EP3230533B1

EP3230533B1 - Coupling element for a timber-concrete ceiling composite construction

Info

Publication number: EP3230533B1
Application number: EP15766732.0A
Authority: EP
Inventors: Jana DANKOVÁ; Tereza MURINOVÁ; Pavel MEC
Original assignee: Vysoka Skola Banska Technicka Univerzita Ostrava
Current assignee: Vysoka Skola Banska Technicka Univerzita Ostrava
Priority date: 2014-12-12
Filing date: 2015-07-01
Publication date: 2020-06-17
Anticipated expiration: 2035-07-01
Also published as: CZ2014901A3; EP3230533A1; WO2016091227A1

Description

Field of the Invention

The solution concerns a coupling element for a timber-concrete ceiling composite construction.

Background of the Invention

Timber ceiling constructions in construction objects are stressed mainly by bending, but dynamic stresses are also important, for example the vibrations of walkable ceilings. The disadvantages of standard construction solutions of timber ceilings are their low fire resistance, inconvenient acoustic properties and low solidity of the construction. There are currently many methods of realizing a coupled timber-concrete composite cross-section on an existing ceiling construction. It is a coupling system with discrete components (nails, screws, bolts, special screws).
The coupling system using perforated bars made from hard-wearing waterproof plywood without any surface finishing is described in the Czech utility model CZ 25368 U1 .
The Czech utility model CZ 19783 U1 describes the technical solution of a combined roof beam for use in ceiling construction in new buildings as well as to replace existing ceiling beams or entire ceilings during building reconstruction. The technical solution lies essentially in the base part of the ceiling beam being formed by an elongated, beam-like body made from construction or glued laminated timber. At least one steel or plastic perforated bar, which is in the vertical plane, is glued parallel to its lengthwise axis onto the base part, partially embedded and its protruding part is perforated to insert the steel reinforcement of the concrete panel. The timber beam is the support part of the concrete ceiling construction in ground constructions, mainly housing ones. The combined ceiling beam with a glued steel or plastic coupling bar is composed of an elongated beam-like body, onto which a steel or perforated bar is glued using a coating of glue. In the construction the combined ceiling beam with a glued perforated bar is composite with the reinforced concrete ceiling panel.
The Czech patent application CZ20130187 A3 describes the invention of composite materials, specifically timber-concrete beams. A coupled timber-concrete composite ceiling beam consists of a timber part and a reinforced concrete part. The timber part is made from glued laminated timber and its dimensions are designed based on the load demands and the span of the final construction in which the beam will be used. A continuous groove of special dimensions and geometry is cut in the top face of the timber part of the profile and in its axis. A coupling bar made from hard-wearing waterproof plywood without any further surface working is glued into the groove. The bar is made as an infinite component, its length is derived from the length of the beam.
The Czech utility model application CZ 27419 U1 describes the technical solution of support ceiling constructions, specifically composite timber-concrete beams. The composite timber-concrete beam coupled with metal components is composed of a timber and reinforced concrete panel. The reinforced concrete panel is made from concrete that has concrete reinforcement built into it, following which the surface of the panel is polished. At least one timber beam with perforated metal plates is placed onto such finished panel in a way that the plates are embedded into the base concrete panel. The length of the plates not covered in concrete is at least one third. The connection of the perforated plates with the timber beam is executed by convex nails. The perforations on the plates are evenly placed.
The Czech utility model CZ 22590 U1 describes the technical solution of the structural strengthening of the existing timber beam ceiling construction. This solution is particularly suitable for old, historically preserved objects. The solution lies in attaching a coupling component onto at least part of one beam. This coupling component is securely connected to the concrete support construction placed above the timber beams. The technical solution also lies in the concrete support construction consisting of a monolithical, reinforced concrete panel and the concrete support construction being formed by a fibre-reinforced concrete panel. It is further important that the coupling component is composed of a bed bearer, whose bottom part is placed in the groove on the top surface of the beam, wherein the empty space in the groove is filled up with glue. The bed bearer has openings into which the armature components of the concrete support construction are situated.
