Semi-finished part, wood-concrete composite construction element, use and method

Abstract

The invention relates to a semi-finished product (104, 204, 404) for the production of a wood-concrete composite building element (100, 200, 400) with a stacking arrangement (106) comprising several bottom chord elements (108, 109) made of wood and several web elements (110, 310), wherein the several bottom chord elements (108, 109) and the several web elements (110, 310) are arranged side by side in a stacking direction (112) and glued together, so that the bottom chord elements (108, 109) and the web elements (110, 310) together form a bottom (114) and an opposite top (116) of the stacking arrangement (112), wherein the web elements (110, 310) project areas (122) on the top (116) beyond the bottom chord elements (108, 109) to whose at least partial embedding in concrete, wherein the several bottom chord elements (108, 109) and the several web elements (110, 310) are arranged alternately next to each other in the stacking direction (112) and wherein the web elements (110,310) are made of wood-based material. The invention further relates to the use of the semi-finished part (104, 204, 404) as well as a wood-concrete composite building element (100, 200, 400) and a method for its production.

Description

[0001] The present invention relates to a semi-finished component for the production of a timber-concrete composite element, in particular a timber-concrete composite slab or a timber-concrete composite precast element. The present invention further relates to a timber-concrete composite element, in particular a timber-concrete composite slab or a timber-concrete composite precast element. The present invention further relates to a use of the semi-finished component for the production of a timber-concrete composite element. The present invention further relates to a method for the production of a timber-concrete composite element.

[0002] Composite timber-concrete slabs are a known technology. However, their construction is more complex and therefore more expensive than that of concrete slabs. Key cost drivers include the measures required to bond the timber to the concrete. Furthermore, existing systems do not optimally utilize the mechanical properties of their components and their interaction.

[0003] EP 1 582 644 discloses a timber-concrete composite slab in which the bond between timber and concrete is achieved by notches in the timber combined with screws connecting the timber and concrete. The use of screws involves considerable labor and material costs. Furthermore, the notches reduce the cross-sectional area, necessitating greater overall thicknesses to meet structural requirements. EP 0 528 450 discloses a timber-concrete composite slab in which the bond between timber and concrete is achieved using timber-concrete composite screws, which involves even greater labor costs. Systems with bonded expanded metal or other mechanical fasteners are also known, which likewise result in complex manufacturing and / or assembly processes.

[0004] EP 0 952 271 discloses a wood-concrete composite element comprising a timber component made of numerous boards joined together in a cross-laminated timber (CLT) construction and a concrete component. Composite webs made of solid wood are inserted between several boards of the timber component. These webs serve to embed the timber component within the concrete component. However, solid wood has only moderate transverse tensile strength and also natural weaknesses, such as knots, which can lead to cracking of the composite web and thus to failure of the bond between the concrete and wood, and consequently of the entire component. According to EP 0 952 271, composite sheets or composite webs made of plastic, steel mesh, or woven fabric can also be used instead of solid wood composite webs. These can be attached to the CLT, for example, by gluing or screwing.However, this leads to more complex manufacturing due to the diverse and costly materials, especially when it comes to bonding them together.

[0005] From EP 1 992 755, a timber-concrete composite component is further disclosed, comprising a compression flange made of concrete and one or more tension flanges made of wood-based material or timber. The one or more tension flanges have recesses facing the compression flange, into which webs are inserted, connecting the tension flanges to the concrete compression flange. These recesses reduce the cross-sectional area and thus weaken the tension flanges.

[0006] Against this background, the present invention aims to provide a wood-concrete composite building element and a semi-finished product for its manufacture, which at least partially reduces or avoids the disadvantages described above.

[0007] This problem is solved according to the invention by a semi-finished product for the production of a timber-concrete composite element, in particular a timber-concrete composite slab or a timber-concrete composite precast element, with a stacking arrangement comprising several bottom chord elements made of wood and several web elements, wherein the several bottom chord elements and the several web elements are arranged side by side in a stacking direction and bonded together, so that the bottom chord elements and web elements together form a bottom and an opposite top of the stacking arrangement, wherein the web elements have areas projecting beyond the bottom chord elements on the top side for their at least partial embedding in concrete, wherein the several bottom chord elements and the several web elements are arranged alternately side by side in the stacking direction and wherein the web elements are made of wood-based material.

[0008] Solid wood is a highly inhomogeneous material, exhibiting significant inhomogeneities in cross-section, particularly due to knots or irregular grain patterns. Compared to web elements made of solid wood, web elements made of engineered wood have more consistent properties, thus reducing the risk of failure of the wood-concrete composite element produced with the precast element due to inherent weaknesses in solid wood, such as knots.

[0009] Engineered wood products also have the advantage of better resource utilization compared to solid wood. For example, a larger proportion of the original wood can be used in the production of engineered wood products than when cutting solid wood.

[0010] Furthermore, engineered wood products can be manufactured from lower-grade and recycled wood, exhibiting the same or even higher load-bearing capacity as higher-grade solid wood. In particular, engineered wood web elements can demonstrate significantly higher tensile strength in the panel direction (i.e., in the longitudinal direction) and in the vertical direction (i.e., from the bottom to the top of the stacked semi-finished product) than the transverse tensile strength of solid wood. This allows for resource conservation and more cost-effective production of the semi-finished product.

[0011] Furthermore, a surprising advantage arises from the alternating arrangement and bonding of web elements made of wood-based material and bottom chord elements made of wood: When a bottom chord element made of solid wood is subjected to tensile stress, homogeneous, fiber-parallel stresses occur in homogeneous areas of the solid wood with parallel grain direction across the entire cross-section. However, in areas of inhomogeneity, such as knots or inhomogeneous grain patterns, significant deviations and deflections of the stress distribution occur, since knots, for example, exhibit only a fraction of the strength and stiffness of the undisturbed wood grain. Consequently, the stresses increase due to redirection into the remaining cross-section of the bottom chord element, and this redirection, combined with oblique grain patterns, results in stresses perpendicular to the otherwise normal grain direction of the wood.This can lead to premature failure of the bottom chord element, as the wood initially cracks in the knot area when the load increases, and the loads from this area are redistributed into the remaining cross-section. This redistribution then results in high local transverse tensile stresses as well as additional bending stresses from deformation in the cracked wood cross-section, causing the wood to crack perpendicular to the grain. The crack then propagates along the grain, leading very rapidly to the overall failure of the wood cross-section.

[0012] It was found that such premature failure of the bottom chord element can be prevented by alternating the arrangement of glued web elements made of wood-based material and bottom chord elements made of wood.

[0013] Due to the more homogeneous properties of the wood-based material, the web elements exhibit quite high strength even perpendicular to the grain of the wood.

