WO2024133973A1

WO2024133973A1 - Fastening between timber slab and beam with shear load bearing and assembly/disassembly capacities

Info

Publication number: WO2024133973A1
Application number: PCT/EP2024/050043
Authority: WO
Inventors: Christoph ODENBREIT; Alfredo ROMERO; Jie Yang; Nicoleta POPA
Original assignee: Université Du Luxembourg
Priority date: 2022-12-23
Filing date: 2024-01-02
Publication date: 2024-06-27
Also published as: LU503246B1

Abstract

The invention is directed to a kit (110) for fastening a slab (106, 108) to a beam (104), comprising a lower plate (110.1) with a central hole, applied on a lower face (106.2, 108.2) of the slab; an upper plate (110.3) with a central hole, applied on an upper face (106.1, 108.1) of the slab; a tubular spacer (110.2) extending through the slab; a bolt (110.4) inserted through the central hole of the upper plate (110.3), the tubular spacer (110.2), the central hole of the lower plate (110.1) and a hole in the beam (104); a nut (110.5) engaging with the bolt (110.4) and resting on the beam (104); wherein the lower plate (110.1) is permanently linked to the tubular spacer (110.2) while the upper plate (110.3) is not permanently linked to the tubular spacer (110.2) so as to allow insertion of the tubular spacer (110.2) in a drilling in the slab from its lower face.

Description

FASTENING BETWEEN TIMBER SLAB AND BEAM WITH SHEAR LOAD BEARING AND ASSEMBLY/DISASSEMBLY CAPACITIES

The invention is directed to the field of construction, more particularly building construction, and assembly between a slab and a beam.

Prior art patent document published CA 2 569 814 A1 discloses a system of kit for fastening a composite wood-glass fibre reinforced polymer slab to an underlying steel beam. The system or kit comprises a fibre-reinforced epoxy mat that is disposed between the slab and the beam, an anchor that is inserted through the slab and the beam from an upper face of the slab, and securing means engaging with the anchor. The anchor comprises an upper plate applied on the upper face of the slab, and one or two rods rigidly attached to and extending from the upper plate through the slab. The anchor comprises also one or two threaded connector pins engaging into and extending from distal front faces of the rod(s). The securing means comprise one or two nuts that engage with extending threaded portions of the one or two connector pins. This system is specifically designed for supporting large shear forces while avoiding transmitting additional uncontrolled stresses to the inside of the pre-cast slabs when the latter show different casual cambers. This is presumably the reason why the system makes use of the threaded connectors with a smaller diameter than the rods. The shear forces supporting capacity of that system is dependent on the fibre-reinforced epoxy mat and the applied compression forces. It is subject to improvement, in particular for timber slabs showing a lower rigidity notably in compression.

Prior art patent document published CN 105735464 A discloses an assembly system between a concrete slab and a steel beam, consisting essentially of bolts extending through the holes formed in the slab and in the underlying flange of the beam and nuts engaging with the bolts. This assembly, as such classical, shows a limited shear forces bearing capacity, essentially because limited by the compression force that the assembly can exert without damaging the slab.

Prior art patent document published CN 103924674 A discloses an assembly system between a concrete slab and a steel beam, whereas the assembly comprises an upper plate, a lower plate and tubular spacers between the upper and lower plates. The tubular spacers are rigidly welded to each of the upper and lower plates so as to form a rigid assembly to which the concrete material of the slab is precast. This assembly presumably provides a good shear force bearing capacity in that the tubular spacers between the upper and lower plates allow the application of high compressive force by the bolts and nuts without damaging the slab. This solution is however limited to slabs made of cast material and also does not allow a disassembly of the system from the slab which is desirable for future reuse or recycling purposes.

The invention has for technical problem to overcome at least one drawback of the above cited prior art. More specifically the invention has for technical problem to provide an assembly between one or several slab and one or several beam that can bear high shear forces while being easily to assemble and disassemble, notably for reuse or recycling purposes.

Technical solution

The invention is directed to a sub-assembly for fastening a slab to a beam, comprising: a plate with a central hole, for being applied on a lower face of the slab; a tubular spacer for extending through the slab between the plate and an opposed plate with a central hole, for being applied on an upper face of the slab; the tubular spacer and the plate being metallic and designed for being engaged by a bolt engaging also a hole in the beam; wherein the plate is permanently attached to a proximal end of the tubular spacer while a distal end of the tubular spacer is free of permanent link to the opposed plate so as to allow insertion of the tubular spacer in a drilling in the slab from its lower face.

According to a preferred embodiment, the plate is circular.

According to a preferred embodiment, each of the plate has an outer diameter comprised between 50 and 100mm, preferably between 60mm and 90mm.

According to a preferred embodiment, the plate and the tubular spacer show a total length along a longitudinal axis that is comprised between 120mm and 200mm.

According to a preferred embodiment, the central hole of the plate and an inner diameter of the tubular spacer is of at least 18mm and/or at most 26mm, preferably of 22mm.

