WO2012110699A1 - Tension reinforcement of a fastening plate in a concrete element - Google Patents

Tension reinforcement of a fastening plate in a concrete element Download PDF

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Publication number
WO2012110699A1
WO2012110699A1 PCT/FI2012/050140 FI2012050140W WO2012110699A1 WO 2012110699 A1 WO2012110699 A1 WO 2012110699A1 FI 2012050140 W FI2012050140 W FI 2012050140W WO 2012110699 A1 WO2012110699 A1 WO 2012110699A1
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WO
WIPO (PCT)
Prior art keywords
concrete
anchor bar
elongated anchor
distal end
anchorage part
Prior art date
Application number
PCT/FI2012/050140
Other languages
French (fr)
Inventor
Jan Bujnak
Original Assignee
Peikko Group Oy
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Filing date
Publication date
Application filed by Peikko Group Oy filed Critical Peikko Group Oy
Publication of WO2012110699A1 publication Critical patent/WO2012110699A1/en

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
    • E04B1/18—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons
    • E04B1/20—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons the supporting parts consisting of concrete, e.g. reinforced concrete, or other stonelike material
    • E04B1/21—Connections specially adapted therefor
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
    • E04B1/18—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons
    • E04B1/24—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons the supporting parts consisting of metal
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
    • E04B1/38—Connections for building structures in general
    • E04B1/41—Connecting devices specially adapted for embedding in concrete or masonry
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
    • E04B1/38—Connections for building structures in general
    • E04B1/48—Dowels, i.e. members adapted to penetrate the surfaces of two parts and to take the shear stresses
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/01—Reinforcing elements of metal, e.g. with non-structural coatings
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
    • E04B1/38—Connections for building structures in general
    • E04B1/41—Connecting devices specially adapted for embedding in concrete or masonry
    • E04B2001/4192—Connecting devices specially adapted for embedding in concrete or masonry attached to concrete reinforcing elements, e.g. rods or wires
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/01—Reinforcing elements of metal, e.g. with non-structural coatings
    • E04C5/06—Reinforcing elements of metal, e.g. with non-structural coatings of high bending resistance, i.e. of essentially three-dimensional extent, e.g. lattice girders
    • E04C5/0645—Shear reinforcements, e.g. shearheads for floor slabs

