommodate the 3 reinforcing members 13. The core is attached to a pullrod or c-able 24, which extends through the opening in one of the lbed extensions 11, and which may connect with suitable means for shifting the core after each pouring operation.

It will be noted from Figure 1. that the length of the core 22 is slightly greater than the distance between the doors 14. The overall length of the casting form may be many times the length of the core.

Use of the apparatus described above and the carrying out of my method is as follows:

The core 22 is first positioned at one end of the complete form, as for example, the left hand end as shown in Figure 1. In order to hold the left hand end of the core centrally' with respect to the outer form, it may be necessary to insert a temporary prop between the smaller end of the core and the bed. The first door 14 overlying the core is removed and la suitable concrete mix introduced. Vibration or like techniques can be applied for proper fiow of the mix. When the space about .the core has been completely filled, the apparatus is permitted to stand until the cement has hardened a suicient amount to be self supporting. When the concrete has hardened sufiiciently, the core is shifted by pulling upon the cable 24, until its small end projects into the previously poured concrete a short distance as shown in Figure 4'. The second door 14 is now removed and a second pour of concrete applied. Before making the second pour it is desirable to wash or jet off the exposed end face 26 of the previous pour, in order to insure a good bond. After the second pour, the apparatus is permitted to stand until the concrete is self-supporting, after which the core 22 is again shifted for la third pour. It -is evident that this procedure can be repeated until the entire length of the body has been poured. After the last pour the apparatus is permitted to stand until the concrete has attained suflicient hardness for an effective bond with the reinforcing members 1S. The forms 13 are now removed, the projecting ends of the reinforcing members 18 severed, and the cast body removed from the -bed as by rolling it sideways. After the body has been removed, the core 22 can be removed from the end of the body.

it will be evident that the apparatus and method described above possesses many advantages over prior methods for the manufacture of hollow concrete piles or other bodies of extended length. The method is relatively economical, particularly because the apparatus is not unduly complicated and expensive, `and because the labor involved is not excessive. Although the body is cast with successive pours, perfect bonds are provided between successive pours, thus avoiding difficulties previously experienced in joining sections of pre-stressed concrete piles. Furthermore the pre-stressing squeezes the junctions between pours, and in general makes the complete cast body into a homogeneous unit. The method has no limitations with respect to the length of the body which can be cast. Thus it is possible to make hollow bodies in length heretofore impossible with prevailing methods.

Immediately prior to each pour, it is possible to introduce additional standard reinforcement into the space about the core. However, generally it is unnecessary to use standard reinforcement as distinguished from prior methods Where it is customary to use screening or like reinforcement to supplement the tensioning members.

Although the method and apparatus has been described above as applicable to the manufacture of a cylindrical body, it will be evident that other shapes can be made as desired, as for example, polygonal, rectangular or square.

With the method as described with reference to Figure l, each casting operation completely fills the space about the core, to contract the spacing ring 23. If desired each pourcanstop short of completely filling the space about the Vfcore; as indicated for example in Figure'S. In this inst-'ance'insteadflof usingthe'spacing-ring 23 of Figure l,

the ring 27 is provided which has its periphery contacting the reinforcing members 18. The length of the core 22 can be made somewhat greater than in Figure l. As indicated in Figure 5, the previous pour has stopped short of completely filling the space about the core, thus leaving relatively uneven end face 28. in the final casting operation, the space is, of course, completely filled with the mix.

The .apparatusv is not limited to the use of a tapered core. Any core structure which can be shifted from one position to the next can be used. In Figures 6' and 7 I have shown a core of the collapsible type. In'this instance the core consists of a longitudinally split cylinder 29, which is connected by the links 30` with the central rod 31. As is well known by those familiar with the collapsible forms of this type, rod 31 can be shifted longitudinally to spring the cylinder 29, whereby edges 29a and 291; are brought into overlapping engagement, to reduce the effective diameter. After each casting operation, a suitable tool can be used for collapsing the'form, shifting it to its new position, and then extendingthe form for the next casting operation.

As shown in Figure 8 the core form 35 is cylindrical Aand isco-nstructed like a piston. Pipe 36 connects with a source of fluid under pressure, which may be air or other gas or preferably water or other suitable liquid. By controlled yintroduction of uid under pressure the core 35 can `be intermittently or continuously moved as the pour proceeds. Maintenance of iiuid pressure serves to hold the poured mix in place thus facilitating movementof the form before the preceding pour has hardened to the point of being self-supporting.

Figure 9 shows another embodiment in which sand or other divided solid material is introduced for the purpose of holding the poured walls of concrete in place. In this instance the core 38 can be cylindrical or substantially cylindrical, and the wall 39, corresponding to the wall 21 of Figure 4, is imperforate. The core 38 is attached to a bar or cable 41 by means of which the core can be moved longitudinally. A nozzle 42 connects with the hose 43 and serves to introduce sand or like material into the space 44. The wall 46 of the form 38, through which the nozzle 42 extends, is shown provided with screened openings 47 for escape of air. When utilizing the embodiment of Figure 9, the sand is conveyed pneu-l matically `through the hose 43 to fill the space 44. The

filling of space 44 can be intermittent following intermittent longitudinal movements of core 38 or if the core is moved continuously, then the filling can proceed continuous-ly and progressively. FillingV of this space with `sand or like material forms a medium for the absorption' annular guide means S3 is mounted upon the Vcore 51 and is adapted to engage the tensioned reinforced members 18. An annular member 54 is attached to the Aextremity of extension 52 and is provided with openings for slidably accommodating theV reinforcing members '18.V A pipe or cylindrical member S6 has its one `end secured` to annular member 54 and its other end serves to carry anjannular member 57, which is disposedl in the same lplane as guide means 53.

