Method and element for introducing shear forces into a concrete body, and concrete body

• US 6,763,646 B1
• Filed: 09/21/2000
• Issued: 07/20/2004
• Est. Priority Date: 09/21/2000
• Status: Expired due to Term

• Current Assignee: Reto Bonomo
• Original Assignee: Reto Bonomo
• Inventors: Bonomo, Reto
• Primary Examiner(s): Friedman, Carl D.
• Assistant Examiner(s): Nguyen, Chi Q
• Application Number:
  US09/666,998
• Time in Patent Office: 1,398 Days
• Field of Search: 527/241, 527/242, 52/20, 52/21, 521/671, 527/211, 526/00, 522/60, 527/421.6, 522/59, 522/231, 522/234, 522/235, 522/238, 522/239, 522/231.4, 524/31, 524/32, 524/34, 524/35
• US Class Current: 52/649.6
• CPC Class Codes: E04B 1/483 Shear dowels to be embedded in concrete
• CPC Class Codes: E04C 5/02 of low bending resistance
• CPC Class Codes: E04C 5/0645 Shear reinforcements, e.g. shearheads for floor slabs

Abstract

In an element (40b) for introducing shear forces into a concrete body a loop element (43b) is arranged on a shear force mandrel (41b), which loop element has an arc section (47b) in proximity to the surface of the concrete. When the element (40b) is subjected to a shear force (arrow 53) the arc section (47b) transmits this force to the concrete core inside the arc only through tensile forces in the loop element (43b) or in the arc element (47b). To absorb the resulting moment a second arc element (57b) aligned in the opposite direction is advantageously provided behind the first arc element (47b).

Claims

1. A method for introducing a shear force into a concrete body comprising:

(1) introducing the shear force into a shear force rod axially extending through a surface of the concrete body into the concrete body, said shear force rod being one of a shear force mandrel and a sleeve around the shear force mandrel;

(2) diverting the shear force from the shear force rod by at least one shear force strap completely in the concrete body and each connected to said shear force rod at (1) at least one first fixing point close to the surface of the concrete body and at (2) at least one second fixing point distant from the surface of the concrete body, each shear force strap comprising one or more loop elements extending from one of the first fixing points to one of the second fixing points, each loop element forming one single arc section between said first and said second fixing point, the arc section being formed around a concrete core that is being part of the concrete body; and

(3) transmitting the shear force into the concrete body by substantially only tensile forces in the shear force strap or straps.

2. The method according to claim 1, wherein the concrete body is a concrete slab.

3. The method of claim 2, wherein the shear force is introduced into the side face of the concrete slab.

4. The method according to claim 3, wherein an additional fiber reinforcement is provided to the concrete slab for distributing the tensile forces arising in the concrete slab.

5. An element for introducing a shear force into a concrete body comprising the combination of:

(a) at least one shear force rod axially extending through a surface of the concrete body into the concrete body, each said shear force rod being one of a shear force mandrel and a sleeve around the shear force mandrel; and

(b) at least one shear force strap completely within the concrete body and each attached to said shear force rod at (1) at least one first fixing point close to the surface of the concrete body and at (2) at least one second fixing point distant from the surface of the concrete body;

each said shear force strap capable of transmitting the shear force to the concrete body and comprising one or more loop elements extending from one of said first fixing points to one of said second fixing points, each loop element forming one single arc section between said first and said second fixing point.

6. An element according to claim 5, wherein each loop element is sufficiently flexible under the forces arising under load that it absorbs substantially only tensile forces.

7. An element according to claim 5, wherein each loop element has a substantially symmetrical arc section.

8. An element according to claim 5, wherein the arc section of each loop element is formed by a curved planar element of the loop element.

9. An element according to claim 8, wherein each loop element is formed of strip material which is relatively wide in relation to its thickness.

10. An element according to claim 5, wherein two loop elements are formed and are attached to the shear force rod.

11. An element according to claim 5, wherein two loop element are formed symmetrically with respect to the axis of the shear force rod.

12. An element according to claim 7, wherein rearwards of a first loop element a second loop element is arranged, the arc section of the second loop element being aligned in the opposite direction with respect to the arc section of said first loop element.

13. An element according to claim 5, and wherein the concrete body is reinforced with fiber reinforcement.

14. A method for introducing shear forces into a concrete body comprising:

(1) introducing the shear force into a shear force rod axially extending through a surface of the concrete body into the concrete body, said shear force rod being one of a shear force mandrel and a sleeve around the shear force mandrel;

(2) diverting the shear force from the shear force rod by at least one shear force strap, each connected to the shear force rod at two or more fixing points, each shear force strap comprising one or more loop elements extending from a first fixing point more close to the surface of the concrete body to a second fixing point more distant from the surface of the concrete body, each loop element forming one single arc section between said first and said second fixing point around a concrete core, the concrete core being part of the concrete body; and

(3) transmitting the shear force into the concrete body by substantially only tensile forces in the shear force strap or straps.

15. An element for introducing shear forces into a concrete body comprising the combination of:

(a) a first shear force rod being a shear force mandrel; and

(b) at least one first shear force strap attached to said shear force mandrel at two or more fixing points;

each said first shear force strap comprising one or more loop elements extending from a first fixing point to a second fixing point, each loop element forming one single arc section between said first and said second fixing point;

(c) a second shear force rod being a sleeve around the shear force mandrel; and

(d) at least one second shear force strap attached to said sleeve at two or more fixing points;

each said second shear force strap comprising one or more loop elements extending from a first fixing point to a second fixing point, each loop element forming one single arc section between said first and said second fixing point.

