US3912217A

US3912217A - Means for constructing a floor or ceiling with joists

Info

Publication number: US3912217A
Application number: US346662A
Authority: US
Inventors: Lars Ako Wilhelm Norlander
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-01-24
Filing date: 1973-03-30
Publication date: 1975-10-14
Anticipated expiration: 1992-10-14

Abstract

Concrete slab structures with depending beams are formed by casting concrete in a falsework structure comprising a plurality of transversely spaced longitudinal form members of inverted Ushape having downwardly extending flanges, the flange of one form member being spaced from the flange of the adjacent form member to define the lateral sides of a depending beam of the slab. The flanges of the form members are resilient and relatively thin and are subject to deformation by the introduction of concrete between the flanges. A ridid brace or support member rests on props and is intended to engage the flanges of adjacent form members and form a closure at the bottom thereof while also reinforcing the flanges. The support member is of U-shape and may be an extruded aluminum member, and the support member has upstanding side walls which extend along a considerable part of the height of the flanges of the form members such that upon introduction of the concrete between the flanges of the form members they will be pressed into uniform, intimate contact with the flanges and prevent lateral deformation of the flanges over the entire height thereof whereby the flanges are constrained to remain substantially straight.

Description

United States Patent [191 Norlander [4 1 Oct. 14, 1975 [76] Inventor: Lars Ako Wilhelm Norlander,

Skogsliden 9, Stocksund, Sweden [22] Filed: Mar. 30, 1973 [21] Appl. No.: 346,662

, Related US. Application Data [63] Continuation-in-part of Ser. No. 793,414, Jan. 23,

1969, abandoned.

[30] Foreign Application Priority Data Jan. 24, 1968 Sweden 959/68 [52] US. Cl 249/31; 249/176 [51] Int. Cl. E046 11/40 [58] Field of Search 249/23, 25, 28, 31-32,

Primary ExaminerRobert D. Baldwin Assistant Examiner.lohn McQuade Attorney, Agent, or FirmWaters, Schwartz & Nissen ABS'I RACT Concrete slab structures with depending beams are formed by casting concrete in a falsework structure comprising a plurality of transversely spaced longitudinal form members of inverted U-shape having downwardly extending flanges, the flange of one form member being spaced from the flange of the adjacent form member to define the lateral sides of a depending beam of the slab. The flanges of the form members are resilient and relatively thin and are subject to deformation by the introduction of concrete between the flanges. A ridid brace or support member rests on props and is intended to engage the flanges of adjacent form members and form a closure at the bottom thereof while also reinforcing the flanges. The support member is of U-shape and may be an extruded aluminum member, and the support member has upstanding side walls which extend along a considerable part of the height of the flanges of the form members such that upon introduction of the concrete between the flanges of the form members they will be pressed into uniform, intimate contact with the flanges and prevent lateral deformation of the flanges over the entire height thereof whereby the flanges are constrained to remain substantially straight.

8 Claims, 4 Drawing Figures US. Patent Oct. 14, 1975' SheetlofZ 3,912,217

MEANS FOR CONSTRUCTING A FLOOR OR CEILING WITH JOISTS CROSS-RELATED APPLICATION This is a continuation-in-part of Application of my earlier Application, Ser. No. 793,414 filed Jan. 23, 1969, and now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to apparatus for casting monolithic concrete structures such as slabs with depending beams.

2. Prior Art In erecting falsework for monolithic concrete structures, in particular ceilings, it is conventional to use form members or shutters made of metal or a plastic material reinforced in a suitable manner, eg with glass fibers.

It is desirable that these forms be as light to handle as possible, particularly with regard to stacking and transport, and consequently attempts have been taken to make the walls of the form members asthin as possible.

It is known to support the lower edges of the flanges of the form members in soffits which remain integral with the cast slab. Such soffits offer a minimal bracing effect on the flanges and fail to maintain the flanges absolutely straight over their entire height.

SUMMARY OF THE INVENTION An object of the invention is to provide apparatus for the casting of a slab with depending beams by which the flanges of the form members are maintained straight and undeformed over their entire height during casting.