According to a preferred embodiment, the plate shows a thickness of at least 3mm and/or the tubular spacer shows a wall thickness of at least 5mm.

According to a preferred embodiment, the plate is provided around the central hole with means for directly anchoring said plate to the slab.

According to a preferred embodiment, the anchoring means on the plate comprise pointed protrusions extending towards the tubular spacer, so as to penetrate the slab upon insertion of the tubular spacer in the drilling in the slab and upon tightening of the bolt.

According to a preferred embodiment, the pointed protrusions are evenly distributed around the central hole.

According to a preferred embodiment, the pointed protrusions are integrally formed with the plate.

According to a preferred embodiment, the pointed protrusions and the plate form a metallic moulded part.

According to a preferred embodiment, the pointed protrusions and the plate form a stamped and bent metallic part.

According to a preferred embodiment, the anchoring means on the plate comprise anchoring holes inclined relative to the longitudinal direction so as to receive anchoring screws extending into the slab in a diverging manner relative to said longitudinal axis.

According to a preferred embodiment, each of the anchoring holes is countersunk so as to form a conical seating surface for a countersunk head of the anchoring screws.

According to a preferred embodiment, the inclination of each of the anchoring holes is comprised between 15° and 45°.

The invention is also directed to a kit for fastening a slab to a beam, comprising: a lower plate with a central hole, for being applied on a lower face of the slab; an upper plate with a central hole, for being applied on an upper face of the slab; a tubular spacer for extending through the slab between the lower plate and the upper plate; a bolt for being inserted through the central hole of the upper plate, the tubular spacer, the central hole of the lower plate and a hole in the beam; a nut for engaging with the bolt and resting on the beam; wherein the lower plate and the tubular spacer form a fastening sub-assembly according to the invention.

The invention is also directed to an assembly comprising: a beam with at least one flange; at least one slab positioned against the at least one flange; at least one sub-assembly or kit fastening the at least one slab to the at least one flange; wherein the at least one fastening sub-assembly or the at least one fastening kit is according to the invention.

According to a preferred embodiment, the at least one slab is made of wood.

According to a preferred embodiment, the at least one slab comprises two slabs arranged side by side on the at least one flange, and several of the at least one fastening kit fastening each of the two slabs to the at least one flange along the longitudinal axis of the beam.

The invention is also directed to a method of fastening a slab to a beam, comprising the steps: positioning the slab onto the beam; fastening the slab to the beam using at least one fastening sub-assembly or kit; wherein the at least one fastening sub-assembly or the at least one fastening kit is according to the invention.

According to a preferred embodiment, the method further comprises the following step prior the positioning step: inserting the tubular spacer of the at least one fastening sub-assembly or kit into the drilling in the slab from the lower face of said slab.

According to a preferred embodiment, the fastening step comprises inserting the bolt through the central hole of the opposed or upper plate and the tubular spacer, the central hole of the lower plate and the hole of the beam, engaging the nut with the bolt so as to rest on the beam, and tightening the bolt and nut.

According to a preferred embodiment, the hole in the beam is formed prior the positioning step or after the position step using the tubular spacer as guide for a drill.

Additional aspects of the invention:

1. An assembly comprising: a beam; at least one slab positioned on the beam and having a tubular spacer, of at least one fastening sub-assembly, inserted into a drilling in the slab from the lower face of said slab, the at least one fastening sub-assembly comprising, in addition to the tubular spacer, a lower plate with a central hole, the lower plate being permanently linked to a proximal end of the tubular spacer while a distal end of the tubular spacer is free; an opposed or upper plate with a central hole applied on the upper face of the slab; a bolt inserted through the central hole of the opposed or upper plate, the tubular spacer, the central hole of the lower plate and a hole of the beam; a nut engaged with the bolt so as to rest on the beam.

2. A method of fastening a slab to a beam, comprising the steps: providing the slab with a tubular spacer, of at least one fastening sub-assembly, inserted into a drilling in the slab from the lower face of said slab, the at least one fastening sub-assembly comprising, in addition to the tubular spacer, a lower plate with a central hole, the lower plate being permanently linked to a proximal end of the tubular spacer while a distal end of the tubular spacer is free; positioning the slab onto the beam; fastening the slab to the beam, the fastening step comprising: applying an opposed or upper plate with a central hole on an upper face of the slab, inserting a bolt through the central hole of the opposed or upper plate, the tubular spacer, the central hole of the lower plate and a hole of the beam, engaging a nut with the bolt so as to rest on the beam, and tightening the bolt and nut, wherein the hole in the beam is formed prior the positioning step or after the position step using the tubular spacer as guide for a drill.

3. The method according to 2 comprising the following steps prior to the provision step: drilling the slab; providing at least one fastening sub-assembly comprising a tubular spacer and a lower plate with a central hole, the lower plate being permanently linked to a proximal end of the tubular spacer while a distal end of the tubular spacer is free; inserting the tubular spacer from the lower face of said slab until the lower plate is applied on a lower face of the slab.