[0014] Bottom chord elements are used. The bonding of the bottom chord elements to adjacent web elements on both sides prevents local tearing of the bottom chord elements perpendicular to the grain in areas of inhomogeneity, such as knots, and also prevents bending of the bottom chord elements at such inhomogeneities in the event of failure. In particular, the load in the bottom chord element can be distributed more effectively across the remaining cross-section via the bonded web elements, and the low transverse tensile strength of the solid wood is compensated for by the high strength of the engineered wood used in the web elements. This leads to a significant increase in load-bearing capacity, allowing the bottom chord elements and, if applicable, web elements to be dimensioned smaller and therefore more cost-effectively. With web elements made of solid wood, this effect would not occur, or would only occur to a significantly reduced extent, due to the low transverse tensile strength of solid wood.

[0015] The precast element is intended for the production of a timber-concrete composite structure. This timber-concrete composite structure could, in particular, be a timber-concrete composite slab. For this purpose, one or more precast elements can be positioned and joined with cast-in-place concrete to form a timber-concrete composite structure, especially a timber-concrete composite slab. It is also conceivable that the precast element is used to produce a precast timber-concrete composite element, which is then positioned and, for example, grouted with concrete around its edges.

[0016] The semi-finished product features a stacking arrangement comprising several bottom chord elements made of wood and several web elements. The bottom chord elements and web elements extend, in particular, in a longitudinal direction that runs transversely to the stacking direction. The bottom chord elements and web elements extend, in particular, parallel to each other in their longitudinal direction. The bottom chord elements can, in particular, be in the form of boards or squared timber. Preferably, the bottom chord elements have a rectangular cross-section transverse to their longitudinal direction.

[0017] The stacking arrangement can, for example, have a width in the stacking direction in the range of 0.5–2.5 m, preferably 0.75–2 m, and in particular 1–1.5 m. The stacking arrangement can, for example, have a length in the longitudinal direction (span) in the range of 1–15 m, preferably 2.5–10 m, and in particular 5–8.5 m.

[0018] The bottom chord elements are made of wood, in particular solid wood. The bottom chord elements can, in particular in the longitudinal direction, have several connected, in particular finger-jointed, solid wood sections.

[0019] The bottom chord elements, in combination with the webs arranged between them, serve as tension chords to absorb tensile forces in the finished timber-concrete composite element. The sections of the webs that project beyond the bottom chord act as spacers between the bottom chord and the concrete top chord in the finished timber-concrete composite element, connecting the precast element to a layer of concrete. For this purpose, the webs have sections on their upper surface that project beyond the bottom chord elements, allowing for at least partial embedding in the concrete.

[0020] The multiple bottom chord elements and the multiple web elements are arranged alternately side by side in a stacking direction and connected to each other, so that the bottom chord elements and web elements together form a bottom and an opposite top of the stacked arrangement. The bottom and the top are therefore formed by the respective surfaces of the alternately arranged bottom chord elements and web elements.

[0021] The alternating arrangement of the bottom chord elements and web elements means that each bottom chord element is bonded to web elements on both sides, which – as described above – allows for a more even distribution of tensile forces and a limitation of crack lengths.

[0022] The top side is the side of the stacked arrangement that faces the concrete layer in the finished timber-concrete composite element. On this top side, the web elements project beyond the bottom chord elements and thus, in the finished timber-concrete composite element, can serve as spacers between the bottom chord elements and the concrete layer. Furthermore, by at least partially embedding the projecting areas in the concrete layer, they connect the stacked arrangement to the concrete layer.

[0023] The underside of the stacked arrangement is preferably essentially flat. In this way, for example, a flat underside can be achieved for a timber-concrete composite slab manufactured from the precast element.

[0024] The alternating arrangement of the bottom chord elements and web elements fully integrates the web elements into the stacking arrangement without weakening the cross-section of the bottom chord elements. This results in a statically very efficient cross-section for the bottom chord elements without any weakening.

[0025] The alternating bottom chord elements and web elements are bonded together. The bond between the bottom chord elements and the adjacent web elements is preferably substantially full-surface. This prevents the bottom chord elements from splitting perpendicular to the grain. Without such bonding, solid wood can split on one side under high loads, particularly in areas of weakness, such as from a knot. Due to the low transverse tensile strength and the typical diagonal grain of solid wood, such a crack propagates through the wood, potentially leading to total failure. Bonding the bottom chord elements to the web elements prevents this mechanism and increases the load-bearing capacity of the bottom chord elements. In particular, bonding the bottom chord elements to the web elements inhibits crack propagation and thus limits crack lengths.

[0026] Furthermore, the adhesive bonding can optimize the swelling properties of the stacked arrangement in the presence of moisture, since the different swelling properties of the bottom chord elements and web element partially block each other, and the adhesive bonding also acts as a moisture barrier.

[0027] In addition, the bottom chord elements and adjacent web elements can also be connected to each other in a form-fit and / or force-fit manner, for example by being screwed or nailed together, for example by means of steel nails or hardwood nails.

[0028] The web elements are made of wood-based material. The wood-based material is, in particular, a panel material. Preferably, the wood-based material of the web elements contains wood chips.

[0029] The wood-based material preferably contains wood particles, for example wood chips or wood fibers, and a binder, for example a resin, in particular a synthetic resin such as melamine resin. In particular, the web elements can be made of particleboard, especially particleboard P5 or P7 according to EN 712, of OSB (Oriented Strand Board), especially OSB / 3 or OSB / 4 according to EN 300, or of flakeboard. Preferably, the wood-based material consists of at least 50 wt.%, and more preferably at least 80 wt.%, of wood particles. Furthermore, the wood-based material preferably contains a binder with a content in the range of 2–12 wt.%.

[0030] The wood-based material can also be a panel material composed of veneer layers, in particular plywood or laminated veneer lumber (LVL).

[0031] The wood fibers of the engineered wood product, particularly in OSB or plywood, are preferably oriented in at least two principal directions of the web elements, especially in the longitudinal direction and the vertical direction, i.e., from the underside to the top of the stacked arrangement. Alternatively, the wood fibers of the engineered wood product, particularly in particleboard or fiberboard, can be oriented randomly. This fiber orientation results in such materials exhibiting higher shear strength, shear stiffness, and transverse tensile strength compared to natural wood. In this way, a more shear-resistant and durable connection between the bottom chord elements and the concrete layer can be achieved via the web elements.

[0032] The aforementioned problem is further solved according to the invention by a timber-concrete composite element comprising the previously described precast element or an embodiment thereof and a concrete layer, wherein the projecting areas of the web elements are embedded, in particular cast, at least partially into the concrete layer. The precast element, in particular its bottom flange elements, and the concrete layer are connected to each other, in particular in a shear-resistant manner, by the projecting areas of the web elements of the precast element being embedded, at least partially, in the concrete layer.

