WO2009114898A1

WO2009114898A1 - Expansion joint with looped membrane configuration

Info

Publication number: WO2009114898A1
Application number: PCT/AU2009/000308
Authority: WO
Inventors: Robert James Trad; David John Denny
Original assignee: EXPANSION TECHNOLOGY SYSTEMS Pty Ltd
Current assignee: EXPANSION TECHNOLOGY SYSTEMS Pty Ltd
Priority date: 2008-03-19
Filing date: 2009-03-17
Publication date: 2009-09-24
Anticipated expiration: 2010-09-19
Also published as: AU2009225941A1

Abstract

There is an expansion joint for installation between facing edges of adjacent structures (7) which are separated by a gap (6). The joint in a position of use includes strip sets (8, 11) and (12, 13) affixed adjacent the respective edges and a section of membrane 9 disposed between and secured to said strip sets and extending loosely across said gap (6) to thereby seal said gap over a range of thermal expansion and contraction.

Description

EXPANSION JOINT WITH LOOPED MEMBRANE CONFIGURATION

FIELD OF THE INVENTION

This invention relates to expansion joints. More particularly butsnot exclusively, it discloses an improved form of expansion joint for concrete decks or the like and a method of installing said joint.

BACKGROUND OF THE INVENTION

Concrete decks must be fitted with expansion joints at regular intervals across their surface to reduce the build up of thermal stresses from temperature variations. One typical example of an expansion joint currently used with; elevated concrete decks in car parks is shown schematically in cross section by figure 1. A metal stop strip 1 is fixed to one side of the joint and the free edge ion the other side allows the joint to move underneath. A closed cell backing rod 2 is laid along the top of the metal stop strip 1. A single layer membrane 3 is draped over the backing rod 2 and fixed to both the sides of the joint with epoxyi 4.

Disadvantages with such prior art joints include the following:

- Upon installation, it is difficult for an installer to fix the membrane 3 at the sides with uncured epoxy 4, drape over backing rod 2 land fix it down with epoxy 4 on the other side. Pressure also needs to be placed on the sides of the membrane 3 while the epoxy 4 sets.

- Sharp edges form beneath the membrane 3 in the epoxy 4. These create wear points where movement and stretching can rupture the membrane 3.

- It is impossible to assess the quality and performance of such prior art joints once they have been installed. Methods of installation vary and the quality of workmanship directly affects the joint's performance. - The joint cannot be easily adapted to accommodate varying gap widths and extreme movements.

SUMMARY OF THE INVENTION

It is therefore an object of this invention to ameliorate the aforementioned disadvantages and accordingly an expansion joint is disclosed for installation between facing edges of adjacent structures which are separated by a gap, said joint in a position of use including strip sets affixed adjacent respective facing edges and a section of membrane disposed between and secured to said strip sets and extending loosely across said gap to thereby seal said gap over a range of thermal expansion and contraction.

Preferably said strip sets comprise respective pairs of strips in spaced apart substantially facing relationship with the membrane disposed therebetween.

It is further preferred that said section membrane extends loosely across said gap in a bowed or looped configuration.

It is further preferred that said respective strip sets include a cover strip set affixed adjacent one of said edges and a skid strip set affixed adjacent another of said edges, the cover strip set extending across the gap and substantially over said sldd strip set.

It is further preferred that said cover strip set includes a raised portion spaced above the skid strip set and said gap which define a protective cavity for the looped membrane.

It is further preferred that portions of the cover strip set on each side of said cavity are folded into a zigzag shape.

It is further preferred that the membrane is sealed to the strip sets and structure edges by an epoxy compound or the like. :

In accordance with another aspect of the invention a method is disclosed for installing the aforementioned expansion joint between two facing edges of adjjacent structures separated by a gap, said method including the steps of:-

procuring at least a partial pre-assembly of said expansion joint with said cover strip, skid strip and an edge strip in an inverted or upside down configuration,

- temporarily securing said pre-assembly with removable clip means for storage and transport

preparing a substrate on facing edges thereof,

- installing components of said pre-assembly along the length of said gap,

fixing the membrane to said substrate,

- fixing said pre-assembly to the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

Currently preferred examples of the invention will now be described with reference to the attached drawings in which :

figure 2 is a schematic cross-sectional view of a surface mounted joint according to a first embodiment of said invention, figure 3 is a schematic cross-sectional and elevated view of a skid strip for use with the expansion joint of figure 2 figure 4 is a schematic cross-sectional view of an edge strip for use with the expansion joint of figure 2 figure 5 is a schematic cross-sectional and elevated view of a cover strip for use with the expansion joint of figure 2 figure 6 is a schematic cross-sectional view of a guide strip for use with the expansion joint of figure 2, figure 7 is a schematic cross-sectional view of removable clips for use with the assembly in figure 2, figure 8 is a schematic cross-sectional view of an expansion joint according to a second embodiment of the invention, figure 9 is a schematic cross-sectional view of the preferred form of strip set for use with the expansion joint of figure 8, : figure 10 is a schematic cross-sectional view of an expansion joint according to a third embodiment of the invention, figure 11 is a schematic perspective view of an expansion joint according to a fourth embodiment of the invention, and figure 12 is a schematic cross-sectional view of an expansion joint according to a fifth embodiment of the invention