16. An element according to claim 15, wherein each loop element is sufficiently flexible under the forces arising under load that it absorbs substantially only tensile force.

17. An element according to claim 15, wherein each loop element has a substantially symmetrical arc section.

18. An element according to claim 15, wherein the arc section of each loop element is formed by a curved planar element of the loop element.

19. An element according to claim 15, wherein each loop element is formed of strip material which is relatively wide in relation to its thickness.

20. An element according to claim 15, wherein two loop elements are formed and are attached to the shear force mandrel.

21. An element according to claim 20, wherein two loop elements are formed symmetrically with respect to the axis of the shear force mandrel.

22. An element according to claim 15, wherein two loop elements are formed and are attached to the sleeve.

23. An element according to claim 22, wherein two loop elements are formed symmetrically with respect to the axis of the sleeve.

24. A method for introducing a shear force into a concrete body, said shear force working between the concrete body and a second body distinct from the concrete body, said concrete body and said second body being connected by at least one shear force rod extending along a longitudinal axis, said shear force rod consisting of a shear force mandrel and a sleeve around said mandrel, said shear force mandrel having a first portion and adjacent to said first portion on said longitudinal axis a second portion, and said sleeve being arranged around and fitted to said first portion, said concrete body being connected to said sleeve around said first portion of the shear force mandrel and said second body being connected to said second portion of said shear force mandrel, said method comprising the steps of:

(1) connecting each of at least one shear force strap at first and second spaced apart fixing points to said sleeve such that the shear force strap forms at least one arc-like loop element extending from one of the first fixing points to one of the second fixing points;

(2) arranging the shear force rod such that each shear force strap can be embedded in the concrete body to be molded and that the first fixing point is close to the surface of the concrete body and the second fixing point is distant from the surface of the concrete body to be molded, and that the second portion of the shear force mandrel is arranged outside the concrete body to be molded;

(3) embedding the shear force strap connected to the shear force rod in a concrete made forming after curing said concrete body, wherein each arc-like loop element encloses a concrete core that is part of the concrete body;

(4) connecting said second body to said second portion of said shear force mandrel such that a potential shear force acting between said concrete body and said second body is introduced into said concrete body by said shear force rod, provoking tensile forces only in the arc-like loop element enclosing said concrete core.

25. A method for introducing a shear force into a concrete body, said shear force working between the concrete body and a second body distinct from the concrete body, said concrete body and said second body being connected by at least one shear force rod extending along a longitudinal axis, said shear force rod consisting of a shear force mandrel and a sleeve around said mandrel, said shear force mandrel having a first portion and adjacent to said first portion on said longitudinal axis a second portion, and said sleeve being arranged around and fitted to said second portion, said concrete body being connected to said first portion of the shear force mandrel and said second body being connected to said sleeve around said second portion of said shear force mandrel, said method comprising the steps of:

(1) connecting each of at least one shear force strap at first and second spaced apart fixing points to said first portion of said shear force mandrel such that the shear force strap forms at least one arc-like loop element extending from one of the first fixing points to one of the second fixing point;

(2) arranging the shear force rod such that each shear force strap can be embedded in the concrete body to be molded and that the first fixing point is close to the surface of the concrete body and the second fixing point is distant from the surface of the concrete body to be molded, and that the second portion of the shear force mandrel is arranged outside the concrete body to be molded;

(3) embedding the shear force strap connected to the shear force rod in a concrete mass forming after curing said concrete body, wherein each arc-like loop element encloses a concrete core that is part of the concrete body;

(4) connecting a second distinct body to said sleeve such that a potential shear force acting between said concrete body and said second body is introduced into the concrete body by the shear force rod, provoking tensile forces only in the arc-like loop elements enclosing said concrete core.

26. An element for introducing shear forces from outside of a concrete body by a shear force mandrel through a surface of said concrete body into said concrete body, comprising the combination of:

(1) said shear force mandrel extending along its longitudinal axis and having a first portion and on said longitudinal axis adjacent to said first portion a second port; and

(2) a sleeve arranged and fitting around said first portion of said shear force mandrel, said shear force mandrel and said sleeve being movable relative to each other along said longitudinal axis;

(3) at least one first shear force strap, each attached at two or more fixing points to said sleeve around said first portion of said shear force mandrel;

(4) each first shear force strap comprising one first loop element extending from a first fixing point close to said second portion of said shear force mandrel to a second fixing point more distant from said second portion of said shear force mandrel, said loop element being formed of strip material being formed of strip material and forming one single continuous arc section between said first and said second fixing point.

27. An element for introducing shear forces from outside of a concrete body by a shear force mandrel through a surface of said concrete body into said concrete body, comprising the combination of:

(1) said shear force mandrel extending along a longitudinal axis and having a first portion and on said longitudinal axis adjacent to said first portion a second portion; and

(2) a sleeve arranged and fitting around said first portion of said shear force mandrel, said shear force mandrel and said sleeve being movable relative to each other along said longitudinal axis;

(3) at least one second shear force strap, each attached at two or more fixing points to said second portion of said shear force mandrel;

(4) each of said second shear force straps comprising one first loop element extending from a first fixing point close to said first portion of said shear force mandrel to a second fixing point more distant from said first portion of said shear force mandrel, said loop element being formed of strip material being formed of strip material and forming one single continuous arc section between said first and said second fixing point.