AU773839B2 - False splay sideform system - Google Patents

Description

I k WO 01/44600 PCT/AU00/01549 1 FALSE SPLAY SIDEFORM SYSTEM This invention relates to building construction forrnwork, and more particularly to formwork used for casting concrete panels wherein panels are cast in a stack one on top of the other.

In stack casting of panels, a situation often arises where two panels of the same dimension are cast directly over one another, with the lower panel having a splayed edge. As a result, the upper panel overhangs the splayed portion of the lower panel. When a panel is cast with a splayed edge, it reduces the available casting area for the panel to be cast on top. In traditional formwork methods, a false casting bed is constructed usually from plywood to accommodate casting of the larger panel on top. However, this leaves imprints on the cast face of the top panel that require rectification work to be carried out following panel erection. The process of installing the false formwork and patching of the panel surface is both time consuming and costly.

It is an object of the present invention to provide an improved false splay sideform system which enables a panel to be cast on top of a lower splayed panel in an extremely simple and cost effective manner and without any formwork imprints being left on the cast face of the upper panel.

Broadly according to this invention therefore, there is provided a false splay sideform of hollow cross-section which includes a generally vertical outer side wall, an inner side wall extending at an inclined angle with respect to the outer side wall and which, forms the splay angle of the sideform and an upper wall extending between and interconnecting said inner and outer side walls, characterised by an upwardly extending flange which forms a continuous extension of the inner side wall, said upwardly extending flange and said upper wall forming a recessed area on top of the sideform for receiving a skim coat concrete layer during casting of the WO 01/44600 PCT/AUOO/01549 2 splayed panel, the upper terminal edge of said flange being located below the level of the upper edge of the sideform.

Desirably the upwardly extending flange is integrally formed with the sideform and is formed by a continuous coplanar extension of the inner side wall.

In another embodiment of the invention, the flange forms part of a separate false splay strip bent at the same splay angle as the sideform, said strip being removably attached to the upper wall of the sideform. Preferably the false splay strip is designed to extend the sideform splay edge profile to approximately 2mm below the top of the surface of the panel being cast.

Preferably the false splay sideform accommodates an approximately concrete skim coat to be poured over it thus extending the finished surface of the concrete to the overall width of the panel and thereby compensating for the surface area lost due to the splayed edge. Since the upper edge of the flange locates a small distance below the concrete surface, it does not imprint on the cast face of the panel cast on top. When the sideforms are removed, the skim coat of concrete falls away or can be easily broken from the panel and the splay sideform due to the break line created by the false form member.

In order to more fully explain the present invention, several preferred embodiments thereof are described hereunder in more detail with reference to and as illustrated in the accompanying drawings wherein: Figure 1 is an exploded end elevational view of a splay sideform and a detachable false splay strip, according to a first embodiment of the invention; Figure 2 is a sectional view of a tilt-up or pre-cast panel construction application showing two panels cast one on top of the other, with the lower panel being splayed using the splay sideform shown in Figure 1; WO 01/44600 PCT/AUOO/01549 3 Figure 3 is a perspective view of a false splay sideform made in accordance with a second embodiment of the invention; while Figure 4 is an end elevational view of the sideform shown in Figure 3.

Referring to Figures 1 and 2 of the drawings, there is shown an extruded false splay sideform 10 which comprises an upper wall 11, a bottom wall 12, an outer side wall 13 and an opposite inner side wall 14 which is inclined to the top and bottom walls 11, 12 so as to form a splay angle which, in this embodiment, is 45°. It will be appreciated that sideforms having splay angles of different sizes can be used. An intermediate horizontal stiffening web 15 interconnects the opposite side walls 13, 14.

Adjacent the inner upper edge of the top wall 11 and co-extensive therewith, there is provided a slot-forming flange 17 which defines a laterally inwardly opening slot for receiving an edge portion of a false splay strip or rail 18 which is v-shaped and bent at the same splay angle as the sideform side wall 14. In this embodiment the false splay strip 18 is formed of 1mm sheet metal and comprises a horizontal flange 19 and an upwardly inclined flange 20, with the free edge portion of the flange 19 frictionally locating within the slot formed by the flange 17.

As shown in Figure 2, the false splay strip 18 continues the sideform splay edge profile to just below the top of the cast panel surface 21 of the splayed panel 22.

As can also be seen from Figure 2, the stepped profile of the top wall 11 together with the false splay strip 18 define a recessed portion having a depth which, in this embodiment, is approximately 20mm and accommodates pouring of a concrete skim coat on top of the sideform 10. This enables a panel 24 above to be cast over the false skim coat 25 without any formwork imprints or imperfections.

