US3059738A

US3059738A - Temporary concrete supporting system and method

Info

Publication number: US3059738A
Application number: US848491A
Authority: US
Inventors: Lutz Robert
Original assignee: LE MATERIEL SPECIAL D ENTPR SO
Current assignee: LE MATERIEL SPECIAL D ENTPR SO; SOCIETY LE MATERIEL SPECIAL D'ENTREPRISE
Priority date: 1958-10-13
Filing date: 1959-10-12
Publication date: 1962-10-23
Anticipated expiration: 1979-10-23

Description

Oct. 23,1962 LUTZ 3,059,738

TEMPORARY CONCRETE SUPPORTING SYSTEM AND METHOD Filed Oct. 12, 1959 2 Sheets-:Sheet 1 Oct. 23, 1962 R. LUTZ 3,059,738

TEMPORARY CONCRETE SUPPORTING SYSTEM AND METHOD Filed Oct. 12, 1959 2 Sheets-Sheet 2 Fig. 4 Y J;

United States Patent 3,059,738 TEMPORARY CONC ETE SUPPORTING SYSTEM AND METHOD Robert Lutz, Neuilly-sur-Seine, France, assignor to Socrety le Materiel Special dEntreprise, Paris, France, a

French society Filed Oct. 12, 1959, Ser. No. 848,491 Claims priority, application France Oct. 13, 1958 Claims. (Cl. 189-37) This invention relates to the temporary supporting systems or structures used in building generally horizontal expanses of concrete, such as flooring, to prevent collapse of the concrete during its setting period.

The structures used for this purpose generally comprise horizontal girders arranged in parallel spaced relation across end supports so as to underlie the concrete shuttering while the mix is setting. Such girders are usually made up from a plurality of aligned elements secured end to end to one another; alternatively exp-ansible girders are sometimes used which comprise telescopically slidable parts.

Where the expanse of concrete to be provided does not exceed a limited length, say 20 feet or so as in dwelling houses, such supporting girder may be used without requiring intermediate supports. However, for larger expanses of concrete above about 20 or 30 feet, intermediate supports have to be provided for propping the girders every 15 or 20 feet.

In either case a serious difficulty encountered with present-day concrete supporting structures of this kind is that, except in extreme cases where the expanse of concrete floor to be constructed is quite short, the supporting girders have to be retained in place for comparatively long periods of time that is, until the concrete has set sufficiently to be self-supporting over the full extent of the floor. This may take several weeks during which time the relatively costly supporting equipment is tied up and cannot be used elsewhere.

It is therefore a primary object of this invention to provide a concrete supporting system of the general character specified, which shall be so designed that a major part of it can be removed after a considerably shorter time than was heretofore possible, thereby increasing the rate of rotation of the equipment as between several worksites with considerable attendant economic advantage.

Another object is to provide a concrete supporting structure that will be very convenient and handy to erect and dismantle.

A further object is to provide a concrete supporting structure adapted simultaneously to serve as a portion of a bottom Wall for a concrete mould, which simplifies concrete pouring operations.

According to one aspect of the invention there is provided a system for temporarily supporting a generally horizontal expanse of concrete during setting, which sys tem comprises a number of girder-like elements of pre determined length alignable into at least one horizontal array and having top surfaces for supportingly underlying said concrete; also, intermediate supports for said array having top surfaces for supportingly underlying said concrete and having means, such as side recesses, for removably engaging therewith adjacent ends of an adjacent pair of girder elements of the array in aligned relation at opposite sides of each said intermediate support, and end supports for the array.

Preferably each end support includes means for adjusting the length of an outermost girder element of the array inserted therein so as to adjust the over-all length of the array according to requirements.

3,059,738 Patented Oct. 23, 1962 According to another aspect, the invention provides the method of building a generally horizontal concrete structure, such as a floor, including the steps of: erecting a temporary supporting structure comprising at least one array of aligned horizontal girder elements of limited length, intermediate supports for said array engageable with adjacent ends of an adjacent pair of girders, and end supports for the array, said girder elements and at least said intermediate supports having substantially coplanar upper concrete-supporting surfaces; providing concrete moulding means atop said supporting structure; pouring a concrete mix into the moulding means; allowing the mix to set to a degree such as to be self-supporting over a span corresponding to the length of a girder; removing said girders; allowing the mix to set further to a degree such as to be self-supporting over a span corresponding to the full length of the array, and then removing said intermediate supports.

