CONSTRUCTION

TECHNICAL FIELD The present invention relates to the field of construction and more specifically relates to pre-cast concrete formwork, a wall system and an associated method of forming a wall system in a structure.

BACKGROUND

Any references to methods, apparatus or documents of the prior art are not to be taken as constituting any evidence or admission that they formed, or form part of the common general knowledge. The use of formwork which interconnect to form a wall structure into which concrete can be poured is known.

Traditionally concrete walls have been cast by using double skin formworks. In recent years, a variety of new systems have been developed to enhance the quality of the construction works.

Tilt-up concrete panels for example have been used extensively. Another type of pre-cast wall panel includes the use of double skin walls which comprises two reinforced concrete skins, each of which is 50 to 70 mm thick. Each of the double skins is connected to each other via a 3D truss of reinforcing bars. The gap between the skins is filled with concrete on site to shape a semi-monolithic structure.

There is a need for providing improved formwork and a wall system that reduces the overall time required for construction and also provide a higher quality finish. There is also a need to provide modular formwork which can be configured into one of many possible configurations to allow building of varying dimensions to be built more easily. SUMMARY OF THE INVENTION

In one aspect, the invention provides formwork for building a wall system, the formwork comprising:

a first pre-cast concrete wall panel and a second pre-cast concrete wall panel, the first wall panel being adapted for being positioned in a spaced relationship with the second wall panel;

a hollow core defined by oppositely arranged surfaces of the first and the second wall panels, the core being adapted for receiving wet concrete; and

a connecting arrangement for inter-connecting the first wall panel with the second wall panel in the spaced relationship, the connecting arrangement extending generally in an outwardly direction relative to said oppositely arranged surfaces of the first and second wall panels. In an embodiment, each of the first and second panels comprises a substantially regular or irregular cross section (included but not limited to trapezoidal, circular, square, rectangular, elliptical, or a combination of these) having a plurality of summit portions spaced apart from each other by furrow portions and wherein during use the summit portions are located along the oppositely arranged surfaces of the first and second panels.

Preferably, during use, a first plurality of summit portions of the first panel are arranged in an opposed relationship relative to a second plurality of the summit portions such that each of the summit portions of the first panel is positioned adjacent a corresponding summit portion of the second panel to provide the connecting arrangement.

In an embodiment, the formwork further comprises a spacer for being positioned and retained in between respective summit portions of the first and second panel during use.

In an embodiment, a first plurality of furrow portions from the first panel are positioned in an opposed relationship relative to a second plurality of furrow portions of the second panel such that each of the furrow portions of the first panel and a corresponding furrow portion of the second panel defines a hollow core portion to receive fresh concrete poured therein.

In an embodiment, lateral edge portions for each of the panels comprises profiled projections such that thickness of the projections is preferably less than the height of one or more of said summit portions to accommodate one or more joining members for inter-connecting a first pair of said first and second panels with a second pair of said first and second panels along their respective lateral edge portions.

In an embodiment, the projecting portions of the first panel are spaced apart from the oppositely arranged projecting portions of the second panel to define a grout receiving cavity. In an embodiment, the joiner members extend in a transverse direction relative to the length of the summit portions.

In an embodiment the formwork further comprises a plurality of spaced apart joiner members positioned in between the top and bottom portions of the panels, said joiner members further comprising one or more respective receiving portions that are aligned for receiving one or more reinforcing members extending in a generally upright direction.

In an embodiment, each joiner member comprises a first receiving portion and a second receiving portion such that the first receiving portion for each of the joining members are aligned to receive a reinforcing member in between the oppositely arranged surfaces of the first pair of panels and the second receiving portion for each of the joining members are aligned to receive a reinforcing member in between the oppositely arranged surfaces of the second pair of panels.

In an embodiment, the joiner member is structured to allow a first structural wall formed by the first pair of panels to lies in a first imaginary plane that intersects a second imaginary plane of a second structural wall formed by the second pair of panels. In an embodiment, the formwork further comprises locking members for locking the joining members to at least one of said oppositely arranged surfaces.

In an embodiment, the formwork further comprises an elongate capping member for being positioned along oppositely arranged lateral edges of the first and second panels wherein an internal wall of the capping member and the projecting portions of the first and second panels define an internal space for receiving grout or fresh concrete. Preferably, the capping member comprises an inter-locking arrangement for interlocking the capping member with the lateral edges of the first and second panels.

