TITLE: ARMOUR JOINT ASSEMBLY SUPPORT APPARATUS

FIELD

This invention relates to the field of construction with concrete, with particular application to placement of joint assemblies at the adjoining edges of large poured-in-place concrete slabs.

BACKGROUND

Poured concrete contracts significantly during curing and, once it is set hard, continues to expand and contract with temperature changes. To prevent random cracking or spallation around edges where impacts may be applied, large surfaces such as floors or roadways are commonly divided into smaller concrete slabs, often with armour joints anchored into them along expansion joints. The armour joints are typically paired steel plates, anchored into the mass of the adjoining slab, that circumscribe the length and width of the concrete slabs and provide a hard-wearing steel lip at the edge of each slab. When the concrete contracts during curing, the paired plates move apart to leave a clean gap between them, and thereafter as the concrete moves with temperature change, the paired plates move further apart or come together. The maximum width or length of any one slab that is immune from contraction causing undesired and unpredictable cracking depends to some extent on whether sliding against the underlying substrate is possible (a subject which is outside the scope of this invention), and also on whether there is any gripping or other interaction between one slab and the next across the deliberately inserted crack or joint. Hence proper positioning is desirable in order to minimise the number of expansion joints used in a given floor. The armour joints need to be kept firmly in position during assembly and during pouring, of the concrete slabs they circumscribe, with the paired plates of each joint lying flush with each other and with the slab surface. However because of the amount of contraction during the curing process, there can be significant relative movement between the slabs as they cure, and the armour joint plates need to move with the slab they are anchored into. Movement in the plane of the length and width of the concrete slab is necessary, as the slabs contract away from each other and (particularly if one slab is curing next to another which is already dry) if one shrinks relative to the other. However, movement between the plates in the direction of the thickness of the slab must be minimised, so that the face defined by its length and width remains in the same

plane. Most typically the object of this is to keep floors level, without either plate sitting or moving higher or lower than the other, which would create an inconvenient and possibly dangerous step in the floor. The joint may also be covered with a horizontal metal cover strip fastened into one slab and in sliding contact with a seat on the lip of the other, to span over the joint. As the slabs expand or contract, the strip slides horizontally with the slab it is fixed onto, to extend further or less far over the lip of the other slab.

To achieve this purpose, adjoining slabs are linked with load-transfer dowels comprising rods or plates or other strong linking means traversing the joint, which are seated on one or both sides in a slot allowing some freedom of movement in a horizontal plane, but not vertically. These dowels should be oriented parallel to the slab surface since most of the movement of one slab relative to the other during expansion or contraction is parallel to the plane of the slabs, i.e. horizontal in the case of a concrete floor, It is important that the structures of the armour joint are accurately aligned with the plane of the slabs. If the length axes of the load-transfer dowels are even slightly tilted out of the horizontal plane, they will not slide in their slots when the slabs expand or contract but tend to raise or depress the slab edges, resulting in stress on the slab edges and possible fracturing anjαvhere within a slab. Similarly, if the metal cover strip over the joint (Fig 3) is tilted, as a slab expands or contracts the strip will tend to lift away from or bear against the seat on the lip of the other slab, rather than simply sliding across it.

PROBLEM TO BE SOLVED

There is therefore a need for means by which the position and tilt of the components of an armour joint can be finely adjusted before poured concrete has set, to ensure that all parts of the armour joint assembly lie in the correct plane within the perimeters of the poured-in-place slabs.

OBJECT

It is an object of this invention to provide an improved armour joint assembly, or at least to provide the public with a useful choice.