Definitions

  • the invention relates to a method for reinforcing a fastening plate embedded in a concrete element to prevent a concrete cone break off from the concrete element as defined in the preamble of the independent claim 1 .
  • the invention also relates to a concrete element as defined in the preamble of the independent claim 7.
  • the invention also relates to a tension reinforcement system for embedding in a concrete element as defined in the preamble of the independent claim 9.
  • the invention also relates to a use of a double headed anchor bar as defined in the preamble of the independent claim 13.
  • Fastening plates are used in concrete structures to transfer loads with the help of anchor parts to the concrete structure.
  • the anchor parts When tensile load is applied to the fastening plate the anchor parts will bear to the concrete and the concrete structure will start to deform along the anchor part.
  • the deformation developing from the concentrated force introduced to the concrete by the anchor part may result to a concrete cone failure.
  • the concrete cone failure is a failure in a concrete structure in which the concrete fracture appears in a cone shape.
  • the concrete cone failure is usually the result of a tension load.
  • hanger reinforcements in the form of stirrups located directly adjacent the anchor load-transfer zone and adequately anchored in the anticipated failure cone and in the surrounding concrete structure.
  • This hanger reinforcement is required to be well anchored in the concrete cone in direction parallel to the fastening and tied together in perpendicular direction.
  • the hanger reinforcement is a continuous ribbed bar bended in U-shape and the parts of the U-bend parallel to the fastening have to be placed side-by-side to it.
  • a disadvantage with the known hanger reinforcements is that they need to be long enough to ensure the transfer of tensile forces from concrete to the reinforcement. Such length may be difficult to achieve especially with very compact anchorage systems. In such cases, the full resistance of the steel hanger reinforcement may not be exploited. As a consequence, the reinforcement has to be overdesigned with regards to the anchorage strength of the hanger reinforcement inside of the concrete cone, leading to high consumption of material and in construction sites the material use must be optimized.
  • the other disadvantage with the known hanger reinforcement is that they are made on measure on site by bending straight bars. This requires additional work and operations on site.
  • the object of the invention is to provide a tension reinforcement method and system for embedding in concrete elements which solves the above mentioned problems.
  • the method for reinforcing a fastening plate embedded in a concrete element of the invention is characterized by the definitions of the independent claim 1 .
  • a concrete element of the invention is correspondingly characterized by the definitions of the independent claim 7.
  • the tension reinforcement system for embedding in a concrete element of the invention is characterized by the definitions of the independent claim 9.
  • a use of a double headed anchor bar is characterized by the definitions of the independent claim 13.
  • the invention is based on a new kind of method for reinforcing a fastening plate embedded in a concrete element, such as a slab wall or floor or concrete columns, comprising concrete to prevent a concrete cone break off from the concrete element.
  • the method comprises the steps of using a fastening plate comprising a plate part positioned to the surface of the concrete element and at least one anchorage part fastened to the plate part, the anchorage part having a proximal end and a distal end, wherein the proximal end being fastened to the plate part and the distal end being intended to be positioned inside the concrete, arranging the fastening plate to the concrete before the concrete hardens, and fastening the fastening plate to the concrete by means of concrete hardening.
  • the method also comprises the steps of using reinforcement means comprising an elongated anchor bar having a proximal end and a distal end, wherein at least one of the proximal end and the distal end is provided with a head, arranging the elongated anchor bar to the concrete before the concrete hardens by arranging the elongated anchor bar a distance away from the anchorage part, and by arranging the proximal head of the elongated anchor bar adjacent to the anchorage part and by arranging the distal head of the elongated anchor bar further away from the plate part, i.e.
  • the invention is also based on a new kind of a concrete element, such as a slab wall or a slab floor or a column comprising concrete, wherein the concrete element comprises a tension reinforcement system arranged in the concrete element, said tension reinforcement system comprising a fastening plate comprising a plate part arranged at a surface of the concrete element and at least one anchorage part fastened thereto, the anchorage part having a proximal end and a distal end, in which the proximal end is fastened to the plate part and the distal end is positioned inside the concrete, and reinforcement means for transferring forces from the fastening plate to the concrete to prevent a concrete cone break off from the concrete element.
  • a concrete element such as a slab wall or a slab floor or a column comprising concrete
  • the concrete element comprises a tension reinforcement system arranged in the concrete element, said tension reinforcement system comprising a fastening plate comprising a plate part arranged at a surface of the concrete element and at least one anchorage part fastened thereto, the anchorage
  • the reinforcement means comprises an elongated anchor bar having a proximal end and a distal end, in which at least one of the proximal and distal end of the elongated anchor bar is provided with a head, said elongated anchor bar is positioned with its longitudinal axis transverse to the surface of the concrete element in a distance away from the fastening plate and that the distal end of the elongated anchor bar extends further away from the surface of the concrete element in which the plate part is arranged than the distal end of the anchorage part.
  • the invention is also based on a new kind of a tension reinforcement system for embedding in a concrete element such as a wall or a floor comprising concrete, wherein the tension reinforcement system comprising a fastening plate comprising a plate part to be positioned at a surface of the concrete element and at least one anchorage part fastened thereto, the anchorage part having a proximal end and a distal end, in which the proximal end being fastened to the plate part and the distal end being intended to be positioned inside the concrete, and reinforcement means for transferring forces from the fastening plate to the concrete to prevent a concrete cone break off from the concrete element, both the fastening plate and the reinforcement means being intended to be arranged in the concrete before the concrete hardens and further to be fastened to the concrete by means of concrete hardening.
  • the tension reinforcement system comprising a fastening plate comprising a plate part to be positioned at a surface of the concrete element and at least one anchorage part fastened thereto, the anchorage part having a
  • the reinforcement means comprising an elongated anchor bar having a proximal end and a distal end, and at least one of the proximal and distal end of the elongated anchor bar being provided with a head, and said elongated anchor bar being intended to be positioned with its longitudinal axis transverse to the surface of the concrete element in a distance away from the fastening plate and the distal end of the elongated anchor bar being intended to extend further away from the surface of the concrete element in which the plate part is intended to be positioned than the distal end of the anchorage part.