[0033] The timber-concrete composite element can be, in particular, a timber-concrete composite slab. The concrete layer can be produced using cast-in-place concrete. Alternatively, the timber-concrete composite element can be a precast timber-concrete composite element, especially a slab element, which is provided with a concrete layer during manufacturing before being transported to the installation site.

[0034] The timber-concrete composite element has a concrete layer. This concrete layer can consist of normal-weight concrete, particularly with compressive strength classes C20 / 25 to C30 / 37. If required, concrete with a higher strength class can also be selected. Alternatively, the concrete layer can be made of steel fiber reinforced concrete. Preferably, a low-shrinkage concrete mix is ​​used for the production of the concrete layer. The concrete layer preferably has a thickness in the range of 20–150 mm, more preferably 40–100 mm, and more particularly 50–80 mm. This achieves a good compromise between weight and load-bearing capacity in combination with the precast element. The concrete layer, or the concrete mix used for its production, preferably has a maximum aggregate size of < 30 mm, more preferably < 25 mm, and more particularly ≤ 16 mm.

[0035] Reinforcement can be embedded in the concrete layer. This helps to limit the crack widths in the concrete layer. The reinforcement can, in particular, comprise a reinforcing steel mesh or individual reinforcing bars. Preferably, the reinforcement extends beyond the concrete layer in the longitudinal direction. This allows the timber-concrete composite element to be embedded longitudinally in cast-in-place concrete, for example, in a ring beam.

[0036] The aforementioned problem is further solved according to the invention by using the previously described semi-finished product or an embodiment thereof for the production of a timber-concrete composite element, in particular the previously described timber-concrete composite element or an embodiment thereof. In particular, during the production of the timber-concrete composite element, the protruding areas of the web elements are partially embedded in concrete.

[0037] The aforementioned problem is further solved according to the invention by a method for producing the previously described wood-concrete composite element or an embodiment thereof. In the method, the previously described semi-finished element or an embodiment thereof is provided. Furthermore, in the method, at least an upper part of the projecting areas of the web elements of the semi-finished element is embedded in uncured concrete, so that when the concrete cures, a concrete layer is formed in which at least the upper part of the projecting areas of the web elements is embedded.

[0038] In this process, a filler material and / or one or more installation lines and / or conduits can optionally be arranged between the protruding sections. The installation lines and / or conduits can run, for example, in the stacking direction and / or longitudinally. The arrangement of the filler material or the one or more installation lines or conduits can take place before or after embedding at least the upper part of the protruding sections of the web elements of the precast element in uncured concrete.

[0039] In one embodiment of the process, the precast element is positioned with the protruding sections of the web elements facing upwards, and the uncured concrete is applied to the timber-concrete composite element. In this embodiment, any filler material is preferably placed between the protruding sections before the concrete is applied. In this way, the filler material can act as a spacer between the bottom chord elements and the concrete.

[0040] The prefabricated element can be positioned on-site, for example, on one or more supports, particularly the walls of a building. Alternatively, the concrete can be poured in place. In this way, a timber-concrete composite slab can be constructed on-site.

[0041] However, it is also conceivable that the wood-concrete composite element is manufactured as a prefabricated wood-concrete composite element, which is then transported to its place of use.

[0042] In an alternative embodiment of the process, the precast element is oriented with the protruding web sections facing downwards and immersed, at least in the upper part of these sections, in uncured concrete. This allows the distance between the bottom chord elements and the concrete layer to be adjusted by varying the immersion depth of the web sections in the uncured concrete, independent of any filler material between the protruding sections. This embodiment thus enables the production of timber-concrete composite elements without filler material between the protruding sections, or the subsequent insertion of filler material between the protruding sections. This embodiment is particularly advantageous for the production of timber-concrete composite precast elements.

[0043] The following describes various embodiments of the semi-finished product, the timber-concrete composite element, the method, and its use, with each embodiment applying independently to the semi-finished product, the timber-concrete composite element, the method, and its use. Furthermore, the individual embodiments can be combined with one another as desired.

[0044] In one embodiment, the bottom chord elements are made of solid structural timber. This material is particularly advantageous for the tension chord function of the bottom chord elements in the timber-concrete composite component.

[0045] The bottom chord elements can be designed as a single piece of solid wood extending along the longitudinal direction, covering essentially the entire length of the stacking arrangement. Alternatively, the bottom chord elements may consist of several solid wood pieces joined along the longitudinal direction by means of tension-transmitting longitudinal joints, such as finger joints or scarf joints.

[0046] The solid wood of the bottom chord elements preferably has a strength class in the range C14 to C30, more preferably C16 to C24, according to EN 338:2016 or an equivalent grading class.

[0047] In one embodiment, the bottom chord elements have a width in the stacking direction of 40–200 mm, preferably 60–150 mm, and particularly 75–120 mm. The use of relatively narrow bottom chord elements between each pair of web elements ensures that stresses occurring in the bottom chord elements are distributed more evenly across the web elements to which they are bonded. In particular, transverse forces occurring at a natural weak point of a bottom chord element, for example, due to a branch, can be transferred via the web elements located near the narrow bottom chord elements. Furthermore, the lengths of any cracks that may occur in the bottom chord elements are limited by the nearby web elements.

[0048] In particular, the closely spaced web elements in the stacking direction create a strong bond between the bottom chord elements and the concrete layer. The preferably full-surface bonding of the web elements and bottom chord elements achieves a close spacing of the adhesive layers in the stacking direction, further strengthening the bond and, in particular, preventing the bottom chord elements from cracking perpendicular to the grain. This increases the load-bearing capacity of the timber-concrete composite element produced with the precast component.

[0049] In one embodiment, the bottom chord elements have a height in the range of 40–160 mm, preferably 50–100 mm, and particularly 50–70 mm. The height of the bottom chord elements is, in particular, transverse to the stacking direction, running from the underside to the top of the stacked arrangement. It has been found that with the proposed prefabricated component, good load-bearing capacities of the resulting timber-concrete composite element can be achieved with relatively small cross-sections of the bottom chord elements. In this way, the prefabricated components can be manufactured with less material and thus more cost-effectively.

[0050] In one embodiment, the web elements have a width in the stacking direction of 10–25 mm, preferably 12–20 mm, and particularly 14–18 mm. It has been found that these web element widths are sufficient for securely connecting the bottom chord elements to the concrete layer when using web elements made of wood-based material. Furthermore, these relatively small widths ensure that the bottom chord elements constitute a larger relative proportion of the stacked arrangement, thereby improving the load-bearing capacity of the precast wood-concrete composite element. In particular, the wood of the bottom chord elements has a significantly higher modulus of elasticity, for example, three times higher, than the wood-based material of the web elements, such as OSB. The larger proportion of the bottom chord elements in the total bottom chord thus results in greater longitudinal stiffness.The relatively narrow widths of the web elements described above are particularly advantageous in combination with the previously described narrow widths of the bottom chord elements. The combination of the specified width ranges simultaneously achieves good stress distribution and crack length limitation, as well as high longitudinal stiffness.

