TAPERED LOAD PLATE FOR TRANSFERRING LOADS BETWEEN CAST-IN-PLACE SLABS

• US 20080236091A1
• Filed: 06/09/2008
• Published: 10/02/2008
• Est. Priority Date: 09/13/2001
• Status: Active Grant

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Nigel K. Parkes, Russell Boxall
• Inventors: Boxall, Russell, Parkes, Nigel K.
• Granted Patent: US 7,716,890 B2
• Time in Patent Office: Days
• US Class Current: 52/741.1
• 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

Abstract

A tapered load plate transfers loads across a joint between adjacent concrete floor slabs. The top and bottom surfaces may taper from approximately 4 inches wide to a narrow substantially pointed end over a length of approximately 12 inches. The tapered load plate accommodates differential shrinkage of cast-in-place concrete slabs. When adjacent slabs move away from each other, the narrow end of the tapered load plate moves out of the void that it created in the slab thus allowing the slabs to move relative to one another in a direction parallel to the joint. Tapered load plates may be assembled into a load-plate basket with the direction of the taper alternating from one tapered load plate to the next to account for off-center saw cuts. A tapered load plate and an end cap may be used to provide load transfer across an expansion joint.

Claims

1. A system for transferring loads across a joint between concrete on-ground cast-in-place slabs, the system comprising:

a first concrete on-ground cast-in-place slab;

a second concrete on-ground cast-in-place slab;

an expansion joint separating the first and second slabs, wherein the joint is oriented substantially perpendicular to a substantially planar upper surface of the first slab, and a longitudinal axis of the joint is formed by an intersection of the joint and the upper surface of the first slab;

a load-plate end cap embedded within the first slab;

a tapered load plate that tapers from a relatively wide end continuing to a relatively narrow end, the wide end protruding into a portion of the end cap and the narrow end protruding into the second slab such that the load plate transfers between the first and second slabs a load applied to either of the slabs directed substantially perpendicular to the upper surface of the first slab; and

whereby the load plate restricts relative movement between the first and second slabs in a direction substantially perpendicular to the upper surface of the first slab, and the load plate moves farther into the end cap as the joint closes via the first and second slabs moving toward each other in a direction substantially perpendicular to the joint, such that, as the joint closes, the first and second slabs are allowed increasingly greater relative movement in a direction substantially parallel to the longitudinal axis of the joint.

2. The system of claim 1, further comprising:

a second load-plate end cap embedded within the second slab;

a second tapered load plate that tapers from a relatively wide end to a relatively narrow end, the wide end protruding into a portion of the second end cap and the narrow end protruding into the first slab such that the load plate transfers between the first and second slabs a load applied to either of the slabs directed substantially perpendicular to the upper surface of the first slab; and

whereby the second load plate restricts relative movement between the first and second slabs in a direction substantially perpendicular to the upper surface of the first slab, and the second load plate moves farther into the second end cap as the joint closes via the first and second slabs moving toward each other in a direction substantially perpendicular to the joint, such that, as the joint closes, the first and second slabs are allowed increasingly greater relative movement in a the direction substantially parallel to the longitudinal axis of the joint.

3. The system of claim 2, wherein the tapered load plates have a length of approximately 12 inches measured perpendicular to the joint.

4. The system of claim 2, further comprising a tapered-load-plate basket that positions the tapered load plates before the slabs are cast in place.

5. The system of claim 2, wherein the tapered load plates'"'"' wide end is approximately 4 inches long measured parallel to the joint.

6. The system of claim 5, wherein the tapered load plates'"'"' narrow ends taper to respective substantially pointed ends.

7. A system for transferring loads between a first concrete on-ground cast-in-place slab and a second concrete on-ground cast-in-place slab, the system comprising:

a joint separating the first and second slabs, at least a portion of the joint being initially defined by at least one of a saw or an edge form oriented substantially perpendicular to a substantially planar upper surface of the first slab, wherein a longitudinal axis of the joint is formed by an intersection of the saw or edge and the upper surface of the first slab; and

a first tapered load plate and a second tapered load plate that each protrude into the first and second slabs such that the load plates transfer between the first and second slabs a load applied to either of the slabs directed substantially perpendicular to the upper surface of the first slab;

whereby the tapered load plates restrict relative movement between the first and second slabs in a direction substantially perpendicular to the upper surface of the first slab, and the tapered load plates allow the joint to open by allowing the first and second slabs to move away from each other in a direction substantially perpendicular to the joint;

the tapered load plates each having a width measured parallel to the longitudinal axis of the joint; and

wherein the width of each tapered load plate generally tapers from a relatively wide end in one of the slabs to a relatively narrow end portion in the other slab such that, as the joint opens, the slabs are allowed increasingly greater relative movement in a direction substantially parallel to the longitudinal axis of the joint.

8. The system of claim 7, wherein the tapered load plates have a length of approximately 12 inches measured perpendicular to the joint.

9. The system of claim 7, wherein:

the tapered load plates'"'"' wide end is approximately 4 inches long measured parallel to the joint; and

the tapered load plates'"'"' narrow ends taper to respective substantially pointed ends.

10. The system of claim 7, further comprising a tapered-load-plate basket that positions the tapered load plates before the slabs are cast in place.

11. The system of claim 10, wherein the joint is a saw-cut control joint.

12. The system of claim 11, wherein the first tapered load plate'"'"'s wide end protrudes into the first slab and the second tapered load plate'"'"'s wide end protrudes into the second slab.

13. The system of claim 7, wherein the joint is a saw-cut control joint.

14. A system for transferring loads between a first concrete on-ground cast-in-place slab and a second concrete on-ground cast-in-place slab, the system comprising:

a joint separating the first and second slabs, at least a portion of the joint being initially defined by a partial depth saw cut that results in a crack below the saw cut, wherein a longitudinal axis of the joint is formed by an intersection of the saw cut and the upper surface of the first slab;

a first load plate and a second load plate that each protrude into the first and second slabs such that the load plates transfer between the first and second slabs a load applied to either of the slabs directed substantially perpendicular to the upper surface of the first slab;

whereby the load plates restrict relative movement between the first and second slabs in a direction substantially perpendicular to the upper surface of the first slab, and the load plates allow the joint to open by allowing the first and second slabs to move away from each other in a direction substantially perpendicular to the joint;

the load plates each having a width measured parallel to the longitudinal axis of the joint; and

wherein the width of each load plate generally tapers from a relatively wide portion near the joint to at least one relatively narrow end in at least one of the slabs such that, as the joint opens, the slabs are allowed increasingly greater relative movement in a direction substantially parallel to the longitudinal axis of the joint.

15. The system of claim 14, wherein the load plates taper to respective substantially pointed ends.

16. The system of claim 14, further comprising a load-plate basket that positions the load plates before the slabs are cast in place.

17. The system of claim 14, wherein one of the first load plate'"'"'s at least one relatively narrow ends protrudes into the first slab and one of the second load plate'"'"'s at least one relatively narrow ends protrudes into the second slab.

18. The system of claim 14, wherein the width of each load plate generally tapers from a relatively wide portion near the joint to a first relatively narrow end in the first slab and to a second relatively narrow end in the second slab.

19. The system of claim 18, wherein the first relatively narrow end tapers to a first substantially pointed end.

20. The system of claim 19, wherein the second relatively narrow end tapers to a second substantially pointed end.