In an embodiment, the formwork further comprises an additional joining member extending outwardly from an internal surface of the capping member into the core portion for inter-connecting the capping member with the first and second panels wherein the additional joining member comprises receiving portions for receiving one or more reinforcing members extending in a generally upright direction.

In an embodiment, the formwork further comprises one or more additional reinforcing members extending through the core, the reinforcing members extending in an outwardly direction, preferably in a vertical direction relative to a supporting surface supporting the first and second wall panel.

In an embodiment, the formwork further comprises a lintel member for being positioned above in-use upper portions of the first and second panels, the lintel member further comprising connecting members for connecting the lintel member to the core of the formwork. To minimize the weight of the lintel member, internal cavities may be provided. In an embodiment, the formwork further comprises reinforcing bars extending along the length of the lintel member wherein an in-use upper portion comprises a first plurality of reinforcing bars and in-use lower portion comprises a second plurality of reinforcing bars. In another aspect, the invention provides a pre-cast concrete panel to construct formwork for a wall system in a building, the panel comprising a substantially regular or irregular cross section (included but not limited to trapezoidal, circular, square, rectangular, elliptical, or a combination of these) having a plurality of summit portions spaced apart from each other by furrow portions wherein two of said panels can be oppositely arranged to position the summit portions of each panel in a connected configuration and wherein the furrow portions of the oppositely arranged panels define a plurality of hollow cores for receiving fresh concrete therein.

In another aspect, the invention provides a method of constructing a wall in a structure, the method comprising:

positioning a first pre-cast concrete wall panel in a spaced relationship from a second pre-cast concrete wall panel, the first wall panel being adapted for being positioned in a spaced relationship with the second wall panel;

connecting the first wall panel with the second wall panel to maintain the first and second wall panels in the spaced relationship wherein the connecting arrangement extends generally in an outwardly direction relative to said oppositely arranged surfaces of the first and second wall panels; and

pouring wet concrete into a core defined by oppositely arranged surfaces of the first and second wall panels.

In an embodiment, at least one of the wall panels comprises cavities or channels extending along said panels in a generally upright direction for accommodating one or more supply lines during use.

In another aspect, the invention provides a wall system including formwork in accordance with the first aspect and wet concrete poured into the core thereby forming the wall system.

In an embodiment, the wall panels are adapted for receiving fagade panels and/or internal wall panels. In an embodiment, the formwork comprises a first plurality of the wall panels comprising one or more of the first wall panels and a second plurality of the wall panels comprising one or more of the second wall panels wherein the first plurality of wall panels is in a spaced relationship from the second plurality of wall panels.

In an embodiment, the formwork further comprises an anchoring member for anchoring the first and/or second plurality of wall panels to a supporting surface. BRIEF DESCRIPTION OF THE DRAWINGS

Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows:

Figure 1 A illustrates a pre-cast concrete panel 180 used in formwork for building a wall system in a building in accordance with an embodiment of the present invention.

Figure 1 B is a sectional view of the pre-cast concrete panel 180. Figure 2A illustrates formwork system 190 for building a wall in a building in accordance with an embodiment of the present invention in accordance with a first formwork embodiment of the present invention.

Figure 2B illustrates formwork system 190' for building a wall in a building in accordance with an embodiment of the present invention in accordance with a second formwork embodiment of the present invention.

Figure 2C illustrates a sectional side view of the formwork system 190. Figure 2D illustrates a sectional top view of the formwork system 190.

Figure 2E illustrates a sectional top view of the formwork system 190'. Figures 2F to 2H illustrate perspective views of the external face of formwork 190 or 190' where new suspended scaffolding system are installed.

Figure 3A illustrates a continuous wall 500 built using a plurality of formwork systems 190.

Figure 3B illustrates a continuous wall 500' built using a plurality of formwork systems 190'.

Figure 4A is a sectional view of a T shaped wall structure 280 comprising formwork systems 190 and 190'.

Figure 4B is a sectional view of another T shaped wall structure 280' comprising formwork system 190. Figure 4C is a sectional view of another T shaped wall structure 280" comprising formwork systems 190 and 190'.

Figure 4D is a sectional view of another T shaped wall structure 280"' comprising formwork system 190.

Figure 5A is a sectional view of an L-shaped wall structure 290 comprising formwork system 190.

Figure 5B is a sectional view of another L-shaped wall structure 290 comprising formwork systems 190 and 190'.