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings the strips shown in edge section are, in practice, of varying length depending upon the extent of the joint which they comprise. Referring first to figures 2 to 6 there is a surface mounted expansion joint indicated generally as 5. It is installed over a thermal expansion joint 6 between adjacent elevated concrete decks 7 as may be used to construct a multistory parking station or the like. The joint with this embodiment comprises a set of cover strips 8, 11 which are secured by a pin 15 to the left deck and a set of skid strips 12, 13 which are secured by a pin 15 A to the right hand deck as shown Each set of strips sandwiches an outer portion of a sealing membrane 9 extending between them. The cover strip set 8, 11 extends over the gap 6 as well as a substantial part of the skid strip set 12, 13 and is shaped to form a central cavity 9A. The inner guide plate 11 terminates at one end of this cavity 9A so that the membrane 9 is free to loop back toward the skid strips 12, 13. Preferably an epoxy compound or other suitable adhesive/sealant is packed into the side cavities 10 as well as between the strips and membrane to prevent moisture penetration past the joint.

The currently preferred method of installing an expansion joint according to the invention is as follows:-

- Prior to installation the guide strip 8 is inverted and the ^iembrane 9 is wrapped around the strip 11 and tucked it into the folds of the strip 8. It is necessary that the edge of the membrane 9 folds around the edge of the strip 11 so later applied epoxy 10 can properly bed in it. The membrane 9 is sandwiched between the strips 8 and 11. The membrane 9 is pre-cut;to a width which with this invention allows for free movement without excess material. The length of strip 8 is preferably the same as the length of strip 11. The length of strips 8 and 11 are less than the membrane 9 to allow both ends of said membrane to be exposed and later lapped and fixed.

- In continuation of the said method of assembly, and still in an inverted position, strip 13 is placed upside down between the loose edge of the membrane 9B and strip 8. The edge of the membrane 913 should be wrapped around the strip 13 so later applied epoxy 10 can properly bed it in. Strip 12 is inverted and placed upside down under the exposed membrane 9 and the strip 13 with the membrane edge 9B is pressed into strip 12 leaving sufficient membrane 9B exposed to be later epoxied 10 directly to the surface. The length of the strips 12 and 13 are preferably less than the membrane 9 so the membrane 9 can later be lapped and fixed.

The surfaces along the edges of the concrete decks 7 are prepared in such a way that they are smooth, clean and dry, and free of contaminants, damage and protrusions which may affect the adhesion of the later applied epoxy 10 to the surfaces. Any required repairs are done prior to installation.

In an inverted position epoxy 10 is applied to the underneath of the outer edge of strip 12 while lifting the membrane edge 9B to ensure ample epoxy between the membrane edge 9B and said strip 12; Apply more epoxy 10 to the outer edge of the strip 12 to create an overburden sufficient to bed the side of the assembly to the surface of the deck 7. Turn the assembly, right side up and place the epoxy coated side onto the surface of the deck 7 while aligning the nose 13A of strip 13 so it slightly overhangs the edge of the gap 6. The assembly will open outwards to allow room to fix dowa Ensure that the edge of the membrane 9B is completely bedded in epoxy 10.

- Fix the side of the assembly by drilling through holes in strip 12 into the substrate then insert mechanical fixing pins 15A.

- The unfixed side of the assembly is then turned upside down over the fixed side of the assembly and the epoxy 10 is applied to the underneath side of the outer edge of the strip 11 while lifting the membrane edge 9A to ensure ample epoxy 10 between the membrane edge 9A and said strip 11. Apply more epoxy 10 to the outer edge of the cover strip 8 to create an overburden sufficient to bed the side of the assembly to the surface of the deck 7. Turn the assembly right side up and place the epoxy coated side onto the surface of the deck 7 while aligning the inside edge of the strip 11 so it overhangs the other edge of the gap 6. Ensure the edge of the membrane 9A is completely bedded in epoxy 10.

- Fix the side of the assembly by drilling through predrilled holes in plate 8 into the substrate then inserting mechanical fixing pins 15.

- Assemblies as shown in figure 2 can be installed end to end along the expansion joint and lapping the membrane 9 can be done while the ends of the membrane are exposed. The lapped end sections of membrane can be epoxied 10 into place onto the substrate 7 and sections of skid strip 12 and cover strip 8 can be fixed into place using epoxy 10 and the mechanical fixing pins. Without limiting the scope of the invention the following materials are currently preferred for use in constructing the expansion joint:

Cover Strip 8 - Metal or Plastic .