[0051] The dimensions of the bottom chord elements, in particular their height, and / or the dimensions of other load-bearing parts can be adapted to the desired load-bearing capacity and span, i.e., length of the semi-finished part in the longitudinal direction.

[0052] In one embodiment, the areas of the web elements projecting beyond the bottom chord elements on the upper side have a height in the range of 20–600 mm, preferably 50–600 mm, more preferably 200–500 mm, and particularly 250–400 mm. In other words, the web elements preferably project 20–600 mm, more preferably 50–600 mm, and more preferably 200–500 mm, and particularly 200–400 mm, beyond the bottom chord elements on the upper side. In this way, sufficiently deep embedding in the concrete can be achieved during the manufacture of the timber-concrete composite component. Furthermore, the concrete layer can be spaced apart from the bottom chord elements, allowing the concrete layer and the bottom chord elements to be positioned outside the neutral axis, resulting in improved load-bearing properties of the timber-concrete composite component or enabling a reduction in material thickness for the same load-bearing capacity.

[0053] In one embodiment, the projecting areas of the web elements are provided with a profile, particularly in the upper part of the projecting areas. Specifically, the web elements can have a profiled web edge. In this way, a shear-resistant connection in the longitudinal direction can be achieved between the bottom chord elements and the concrete layer of the timber-concrete composite element to be produced with the precast element. In particular, a positive fit between the web elements and the concrete layer can be achieved in this way, so that the stacked arrangement and the concrete layer are load-bearingly connected. Furthermore, such a profile can be easily incorporated into the web elements.

[0054] The profiling can be such, for example, that the web elements have recesses at their edges, particularly in the form of a cam profile. The concrete poured into the recesses creates a positive fit, especially in the longitudinal direction. The recesses preferably have a depth (or the cams between them a height) in the range of 5–80 mm, more preferably 10–40 mm, and particularly 15–25 mm. This ensures that the resulting positive connection between the concrete layer and the web elements can effectively absorb tensile forces in the longitudinal direction.

[0055] The recesses can be rectangular. A rectangular shape is easy to produce and provides good absorption of tensile forces in the longitudinal direction. Tensile forces perpendicular to the concrete surface are absorbed to a limited extent by friction and interlocking of the concrete against the vertical sides of the rectangular recesses. For better absorption of such tensile forces, the depth of the recesses in this case is preferably at least 10 mm, and more preferably at least 15 mm.

[0056] Preferably, one or more of the recesses have a dovetail shape, which improves the embedding in the concrete and allows tensile forces occurring perpendicular to the concrete surface, i.e. in the vertical direction of the web elements, to be absorbed more effectively.

[0057] However, the inclined flanks of a dovetail shape can cause a force acting along the longitudinal direction to be partially redirected into a vertical force in the height direction of the web element, which results in a transverse tensile stress, particularly in the shear-stressed cross-section of the cam between the recesses.

[0058] In a further embodiment, one or more of the recesses have a rectangular shape with one or more undercuts. The one or more undercuts preferably each have an undercut surface that particularly preferably runs parallel to the upper surface of the web edge. In particular, the recess can have one or more undercuts on both sides. As with the dovetail shape, the undercuts achieve better embedding in the concrete, enabling it to better absorb tensile forces acting transversely to the concrete surface. However, compared to a dovetail shape, the rectangular shape with one or more undercuts does not, or only to a minimal extent, cause a redirection of a longitudinal force into a vertical force, thus reducing tensile stresses in this direction as well as transverse tensile stresses in the area of ​​the cams.

[0059] In a further embodiment, one or more of the recesses have a one-sided dovetail shape with a vertical and an inclined flank. Depending on the position of a recess in the longitudinal direction, shear forces in the longitudinal direction may occur only in one direction or be significantly stronger in one direction than in the opposite direction. The vertical flank of the recess is preferably oriented so that it is subjected to a greater load from the shear forces than the inclined flank. In this way, the deflection of the shear force into a vertical force and consequently the occurrence of transverse forces can be reduced compared to a dovetail shape with two sides, while the inclined flank ensures good embedding in the concrete with a vertical interlock.

[0060] In particular, one or more of the recesses can be arranged along the longitudinal direction such that the inclined flank of a recess is closer to the center of the web element in its longitudinal direction than the vertical flank. In other words, the vertical flank of the cams located between the recesses is preferably closer to the center of the web element in its longitudinal direction than the inclined flank.

[0061] The recesses or the cams positioned between them can vary in size and shape along their longitudinal direction. Furthermore, curved, polygonal, or other profiles can be used that ensure sufficient interlocking with the concrete.

[0062] In one embodiment, a plate is provided on the underside of the stacking arrangement, which is preferably bonded to the underside. The plate preferably extends substantially over the entire underside of the stacking arrangement. Several plates arranged side by side are also conceivable, which together extend over the entire underside of the stacking arrangement. The one or more plates preferably extend in the stacking direction over several bottom chord elements and / or several web elements, preferably substantially over the entire extent of the stacking arrangement in the stacking direction.

[0063] The plate can reduce swelling and / or shrinkage of the stack arrangement in the stacking direction.

[0064] Unidirectionally glued wood components are prone to swelling and shrinkage perpendicular to the grain. This can amount to approximately 10 mm per meter of cross-sectional width with a 4% change in wood moisture content. When using such prefabricated components for wood-concrete composite elements, this directional swelling and shrinkage can lead to problems when the building's moisture content changes, for example, due to changes in use or the transition between the heating and summer seasons. To mitigate these problems, wide construction joints can be incorporated between the components. However, these joints can, in turn, lead to aesthetic or structural physics issues, such as airtightness, moisture transport, or sound insulation, or require complex design considerations. Furthermore, the practically non-swelling and non-shrinking nature of concrete in such components makes them susceptible to undesirable deformations.By using a plate preferably glued to the underside, such dimensional changes can be reduced to approximately 10% - 20% compared to dimensional changes without such a plate, thus facilitating the use of the semi-finished products or wood-concrete composite building elements.

[0065] The panel is preferably a wood-based panel, for example an OSB panel or particleboard. An OSB panel is preferred because it can particularly well absorb forces and stresses from the stacking arrangement.

[0066] The panel can be decorated on the side facing away from the stacking arrangement, for example, with a decorative print. This eliminates the need for subsequent work to decorate the underside of a wood-concrete composite ceiling produced with the semi-finished element.

[0067] The board may be coated, particularly with resin, for example melamine. For instance, the board could be a melamine-coated particleboard. The board may also have a fire-retardant coating to improve the fire protection of the prefabricated element or the wood-concrete composite component.