Figure 5C is a sectional view of an L-shaped wall structure 290" comprising formwork system 190'. Figure 6A is a perspective view of a lintel member 200 in accordance with an embodiment.

Figure 6B is a sectional view of the lintel member 200.

Figure 7A is a perspective view of a lintel member 200' in accordance with an embodiment.

Figure 7B is a sectional view of the lintel member 200'.

Figure 8A is a perspective view of a capping member 210 in accordance with an embodiment.

Figure 8B is a sectional view of the capping member 210.

Figure 8C is an in-use sectional view of the capping member 210.

Figure 9A is a perspective view of a capping member 210' in accordance with an embodiment.

Figure 9B is a sectional view of the capping member 210'.

Figure 9C is an in-use sectional view of the capping member 210'. Figure 10A is a perspective view of a window sill unit 220 in accordance with another embodiment.

Figure 10B is a sectional view of the window sill unit 220. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to Figure 1 , a first embodiment of the invention provides a single skin pre-cast concrete panel 180 which has a corrugated or trapezoidal cross section. The pre-cast panel 180 comprises a plurality of summit portions 181 that are separated or spaced apart by cavities or furrows 182 extending along a generally vertical direction of the panel 180 at the inner face. The outer face of the panel 180 also comprises non-continuous furring channels 187 to shape voids 186 in the horizontal direction. The cavities furring channels 187 and the voids 186 have been provided for housing service lines such as electrical conduits 183 and plumbing supply lines such as hot water pipes 184 and cold water pipes 185. The horizontal voids 186 also allow the conduits and pipes to be positioned in the horizontal direction when required.

The pre-cast wall panel 180 is also adapted for receiving an outer plasterboard panel 189 on an outwardly facing surfaces of the pre-cast panel 180. The cavities formed by the furring channels 187 makes each panel 180 lighter while assisting with installation of pipes and electrical conduits. The single skin pre-cast concrete panel 180 may have a width that varies from 200 mm to 2600 mm at 50mm intervals. In relation to height, the panels may be provided in a range of heights such as 1 100 mm (to be used under the window), 2400 mm, 2700 mm, 3000 mm, 3200 mm, 3600 mm, and 4000 mm. The thickness of the single skin pre-cast concrete panel 180 in some embodiments may be limited to 75 mm and the body of the panel may contain reinforcing mesh 188 in the concrete body of the panel 180 (as shown in Figure 1 B).

Figures 2A and 2B illustrate formwork systems 190 and 190' that may be assembled by using at least two of the panels 180 as described in the previous passages. Each of the formwork systems 190 and 190' comprise two spaced apart pre-cast concrete panels 180A and 180B. A hollow core is defined by oppositely arranged surfaces of the first and second wall panels 180A and 180B, the core being adapted for receiving wet concrete. As described in the earlier sections, each of the oppositely arranged surfaces of the panels 180A and 180B comprises summit portions 181 that provide a connecting arrangement for inter- connecting the panels 180A and 180B during use. A first plurality of summit portions 181 A of the first panel are arranged in an opposed relationship relative to a second plurality of the summit portions 181 B such that each of the summit portions 181 A of the first panel 180A is positioned adjacent a corresponding summit portion 181 B of the second panel to provide the connecting arrangement. Similarly, a first plurality of furrow portions 182A from the first panel 180A are positioned in an opposed relationship relative to a second plurality of furrow portions 182B of the second panel 180B such that each of the furrow portions of the first panel 180A and a corresponding furrow portion of the second panel 180A defines a hollow core portion to receive fresh concrete poured into the hollow core.

The formwork system 190 (shown in Figure 2A) uses spacer members 195 for positioning the summit portions 181 A and 181 A from the oppositely arranged panels 180A and 180B in a spaced apart configuration. The spacer member 195 extends generally along a vertical directions relative to the inner surfaces of the first and second pre-cast panels 180A and 180B.

The formwork system 190' (shown in Figure 2B) does not use any spacer members. Consequently, oppositely arranged summit portions 181 A and 181 B may be directly fastened to each other. In formwork 190', the summit portions 181 A and 181 B are directly connected to each other via surface connection 198 using structural adhesive. The wall unit 190 also contains 6mm thick slots 197 arranged along the side walls of each furrow portions 182 that enable separation of the vertical cavity cores using steel, PVC, or cement sheet.

Referring to Figures 2D and 2E, lateral edge portions for each of the panels 180A and 180B comprises profiled projections 191 such that thickness of the projections 191 is less than the height of one or more of said summit portions 181 to accommodate one or more joiner members 196 for inter-connecting a first pair of said first and second panels 180A and 180B with a second pair of said first and second panels 180 along their respective lateral edge portions.