The Czech utility model CZ 22649 U1 describes a ceiling construction equipped with a floor construction composed of layers of impact sound and acoustic insulation, particularly the construction of a beam ceiling composed of timber beams with joists. The solution lies in the acoustic insulation being formed of at least one layer of fibre-reinforced concrete panels. A flexible film may be placed on the layer of fibre-reinforced concrete panels and on top of it the floor itself. The ceiling construction may be a beam ceiling made of timber beams with a joist, on top of which, in the family house version, is placed a layer of impact sound insulation, and placed on top of that is a layer composed of more than two fibre-reinforced concrete panels lying on each other. In the beam ceiling version, that is more demanding in acoustic insulation, a flexible film is placed over the joist, on this film is placed a layer of more than two fibre-reinforced concrete panels, on this is placed a layer of impact sound insulation, on top of which is another layer composed of more than two fibre-reinforced concrete panels lying on each other. Timber beams may have a lower joist, which will have the function of cross sectional hardening. A plasterboard dropped ceiling may be hung on the lower joist, wherein there is a layer of mineral insulation between it and the joist.
The international patent application WO 9411589 presents the invention of a timber-concrete floor, which lowers the transition of shearing load between the timber and concrete. The floor contains a set of supports on brackets connected with the concrete panel. The connection between the timber and concrete is secured by a panel with iron spikes. The panels are partially inserted into the concrete and partially into the beams.
The US patent US 5809722 A discloses shearing connectors that reinforce concrete slab building structures supported with wood girder beams. The shearing connector has metal lengthwise extending horizontal frame and metal shear load transfer plates projecting down at both ends of the frame. The transfer plates of the connector are fixed to the girder beam in a groove pocket by means of mechanical fasteners (e.g. screws, bolts). The horizontal frame of the connector comprises a plurality of openings for reinforcing rods and there is an additional wire reinforcement mesh arranged around the reinforcing rods. A concrete slab is poured over the shearing connectors, the reinforcing rods and the wire reinforcement mesh in order to fix their position and the resulting compression load forces are thus transferred to the underlying wooden beam. Such connection of wood and metal might cause mutual corrosion of these materials at humidity levels higher than roughly 60 %. The resulting shear force between the wood girder beam and the metal shearing connector is absorbed only by the fasteners in the groove pockets, which might cause weakening of the wooden beam material at the pocket sites. In addition, the mechanical fastening of the connectors to the wood girder beams poses a disadvantage due to inflexibility in adjusting hardness and stiffness of the whole building structure.
The European patent application EP 0939175 A2 discloses a metal connecting element for assembling wood and concrete. The connecting element has an elongated rectangular-shaped body with a plurality of anchors arranged on top, comprising angled feet alternatingly extending from both sides of the body and further with positioning elements projecting sideways from the body. The connecting element is fixed to the underlying wooden beam by means of a glued connection in a groove and with screws fastening the positioning elements to the wooden beam. The elongated body comprises a plurality of openings for reinforcing rods. A concrete slab is poured over the connecting element and the reinforcing rods in order to fix their position in relation to the wooden beam. Similarly, such connection of wood and metal might cause mutual corrosion of these materials at humidity levels higher than roughly 60 %, which might in turn affect the glue used at the interface of the connection. Moreover, double investment and construction requirements arise as the system comprises a glued and a mechanical connection at the same time. The concrete to be cast over the connecting elements would have to be of high fluidity, to consist of fine particles and the pouring would have to be carried out with care in order not to damage the anchors or angled feet. Otherwise, the main coupling elements would only be the mechanical fasteners (screws), and not the glued connection.
The objective of the invention is to design a coupled timber-concrete composite ceiling construction, which facilitates the realization of ceiling constructions that can transfer higher loads on larger dividers than is usually possible with this material and constructional arrangement of the particular construction.