STATEMENT OF INVENTION

In a first broad aspect the invention provides an armour joint assembly support apparatus for placing an embeddable armour joint assembly intended for use in within an elongated expansion gap between adjacent slabs of concrete, each of which slabs shall when made have a surface lying in a common surface plane, and sides, and a depth in a direction orthogonal to the surface; the armour joint assembly including two parallel strips elongated along an axis, inter-slab dividing means, and a plurality of intra-slab anchor means along each strip, the joint assembly also including a plurality of transverse linking dowels each of which shall be slidably embedded in one and embedded in another adjoining slabs, there serving to minimise changes in the relative heights of the respective slab surfaces yet allowing the slabs to expand and contract; each dowel having a length axis; wherein the armour joint assembly support apparatus includes (a) footing means adapted to be reversibly anchored to a substrate; the substrate having a plane of orientation, (b) connection means adapted to be reversibly attached to the armour joint assembly, and (c) adjustable holding means capable of locating the connection means relative to the footing means including at least two modes of adjustment so that, when in use, the adjustable apparatus permits the armour joint assembly to be held in a correct position and orientation with respect to the surface of the slabs while concrete is poured about the armour joint assembly and until the concrete has become solid.

Optionally, the apparatus can adjust and hold the tilt of the armour joint assembly, only.

, In a first related aspect, the apparatus is located on one side only of the armour joint assembly so that the concrete may be poured over the other side of the assembly yet the adjustable holding means remains accessible and capable of further adjustment until the concrete has set, whereupon the support apparatus may be taken up and used again.

Preferably the height of the apparatus above the substrate is less than the intended surface of the slabs of concrete.

Optionally the apparatus is capable of being left in place, so that concrete may be poured over both sides of the armour joint at the same time, covering the support apparatus.

Preferably a plurality of the apparatus is used along a length of an armour joint assembly, spaced apart at typically 1 metre intervals.

In a second related aspect, the mechanism of the support means incorporates at least one

85 adjustable holding means comprising as a first component a rotatably restrained, rotatable threaded rod, and a second component including a threaded nut or threaded aperture capable of being advanced or retracted along the length of the first component if relative rotation between first and second components is caused; each adjustable holding means held in place between the footing means and the connection means so as to be capable, if the first component is rotated, of

90 driving the footing means and the connection means together or apart along a sliding or pivoted path.

In a first alternative aspect, the apparatus provides adjustable holding means for adjustment of the height of the armour joint assembly relative to the surface plane in order to cause the armour joint assembly to lie on or below the surface plane, and means for rotation of the armour joint 95 assembly around the axis of the assembly in order to cause the length axis of the horizontal dowel to be aligned perpendicular to the elongated expansion gap, so that after the concrete has set the armour joint assembly remains flush and allows the slabs to repeatedly expand and contract while the surfaces of each adjacent slab of concrete are held at the surface plane.

In a second alternative aspect, the apparatus provides adjustable holding means capable of

100 adjustment of the straightness of the armour joint along the axis of the joint assembly (along the expansion gap), and means for rotation of the armour joint assembly around the axis of the assembly in order to cause the length axis of the horizontal dowel to be aligned perpendicular to the elongated expansion gap (parallel to the plane of the surface of the concrete slabs), so that after the concrete has set the armour joint assembly remains flush with the surface plane and

105 allows the slabs to repeatedly expand and contract while the surfaces of each adjacent slab of concrete are held at a substantially identical height.

In a third alternative aspect, the armour joint support apparatus provides adjustable holding means for adjustment perpendicular to a surface plane of the adjacent slabs of concrete, and means for adjustment parallel to a surface plane of the adjacent slabs of concrete, in order to

110 cause the armour joint apparatus to lie flush with the intended surface of the concrete slabs, and means for rotation (tilting) of the armour joint assembly around the axis of the assembly in order to cause the length axis of the horizontal dowel to become parallel with the plane of the concrete slabs, so that after the concrete has set the armour joint assembly lies flush with an outer surface of the concrete and allows the slabs to repeatedly expand and contract while the surfaces of each

115 adjacent slab of concrete are held at a substantially identical height.

In another aspect the invention provides an armour joint support apparatus for adjoining slabs of a settable fluid material such as concrete, including paired and aligned armouring plates, one to be anchored in each slab in use, and a support structure holding the joint assembly in a chosen position and orientation while concrete is poured alongside the assembly; wherein the support 120 apparatus includes footings adapted for anchoring to a substrate, each connected to an armouring plate by at least one spaced-apart adjustable holding means, at least one adjustable holding means being of adjustable length, such that by adjustment of the length of at least one adjustable holding means the orientation of the joint assembly relative to the support apparatus can be adjusted.

