EP2450497B1 - Reinforced concrete plug and method for producing a concrete-wood compound element - Google Patents

Description

The present invention relates to a method for producing a concrete-wood composite element.

In the construction of new houses, workshops and in the refurbishment of old buildings, there is a high demand for statically perfect connections of wooden beams / wooden frames with concrete elements. Such concrete elements are joined together with the wooden beams / wooden frames to form so-called wood / concrete composite structures and are used, for example, as walls, supporting ceilings or (finished) roof elements. These wood / concrete composite structures have the advantage over pure wood construction that they are still comparatively light despite the proportion of concrete and despite the wood content still have a sufficiently high heat storage mass. Furthermore, such structures significantly improve the acoustic properties of a building and also have a good fire resistance. With the improved soundproofing, they also reduce noticeable vibrations of floors and therefore stiffen the building statically outstanding. Apart from these technical advantages, the visible wooden beams also satisfy the aesthetic wishes of the client.

Various more or less expensive solutions are known for the connection of individual wood / concrete composite elements to these wood / concrete composite structures. One solution, for example, provides for the formation of in-situ concrete bags, which, however, have to be concreted out in situ on a dry construction site, which is otherwise rather free of concrete in timber construction. However, the use of concrete is usually undesirable on such a dry construction site and always associated with a comparatively high outlay. In addition, crossed double-threaded screws are used here. However, these bottom-mounted screws are visible, which may detract from the aesthetic appeal of these composite structures. Basically it is also possible to insert steel parts in the concrete slabs, which must be welded after assembly of the composite elements. However, in wood construction, the risk of fire during welding is relatively high.

Next it is from the German patent application DE 44 20 175 A1 known to aufziessen concrete layers on a beam-like wooden support structure. For the connection of the wooden beams with the concrete layer screw connections of all kinds as well as concrete plugs are used, which are used in holes drilled in the supporting beams. Due to the static non-shiftable relative movement of concrete layer to the wooden beams, however, these fittings and concrete plugs are exposed to high shear forces, which can cause the screw to break and break the concrete plug.

All currently known solutions therefore depends either the flaw that they deliver statically perfect composite structures, but the material and labor required to create these composite structures but high and thus the entire composite structure is relatively expensive or the flaw that the creation of wood-concrete Composite element can be relatively easily achieved, but the static strength can only be achieved with a particularly high use of fittings and concrete plug. Due to the shear forces occurring there is even the danger that the concrete plug can break and the concrete layer then floats freely on the beam, which is usually not acceptable for static reasons.

Based on this prior art, the present invention therefore has the object to solve the problem of connecting wood / concrete composite elements for the creation of wood / concrete composite structures with simpler means and more cost-effective.

1. a) Bereitstellen einer Holztragstruktur, vorzugsweise Holzbalken;
2. b) optionales Bereitstellen einer Schalung für ein mit Beton aufzufüllendes Volumen zur späteren Erstellung einer Betonschicht;
3. c) Bohren von topfartigen Löchern in die Holztragstruktur auf der der späteren Betonschicht zugewendeten Seite;
4. d) Befestigen eines armierten Betonstopfens in dem topfartigen Loch der Holztragstruktur mit einem Überstand des Betonstopfens in das Volumen der zu erstellenden Betonschicht;
5. e) Einbringen von Fliessbeton, ggfs. in die Schalung, und dabei Umgiessen des Überstandes des Betonstopfens; und
6. f) Aushärten des Fliessbetons und ggfs. Entfernen der Schalung.

This object is achieved according to the invention by a method for producing a concrete-wood composite element which comprises the following method step:

1. a) providing a wooden support structure, preferably wooden beams;
2. b) optionally providing a formwork for a volume to be filled with concrete for the later creation of a concrete layer;
3. c) drilling pot-like holes in the wood support structure on the later concrete layer side facing;
4. d) attaching a reinforced concrete plug in the pot-like hole of the wooden support structure with a projection of the concrete plug into the volume of the concrete layer to be created;
5. e) introduction of flow concrete, if necessary into the formwork, while casting over the supernatant of the concrete plug; and
6. f) hardening of the tile and, if necessary, removal of the formwork.

This method produces the desired result of a shear-resistant, ductile composite of the wooden support structure and the flat concrete slab relative to each other.

In an advantageous embodiment of the present invention, the reinforced concrete plug can be designed as a cylindrically shaped metallic cladding tube with a cylinder cavity substantially filling high-strength concrete mass. The reinforced concrete plug should in the present case have a substantially cylindrical shape, wherein the concrete plug may also have a conical or frustoconical shape. Also, a bottle-like bulbous shape is possible. Furthermore, the reinforced concrete plug can also have an annular groove, for example for receiving transverse loads during prefabrication.

