GB2298889A

GB2298889A - Wall tie

Info

Publication number: GB2298889A
Application number: GB9604805A
Authority: GB
Inventors: Alastair Aitken Sinclair; Alan Lang
Original assignee: ITW Ltd
Current assignee: ITW Ltd
Priority date: 1995-03-14
Filing date: 1996-03-07
Publication date: 1996-09-18
Anticipated expiration: 2016-03-07
Also published as: GB9604805D0; GB9505099D0; GB2298889B

Abstract

A method of repairing or reinforcing a wall, and a wall tie for repairing or reinforcing a wall, the tie having an elongate bar which is received in a slot bridging the area of the wall to be repaired or reinforced. The tie also includes fixing means (3), such as bent portions, at each end of the elongate bar to allow the tie to be anchored to the wall.

Description

TIE The present invention relates to a wall tie, and in particular to a wall tie for use in repairing or reinforcing building structures.

After a wall is built, it is often necessary to introduce in-plane bending strength of the wall, or to provide a lateral tying restraint to repair damage caused to the wall. Such damage may result due to consolidation of the underlying sub-soils, frost heave, structural failure of the foundations, swelling of sensitive clay subsoils, mining subsidence and the like. Where such damage occurs, it is known to introduce reinforcement into the wall to prevent further damage.

Where the damage results in cracks in the wall, ties are used to stitch the two sides of the crack together. In this case a slot is formed across the crack in the wall.

A straight metal bar is provided in the slot, and the slot filled with mortar, thereby retaining the bar within the wall. The bar acts to help reinforce the damaged portion of the wall, and to help resist further forces to reduce further damage.

Where the damage is to a lintel or wall portion above an opening, which may for example result in the failure of the lintel, ties are used above the damaged portion to absorb the vertical load. In this case, a slot is provided above the damaged portion in which the metal bar is retained. This helps prevent further damage.

The slot must be formed deeply into the wall to give the required reinforcement. A problem with this system is that forces may cause the wall to move relative to the reinforcing bar, and in this case, the bar does not adequately reinforce the wall. Further damage to the wall structure may therefore occur.

According to a first aspect of the present invention, a wall tie for repairing or strengthening a wall comprises an elongate bar, each end of the bar including a fixing means arranged to allow the ends of the tie to be anchored to the wall.

By including a fixing means at each end of the wall tie, each end is securely anchored to the wall, and therefore is able to withstand a large tension force in the wall. The force which can be withstood is greater than a conventional straight reinforcing bar with which slippage may occur between the wall and the bar.

It is preferred that each fixing means is in the form of a bent portion extending in a directed substantially perpendicular to the elongate bar. In this case, the wall tie is generally C-shaped. With this arrangement, the tie can easily be secured to the wall in such a way that tension forces in the wall are withstood. It is advantageous if the bent portions of the tie include a keying surface arranged to improve the anchorage of the tie to a wall. Preferably, further keying surfaces are provided along the length of the elongate bar. The keying surfaces may be in the form of one or more of threads, projections or detents formed on the surface of the end portions of the tie.

Preferably, the tie is made from metal, and in particular from a corrosion resistant metal, such as stainless steel. Such material is strong for withstanding the forces within a wall.

The elongate bar preferably has a length able to bridge the area of damage within the wall. Typically, the elongate bar has a length of 600 to 700 mm. Where the wall tie is to be used to reinforce damage occurring above an opening, the tie is preferably longer than the width of the opening, and more preferably is at least 400 mm longer than the width of the opening. The thickness of the bar depends on the forces which must be withstood, and the material from which the bar is made. Typically, the bar should have a thickness of between 5 and 8 mm.

According to a second aspect of the present invention, a method of repairing a wall or lintel using the wall tie of the first aspect of the present invention comprises the steps of forming a slot in the wall bridging the area to be repaired, the length of the slot being substantially equal to the length of the elongate bar, forming a recess at each end of the slot, the recess arranged to receive the fixing means of the wall tie, and anchoring the fixing means within the recess.

By securely anchoring each end of the wall tie within the wall, relative movement between the wall and wall tie is prevented.

The slot may be formed across the damaged area, or over the damaged area. Where the damage is to a wall or lintel over an opening, the slot is preferably formed over the damaged area. In this way, a wall tie provided with a slot resists a vertical load.

Where the wall tie is C-shaped, the recesses formed in the wall are preferably holes drilled into the wall substantially perpendicular to the surface of the wall. In this case, the ends of the wall tie may be secured in the holes by an adhesive, for example a resin, such as READY FIX (Trade mark) made by ITW Limited - Redhead Division.

