Classifications

• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
  • E04C3/00—Structural elongated elements designed for load-supporting
  • E04C3/02—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces
  • E04C3/12—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of wood, e.g. with reinforcements, with tensioning members
  • E04C3/16—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of wood, e.g. with reinforcements, with tensioning members with apertured web, e.g. trusses
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
  • E04C3/00—Structural elongated elements designed for load-supporting
  • E04C3/02—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces
  • E04C3/12—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of wood, e.g. with reinforcements, with tensioning members
  • E04C3/17—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of wood, e.g. with reinforcements, with tensioning members with non-parallel upper and lower edges, e.g. roof trusses

Definitions

• Wood is a material widely used in construction, and with which it is possible to produce a whole series of load-bearing systems having their own mechanical properties, and making it possible to support all levels and all types of loads.
• the different wooden load-bearing systems are posts and beams, triangulated systems, articulated systems, gantries, beam grids, shells and elements functioning as plates.
• the triangulated system is the most universal, because it allows to take up very large loads, while being very simple to build. As an indication, the triangulated system is causing farm systems used in Europe and which have been developed since the 12th century and are still used today.
• the triangulated wooden systems are to be classified into two main families illustrated schematically in Figures 1 to 6 attached.
• the first system called “parallel frame system”, illustrated by FIGS. 1 to 3, is used for example for bridges or horizontal floor systems.
• Such a system consists of:
• the assembly thus produced rests on at least two supports (5). To reduce internal stresses, it is sometimes possible to add supports inside the system, but this is not always possible.
• the “triangle-shaped” systems, as illustrated by FIGS. 4 to 6, are generally used to make the roof frames and make it possible to give the slope to the latter.
• the elements involved in the realization of such systems consist of one or two rafters (6), a tie (7), diagonals (8) and possibly one or more uprights (9).
• Such assemblies rest on supports (5) disposed at each end of the tie rod (7).
• the invention relates to this technical sector and relates more particularly to the production of a new type of support system both with parallel members and in the shape of a triangle, which, while having high mechanical characteristics, make it possible to reduce the costs of production and is easily adaptable according to the characteristics desired for each particular application (load to be supported, dimensions of the system ).
• the first node in the case of frames, links, tie rods (7), crossbowmen (6) and diagonals (8), is made with solid wood or glued laminated wood pieces, according to the needs of section and the knot is made by means of metal fittings for systems with high inertia, or sometimes even simply glued for floor systems with lower inertia.
• German patent DE 3 910 027 proposes a solution with two-layer dies and a triangulation system with plank or compound diagonals positioned in the core. However, such a solution does not make it possible to strengthen the most stressed nodes.
• this solution has boards in the central layer which are nailed between the two boards of the other members. This nailing tends to cause the central board to crack because the distance from the loaded edge, parallel to the fibers, is too small. This central plank core is therefore of poor performance in terms of its assembly.
• this central core is forced to fill all the space between the external members, since it only has rigidity on one axis, its longitudinal axis.
• This core therefore constitutes a global zone between the external members, and does not allow local reinforcement, adjusted for a single connecting node. It does not allow the optimization of the node, neither in performance (fragility in nailing), nor in economy of material (full area, compared to local area).
• the different beams are produced on the site itself by nailing at least three elementary planks, nailed to each other, and they are characterized in that : - the three elementary boards constituting each beam are of the same thickness;
• the solution according to the invention also makes it possible to reduce the bending moments in the joint since the reinforcement itself absorbs the bending since the “plate” type reinforcement has very high rigidity since it works in both directions of his plan.
• Such a reinforcement makes it possible to take up the shearing forces of the internal beams, such as for example the shearing between a compressed diagonal and a tensioned beam, at the level of the node, by mechanically relieving the external beam as much.
• This reinforcement can be more or less isotropic depending on the forces to be taken up.
• the beams used in the production of a system according to the invention will consist of at least three layers, the reinforcements therefore being positioned at the level of the central layer, which allows double shearing of the through nails by compared to the reinforcement that would be exposed outside the system, as is often the case.
• the two end posts will also consist of three layers nailed together, the central layer not being constituted by a board, but by a wooden structural element of microlame type extending beyond the ends of the two lateral boards as well as towards the inside of the structure in order to form tenons capable of receiving the mortises of the other beams of the system.
• the reinforcement can either be positioned only in the central position, or can be doubled and then being positioned in the layers (two) and (four).
• the structural system according to the invention is characterized in that the number of planks entering into the constitution of each layer is odd and is greater than three, five for example, a reinforcement being positioned at each node in the even layers.