During a typical installation a plurality of formwork systems 190 or 190 'may be inter-connected or joined with each other to form a continuous wall in a building as shown in Figures 3A and 3B. Referring to Figures 3A and 3B, a plurality of joiner members 196 are positioned in between the top and bottom portions of the pairs of oppositely arranged pre-cast panels. Referring to Figure 3A for example, three pairs of pre-cast panels are arranged in a side by side manner for forming a wall section in a structure. A first pair of oppositely arranged per-cast panels 180A and 180B is inter-connected to a second pair of oppositely arranged per-cast panels 180P and 180Q by utilizing the plurality of joining member 196. Each of the joiner members 196 further comprising one or more receiving apertures 196A. The apertures 196A for each of the joiner members inter-connecting the two adjacently located pairs of pre-cast panels 180A and 180B are aligned for receiving reinforcing members 193 extending in a generally upright direction. In addition, vertically oriented reinforcing bars 193 extending through the core 192 are also provided. Similarly, locking ladder shape reinforcing bar 193 and 196' is used to connect adjacent wall units 190'. Additional reinforcing bars 193 may also be positioned in the core of the oppositely arranged panels 180A and 1 80B.

Figures 2F and 2H illustrate perspective views of the external face of formwork 190 and 190' where new scaffolding system 198 can be installed. To ease safe access to the external face of the wall units, the wall units are equipped with cast- in-ferrules 197. A cantilevered T section steel beam 1000 with end connecting plate 1001 are connected to the wall via a bolted connection 1002. The other side of the cantilevered T section contains an upwardly circular, square, or rectangular hollow sections 1003 that acts as balustrade. The traditional aluminum, steel or timber plank unites 1004 are then place over the cantilevered T section to shape a safe pass for construction workers. These can be connected to the supporting T section steel beam by screws, bolts or pins.

Figures 3A and 3B illustrate sectional views of formwork systems 190 and 190' in an external load bearing wall using spaced apart pairs of pre-cast wall panels 180 internal gap (Figure 3A) and without internal gap (Figure 3B). The size and number of the joining members 196 for interconnecting the various pairs of wall panels 180 depends on the structural integrity of the external load bearing wall. In both the walls 190 and 190', the edge cavity cores (cores defined by the projections 191 located along the lateral edge portions of each panel 180 that are inter-connected in a side by side arrangement) may be grouted on site. The number and size and arrangement of vertical reinforcing bars 194 depends to the structural adequacy of the wall to withstand the applied loads. Hence, the internal cavity cores 192 may be grouted or kept empty depending on the load bearing requirements. Referring to Figures 4A to 4D and Figures 5A to 5C, typical T and L shaped wall formations can be constructed using the formwork systems 190 and 190'. Joiner members of varying configurations such as the joiner units 280, 280', 280", 280"', 290, 290', and 290' may allow two, three, or four adjacently located wall units to be positioned at various angles including but not limited to 90 degrees. All such joiner units may comprise wet connections (in-situ concrete / grout) and either a T shaped (281 ) or L shaped (291 ) reinforcing connectors that can been located around a vertical bar (283) located at the centre of the connector. The number and size of the L shaped and T shaped connectors (281 or 291 ) and the number of reinforcing bars (such as 283) depends on the magnitude of applied loads on the wall formation. In the presence of internal gap between the pre-cast concrete panels when formwork system 190 is utilised, a small to medium size reinforcing cage 282 or 292 may be utilized. To keep the reinforcing connectors 281 or 291 in the correct horizontal alignments, a locking arrangement in the form of metal or PVC lockers 284 may be used at the inner face of the edge voids of the pre-cast panels used in the formwork systems 190 or 190'.