4. The method according to 2 or 3, wherein the bolt and nut are tightened until the upper plate contacts the upper edge of the tubular spacer.

Advantages of the invention

The invention is particularly interesting in that it provides an assembly between a slab and a beam that can bear high shear forces while being easy to assemble and disassemble e.g., for reuse or recycling purposes. The assembly does not require using any kind of chemical or wet filler. The slabs can be pre-drilled and, if applicable, pre-bored or drilled and, if applicable, counter-bored on site. The tubular spacer, to which the lower plate is fixed, can be inserted into the drilling of the slab on site or previously while the slabs are being prepared in a workshop. The same applies when, later on, dissembling the slabs. The fastening kit of the invention, in addition to bearing high shear forces is very flexible in use.

Brief description of the drawings

is a section view of an assembly according to a first embodiment of the invention.

Description of an embodiment

is a sectional view of an assembly 102 according to a first embodiment of the invention.

The assembly 102 comprises a beam 104, for instance a steel beam being however understood that the beam can be made of a different material like timber or even be a composite beam made of different materials. The beam 104 is for instance an I-beam with a web 104.1 and two parallel flanges 104.2 where only the upper flange 104.2 is represented. The assembly 102 further comprises a first slab 106 and a second slab 108, with their lower faces 106.2 and 108.2 lying against the upper flange 104.2 of the beam 104. More specifically, each of the first slab 106 and the second slab 108 occupies about a respective half transversal portion of the upper flange 104.2, where the two resulting two half portions are on either side of a plane passing by the web 104.1. As this is apparent, the side faces 106.3 and 108.3 of the first slab 106 and second slab 108, being in vis-à-vis, are distant from each other by a distance of a few millimetres e.g., of at least 5mm and/or not more than 15mm.

The assembly 102 further comprises at least two fastening kits 110, each thereof fastening one of the first and second slab 106 and 108 to the beam 104.

The fastening kit comprises a lower plate 110.1 that is applied against the lower face 106.2 or 108.2 of the corresponding one of the first and second slabs 106 and 108. For instance, the lower plate 110.1 is located in a corresponding counterbore formed in the lower face 106.2 or 108.2 of the corresponding one of the first and second slabs 106 and 108, so that the lower plate is totally sunk. The lower plate 110.1 is for instance circular, essentially for manufacturing cost reasons, whereas on a technical point of view it can show other shapes, like an oval, a rectangle, a square, a triangle but bear in mind the concentration stresses in the slab arise with the different shapes of the lower plate. The lower plate 110.1 comprises a central hole that will be discussed below in connection with the bolt 110.4.

The fastening kit further comprises a tubular spacer 110.2 that extends transversally through the corresponding one of the first and second slabs 106 and 108, more specifically through a corresponding drilling of the corresponding one of the first and second slabs 106 and 108, said drilling extending from the upper face 106.1 or 108.1 to the lower face 106.2 or 108.2. The tubular spacer 110.2 shows an outer surface that is designed for allowing its full insertion into the corresponding drilling in the slab. To that end, the outer surface is preferably cylindrical with an outer diameter that is constant over a whole length of the tubular spacer. The tubular spacer 110.2 forms a channel that is preferably smooth (void of thread) with an inner diameter that is constant over a whole length of said tubular spacer, for facilitating insertion of a bolt and for reducing manufacturing costs.

The fastening kit further comprises an upper plate 110.3 that is applied against the upper face 106.1 or 108.1 of the corresponding one of the first and second slabs 106 and 108. The upper plate 110.3 is for instance circular, essentially for manufacturing cost reasons, whereas on a technical point of view it can show other shapes, like an oval, a rectangle, a square, a triangle. The upper plate 110.3 comprises a central hole similarly to the lower plate 110.1.

The tubular spacer 110.2 extends from an inner face of the lower plate 110.1 to an inner face of the upper plate 110.3 so as to contact these respective two inner faces and support the compressive forces generated in the bolt 110.4 and the nut 110.5 that will be described below. The tubular spacer 110.2 is rigidly fixed to the lower plate 110.1, e.g. by welding, but not to the upper plate 110.3. The lower plate 110.1 and the tubular spacer 110.2 form therefore a rigid part that can be inserted into the corresponding drilling in the corresponding one of the first and second slabs 106 and 108. The rigid fixation between the lower plate and the tubular spacer is also important and useful for properly bearing the shear forces in that these forces are thereby substantially better distributed to the whole thickness of the slab. The tubular spacer 110.2 and the lower plate 110.1 form a sub-assembly of the fastening kit, this sub-assembly being particular in that the tubular spacer and the lower plate are rigidly fixed.

