AU657707B2

AU657707B2 - Continuity strip for reinforced concrete

Info

Publication number: AU657707B2
Application number: AU86992/91A
Authority: AU
Inventors: Alan Lazrus
Original assignee: Boral Building Services Pty Ltd
Current assignee: Acrow Formwork and Scaffolding Pty Ltd
Priority date: 1990-11-02
Filing date: 1991-11-01
Publication date: 1995-03-23
Anticipated expiration: 2011-11-01
Also published as: AU8699291A

Description

657 77 1- AUSTRALIA 4 14x Patents Act 1990 -0 1313 8op-AL eu 1LJZ(rO -GiR~J\C-E' WTED TGB* CONSTRUCTON" PRODUC-T T 1 TY LIMITE 00 Q a 0 0000 00 00 00 0 V 0 0U 00

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT 0 Invention Title: 000- Go 0 0 00 aContinuity Strip for Reinforced Concrete 0 too, oc 0 0 000t00 0 The following statement is a full description of this invention including the best method of performing it known to us:d -i P- 2 This invention relates to continuity strips which are used to position parts of reinforcing rods in a first concrete pour, and after the first pour has set, to allow removal of the continuity strip and the straightening of the remaining part of the reinforcing rods so as to position them in a second concrete pour. Thus the reinforcing rods continue across the interface of the two concrete pours.

It is known to produce such continuity strips using a generally box structure comprising a moulded plastics open faced case and a steel plate sheet closing the open face.

Conventional. steel reinforcing rods are bent to a U-shape, and then bent such that the arms of the U sit within the oo interior of the box and the base of the U protrudes out o* o15 through slots in the steel plate. The slots are then 0°o a sealed off between the plate and the reinforcing rods by oo o moulded plastic plugs.

00 It is also known to produce a continuity strip in o00O which the reinforcing rods are bent in a similar manner to o 00 that described above, and then the arms are encased within a foamed plastics material such as polyurethane.

A further known construction for a continuity strip 000.: includes a rectangular sectioned folded sheet steel box o 0 with its two otherwise open ends sealed with wooden inserts. Holes are punched at intervals along one face of S the box and the bent reinforcing rods are inserted through 0 I those holes.

Qoooho While each of the above described continuity strips work satisfactorily the present invention provides what is o0.000 at least a useful alternative.

In essence, the invention provides a continuity strip in which the face through which the reinforcing rods are inserted comprises a number of separable plates, each plate running between adjacent reinforcing rods so that on removal of the continuity strip, the plates may also be c 3 removed.

Accordingly, in one embodiment, the present invention may be said to consist in a continuity strip box structure comprising: an elongate hollow case section having an open elongate face; plates closing the open face so as to substantially entirely seal the case against entry of cement mix and the like, the plates being removable from the case section and each being separable from adjacent plates at separation lines; and oslots in the plates at the separation lines, each sized to closely fit about a diameter of a reinforcing Oo o element of predetermined dimension.

Preferably, two Opposite parallel edges of the open ow- face include a sliding sealing structure cooperative with °on two opposite parallel edges of the plates so as to locate and seal the plates relative to the case.

Preferably each plate includes a pair of the slots on each of two opposite ends, the ends and pairs of slots of o *0 °adjacent plates overlapping.

9Preferably the box structure comprises part of a continuity strip which further includes a plurality of reinforcing elements staggered along the box, each element residing partly internally of the box, partly externally of the box and passing through a pair of overlapping slots, the adjacent plates including the overlapping slots being positioned one toward the other so as to reduce the dimension of the overlapping E 30 slot to approximately the diameter of the reinforcing element so as to seal the box about the element against the ingress of cement mix.

Preferably the reinforcing elements are steel rods.

The rods may be shaped according to the specification of any particular construction job. They may be, for i Y r ;-L -4example, straight or bent into various configurations such as elbows, or "Us".

The box may be rectarngular in cross-section having wide and narrow sides, the open face being optionally in one of the wide sides or one of the narrow sides according to design requirements. In another alternative the box may be a parallelopiped cross-section, the open face being a shorter one of the parallel sides.

In a further broad form, the invention provides a method of using a continuity strip being as described above, the method comprising: fixing the strip relative to formwork so that parts o of the reinforcing elements external of the box reside in oep 0 a volume to be concreted and a rear face of the box 15 opposite the plates is clear of the the volume to be .oo concreted, c pouring cement mix into the formwork and allowing it 0 00 to set, and removing the case section then removing each of the oo: 20 plates so as to leave only the protruding arms of the ~e o oreinforcing elements 0 0By way of example only, preferred embodiments of the invention will now be described with reference to the .oo. accompanying drawings in which: 0000 25 Fig. 1 is a cross-sectional view of a first embodiment of the invention; Fig. 2 is a cross-sectional view of a further embodiment of the invention; Fig. 3 is a perspective view of the continuity strip shown in fig. 1; Fig. 4 is a perspective view of one end of a further embodiment of the invention; Fig. 5 is an exploded perspective view of one end of a further embodiment of the invention.