[0068] Instead of or in addition to a wood-based panel, a plasterboard, in particular a gypsum building board or gypsum fire protection board, or a gypsum fiberboard (for example a Fermacell gypsum fiberboard, available from James Hardie plc, Dublin, Ireland) can also be used as the panel.

[0069] Optionally, a fire-resistant panel can be used, for example, a fire-resistant OSB panel. Fire protection can be further improved by additionally or alternatively using a panel with a thickness of at least 20 mm.

[0070] In one embodiment, the bottom chord elements and the concrete layer lie directly on top of each other. In another embodiment, a gap is provided between the bottom chord elements and the concrete layer. Accordingly, preferably only an upper part of the projecting areas of the web elements is embedded in concrete. The unembedded part of the projecting areas defines the distance between the bottom chord elements and the concrete layer. The gap is arranged accordingly between the unembedded parts of the projecting areas.

[0071] In this way, a system analogous to I-beams is created, in which the top chord (compression chord) formed by the concrete layer and the bottom chord (tension chord) formed by the stacking arrangement or the bottom chord elements are formed by materials that are particularly advantageous for this purpose, namely the compression chord made of concrete and the bottom chord made of wood or wood-based material, whereby the spreading of the compression and tension chords as well as the transmission of the shear forces necessary for the load-bearing effect is carried out by the shear-stiff web elements made of wood-based material.

[0072] The gap created between the bottom chord elements and the concrete layer enables a structurally very efficient and material-saving overall design of the timber-concrete composite element. This design exhibits a significantly higher moment of inertia compared to timber-concrete composite elements where the timber bottom chord and concrete top chord are arranged directly above one another, particularly compared to cross-laminated timber (CLT) with a concrete layer poured on top, which is frequently used in timber-concrete composite elements. Specifically, the gap ensures that less load-bearing material, particularly only the web elements, is located in and near the neutral axis.

[0073] The space between the chords can be essentially empty, for example filled with air. This creates a cavity between the bottom chord elements and the concrete layer, through which, for example, one or more installation lines, such as power and / or data lines or utility lines like water and / or gas lines, and / or one or more conduits for them can be laid, for example in the stacking direction and / or longitudinally.

[0074] In one embodiment, a filler material is arranged in the space, particularly in the form of a layer of filler material interrupted, especially by the web elements in the stacking direction. The filler material can occupy the entire space. However, it is also conceivable that the filler material occupies only a portion of the space. Preferably, the filler material forms a layer with a thickness of at least 20 mm, more preferably at least 50 mm.

[0075] In a corresponding embodiment, particularly of the precast element, a filler material, especially in the form of a filler layer, is arranged between the projecting areas of the web elements. Specifically, the bottom chord elements and the web elements form channels on the top side of the stacked assembly in which the filler material can be arranged. The filler material is arranged between the bottom chords and a layer of concrete to be cast with the precast element during the production of a timber-concrete composite component. In the precast element, the filler material is preferably arranged such that an upper part of the projecting areas of the web elements extends beyond the filler material on the top side for embedding in a concrete layer.

[0076] The filler material can serve as a spacer, particularly a spacer layer, for pouring the concrete layer. Furthermore, the filler material can influence the properties of the timber-concrete composite component, especially its thermal and / or acoustic insulation properties. Accordingly, the filler material can be an insulating material, specifically a sound-insulating and / or thermal insulation filler.

[0077] When using the semi-finished component or wood-concrete composite element for insulated top floor ceilings or flat roofs, the construction height can be reduced, for example, by using a thermally insulating filling material, as the roof insulation can be made thinner or even omitted entirely.

[0078] For example, the insulation material can be fibrous material, such as one or more of the following fiber materials: mineral fibers, such as glass fibers (for example as glass wool) or rock fibers (for example as rock wool), or organic fibers, such as wood fibers or cellulose fibers.

[0079] Furthermore, the insulation material can be a foaming material, for example mineral foam (e.g. Geolyth mineral foam, available from GEOLYTH Mineral Technologie GmbH, 4407 Dietach, Austria) or polymer foam, for example polyurethane foam (PUR foam).

[0080] The insulation material can be in the form of insulation mats, for example made of fibrous or foam material. Particularly with organic fibers such as wood fibers or cellulose fibers, the insulation material can also be blown into the cavity.

[0081] Furthermore, the filling material can be bulk material, for example one or more of the following: sand, gravel, crushed stone, recycled material such as construction waste, expanded clay, wood particles, especially wood particles impregnated with cement paste. This allows the mass of the wood-concrete composite component and thus its sound insulation properties to be increased.

[0082] The bulk material can be bound by a suitable binder, such as cement or polyurethane. This can improve insulation values ​​and / or simplify production.

[0083] The bulk material can be further arranged in bags or tubes, for example made of textile or paper. This reduces the risk of the material shifting, for example during transport. It can also simplify the manufacturing process.

[0084] In addition to or as an alternative to the infill material, one or more installation lines, such as power and / or data lines or utility lines like water or gas lines, or one or more conduits for them, can run through the space between or between the protruding sections of the web elements, in particular through the channels formed by the protruding sections of the web elements and the chord elements. The one or more installation lines or one or more conduits can, for example, be arranged between the bottom chord elements and the infill material and / or be embedded in the infill material. Furthermore, the one or more conduits can run, for example, in the stacking direction and / or longitudinally.

[0085] The platform elements can have one or more openings for laying one or more installation cables and / or conduits. This allows the installation cables and / or conduits to be laid in the stacking direction.

[0086] In one embodiment, one or more bulkhead elements are arranged between the projecting sections of the web elements. In particular, a bulkhead element preferably blocks a channel formed by a bottom chord element and two adjacent web elements in the longitudinal direction. An upper part of the projecting sections of the web elements preferably extends beyond the one or more web elements for embedding in concrete. It is also conceivable that one or more of the bulkhead elements are also embedded in concrete.

[0087] With one or more bulkhead elements, particularly those located at the ends of a channel formed by a bottom chord element and two adjacent web elements in the longitudinal direction, especially in a closing grate area, the flow of grout into the channel can be limited when the timber-concrete composite element is laterally embedded in concrete, for example, to form a ring beam. Furthermore, the bulkhead elements can be used to position a filler material, such as bulk material, within the channel and prevent it from flowing out. This is particularly advantageous for securing timber-concrete composite elements during transport.

[0088] The one or more bulkhead elements are preferably made of wood. Alternatively, the one or more bulkhead elements can also be made of a wood-based material.

[0089] Further features and advantages of the semi-finished product, the wood-concrete composite element, its use and method will become apparent from the following description of exemplary embodiments, with reference to the attached drawing.