Figures 6A, 6B, 7A and 7B illustrate sectional and perspective views of lintels 200 and 200' that are configured for being positioned over the opening areas (doors and windows) in the walls built using formwork systems 190 and 190'. The lintels 200 and 200' may span in between capping members in the form of termination units 210 and 210' (shown in Figures 8 and 9) above an upper portion of the formwork system 190 or 190'. The lintel 200 and 200' is provided with positive reinforcing bars 201 within a lower portion of the lintel and negative reinforcing bars 202 located along the upper portion of the lintel 200 and 200'. Shear ligatures 203 are also provided along the length of the lintel 200 and 200' connecting the top reinforcing bars 202 to the bottom reinforcing bars 201 . To minimize the weight of the lintels 200 and 200' internal cavities may be provided. In order to prevent any out of plane movement, a shear connector 205 may also be provided at both ends of the lintels 200 and 200'. The shear connector 205 may be located within the cavity of the wall units 190 and 190', and can be secured in its position using grout or concrete. The lintel unit 200' also contains an upwardly extending portion 206 having a thickness of less than 60 mm that contains reinforcing mesh 204. This upwardly extending portion 206 may function as edge formwork to prevent the fresh concrete from escaping from the slab.

Referring to Figures 8A to 8C and 9A to 9C, embodiments of elongate capping members 210 and 210' are illustrated. The elongate capping members 210 and 210' are adapted for being positioned along oppositely arranged lateral edges of the first and second panels 180A and 180B wherein an internal wall of the capping member and the lateral edge portions of the panels 180A and 180B define an internal space for receiving grout or fresh concrete. The capping members 210 and 210' function as permanent formwork and may be positioned in place by way of forming connections with the pre-cast concrete panels 180A and 180B. These connections are formed using dry shear connectors 213 and 214, and wet connection at the vertical cavity of the wall via shear connectors 21 1 and a vertical bar 212 that restrain the shear connectors 21 1 . These connectors are provided for engaging connecting edges of the pre-cast panels used in the formwork systems 190 and 190'. The connectors 213 and 214 form connecting grooves (or tongue) for receiving corresponding tongue (or grooves) portions provided along an edge of the wall units 190 and 190'. Figuresl OA and 10B illustrate another embodiment of a capping member in the form of a window sill plate 220. The window sill plate member 220 is provided along a bottom portion of a window opening. The window sill plate 220 also functions as permanent formwork and is positioned in place by way of forming wet shear connections within the cores/cavities of walls built using formwork systems 190 and 190'. These connections may be formed by way of shear connectors 222. The window sill plate member 220 also contains a slot 223 at its soffit along its outer edge to eliminate water intrusion to the interface of the sill unit and the wall unit. The applicants believe that adopting a factory based system whereby all the parts of the formwork are pre-fabricated off-site at the factory reduces the potential of risk for construction workers because it is understood that the factory workers are highly skilled and better trained. As a result, the applicants believe that adopting the formwork as described in this document can minimise / eliminate of the majority of the risks associated with site constructions.

In at least some embodiments, it is expected that adopting the wall systems provided in this document is likely to provide the following advantages:

• Increase the speed of construction;

• Achieve high-quality finishes;

• Enhance safety of labours working on a building;

• Decrease construction cost;

• Decrease the volume of the on-site concreting;

• Decrease the amount of reinforcing bars that need to be placed and

arranged on-site;

• Enhance the quality of the concrete structure;

• Reduce the risk on third parties due to construction activity as the building will be constructed in short period of time (compared with the current construction time).

• Eliminate the use of a full scaffolding system as suspended scaffolding platform can be directly utilised in the wall system;

• Achieve good quality sound insulation;

• Can be combined with other thermal insulation to achieve high level of energy rating.

The use of the formwork as described in this document may provide the following non-limiting advantages:

• Possibly reduce the final cost of a concrete building because the use of formwork in conjunction with the present system is likely to be reduced and possibly eliminated;

• Minimum propping requirements for long spans and no propping required for short to medium spans. As a result, workers can easily and safely work in the floor with no obstruction (propping);

• Eliminate the use of a full scaffolding system as temporary scaffolding platform can be directly utilised in this invention; • Assembling formwork as described in this document is relatively straightforward and requires less effort from site workers;

• The systems are modular and can be used to build structures with different shapes.

It will be understood that any of the pre-cast panels may be built using reinforced or pre-stressed concrete or any other suitable materials whereby the strength of the materials can satisfy the loading scenarios (with or without any reinforcing bars).

In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. The term "comprises" and its variations, such as "comprising" and "comprised of" is used throughout in an inclusive sense and not to the exclusion of any additional features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted by those skilled in the art.

Throughout the specification and claims (if present), unless the context requires otherwise, the term "substantially" or "about" will be understood to not be limited to the value for the range qualified by the terms. Any embodiment of the invention is meant to be illustrative only and is not meant to be limiting to the invention. Therefore, it should be appreciated that various other changes and modifications can be made to any embodiment described without departing from the spirit and scope of the invention.