  • the invention is further based on a use of a double headed anchor in a concrete element to reinforce a fastening plate arranged in the concrete element to prevent a concrete cone failure.
  • the method for reinforcing a fastening plate and the tension reinforcement system according to the invention provide for advantages to allow using less steel reinforcement because of the higher anchorage strength. Also the simple installation of the elongated anchor bar is a big advantage in a construction site.
  • the elongated anchor bars may be prefabricated in factory, delivered on site and installed more rapidly and with higher precision.
  • figure 1 shows a concrete element with a tension reinforcement element according to the invention
  • figure 2 shows the concrete element as shown in figure 1 from another perspective.
  • the figure 1 shows an example of a method for reinforcing a fastening plate 1 embedded in a concrete element 2.
  • the concrete element 2 may be a flat slab such as a wall or a floor or a foundation but it also can be a column.
  • a fastening plate 1 is arranged in a concrete element 2 such that the plate part 3 of the fastening plate 1 is arranged on the surface of the concrete element 2.
  • An anchorage part 4 is arranged to the plate part 3 such that the proximal end 4a of the anchorage part 4 is fastened to the plate part 3 by a permanent attachment or by a releasable attachment.
  • the distal end 4b of the anchorage part 4 is positioned inside the concrete element 2.
  • the anchorage part 4 is preferably arranged perpendicular to the surface of the concrete element 2.
  • An elongated anchor bar 5 is arranged in this case on both sides of the anchorage part 4 such that the proximal end 5a of the anchor bar is near the anchorage part 4 and preferable nearer to the proximal end 4a of the anchorage part 4 than the distal end 4b of the anchorage part 4.
  • the distal end 5b of the anchor bar 5 is arranged further away from the plate part 3 than the distal end 4b of the anchorage part 4.
  • the distal end 5b of the anchor bar 5 is arranged further away from the surface of the concrete element than the distal end 4b of the anchorage part 4.
  • the elongated anchor bar 5 may also be arranged parallel to the anchorage part 4.
  • the elongated anchor bar 5 is arranged on both sides of the anchorage part 5.
  • the elongated anchor bars 5 arranged on each side of the fastening plate 1 may be looped with a transverse reinforcement member 6. So the anchor bars 5 arranged on sides of the anchorage part 4 are looped together by a transverse reinforcement member 6 which is preferably a stirrup.
  • Figure 2 shows the same example of a method for reinforcing a fastening plate 1 embedded in a concrete element 2 as in the figure 1 but from another perspective.
  • Figure 2 shows that the elongated anchor bar 5 is arranged preferably at the same level as the anchorage part 4 but the distal end 5b of the anchor bar 5 extends further away from the plate part 3 of the fastening plate 1 than the distal end 4b of the anchorage part 4.
  • the transverse reinforcement member 6 is preferably arranged near the proximal ends (4a, 5a) of both the anchor bar 5 and the anchorage part 4 and inside the anticipated concrete cone which is shown with a dashed line in the figure.
  • the elongated anchor bar 5 comprises heads at both ends of the anchor bar 5.
  • the double headed anchor bar 5 is used in concrete to reinforce fastening plate 1 arranged in the concrete to prevent concrete cone failure.
  • the elongated anchor bar 5 has heads at both ends and the anchor bar 5 is arranged in the concrete such that one head is anchored into the anticipated concrete cone and the second head is anchored to the concrete body. There is preferably no physical contact between the fastening plate 1 and the elongated anchor bar 5 as such.
  • the dashed line in the figure shows the anticipated concrete cone.
  • the double headed anchor bar 5 is arranged on each side of the fastening plate 1 in order to balance the forces acting on both sides of the anchorage part 4.
  • the double headed anchor bars 5 are preferably tied together by a stirrup to balance a force coming from a bending moment. This tie between the two double headed anchor bars 5 is arranged by looping the stirrup around the double headed anchor bars 5 such that the anchorage part 4 of the fastening plate 1 stays inside the stirrup and such that the stirrup is not in contact with the anchorage part 4.
  • the anchorage part 4 may however be in contact with the stirrup but not necessarily.
  • the elongated anchor bar 5 is looped by a stirrup such that the stirrup is arranged to that part of the elongated anchor bar 5 which lies inside the anticipated cone section.
  • the stirrup carries transverse tension due to eccentricity between the elongated anchor bar 5 and the fastening plate 1 .
  • the double headed anchor bar 5 is arranged near to the anchorage part 4 of the fastening plate 1 but they do have spacing between.
  • the spacing between the double headed anchor bar 5 and the anchorage part 4 is influences the value of maximum force that can be transferred between the two elements, i.e. between the anchor bar 5 and the anchorage part 4.
  • the optimal spacing is approximately 0,5 x the length of the anchorage part.
  • the optimal spacing is 10 cm.
  • the spacing between the double headed anchor bar and the anchorage part can be from 0,25 x the length of the anchorage part up till 0,75 x the length of the anchorage part.
  • the spacing is from 0,35 x the length of the anchorage part up till 0,65 x the length of the anchorage part.
  • the anchorage part 4 When tensile load is applied to the fastening plate 1 , the anchorage part 4 will bear to the concrete and the volume of the concrete will start to deform. In other words the anchorage part 4 will apply pressure to the concrete and the concrete start to deform to the direction of the free concrete part. In the case where there is no reinforcement the deformation of the concrete will continue, cracks will develop and finally a concrete cone will separate from the concrete structure. In the case of a double headed anchor bar 5 present in the structure, the deformed concrete will bear to the heads of the anchor bar 5 and this will act as a support to the compressed concrete and the development of the concrete cone is prevented by the elongated anchor bar 5.
  • the tensile load will be anchored to the concrete structure by the elongated anchor bar 5 and preferably by the heads of the elongated anchor bar 5. So the elongated anchor bar 5 having preferably heads at both ends of the anchor bar 5 tie the breakaway or becoming-breakaway concrete cone to the rest of the concrete body. The elongated anchor bar 5 becomes activated after the shear crack is formed or during the formation.
  • the load transfer between the fastening plate 1 and the elongated anchor bar 5 or between the anchorage part 4 and the elongated anchor bar 5 comprises a diagonal force formed in the concrete between the head of the anchorage part 4 and the head of the elongated anchor bar 5.
  • a horizontal component of the diagonal force may push the elongated anchor bar 5 away from the fastening plate 1 and a stirrup may be used to balance this to avoid transverse cracking of concrete.
  • a transverse reinforcement member may be used to balance the horizontal component of the diagonal force.
  • concrete element stands for all kinds of thin, compact or structural concrete elements or flat slabs that can be used in construction building such as in columns, walls, floors, foundations.