Guide Strip 11 - Metal or Plastic

Edge Strip ] 3 - Metal or Plastic

Skid Strip 12 - Metal or Plastic

Membrane 9 - Butyl Rubber (Preferably About 1 - 1.5mm

Thick)

Epoxy 10 - Sikador 31 or BASF 1446

Mechanical fixing pins 15 - Nylon knock- ins .

With the second, third and fourth embodiments of the invention shown in figures 8 to 11 the components which correspond in function to those of figure 1 to .7 are indentifϊed by the same numbers which however are primed (') (") and ('") to distinguish them.

In the case of the second embodiment the strip sets 15B (see figures 8 and 9) sit on top of the slab or deck surface T to each side of the gap 6'. They are of similar construction. Each comprises two elongated strips 16, 17 which extend along the length of the joint and define a raised casing. The strip 16 is bifurcated and joins with strip 17 to; form a U shaped passage through which an end of the membrane 9' is located. The casing is then packed with an epoxy compound 17A to complete the assembly. If required pins 15' can be used to additionally secure the strips in place while the epoxy cures. As the membrane 9' is elevated off the deck surface it is protected from abrasion and allowed stress free movement for increased service life.

With the third and fourth embodiments shown in figures 10 and 11 the strip sets are set in horizontal rebates 20 in the slabs on each side of the gap 6" or fixed to the vertical inside walls of the gap 6'". A cover strip 21 is then secured in any suitable manner over the installed membrane.

With the fifth embodiment of the invention shown in figure 12 a get of upper and lower cover strips 22 and 23 are contoured upwardly from an epoxy bed 24 on the left deck 25. There is a bearing plate 26 formed at the free end of the upper cover strip 22 which is adapted to engage skid strip 27 on the opposite deck 28 and also forms a niche 29 with the lower strip 23 through which the membrane 30 loops. The upper cover strip 22 also has a flange 31 extending off its opposite fixed end which is secured by a pin 32. The opposite set of skid strips 27, 32 are of similar design to the aforementioned strips 16, 17 of the second embodiment and are similarly secured in a bed 33 of epoxy by a pin 34. Both the lower cover strip and skid strip 32 have inner flanges 35 ,36 to contain the epoxy bed at the inner edges of the joint 37.

It will thus be appreciated that this invention at least in the form of the embodiments disclosed provides a novel and improved expansion joint and ms≥thod of construction of said joint. Clearly however the examples described are only the currently preferred forms of the invention and a wide variety of modifications may be made which would be apparent to a person skilled in the art. For example the cross-sectional shape and configuration of the strips and fixing pins may be changed according to installation requirements or design preference. The invention extends to the use of materials other than those currently specified.

Claims

The claims:

1. An expansion joint for installation between facing edges of adjacent structures which are separated by a gap₅ said joint in a position or use including strip sets affixed adjacent respective facing edges and a section of membrane disposed between and secured to said strip sets and extending loosely across said gap to thereby seal said gap over ia range of thermal expansion and contraction.

2. The expansion joint as claimed in claim 1 wherein said section of membrane extends loosely across said gap in a bowed or looped configuration.

3. The expansion joint as claimed in claim 2 wherein said respective snip sets include a cover strip set affixed adjacent one of said edges and a skid strip set affixed adjacent the other of said edges, the cover strip set extending across the gap and substantially over said skid strip set.

4. The expansion joint as claimed in claim 3 wherein said cover snip set and said skid strip set include respective pairs of strips in, spaced apart substantially facing relationship with at least part of said membrane located therebetween.

5. The expansion joint as claimed in claim 3 wherein said cover strip set includes a raised portion spaced above said skid strip set and gap which defines a cavity for said membrane .

6. The expansion joint as claimed in claim 3 wherein portions of said cover strip set are folded into a zigzag shape.

7. The expansion joint as claimed in claim 1 wherein said membrane extends loosely across said gap in a substantially horizontal looped configuration.

8. The expansion joint as claimed in claim 3 wherein said cover strip set and said skid strip set are secured adjacent said respective facing edges by pins.

9. The expansion joint as claimed in claim 3 wherein said skid strip set includes a downwardly sloped overhang portion which protrudes into said gap-

10. The expansion joint as claimed in claim 1 wherein said membrane is secured to said snip sets at least in part by an epoxy compound.

11. The expansion joint as claimed in claim 1 wherein at least one of said strip sets includes a pair of snips with one of said strips being bifurcated to join with another of said strips to form a U shaped passage through which said membrane curves and said at least one strip set being secured to one of said edges with an epoxy adhesive and a pin located away from said membrane.