A further object of the invention is to achieve the above with form members of minimum thickness the flanges of which are highly flexible and-normally subject to bending deformation.

According to the invention, pairs of flanges of adjacent form members are placed in transverse spaced relationship with one long edge of said flanges in abutment with a support member carried by support props, the side walls of the support members extending upwardly to a considerable part of the height of the flanges of the form members so as to serve as a brace to resist deformation of the flanges over their entire height.

The height of the side walls of the support members is of the order of about 25 to 45% of the height of the flanges and is the minimum necessary to guarantee straightness of the flanges. If the height of the side walls is less, the flanges can bend inwardly in the region along the height of the sidewall or can bulge outwardly above the side walls. If the height exceeds the critical limit an unnecessary expenditure of material ismade and the cost and weight is increased unnecessarily.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a mould structure using form members and supporting members according to the invention,

FIG. 2 is a perspective view of a spliceconnection according to the invention, a

FIG. 3 is a plan view of the splice connection as shown in FIG. 2, and

FIG. 4 is a section through an end connection between a form member and a wall or the like.

DETAILED DESCRIPTION of transversely spaced longitudinal form members 1;

which are supported by supporting members 2 which in turn, in a manner known per se, are supported by beams 3 and props 4. As already pointed out, it is of greatest importance that the mould structure be as easy to build up as possible. At the same time the mould elements must be so designed as to prevent leakage of concrete as well as deformation of the mould walls. The form elements according to the invention are made from a material such as reinforced plastics having resilient properties.

As appears from FIG. 1 the form members have an inverted U-shape, the flanges 5a, 5b being relatively thin and having end portions 6a, 6b extending obliquely from the rest of the flanges which as seen slightly diverge from each other. The end portions are preferably bevelled to constitute tongue-like portions. As will appear later, the flanges 5a, 517 should be rather flexible but the web portion 7 of each form member should in contradistinction thereto be as rigid as possible. To obtain this, the web portion is provided'with a number of stiffening ribs 8. According to the invention these ribs are hollow thereby making it possible to combine the desired rigidity with low weight. To obtain such hollow stiffening ribs the following arrangement is usedi The form members are placed upside down such that their flanges 5a, 5b are directly upwardly. Profiled members, preferably semicircular tubes, made from cardboard or the like are then placed in the desireddirection and a plastic solution is poured in the tubes such that the profiled members will be joined with the form member. After hardening the ribs are integral with the form members.

As appears from FIG. 1, the ribs not only cover the underside of the web portion 7 but also continue into the upper portions of the flanges 5a, 5b. Thanks to this construction, the flanges will be effectively pivoted to the transition Zone between the flange in question and the web portion and this property of the form member is essential for the mould construction as will become apparent later.

The form elements described, which may also be provided with longitudinal stiffening members and the like, form together with web portions 9 of supporting members 2 now to be described the mould for casting a ceiling or similar structure which is to be produced. The flanges 5a, 5b of two adjacent form members thereby constitute the sides of the mould for the depending rib while the end portions 6a, 6b of said flanges together with the web portion 9 of the supporting member 2 constitute the underside of said rib or beam mould. The supporting members 2 are made from a metal, preferably aluminum and they are U-shaped in general with upstanding flanges 10a, 10b, which are slightly diverging. The flanges of the support members extend along a certain length of the form members for a reason to be explained later. In order to increase the rigidity of the supporting members, flanges 10a, 10b have outwardly directed portions 11a, "11b.

The casting operation is carried out as follows:

The supporting members are supported in parallel relationship on beams 3 and/or props 4 as shown in FIGS. 2 3. It is to be noted that the supporting members need not be fixed to their support but merely rested in position.