In an advantageous embodiment of the method invention, it can be done that the pot-like hole on the hole bottom with a vertical or laterally extending, emerging from the wooden beam Venting channel is equipped. In this way it can be ensured that when filling the hole with fluid concrete no static air pollution extremely reducing air holes remain. Especially in constellations and tasks in which the bottom of the hole is higher than the hole walls, this can be safely avoided such an occurrence of air leaks in the hole.

In an advantageous embodiment, the method can be upgraded to the effect that the cladding tube of the reinforced concrete plug against the concrete mass on one side has a supernatant, wherein in the supernatant slit-like incisions are formed. In this way, the formation of voids at the top of the concrete plug when pouring the concrete element (simultaneous pouring of the concrete plug) can be safely excluded. Alternatively or additionally, the reinforced concrete plug can also be formed such that the cladding tube has a projection over the concrete mass on one side, wherein the supernatant has crescent-shaped recesses for supporting a washer or a screw head. Thus, the concrete plug can be held with an externally mounted screw in the pot hole or on the wooden structure, whereby a mounted in the concrete plug central hole can be avoided. The screw head or the washer then rest on the crescent-shaped recess and thus hold the concrete plug in its position.

• Figur 1 eine schematische Ansicht auf einen armierten Betonstopfen mit Bemassung;
• Figur 2 ein erstes Holz-Beton-Verbundelement mit vor dem Betonieren eingesetzten Betonstopfen nach Figur 1 mit Bemassung;
• Figur 3 eine schematische Ansicht auf einen Ausschnitt aus einem Holzbalken mit in ein Bohrloch eingesetztem Armierungskern;
• Figur 4 ein zweites Holz-Beton-Verbundelement mit vor dem Betonieren eingesetzten Armierungskernen nach Figur 3 mit Bemassung;
• Figur 5 einen armierten Betonstopfen mit Hüllrohr und mit hochfestem Beton aufgefülltem Hohlraum;
• Figur 6 den mit einem Schraubenkopf festgesetzten armierten Betonstopfen gemäss Figur 5; und
• Figur 7 eine Schnittansicht des mit dem Schraubenkopf festgesetzten armierten Betonstopfen gemäss der Figur 6.

Preferred embodiments of the present invention will be explained in more detail with reference to the drawing. Showing:

• FIG. 1 a schematic view of a reinforced concrete plug with dimensioning;
• FIG. 2 a first wood-concrete composite element with in front of Concreting inserted concrete plug after FIG. 1 with dimensioning;
• FIG. 3 a schematic view of a section of a wooden beam with inserted into a borehole Armierungskern;
• FIG. 4 a second wood-concrete composite element with reinforcing cores inserted before concreting FIG. 3 with dimensioning;
• FIG. 5 a reinforced concrete plug with cladding and filled with high-strength concrete cavity;
• FIG. 6 the fixed with a screw head reinforced concrete plug according to FIG. 5 ; and
• FIG. 7 a sectional view of the fixed with the screw head reinforced concrete plug according to FIG. 6 ,

FIG. 1 shows a schematic view of a reinforced cylindrically designed concrete plug 2 and a only slightly changed concrete plug 2 ', both of which has a cylindrically constructed metallic reinforcing core 4 in its interior. This reinforcing core is made of a wire mesh, for example, a grid 10mm x 10mm and a wire thickness of 1 mm identifies. The wire here is a stainless steel; but it could also be designed, for example, as black steel or hot-dip galvanized steel. Depending on the size and stress of the concrete plug 2, the grid can also be chosen to be smaller or larger than shearing forces (eg 16 mm × 16 mm or 25 mm × 25 mm). Likewise, the wire thickness, for example, 1.5 mm or just be chosen according to the static requirements. The reinforcing core 4 is surrounded by a concrete body 6 penetrating it and surrounding it. The concrete body 6 is produced, for example, by the pouring of flowing concrete in a form not shown here. The reinforcing core 4 is thus as Concrete wire cage designed; For example, it can also be configured in multiple layers in the form of a rolled-up wire mesh. The concrete plug 2 has a central, running along the cylinder axis hole 8, in which a screw 10 (as in FIG. 2 shown) can be used and the concrete plug 2 can be mounted on a wooden beam 12. The only slightly modified concrete plug 2 'has an annular groove 7, which can serve for example for receiving transverse loads during prefabrication.