1.

WO 01/44600 PCT/AUOO/01 549 4 It will be appreciated therefore that the false splay sideform effectively extends the finished surface of the concrete to the overall width of the panel 22 compensating for the surface area lost due to the splayed edge of the panel 22.

The skim coat concrete 25 on top of the sideform 10 is finished homogenously with the main body of the panel 22 and thus has a surface finish which is the same as that of the main body of the panel 22 so that there will be no imprints or variants to the finish of the mating cast face of the panel 24 cast on top. When the sideform 10 is removed, the skim coat 25 falls away or can be easily broken-off from the panel 22 due to the narrow break line created between the upper edge of the false splay strip 18 and the upper surface of the panel 22. This generally will be approximately 2mm thick. Thus, the internal edge of the splayed panel 22 only requires a light stone to smooth-off the 2mm break in the concrete surface.

Referring to the embodiment shown in Figure 3 of the drawings, there is shown an approximately triangular shaped sideform 30 having a vertical outer side wall 31, an upwardly inclined inner side wall 32 and an upper horizontal wall 33 extending between the side walls 31, 32. Again the sideform 30 is an extruded hollow aluminium member. In this embodiment the inner side wall 32 projects beyond the upper wall 32 so as to form a false splay flange 34 integrally formed therewith, with the upper edge of the flange 34 terminating at a level which is just below the upper flanged edge 36 of the outer side wall 31. The upper portion 37 of the side wall 31, the upper horizontal wall 33 and the flange 34 define a recessed portion into which concrete can be poured during the casting of the slab so as to form a false concrete skim coat which, as described in the previous embodiment, can be easily broken away from the main body of the cast splayed panel when the sideform 30 is removed from its formwork location.

WO 01/44600 PCT/AU00/01549 The upper and lower channel forming lips 38,39 permit a connector plate to be attached to the outer side wall of the sideform 30 which can then be connected to a sliding riser of a buttress support frame (not shown) of the kind described and illustrated in our Australian Patent No. 721582. It will be realised however, that the sideforms can be laterally braced by other means.

A brief consideration of the above described embodiment will indicate that the invention provides for a very simple and convenient arrangement for permitting concrete panels to be cast one on top of the other in a situation where a lower panel has an inwardly splayed edge, without any imprints or imperfections being formed in the cast face of a similar size panel cast on top of the lower splayed panel.

Claims (9)

1. A false splay sideform of hollow cross section for use in casting a splayed concrete panel as part of a stack of concrete panels cast one on top of the other, said sideform including a generally vertical outer side wall, an inner side wall extending at an inclined angle with respect to the outer side wall and which forms the splay angle of the sideform, and an upper wall extending between and interconnecting said inner and outer side walls, characterised by: an upwardly extending flange which forms a continuous extension of the inner side wall, said upwardly extending flange and said upper wall forming a recessed area on top of the sideform for receiving a skim coat concrete layer during casting of the splayed panel, the upper terminal edge of said flange being located below the upper edge of the sideform.

2. A false splay sideform according to claim 1 wherein said upwardly extending flange is integrally formed with the sideform.

3. A false splay sideform according to claim 1 wherein said upwardly extending flange forms part of a separate false splay strip removably attached to said upper wall of the sideform.

4. A false splay sideform according to any one of claims 1 to 3 wherein the upper terminal edge of said upwardly extending flange locates approximately 2 mm below the top surface of the panel of the splay panel being cast. A false splay sideform according to claim 1 wherein said outer side wall projects vertically upwards beyond said upper wall, and wherein said recessed area extends almost entirely across the full width of the top end of the sideform.

WO 01/44600 PCT/AU00/01549 7

6. A false splay sideform according to claim 1 wherein said upper wall has a stepped configuration, and said recessed area extends only part way across the width of the top end of the sideform.

7. A false splay sideform according to claim 3 wherein said separate false splay strip is bent so as to form a horizontal flange portion and an upwardly inclined flange portion which extends at the same splay angle as the sideform, said horizontal flange portion being arranged to slidably locate in a laterally inwardly opening slot defined by a slot forming flange integrally formed with said upper wall intermediate the ends thereof.

8. A false splay sideform according to any one of the preceding claims wherein said sideform is an extruded metal section.

9. A false splay sideform according to any one of the preceding claims wherein said recessed area has a depth of approximately 20 mm.