Figs. 1 and 2 show the end profiles of two continuity II-- Iy__i_ .llrr i IL 5 00 00 0 0 0 0 00 a aJ oC 1 C'C1 0 0 0 0 o 00 a 0 QO 0 00 0 o O 0 0 strips. In fig. 1 the continuity strip includes a generally rectangular cross-sectioned box 1 made from pressed sheets galvanised steel. One of the long faces of the box 1 is an open face 2 which extends between two opposite slots 3 which are formed during the bending process. The slots 3 are sized and positioned to closely receive in a sliding fit a number of plates 4 which are positioned adjacent one another going into the page so as to close off the open face 2. The fit between each plate 4 within the slots 3 is so close as to prevent the ingress of concrete mix during use of the continuity strip. Although not shown, the open face 2 can equally well be formed in one of the short side faces of the box 1.

A number of steel reinforcing rods 5, positioned one behind the other going into the page of the drawing, are compound bent to form a generally U-shaped end profile, and L-shaped side profile (fig. la) with the free arms 6 extending longitudinally of the case 1, that is perpendicularly into or out of the page in the drawing.

While this is a common configuration the rods 5 may be bent to any requirement.

Upon assembly the reinforcing rods 5 are positioned with their arms 6 positioned internally of the case i, shown in dotted outline as 6a, the arms passing through slots 7 within the plates 4, and leaving the top U-section of the rods 5 exposed externally of the case 1. The slots 7 of each plate 4 overlap slots 7 of an adjacent plate 4a, as shown in fig. 3. The adjacent plates 4, 4a, after assembly of the continuity strip, overlap one another at a separation line 8. Thus the overlapping slots 7 form a pair of apertures in the otherwise closed face, the reinforcing rods 5 passing through those apertures which can then be closed down to a minimum cross-section in order to closely seal the plates 4, 4a against the reinforcing rod 5 preventing the ingress of L 6 any cement mix during the cement pouring procedures.

Each end of the case 1 is sealed off with a correspondingly shaped wooden plug 9. The wooden plug 9 also serves as a suitable material for nailing the assembled continuity strip to the concrete formwork while the cement mix is being poured and allowed to set.

Fig. 2 shows an alternative cross-section in the box i. This parallelapiped shape leaves a groove in the set concrete of the first pour which has sloping sides and is less likely to accumulate entrapped air bubbles in the region of otherwise sharp corners in the second pour.

Also, the embodiment shown in fig. 2 possesses an alternative design in the slots 3. It will be seen that S the plates 4 have a corresponding change along their side 0 00 15 edges so as to sealingly mate with the alternative slots oao oo 3. In other aspects the box 1 of fig. 2 is substantially O0 o identical to that of fig. 1.

0 o In assembly of the completed continuity strip, the o~O3 o~oO reinforcing rods 5, bent into the shape as shown in fig. 1 S 20 and la, and as described above, are placed in a staggered manner through the open face 2 of a box i, with their arms 6 aligned longitudinally of the box i. The rods Sare thus placed one at a time, commencing from one end of 0001?00 o 0 oo the open face 2, and after each rod 5 is so placed, a oo 00 a 25 plate 4 is inserted into and slid down along the sealing V slot 3. The last placed reinforcing rod 5 is finally 0 positioned so that the proximate slots 7 of the last 000'000 o 0 inserted plate 4 extend about the intermediate section of the reinforcing rod and, in cooperation with the previously placed plate 4, seals closely about the reinforcing rod 5. Once all of the rods 5 and plates 4 are thus placed, the two end plates 4 are nailed, by nails 11, to the wooden end plugs 9.

Fig. 4 shows a further alternative in the design of the box 1 in which the open face 2 extends substantially 7 across the entire width of the box 1. The slots 3 form part of the short side walls of the box 1. Each parallel side of each plate 4 includes a flange 18 bent to approximately 90 so as to fit closely within a respective slot 3, thus to provide the seal against wet concrete mix.

The plates 4 contain similar slots 7 as those previously described, and the open end of the box 1 is closed by a plug 9, again made out of wood or similar material. The flanges 18 may be approximately the depth of the slots 3, or alternatively they may be significantly longer so that the join between the box 1 and the plates 4 is effectively along a line intermediate the short sides 0 of the total assembly.

0: 15 Fig. 5 shows a further example of a suitable 0 o construction of the major components. In this case, the a 0 box 1 is replaced by a bottom plate 15 and a pair of side oo rails 16. each side rail 16 includes a top slot 3 and a oro bottom slot 17. The top slots 3 engage with respective flanges 18 of top plate 4 in the manner generally described earlier in the specification. The bottom slots 17 engage suitably bent flanges 19 of the bottom plate o 15. This version is more readily transported, as it takes 0 M up less volume for the same linear length of continuity strip. The example shown in Fig. 5 is of a generally parallelapiped cross-section, but it can equally be 6 rectangular or some other cross-section.

Also the relative location of slots 3, 17 and flanges oo 18, 19 of adjacent components can be interchanged. For example, the bottom plate 15 may include slots 17 and the side rails 16 may include bottom flanges 19.