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Abstract

The invention concerns a method for reinforcing a fastening plate (1) embedded in a concrete element (2) comprising concrete to prevent a concrete cone break off from the concrete element (2), in which a fastening plate (1) is positioned at the surface of the concrete element (2) and reinforcement means comprises an elongated anchor bar (5). The invention concerns also a concrete element (2), a tension reinforcement system and use of a double headed anchor bar (5).

Description

Tension reinforcement of a fastening plate in a concrete element
Field of the invention
The invention relates to a method for reinforcing a fastening plate embedded in a concrete element to prevent a concrete cone break off from the concrete element as defined in the preamble of the independent claim 1 .
The invention also relates to a concrete element as defined in the preamble of the independent claim 7.
The invention also relates to a tension reinforcement system for embedding in a concrete element as defined in the preamble of the independent claim 9.
The invention also relates to a use of a double headed anchor bar as defined in the preamble of the independent claim 13.
Fastening plates are used in concrete structures to transfer loads with the help of anchor parts to the concrete structure. When tensile load is applied to the fastening plate the anchor parts will bear to the concrete and the concrete structure will start to deform along the anchor part. The deformation developing from the concentrated force introduced to the concrete by the anchor part may result to a concrete cone failure. The concrete cone failure is a failure in a concrete structure in which the concrete fracture appears in a cone shape. The concrete cone failure is usually the result of a tension load.
It is known to reinforce fastening plates by hanger reinforcements in the form of stirrups located directly adjacent the anchor load-transfer zone and adequately anchored in the anticipated failure cone and in the surrounding concrete structure. This hanger reinforcement is required to be well anchored in the concrete cone in direction parallel to the fastening and tied together in perpendicular direction. The hanger reinforcement is a continuous ribbed bar bended in U-shape and the parts of the U-bend parallel to the fastening have to be placed side-by-side to it.
A disadvantage with the known hanger reinforcements is that they need to be long enough to ensure the transfer of tensile forces from concrete to the reinforcement. Such length may be difficult to achieve especially with very compact anchorage systems. In such cases, the full resistance of the steel hanger reinforcement may not be exploited. As a consequence, the reinforcement has to be overdesigned with regards to the anchorage strength of the hanger reinforcement inside of the concrete cone, leading to high consumption of material and in construction sites the material use must be optimized. The other disadvantage with the known hanger reinforcement is that they are made on measure on site by bending straight bars. This requires additional work and operations on site.
Objective of the invention
The object of the invention is to provide a tension reinforcement method and system for embedding in concrete elements which solves the above mentioned problems.
Short description of the invention
The method for reinforcing a fastening plate embedded in a concrete element of the invention is characterized by the definitions of the independent claim 1 .
Preferred embodiments of the method for reinforcing a fastening plate embedded in a concrete element are defined in the dependent claims 2 to 6.
A concrete element of the invention is correspondingly characterized by the definitions of the independent claim 7.
Preferred embodiment of the concrete element is defined in the dependent claims 8.
The tension reinforcement system for embedding in a concrete element of the invention is characterized by the definitions of the independent claim 9.
Preferred embodiment of the tension reinforcement system is defined in the dependent claims 10 to 12.
A use of a double headed anchor bar is characterized by the definitions of the independent claim 13.
The invention is based on a new kind of method for reinforcing a fastening plate embedded in a concrete element, such as a slab wall or floor or concrete columns, comprising concrete to prevent a concrete cone break off from the concrete element. The method comprises the steps of using a fastening plate comprising a plate part positioned to the surface of the concrete element and at least one anchorage part fastened to the plate part, the anchorage part having a proximal end and a distal end, wherein the proximal end being fastened to the plate part and the distal end being intended to be positioned inside the concrete, arranging the fastening plate to the concrete before the concrete hardens, and fastening the fastening plate to the concrete by means of concrete hardening. The method also comprises the steps of using reinforcement means comprising an elongated anchor bar having a proximal end and a distal end, wherein at least one of the proximal end and the distal end is provided with a head, arranging the elongated anchor bar to the concrete before the concrete hardens by arranging the elongated anchor bar a distance away from the anchorage part, and by arranging the proximal head of the elongated anchor bar adjacent to the anchorage part and by arranging the distal head of the elongated anchor bar further away from the plate part, i.e. further away from the surface of