CA1224343A - Cassette for casting of framework - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A framework cassette of thin sheet to be joined to adjacent cassettes so as to constitute a lost form when casting concrete framework and co-operating with the concrete in the finished framework as regards the absorption of forces is pro-vided which comprises a rectangular bottom along the two longitu-dinal sides of which edge beam sections are bent up. These edge beam sections comprise in part of an upper, horizontal flange, a vertical web with bulges and furthest down a sleeve. On the sleeves and between them is located a top section which is also secured thereto. The space between the top section and bottom of the cassette may be filled with insulation or used for installa-tion material. The concrete is cast over the top section and between the webs.

Description

The present invention relates to a cassette made of thin sheet or a similar material to cons-titute a lost form when casting concrete framework while cooperating with the concrete in the fini-shed framework in the absorption of forces.
It has been known how to cast framework with the aid of an integral form consisting of adjacent cassettes arranged the underside of the form constituting a complete ceiling in the space under the framework. Such a cassette consists of a U-shaped, longitudinal unit of thin steel sheet comprising a rectangular bottom with an edge beam section extending along its two respective parallel longitudinal sides, substantially at a right angle to the bottom on the side which is to be turned up. The edge beam section comprises both a web rising at a right angle from the bottom and at its upper edge a flange extending at a right angle from the web and towards the centre on one side of the cassette and from the centre on its other side. This imparts to the cross-section of the edge beam section a shape enabling adjacent cassettes to be hooked into one another so as to form a continuous framework.
The flanges are at their free edges provided with a support edge facing downward, which ensures additional stability and prevents two adjacent units from sliding apart during the casting process.
When casting a framework with these cassettes by means of a form, their ends are made to rest on the load bearing structure of the building, which may consist~e_s_-u~ a steel load bearing struc-ture, temporary support beams resting on temporary columns sup-porting it along its length. The casettes in the form are hooked to one another in sequence until the entire area of the framework has been covered. Once the adjacent webs have been joined, for instance with aid of rivets, the concrete is applied.
The webs of the edge beam section are provided with holes and aligned with one another in two adjacent edge beam secL:iolls, as a result of whi.ch tile concrete fo.rms a connecti.or alorl(J t~ e length of tlle bearrls.
'I'he cassett:es are subject to tensile forces acting in tl-lc-~.i.r p:lalle bot.ll duLir-~g castin~ and after hardening and loadin O r the concrete. It :is therefo:re i.mportarlt that the cassettes should be joined with great accuracy. 'I'hi.s has l)rovecl to be diffi.cult with previous structures. Apart from a reduce capacity to absorb such tensile stresses the cassettes had a tendency to separate owing to indentations about the rivet heads but also because the fasteners were located -too far from the undersides of the cassettes. Fur-thermore, if a fire broke out, the edge beam sections used also lo he in part directly exposed to heat, whi.ch i.s normally not permissible, unless special measures were taken.
Nor are these structures proof against -the escape of unbound concrete water while the concrete is being cast, such water bei.ng able to flow down on the undersides of the cassettes causlng such disfigurations -that costly measures could not be avoided.
The present invention provides a framewo.rk cassette without any of the disadvantages of the conventional cassettes, whlch is easier to install and to join and can also be made sound absorben-t instead of being a source for echos.
~ccording to the present invention thexe is provided a cassette for use as a los-t form when casting concrete -therein, sa:i.d cassette comprising a generally rectangular bottom panel which, when said casse-tte is positioned for use, ex-tends in a first generally horizontal plane, said generally rec-tangular bottom panel having opposite firs-t and second elongated side edges, and first and second side walls respectively connected along the length of the~firs-t and second side edges of said generally rectangular bottom panel, -thus defining inrler and 3~3 oute:r clirections oE sald cassette, said fi.rst side wall compris-iny a lirc;t flange which is conl~ected to said first side edge oE
said gerleral.l.y .rectangular hottom parlel and wh:i.ch exterlds up-wardly from saicl bottom panel in a first generally vertical plane; a second flange which is connected to said flrst flange and whlch ex.ends outwardly of sai.d casset-te ln a second gener-ally horlzontal plane; a thi.rd flange whlch is connected to said second flange and whlch extends upwardly ln a second generally vertlcal plane, said third flange including vertically spaced apar-t curved portions which extend inwardly of said cassette along the lengt}l of said third flange; and a fourth flange which is connected to sald thlrd flange and which extends outwardly of said casset-te in a -third generally horizontal plane, said second si.de wall comprising a fifth Elange which is connected to said second side edge of said rec-tangular bottom panel and which extends upwardly from said bottom panel in a third gener.ally vertlcal plane; a slxth flange whlch is connected to said fifth flange and which extends inwardly of said cassette i.n a fourth generally horizontal plane a seven-th flange which is connected to said sixth flange and which extends upwardly in a fourth generally ver-tical plane said seventh flange including verti-cally spaced apart elongaged curved portions which bulge along the length of said seven-th flange and inwardly of said cassette;
each of said elongated curved portions of said seventh flange being located above said generally rectangular bottom panel at a hei.ght equivalent to the helght above the generally rectangular bottom panel of the elongated curved portlons of sald third flange; and an elghth flange whlch extends lnwardly of said cassette i.n a fifth generally horizontal plane.
According to the present inven-tion therefore there is provided a framework ca~ssette which comprises a generally rec-tangular bottom wi-th an edge beam section extending along its 3 _ , .~