The form elements are then applied as shown in FIG. 1 such that the inner sides of their flanges are in contact with corresponding sides of the flanges 10a, 10b of the supporting members. The mould is now completed and concrete is poured thereinto. Owing to the resiliency of the flanges 5a, 5b of the form members, the flanges are pressed into uniform intimate contact with the flanges of the supporting members under the influence of the weight of the concrete. The lip-shaped ends 6a, 6b of the form member flanges enable a leakage-free connection and a smooth transition between the flanges 5a, 5b and the web portion 9. The height of the supporting member extends to approximately a zone of the form member flange in which the deformation would reach a maximum if unsupported and exposed to the influence of the concrete. The height of the flanges 10a, 10b of the supporting members is about 25 45% of the height of the form member flanges and is the minimum necessary to guarantee straightness of these flanges. If the height is less, the flanges 5a, 5b of the form members can bend inwardly in the region along the height of the supporting member flanges 10a, 10b or can bulge outwardly above this flange. If the height exceeds this value, an unnecessary expenditure of material is made and the cost and weight is increased unnecessarily. Thus it is seen that a concrete mould which is extremely simple and easy to use has been obtained.

Cast concrete ceilings must be left supported for considerable lengths of time until the curing process has ceased, and it is necessary, unless special measures are taken, to leave the form members in place for an equal length of time. This means that the constructor is forced to wait a considerable time until he can re-use the relatively expensive form members for other casting operations. It is necessary that the actual device used to prop the cast structure be retained in place for the entire period of time for the concrete to set, as defined in appropriate standards.

In order that the form members can be removed as quickly as possible the construction according to FIG. 2 and 3 may be employed. Therein, the supporting member comprises several pieces 12a, 12b each having approximately the section of supporting member 2 and each being cut along a respective transverse line 13a, 13b and an associated longitudinal line 14a, l4b such that each piece has a respective longitudinally projecting extension 15a, 15b. Consequently a rectangular opening is produced between two adjacent pieces 12a, 12b. A central plank l6 and two side planks 17a, 17b having a length exceeding that of the extension 15a, 151; are mounted as clearly shown in FIGS. 2 and 3. A plank 18 having a width approximately corresponding to the combined width of the

planks

16, 17a, 17b is secured to each piece 12a, 12b to form continuations of

planks

16, 17a, 17b thereby constituting an uninterrupted wooden bottom surface.

After the structure has been cast and is sufficiently self-supporting, the beams 3 can be removed and the prop 4 is used to support the central plank 16 as indicated above in FIG. 3. When removing the beams 3, the supporting members 12a, 12b may also be removed and as a consequence thereof the form members 1 may also be removed which means that said form members as well as the supporting members may be re-used at other locations for continued casting work. It may be noted that a plant (not shown) which has approximately the size of the opening between the supporting members 12a, 12b may be secured to the underside of the central plank 16 thereby facilitating the proper location of said central plane.

Usually the length of a ceiling is a multiple of the length of a single form element 1. In such cases several form elements are placed in end to end abutting relation. Thus it may be necessary to press said form elements towards each other. It is also necessary to arrange a transition between the ends of the outermost form elements and the walls of the structure. To this end, the outermost form elements are not open but closed by an end wall 19 which includes an integral horizontally extending flange 20 which terminates in a vertical downwardly extending flange 21 in which a bushing 22 is moulded. This bushing has a threaded hole for receiving threaded shank 23 of a screw 24 which is provided with a hole for a rod 25 by means of which the screw may be turned. The end of the screw acts against a flange 26 of an angularly bent member whose remaining flange 27 normally forms an angle of less than with flange 26. The angularly bent member is made of a resilient material such as sheet metal and is provided with guide elements, for example identations 28, for centering the end of screw 24 in relation to the flange 26.

When the supporting members are in place and the form elements have been placed into abutting relation with each other, the elements according to FIG. 4 are brought in the position shown in full lines. By turning the screw 24, the flange 26 is then pressed into contact with the side wall 29 and as a consequence thereof the flange 27 is pressed down to the position shown in dash dotted lines in FIG. 4. In this position an even transition between the ceiling and the side wall is obtained while at the same time, the form elements are pressed against one another. Of course both ends of each form member may be constructed as shown in FIG. 4 but it is often sufficient to provide such an arrangement at only one end. In such case, the opposite end isopen or closed but formed to sealingly contact the opposite side wall.

Numerous modifications and variations are also possible without departing from the scope of the invention as defined in the appended claims.