[0090] The drawing shows Fig. 1a-e shows a first embodiment of the semi-finished product, the timber-concrete composite element and the method for producing the timber-concrete composite element; Fig. 2a-b shows the use of the timber-concrete composite element made of Fig. 1a-e for the production of a timber-concrete composite ceiling, Fig. 3a-bein second embodiment of the precast element and the timber-concrete composite element, Fig. 4a-c web elements with shear cams of further embodiments of the precast element and the timber-concrete composite element and Fig. 5a-cein second embodiment of the method for producing the timber-concrete composite element.

[0091] The Fig. 1a-e show a first embodiment of the semi-finished part, the method for producing the wood-concrete composite element and the wood-concrete composite element. Fig. 1a shows a schematic perspective view of the semi-finished part without filler material. Fig. 1b shows a schematic perspective view of the semi-finished part after the addition of filler material and the placement of a reinforcing steel mat, Fig. 1c shows a perspective view of the finished wood-concrete composite element after the concrete layer has been applied and hardened. Fig. 1d shows a schematic cross-sectional view of the finished timber-concrete composite element according to the in Fig. 1c cutting plane designated with "Id" and Fig. 1e shows a schematic longitudinal section view of the finished timber-concrete composite element according to the in Fig. 1c section plane designated "Ie".

[0092] The semi-finished part 104 has a stacking arrangement 106 comprising several bottom chord elements 108 made of wood and several web elements 110, wherein the several bottom chord elements 108 and the several web elements 110 are arranged alternately next to each other in a stacking direction (arrow 112) and glued together, so that the bottom chord elements 108 and web elements 110 together form a bottom 114 and an opposite top 116 of the stacking arrangement 106.

[0093] The bottom chord elements 108 and the web elements 110 each extend in a longitudinal direction (arrow 118) transverse to the stacking direction 112 and are glued together in such a way that the bottom chord elements 108 are fully bonded, for example glued, with their side surfaces bordering the adjacent web elements 110.

[0094] The bottom chord elements 108 are made of solid structural timber, for example, from a single piece of solid structural timber extending along the entire longitudinal direction 118, or from several pieces joined one behind the other in the longitudinal direction 118 and transmitting tensile forces to each other, for example, by finger jointing. The bottom chord elements 108 have a width Bu in the range of 40–200 mm, preferably 60–150 mm, particularly 75–120 mm, in the stacking direction 112, and a height Hu in the range of 40–160 mm, preferably 50–100 mm, particularly 50–70 mm, in the vertical direction (arrow 120), i.e., in the direction from the bottom 114 to the top 116.

[0095] The web elements 110 are made of wood-based material, preferably OSB. On their underside, the web elements 110 are preferably flush with the bottom chord elements 108, so that the underside 114 formed by the web elements 110 and the bottom chord elements 108 is preferably flat. On their upper side 116, the web elements 110 have areas 122 projecting beyond the bottom chord elements 108 (see figure). Fig. 1d ). On an upper part 124 of the projecting areas 122, the web elements 110 are provided with a profile 126 in the form of a profiled web edge 128. The web edge 128 has a plurality of rectangular recesses 130 and cams 132 arranged between them, which enable a shear force-transmitting connection to a concrete layer.

[0096] The web elements 110 have a width Bs in the range of 10 - 25 mm, preferably 12 - 20 mm, in particular 14 - 18 mm, in the stacking direction 112, and a height Hs in the vertical direction (arrow 120) which is 50 - 600 mm, preferably 200 - 500 mm, in particular 250 - 400 mm, greater than the height Hu, so that the web elements 110 project 50 - 600 mm, preferably 200 - 500 mm, in particular 250 - 400 mm, beyond the bottom chord elements 108 on the top side 116.

[0097] The protruding areas 122 of the web elements 110 and the bottom chord elements 108 form several channels 134 running along the upper surface 116 in the longitudinal direction.

[0098] In the process for manufacturing a wood-concrete composite component, the following initially occurs as in Fig. 1a The semi-finished part 104 was shown provided.

[0099] Between the projecting areas 122 of the web elements 110, i.e. in the channels 134, the following is then carried out as in Fig. 1b The filler material 140 is arranged to form a filler material layer 142 interrupted by the web elements 110. The filler material layer 142 has a thickness d of at least 20 mm, preferably at least 50 mm. The upper part 124 of the web elements 110 projects beyond the filler material layer 142.

[0100] The filling material can be, for example, fibrous material such as glass wool or wood fibers, or foam material such as polyurethane foam. This can improve the thermal insulation properties. Alternatively, the filling material can also be loose fill, such as sand, gravel, crushed stone, or recycled material, which can increase the mass and thus improve the sound insulation properties.

[0101] In one or more of the channels 134, installation cables or conduits 172 can also be laid for this purpose. In particular, the installation cables or conduits can be pre-installed at the factory. Furthermore, it is conceivable to omit the fill material or provide less fill material in individual channels 134 to allow space for the subsequent installation of installation cables or conduits. In order to also be able to lay the installation cables or conduits in the stacking direction 112, openings 174 can be provided in the web elements 110 through which the installation cables or conduits can be guided.

[0102] Then, as in Fig. 1c shown, concrete is poured from above onto the fill material layer 142 and the upper parts 124 of the web elements 110 that protrude above the fill material layer, so that after the concrete has hardened a concrete layer 102 (in Fig. 1c (shown with dashed lines) forms a structure into which the upper parts 124 of the web elements 110 with the profile 126 are embedded. In this way, a shear force-transmitting connection between the bottom chord elements 108 and the concrete layer 102 is established via the web elements 110. In this process, the filler material 140 serves as a spacer for casting the concrete layer 102, so that a gap 144 remains between the bottom chord elements 108 and the concrete layer 102, in which the filler material 140 is arranged.

[0103] The concrete layer 102 can have reinforcement 160, in particular shrinkage reinforcement. To produce the reinforcement, for example, a reinforcing steel mesh 161 can be placed on the web elements 110 before the concrete layer 102 is poured (see figure). Fig. 1b Additionally or alternatively, reinforcing steel, especially made of steel, can also be placed in the stacking direction 112 through the recesses 130 of the web elements 110.

[0104] The reinforcement 160 of the timber-concrete composite elements 100 preferably extends beyond the concrete layer 102 in the longitudinal direction 118 (see Fig. 1e ). In this way, the protruding part 162 of the reinforcement 160 can later be, for example, embedded in a ring beam 164 (see Fig. 2b ).

[0105] In the present embodiment, the wood-concrete composite element 100 is pre-produced as a wood-concrete composite prefabricated element.

[0106] The Fig. 2a-b Illustrate the use of such a wood-concrete composite element 100 for the production of a wood-concrete composite ceiling. Fig. 2a shows one of the Fig. 1d corresponding schematic cross-sectional view and Fig. 2b one of the Fig. 1e corresponding longitudinal section view.