3~3 .resL)ective two parallel sides, the web thereof being sub.stan-I:ially r~erpendi.cular to the bot~.om and whereby the respective edge rc.inforcemerlt has a cross~section substantially identical with tl~at of a shelf at a slightly higher poi.nt on the web. The primary tensile reirlforcement consists of the cassette but an additional sectiorl can be provided capahle of consti.tuting a tensile reinforcement especi.ally in the transverse direction or constituting an economy device with a view to reducing the amount of concrete, creati.ng space for larger installations and having curves in the web projections, subse-luently referred to as bulges, so as -to bri.ng about a shear connection between the concrete and the sheet while acti.ng as a reinforcement for flat surfaces of the web.
Sui.tably said generally rectangular bottom panel in-cludes a plurality of upwardly-extending portions which extend along its elongated direction. Desi.rably the cassette includes a top section positioned above said generally rec-tangular bottom panel. Preferably said top section includes a middle portion, a first elongated side edge portion and a second elongated side : 20 edge portion, said first elongated side edge portion extending below said si.xth flange and being curved downwardly to contact said fif-th flange and said generally rectangular bot-tom panel.
More pxeferably said second elongated side edge portion of said top section includes a first section which extends above said second Elange in a sixth generally horizontal plane, and a second sec-ti.on which is connected to said first section and which extends in a fifth generally vertical plane. Sui-tably said first section of said top secton and said second flange of said wall include aligned holes therein and wherein said middle portion of said top section includes holes therein near said fi.rst elongated side ed~e portion, said holes enabling said casse-tte to be connected to adjacent cassettes by connecting - 3a -,.~ ......

mealls passincJ througll said holes. Desirably sai.d middle por-tiorl of sa:id top section is generally flat and extends in a seventh ~eneral~.y horizorltal plarle. Mbre desirably there is pro-vi.ded between said generally rectangular bottom panel and said top section, an~ wherein sound-absorbing material is located with sa:id cavity. Preferably a cavity is provided between said generally rectangular bottom panel and said top section, and where:irl fire-resitant material is located with said cavity.
Suitably said second elongated side edge portion of said top section includes a third section connected to said second section, said third sect:ion extending inwardly of said cassette at an oblique angle, said third section being capable of contac-ting the lowermost elongated curved por-tion on said -third flange.
Thus, according to the present invention there is pro-vided a framework cassette of thi.n sheet material to be assemb-led with adjacent cassettes so as to form a lost form when cas-ting a c~n-crete framewDrk and to cooperate with the concrete in the completed frame-work with respect to the absorption of forces, the casætte comprising a kot-tom with edge rein.forcements extending respectively along two parallel lonai-tudinal sides thereof with substantially uniform crDss-sections, webs of -the said edge reinforcemerlts being substantially perpendicular to -the bottom and provided par-tly with steps and partly with flanges at the top thereof, which at one side face away from the centre of -the cassette and on the other side towards the centre, the hori.zontal surfaces of the steps facing in the same direc-tion as the flanges and the webs being provided with rows of bulges above the steps facing towards the centre of cassette and adjacent cassettes being adapted to be joined by means of ver-ti.cal screw or rivet connectors through the horizontal sur-faces of the two overla~ping steps.
The present invention will be further illustrated by - 3b -.~

