IES20080203A2 - A wall unit - Google Patents

Abstract

A wall unit comprises a set of substantially parallel elongated vertical wall ties having opposite edges which are substantially coplanar on each side of the set so as to define two substantially parallel planes containing said edges. A reinforcing mesh is recessed into the wall ties on each side of the set of wall ties by being set into slots in the wall tie edges. Formwork panels are adhesively and/or mechanically secured to the substantially coplanar wall tie edges on each side of the set of wall ties. The gap between the panels is filled with concrete. <Figure 4>

Description

This invention relates t necessarily, a pre-fabricated wall unit.

A type of wall construction is known in which formwork panels are mounted vertically upright and parallel to one another on a solid concrete floor, and the gap between the two filled with concrete. When the concrete is set the formwork panels may be removed, or left in place to form an integral part of the wall. In the latter case they are known as permanent formwork panels and are typically made of cement - see, for example, WO 2004/091903.

It is an object of the invention to provide an improved wall unit for use in this type of construction, as well as a method of manufacturing such a wall unit and a wall tie for use in the construction of such a unit.

According to the present invention there is provided a wall unit comprising a set of substantially parallel elongated wall ties having opposite edges which are substantially coplanar on each side of the set so as to lie in two substantially parallel planes containing said edges, at least one reinforcing mesh recessed into the wall ties on at least one side of the set by being received in slots in the wall tie edges on that side of the set, and at least one formwork panel secured to the substantially coplanar edges on each side of the set of wall ties.

The invention further provides a method of manufacturing a wall unit comprising assembling a set of substantially parallel elongated wall ties having opposite edges which are substantially coplanar on each side of the set so as to lie in two substantially parallel planes containing said edges, S0?03 recessing at least one reinforcing mesh into the wall ties on at least one side of the set by inserting the mesh in slots in the wall tie edges on that side of the set, and securing at least one formwork panel to the substantially coplanar edges on each side of the set of wall ties.

The invention further provides a wall tie for spacing opposite substantially parallel formwork panels in a wall unit, the wall tie comprising an elongated member with substantially parallel opposite flat longitudinal edges for retaining a formwork panel, each edge having a plurality of slots which intermittently interrupt the edge to allow a reinforcing mesh to be recessed into the wall tie clear of the edge.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows on the LHS a side view and on the RHS a perspective view of a wall tie used in the construction of a wall unit according to the embodiment.

Figure la is a horizontal cross-section through the set of vertical wall ties shown in Figure 2 which is used as the starting point in the manufacture of a wall unit according to the embodiment.

Figures 2 to 8 are perspective views of a wall unit according to the embodiment in successive stages of manufacture.

Figure 9 is a schematic plan view illustrating a T-shaped join between wail units.

Referring to Figure 1, a wall tie 10 used in the construction of a wall unit according to the embodiment comprises an ,£°8 02q3 elongated member 12 having a generally I-shaped cross-section with substantially parallel opposite flat longitudinal edges 14. The member can be formed from metal including steel or aluminium or from a polymer, for example, PVC or composite material according to the engineering requirements for the wall unit. Each edge 14 has a plurality of slots 16 which intermittently interrupt the edge at regular intervals to allow a reinforcing mesh to be recessed into the wall tie clear of the edge 14, as will be described. The wall tie 10 also has a plurality of apertures 18 distributed along its length between the opposite edges 14, and a short tab 20 at each end allows the lower end of the wall tie, when assembled into a wall unit with like ties as will be described, to locate between a pair of parallel floor-mounted support rails of the kind described in Irish Patent Application No. S2008/0091.

Referring now to Figures la and 2, the first stage in manufacturing the wall unit is to assemble a set of substantially vertical wall ties 10 side-by-side and substantially parallel to one another. Preferably, the ties are loaded into a floor mounted magazine and thereafter held in place in the temporary state by a jig (not shown) from which they depend in spaced apart relationship. The wall· ties 10 have their opposite edges 14 substantially coplanar on each side of the set of wall ties so that all the edges 14 on one side of the set lie substantially in a first plane Pl (Figure la) and all the edges 14 on the other side of the set lie substantially in a second plane P2, the planes Pl, P2 being substantially parallel to one another. Also, the apertures 18 in adjacent wall ties are horizontally aligned.

Next, Figure 3, vertical steel reinforcing rods 22 are inserted between adjacent wall ties 10 so as to extend substantially parallel to the wall ties along the opposite vertical edges of a rectangular window opening 24 (Figure 8) subsequently formed in the set of wall ties. The rods 22 are secured to the wall ties 10 by twisted wire.

