System for transferring loads between cast-in-place slabs

• US 6,354,760 B1
• Filed: 11/18/1998
• Issued: 03/12/2002
• Est. Priority Date: 11/26/1997
• Status: Expired due to Term

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Nigel K. Parkes, Russell Boxall
• Inventors: Boxall, Russell, Parkes, Nigel K.
• Primary Examiner(s): Hartmann, Gary S.
• Application Number:
  US09/195,320
• Time in Patent Office: 1,210 Days
• Field of Search: 404/47, 404/48, 404/50, 404/51, 404/55, 404/56, 404/57, 404/58, 404/53, 404/54, 404/40, 404/41, 14/731, 104/138.1, 472/85, 525/851, 525/861, 446/108, 446/111, 403/292, 403/294, 403/405.1, 403/406.1, 403/408.1
• US Class Current: 404/56
• 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

Abstract

A load plate for transferring loads between a first cast-in-place slab and a second cast-in-place slab separated by a joint. The load plate having a substantially tapered end having substantially planar upper and lower surfaces adapted to protrude into and engage the first slab, and the load plate being adapted to transfer between the first and second slabs a load directed substantially perpendicular to the intended upper surface of the first slab. A blockout sheath embedded within the first slab could also be included. The block out sheath could have a substantially planar top surface and a substantially planar bottom surface substantially parallel to the upper surface of the first slab. The top and bottom surfaces of the blockout sheath could each have a width, measured parallel to an intersection between the joint surface and the upper surface of the first slab, that substantially decreases away from the joint surface. The width of the blockout sheath could be substantially greater than the width of the substantially tapered end at each corresponding depth along the substantially tapered end and the blockout sheath, such that the substantially tapered end could move within the sheath in a direction parallel to the intersection between the upper surface of the first slab and the joint surface.

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;

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

a load plate including a substantially tapered end, the end having upper and lower surfaces, the upper and lower surfaces protruding into the first slab, and a second end protruding into the second slab such that the load plate transfers between the first and second slabs a load applied to either slab directed substantially perpendicular to the upper surface of the first slab;

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 allows the joint to open by allowing the first and second slabs to move away from each other in a direction substantially perpendicular to the inner surface of the edge form;

the load plate having a width measured parallel to the longitudinal axis of the joint and a length measured parallel to the upper surface of the first slab; and

the width of the load plate being;

substantially greater than or equal to the length of the load plate, and

generally larger closer to the joint and generally smaller farther away from the joint such that, as the joint opens, increasingly greater relative movement of the first and second slabs in a direction substantially parallel to the longitudinal axis of the joint is allowed.

2. The system of claim 1, wherein a height of the load plate measured perpendicular to the upper surface of the first slab is substantially less than one-eighth of a largest width of the load plate.

3. The system of claim 2, wherein the height of the load plate is approximately one half of an inch.

4. The system of claim 1, wherein the load plate is substantially square and is oriented within the joint such that the upper and lower surfaces of the load plate are substantially parallel to the upper surface of the first slab and such that a first pair of opposing comers of the load plate are oriented substantially parallel to the longitudinal axis of the joint and a second pair of opposing corners of the load plate are oriented substantially perpendicular to the longitudinal axis of the joint.

5. Apparatus for use in transferring a load across a joint between first and second cast-in-place slabs, the joint having a substantially planar joint surface substantially perpendicular to a substantially planar intended upper surface of the first slab, the apparatus comprising:

a blockout sheath adapted to be embedded within the first slab such that a substantially planar top surface and a substantially planar bottom surface of the blockout sheath are substantially parallel to the intended upper surface of the first slab, the top and bottom surfaces of the blockout sheath each having a width parallel to an intersection between the joint surface and the upper surface of the first slab, the width of the top and bottom surfaces of the blockout sheath substantially decreasing away from the joint surface; and

a load plate having a substantially tapered end and a remaining portion, the tapered end having substantially planar upper and lower surfaces, the substantially tapered end being adapted to be inserted into the blockout sheath, the upper and lower surfaces of the substantially tapered end being adapted to cooperatively engage the substantially planar upper and lower surfaces of the blockout sheath, the remaining portion of the load plate being adapted to be embedded in the second slab;

the load plate and the blockout sheath being adapted to transfer between the first and second slabs any load applied to either the first or second slab in a direction perpendicular to the intended upper surface of the first slab; and

the load plate and the blockout sheath being adapted to allow increasingly greater relative movement of the first and second slabs in a direction parallel to the width of the blockout sheath as the first or second slab moves away from the joint.

6. The apparatus of claim 5 wherein the blockout sheath and the substantially tapered end of the load plate each have a depth perpendicular to the joint surface, the width of the blockout sheath being substantially greater than the width of the substantially tapered end at each corresponding depth along the substantially tapered end and the blockout sheath, such that the substantially tapered end can move within the sheath in a direction parallel to the intersection between the upper surface of the first slab and the joint surface.

7. The apparatus of claim 5 wherein the blockout sheath further comprises means for initially centering the substantially tapered end of the load plate within the width of the sheath.

8. The apparatus of claim 6 wherein the blockout sheath further comprises a plurality of deformable centering fins for initially centering the substantially tapered end of the load plate within the width of the sheath.

9. The apparatus of claim 5 wherein the substantially tapered end of the load plate comprises:

a substantially pointed end.

10. The apparatus of claim 5 wherein a largest width of the substantially tapered end of the load plate is substantially no less than twice the depth of the substantially tapered end of the load plate.

11. The apparatus of claim 5 wherein the substantially tapered end of the load plate further comprises a height measured perpendicular to the upper surface of the load plate, the height being substantially less than one-eighth the largest width of the substantially tapered end of the load plate.