~2~ 3 way of the accompanying drawings, in which:-Fig. 1 is a perspective view oE cassettes in accor dal-lce with an embodiment oE the inverltion resting on a shelf;
Fig. 2 is a cross-section of the cassettes castiny concrete;
Fig. 3 is a cross-section of the cassettes casting concrete and wi-th an economy device inserted; and Fig. 4 is a section of edge beam sections before and ~0 - 3c -af-ter joining.
The edge beam section 2, comprises both a web 3, and a f:lange 5, at its upper edge as well as a shelf 6, at a base point of the web 3. Thus, the flange 5 and the shelf 6, ex-tend at right angles from the web 3, shelf 6 towards the centre 10, of one side of the cassette 1 and flange 5 away from the centre 10, on its other side. The cross-section of the edge beam section 2, thus makes it possible for adjacent cassettes 1, to be hooked to one another to a cohesive and tight concrete form. At least the flange 5, which faces away from the centre 10 of the cassette, is provided at its free edge with an edge reinforcement 7, facing towards the edge plane. A reinforcement of the joints between two adjacent casettes 1, is thus achieved. The said web 3, also comprises projections or bulges 8, facing towards the centre 10, of the cassette 1 and constituting the main link between the cassette 1 and the concrete cast in the cassette 1. The bulges 8, reinforce also the plane areas of the web 3, so as to reduce the danger of buckling.
The cassette may also be provided with a rectangular top section 9, to be placed between the shelves 6 and covering the space between the web 3 of the cassette. One side thereof is curved downward and partly backward and up. The height of the curved part 12, is prior to mounting somewhat larger than the distance between the underside of the shelf 6 and the upper side of bottom 11 of the cassette. Thus, in mounting the curved part 12, it has to be inserted under the shelf 6 and is resiliently pressed together to some extent so as to join tightly to the underside of the shelf 6, the edge beam section 2 and the bottom~11 of the cassette. The opposite side of the top section 9, is bent up at a right angle and should after mounting in the cassette 1, follow the side of 3~3 the web 3, upward to the lower row of bulyes 8, terminating ln an edge obli~uely bent lnward and upward, i.e. the '10 ~ a -~ ap edge 13, which advantageously snaps fast under the undersides of the bulges 8. The top section 9 can have a substantially flat top surface 17, which after assembly extends between both webs 3, o the cassette 1, or may have an upward bulging top surface 18.
When castin~ the concrete it is intended that the top section 9, close off the web 3 and the bottom 11 of cassette 1, to create a cavity below the top section 9. The bottom 11 of the cassette can for instance be perforated through the enclosure so as to achieve a sound-damping effect. The cavity between the bottom 11 of the cassette and the top section 9, is advantageously utilised for requisite sound insulating mats, electricity and heat and ~entilation lines. When the top section 9 has a flat surface 17 between the webs 3 of the cassette 1, the top section 9, also acts as a tensile reinforcement in the direction transverse to the longitudinal direction of the cassette 1. When the upper surface of the cassette 1 is bent upward at 18, the capacity of the top ; section 9 to absorb tensile forces is lost but space is gained for installations and a large amount of concrete is saved, pri-marily reducing its weight. The main function of the concrete is after all absorbing the pressure loads in the upper sections of the framework and in forming a surface.
When assembling framework cassettes 1, in order to cast a framework the said cassette 1, is hooked to the preceding one so that the edge reinforcement 7, of the upper flange 5, grips the free edge of the flange below 5, as a result of which the respec-tive positions of the cassettes 1, are fixed. Pipes, conduits and cables as well as sound-absorbent mats 14, are now placed on the bottom 11 of the cassette, whereupon the curved part 12, of the top section 9, is inserted into the recess below one shelf 6 and fixed to shelf 6, of the opposite web 3. The top sections 9 are secured on the one hand to the horizontal surfaces of the shelves 6 and on the other hand to the top sections 9, of adjacent ~2Z~ 3 cassettes by self-cutting and self-tapping screws or rivets 16, fitted vertically through the shelves 6 of the said web and two top sections g, on the upper or lower side of the shelf 6. When the top section 9 is exposed to tensile stresses at a right angle to the longitudinal directlon of the edge beam sections 2, the joint absorbs this stress as a shear stress acting on the fastener. This means inter alia that no indentations are formed about the heads in the sheet. As a resul-t of the arrangement where the webs 3 and the flanges 9, face the same direction, room is made for modern assembly tools required for the vertical joints. It is advantageous to locate the shelves 6, at as low a level as possible since, inter alia, projecting parts of the joint actively take part in the cooperating between -the concrete and the cassettes 1.
A disadvantage of having the shelf 6 and the flange 5, facing in the same direction is that the web 3 tends to be deflec-ted in that direction and subjected to loading. This can be avoided ~y inclining the web 2 of the cassettes 1, the shelf 6 - and flange 5, of which are located uppermost during assembly, towards -the centre 10 of the cassette, so that the web 3, forms an angle of 70-89 with the bottom 11, of the cassette, see left-hand illustration in Figure 4. When the ad;acent webs 3 are ~oined, see right-hand illustration in Figure 4, the assembly is inclined. In the loaded state the assembly tends to turn in the opposite direction. As a result the bending resistance of the cassette increases when it ls loaded during the casting process since the controlled bending axis coincides with the main axis of inertia of the edge beam sec-tion 2. As a result an otherwise accelerating stress char-acteristic is obviated when bending a cassette 1.When joining the webs 3, the bottom 11, of the cassettes are bent slightly upward thus compensating any downward bend when 3l~343 they are :Loaded with concrete or i~ top sections 9 are used for installati.ons. With a view -to reducing the danger of the bottom - 6a -, . .