the concrete element in which the plate part is positioned, than the distal head of the anchorage part and fastening the elongated anchor bar to the concrete by means of concrete hardening. The invention is also based on a new kind of a concrete element, such as a slab wall or a slab floor or a column comprising concrete, wherein the concrete element comprises a tension reinforcement system arranged in the concrete element, said tension reinforcement system comprising a fastening plate comprising a plate part arranged at a surface of the concrete element and at least one anchorage part fastened thereto, the anchorage part having a proximal end and a distal end, in which the proximal end is fastened to the plate part and the distal end is positioned inside the concrete, and reinforcement means for transferring forces from the fastening plate to the concrete to prevent a concrete cone break off from the concrete element. The reinforcement means comprises an elongated anchor bar having a proximal end and a distal end, in which at least one of the proximal and distal end of the elongated anchor bar is provided with a head, said elongated anchor bar is positioned with its longitudinal axis transverse to the surface of the concrete element in a distance away from the fastening plate and that the distal end of the elongated anchor bar extends further away from the surface of the concrete element in which the plate part is arranged than the distal end of the anchorage part.
The invention is also based on a new kind of a tension reinforcement system for embedding in a concrete element such as a wall or a floor comprising concrete, wherein the tension reinforcement system comprising a fastening plate comprising a plate part to be positioned at a surface of the concrete element and at least one anchorage part fastened thereto, the anchorage part having a proximal end and a distal end, in which the proximal end being fastened to the plate part and the distal end being intended to be positioned inside the concrete, and reinforcement means for transferring forces from the fastening plate to the concrete to prevent a concrete cone break off from the concrete element, both the fastening plate and the reinforcement means being intended to be arranged in the concrete before the concrete hardens and further to be fastened to the concrete by means of concrete hardening. The reinforcement means comprising an elongated anchor bar having a proximal end and a distal end, and at least one of the proximal and distal end of the elongated anchor bar being provided with a head, and said elongated anchor bar being intended to be positioned with its longitudinal axis transverse to the surface of the concrete element in a distance away from the fastening plate and the distal end of the elongated anchor bar being intended to extend further away from the surface of the concrete element in which the plate part is intended to be positioned than the distal end of the anchorage part.
The invention is further based on a use of a double headed anchor in a concrete element to reinforce a fastening plate arranged in the concrete element to prevent a concrete cone failure.
The method for reinforcing a fastening plate and the tension reinforcement system according to the invention provide for advantages to allow using less steel reinforcement because of the higher anchorage strength. Also the simple installation of the elongated anchor bar is a big advantage in a construction site. The elongated anchor bars may be prefabricated in factory, delivered on site and installed more rapidly and with higher precision.
List of figures
In the following the invention will be described in more detail by referring to the figures, which
figure 1 shows a concrete element with a tension reinforcement element according to the invention, and
figure 2 shows the concrete element as shown in figure 1 from another perspective. Detailed description of the invention
The figure 1 shows an example of a method for reinforcing a fastening plate 1 embedded in a concrete element 2. The concrete element 2 may be a flat slab such as a wall or a floor or a foundation but it also can be a column. A fastening plate 1 is arranged in a concrete element 2 such that the plate part 3 of the fastening plate 1 is arranged on the surface of the concrete element 2. An anchorage part 4 is arranged to the plate part 3 such that the proximal end 4a of the anchorage part 4 is fastened to the plate part 3 by a permanent attachment or by a releasable attachment. The distal end 4b of the anchorage part 4 is positioned inside the concrete element 2. The anchorage part 4 is preferably arranged perpendicular to the surface of the concrete element 2. An elongated anchor bar 5 is arranged in this case on both sides of the anchorage part 4 such that the proximal end 5a of the anchor bar is near the anchorage part 4 and preferable nearer to the proximal end 4a of the anchorage part 4 than the distal end 4b of the anchorage part 4. The distal end 5b of the anchor bar 5 is arranged further away from the plate part 3 than the distal end 4b of the anchorage part 4. At the same time the distal end 5b of the anchor bar 5 is arranged further away from the surface of the concrete element than the distal end 4b of the anchorage part 4. The elongated anchor bar 5 may also be arranged parallel to the anchorage part 4.