[0107] To produce the timber-concrete composite slab 190, several identical timber-concrete composite elements 100 are arranged side by side in the stacking direction 112, for example, resting on a support 148 at their ends in the longitudinal direction. The stacking arrangement 106 of the timber-concrete composite elements 100 has bottom flange elements 109 on each of its outer sides in the stacking direction 112, which preferably project beyond the concrete layer 102 in the stacking direction 112. In this way, the bottom flange elements 109 on the outer side in the stacking direction form a grout joint 150 at the joint of two timber-concrete composite elements 100, extending in the longitudinal direction 118, which can be filled with concrete to produce the timber-concrete composite slab 190, preferably with the insertion of joint reinforcement.A joint sealing tape 152 can be arranged, in particular glued in place, between the butt-jointed lower chord elements 109 of the adjacent timber-concrete composite elements 100.

[0108] The protruding part 162 of the reinforcement 160 can, for example, be embedded in a ring beam 164.

[0109] To prevent the liquid concrete from flowing into the channels 134 during the concreting of the ring beam 164, bulkhead elements 170 are arranged between the protruding areas 122, i.e. in the channels 134 (see. Fig. 1e & 2b ), which close off the channels 134 at the ends in the longitudinal direction 118. Further bulkhead elements 171 may be provided in the longitudinal direction, for example to prevent the fill material from shifting during transport to the construction site.

[0110] The precast element 104 can also be used directly for the production of the timber-concrete composite slab 190, without the need for prior production of precast timber-concrete components. For this purpose, several identical precast elements 104 without a concrete layer 102 can be arranged side by side, for example, resting on the support 148, and the filler material 140 can be placed in the channels 134. The concrete layer 102 can then be produced using cast-in-place concrete, simultaneously filling the joints, for example. In this way, the several adjacent precast elements 104 can be connected with a continuous concrete layer 102.

[0111] The Fig. 3a-b show a second embodiment of the semi-finished product and the wood-concrete composite element. Fig. 3a shows one of the Fig. 1d corresponding schematic cross-sectional view and Fig. 2b one of the Fig. 1e corresponding schematic longitudinal section view.

[0112] The semi-finished component 204 and the timber-concrete composite element 200 each have a similar structure to the semi-finished component 104 and the timber-concrete composite element 100. Corresponding components are marked with the same reference numerals, and reference is made to the above description of the Fig. 1a-e referred.

[0113] The semi-finished component 204 and the timber-concrete composite element 200 differ from the semi-finished component 104 and the timber-concrete composite element 100, respectively, in that a panel 280 is arranged on the underside 114 of the stacking arrangement 106 and is bonded to the underside 114 over its entire surface. The panel 280 is a wood-based panel, preferably OSB. The panel 280 can distribute forces occurring in the stacking arrangement 106. Furthermore, the panel can reduce local swelling or warping of the stacking arrangement 106 due to moisture.

[0114] The panel 280 preferably has a thickness of at least 20 mm and / or comprises fire-retardant additives or a fire-retardant coating. In this way, the fire protection of the semi-finished component 204 or the wood-concrete composite element 200 can be improved.

[0115] The panel 280 can have a decoration and / or a resin layer on the side facing away from the stacking arrangement 106, which forms the lower visible side 282 of the semi-finished part 204 or wood-concrete composite element 200.

[0116] The Fig. 4a-c Figure 1 shows web elements of further embodiments of the semi-finished part. The web elements 310, 310' and 310" differ from the web element 110 of the semi-finished part 104 in that the recesses 330, 330' and 330" and cams 332, 332' and 332" of the profiling 326, 326' and 326" of the web edge 128 are designed differently.

[0117] In Fig. 4a The recesses 330 and cams 332 are dovetail-shaped. The upper surfaces of the cams 332 and recesses 330 can, for example, have a length LN or LA in the direction of extension of 50 mm and a height HN or depth of 20 mm. The inclined side surfaces 333 (flanks) between the cams 332 and recesses 330 can, for example, have an angle α of 15° to the vertical direction 120. Such a profile 326 allows for an even better bond to the concrete layer, especially under tensile forces perpendicular to the plane of the concrete layer.

[0118] In Fig. 4b The recesses 330' are rectangular with undercuts 331 on both sides. Each undercut 331 has an undercut surface 335 parallel to the upper surface of the cams 332'. The upper surfaces of the cams 332' and recesses 330' can, for example, have a length LN or LA in the direction of extension of 50 mm and a height HN or depth of 20 mm. Such a profile 326' also ensures a good connection to the concrete layer even under tensile forces perpendicular to the plane of the concrete layer, while deflecting forces from the longitudinal to the vertical direction, which occurs with the inclined side surfaces 333, is prevented. Fig. 4a This can prevent occurrences.

[0119] In Fig. 4c The recesses 330" and cams 332" are designed as a one-sided dovetail and accordingly have a vertical side surface 336 and an inclined side surface 337. The individual cams 332" are arranged such that the vertical side surface 336 of each cam 332" faces the center of the web element 310" in the longitudinal direction, and the inclined side surface 337 faces away from the center. With such a profile 326", a good connection to the concrete layer can also be achieved even under tensile forces perpendicular to the plane of the concrete layer. The arrangement of the vertical side surfaces 336 in Fig. 4c A deflection of forces from the longitudinal to the vertical direction, away from the typical force direction for the application, is avoided.

[0120] The web elements 310, 310' or 310" can in particular be used instead of the web element 110 of the semi-finished part 104 made of Fig. 1a-e or Fig. 3a-b be used.

[0121] The Fig. 5a-c Figure 1 shows a second embodiment of the method for manufacturing the timber-concrete composite element in a schematic cross-sectional view. To manufacture the timber-concrete composite element 400 as a precast timber-concrete composite, the following steps are taken, as shown in Figure 2: Fig. 5a shown, a semi-finished part 404 provided, which, for example, is like the semi-finished part made of Fig. 1a-e can be trained. Corresponding components are in Fig. 1a-e and Fig. 5a-c with the same reference numerals, and reference is made to the above description of the Fig. 1a-e referred to. Alternatively, the semi-finished part 404 can also be used like the semi-finished part 204. Fig. 3a-b be trained. Furthermore, as also in Fig. 5a shown, concrete 401 was poured into a concrete layer mold 490.

[0122] The semi-finished part 404 is then processed as described in Fig. 4b The protruding sections 122 of the web elements 110 are oriented downwards, and at least the upper part 124 of the protruding sections 122 of the web elements is immersed in the uncured concrete 401 in the concrete layer mold 490. Alternatively, the precast element 404 can first be arranged in the concrete layer mold with the upper part of the protruding sections of the web elements in place, and then the concrete 401 can be added.