The fastening kit further comprises a bolt 110.4, and a corresponding nut 110.5. The bolt 110.4 is inserted through the central hole of the upper plate 110.3, through the tubular spacer 110.2, through the central hole of the lower plate 110.1 and through a corresponding hole formed in the underlying upper flange 104.2 of the beam 104. It is understood that the central holes of the upper and lower plates 110.3 and 110.1, the tubular spacer 110.2 and the corresponding hole of the upper flange 104.2 are all aligned. Once the bolt 110.4 is inserted as above, the nut 110.5 is engaged on the thread end of the bolt 110.4, on a face of the upper flange 104.2 that is opposed to the face thereof that contacts the first and second slabs 106 and 108. The bolt 110.4 and nut 110.5 can then be tightened so as to generate a substantial compression force on the corresponding one of the first and second slabs 106 and 108 via the upper and lower plates 110.3 and 110.1. The compression force is transmitted to the lower plate 110.1 that is then pressed against the upper flange 104.2. This compression between the lower plate 110.1 and the upper flange 104.2, by virtue of the resulting frictional forces, renders the fastening kit 110 able to support significant shear forces that are then evenly distributed to the corresponding one of the first and second slabs 106 and 108.

Each of the upper and lower plates 110.3 and 110.1 can have an outer diameter that is greater than 150% of an outer diameter of the tubular spacer 110.2 and/or less than 250% of said outer diameter of said tubular spacer 110.2.

As illustrated, a washer can be provided between the bolt head and the upper plate 110.3 and also between the nut 110.5 and the upper flange 104.2 of the beam 104. Each of these two washers can be integrated in the bolt head and/or in the nut i.e., integrally formed therewith, as this is as such common practice in fasteners.

The longitudinal length of the tubular spacer 110.2 is advantageously dimensioned so as to be slightly shorter than the effective thickness of the corresponding one of the first and second slabs 106 and 108 e.g., by at least 1%, preferably 2%, more preferably 3%, and/or at most 5%, so that after tightening of the bolt 110.4 and nut 110.5 until the upper plate 110.3 contact the upper edge of the tubular spacer 110.2, the slab is compressed between the upper and lower plates 110.3 and 110.1. It may also be preferred that the longitudinal length of the tubular spacer 110.2 is shorter than the effective thickness of the slab by between 1 to 5 %, more preferably between 2 to 3%. In other words, after complete insertion of the unitary part formed by the lower plate 110.1 and the tubular spacer 110.2, the upper edge of the tubular spacer 110.2 is set back from the upper plate 110.3 when properly positioned on the corresponding one of the first and second slabs 106 and 108 but prior tightening of the bolt 110.4 and nut 110.5. This setback distance can be of 1% of the depth/thickness of the slab. The above numerical values of the longitudinal length of the tubular spacer being slightly shorter than the effective thickness of the corresponding one of the first and second slabs are to be understood as differences between said length and said thickness, expressed in percentage of said thickness.

In the above assembly, two slabs, i.e., a first slab 106 and a second slab 108, are assembled to a single beam 104. It is to be understood that other configurations are possible, while using the same fastening kit and principle, according to the invention. For example, only one slab can be assembled to the beam, whereby the slab needs not end at the beam, i.e., can extend transversally over the beam, meaning that the drilling(s) in slab need not be adjacent a side face of said slab. Also, the fastening kits can be distributed at regular intervals along the beam and/or along a side face of the slab.

In a general manner, the slab can be a timber slab, i.e., made predominantly of wood, like plywood or superimposed layers of wood fastened to each other by gluing. The slabs can show a thickness of at least 100mm and/or at most 200mm. The bolt is made of steel or stainless steel and can have a nominal diameter of at least 16mm and/or at most 24mm, preferably a diameter of 20mm. It is preferably made of steel with a metric grade or class of 8.8 or 10.9. The same applies accordingly to the nut. The drilling diameter in the slab(s) that receives the tubular spacer can be of at least 30mm and/or at most 40mm, preferably of 35mm. The tubular spacer has an outer diameter of at least 30mm and/or at most 40mm, preferably of 35mm. The tubular spacer has an inner diameter of at least 18mm and/or at most 26mm, preferably of 22mm. The tubular spacer can have a wall thickness of at least 5mm. The tubular spacer can be a portion of a hot-rolled steel tube of the grade S355 according to EN 10025-2 norm. The upper plate and/or the lower plate are preferably made of metallic material, e.g. steel, stainless steel or any metal alloy. They can have a thickness of at least 8mm and/or at most 12mm. Their central holes can be of at least 18mm and/or at most 26mm, preferably of 22mm according to the diameter of the bolt 110.4. Their outer diameter can be of at least 50mm, preferably 60mm and/or of at most 100mm, preferably 90mm.

In an example of the first embodiment, the demountable shear connection system consists of two steel plates 110.1 and 110.3 of 75mm diameter and 10mm in thickness with a central hole of 22mm in diameter, a hot-rolled steel tube 110.2 of steel S355 with an external diameter of 35mm and inner hole diameter of 22mm and 134mm in length, one partially-threaded M20 bolt 110.4 of Gr. 10.9 and of 180mm in length for a 144mm thickness timber slab panel 106, two M20 washers of Gr. 10.9 and one M20 nut 110.5 of Gr. 10.9. The steel tube 110.2 is connected with the steel plate 110.1 at the bottom by welding.