Alternatively the adjustable holding means are spaced apart in a direction orthogonal to the 125 direction of depth of the slabs such that by adjustment of the length of at least one adjustable holding means the tilt of the joint assembly can be adjusted relative to the support apparatus and relative to the depth dimension of the slabs.

Preferably at least one adjustable holding means comprises a rotatably mounted threaded rod extending from the support apparatus to the joint assembly, passing through a threaded aperture 130 in either or both the support apparatus and a part of the joint assembly, such that rotation of the rod drives that part of the joint assembly away from or towards the support apparatus in a lengthwise direction.

Preferably both adjustable holding means of the pair comprise a rotatably mounted threaded rod extending from the support apparatus to the joint assembly, passing through a threaded aperture 135 in either or both the support structure and a part of the joint assembly, such that rotation of the rod drives that part of the joint assembly away from or towards the support apparatus.

Preferably the adjustable holding means extends in a generally lengthwise direction, such that

rotation of a rod drives that part of the joint assembly towards or away from the support apparatus in a lengthwise direction.

140 Alternatively the adjustable holding means extends in a depthwise direction, such that rotation of a rod drives that part of the joint assembly towards or away from the support apparatus in a depthwise direction.

Preferably the armour joint assembly further includes a subframe connected to one armouring plate, including a face plate extending from the armouring plate to the base of the slab in use, 145 wherein tilt of both the subframe and of the armouring plate together can be adjusted relative to the support apparatus by adjustment of the length of at least one adjustable holding means, such that the face plate can be oriented in a depthwise direction relative to the slabs.

Preferably the armour joint assembly further includes a series of load transfer dowels connected to the subframe, wherein the tilt of the load transfer dowels, the subframe, and armouring plate 150 together can be adjusted relative to the support apparatus by adjustment of the length of at least one adjustable holding means, such that the load transfer dowels can be aligned with a lengthwise dimension of the slabs.

PREFERRED EMBODIMENT

The description of the invention to be provided herein is given purely by way of example and is 155 not to be taken in any way as limiting the scope or extent of the invention. Throughout this specification unless the text requires otherwise, the word "comprise" and variations such as "comprising" or "comprises" will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

160 DRAWINGS

Fig 1 : shows a first armour joint assembly and support apparatus of the invention in side view.

Fig 2: shows the assembly of Figure 1 with the tilt adjusted.

Fig 3: shows the support apparatus of Figure 1 in association with a second armour joint assembly.

165 Fig 4: shows a third armour joint assembly and support apparatus of the invention in side view.

Fig 5: shows the support apparatus of Figure 4 in plan view.

Fig 6: shows the support apparatus of Figure 4 in side view, with the tilt adjusted.

Fig 7 shows another version of support apparatus.

For convenience, the following description is made for convenience with reference to pouring 170 concrete floor slabs, wherein the width and breadth of the surface of the slab, and the length of the armour joint plates are horizontal, and the depth or thickness of the slab is vertical. It will be appreciated that if the invention were to be applied to a poured concrete wall slab or other non- horizontal construction, the orientation of the various components would be changed accordingly.

175 EXAMPLE 1

In a preferred form as shown in Figs 1 to 6, the invention provides a support apparatus for an armour joint assembly 10 for protecting the adjoining edges of two adjacent concrete slabs. The support apparatus may be temporary and reusable, or, if it becomes buried, (such as if both sides of the armour joint are poured together, it is permanent. These drawings show a far side of the

180 concrete floor 14 as already poured, in order to show that the apparatus must withstand a certain amount of force from the initally wet concrete. The armour joint assembly is comprised of two edging strips 11 and 12, one of which incorporates vertical formwork 16 for containing and dividing the poured concrete of the slabs with a metal sheet serving as inter-slab dividing means, and horizontal load transfer dowels 17 to link the two slabs and distribute any load bearing on

1S5 one slab through to the adjacent slab. There is rather little tolerance for non-horizontal orientation of the load transfer dowels, since movement of tilted dowels would either meet with

excessive friction or would cause slab edges to change height respective to each other, perhaps putting concrete under tension and causing fractures.