il of the cassette buckling, the latter c~n be provided with grooves l9. If require~ the cassette can also be made sound-absorbent by providing its bottom with a dense pattern of holes, preferably also filling the space next to the bottom with an in-sulating material 14, such as mineral wool. The insulation can be so selected as to ensure fire protection of the cast framework.
Having completed the assembly of the cassettes l, a layer of concrete is poured over the cassettes 1. After hardening of the concrete a construction results, which is characterised by high carrying capacity. As a result of this structure, which causes the joints between the cassettes to be tightly sealed, adjacent webs 3, are presse~ against one another when they are loaded by the flowing concrete, whereas with previous conventional structures where holes were provided to join the webs there was a tendency for the webs to be pressed apart owing to internal excess pressure on the part of the concrete water.
The cassette 1, forms a tensile reinforcement in the structure as regards bending perpendicularly to the longitudinal direction of the cassette 1. The top section 9, constitutes a tensile reinforcement as regards bending parallel to the longitu-dinal direction of the cassette l and this tensile reinforcement is largely retained even in case of a fire. The bulges 8, engaging one another and acting as dowels provide a very good shear connec-tion between the cassette 1 and the concrete. With this structure there is practically no danger of shear failure in the shear joint.
With correct assembly the casting form will be completely tight.
There are no holes in the web causing the concrete water to run out in the joints between the reinforcements, and the load exerted by the concrete compresses adjacent reinforcements, not as used to be the case with previous structures tending to separate them.

Claims (10)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A cassette for use as a lost form when casting concrete therein, said cassette comprising a generally rec-tangular bottom panel which, when said cassette is positioned for use, extends in a first generally horizontal plane, said generally rectangular bottom panel having opposite first and second elongated side edges, and first and second side walls respectively connected along the length of the first and second side edges of said generally rectangular bottom panel, thus defining inner and outer directions of said cassette, said first side wall comprising a first flange which is connected to said first side edge of said generally rectangular bottom panel and which extends upwardly from said bottom panel in a first generally vertical plane; a second flange which is connected to said first flange and which extends outwardly of said cassette in a second generally horizontal plane; a third flange which is connected to said second flange and which extends upwardly in a second generally vertical plane, said third flange including vertically spaced apart curved portions which extend inwardly of said cassette along the length of said third flange; and a fourth flange which is connected to said third flange and which extends outwardly of said cassette in a third generally horizon-tal plane, said second side wall comprising a fifth flange which is connected to said second side edge of said rectangular bottom panel and which extends upwardly from said bottom panel in a third generally vertical plane; a sixth flange which is connec-ted to said fifth flange and which extends inwardly of said cassette in a fourth generally horizontal plane; a seventh flange which is connected to said sixth flange and which extends upwardly in a fourth generally vertical plane, said seventh flange including vertically spaced apart elongated curved portions which bulge along the length of said seventh flange and inwardly of said cassette; each of said elongated curved portions of said seventh flange being located above said generally rectangular bottom panel at a height equivalent to the height above the generally rectangular bottom panel of the elon-gated curved portions of said third flange; and an eighth flange which extends inwardly of said cassette in a fifth generally horizontal plane.

2. The cassette as defined in claim 1, wherein said generally rectangular bottom panel includes a plurality of upwardly-extending portions which extend along its elongated direction.

3. The cassette as defined in claim 1, including a top section positioned above said generally rectangular bottom panel.

4. The cassette as defined in claim 3, wherein said top section includes a middle portion, a first elongated side edge portion and a second elongated side edge portion, said first elongated side edge portion extending below said sixth flange and being curved downwardly to contact said fifth flange and said generally rectangular bottom panel.

5. The cassette as defined in claim 4, wherein said second elongated side edge portion of said top section includes a first section which extends above said second flange in a sixth generally horizontal plane, and a second section which is connected to said first section and which extends in a fifth generally vertical plane.

6. The cassette as defined in claim 5, wherein said first section of said top section and said second flange of said wall include aligned holes therein and wherein said middle por-tion of said top section includes holes therein near said first elongated side edge portion, said holes enabling said cassette to be connected to adjacent cassettes by connecting means pas-sing through said holes.

7. The cassette as defined in claim 6, wherein said middle portion of said top section is generally flat and extends in a seventh generally horizontal plane.

8. The cassette as defined in claim 7, wherein a cavity is provided between said generally rectangular bottom panel and said top section, and wherein sound-absorbing material is located with said cavity.

9. The cassette as defined in claim 8, wherein a cavity is provided between said generally rectangular bottom panel and said top section, and wherein fire-resistant material is located with said cavity.

10. The casssette as defined in claim 5, wherein said second elongated side edge portion of said top section includes a third section connected to said second section, said third section extending inwardly of said cassette at an oblique angle, said third section being capable of contacting the lowermost elongated curved portion on said third flange.