The installation method of the shear connection is as follows:

predrill the hole of 35mm diameter with a diameter 80mm hole opening at the bottom, in the 144mm thickness timber panel with an edge distance of 55.5mm,
weld one steel plate 110.1 onto the bottom end of the steel tube 110.2,
install the above welded two pieces 110.1 and 110.2 into the hole of the timber panel 106 from underneath,
predrill the hole of 24mm in diameter in the top flange 104.2 of a steel beam 104,
place the timber panel 106 onto the top flange 104.2 of the steel beam 104,
install the bolt 110.4 into the steel tube 110.2 2 in the timber panel 106 with the 75mm diameter 10mm thick upper steel plate 110.3, the two washers (Pos. 3-1 and Pos. 3-2) and one nut 105, and
apply preload to the bolt 110.5,

The demountable shear connection system is thus installed.

The above-described assembly advantageously occurs without using glue, mortar, grout or any other chemical filler material.

is a sectional view of an assembly 202 according to a second embodiment of the invention.

The reference numbers used in the first embodiment in are used in the second embodiment in for designating the same or corresponding elements, these numbers being however incremented by 100. It is also referred to the description of these elements in connection with the first embodiment.

The assembly 202 of the second embodiment in differs from the one the first embodiment in in that the lower plate 210.1 and the upper plate 210.3 are different in that they both comprise pointed protrusions, i.e. teeth, extending towards the corresponding one of the first slab 206 and the second slab 208, so as to penetrate said slab upon insertion of the tubular spacer 210.2 in the drilling in the slab and upon tightening of the nut 210.5 and the bolt 210.4. The pointed protrusions are distributed evenly at the periphery of the circular lower plate 210.1. The number of pointed protrusions per plate is of at least 10, preferably at least 20. The lower plate with pointed protrusions 210.1 and/or the upper plate with pointed protrusions 210.3 are commercially available as type C11 dowel (system GEKA) or type C1 dowel (system BULLDOG) according to the DIN 1052:2004 norm. The C11 type or GEKA dowel is made of cast iron whereas the C10 or BULLDOG dowel is a stamped and bent plate. It is however understood that other configurations can be considered, including specifically designed configurations that are not yet commercially available.

The assembly 202 of the second embodiment in further differs from the one the first embodiment in in that a support upper plate 210.6 is provided between the head of the bolt 210.4 and the upper plate with the pointed protrusions 210.3. The support upper plate 210.6 is preferably thicker than the upper plate 210.3 with the pointed protrusions and therefore serves as a means for evenly distributing the compressive forces exerted by the bolt 210.4 and the nut 210.5. The commercially available plates with pointed protrusions as described here above usually show a reduced thickness e.g., 3mm for an outer diameter of 80mm, meaning that the support upper plate 210.6 prevents deformation of the upper plate with pointed protrusions 210.3 and a resulting non-uniform distribution of the compressive forces.

The lower plate with pointed protrusions 210.1 does not need a support lower plater as the support upper plate 210.6, because of the rigidity of the upper flange 204.2 of the beam 204. However, in situations where the flange underlying the slab would provide a reduced rigidity, a support lower plate, similar or even identical to the support upper plate, can be provided between the lower plate with pointed protrusions 210.1 and the flange 204.2.

As in the first embodiment, the tubular spacer 210.2 is rigidly fixed to the lower plate with the pointed protrusions 210.1 e.g., by welding, as to form a unitary part that can be inserted into the corresponding drilling from the lower face of the corresponding one of the first slab 206 and second slab 208. Alternatively, the tubular spacer 210.2 and the lower plate with the pointed protrusions 210.1 can be made as a single piece made from the same material i.e., without any mechanical connection provided after manufacturing of the tubular spacer 210.2 and the lower plate with the pointed protrusions 210.1.

In , the lower plate with the pointed protrusions 210.1 is for instance embedded in a corresponding counterbore showing a depth that corresponds to the thickness of said lower plate with the pointed protrusions 210.1, so that the lower face thereof is aligned with the lower face 206.2 or 208.2 of the corresponding one of the first slab 206 and second slab 208. It is however also possible not to provide the counterbore, resulting in the lower plate with the pointed protrusions 210.1 not being embedded or at least not totally embedded in the lower face 206.2 or 208.2 of the corresponding one of the first slab 206 and second slab 208.

The presence of the pointed protrusions on the lower plate with the pointed protrusions 210.1 is particularly useful for distributing shear forces to the slab, in addition to the tubular spacer rigid with said lower plate with the pointed protrusions 210.1.

The upper plate with pointed protrusions 210.3 and the optional support upper plate 210.6 can be replaced by a flat upper plate, as the upper plate 110.3 of the first embodiment or the support upper plate 210.6. The upper plate can have a total thickness (including the optional support upper plate) of at least 8mm and/or at most 12mm.