Advantageously, the slot formed in the wall has a depth of approximately 25 mm. This makes repair of the wall easier than where a deep slot is required. Due to the bent end portions of the tie, the effective depth of the tie in the wall is much greater than the depth of the slot.

The present invention will be described in accordance with the accompanying drawings in which: Figure 1 shows a wall tie according to the present invention; and, Figure 2 shows the wall tie of Figure 1 in a wall.

As shown in Figure 1, the wall tie comprises an elongate stainless steel bar 1, the ends of which are bent perpendicular to the elongate bar 1, to form bent ends 2, 3. Each of the ends is provided with a number of small projections 4 together with a threaded portion 5 which act as keying means. The ends 2, 3 project approximately 50 mm from the bar 1. Additional keying means 6 may be provided along the length of the elongate bar 1.

To repair a wall 10, a slot 11 is formed in the wall 10 across the area to be repaired. The slot 11 is substantially the same length as the elongate bar 1 of the wall tie. The slot 11 has a depth of around 25 mm to fully receive the elongate bar 1 . Two 12 mm diameter holes 12 having a depth of 70 mm are formed at either end of the slot 11, the holes 12 extending perpendicular to the face of the wall 10. The wall tie is positioned in the slot 11, with each of the bent ends 2, 3 extending into the holes 12. The elongate bar 1 bridges the crack or other damaged portion in the wall 10.

The holes 12 in the wall 10 are filled with a resin adhesive (not shown) which sets to anchor the wall tie in the holes 12. The keying surfaces 4 on the ends of the wall tie act to improve the anchorage of the wall tie within the holes 12.

Finally, the slot 11 in the wall 10 is filled with mortar. This gives a clean finish to the repair. Where keying means 6 are provided, resin may be introduced in the slot 11 in the region of these keying means 6 to assist in the anchorage of the wall ties. This is done before the slot 11 is filled with mortar.

With this arrangement, the wall tie bridges the damaged portion of the wall 10, and is anchored securely to the wall 10 on either side of the damaged portion.

Accordingly, this prevents further damage to the wall.

Where the damage is to a wall portion or a lintel above an opening in the wall, the slot is formed above the damaged portion. This ensures that the wall tie is able to resist vertical loads which may otherwise further damage the wall or lintel.

Claims

CLAXMBt

1. A wall tie for repairing or strengthening a wall, the wall tie comprising an elongate bar, each end of the bar including a fixing means arranged to allow the ends of the tie to be anchored to the wall.

2. A wall tie according to claim 1, in which each fixing means comprises a bent portion extending in a directed substantially perpendicular to the elongate bar.

3. A wall tie according to claim 2, in which the bent portions of the tie include a keying surface arranged to improve the anchorage of the tie to a wall.

4. A wall tie according to any one of the preceding claims, further comprising keying surfaces along the length of the elongate bar.

5. A wall tie according to claims 3 or 4 in which the keying surfaces comprise one or more of threads, projections or detents formed on the surface of the tie.

6. A wall tie according to any one of the preceding claims in which the tie is made from metal.

7. A wall tie according to claim 6, in which the wall tie is made from a corrosion resistant metal.

8. A wall tie according to any one of the preceding claims, in which the elongate bar has a length of 600 to 700 mm.

9. A wall tie according to any one of the preceding claims in which the elongate bar has a thickness of between 5 and 8 mm.

10. A method of repairing a wall or lintel using the wall tie according to any one of the preceding claims, the method comprising the steps of forming a slot in the wall bridging the area to be repaired, the length of the slot being substantially equal to the length of the elongate bar, forming a recess at each end of the slot, the recess arranged to receive the fixing means of the wall tie, and anchoring the fixing means within the recess.

11. A method according to claim 10, in which the slot is formed either across the damaged area, or over the damaged area.

12. A method according to claims 10 or 11, in which the fixing means comprises a bent portion extending in a direction substantially perpendicular to the elongate bar, and in which holes are drilled into the wall substantially perpendicular to the surface of the wall to form the recesses.

13. A method according to claim 12, in which the ends of the wall tie are secured in the holes by an adhesive.

14. A method according to any one of claims 10 to 13 in which the slot formed in the wall has a depth of approximately 25 mm.

15. A wall tie as shown in, or described with respect to, the accompanying drawings.

16. A method of repairing a wall as described with respect to the accompanying drawings.