In this preferred embodiment of the invention the elongated anchor bar 5 is arranged on both sides of the anchorage part 5. Although the figure shows only anchor bars 5 arranged with regard to one anchorage part 5 the same applies to the other anchorage part 5 as well. The elongated anchor bars 5 arranged on each side of the fastening plate 1 may be looped with a transverse reinforcement member 6. So the anchor bars 5 arranged on sides of the anchorage part 4 are looped together by a transverse reinforcement member 6 which is preferably a stirrup.
Figure 2 shows the same example of a method for reinforcing a fastening plate 1 embedded in a concrete element 2 as in the figure 1 but from another perspective. Figure 2 shows that the elongated anchor bar 5 is arranged preferably at the same level as the anchorage part 4 but the distal end 5b of the anchor bar 5 extends further away from the plate part 3 of the fastening plate 1 than the distal end 4b of the anchorage part 4. The transverse reinforcement member 6 is preferably arranged near the proximal ends (4a, 5a) of both the anchor bar 5 and the anchorage part 4 and inside the anticipated concrete cone which is shown with a dashed line in the figure. According to another embodiment of the invention the elongated anchor bar 5 comprises heads at both ends of the anchor bar 5. The double headed anchor bar 5 is used in concrete to reinforce fastening plate 1 arranged in the concrete to prevent concrete cone failure. The elongated anchor bar 5 has heads at both ends and the anchor bar 5 is arranged in the concrete such that one head is anchored into the anticipated concrete cone and the second head is anchored to the concrete body. There is preferably no physical contact between the fastening plate 1 and the elongated anchor bar 5 as such. The dashed line in the figure shows the anticipated concrete cone.
The double headed anchor bar 5 is arranged on each side of the fastening plate 1 in order to balance the forces acting on both sides of the anchorage part 4. The double headed anchor bars 5 are preferably tied together by a stirrup to balance a force coming from a bending moment. This tie between the two double headed anchor bars 5 is arranged by looping the stirrup around the double headed anchor bars 5 such that the anchorage part 4 of the fastening plate 1 stays inside the stirrup and such that the stirrup is not in contact with the anchorage part 4. The anchorage part 4 may however be in contact with the stirrup but not necessarily. Further the elongated anchor bar 5 is looped by a stirrup such that the stirrup is arranged to that part of the elongated anchor bar 5 which lies inside the anticipated cone section. The stirrup carries transverse tension due to eccentricity between the elongated anchor bar 5 and the fastening plate 1 . The double headed anchor bar 5 is arranged near to the anchorage part 4 of the fastening plate 1 but they do have spacing between. The spacing between the double headed anchor bar 5 and the anchorage part 4 is influences the value of maximum force that can be transferred between the two elements, i.e. between the anchor bar 5 and the anchorage part 4. The optimal spacing is approximately 0,5 x the length of the anchorage part. In other words if the anchorage part is 20 cm long the optimal spacing is 10 cm. However the spacing between the double headed anchor bar and the anchorage part can be from 0,25 x the length of the anchorage part up till 0,75 x the length of the anchorage part. Advantageously the spacing is from 0,35 x the length of the anchorage part up till 0,65 x the length of the anchorage part.
When tensile load is applied to the fastening plate 1 , the anchorage part 4 will bear to the concrete and the volume of the concrete will start to deform. In other words the anchorage part 4 will apply pressure to the concrete and the concrete start to deform to the direction of the free concrete part. In the case where there is no reinforcement the deformation of the concrete will continue, cracks will develop and finally a concrete cone will separate from the concrete structure. In the case of a double headed anchor bar 5 present in the structure, the deformed concrete will bear to the heads of the anchor bar 5 and this will act as a support to the compressed concrete and the development of the concrete cone is prevented by the elongated anchor bar 5. So the tensile load will be anchored to the concrete structure by the elongated anchor bar 5 and preferably by the heads of the elongated anchor bar 5. So the elongated anchor bar 5 having preferably heads at both ends of the anchor bar 5 tie the breakaway or becoming-breakaway concrete cone to the rest of the concrete body. The elongated anchor bar 5 becomes activated after the shear crack is formed or during the formation.
The load transfer between the fastening plate 1 and the elongated anchor bar 5 or between the anchorage part 4 and the elongated anchor bar 5 comprises a diagonal force formed in the concrete between the head of the anchorage part 4 and the head of the elongated anchor bar 5. A horizontal component of the diagonal force may push the elongated anchor bar 5 away from the fastening plate 1 and a stirrup may be used to balance this to avoid transverse cracking of concrete. In other words a transverse reinforcement member may be used to balance the horizontal component of the diagonal force.
In the above description the term concrete element stands for all kinds of thin, compact or structural concrete elements or flat slabs that can be used in construction building such as in columns, walls, floors, foundations.
It is apparent to a person skilled in the art that as technology advanced, the basic idea of the invention can be implemented in various ways. The invention and its embodiments are therefore not restricted to the above examples, but they may vary within the scope of the claims.