Then, Figures 3 and 4, a respective rectangular steel mesh 26 having a vertical pitch the same as the spacing of the slots 16 and a horizontal pitch the same as the spacing of the wall ties 10, is set into the slots 16 on each side of the set of wall ties (only one mesh is shown in Figure 3). In particular, each horizontal· rod 28 of the mesh 26 enters a respective set of horizontally aligned slots 16, while each vertical rod 30 enters the gap between a pair of adjacent wall ties 10. Thus each mesh is recessed into the wall ties 10 behind, i.e. clear of, the opposite flat edges 14.

Next, Figure 4, horizontal steel reinforcing rods 32 are inserted through the aligned apertures 18 so as to extend along opposite horizontal edges of the rectangular window opening 24 (Figure 8) subsequently to be formed. The rods 32 are secured to the wall ties 10 and/or to the mesh 26 by twisted wire. At his point the vertical steel reinforcing rods 22 can also be secured to the mesh.

Now, Figure 5, each side of the wall tie assembly is covered with edge-to-edge abutting cement formwork panels 34 which are adhesively and/or mechanically secured to the substantially coplanar wall tie edges 14 on each side of the set of wall ties. Preferably, a polyurethane based adhesive may be used, although it will be seen that any fixing mechanism can be employed including screws. In the case where a rectangular opening is to be formed in the finished wall unit, the panels 34 are pre-cut to define the periphery of the opening, as indicated at 36. Next, pull-out bars 38 are slid into each end of the assembly. Each bar 38 has a pair of legs 40 which are slidably inserted into horizontally aligned slots 18 alongside respective horizontal mesh rods 28. The bars 38 may be pulled out to any desired extend from the end of the wall tie assembly, for a purpose to be explained.

Now the rectangular section 42 of wall ties 10 and mesh 26 revealed in the panel opening 36 is cut out, Figure 6, to form the window opening 24. A reveal 44 is now inserted into the opening 24 to close off the gap between the cut edges of the panels 34, Figures 7 and 8.

At this point the wall unit is complete except for its concrete filling, and is preferably pre-fabricated off-site and transported as a self-supporting unit to the construction site.

At the construction site the unit is located on a pair of parallel floor-mounted support rails of the kind described in the above co-pending patent application, the short tabs 20 at the bottom edge of the unit locating between the rails. When the unit is in its final position, a concrete filling is poured into the gap between the formwork panels 34 and allowed to set. To avoid the concrete escaping, the vertical gap between the panels 34 at the ends of the unit are closed off either by the unit abutting edge-to-edge against another such unit, with the gap between the two being permanently bridged by further cement board permanent formwork, or by the unit joining another wall at a T-shaped junction, for example as shown in Figure 9.

In Figure 9 three wall units 50a, 50b and 50c are shown meeting at a T-junction, prior to pouring the concrete filling. The units 50a and 50c are in-line and the vertical gap between their panels 34 are closed on one side by a permanent formwork panel 52, and on the other side by the unit 50b. The three units are coupled by their pull-out bars 38 8°203 which are wired together and become embedded in the concrete to reinforce the T-join.

Barcodes (or other machine-readable identifiers) are applied to the pre-fabricated wall units as they are produced and the units are shipped with their associated support rails which are also bar-coded, and associated formwork panels i.e. 52 When a rail is scanned on site with a handheld scanner attached to a PDA on which a model of the building is either stored or accessible across a network, the PDA can display where the rail is to be fixed on the ground. Similarly before being placed in position, the formwork panel and rail can be scanned to ensure they are properly located and also to update the progress of the construction through the PDA. Also this methodology is also applied to the formwork pieces that close voids 52 and enables correct assignment and alignment of same.

The number of parallel side-by-side wall ties 10 in a particular wall unit, as well as their length and the distance between their opposite edges, may be varied according to the required dimensions of the wall unit.

The invention is not limited to the embodiment described herein which may be modified or varied without departing from the scope of the invention.

Claims (5)

Claims:

1. A wall unit comprising a set of substantially parallel elongated wall ties having opposite edges which are substantially coplanar on each side of the set so as to lie in two substantially parallel planes containing said edges, at least one reinforcing mesh recessed into the wall ties on at least one side of the set by being received in slots in the wall tie edges on that side of the set, and at least one formwork panel secured to the substantially coplanar edges on each side of the set of wall ties.

2. A wall unit as claimed in claim 1, further including apertures in the wall ties which are aligned in a direction substantially normal to the longitudinal direction of the wall ties, and at least one reinforcing rod extending through the apertures along an edge of a rectangular opening in the set of wall ties.

3. A wall· unit as claimed in claim 1 or 2, further including at least one reinforcing rod extending substantially parallel to and between adjacent wall ties along an edge of a rectangular opening in the set of wall ties.

4. A wall unit as claimed in claim 1, 2 or 3, wherein each wall tie has a generally I-shaped cross-section.

5. A wall unit as claimed in any preceding claim, having a concrete filling in the gap between the formwork panels.