What is claimed is:

1. A mould construction for casting concrete slab structures with depending downwardly directed beams, said mould construction comprising a plurality of transversely spaced form members of inverted U-shape each having horizontal webs and downwardly extending flanges, said form members being arranged in such a relationship that one downwardly extending flange of one form member is spaced from the adjacent flange of an adjacent form member to form the lateral sides of a mould for a depending beam of the slab, said downwardly extending flanges being resilient such that they may pivot about an axis located in the transition zone between the flange and the web of the form member under the influence of the pressure of the concrete poured into the mould between two adjacent flanges, and brace means externally supported and of U-shaped rigid profile including web portions and vertical flanges, which web portions bridge the flanges of two adjacent form members such that the vertical flanges engage the inner surfaces of the flanges of adjacent form members so that introduction of concrete in the mould will cause said flanges of the form members to be sealingly pressed against the flanges of the brace means, the latter preventing lateral deformation of said flanges of the form members over the entire height thereof such that such flanges are constrained to remain substantially straight, said U.-shaped rigid profiles each including a number of profile pieces arranged end to end each being cut along a substantially transverse line located at a distance from the end of the respective said profile piece, said cut ending near the flange which is opposite the one in which the cut started and continuing in a longitudinal cut extending to the free end of said respective profile piece so as to obtain a longitudinally extending projection, the cut out portions of two adjacent profile pieces being of reverse shape and cooperatively defining a rectangular opening in the web portion of the rigid profile when said profile pieces are placed in a face to face relationship, planks covering said opening and having a total width corresponding to the width of the web portion of said profile pieces and a length exceeding the length of the rectangular opening, at least one prop arranged to support at least one of said planks such that said prop may support the casting when the remaining props or beams supporting the rigid profiles have been removed, thereby making it possible also to remove the form members and said rigid profiles for re-use.

2. A mould construction as claimed in claim 1 wherein the flanges of the U-shaped rigid profile have upper ends with outwardly facing flanges thereat.

3. A mould construction as claimed in claim 1 wherein the planks are constituted by a central plank and two side planks, at least one of said planks having secured to its underside a further plank fitted in the opening between said two adjacent profile pieces.

4. A mould construction as claimed in claim 1 wherein the form members include ribs stiffening its web portion and part of its flanges, the end portions of said flanges of the form members extending obliquely relative to the remaining part of said flanges to form downwardly diverging sealing lips.

5. A mould construction as claimed in claim 4 wherein the stiffening ribs of the form members extend transversely on the underside of the web portion of said inverted U-shaped form member and extend into the transition zone between the web portion and the flanges and terminate a short distance beyond said transition zone to obtain a relatively rigid web portion with flanges which are pivotable relative to said web portion.

6. A mould construction as claimed in claim 8 wherein said ribs comprise semicircular tubes, and a plastic material integrally bonding the tubes to the form members.

7. A mould construction as claimed in claim 4 wherein said brace means is made from aluminum.

8. A mould construction for casting concrete slab structures with depending downwardly directed beams, said mould construction comprising a plurality of transversely spaced form members of inverted U-shape each having horizontal webs and downwardly extending flanges, said form members being arranged in such a relationship that one downwardly extending flange of one form member is spaced from the adjacent flange of an adjacent form member to form the lateral sides of a mould for a depending beam of the slab, said downwardly extending flanges being resilient such that they may pivot about an axis located in the transition zone between the flange and the web of the form member under the influence of the pressure of the concrete poured into the mould between two adjacent flanges, and brace means externally supported and of U-shaped rigid profile including web portions and vertical flanges, which web portions bridge the flanges of two adjacent form members such that the vertical flanges engage the inner surfaces of the flanges of adjacent form members so that introduction of concrete in the mould will cause said flanges of the form members to be sealingly pressed against the flanges of the brace means, the latter preventing lateral deformation of said flanges of the form members over the entire height thereof such that such flanges are constrained to remain substantially straight,

said form members being constituted by a plurality of inverted U-shaped form members pieces placed in face to face confronting relation along open edges thereof, at least one of the end pieces being closed and having a substantially horizontally extending flange continuing into a substantially vertical downwardly directed flange, the latter flange having a threaded bushing, a screw threaded into said bushing and having a free end, an angularly bent member of a resilient material including an obliquely downwardly directed flange against which the free end of the screw bears and a second flange resting on the upper surface of said horizontally extending flange of the form member, the angle between said flanges of the bent member being initially less than said obliquely downwardly directed flange including means for guiding the free end of the screw such that said flanges will, upon action of the screw, be sealingly pressed one against a supporting vertical wall and the other against the upper side of said horizontally extending flange of the form member.