Claims

Claims
1 . A method for reinforcing a fastening plate (1 ) embedded in a concrete element (2), such as a slab wall or floor, comprising concrete to prevent a concrete cone break off from the concrete element (2), the method comprising using a fastening plate (1 ) comprising a plate part (3) positioned to the surface of the concrete element (2) and at least one anchorage part (4) fastened to the plate part (3), the anchorage part (4) having a proximal end (4a) and a distal end (4b), wherein the proximal end (4a) being fastened to the plate part (3) and the distal end (4b) being intended to be positioned inside the concrete,
arranging the fastening plate (1 ) to the concrete before the concrete hardens, and
fastening the fastening plate (1 ) to the concrete by means of concrete hardening, characterized by
using reinforcement means comprising an elongated anchor bar (5) having a proximal end (5a) and a distal end (5b), wherein at least one of the proximal end (5a) and the distal end (5b) is provided with a head,
arranging the elongated anchor bar (5) to the concrete before the concrete hardens by arranging the elongated anchor bar (5) a distance away from the anchorage part (4), and by arranging the proximal head (5a) of the elongated anchor bar (5) adjacent to the anchorage part (4) and by arranging the distal head (5b) of the elongated anchor bar (5) further away from the surface of the concrete element (2), in which the plate part (3) is positioned, than the distal head (4b) of the anchorage part (4),
fastening the elongated anchor bar (5) to the concrete by means of concrete hardening.
2. The method according to claim 1 , characterized by arranging the elongated anchor bar (5) parallel to the anchorage part (4).
3. The method according to claim 1 or 2, characterized by arranging the elongated anchor bar (5) next to the anchorage part (4) such that the spacing between the elongated anchor bar (5) and the anchorage part (4) is from 0,35 x the length of the anchorage part (4) up till 0,65 x the length of the anchorage part (4).
4. The method according to any of claims 1 - 3, characterized by arranging at least one elongated anchor bar (5) on each side of the fastening plate (1 ).
5. The method according to claim 4, characterized by looping the elongated anchor bars (5) arranged on each side of the fastening plate (1 ) with a transverse reinforcement member (6).
6. The method according to any of claims 1 - 5, characterized in that the elongated anchor bar (5) comprises a head on both the proximal end (5a) and the distal end (5b) of the elongated anchor bar (5).
7. A concrete element (2) such as a slab wall or a slab floor comprising concrete, wherein the concrete element (2) comprises a tension reinforcement system arranged in the concrete element (2), said tension reinforcement system comprising:
a fastening plate (1 ) comprising a plate part (3) arranged at a surface of the concrete element (2) and at least one anchorage part (4) fastened thereto, the anchorage part (4) having a proximal end (4a) and a distal end (4b), in which the proximal end (4a) is fastened to the plate part (3) and the distal end (4b) is positioned inside the concrete, and
reinforcement means for transferring forces from the fastening plate (1 ) to the concrete to prevent a concrete cone break off from the concrete element (2), characterized in that
the reinforcement means comprises an elongated anchor bar (5) having a proximal end (5a) and a distal end (5b), in which at least one of the proximal (5a) and distal end (5b) of the elongated anchor bar (5) is provided with a head,
said elongated anchor bar (5) is positioned in a distance away from the fastening plate (1 ) and that the distal end (5b) of the elongated anchor bar (5) extends further away from the surface of the concrete element (2) in which the plate part (3) is arranged than the distal end (4b) of the anchorage part (4).
8. The concrete element according to claim 7, characterized in that the elongated anchor bar (5) is positioned with its longitudinal axis transverse to the surface of the concrete element (2).
9. A tension reinforcement system for embedding in a concrete element
(2) such as a wall or a floor comprising concrete, wherein the tension reinforcement system comprising
a fastening plate (1 ) comprising a plate part (3) to be positioned at a surface of the concrete element (2) and at least one anchorage part (4) fastened thereto, the anchorage part (4) having a proximal end (4a) and a distal end (4b), in which the proximal end (4a) being fastened to the plate part
(3) and the distal end (4b) being intended to be positioned inside the concrete, and
reinforcement means for transferring forces from the fastening plate (1 ) to the concrete to prevent a concrete cone break off from the concrete element (2),
both the fastening plate (1 ) and the reinforcement means being intended to be arranged in the concrete before the concrete hardens and further to be fastened to the concrete by means of concrete hardening, characterized
by the reinforcement means comprising an elongated anchor bar (5) having a proximal end (5a) and a distal end (5b),
by at least one of the proximal (5a) and distal end (5b) of the elongated anchor bar (5) being provided with a head,
by said elongated anchor bar (5) being intended to be positioned in a distance away from the fastening plate (1 ) and
by the distal end (5b) of the elongated anchor bar (5) being intended to extend further away from the surface of the concrete element (2), in which the plate part (3) is intended to be positioned than, the distal end (4b) of the anchorage part (4).
10. The tension reinforcement system according to claim 9, characterized in that the elongated anchor bar (5) being intended to be positioned with its longitudinal axis transverse to the surface of the concrete element (2).
1 1 . The tension reinforcement system according to claim 9 or 10, characterized in that the elongated anchor bar (5) being intended to be positioned parallel to the anchorage part (4).
12. The tension reinforcement system according to any of claims 9 - 1 1 , characterized in that the elongated anchor bar (5) being intended to be positioned next to the anchorage part (4) such that the spacing between the elongated anchor bar (5) and the anchorage part (4) is from 0,35 x the length of the anchorage part (4) up till 0,65 x the length of the anchorage part (4).
13. Use of a double headed anchor bar (5) in a concrete element (2) to reinforce a fastening plate (1 ) arranged in the concrete element (2) to prevent concrete cone failure.
PCT/FI2012/050140 2011-02-17 2012-02-14 Tension reinforcement of a fastening plate in a concrete element WO2012110699A1 (en)

