System of protecting the edges and construction joints of cast in place concrete slabs

• US 20060075706A1
• Filed: 04/22/2005
• Published: 04/13/2006
• Est. Priority Date: 08/01/2001
• Status: Active Grant

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Nigel K. Parkes, Russell Boxall
• Inventors: Boxall, Russell, Parkes, Nigel A., Harrison, Patrick
• Granted Patent: US 8,302,359 B2
• Time in Patent Office: Days
• US Class Current: 52/414
• CPC Class Codes: E01C 11/14 Dowel assembly ; Design or construction of reinforcements in the area of joints coupling devices for prefabricated units E01C5/005; combined with characteristic packings E01C11/08 - E01C11/12; removable holders E01C23/045
• CPC Class Codes: E04B 1/483 Shear dowels to be embedded in concrete
• CPC Class Codes: E04B 2005/322 with permanent forms for the floor edges
• CPC Class Codes: E04B 2005/324 with peripheral anchors or supports

Abstract

An improved joint edge assembly, of the type used in the construction of concrete slabs, is disclosed. The assembly comprises a longitudinal joint rail, preferably of steel, which is supported off the ground by formwork. The joint rail comprises first and second joint edge members that are connected to each other by interference-type connectors with self-release elements. A plurality of studs extends downward and outward from each of the joint edge members into the concrete slabs provide a positive mechanical connection between the slab and the joint rail. As the concrete shrinks during hardening, the self-release elements of the interference-type connectors allow the joint to freely open. The joint edge assembly thus provides a self-releasing joint between adjacent slab sections, and protects the edges of the adjacent slab sections from damage. A dowel aligner may also be integrated into the assembly, to allow proper positioning of dowels within the slab.

Claims

1. An improved joint edge assembly for the construction of jointed concrete slabs and protection of concrete slab joints, the concrete slabs shrinking during hardening, the assembly comprising:

a first elongated joint edge member;

a second elongated joint edge member;

interference-type connectors that connect the joint edge members to each other, said interference-type connectors also including release elements that release the joint edge members from each other under the force of the slabs shrinking during hardening;

whereby the assembly of the joint edge members and interference-type connectors may be placed for the joint edge members to form and thereby protect edges of a concrete slab joint, and whereby the slabs may be poured, and the joint edge members may release from each other under action of the slabs shrinking after pouring, to permitting relative movement of the joint edge members forming the joint and minimize slab cracking at and adjacent the joint during shrinkage.

2. A joint edge assembly as in claim 1, further comprising formwork mounting members connected to one of the joint edge members,

whereby the formwork mounting members may be mounted on temporary formwork and may support the assembly in position for the joint edge members to form the edges of the concrete slab joint.

3. An improved joint edge assembly as in claim 2 further comprising the temporary formwork and mounting members.

4. The apparatus of claim 3 further comprising a dowel aligner connected to the temporary formwork, extending into the region where the first concrete slab is to be poured,

whereby the dowel aligner permits the placement of dowels prior to the pouring of the adjacent concrete slab.

5. An improved joint edge assembly as in claim 1, wherein the elongated joint edge members are comprised of a steel angle section.

6. An improved joint edge assembly as in claim 1 further comprising a plurality of anchors extending from each side of the joint edge assembly into the regions where the adjacent slabs are to be poured.

7. An improved joint edge assembly as in claim 6, wherein the plurality of anchors are comprised of at least one steel stud with an expanded head.

8. A joint edge assembly as in claim 1, further comprising permanent formwork connected to one of the joint edge members.

9. The apparatus of claim 8 further comprising a dowel aligner connected to the permanent formwork, extending into the region where the first concrete slab is to be poured,

whereby the dowel aligner permits the placement of dowels prior to the pouring of the adjacent concrete slab.

10. An improved form assembly for use in the construction of concrete slabs and protection of joints in said concrete slabs after construction, the assembly placed on a ground surface defining a generally flat reference plane, the assembly comprising:

a longitudinal joint rail, the longitudinal joint rail comprising a first steel bar and a second steel bar, the steel bars formed of cold rolled steel bar sections and each having a major latitudinal dimension and a minor latitudinal dimension, the major latitudinal dimension, when in situ, extending generally perpendicular to the reference plane and the minor latitudinal dimension, when in situ, extending generally parallel to the reference plane, the steel rails being oriented, when in situ, with the major latitudinal dimensions thereof adjacent each other;

interference-type connectors that connect the joint rails in contact with one another, said connectors also including release elements that release the joint edge members from each other under the force of the slabs shrinking during hardening thereby forming releasable joint therebetween;

formwork along the joint rail and supporting the joint rail above the ground surface; and

a plurality of studs extending from each side of the form assembly into the regions where the adjacent slabs are to be poured.

11. The apparatus of claim 10, wherein the release element of the interference-type connector that connects the joint rails is comprised of a nylon material.

12. The apparatus of claim 10, wherein the longitudinal joint rail is comprised of a first steel angle member and a second steel angle member, the angle members each having a first angle flange and a second angle flange, the first angle flanges of the angle members, when in situ, extending generally perpendicular to the reference plane and the second angle flanges of the angle members, when in situ, extending generally parallel to the reference plane, the angle members being oriented, when in situ, with the first angel flanges thereof adjacent each other.

13. The apparatus of claim 10, wherein the formwork is temporary and is comprised of wood, a plurality of mounting brackets connect the joint rail to the temporary formwork, and the mounting brackets are secured to the formwork and secured to the joint rail.

14. The apparatus of claim 13, wherein the formwork is a standard 2″

lumber section with a thickness chosen according to the desired concrete slab thickness.

15. The apparatus of claim 10, wherein the formwork is permanent and is comprised of steel.

16. The apparatus of claim 10, wherein at least one of the studs has an expanded head.

17. The apparatus of claim 10 further comprising a dowel aligner connected to the formwork, extending into the region where the first concrete slab is to be poured,

whereby the dowel aligner permits the placement of dowels prior to the pouring of the adjacent concrete slab.

18. The apparatus of claim 17, wherein the dowel aligner is a base and a sleeve adapted to receive a load plate.

19. A method of forming an improved joint edge utilizing an improved joint edge assembly, for the construction of jointed concrete slabs and protection of concrete slab joints, the concrete slabs shrinking after pouring, the assembly comprising a first elongated joint edge member, a second elongated joint edge member, a plurality of anchors extending from each side of the form assembly into the regions where the adjacent slabs are to be poured, interference-type connectors that connect the joint edge members to each other, said interference-type connectors also including release elements that release the joint edge members from each other under action of the slabs shrinking during hardening, the method comprising:

placing the assembly of the joint edge members and interference-type connecting means for the joint edge members and formwork to form and thereby protect edges of a concrete slab joint,

pouring the slabs to the joint edge members, and

allowing the joint edge members to release from each other under action of the slabs shrinking during hardening with the anchors embedded therein and under action of the releasing elements of the interference-type connectors, permitting relative movement of the joint edge members forming the joint and minimize slab cracking at and adjacent to the joint during shrinkage and subsequently protecting the joint edge.

20. The method of claim 19 wherein the apparatus is further comprised of a dowel aligner connected to the form work, extending into the region where the first concrete slab is to be poured,

whereby the dowel aligner permits the placement of dowels prior to the pouring of the adjacent concrete slab.