Summary of the Invention

The objective of the invention is reached and the defects mentioned above are removed by a coupling element for a timber-concrete composite ceiling construction, wherein the coupling element is made from a timber-based material. The coupling element has a coupling bar implemented onto a timber body of the coupling element, while the coupling bar partially overreaches the surface of the body of the coupling element. The coupling bar has openings to insert the coupling reinforcements, and to connect with a ceiling beam through a glued connection, the coupling bar has a set of openings or grooves and toothing on the bottom edge. The coupling bar, which is made of timber, is an integral part of the coupling element and is securely connected with the body of the coupling element through a glued connection, which may be accomplished by using the appropriate glue when gluing in the workshop, so that the glued connection is secure and durable.
Preferably, the body of the coupling element is formed by two parts, between which the coupling bar is inserted. To build the desired ceiling construction equipped with coupling elements it is favourable if the ceiling beams comprise grooves in which the coupling elements are arranged through a glued connection. A boarding is arranged between the coupling elements. Moreover, the coupling reinforcement is in contact with lengthwise reinforcements which are then as a whole covered by the concrete panel.
To ensure adequate heat or sound insulation of the ceiling construction equipped with coupling elements it is advantageous if there is insulation arranged between the coupling elements and placed on the boarding.
The solution of the timber-concrete composite ceiling construction lies in the creation of a composite timber-concrete cross-section in the ceiling construction, where the concrete, or rather the timber-concrete part is under pressure and the timber part is predominately strained by pulling, or rather bending. This effect is ensured using the specially shaped and arranged coupling element, which has a coupling bar implemented in it, which may have a variable shape as well as having a specific material composition. It is made from a hard-wearing waterproof thin timber plywood. The coupling bar is glued between the timber body of the coupling element and is its fixed component. The coupling bar is glued symmetrically to the centre of the body of the coupling element and the coupling bar partially overreaches its profile. The bar has openings to insert the coupling reinforcements and on the opposite end it is arranged in the groove formed in the timber coupling element. During its installation the coupling element is glued onto the top face of the ceiling beam, in which a groove for its gluing has been formed beforehand. There are openings made in the coupling bar, which is a fixed component of the coupling element, and the concrete reinforcement is inserted into these openings, this reinforcement extends up to the constructional concrete lengthwise reinforcement, wherein both these reinforcements are covered in concrete and form the reinforced concrete parts of the ceiling.
This arrangement of the timber-concrete composite ceiling construction allows for the realization of acoustic and/or thermally-technical measures, which is ensured by inserting appropriate insulation between the coupling elements.
The ceiling construction created with the technology "Coupled timber-concrete composite ceiling construction DB-ECO II" has a higher load capacity and toughness, wherein the higher toughness means a higher resistance to vibration as opposed to traditional timber ceiling constructions. This arrangement of the construction also allows for the realization of other construction measures and therefore the construction may achieve above standard qualities.

Clarification of Figures

The invention is further described using pictures, where Fig. 1 shows a sectional view of the ceiling construction with inserted coupling elements, Fig. 2a shows a sectional view of the coupling element with the extended coupling bar, Fig. 2b shows an embodiment of the coupling bar with shallow grooves, Fig. 2b shows an embodiment of the coupling bar with circular openings and Fig. 2c shows a side view of the coupling element with the implemented coupling bar and Fig. 3 shows a side sectional view of the ceiling construction with inserted coupling elements.

