1 Compressible Expansion Joint Strip

This invention relates to sealing of gaps in concrete work or like material.

In the past, gaps, such as expansion gaps, in concrete 5 work have been sealed by the use of expandable sealing strips. In accordance with usual practice, the gaps are formed either by cutting away set concrete material or by use of suitably formed parts of the concrete form work which parts extend into the unset 10 concrete such that, when set, the concrete forms a groove of form complementary to that of the form work part. These methods are however somewhat unsatisfactory in that they are labour intensive and generally inconvenient. Furthermore, they do not 15 readily permit use of sealing strips and complementary grooves having downwardly divergent configurations which is desirable in the interests of retention of the strip in the gap.

According to the present invention however there is 20 provided a method of positioning an expandable sealing strip in a settable body of material comprising pressing the sealing strip into the surface of the material before it has set and allowing the material to set therearound.

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In one embodiment, the strip is reinforced by removable reinforcing means during the said pressing. The reinforcing means may, for example, comprise a- pair of opposed planar elements positioned one to either lengthwise extending side of the strip and engaged against respective opposed surfaces of the strip. Alternatively, one or more elements may be provided extending into the strip and which are subsequently withdrawn.

The invention also provides apparatus for positioning an expansible sealing strip in a settable body of material comprising means for pressing the sealing strip into the surface of the material before it has set.

The invention is further described with reference to the accompanying drawings in which:

Figures 1, 2 and 3 are fragmentary diagrammatic cross-sectional views illustrating one method in accordance with the invention;

Figures 4 and 5 are fragmentary cross-sectional diagrams showing an alternative method in accordance with the invention;

Figure 6 is a perspective view showing a reinforcing element useful in the method of Figures 4 and 5;

Figure 7 is a vertical section of apparatus for carrying out a third method in accordance with the invention;

Figures 8, 9, 10 and 11 are fragmentary cross sectional diagrams showing steps in the third method of the invention using the apparatus of figure 7;

Figure 12 is a diagram showing a preferred 5 cross-sectional form for sealing strips used in practising the invention; and

Figure 13 is a fragmentary perspective view of a reinforcing element used in the method of figures 1 to 3.

10 In figures 1 to 3, an elongate somewhat flexible sealing strip of expandable cork material, such as that marketed under the trade mark SPANDEX is shown. This material is formed by subjecting cork material to a heavy pre-compression and has the characteristic

15 that although generally dimensionally stable it will, when inserted into a gap, expand over a period of time to tightly engage and seal against the side surfaces of the gap. Strip 10 has a generally rectangular cross-sectional configuration, being of greater height

20 than it is wide. The strip 10 is shown encompassed by an elongate channel shaped stiffening element 12 best shown in figure 13. Element 12 is formed from thin sheet metal, being of inverted U-shaped form having two side flanges 14, 16 interconnected by a web

25 portion 18. The web portion 18 is disposed immediately above and in light engagement with an upper face 10a of the strip 10, whilst the flanges 14 t- and 16 are disposed to extend down and lightly engage side faces 10b, 10c of the strip 10. In order to

30 position the strip 10 within a mass of unset cementitious material, such as the unset concrete 15

shown in figure 1, the element 12, with the strip 10 retained therein, is merely advanced towards the surface 15a of the material 15 and pressed thereinto as shown in figure 2 until the element 12 and the

5 retained strip 10 are within the material 15. As shown, the strip and element may be pushed down into the material 15 until the web portion 18 of the element 12 is about level with the upper surface 15a of the material 15. After such positioning, the

10 element 12 is removed by moving it upwardly away from the material 15 leaving the sealing strip 10 in position as shown. Since the material 15 is still somewhat fluid at this stage, it will immediately flow around the strip 10 to enclose it at its side faces

15 10b, 10c and at its lower face lOd.

In figures 4 and 5, a sealing strip 20 of the aforementioned "SPANDEX" material is shown, this being also of generally rectangular cross-sectional form having two side faces 20b, 20c, a lower face 20d and 20 an upper face 20a. Face 20a has an elongate lengthwise extending slot 22 which extends from the face 20a to a location just short of the face 20d.