As shown in Figure 1, a first embodiment of the joint assembly 10 is comprised of two elongate

190 horizontal edging plates 11 and 12, one anchored by anchor 15 (out of the plane of these sections) at the upper rim of each of two adjoining concrete slabs or intended slabs in use, and temporarily joined by a series of bolts 13 with strippable nylon nuts or the like. The upper surfaces of the two strips 11, 12 are aligned, and lie in the same plane as the upper surface 14 of the poured concrete slab(s), to provide a smooth, continuous floor plane without steps. The strip

195 11 comprises a relatively simple protective metaj edging for the upper rim of the concrete slab, with a series of anchors 15 projecting from it to be embedded in the concrete slab in use. The strip 12 is fixed to a subframe which further includes a vertical form or wall 16 and transverse dowels 17 all rigidly interconnected with a bracing plate 19 behind the wall 16. The subframe is preferably welded together, and forms a rigid structure by which the arrangement and orientation

200 of the various components relative to each other is fixed.

The load transfer dowels 17 preferably comprise flat metal plates projecting through the wall 16, to engage with both concrete slabs in use. The portion of the dowels projecting beyond the wall 16 may be sheathed in a flexible or resilient sleeve 18, to allow slight transverse movement of one slab relative to the other. These dowels are intended to prevent or at least minimise relative 205 vertical movement of slabs and their correct alignment is desirable.

The joint assembly 10 is anchored in place before the concrete has been poured, to act as formwork defining the edges of the slabs and the divisions or breaks between them. The joint assembly is fixed in place with a support structure 20 anchored into the ground or other substrate.

The support apparatus 20 is comprised of one or a series of footings positioned at intervals along 210 the length of the joint assembly, preferably always on one side of the assembly. Each footing has a base plate 21, which is adapted to be temporarily anchored into the substrate with a pin or bolt 22. A pillar 23 is fixed on the base plate, and a bracket 24 is mounted on the pillar 23 with a screw-drive mechanism 25 including nut 25, threaded bolt 25A which bears on plate 23A (part of the pillar 23) by which the bracket 24 can be moved up or down the pillar, to adjust the height of

215 the joint assembly 10 above the base plate 21 in use.

The joint assembly 10 is temporarily mounted on the bracket 24 with a pair of bolts 26 and 27. The bolts are positioned vertically one above the other, with a space between them. The bolts 26 and 27 are rotatably fastened to the bracket 24, with at least the upper bolt 26 being rotatably fastened in a vertical slot in the bracket 24, such that it can be moved up or down on the bracket 220 to suit different slab thicknesses or different types of joint assembly 10. While the bolts are able to rotate and (in the case of the upper bolt 26) be moved up or down on the bracket 24, they are prevented from moving horizontally through the bracket 24, by the head of the bolt on one side and a welded washer or stopper 28 on the other.

The bolts 26 and 27 are engaged with coresponding nuts or threaded apertures 29 in the bracing 225 plate 19 of the joint assembly 10. By rotating the bolt, the bracing plate 19 and the entire assembly 10 which is fixedly connected to it can be screw-driven towards or away from the bracket 24 at that point.

The substrate onto which the support apparatus is anchored may be inconsistent or imperfectly levelled, and the support structure 20 may accordingly be anchored somewhat off level, i.e., with

230 the base plate not exactly horizontal and the pillar 23 and bracket 24 not exactly vertical. It is important however for the functioning of the joint assembly that the load transfer dowels 17 be exactly in alignment with the expanse of the slab, i.e., horizontal in the case of a floor slab. Similarly, with a particular "covered" kind of armoured joint assembly as shown in Figure 3 which includes overlapped edging strips 11 and 12, it is important that the plates be aligned with

235 the surface of the slab so that lengthwise movementof the slab causes the plates to slide across each other rather than pulling apart or pressing together, and no deep gap appears.

