GB2145459A - Ties for existing cavity-wall constructions, e.g. panels or walls - Google Patents

Abstract

Tie 10, having collars 16, 18 is inserted into aligned bores 12, 14 in the skins, with one collar in each bore. An adhesive supply nozzle 50 is inserted into a wider section 22 of an axial supply passage 20 until it abuts an intermediate shoulder 26. Adhesive supplied through the nozzle 50 fills, via the narrower section of supply passage 20 and transverse openings 32, the space around the tie in skin 42 up to collar 16. The nozzle 50 is then withdrawn, and further adhesive is supplied via wider passage section 22 and openings 34 to fill the space in skin 40. The collars may have grooves 69 to allow air to be displaced during filling. <IMAGE>

Description

SPECIFICATION Constructional tie and method of installing the same This invention concerns a constructional tie, that is to say a tie intended to be incorporated into a building structure or component so as to tie together two adjacent (and usually spaced-apart) members, such as the inner and outer skins of a cavity wall or two spacedapart or confronting layers of a composite prefabricated or in-situ fabricated panel comprising two or more such layers.

Certain defects have recently become evident in certain system-built structures, such as blocks of flats, erected in the last ten to twenty years, using steel or concrete frames in combination with two-skin or two layer reinforced concrete cladding panels, which panels were constructed to have the skins or layers spaced apart either by a cavity or by a heatinsulating filling.

In the fabrication of such panels, mechanical (e.g. metal) ties were provided between the two concrete layers and their presence is essential to assure the integrity of the panel.

However, recent experience has been that the panels in some instances have started to disintegrate, the outer concrete skin breaking away and entire panels being found to lack integrity and being completely unserviceable. Investigations seem to point towards this being due to either absence of ties from the panels and/or to failure or corrosion away of the originally-installed ties. Absence of the ties may have arisen inadvertantly, or by an installer through ignorance of their essential nature or by accident, removing the same (e.g. by cutting them away) during the installation of the panels.

However the absence of effective ties may have come about, there now exists a very real need to be able effectively to reestablish the integrity of two-layered concrete panels of the kind just discussed, in situ, in order to arrest the detrioration of existing buildings, constructed therefrom, which in certain cases has progressed so far as to have caused some authorities to make decisions to demolish whole blocks of flats.

The present invention has for its object, therefore, to provide a constructional tie (and method of installing the same) by which this may be achieved, so that the concrete layers in such panels may be firmly retied relative to one another, such a tie being usable, of course, in other comparable environments such as between the two skins of a cavity wall constructed, e.g. of brickwork, breeze blocks or the like.

In the past, it has, of course, been known to adhesively secure fastening elements of various types in their respective boreholes by providing each element with a longitudinal supply passage and transverse openings leading therefrom so that adhesive injected into the supply passage will emerge into the borehole via the transverse openings. The constructional tie of the present invention is a development of this principle.

Pursuant hereto, the present invention provides a constructional tie as above referred to comprising an elongate element having an external surface or configuration with which a good adhesive anchorage in a borehole can be achieved, a spaced-apart pair of locators on said elongate element for locating the latter in a borehole in spaced-apart construction members or layers, with one of said locators in each said member or layer, an adhesive supply passage extending longitudinally of the elongate element and consisting of a relatively wide section extending from one end thereof to a shoulder and a relatively narrower section extending from said shoulder towards the other end thereof, and respective openings from the wide section and from the narrower section of the supply passage enabling adhesive to be supplied, after insertion of the elongate element into a borehole, to the exterior of the element selectively to the one side of one of the locators and then to the other side of the other of the locations.

The shoulder between the relatively wide and narrower sections of the supply passage allows for positive location of an adhesive supply nozzle inserted into the wide section of the supply passage so that the end of the borehole exterior to the narrower section can be filled with adhesive independently of the other end of bore exterior to the wide section.

Preferably the elongate element is in the form of a rod, which may be axially bored to provide the supply passage, and may be externally screw-threaded to provide for good adhesive anchorage.

In the latter instance, the locators are conveniently in the form of collars which may, for instance, be internally threaded to engage with the rod when the latter is screwthreaded.

These collars may be provided with spacedapart external axially-extending ribs or protrusion whereby the collars are a friction fit into the borehole whilst providing gaps or clearances through which air may be displaced upon introduction of adhesive.

Alternatively, these collars may simply be provided around their periphery with spaced apart axially extending grooves for displacement of air upon introduction of adhesive. The collars may be rigid. but alternatively may be formed of flexible material so as to be sufficiently adaptable to fit into bores of marginally different diameters.