12. A load plate kit having component parts capable of being assembled during creation of a joint between first and second cast-in-place slabs, the joint being initially defined by an inner surface of an edge form, a substantially planar intended upper surface of the first slab being substantially perpendicular to the inner surface of the edge form, the kit comprising:

a. a mounting plate adapted to be attached to the edge form;

b. a blockout sheath adapted to be attached to the mounting plate such that a substantially planar top surface and a substantially planar bottom surface of the blockout sheath protrude into a space to be occupied by the first slab, the top and bottom surfaces of the blockout sheath being substantially parallel to the intended upper surface of the first slab, the top and bottom surfaces of the blockout sheath each having a width parallel to an intersection between the edge form and the intended upper surface of the first slab, the width of the top and bottom surfaces of the blockout sheath substantially decreasing away from the joint; and

c. a load plate having a substantially tapered end, the end having substantially planar upper and lower surfaces, the end being adapted to be inserted into the blockout sheath, the upper and lower surfaces of the first end adapted to cooperatively engage the substantially planar upper and lower surfaces of the blockout sheath, the load plate and blockout sheath being adapted to transfer between the first and second slabs a load applied to either slab, the load being directed substantially perpendicular to the intended upper surface of the first slab after;

i. the first slab has been poured and has hardened,

ii. the edge form and mounting plate have been removed from the first slab,

iii. the substantially tapered end of the load plate has been inserted into the blockout sheath such that a remaining portion of the load plate protrudes into a space to be occupied by the second slab, and

iv. the second slab has been poured and has hardened.

13. The kit of claim 12 wherein the blockout sheath and the substantially tapered end of the load plate each have a depth perpendicular to the inner surface of the edge form, the width of the blockout sheath being substantially greater than the width of the substantially tapered end at each corresponding depth along the substantially tapered end and the blockout sheath, such that the substantially tapered end can move within the sheath substantially parallel to the intended upper surface of the first slab.

14. The kit of claim 13 wherein the blockout sheath further comprises means for initially centering the substantially tapered end of the load plate within the width of the sheath.

15. The kit of claim 13 wherein the blockout sheath further comprises:

a plurality of deformable centering fins for initially centering the substantially tapered end of the load plate within the width of the sheath.

16. The kit of claim 12 wherein the substantially tapered end of the load plate comprises:

a substantially pointed end.

17. The kit of claim 12 wherein a largest width of the substantially tapered end of the load plate is substantially no less than twice the depth of the substantially tapered end of the load plate.

18. The kit of claim 12 wherein the load plate further comprises a height measured perpendicular to the upper surface of the first slab, the height being substantially less than one-eighth of a largest width of the substantially tapered end of the load plate.

19. 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;

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

a plurality of load plates each having upper and lower surfaces, the upper and lower surfaces protruding into the first slab and into the second slab such that the load plates transfer between the first and second slabs a load applied to either slab 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 inner surface of the edge form;

the load plates each having a largest width measured parallel to the longitudinal axis of the joint and a largest length measured perpendicular to the inner surface of the edge form, the largest width of the load plates being substantially the same as the largest length of the load plates; and

the load plates having a height, measured perpendicular to the upper surface of the first slab, that is substantially less than one-eighth of the largest width of the load plates.

20. The system of claim 19, wherein the height of the load plates is approximately one half of an inch.

21. At a joint separating a first concrete on-ground cast-in-place slab from a second concrete on-ground cast-in-place slab, at least a portion of the joint being initially defined by an inner surface of an edge form, a substantially planar upper surface of the first slab being substantially perpendicular to the inner surface of the edge form, a longitudinal axis of the joint being formed by an intersection of the inner surface of the edge form and the upper surface of the first slab, the improvement comprising:

a load plate adapted for transferring loads between the first cast-in-place slab and the second cast-in-place slab, the load plate including;

a substantially tapered end, the end having substantially planar upper and lower surfaces, the upper and lower surfaces of the first end being adapted to protrude into the first slab; and

a second end protruding into the second slab such that the load plate transfers, between the first and second slabs, a load applied to either slab directed substantially perpendicular to the upper surface of the first slab;

the load plate restricting relative movement between the first and second slabs in a direction substantially perpendicular to the upper surface of the first slab;

the load plate allowing the joint to open by allowing the first and second slabs to move away from each other in a direction substantially perpendicular to the inner surface of the edge form; and

the substantially tapered end of the load plate having a width measured parallel to the longitudinal axis of the joint, the width of the tapered end being generally larger closer to the joint and generally smaller farther away from the joint such that, as the joint opens, the substantially tapered end of the load plate allows increasingly greater relative movement of the first and second slabs in a direction substantially parallel to the longitudinal axis of the joint.

22. The improvement according to claim 21, wherein the substantially tapered end of the load plate comprises:

a substantially pointed end.

23. The improvement according to claim 21, wherein a largest width of the substantially tapered end of the load plate is substantially no less than twice a depth, measured perpendicular to the joint, of the substantially tapered end of the load plate.

24. The improvement according to claim 21, wherein a height of the load plate measured perpendicular to the upper surface of the first slab is substantially less than one-eighth of a largest width of the substantially tapered end of the load plate.

25. The improvement according to claim 24, wherein the height of the load plate is approximately one half of an inch.

26. The improvement according to claim 25, wherein the load plate is substantially square and is oriented within the joint substantially parallel to the intended upper surface of the first slab and such that there is an angle of approximately 45 degrees between the longitudinal axis of the joint and each of the four sides of the load plate.