Classifications

• • 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 [3D] extent, e.g. lattice girders
  • E04C5/065—Light-weight girders, e.g. with precast parts

Definitions

• the present invention relates to a lattice girder for reinforcing sandwich panels and like structures of concrete, comprising longitudinal wires extending in parallel on different levels, and zigzag wire stirrups interconnecting said longitudinal wires.
• the tensile strength of concrete is low as compared to its compressive strength. Hence, where tensile stress occurs in concrete structures, use is frequently made of steel rods to increase the load capacity of the struc- tures.
• the embracing stirrups are manufactured from steel rods having the desired size and cross-sectional area, by bending.
• the stirrups are mounted to embrace the longitudinal rods and are attached thereto by a thin steel wire (tying wire).
• the purpose of such connection (tying) is to ensure that the reinforcement rods will be correctly positioned in both longitudinal and trans ⁇ verse direction.
• the so-called reinforcement cage thus formed is frequently manufactured separately from the concrete structure and is then positioned in the form and fixed therein.
• a characteristic feature of the tying wire connection is that the wire is not intended to transmit tensile stress in the structure.
• the present invention relates to a lattice girder which can be connected with prefabricated reinforcemen units such as further lattice girders or welded mesh reinforcements, without using a tying wire, thereby to interconnet at the same time a large number of re ⁇ inforcement rods in their correct position so that a coherent unit is formed.
• the separate reinforcement units extend in parallel with the longitudinal rods which they are intended to interconnect.
• the design of the individual reinforcement units facilitates such connection and renders it possible to transmit tensile stress in the finished structure.
• the invention provides for considerable time savi in reinforcement work. Reinforcement cages can be man factured in a fraction of the time required today for tying stirrups to longitudinal rods in conventional manner. Compared to welding of the stirrups to the longi tudinal rods, the connection according to the present invention can be made without large investments in wel equipment.
• connection is made by means of a lattice gir comprising three longitudinal steel rods and two zigz wires, alternatively a lattice girder having two or four longitudinal wires and one zigzag wire which is positioned on one side of the longitudinal wires, or two zigzag wires positioned each on one side of the longitudinal wires so as to be symmetrical for force- absorbing purposes.
• the lattice girder as described can be triangular in shape or extend in one plane.
• the inventive lattice girder is characterised in that the zigzag wires interconnecting the longitudinal wires are formed as loops outside the longitudinal wires. The loops are cut open adjacent the longitudinal wires such that a transverse wire or rod can be inserted into the groove or be positioned in the loop by being turned.
• the lattice girder is attached by means of the loops to welded mesh reinforcements of varying width and shape, or to further reinforcement girders such that the connection is triangular, square or rectangular in section.
• This design provides for a reinforcement which, in concrete structures, is capable of absorbing tensile stress in the concrete and which functions as an embracing reinforcement, the different members forming the connection in the structure. Consequently, large reinforcement structures can be produced with great accuracy and in a very short time.
• the reinforcement structure is rigid and can be transported as a unit, which facilitates handling on the building site. It is further capable of absorbing the torsional stress occurring in concrete structure elements when these elements are lifted or subjected to loads in the final structure.
• Fig. 1 is a perspective view of a lattice girder designed according to the present invention
• Fig. 2 illustrates schematically alternative embodi- ments of the lattice girder
• Figs. 3-5 illustrate schematically various applica ⁇ tions of the lattice girder according to the invention.
• Fig. 1 is a perspective view of a lattice girder comprising three longitudinal wires 1 which are inter ⁇ connected by means of zigzag wire stirrups 2 to form a lattice girder having a triangular section.
• the wire stirrups 2 extend slightly beyond the respective longi ⁇ tudinal wire 1, such that loops 3 are formed outside said wire.
• the loops 3 are cut open adjace the longitudinal wire 1 so as to form a groove 4 into which a transverse wire 5 can be inserted.
• a transverse wire 5 can be inserted.
• the loops 3 of neigh ⁇ bouring stirrups can be cut open in parallel with each other or, as shown to the right, they can be oppositely cut open so that the transverse wire 5 can be inserted into the grooves 4 by being turned.
• the wire 5 may be a single wire interconnecting several lattice girders, or it can be a wire in a mesh reinforcement or some other prefabricated reinforcement unit.
• Fig. 2 shows alternative embodiments of the lattic girder which may thus comprise two or four longitudinal wires 1 and a zigzag wire stirrup 2 extending on one side of the longitudinal wires 1, or between pairs of longitudinal wires, as shown in the upper part of Fig. 2, viz. to the left a cross-section of the lattice gird and to the right a side view thereof.
• the lower part of Fig. 2 illustrates a further variant of the lattice girder with two longitudinal wires 1 and wire stirrups 2 extending on both sides thereof, as shown to the left
• the wire stirrup 2 can be arranged in parallel with each other, as shown in the lower center part of the Figure, or can be relatively offset, as shown in the lower right part of the Figure.
• Figs. 3-5 show how a lattice girder according to one of the embodiments above can be used for reinforcin a structural member of concrete.
• the lattice girders exemplified above can, of cour be modified in different ways.
• the wire stirrups may be extended to form loops merely on one side of the lattice girder.
• not all of the loops need be cut open to form grooves.
• the invention is therefore not limited to the embodiments described above and shown in the drawing, but can be modified within the scope of the appended claims.

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• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Reinforcement Elements For Buildings (AREA)
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• 1987
  • 1987-07-03 SE SE8702756A patent/SE461538B/sv not_active IP Right Cessation
• 1988
  • 1988-07-01 WO PCT/SE1988/000366 patent/WO1989000226A1/en not_active Ceased
  • 1988-07-01 DE DE8888906205T patent/DE3874539T2/de not_active Revoked
  • 1988-07-01 FI FI900008A patent/FI900008L/fi not_active Application Discontinuation
  • 1988-07-01 AT AT88906205T patent/ATE80436T1/de not_active IP Right Cessation
  • 1988-07-01 EP EP88906205A patent/EP0371983B1/de not_active Expired
• 1989
  • 1989-12-21 NO NO895164A patent/NO172505C/no unknown
  • 1989-12-29 DK DK672189A patent/DK164960C/da not_active IP Right Cessation

Non-Patent Citations (1)

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