The invention further provides a method of installing, in a building structure or component so as to tie together two adjacent members thereof, a constructional tie as above defined, said method comprising inserting the tie, with the relatively narrower section of its supply passage innermost, into a borehole, which extends through the first of said members and into the second of said members, until the tie reaches a position wherein the locators are disposed one in each of the said members, inserting an adhesive injecting nozzle into the wider section of the supply passage so that it engages the shoulder of the passage and inecting a setting adhesive through said nozzle so as to provide a first fill in the space outside the elongate element within the second of the members up to the locator disposed therein, and subsequently withdrawing the adhesive injecting nozzle and introducing further adhesive into the supply passage to provide a second fill in the space outside the elongate element within the first of the members up to the respective locator.

In carrying the method of the invention into effect, preferably the first adhesive fill is allowed or caused to set, and the security of the adhesion of the elongate element within the second member is tested prior to the introduction of the second adhesive fill.

Preferably, the adhesive fills are supplied as predetermined adhesive doses.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a sectional side elevation illustrating a first practical embodiment of the constructional tie of the invention inserted into position in a borehole in a two-layer prefabricated structural panel as a first stage in carrying out the installation method of the invention, the tie being shown in side elevation; Figure 2 is a view comparable with Fig. 1, but showing the tie in section and with an adhesive supply nozzle positioned ready for introducing a first fill of adhesive as a next stage in carrying out the method; Figure 3 is a view comparable with Fig. 2, showing the first adhesive fill having been introduced;; Figure 4 is a view comparable with Figs. 2 and 3, but showing another adhesive supply nozzle positioned ready for introducing a second fill of adhesive as a further stage in carrying out the method; Figure 5 is a view comparable with Figs. 2, 3 and 4, but showing the second adhesive fill having been introduced; Figure 6 is a view similar to Figs. 2 to 5, showing one of a number of ways in which the installed tie may be masked; Figure 7 is a sectional view illustrating a second practical embodiment of the constructional tie of the invention inserted into position in respective boreholes in inner and outer skins of a cavity wall with an adhesive supply nozzle positioned ready for introduction of a first fill of adhesive in accordance with the installation method of the invention;; Figure 8 is an end view of a locator of the second embodiment of the constructional tie of the invention; Figure 9 is a view comparable with Fig. 7 but showing another adhesive supply nozzle in position having been used for introducing a second fill of adhesive in accordance with the method of the invention; and Figure 10 is a side elevation of an adhesive supply nozzle suitable for use in carrying out the method of the invention.

Throughout the various figures. similar reference numerals have been allocated to simi lar parts.

As shown in Figs. 1 to 6 of the drawings.

first practical embodiment of the structural tie of the invention comprises an elongate element in the form of an externally-threaded rod 10, the external threading 1 2 of which serves (as will become evident later) to permit a good adhesive anchorage of the rod 10 into a borehole 14 to be achieved.

Disposed on the rod 10 so as to be spaced apart are two locators which in embodiment illustrated in Figs. 1 to 6 are internallythreaded collars 1 6, 1 8 which threadedly engage with the threading 1 2 on the rod 1 0. If desired, these collars 16, 18 may be prevented from moving along the rod 10, by reason of being rotated thereon,by means of radial pins or rivets (not shown in the drawings) through the collars 16, 1 8 engaging into the rod 10, so that they are positively held in a predetermined spacing.

Shallow longitudinal protrusions or ribs 1 9 are provided at intervals around both of the collars 10 16, 18.

As shown in Figs. 2 to 6, the rod has extending longitudinally thereof an adhesive supply passage, indicated generally by the reference numeral 20, and comprising an axially-extending bore including a relatively wide section 22 extending from the one end 24 of the rod 10 up to a shoulder 26 at a intermediate position about a third of the way along the rod 10, and a relatively narrower section 28 extending from the shoulder 26 right up to the other end 30 of the rod 10. First radial openings 32 (of which two only are visible in the drawings) connect the narrower section 28 of the supply passage with the exterior of the rod 10 near to the said other end 30 of the rod 10, and second radial openings 34 (of which, again two only are visible in the drawings) connect the wider section 22 of the supply passage with the exterior of the rod 10 near to the shoulder 26.

The successive Figs. 1 to 6 illustrate the various stages involved in the installation of the tie so as to anchor together two concrete members or components, namely first reinforced concrete layer or skin 40 and second reinforced concrete layer or skin 42 of a prefabricated constructional panel 44 which may, in practice, be in situ in a build struc ture. In the illustrated panel, the two layers or skins 40 and 42 are separated by an intermediate layer 46 of heat insulating material such as a rigid plastics foam and the second layer or skin 42 is faced with a skimming 48, e.g.

of plaster, since this skimming 48 will face inwards of a room defined by a wall of which the panel 44 forms part.