[0123] After the concrete 401 has hardened, a concrete layer 102 has formed, into which the upper part of the protruding sections of the web elements is embedded. The finished wood-concrete composite element 400 can be removed from the concrete layer mold 490.

[0124] The previously described method allows the size of the gap 144 to be adjusted independently of the thickness of the filler material. Furthermore, filler material can also be introduced into the channels 134 or gaps 144 only after the concrete layer 102 has hardened. Bezugszeichenliste:

[0125] 100, 200, 400 Timber-concrete composite element 102 Concrete layer 104, 204, 404 Semi-precast element 106 Stacking arrangement 108, 109 Bottom chord element 110, 310, 310', 310" Web element 112 Stacking direction 114 Bottom of stacking arrangement 116 Top of stacking arrangement 118 Longitudinal direction 120 Vertical direction 122 Projecting area of ​​web element 124 Upper part of the projecting area 126, 326, 326', 326" Profiling 128 Web edge 130, 330, 330', 330" Recess 132, 332, 332', 332" Cam 134 Channel 140 Filling material 142 Filling material layer 144 Gap 148 Support 150 Grouting joint 152 Joint sealing tape 160 Reinforcement 161 Reinforcing steel mesh 162 Protruding part of the reinforcement 164 Ring beam 170, 171 Bulkhead element 172 Conduit 174 Opening 190 Timber-concrete composite slab 280 Slab 282 Lower visible side 331 Undercuts 333, 336, 337 Side surface 335 Undercut surface 401 Concrete 490 Shape

Claims

1. Semi-finished component (104, 204, 404) for the production of a timber-concrete composite element (100, 200, 400), in particular a timber-concrete composite slab or a timber-concrete composite precast element, - with a stacking arrangement (106) comprising several bottom chord elements (108, 109) made of wood and several web elements (110, 310), wherein the several bottom chord elements (108, 109) and the several web elements (110, 310) are arranged side by side in a stacking direction (112) and glued together, so that the bottom chord elements (108, 109) and the web elements (110, 310) together form a bottom (114) and an opposite top (116) of the stacking arrangement (112), - wherein the web elements (110, 310) are attached to the top (116) areas (122) projecting beyond the lower chord elements (108, 109) for their at least partial embedding in concrete, characterized by - thatthe several lower chord elements (108, 109) and the several web elements (110, 310) are arranged alternately next to each other in the stacking direction (112) and - that the bridge elements (110, 310) are made of wood-based material.

2. Semi-finished product according to claim 1, characterized by the fact that the lower chord elements (108, 109) are made of structural timber, preferably of longitudinally bonded, in particular finger-jointed, structural timber.

3. Semi-finished product according to claim 1 or 2, characterized by the fact that the lower chord elements (108, 109) in the stacking direction (112) have a width in the range of 40 - 200 mm, preferably 60 - 150 mm, in particular 75 - 120 mm and / or a height in the range of 40 - 160 mm, preferably 50 - 100 mm, in particular 50 - 70 mm.

4. Semi-finished product according to one of claims 1 to 3, characterized by the fact thatthe wood material of the web elements (110, 310) contains wood chips, in particular the web elements (110, 310) are made of chipboard or OSB panels.

5. Semi-finished product according to one of claims 1 to 4, characterized by the fact that the web elements (110, 310) in the stacking direction (112) have a width in the range of 10 - 25 mm, preferably 12 - 20 mm, in particular 14 - 18 mm and / or the areas (122) of the web elements (110, 310) projecting on the top (116) over the bottom chord elements (108, 109) have a height in the range of 20 - 600 mm, preferably 200 - 500 mm, in particular 250 - 400 mm.

6. Semi-finished product according to one of claims 1 to 5, characterized by the fact that the protruding areas (122) of the web elements (110, 310) are provided with a profile (126, 326, 326', 326"), in particular having a profiled web edge (128).

7. Semi-finished product according to one of claims 1 to 6, characterized by the fact thata plate (280) is provided on the underside (114) of the stacking arrangement (106), which is in particular bonded to the underside (114).

8. Semi-finished product according to one of claims 1 to 7, characterized by the fact that a filling material (140) is arranged between the protruding areas (122) of the web elements (110, 310) and / or one or more installation lines or empty conduits (172) run for this purpose.

9. Semi-finished product according to one of claims 1 to 8, characterized by the fact that Between the protruding areas (122) of the web elements (110, 310) one or more bulkhead elements (170, 171) are arranged.

10. Semi-finished product according to one of claims 1 to 9, characterized by the fact that the stacking arrangement (106) has a width in the stacking direction (112) in the range of 0.5 - 2.5 m, preferably 0.75 - 2 m, in particular 1 - 1.5 m, and / or a length in the longitudinal extension direction (118) in the range of 1 - 15 m, preferably 2.5 - 10 m, in particular 5 - 8.5 m.

11. Timber-concrete composite element (100, 200, 400), in particular timber-concrete composite slab or timber-concrete composite precast element, - with a semi-precast element (104, 204, 404) according to one of claims 1 to 10 and - with a concrete layer (102), - wherein the protruding areas (122) of the web elements (110, 310) are embedded in the concrete layer (102) at least in an upper part (124).

12. Timber-concrete composite element according to claim 11, characterized by the fact that A space (144) is provided between the lower chord elements (108, 109) and the concrete layer (102), wherein a filling material (140) and / or one or more installation lines or empty conduits (172) preferably run through the space (144) in the space (144).

13. Use of a semi-finished product (104, 204, 404) according to one of claims 1 to 10 for the production of a wood-concrete composite building element (100, 200, 400), in particular according to one of claims 11 or 12.

14. Use according to claim 13, characterized by the fact that the protruding areas (122) of the bridge elements (110, 310) are at least partially embedded in concrete.

15. Method for producing a wood-concrete composite element (100, 200, 400) according to claim 11 or 12, - in which a semi-finished part (104, 204, 404) according to one of claims 1 to 10 is provided, - in which at least an upper part (124) of the projecting areas (122) of the web elements (110, 310) of the semi-finished part (104, 204, 404) is embedded in uncured concrete, so that when the concrete cures a concrete layer (102) is formed in which at least the upper part (124) of the projecting areas (122) of the web elements (110, 310) is embedded, and - in which optionally a filler material and / or one or more installation lines or conduits for it are arranged between the projecting areas (122).

16. Method according to claim 15, characterized by - thatthe semi-finished part with the protruding areas (122) of the web elements (110, 310) is arranged upwards and the uncured concrete, in particular as cast-in-place concrete, is applied to the timber-concrete composite element (100, 200, 400) or - that the semi-finished part with the protruding areas (112) of the web elements (110, 310) is oriented downwards and is immersed with at least the upper part of the protruding areas of the web elements in uncured concrete.

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