In an example of the second embodiment, the demountable shear connection system consists of two toothed plates 210.1 and 210.3 of 80mm diameter and 3mm in thickness with central holes of 35mm in diameter, a hot-rolled steel tube 210.2 of steel S355 with an external diameter of 35mm and inner hole diameter of 22mm and 141mm in length, one partially-threaded M20 bolt 210.4 of Gr. 10.9 and of 200mm in length for a 144mm thickness timber slab panel, two M20 washers of Gr. 10.9, one M20 nut 210.5 of Gr. 10.9, and one steel plate 210.6 (with no teeth) of 80mm diameter and 5mm in thickness with a central hole of 22mm in diameter. The steel tube 210.2 is connected with a reinforcing toothed plate 210.1 at the bottom by welding.

The installation of the shear connection is as follows:

predrill the hole of 35mm diameter with an opening of 80mm diameter at the bottom in the 144mm thickness timber panel, with an edge distance of 55mm,
weld one 80mm diameter 3mm thick toothed steel plate 210.1 onto the bottom end of the steel tube 210.2) with teeth facing upwards,
install the above welded two pieces 210.1 and 210.2 into the hole of the timber panel 206 from underneath,
install one 80mm diameter 3mm thick toothed steel plate 210.3 onto the top face of the timber panel 206,
predrill a hole of 24mm in diameter in the top flange 204.2 of a steel beam 204,
place the timber panel 206 onto the top flange 204.2 of the steel beam 204,
install the bolt 210.4 into the steel tube 210.2 in the timber panel 206 with the 80mm diameter 5mm thick upper steel plate 210.3, the two washers (Pos. 3-1 and Pos. 3-2) and one nut 210.5, and
apply preload to the bolt, Pos. 3,

The demountable shear connection system is thus installed.

is a sectional view of an assembly 302 according to a third embodiment of the invention. The cross-section extends along a longitudinal direction of the beam and is therefore perpendicular to the cross-sections of Figures 1 and 2.

The reference numbers used in the first embodiment in are used in the third embodiment in for designating the same or corresponding elements, these numbers being however incremented by 200. It is also referred to the description of these elements in connection with the first embodiment.

The assembly 302 of the second embodiment in differs from the one the first embodiment in in that the lower plate 310.1 is anchored to the slab 306 or 308 by means of two anchoring screws 310.6.1 and 310.6.2 inclined in an opposed manner relative to the longitudinal direction of the fastening kit 310. To that end, the lower plate 310.1 comprises two corresponding anchoring holes 310.1.1 and 310.1.2, each with a main axis that is the main axis of the corresponding anchoring screw 310.6.1 and 310.6.2. For instance, each of the anchoring holes 310.1.1 and 310.1.2 is countersunk so as to form a conical seat for the countersunk head of the corresponding anchoring screw 310.6.1 or 310.6.2. The heads of the anchoring screw 310.6.1 and 310.6.2 are then totally embedded in the lower plate 310.1.

The inclination angle α of the anchoring screws 310.6.1 or 310.6.2 relative to the longitudinal direction of the fastening kit can be of at least 15° and/or at most 45°, preferably of about 30°.

The inclination of the anchoring screws in an opposed manner, for instance in a diverging manner from the lower face 306.2 or 308.2 to the upper face 306.1 or 308.1 of the slab 306 or 308 is advantageous in that it provides a secured anchoring capable of bearing shear forces in various directions, while being very easy to mount and engage into the slab 306 or 308.

Although shows only two anchoring screws, it is understood that more than two such anchoring screws can be provided. For instance, such more than two anchoring screws can be angularly evenly distributed around the longitudinal axis of the fastening kit, being the longitudinal axis of the bolt 310.4.

The lower plate 310.1 can be non-circular e.g., rectangular. As a matter of example, the lower plate 310.1 can be rectangular with a length of 160mm, a width of 75mm and a thickness of 15mm.

As in the previous first and second embodiments, the compression force exerted by the preloading of the bolt 310.4 and nut 310.5 generates important frictional forces between the lower face of the lower plate 310.1 and the upper face of the flange 304.2 of the beam, that are distributed to the slab 306 or 308 in the presence of significant shear forces. It is also clear that the bolt 310.4 can also participate in bearing such shear forces, however when the lower plate 310.1 and/or the tubular spacer 310.2 come in abutment against the bolt 310.4 and the latter comes in abutment against the hole in the flange 304.2 of the beam 304. This is also valid for the previous first and second embodiments.In an example of embodiment 3, the demountable shear connection system consists of, one lower steel plate 310.1 (with no teeth) of 160mm x 75mm x 15mm in size with a central hole of 22mm in diameter and 4 holes of 10mm in diameter, four countersunk screws 310.6 of 120mm in length and installed through the holes of the aforementioned steel plate into the timber panel at an inclination of 60°, a hot-rolled steel tube 310.2 of steel S355 with an external diameter of 35mm and inner hole diameter of 22mm and 129mm in length, wherein the lower plate 310.1 is welded to the bottom end of the steel tube (Pos. 2), one partially-threaded M20 bolt 310.4 of Gr. 10.9 and of 200mm in length for a 144mm thickness timber slab panel, two M20 washers of Gr. 10.9, one M20 nut 310.4 of Gr. 10.9, and one upper steel plate 310.3 (with no teeth) of 75mm in diameter and 10mm in thickness.