The above and further objects, features and advantages of the invention will appear from the ensuing description made with reference to the accompanying drawings in which a form of embodiment of the invention is illustrated for purposes of illustration but not of limitation. In the drawings:

FIG. l is a general view in elevation of the supporting system of the invention in supporting condition,

FIG. 2 is a larger-scale view in perspective view of an intermediate support assembly used in the system,

FIG. 3 is similar to FIG. 1, but shows the system on disassembly,

'FIG. 4 is a large-scale showing a detal of an end support assembly,

FIG. 5 is a section on line VV of FIG. 4,

FIG. 6 is similar to FIG. 4 but shows the disassembled condition,

FIG. 7 is a plan view from below illustrating the attachment of a plank to a girder,

FIG. 8 is a section on line VIII-VIII of FIG. 7.

As shown in the drawings a supporting system according to the invention comprises as the basic components thereof a number of girders 1, intermediate supports 2 for interconnecting the ends of adjacent girders, standards or props 3 on which the supports 2 are supported, and end supports 4 in which the outer ends of the girders 1 are adjustably supported so as to permit of imparting to the aligned array of girders the precise over-all length required by the span of concrete to be supported.

The girders 1 may be lattice girders as shown, but it will be understood that any other suitable construction may be used therefor, such as solid web beams, or box girders, or the like. In any case the girders are preferably provided with a solid flat web or flange at the upper surface thereof which, in addition to its primary concrete-supporting function, may serve as a bottom mould Wall in which the concrete mix may be directly poured. In the illustrated embodiment this solid upper wall of the girder comprises a web 5 having a 0 section (as shown in FIG. 8), ie a section in the form of an incomplete box open in the downward direction. Secured to the side flanges of this member 5 are the side lattice members of the girder.

The intermediate supports 2 which serve to interconnect adjacent ends of adjacent girders 1 and transmit their loads through the props 3 to the ground may be constructed in various forms. As here shown each support 2 comprises a Q or hat section member 6 providing an upper wall for the member, and a pair of parallel spaced side plates 7, here shown of trapezoidal form, having their upper ends secured to midpoints of the side flanges of the member 6 in mutually opposed relation, and their lower ends resting on and attached to the top of a base member S which is generally similar in shape to that of the upper member 6 but smaller than it and extends in a direction normal to it for reasons presently described. The junction assembly 2 further includes the two pairs of stiffener tie members which connect the base of the side plates 7 with each outer end of the top member 6.

The intermediate supports 2 may be mounted on the tops of the props 3 in any suitable manner, not here described in detail. Preferably however, they are mounted by way of cross bracing members 9 inserted into the recesses of the members 8 and extending transversely of the supporting system so as to interbrace the adjacent parallel arrays of girders with one another.

In the side plates 7 of the intermediate support are formed the pairs of apertures 11, preferably square in shape, which serve for the insertion of key or pin members (designated 12 in FIG. 1). It is on the pin members 12 that the ends of the girders 1 rest in the assembled condition of the system shown in FIG. 1. By forcing the pins 12 into their holes the ends of the girders are forced into firm engagement with the member 6 thereby providing a rigid assembly. To dismantle this assembly, the pins 12 are withdrawn so that the related ends of the girders are released and are then allowed to drop down to the ground as shown in FIG. 3, whereupon they can easily be withdrawn completely as will presently appear. It should be understood that the intermediate support assemblies 2 may be constructed in a variety of forms other than that here shown.

As to the end support assemblies 4 these may be substantially similar in construction to the intermediate support assemblies 2. Thus an end support as here shown also comprises an O. or hat section member 13 similar to member 6, side plates 14 generally similar to the side plates 7 and formed with pinning openings for the pins 15 similar to the pins 12. Stitfener tics 16 corresponding to ties 10 are also provided. It will be understood that the outer end of a girder 1 can be inserted to a desired degree into an end support 4 and then blocked in its adjusted position by forcing the pins 15 into the holes therefor whereby the desired over-all length or span can be imparted to the system as explained.

It will be understood that an end support member 4 at its side remote from that into which the girder 1 is inserted takes support against some fulcrum surface such as an end supporting post or column of the concrete structure, shown at 18, or in fact any other suitable fulcrum. For this purpose the end assembly 4 comprises an outer bracket arm 17 adapted to rest on the top of the fulcrum 18 as shown in FIG. 4. However to facilitate removal of the girder 1, the bracket arm 17 is provided movable, being pivoted on a transverse pivot 19 in the assembly 4. The arm 17 may be a suitable flanged plate generally similar in cross section to the member 5 and smaller than 13 so as to fit within it pivotally. The arm 17 can be blocked in extended, horizontal, condition by means of a pin 20 inserted into a recess 21 in each of two side lugs 22 depending from the member 13.