Claims

1. A mould construction for casting concrete slab structures with depending downwardly directed beams, said mould construction comprising a plurality of transversely spaced form members of inverted U-shape each having horizontal webs and downwardly extending flanges, said form members being arranged in such a relationship that one downwardly extending flange of one form member is spaced from the adjacent flange of an adjacent form member to form the lateral sides of a mould for a depending beam of the slab, said downwardly extending flanges being resilient such that they may pivot about an axis located in the transition zone between the flange and the web of the form member under the influence of the pressure of the concrete poured into the mould between two adjacent flanges, and brace means externally supported and of U-shaped rigid profile including web portions and vertical flanges, which web portions bridge the flanges of two adjacennt form members such that the vertical flanges engage the inner surfaces of the flanges of adjacent form members so that introduction of concrete in the mould will cause said flanges of the form members to be sealingly pressed against the flanges of the brace means, the latter preventing lateral deformation of said flanges of the form members over the entire height thereof such that such flanges are constrained to remain substantially straight, said U.-shapEd rigid profiles each including a number of profile pieces arranged end to end each being cut along a substantially transverse line located at a distance from the end of the respective said profile piece, said cut ending near the flange which is opposite the one in which the cut started and continuing in a longitudinal cut extending to the free end of said respective profile piece so as to obtain a longitudinally extending projection, the cut out portions of two adjacent profile pieces being of reverse shape and cooperatively defining a rectangular opening in the web portion of the rigid profile when said profile pieces are placed in a face to face relationship, planks covering said opening and having a total width corresponding to the width of the web portion of said profile pieces and a lenngth exceeding the length of the rectangular opening, at least one prop arranged to support at least one of said planks such that said prop may support the casting when the remaining props or beams supporting the rigid profiles have been removed, thereby making it possible also to remove the form members and said rigid profiles for re-use.

8. A mould construction for casting concrete slab structures with depending downwardly directed beams, said mould construction comprising a plurality of transversely spaced form members of inverted U-shape each having horizontal webs and downwardly extending flanges, said form members being arranged in such a relationship that one downwardly extending flange of one form member is spaced from the adjacent flange of an adjacent form member to form the lateral sides of a mould for a depending beam of the slab, said downwardly extending flanges being resilient such that they may pivot about an axis located in the transition zone between the flange and the web of the form member under the influence of the pressure of the concrete poured into the mould between two adjacent flanges, and brace means externally supported and of U-shaped rigid profile including web portions and vertical flanges, which web portions bridge the flanges of two adjacent form members such that the vertical flanges engage the inner surfaces of the flanges of adjacent form members so that introduction of concrete in the mould will cause said flanges of the form members to be sealingly pressed against the flanges of the brace means, the latter preventing lateral deformation of said flanges of the form members over the entire height thereof such that such flanges are constrained to remain substantially straight, said form members being constituted by a plUrality of inverted U-shaped form members pieces placed in face to face confronting relation along open edges thereof, at least one of the end pieces being closed and having a substantially horizontally extending flange continuing into a substantially vertical downwardly directed flange, the latter flange having a threaded bushing, a screw threaded into said bushing and having a free end, an angularly bent member of a resilient material including an obliquely downwardly directed flange against which the free end of the screw bears and a second flange resting on the upper surface of said horizontally extending flange of the form member, the angle between said flanges of the bent member being initially less than 90*, said obliquely downwardly directed flange including means for guiding the free end of the screw such that said flanges will, upon action of the screw, be sealingly pressed one against a supporting vertical wall and the other against the upper side of said horizontally extending flange of the form member.