The installation of the shear connection according to this example of the third embodiment is as follows:

predrill a hole of 35mm in diameter in the 144mm thickness timber panel 306 with an edge distance of 55mm,
weld the lower steel plate 310.1 of 160mm x 75mm x 15mm onto the bottom end of the steel tube 310.2,
install the above welded two pieces 310.1 and 310.2 into the hole of the timber panel 306 from underneath using the four countersunk screws 306 of 120mm in length at an inclination of 60°,
predrill a hole of 24mm in diameter in the top flange 304.2 of a steel beam 304,
place the timber panel 306 onto the top flange 304.2 of the steel beam 304,
install the bolt 310.4 into the steel tube 310.2 in the timber panel 306 with the upper 75mm diameter 10mm upper thick steel plate 310.3, the two washers and one nut 310.5, and
apply preload to the bolt 310.5.

The demountable shear connection system according to the third embodiment is thus installed.

The present invention further provides a method of fastening a slab 106, 108; 206, 208; 306, 308 to a beam 104; 204; 304 using a fastening kit 110; 210; 310 for instance according to any one of the above embodiments. wherein a slab 106, 108; 206, 208; 306, 308) is positioned onto a beam 104; 204; 304 and the slab is fastened to the beam by using the mentioned fastening kit. The tubular spacer 110.2; 210.2; 310.2 is inserted into the corresponding drilling [hole?] in the slab, from the lower face 106.2; 108.2; 206.2, 208.2; 306.2, 308.2 of said slab, prior to positioning said slab onto the beam. The hole in the beam can be formed prior to positioning the slab on the beam or thereafter. In that latter case, the tubular spacer 110.2; 210.2; 310 can be used as a guide for a drill forming the hole. The slab is then fastened to the beam by inserting the bolt 110.4; 210.4; 310.4 through the central hole of the upper plate 110.3; 210.3; 310.3, the channel of the tubular spacer 110.2; 210.2; 310.2, the central hole of the lower plate 110.1; 210.1; 310.1 and the hole of the beam 104; 204; 304. A nut 110.5; 210.5; 310.5 is then engaged with the inserted bolt and tightened therewith.