In the assembled condition of FIG. 1 the arms 17 are blocked in their outwardly projecting, horizontal positions by means of the pins 20. On dismantling, the pins -20 are withdrawn whereupon the arm 17 can be swung assemblies 4 all are provided with fiat solid surfaces; a

continuous flat surface is available to serve as a bottom mould wall for the casting of concrete, thereby greatly facilitating the concrete pouring operations. In some cases however, the width of the flat surface thus provided may not be sufiicient in view of the width of the concrete beam, and in such cases it is contemplated in the invention that the transverse width of the fiat upper surfaces of the components supporting system can be augmented by placing suitable planking, or the like, across said surface as shown in FIGS. 7 and 8. As there shown a plank 23 is removably secured across the top of the upper flanged plate 5 of a girder by way of a flat plate 24 removably secured across the upper surface of plate 5 and a pair of brackets or gusset plates 25 are attached to the under side of the plate 24. At least one of the brackets 25 is formed with a slot into which a wedge-shaped key member 26 is adapted to be forced, the member 26 engaging the outer side of a flange of the member 5. Thus by forcing the wedge member 26 both gussets 25 are firmly clamped against the outer side flanges of the member 5, and a rigid assembly is provided.

In use, the supporting system is first assembled to the condition shown in FIG. 1, the assembly procedure being clearly apparent from the explanations given earlier herein. It will be understood that there may be more than one array of supporting girders similar to that shown in FIG. 1, extending in parallel spaced relationship under the expanse in which a concrete flooring is to be provided, the number of such arrays used depending of course on the transverse dimension of said expanse, just as the number of girders 1 used in each array would depend on the longitudinal dimension of the expanse to be floored. Conventional shuttering may then be laid over the supporting system and concrete poured therein in the usual way. While this concrete is still fluid its entire span is supported by the array of girders 1. However, after a relatively short time, such as for example three days for a typical concrete mix, the mix has become sufficiently selfsupporting to permit the girders 1 being removed, as earlier explained with reference especially to FIG. 3, while the standards 3 and intermediate support assemblies 2 are retained in place. The partially set concrete is now exclusively supported by the intermediate supports 2, allowing the girders 1 to be removed and reused at some other building site. After a further period of time when the mix has further solidified the members 2 and standards 3 are in turn removed. Because of the relatively short free span of concrete as represented by the average length of the girder elements 1 of the invention, and the relatively long extent of the supporting surfaces provided by the upper surfaces of the intermediate supports 2, it will be understood that the initial period at the end of which the girders 1 of the invention can be safely removed without any danger of the incompletely set concrete collapsing or sagging, is very much shorter than the period at the end of which it would be possible safely to remove supporting girders extending across the full span to be covered, as is the case with comparable concrete supporting structures currently in use. Thus, the time during which the main components of the system, i.e. the girders 1, are tied up is greatly shortener, since the rate of rotation of these components is correspondingly increased, with great economical advantage.

It is found that a satisfactory ratio between the average length of the girders 1 and the length of the intermediate supporting members 2 is about 3/1, the girders 1 may conveniently be provided with a length of about 10 feet and the members 2 about 3 feet.

It will be understood that a number of modifications may be made in the single embodiment of the invention illustrated and described without departing from the scope of the invention. Such modifications may involve the manner of construction of each of the main components of the system, girders, intermediate members and end members.

What I claim is:

1. A shuttering support for concrete flooring comprising at least two girders of like length, at least one connecting member, a prop supporting said connecting member, said girders being disposed in alignment on each side of said connecting member, said connecting member including elements adapted for retraction in a horizontal direction perpendicular to the longitudinal axis of the support, said girders including adjacent ends removably engaging said elements, and end extension pieces provided with openings in which the other ends of the girders are adjustably engaged thereby permitting adjusting the length of the support.

2. A shuttering support according to claim 1, comprising at least two connecting members and wherein each connecting member has a plane upper surface substantially aligned with the upper surface of the girders, the length of the upper surface of the connecting members, in the direction of the axis of the support, being substantially one-third the distance which separates adjacent connecting members.

3. A shuttering support according to claim 2, wherein the connecting members are provided with recesses, the support comprising transverse bracing elements in said recesses.

4. A shuttering support according to claim 1, wherein the end extension pieces comprise vertically retractable elements adapted for resting against lateral props.

5. A shuttering support according to claim 4, wherein said retractable elements of each end extension piece each includes a catch pivotal about a horizontal axis perpendicular to the longitudinal direction of the support and said catch is adapted for resting against lateral props, and an element sliding in the associated end extension piece parallel to said axis of rotation of the catch for engaging said catch.

References Cited in the file of this patent UNITED STATES PATENTS 1,212,654 McKay Jan. 16, 1917 1,270,043 Murphy June 18, 1918 1,999,783 Riesbol Apr. 30, 1935 2,094,849 Schneider Oct. 5, 1937 2,257,196 Schneider Sept. 30, 1941 2,557,693 Sachleben et a1. June 19, 1951 2,804,673 Fex Sept. 3, 957

FOREIGN PATENTS 479,029 Great Britain Jan. 25, 1938 147,007 Australia June 24, 1952 157,744 Australia July 21, 1954 1,020,986 France Nov. 26, 1952