As a first step in the installation, the borehole of substantially constant diameter and of a depth related to the overall thickness of the panel 44 and the length of the rod 10 is bored into the panel so as to extend right through the first layer or skin 40 and only part way through the second layer or skin 42.

This may be effected, for instance, using a percussion drill. Thereupon, the tie is introduced into the borehole 14, end 30 first, and is tapped in as far as possible, to the illustrated position in which the collar 1 6 is a friction fit in the blind . art of the borehole 14 within the second layer or skin 42 of the panel 44, close to where such part of the borehole 14 meets with the insulating layer 46, and the collar 1 8 is correspondingly just closing the inner end of that part of the borehole which extends through the first layer or skin 40, where such part meets with the insulating layer 46. Although the collars 16, 18 fit frictionally in the respective borehole parts, this is achieved by contact therewith of the protrusions or ribs 19, so that there is a possibility of air escaping from the inner parts of the borehole.

The tie having been inserted in place, as shown diagrammatically in Fig. 2, a nozzle 50 of an adhesive injecting tool (not shown) is introduced into the wider section 22 of the adhesive supply passage 20 until it contacts the shoulder 26. The ridge or step on nozzle 50 seals with the shoulder 26 while its end portion extends therebeyond and a predetermined or dosed amount of adhesive or adhesive components is injected so as to provide a first adhesive fill 52 as shown diagramatically in Fig. 3. This adhesive passes along the supply passage 20 and out through the radial openings 32 and fills the space surrounding the rod 10, within the second layer or skin 42 right up to the corresponding collar 16. The manner of injection is such, of course as to avoid the possibility of the adhesive passing through the openings 34.

The adhesive used may be of any suitable adhesive such as is employed in constructional fixings, for example it may comprise an epoxy resin plus hardener composition, a polyester adhesive, a cementitious grout, or the like.

After the first adhesive fill 52 has been introduced, this adhesive is caused or allowed to set, and after the elapse of a suitable period of time the security of the adhesion of the rod 10 within the second skin or layer 42 is tested, e.g. by testing to ensure that its pull-out or bending load resistance is of at least a predetermined value. This having been established, a different nozzle illustrated diagrammatically at 54 is introduced into the wider section 22 of the supply passage 20.

This nozzle 54 is shaped to enable a second adhesive fill 56 (Figs. 5 and 6) now to be injected so as to pass out through the radial openings 34 and substantially fill the space surrounding the rod 10 within the first layer or skin 40 up to its collar 18, the ribs 1 9 on the latter again ensuring that air can be displaced from this space by the adhesive upon this second fill 56 of adhesive.

Upon the second adhesive fill 56 setting, the installation of the tie to anchor the two layers or skins 40, 42 is effectively completed and many such anchorages will be provided as may be desired in each panel 44. However, of course, further expedients may be adopted as may be desired. For instance as shown in Fig. 6, the borehole 14 may be blocked off by screwing a masking plug 58 into the open outer end of the supply passage, the plug 58 having a head large enough to overlap the end of the borehole 14. This plug may screw into a corresponding thread in the supply passage or may have a selftapping thread to bite into the walldefining such passage. Other forms of plug may be used as an alternative; for instance it may comprise a body which enters into and substantially wholly occupies that part of the boreholes 14 not occupied by the rod 10.If desired, one may provide adapters which engage into the open ends of the passages 20 at the ends 24 of the ties and enable external cladding to be fastened to the panel 44.

Figs. 7 to 9 of the accompanying drawings illustrate a modified embodiment of the constructional tie in accordance with the invention. The only difference compared to the above-described embodiment is in the form of the collars and in the provision of a further shoulder 76 in the wider section 22 of the supply passage 20. The other parts of the tie which correspond exactly to the previous embodiment are indicated by the same reference numerals as previously. The collars 66, 68 of this modified tie, instead of being provided with ribs or protrusions 1 9 have around their periphery a number of spaced-apart axially extending grooves 69, in this instance four equally spaced slots, as indicated clearly in Fig. 8.The grooves 69 permit displacement of air upon introduction of adhesive to the bores surrounding the tie, whilst the majority of the outer surface of the respective collars 66, 68 are in contact with the walls of the respective bores.