Applications Claiming Priority (2)

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FI20115154 2011-02-17
FI20115154A FI20115154L (en) 2011-02-17 2011-02-17 Tensile reinforcement for a fastening plate in a concrete element

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20190071862A1 (en) * 2016-04-08 2019-03-07 Wobben Properties Gmbh Connection element, wind turbine tower ring segment and method for connecting two wind turbine tower ring segments
US10829945B2 (en) * 2016-04-11 2020-11-10 Tectonic Facades Limited Construction assembly
DE102020121852A1 (en) 2020-08-20 2022-02-24 Fischerwerke Gmbh & Co. Kg Anchor holder, anchor rail and arrangement with the anchor rail

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Publication number Priority date Publication date Assignee Title
DE10312701A1 (en) * 2003-03-21 2004-10-14 Krummel, Gerhard, Dipl.-Ing. Foundation anchor bolt fixing straddles anchor bolt by double-headed setbolts to cover anchor bolt head and engage this assisted by supplementary crossbolt with setbolts engaging foundation reinforcement.
JP2009102909A (en) * 2007-10-24 2009-05-14 Tokyo Gas Co Ltd Embedded hardware and method of mounting the same
JP2011021434A (en) * 2009-07-17 2011-02-03 Takenaka Komuten Co Ltd Structure for reinforcing concrete member, and building with the same

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10312701A1 (en) * 2003-03-21 2004-10-14 Krummel, Gerhard, Dipl.-Ing. Foundation anchor bolt fixing straddles anchor bolt by double-headed setbolts to cover anchor bolt head and engage this assisted by supplementary crossbolt with setbolts engaging foundation reinforcement.
JP2009102909A (en) * 2007-10-24 2009-05-14 Tokyo Gas Co Ltd Embedded hardware and method of mounting the same
JP2011021434A (en) * 2009-07-17 2011-02-03 Takenaka Komuten Co Ltd Structure for reinforcing concrete member, and building with the same

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20190071862A1 (en) * 2016-04-08 2019-03-07 Wobben Properties Gmbh Connection element, wind turbine tower ring segment and method for connecting two wind turbine tower ring segments
US10829945B2 (en) * 2016-04-11 2020-11-10 Tectonic Facades Limited Construction assembly
DE102020121852A1 (en) 2020-08-20 2022-02-24 Fischerwerke Gmbh & Co. Kg Anchor holder, anchor rail and arrangement with the anchor rail

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FI20115154L (en) 2012-08-18

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