• the ribs or reinforcing plates are arranged at least at the support zones where the forces are maximum. Possibly, the internal forces being lower in the uprights and diagonals, the assemblies of the triangulated system can possibly be carried out conventionally by a simple assembly of the “tenon / mortise” type, the tenon being formed by the offset towards the outside of the board. central, and the mortise by the spacing between two elementary planks constituting the central plank.
• the reinforcement or rib is fixed over its entire perimeter to the other beams (tie rods, crossbowmen, uprights or diagonals) by simple nailing, which is the most economical solution and which has the advantage of being semi- rigid allowing the entire plate to be stressed, after deformation of the edge connectors.
• FIG. 7 is a schematic elevational view of a system with parallel members produced in accordance with the invention.
• FIG. 8 is a detailed exploded perspective view of the circled area of Figure 7 showing the production of the assembly nodes at the support;
• FIG. 9 is a schematic perspective view showing a frame produced according to the invention with nailing of the various elements together;
• FIG. 10 is an exploded view, in perspective, of the realization of the nodes at the end support area and the central upright with the tie and the diagonal of the frame.
• the elementary planks used in the constitution of each beam are solid planks whose cross section is generally between 10 and 30 cm in width for 3 to 8 cm in thickness.
• planks For structures that can represent a very high resistance, individual planks can be recomposed into larger sections.
• the length of said boards can be variable and depends on the systems to be produced and will for example be between four to eight meters.
• the concrete examples of embodiment which follow will allow a better understanding of the invention.
• each beam consists of three elementary planks (10,11,12 ).
• the intermediate board (10) is offset with respect to the ends of the side boards (11,12), and this, in this case, by a distance of approximately 50 cm thus allowing to provide at each end a recess forming a mortise (13).
• the diagonals (4) are produced in a similar manner from three boards and also have a mortise at their end.
• the internal uprights (M) are made in a similar way.
• the post (3) is, in turn, made up of two external planks (14) between which is inserted, over its entire length, a third plank (15), intended to constitute the panel-type reinforcement positioned in the core and which is formed of a microlame type structural panel having a thickness of 4 cm, the external boards (14) also having a thickness of 4 cm.
• This panel (15) projects at each end with respect to the side boards (14,15) and forms a tenon having a height of 20 cm therefore corresponding to the width of the boards (10,11,12) constituting the dies, and a length 50 cm corresponding to the length of the mortise (13) provided at the ends of the beams constituting the dies.
• the reinforcement plate (15) extends over the entire surface of the system at each end at the level of the supports (5), it could possibly be envisaged to produce reinforcement plates only at each end , the central part of the post (3) then being constituted by an additional board, set back from the ends of the side boards.
• connection is also carried out by inserting, at the level of the junction zones, additional plates.
• Each of the elements therefore comprises at the junction zone a mortise intended to receive the reinforcing element.
• the assembly could be carried out without reinforcing element and the ends of the uprights (M) and diagonals (4) will have the shape of a tenon formed by the offset towards the outside of the central board while the dies or members (1,2) will include, along their length, mortises obtained by making the internal plank (10) by means of elementary planks spaced from each other by a length corresponding to the tenon of the ends.
• FIGS. 9 and 10 Such an embodiment according to the invention is illustrated in FIGS. 9 and 10 and corresponds to the general structure which is the subject of FIG. 4, it being understood that structures of the type could be produced in a similar manner illustrated by figures 5 and 6.
• This structure is also made from boards having a section of 20 cm x 4 cm.
• the central plate (21) is, at the ends, set back relative to the ends of the side boards, so as to form at this level a mortise (24) capable of receiving a reinforcing element.
• the reinforcement insert (20) is of triangular shape, the base of which has a length of 700 mm and a height of 400 mm. .
• mortises are provided at each end of the diagonals (8) and uprights (9), and this by shifting the layer internal with respect to the ends of the side planks, the mortise in the tie rod (7) being, for its part, obtained by producing the central plank from elementary planks spaced from one another.
• connection between the various constituents is obtained by nailing and the reinforcements (20) of the nodes, the junction of which is produced from a panel constituted by a wooden structural element of microlame type having a thickness of 4 cm.
• each beam makes it possible to increase the surface of the nailing zones reinforcing the structure.
• Such an interface panel also regulates the bending moments in the articulation on the dies in the case of a system with parallel or triangulated members since the reinforcement itself absorbs bending; it thus absorbs the shear between the internal beams arriving in the node by mechanically relieving the external beam.

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Citations (5)

Family Cites Families (3)

• 1998
  • 1998-12-03 FR FR9815456A patent/FR2786796B1/fr not_active Expired - Fee Related
• 1999
  • 1999-10-28 DE DE69911055T patent/DE69911055T2/de not_active Expired - Fee Related
  • 1999-10-28 AT AT99950859T patent/ATE248965T1/de not_active IP Right Cessation
  • 1999-10-28 WO PCT/FR1999/002627 patent/WO2000032891A1/fr active IP Right Grant
  • 1999-10-28 EP EP99950859A patent/EP1135565B1/de not_active Expired - Lifetime
  • 1999-10-28 AU AU37910/00A patent/AU3791000A/en not_active Abandoned
  • 1999-10-28 JP JP2000585512A patent/JP2002531731A/ja not_active Withdrawn
  • 1999-10-28 BR BR9915894-9A patent/BR9915894A/pt active Search and Examination
• 2001
  • 2001-05-25 US US09/866,432 patent/US20020124521A1/en not_active Abandoned

Patent Citations (5)

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