An elongate stiffening element 24 is shown in figure 6 as being of generally T-shaped cross-section having a

25 pair of oppositely directed and sidewardly extending flanges 26, 28 and a downwardly depending portion 30. As shown in figure 4, element 24 is engagable with strip 20, the portion 30 being neatly accommodated within the recess 22 and the flanges 26, 28 resting

30 upon the upper face 20a of the strip 20. Insertion of the strip 20 into ^' the unset concrete material 15 is effected in a similar manner to that described in

described in relation to figures 1 to 3. That is to say, the assembled element 24 and strip 20 are advanced towards the surface 15a of the unset concrete material 15 and pressed thereinto, face 20d first, as shown in figure 4. Pressing is continued until the face 20a is generally aligned with the upper surface 15a of the concrete material 15. Thence, as shown in figure 5, the element 24 is removed by upward movement thereof so as to release it from the strip 20. Under this condition, since the concrete material 15 is, as described, unset and still to some extent fluid, the concrete material bears against the opposed faces 20b and 20c. The side-to-side extent of the recess 22 is such that there is some degree of resilience as between opposed side portions of the strip 20 to either side of the slot and the pressure force exerted by the unset concrete material against the faces 20b, 20c is such as to cause inward deformation of these portions towards each other until upper ends thereof meet as shown in figure 20. In this case, the recess 22 is, in effect, substantially closed at face 20a, the strip 20 then assuming the somewhat trapezodial configuration shown at which the side-to-side dimension is greater at the base than at the upper end thereof. Thus, when the material 15 is set, the strip 20 is accommodated in a complementary groove of the material 15 which groove is also of somewhat trapezodial form having an upper end rather narrower than the lower end, thus tending to resist outward movement of the strip 20 therefrom.

Figure 7 shows an apparatus 50 in the form of a carriage 52 having wheels 54 which engage and run on rails 56 one to either side of a slab of unset

concrete 58 retained between opposed formwork elements 60. Thus, the carriage 52 is movable lengthwise along both the formwork elements 60 and the slab of unset concrete 58. The apparatus 50 is designed so that it is capable of positioning a number of strips of sealing material such as the aforementioned SPANDEX at spaced locations along the length of the formwork 60 so as to extend from side-to-side of the unset concrete 58. Thus, the carriage 52 has a first sub-carriage 62 which is mounted for vertical movement from a cross bar 57 at an upper location on the carriage 52. This mounting is effected by means of extensible rams 64 interconnecting the sub-carriage 62 and the cross bar 57. Sub-carriage 62 is of channel-shaped form having a pair of opposed side flanges 62a, 62b and a lower web portion 62c -interconnecting flanges 62a, 62b. Sub-carriage 62 extends from side-to-side of the carriage 52.

A second sub-carriage 66 is provided mounted on and within sub-carriage 62 for vertical movement relative to sub-carriage 62. Sub-carriage 66 is also of generally channel-shaped configuration extending lengthwise of sub-carriage 62, that is to say from side-to-side of the carriage 52. Sub-carriage 66 has a pair of opposed flanges 66a, 66b interconnected by a lower web 66c. Sub-carriage 66 is mounted to sub-carriage 62 by means of two hydraulic rams 70 operable to effect the aforedescribed relative vertical movement between sub-carriage 62 and sub-carriage 66.

Sub-carriage 66 has a series of downwardly extending spikes 72 arrayed along the length of the sub-carriage and extending from lower web 66c. The web portion 62c of sub-carriage 62 is provided with a series of apertures 76 therethrough and the sub-carriage 66 is so movable relative to the sub-carriage 62 that it can be moved to a relatively upwardly spaced disposition illustrated generally at figure 7, at which the spikes 72 whilst being aligned with respective ones of the apertures 76 do not extend therebelow or at least only extend slightly therebelow. From that position, the sub-carriage 66 is movable by manipulation of rams 70 relatively downwardly with respect to sub-carriage 62 to a position at which the spikes extend some distance below the underside of the flange portion 62c of sub-carriage 62.