The FIG. 2 now shows a first wood-concrete composite element 14 with concrete plug 2 used before concreting FIG. 1 with dimensioning. To create the wood-concrete composite element 14, the wooden beam 12 is first provided and equipped with the static requirements bill bearing pot holes 16. The pot holes have, for example, a diameter of 70 mm and a depth of 30 mm. For later creation of a concrete layer 18, a formwork (not shown here) may be provided for defining the volume to be filled with concrete. The pot holes 16 are of course on the later concrete layer 18 facing side. By means of the screw 10, a reinforced concrete plug 2 is now fixed in each pot hole 16, wherein the concrete plug 2 protrude from the pot holes 16 and thus protrude into the volume of concrete layer to be created 18. Now more of the flowing concrete can be filled in the vorsehene volume, while also the supernatant of the concrete plug 2, here in this case about 40 mm, fully poured into the concrete layer 18 / embedded. After the curing of the fluidized concrete and the possible removal of the formwork, the wood-concrete composite element 14 is then ready. The reinforced concrete plug 2 create the necessary stability against the occurring shear forces. This approach with the comparatively large concrete plug 2 can thus replace the use of a variety of wood-concrete fittings per concrete plug 2.

The FIG. 3 now shows the starting position at one opposite the Figures 1 and 2 slightly changed procedure. Instead of a prefabricated concrete plug 2 is - as in FIG. 3 shown - initially only the Armierungskern 4 inserted into the pot hole 16 and fixed by means of the screw 10 therein. As in FIG. 4 shown, the flowing concrete is poured to create the concrete layer 18 and the entire armor core 4 is cast around the tile concrete. So that no bubbles remain in the pot hole 16, each pot hole 16 has at the bottom of the hole with a vertically extending, exiting the wooden beam 12 vent passage 20th

FIG. 5 now shows another reinforced concrete plug 22. This concrete plug 22 includes a cylindrical shaped metallic cladding tube 24 and a cylinder cavity substantially filling high-strength concrete mass 26. The cladding tube 24 has a typical dimensioning an outer diameter of 40 to 60 mm and has a wall thickness from 2 to 6 mm.

FIG. 6 now shows a variant 28 of the concrete plug 22. This slightly modified concrete plug 28 can be upgraded to the effect that the cladding tube 24 against the concrete mass 26 on one side a projection 30 (see FIG. 5 ), wherein in the supernatant 30 slit-like incisions 32 are formed. In this way, the formation of voids at the top of the concrete plug 28 when pouring the concrete element (simultaneous pouring of the concrete plug 28) can be safely excluded. In addition, two crescent-shaped recesses 34 for supporting a washer or a screw head 36 in the supernatant 30 has. Thus, the concrete plug 28 can be held with an externally mounted screw 38 in the pot hole or on the wooden structure, whereby a mounted in the concrete plug 28 central hole can be avoided. The screw head 36 and the washer are then on the crescent-shaped recess 34 and thus hold the concrete plug 28 in its position, which in FIG. 7 is shown in the sectional image accordingly.

If, as shown, the head-like wood-concrete composite screws 38 are used and these preferably always on the zero shear point (central axis of the timber beam span) oriented front side of the concrete plug 28 sits, the optionally attached additional screw fuses to prevent lateral twisting of the concrete plug 28 under load , as well as at the same time to avoid any occurring block scissors of the wood between the concrete plug 28, especially at narrower plug intervals.

An important advantage of the cam (concrete plug 28) lies in the fact that where the thrust forces are greatest (just before support on the wall) all screw systems, especially those that are inclined at 45 degrees on one side, on the practical Implementation fail, because basically there is too little space for builders and workers. In general, then there are the screws set vertically with the result that they can absorb only minimal thrust and that just where the greatest forces arrive, so a clear weakening of all inclined Schraubsysteme.Hier shows another advantage of the armored cam / of the reinforced concrete plug, which is indeed introduced vertically from above.

Claims (5)

1. Method for producing a concrete-wood compound element (14) comprising the following process steps:

   a) Providing a wood carrying structure, preferably wooden beam (12);

   b) Optional providing of a lagging for a volume to be filled up with concrete for the later building of a concrete layer (18);

   c) Drilling of pot-like holes (16) in the wood carrying structure on the side turned towards the later concrete layer (18);

   Characterized in that:

   d) Attaching a reinforced concrete plug (2) in the pot-like hole (16) of the wood carrying structure (12) with a projection of the concrete plug (2) in the volume of the concrete layer (18) that is to be built;

   e) Introducing fluid concrete, if applicable in the lagging, and thereby recasting the projection of the concrete plug (2): and

   f) Hardening the fluid concrete and if applicable removing the lagging.
2. Method according to claim 1,
   Characterized in that
   the pot-like hole (16) is equipped on the holey ground with an vertically or laterally conducted air-extractor duct (20) emerging from the wooden beam.
3. Method according to claim 1,
   Characterized in that
   The reinforced concrete plug as a cylindrically formed metallic cladding tube is equipped with high-strength concrete material that essentially fills up the cylinder opening.
4. Method according to claim 3,
   Characterized in that
   The cladding tube, compared to the concrete material, bears a projection on one side, in which slit-like cuts are crimped.
5. Method according to claim 3,
   Characterized in that
   The cladding tube, compared to the concrete material, bears a projection on one side, which comprises crescent-like shaped recesses to support a shim or a screw head.

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