Spirally wound reinforcement 58 is shown positioned within the pipe 56, with the convolutions relatively close together. For that part of the pile that has been poured and which is illustrated in Figure l, the reinforcement 58 has its convoiutions spread apart and extending about the tensioned reinforcing members 18. Suitable means, such as the pull cable 59, permits the core 51 to be moved between successive pouring operations.

The upper part 61 of the exterior form shown in Figures -12 has an extended slot 62 to facilitate pouring operations.

Operation of the apparatus shown in Figures 10-12 is as follows: Preparatory to casting a pile, suicient spirally wound reinforcement is packed into the pipe 56 to suffice for the complete pile. After members 18 have been positoned and tensioned, a part of the spirally found reinforcement is distributed along the core 51 preparatory to a pouring operation. Thereafter the rst pour is carried out, and after the concrete has partially hardened, the core together with the extension 51, is moved for the next pouring operation. Here again, before the pour is commenced, a suicient amount of spirally wound reinforcement is withdrawn from the pipe 56 and is distributed along the tensioned reinforcement 18, in the same manner as explained above.

Although the apparatus shown in Figures l0l2 is particularly adapted for the placement of the spirally wound reinforcement, it will be evident that such reinforcement can likewise be used with the apparatus of Figure 5. Thus, before positioning the reinforcing members 18, the sprally wound reinforcement can be introduced into the form. Reinforcement 18 is threaded through the spiral reinforcement and tensioned in the matter previously described. Then the spiral reinforcement is properly distributed and attached to reinforcing members 18 by suitable means such as wire ties or tack welding.

I claim:

`1. In apparatus for forming hollow concrete bodies of extended length having longitudinal pre-stressed reinforcement therein, a rigid horizontal casting bed, means for anchoring tensioned reinforcing members to the ends of the bed with said members being spaced circumferentially about the horizontal axis of the bed, the upper suryface of the bed providing a lower portion of a casting form, additional casting form means being positioned upon the bed to form therewith a complete form for casting the exterior of the body, said lform means having openings therein at longitudinally spaced intervals for the introduction of a concrete mix, and Ia core aligned with the axis of the bed and disposed within the reinforcement, said core having a length substantially less than the length of the bed and a slightly tapered configuration so as to be readily movable lengthwise thereof to different positions for successive casting operations to form one finished body, said core being further provided with annular guide means adjacent its point of greatest diameter and kadapted to sliding movements relative to said reinforcement and exterior form.

2. In apparatus for forming hollow concrete bodies of extended length having a longitudinal pre-stressed reinforcement therein, a horizontal rigid structural bed, means for anchoring tensioned reinforcing members to the ends of the bed, with said members being disposed as desired in the finished product, the upper surface of the bed forming a lower portion of a casting form, additional casting form means removably positioned on the bed to form with the bed a complete form for shaping the exterior of the concrete body, said form means having openings therein for introducing a concrete mix, and rigid means forming a core within the form, said core being formed so as to be readily movable longitudinally of the bed positions for successive casting operations to :form one complete integral body bonded to the tensioned members, said core being further provided with annular guide means adjacent its point of greatest diameter and adapted to slid* ing movements relative to said reinforcement and e terior form.

3. Apparatus as in claim l together with means for introducing uid under pressure into the space formed by said core.

4. Apparatus as in claim 3 in which said means for introducing uid under pressure serves to move the core longitudinally from one position to the next.

5. In apparatus for forming hollow concrete bodies of extended length having longitudinal pre-stressed reinforcement therein, a rigid horizontal casting bed, means for anchoring tensioned reinforcing members to the ends of the bed with said members being spaced circumferentially about the horizontal axis of the bed, the upper surface of the bed providing a lower portion of a casting form, additional casting form means being positioned upon the bed to form therewith a complete form for casting the exterior of the body, said form means having openings therein at longitudinally spaced intervals for the introduction of a concrete mix, a core alined with the axis of the bed and disposed within the reinforcement so as to provide a space Within a cast body, said core having a length substantially less than the length of the bed and a slightly tapered configuration so as to be readily movable to different positions for successive casting operations to form one finished body, said core being further provided with annular guide means adjacent its point of greatest diameter and adapted to sliding movements relative to said reinforcement and exterior form, and means associated with said core for introducing divided solid material into said space.

References Cited in the le of this patent UNITED STATES PATENTS 517,808 Ransorne Apr. 3, 1894 1,123,832 Atterbury Ian. 5, 1915 1,309,978 Carr July l5, 1919 1,486,204 Trullinger `et al. Mar. l1, 1924 1,722,038 Dougherty July 23, 1929 1,920,716 Schafer Aug. 1, 1933 2,153,741 Cobi Apr, 11, 1939 2,172,703 Freyssinet Sept. l2, 1939 2,306,037 Colvin Dec. 22, 1942 2,394,227 Barber Feb. 5, 1946 2,511,761 Barber et al June 13, 1950 2,609,586 YParry Sept. 9, 1952 FOREIGN PATENTS 10,620 Australia N'ov. 29, 1927 691,323 Great Britain May 13, 1953

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