During concreting operation the continuity strip is used substantially the same as previously known continuity strips. In predetermined positions it is nailed to concreting formwork, utilising the wooden end plugs 9, 1 3 ii 1 with the rear face 12 aligned substantially coplanar with the intended outer surface of the concrete and with the protruding sections of the reinforcing rods 5 within the volume to be filled with cement mix during the first pour. The first pour is allowed to cure, the formwork at least in part removed and the rear face 12 of the continuity strip exposed. The box 1 of the continuity strip is then removed so as to expose the arms 6, which were internal of the box 1, within an open keyway formed in the cured concrete by the external shape of the box 1.

The arms 6 will be extending generally parallel with the plates 4 and are straightened so as to extend generally perpendicularly from the concrete and across the formed keyway. This now fully exposes the plates 4 which can be easily removed, thus none of the original structure of the So case of the continuity strip is left in placc. The building procedure then continues by pouring the second pour of cement mix which will fill the keyway and fully h %embed the immediately previously exposed arms 6 of the reinforcing rods This continuity strip structure is very versatile, the various steel sheet cutting, folding and punching operations being easily automated. Further, the various important dimensions of the continuity strip, such as S 25 overall width, overall depth, distance across the bent reinforcing rods, and separation distance of the rods, are all easily adapted for particular purposes by appropriately selecting widths of sheet steel and appropriately setting the location of the various bends.

0 The production of the plates 4 can be effected by leading a continuous strip of predetermined width of galvanised steel firstly past a punching die which punches two longitudinally running elongate slots spaced a predetermined distance across the transverse direction of the sheet, and then passing the sheet through a guillotine ._i 9 press which cuts transversely across the sheet through the centres of the two slots so as to form an end of a plate 4 including the two spaced apart slots 7. Advantageously, the punch press which produces the elongate slots also produces punched edge indentations 13 seen in fig. 3a which shows a plate 4, and a plate 4a (in dotted outline) overlapping at the separation line 8. The side notches 13, 13a, allow the ends of the plates 4, 4a to overlap without necessitating a widening of the dimension of the slots 3.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the S 15 invention as broadly described. The present embodiments 0090 0 are, therefore, to be considered in all respects as 0 0) 6) 3 0 03 oaooon 0 00000 4QJh06 0 a a

Claims

2. A continuity strip as claimed in claim 1 comprising: an elongate hollow case section having an open elongate face; said plates closing the open face of the case so as to substantially entirely seal the case against entry of •cement mix and the like, the plates being removable from f I the case section and each being separable from adjacent plates at separation lines; and slots in the plates at the separation lines, each sized to closely fit a diameter of a reinforcing element lt of predetermined dimension.
3. A continuity strip as claimed in claim 2 wherein each plate includes a pair of said slots on each of two opposite ends, said ends and pair of slots of adjacent plates overlapping.
4. A continuity strip as claimed in claim 2 or 3 when 1 appended to claim 2 wherein two opposite parallel edges of said open face include a sliding sealing structure co-operative with two opposite parallel edges of said plates so as to locate and seal said plates relative to said case. A continuity strip as claimed in claim 2, 3 or 4, further including a plurality of reinforcing elements staggered along the elongate hollow case, each element residing partly internally of the case, partly externally of the case and passing through a pair of overlapping slots, the adjacent plates including the overlapping slots being positioned r 11 one toward the other so as to reduce the dimension of the overlapping slot to the diameter of the reinforcing element so as to seal the case about the element against the ingress of cement mix. 6o A continuity strip as claimed in claim 5 wherein said reinforcing elements are steel rods each having a generally U-shaped portion external of said continuity strip and extending from a respective pair of overlapping slots, and a pair of leg sections each being integral with an end of said U-section, the leg sections residing internally of the cont",uity strip.
7. A continuity strip as claimed in any one of the claims 2-6 wherein said case is parallelopiped shaped in cross-section, and said open face being at least a 15 substantial portion or width of a shorter one of the 00 parallel sides of the parallelopiped shaped case. 0 8. A continuity strip substantially as described herein 0 0 with reference to any one of the drawings.
9. A method of using a continuity strip comprising: 20 fixing the strip relative to formwork, 0 0 pouring cement mix into the formwork and allowing it to set, and 0:40.: removing a case section of the continuity strip so as Oa:. to leave in position only substantially planar plate 0040 o0400 25 sections of the continuity strip and then separately 0400 removing said plate sections so as to entirely remove said continuity strip and leave only a plurality of protruding arm reinforcing elements having been originally held in place relative to the formwork by the continuity strip. 30 10. A method of using a continuity strip as claimed in any one of claims 2-8, the method comprising fixing the strip relative to formwork so that parts of reinforcing elements external of the case reside in a volume to be concreted and a rear face of the case opposite the plates is clear of the the volume to be <ALI J/:U 01 .12 12 concreted, pouring cement mix into the formwork and allowing it to set, and removing the case section then removing each of the plates so as to leave only protruding arms of the reinforcing elements. DATED this 3rd day of November 1994 TOBY CONSTRUCTION PRODUCTS PTY. LTD. 0 Patent Attorneys for the 0 Applicant: S. F.B. RICE CO. 0 0 Ott 4 0 0 o 1000 4000