Referring now to figures 8 and 9, the operation of the apparatus 50 to position a rectangularly cross-sectioned strip 80 of SPANDEX material in the unset concrete 58 is now described. Firstly, with the rams 64 moved upwardly to a position sufficient to well clear the sub-carriage 62 from the upper surface 58a of the unset concrete 58, and with the sub-carriage 66 moved upwardly to withdraw the spikes 72 through the apertures 76, the strip 80 is positioned along the underside of the web portion 62c of sub-carriage 62. Whilst holding the strip 80 against downward movement (by means not shown) the rams 70 are then actuated to move sub-carriage 66 vertically downwardly so that the spikes 72 pass through the apertures 76 and thence pass into the strip 80 through face 80a, as shown in Figure 8. Then, when the sub-carriage 66 is moved downwardly

sufficiently to bring the lower ends of the spikes well down within the body of the strip 80, the two sub-carriages 62 and 66 are together moved downwardly by actuation of the rams 64 to press the strip 80 into the unset concrete 58, with the lower face 80c first passing through the upper surface 58a of the concrete 58, as shown in figure 9. When the strip has been ■ moved downwardly to a sufficient extent, such as to bring the upper face 80a roughly into alignment with the surface 58a of the concrete 58, the rams 64 may be together actuated to move the two sub-carriages 62, 66 upwardly to clear the spikes 72 from the strip 80 thus leaving the strip ±n situ.

The described constructions have been advanced merely by way of explanation. It will be understood that in each case where withdrawal of a reinforcing element such as the element 12, 24 or sub-carriage 66 and its spikes 72 is to be effected, it may be necessary to provide specific means for holding the strip such as the strips 10, 20 and 80 in position during such withdrawal. This may be effected in the case of the method shown in figures 1 to 3 by providing apertures in the web portion 18 of the element 12 and to permit pressing against the upper face 10a of the strip 10 by means of downwardly depending elements which extend through those apertures. In the case of the method described in figures 4 and 5, a similar procedure may be carried out by use of elements extending downwardly through apertures in the flanges 26, 28 to bear against the upper face 20a of the strip. In the case of the method described in relation to figures 8 and 9, the withdrawal may be effected by first leaving the sub-carriage 62 in the position assumed at the

lowermost extent of its downward movement for insertion of the strip 80 into the concrete 58. Usually this will be a position at which the underside of the flange portion 62c is roughly aligned with the upper surface 58a of the concrete 58. Then, as illustrated in figures 10 and 11, the sub-carriage 66 can be moved vertically upwardly without movement of sub-carriage 62, such as by actuation of rams 70,so that the spikes 72 are withdrawn through the apertures 76 to a sufficient extent to clear them from the strip 80. Thereafter, the aforementioned upward lifting of the sub-carriages 62 and 66 together by actuation of rams 64 may occur.

Whilst, in the described arrangements, the strips 10, 20 and 80 are described as being of generally rectangular cross-sectional configuration, it may be preferable in some circumstances to use strips of differing configuration. For example, in figure 12 a strip 90 is shown of generally rectangular form but having opposed side faces 90a, 90b which are not parallel, these exhibiting a slight taper one towards the other in the direction from a lower end thereof towards an upper face 90c thereof. That is to say, there is a slight angle, indicated as "Θ" in figure 12, between these two faces. At the lower end, the strip 90 also has a somewhat rounded lower end portion 90d in order to facilitate penetration into the unset material.

The apparatus of the invention has been most specifically described in relation to the embodiment of figure 7. It will be appreciated that the apparatus of figure 7 may be readily modified so as to

effect insertion of sealing strips by any other of the described methods such as those shown in figures 1 to 3 and in figures 4 and 5.

It will be appreciated that in each described method, the reinforcing of the sealing strip provided by the elements 12 and 24 or by the spikes 72 and sub- carriages 62, 66 enables the somewhat flexible strips to be maintained in a desired configuration, such as a linear configuration, during insertion, whereas otherwise the strip may not adopt such desired configuration and may for example present an untidy appearance. Again, the elements 12 and 20 and the spikes 72 and sub-carriages 62, 66 facilitate insertion of the strips in a desired orientation such as with the side surfaces truely aligned in vertical planes. Of course, for the elements 12, 24 and the sub-carriages 62, 66, the strips may be conformed to desired configurations such as sinuous or other curved forms, even of complex form, whereas in the prior methods described herein such configuration can only be achieved with difficulty.

Usually, as described, the reinforcing means employed, be it the elements 12 or 24 described or the sub-carriages 62, 66 together with spikes 72, are removed from engagement with the sealing strip. In particular such removal may be effected before setting of the concrete therearound. However, the reinforcing means may be left permanently in the position engaged until setting (particularly for example in the case of the element 24) or may be removed after setting of the concrete.

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