The modified tie is shown in Figs. 7 and 9 being installed in a cavity wall comprising parallel inner and outer skins 70, 71, which are then connected and held relative to one another by means of the tie. The method of installation is exactly as previously described, the collars 66, 68 being located in the respective bores 72, 73 in the skins 70, 71 immediately adjacent the intervening cavity 74 and the adhesive being injected in the previously described sequence, firstly with a nozzle 50 engaging the shoulder 26 so that a first fill is achieved in the blind bore 72 in the inner skin 70 and subsequently with a different nozzle 54 engaging the further shoulder 76 so that a second fill is separately achieved in the bore 73 in the outer skin 71.

In both methods of installation, which are substantially indentical, it is envisaged that adhesive will be supplied in dosed amounts so as to fill the bores in the respective skins as completely as possible and ensure secure setting of the tie. Supply of predetermined doses of adhesive also means that adhesive does not emerge to any great extent through the gaps or slots in the collars into the space around the central part of the tie. A nozzle suitable for such dosed supply of adhesive is shown in Fig. 10.

The invention is not confined to the precise details of the foregoing examples and variations may be made thereto. Thus, for instance the elongate element of the tie of the invention does not have to be in the form of a screw-threaded rod, and any rod-like element having an external surface formation or configuration contributing to good adhesive anchorage in a borehole can be used. Thus, the rod could have circumferential grooves or knurling or protrusions to achieve this, instead of the threading. Moreover the inner end of the rod need not be flattened, as in the described embodiments, but may be pointed or have a dove-tail profile so as to allow extra space between the rod and the surface of the base into which adhesive can spread during fixing.

In the illustrated embodiments, the locators are in the form of collars which may be rigid or, alternatively may be produced from flexible material so as to be adjustable for marginal differences in hole diameter. The form of the locators can, of course, differ from what has been shown, as also can the positions of the radial openings, and the manner in which the borehole 1 4 is finished off after the installation has been completed.

Claims (11)

1. A constructional tie comprising an elongate element having an external surface or configuration with which a good adhesive anchorage in a borehole can be achieved, a spaced-apart pair of locators on said elongate element for locating the latter in a borehole in spaced-apart constructional members or layers, an adhesive supply passage extending longitudinallly of the elongate element and consisting of a relatively wide section extending from one end thereof to a shoulder and a relatively narrower section extending from the shoulder towards the other end thereof, and respective openings from the wide section and from the narrower section of the supply passage enabling adhesive to be supplied, after insertion of the elongate element into a borehole, to the exterior of the element selectively to the one side of one of the locators and then to the other side of the other of the locators.

2. A constructional tie as claimed in claim 1 wherein the elongate element is in the form of a rod, which is axially bored to provide the supply passage and is externaliy screwthreaded to provide for good adhesive anchorage.

3. A constructional tie as claimed in claim 2 wherein the locators are in the form of collars which are internally threaded to engage with the rod.

4. A constructional tie as claimed in claim 3 wherein the collars are formed of flexible material and are provided with spaced-apart external axially-extending ribs or protrusions.

5. A constructional tie as claimed in claim 3 wherein the collars are formed of flexible material and are provided around their periphery with spaced-apart axially extending grooves.

6. A constructional tie as claimed in any preceding claim wherein a further shoulder for engagement with an adhesive supply nozzle is provided in the relatively side section of the supply passage.

7. A method of installing, in a building structure or component so as to tie together two adjacent members thereof, a constructional tie as claimed in any of claims 1 to 6, said method comprising inserting the tie, with the relatively narrower section of its supply passage innermost, into a borehole, which extends through the first of said members and into the second of said members, until the tie reaches a position wherein the locators are disposed one in each of the said members, inserting an adhesive injecting nozzle into the wider section so that it engages the shoulder between the narrower and wider sections of the supply passage, and injecting a setting adhesive through said nozzle so as to provide a first fill in the space outside the elongate element within the second of the members up to the locator disposed therein, and subsequently withdrawing the adhesive injecting nozzle and introducing further adhesive into the supply passage to provide a second fill in the space outside the elongate element within the first of the members up to the respective locator.

8. A method as claimed in claim 7 wherein the first adhesive fill is allowed or caused to set, and the security of the adhesion of the elongate element within the second member is tested prior to the introduction of the second adhesive fill.

9. A method as claimed in claim 7 or 8 wherein the first and second adhesive fills are supplied as pre-determined adhesive doses.

10. A constructional tie substantially as hereinbefore described with reference to and as illustrated in Figs. 1 to 6 or in Figs. 7 to 9 of the accompanying drawings.

11. A method of installing a constructional tie in a building structure or component so as to tie together two adjacent members thereof substantially as hereinbefore described with reference to the accompany drawings.