Exemplary Embodiments of the Invention

The invention concerns the coupling element 4, which is depicted in Fig. 2a, Fig. 2b and Fig. 2c. The coupling element 4 in this embodiment has a coupling bar 9 implemented into the timber body 10 of the coupling element 4, which partially overreaches the surface of the body 10 of the coupling element 4, wherein to insert the coupling reinforcements 6, the coupling bar 9 has several openings 11 and for connection with the timber construction component, the coupling bar 9 has a series of openings 14 or grooves 12 and on the bottom edge also toothing 13. Coupling elements 4 can be arranged in the construction in various ways, e.g. close behind one another, with spaces between them, etc. The size of the coupling elements 4 is limited by the shape of the existing timber construction which is to be redeveloped using this technology and further limited by the weight of the coupling element 4 so that the gluing of the coupling element 4 into the top part of the ceiling beam 1 is feasible under the conditions of the construction site. As it is apparent from the enclosed figures, i.e. Fig. 2b and Fig. 2c, the shape of the coupling bar 9 is dependent on the method of gluing and the type of glue.
The technology of the composite construction elements is provided by the coupling system as described in this invention, which is the bearer of a higher load capacity and toughness of the ceiling construction. The technology is applicable on existing timber ceiling constructions, an example of such ceiling construction is depicted in Fig. 1. The coupling elements 4 are made in the workshop using an industrial, or rather a workshop method. It is a timber product, which may be made using for example in the technologies of producing glued laminated timber, further referred to as GLT (LLD) so that when the coupling element 4 is assembled in the workshop, the coupling bar 9 can be glued in geometrically precisely. The coupling element 4 is roughly shaped as a small sized panel, or rather its height is systematically smaller than its width and length. The size is limited by the total weight of the coupling element 4, wherein it is desirable to abide by the rule of easy manipulation with the coupling element 4 in the construction site. In the centre of the width, along the entire length of the body 10 of the coupling element 4, the industrial, or rather workshop method is used to implement the middle part of the coupling bar 9, which is a fixed component of the coupling element 4 and overreaches (overhangs) its top face and under its bottom face. The coupling bar 9 protrudes over the top face of the coupling element 4 with the part where it has circular openings 11 to insert the coupling reinforcement 6. The coupling bar 9 protrudes over the bottom of the coupling element 4 with the part designed for the gluing of the ceiling beam 1 onto the pre-prepared groove 2 in its top face. The groove 2 is filled with suitable glue. And glue is also applied on the coupling bar, or rather on its part that is designed to be glued onto the groove 2 which is prepared for the gluing by treating its surface and applying the glue. Afterwards the coupling element 4 is inserted onto the groove 2, wherein the technological gluing process as specified by the glue manufacturer is abided. In the part designed for gluing the coupling bar 9 is treated using a special method. It is apparent from fig. 2a and fig. 2b that in the part designed for gluing onto the timber, the coupling bar 9 is equipped with toothing 13 and on the sides with shallow grooves 12 or perforations in the form of small openings 14. In the part which is designed for connection with the concrete, the coupling bar 9 has openings 11, for example circular, which are designed for insertion of the coupling reinforcement 6. These coupling reinforcements 6 are arranged perpendicularly to the lengthwise reinforcements 7 made from reinforced steel. In the spaces between the ceiling beams 1 where the effect of the coupling is not considered (composite T-profile) the insulation 5 may be placed, for example heat or acoustic insulation. This way the ceiling construction will be lightened and its heat insulation and acoustic characteristics will be improved. Finally the concrete is applied and both reinforcements are covered in concrete as a whole, which creates the concrete panel 8.

Industrial Application

The technology is applied as a new construction or as a reconstruction technology for reinforcing and narrowing of existing timber ceiling constructions.

LIST OF REFERENCE NUMBERS

1: Ceiling beam
2: Groove formed in the top face of the ceiling beam 1
3: Boarding
4: Coupling element
5: Heat or sound insulation
6: Coupling reinforcement inserted through the openings 11 in the coupling bar 9
7: Construction concrete reinforcement
8: Concrete part of the ceiling
9: Coupling bar
10: Body of the coupling element 4
11: Circular openings to insert the coupling reinforcement 6
12: Shallow grooves on both sides of the bar 9
13: Toothing on the bottom edge of the bar 9
14: Small openings (perforations) along the entire width of the bar 9

Claims

Coupling element (4) for a timber-concrete ceiling composite construction, wherein the coupling element (4) is made from a timber-based material, wherein the coupling element (4) has a coupling bar (9) implemented onto a timber body (10) of the coupling element (4), while the coupling bar (9) partially overreaches the surface of the body (10) of the coupling element (4), wherein to insert a coupling reinforcement (6), the coupling bar (9) has openings (11) and to connect with a ceiling beam (1) through a glued connection, the coupling bar (9) has several openings (14) or grooves (12) and toothing (13) on the bottom edge, and wherein the coupling bar (9) is an integral part of the coupling element (4) and is securely connected with the body (10) of the coupling element (4), characterized in that the coupling bar (9) is made of timber and in that the coupling bar (9) is connected with the body (10) of the coupling element (4) through a glued connection.
Coupling element (4) according to claim 1, characterised in that the body (10) of the coupling element (4) is formed by two parts, between which the coupling bar (9) is inserted.
Ceiling construction comprising coupling elements (4) according to claims 1 and 2, characterised in that the ceiling beams (1) comprise grooves (2) in which the coupling elements (4) are arranged through a glued connection and between coupling elements (4) a boarding (3) is arranged, wherein the coupling reinforcement (6) inserted through the openings (11) of the coupling element (4) is in contact with lengthwise reinforcements (7) which are covered in a concrete panel (8) as a whole.
Ceiling construction comprising coupling elements (4) according to claim 3, characterised in that an insulation (5) is arranged between the coupling elements (4) and placed on the boarding (3).