As shown in Figures 2 and 3, a tilt in the support apparatus 20 as secured to the substrate can be compensated by means of use of the adjustable bolts 26 and 27. As shown in Figure 2, if the support structure has a backward lean, the upper bolt 26 can be turned to drive the upper threaded 240 aperture 29 further from the bracket 24. This pushes the whole upper part of the joint assembly 10 away from the bracket 24, tilting it to the correct orientation. Similarly as shown in Figure 3, a forward tilt of the support structure 20 can be compenstated for by turning the upper bolt in the

opposite direction to pull the upper part of the joint assembly closer towards the bracket 24, and/or by turning the lower bolt 27 to push the lower part of the joint assembly 10 further away.

EXAMPLE 2

As shown in Figures 4 to 6, the tilt adjustment mechanism of the support apparatus could be provided as a generally horizontal arrangement 30 rather than the generally vertical arrangement 20 shown in Figures 1 to 3. This version has an advantage of less height so that there is no impediment to movement of concrete finishing machinery for example over slab 14. Indeed, the support apparatus could be sacrificed if for example there were for example time pressures in force. In this example, the vertical bracing plate 19 comprises a relatively simple plate supporting the edging strips 11 and 12 for example by means of one or more of the bolts 13, which are fastened through it as well as through the edging strips 11 and 12. A small L-section bracket 31 is welded to the bracing plate 19, and is in rum fastened with bolts 32 to a horizontal channel member 33.

The horizontal channel member 33 has a generally inverted-U section and sits over a horizontal footing bracket 34. The footing bracket 34 may be anchored directly into the substrate with a pin or bolt 22, or more preferably is connected to such an anchoring pin 22 with a pair of L-section brackets 35, joined with a horizontal adjustment bolt 36. This allows small adjustments to be made in the horizontal position of the support apparatus 30 and hence the edging strips 11 and 12, relative to the anchoring pin 22.

The horizontal channel member 33 is fastened to the footing bracket 34 with a pair of bolts 37 and 38. The bolts are positioned with a horizontal space between them, and are rotatably fastened to the channel member 33. While the bolts are able to rotate they are prevented from moving vertically through the channel member 33, by the head of the bolt above and a welded-in-place washer or stopper below.

The bolts 37 and 38 are engaged with corresponding welded nuts or threaded apertures 39 in the footing bracket 34. By rotating a bolt, the horizontal channel member 33 and the entire support apparatus 10 which is fixedly connected to it can be screw-driven towards or away from the

270 footing bracket 34 at that point, tilting it as shown in Figure 6. By this means the channel member 33 can be made horizontal, the bracing plate 19 made vertical, and accordingly the edging strips 11 and 12 and their connecting bolts 13 made horizontal, even if the footing bracket is not properly horizontal because of irregularities in the substrate or inaccurate placement. Nuts 39 preferably include a relatively short threaded section, in order to be tolerant of some tilt of the

275 bolt 37 or 38. Also, the inventor prefers to use compressible washers between the heads of the bolts 37 and 38 and channel 33 and/or the welded washers or stoppers of bolts 37 and 38 and channel 33. A special thread, with a deeper profile than the usual metric thread, might be used.

It will be appreciated that adjusting both bolts 37 and 38 together will allow the height of the 280 joint assembly above the footing to be adjusted, regardless of whether or not the tilt is also adjusted.

EXAMPLE 3

As shown in Figure 7, there are other ways to interconnect sliding and pivoting members within a support apparatus in order to hold an armour joint at desired height and tilt and straightness. This

285 earliest Example appears to be less useful than the previously described Examples because it lacks means for advancement or retraction of an adjoining portion of a length of armour joint, which may be useful after a slant adjustment has been made or if the line is not straight. Also, this version of the support apparatus is usually higher than the intended slab surface height (as 11). The components of Example 3 are identified as follows: a base plate 21 is placed on, and

290 anchored to a substrate below. A lifting pillar 23 is pivotally mounted by pivot 21 A on to the base plate. One side 12 of an armour joint 11 and 12 is supported off a collar 24 over the lifting pillar by plate 31. The other side of the armour joint is, as is conventional, bolted to this side using nylon nuts or similar so that the forces of curing concrete will in due course free the two sides. The lifting pillar top has a sideways extended plate 23 A, against the underside ^" of which

295 the head 25A of a lifting bolt is welded. Height is varied by turning either nut 25B of nut 25C against the plate 24A which is extended from the collar 24. The slope of the armour joint, relative to a substrate beneath, may be varied by ricking pillar 23 on pivot 21A. A second pivot point 23 A near the top of pillar 23 is tied by means of a variable-length strut 40 and then through

pivot 45 to an angled bracket 41 on base plate 21. A threaded stud 42 is welded into one end of 300 strut 40. Two nuts, 43 and 44, may be turned together so as to advance or retract along stud 42 and thereby, by bearing against bracket 41, to force the upper end of the strut to cause the armour joint assembly to rotate about an axis set by pivot point 2 IA. Those nuts may be tightened against each other before the concrete is poured to the right side of the armour joint, thereupon burying anchor(s) 15.

305 As to a method of use, in all Examples the support apparatus is used to hold the armour joint

. apparatus itself off the substrate. An initial approximate process of placement of the armour joint apparatus itself along the line of an armour joint and supporting a length of armour joint is followed by levelling using taut strings or optical beams (for example) as the determinant of position (height and optionally straightness), and tilt adjustment using optical beams or bubble

310 levels (for example) as the determinant of slope relative to a surface of the intended slab or slabs. An operator would use an open-ended spanner to engage the screwed rods or nuts in order to make the necessary adjustments, check the indicators, trim the adjustments, and so on until a specified tolerance or precision of orientation is provided. If the pouring process is suspected of having disturbed the positioning, the adjustment of the apparatus may be checked and re-adjusted

315 against the wet concrete, hi all cases, once the concrete on the poured side has hardened sufficiently, the apparatus of this invention is unbolted from the anchored joints, separated from the substrate, and removed for re-use along another armoured joint.

VARIATIONS

It will be appreciated that a wide variety of alterations could be made to the armour joint 320 assembly support apparatus as described above, within the general spirit and scope of the invention. For instance, rotatable threaded rods and nuts are described in these Examples. Other adjustment mechanisms not using threaded rods and nuts may be substituted.

The apparatus itself can be varied in any of its dimensions to suit a particular application. The overall height of the bracket 24 is preferably about 175 mm, with the upper bolt 26 being

325 movable up or down within a slot about 100 mm in length, to allow for use with a vertical spacing between the threaded apertures on the joint assembly of anywhere from perhaps 50 mm

to 150 mm. This would allow use of the support apparatus on poured slabs of different typical thickness of up to perhaps 200 mm, and also allow use with a variety of different joint assemblies having different edging arrangements and/or different arrangements of load-transfer dowels.. 330 However, modified support apparatus could be made to suit use with slabs of a different thickness.

The adjustment bolts 26 and 27 might take a variety of different specific forms. In particular, the assembly could employ one adjustment bolt at the top together with a fixed bolt or a stationary pivot or hinge point at the bottom ^' , such that all adjustment is done by the rotation one way or the 335 other of one bolt only. While it is currently preferred for each part of the adjustable holding means to be arranged one above the other, it will be appreciated that they might alternatively be arranged in a different configuration such as, for example, two spaced-apart adjustable holding means at the bottom of the bracket and a single adjustable holding means at the top, giving a triangular arrangement.

340 The footings described above would typically be unbolted (by undoing the bolts 26 and 27) and removed after a first slab of concrete had set behind the plate 16, so that the whole support apparatus 20 could be reused. The joint assembly 10 would of course remain in place and be embedded between the two slabs in use. However, a 'single-use' support apparatus could be provided within the scope of this invention, to be covered and embedded in the poured slab along

345 with the joint assembly 10. This would allow use in situations where it is desirable to pour concrete on both sides of the joint assembly at the same time, such as for speedy erections.

Finally, it will be understood that the scope of this invention as described by way of example and/or illustrated herein is not limited to the specified embodiments. Where in the foregoing description, reference has been made to specific components or integers of the invention having 350 known equivalents, then such equivalents are included as if individually set forth. Those of skill will appreciate that various modifications, additions, known equivalents, and substitutions are possible without departing from the scope and spirit of the invention as set forth in the following claims.