Claims

A sub-assembly for fastening a slab (106, 108; 206, 208; 306, 308) to a beam (104; 204; 304), comprising:
a plate (110.1; 210.1; 310.1) with a central hole, for being applied on a lower face (106.2, 108.2; 206.2, 208.2; 306.2, 308.2) of the slab (106, 108; 206, 208; 306, 308);
a tubular spacer (110.2; 210.2; 310.2) designed for full insertion into a drilling in the slab (106, 108; 206, 208; 306, 308) between the plate (110.1; 210.1; 310.1) and an opposed plate (110.3; 210.3; 310.3) with a central hole, for being applied on an upper face (106.1, 108.1; 206.1, 208.1; 306.1, 308.1) of the slab (106, 108; 206, 208; 306, 308);
the tubular spacer (110.2; 210.2; 310.2) having a channel void of inner thread and with an inner diameter that is constant over a whole length of said tubular spacer;
the tubular spacer (110.2; 210.2; 310.2) and the plate (110.1; 210.1; 310.1) being metallic and designed for being engaged through the channel and the central hole by a bolt (110.4; 210.4; 310.4) engaging also a hole in the beam (104; 204; 304);
characterized in that
the plate (110.1; 210.1; 310.1) is permanently linked to a proximal end of the tubular spacer (110.2; 210.2; 310.2) while a distal end of the tubular spacer (110.2; 210.2; 310.2) is free of permanent link to the opposed plate (110.3; 210.3; 310.3) so as to allow insertion of the tubular spacer (110.2; 210.2; 310.2) in the drilling in the slab (106, 108; 206, 208; 306, 308) from its lower face.
The fastening sub-assembly according to claim 1, wherein the plate (110.1; 210.1; 310.1) is circular.
The fastening sub-assembly according to claim 2, wherein the plate (110.1; 210.1; 310.1) has an outer diameter comprised between 50 and 100mm, preferably between 60 and 90mm.
The fastening sub-assembly according to any one of claims 1 to 3, wherein the plate (110.1; 210.1; 310.1) and the tubular spacer (110.2; 210.2; 310.2) show a total length along a longitudinal axis that is comprised between 120mm and 200mm.
The fastening sub-assembly according to any one of claims 1 to 4, wherein the central hole of the plate (110.1; 210.1; 310.1) and an inner diameter of the tubular spacer (110.2; 210.2; 310.2) is of at least 18mm and/or at most 26mm, preferably of 22mm.
The fastening sub-assembly according to any one of claims 1 to 5, wherein the plate (110.1; 210.1; 310.1) shows a thickness of at least 3mm and/or the tubular spacer (110.2; 210.2; 310.2) shows a wall thickness of at least 5mm.
The fastening sub-assembly according to any one of claims 1 to 6, wherein the plate (210.1; 310.1) is provided around the central hole with means (210.1.1; 310.1.1, 310.1.2) for directly anchoring said plate (210.1; 310.1) to the slab (206, 208; 306, 308).
The fastening sub-assembly according to claim 7, the anchoring means on the plate (210.1) comprise pointed protrusions (210.1.1) extending towards the tubular spacer (210.2), so as to penetrate the slab (206, 208) upon insertion of the tubular spacer (210.2) in the drilling in the slab and upon tightening of the bolt (210.4).
The fastening sub-assembly according to claim 8, wherein the pointed protrusions (210.1.1) are evenly distributed around the central hole.
The fastening sub-assembly according to one of claims 8 and 9, wherein the pointed protrusions (210.1.1) are integrally formed with the plate (210.1).
The fastening sub-assembly according to claim 10, wherein the pointed protrusions (210.1.1) and the plate (210.1) form a metallic moulded part.
The fastening sub-assembly according to claim 10, wherein the pointed protrusions (210.1.1) and the plate (210.1) form a stamped and bent metallic part.
The fastening sub-assembly according to any one of claims 7 to 12, wherein the anchoring means on the plate (310.1) comprise anchoring holes (310.1.1, 310.1.2) inclined relative to the longitudinal direction so as to receive anchoring screws (310.6.1; 310.6.2) extending into the slab (306, 308) in a diverging manner relative to said longitudinal axis.
The fastening sub-assembly according to claim 13, wherein each of the anchoring holes (310.1.1, 310.1.2) is countersunk so as to form a conical seating surface for a countersunk head of the anchoring screws (310.6.1; 310.6.2).
The fastening sub-assembly according to one of claims 13 and 14, wherein the inclination of each of the anchoring holes is comprised between 15° and 45°.
A kit (110; 210; 310) for fastening a slab (106, 108; 206, 208; 306, 308) to a beam (104; 204; 304), comprising:
a lower plate (110.1; 210.1; 310.1) with a central hole, for being applied on a lower face (106.2, 108.2; 206.2, 208.2; 306.2, 308.2) of the slab (106, 108; 206, 208; 306, 308);
an upper plate (110.3; 210.3; 310.3) with a central hole, for being applied on an upper face (106.1, 108.1; 206.1, 208.1; 306.1, 308.1) of the slab (106, 108; 206, 208; 306, 308);
a tubular spacer (110.2; 210.2; 310.2) for extending through the slab (106, 108; 206, 208; 306, 308) between the lower plate (110.1; 210.1; 310.1) and the upper plate (110.3; 210.3; 310.3);
a bolt (110.4; 210.4; 310.4) for being inserted through the central hole of the upper plate (110.3; 210.3; 310.3), the tubular spacer (110.2; 210.2; 310.2), the central hole of the lower plate (110.1; 210.1; 310.1) and a hole in the beam (104; 204; 304);
a nut (110.5; 210.5; 310.5) for engaging with the bolt (110.4; 210.4; 310.4) and resting on the beam (104; 204; 304);
wherein the lower plate (110.1; 210.1; 310.1) and the tubular spacer (110.2; 210.2; 310.2) form a fastening sub-assembly according to any one of claims 1 to 15.
An assembly (102; 202; 302) comprising:
a beam (104; 204; 304) with at least one flange (104.2; 204.2; 304.2);
at least one slab (106, 108; 206, 208; 306, 308) positioned against the at least one flange (104.2; 204.2; 304.2);
at least one sub-assembly or kit (110, 210; 310) fastening the at least one slab (106, 108; 206, 208; 306, 308) to the at least one flange (104.2; 204.2; 304.2);
characterized in that
the at least one fastening sub-assembly is according to any one of claims 1 to 15, or the at least one fastening kit (110; 210; 310) is according to claim 16.
The assembly (102; 202; 302) according to claim 17, wherein the at least one slab (106, 108; 206, 208; 306, 308) is made of wood.
The assembly (102; 202; 302) according to one of claims 17 and 18, wherein the at least one slab comprises two slabs (106, 108; 206, 208; 306, 308) arranged side by side on the at least one flange, and several of the at least one fastening sub-assembly or kit (110; 210; 310) fastening each of the two slabs (106, 108; 206, 208; 306, 308) to the at least one flange (104.2; 204.2; 304.2).
A method of fastening a slab (106, 108; 206, 208; 306, 308) to a beam (104; 204; 304), comprising the steps:
positioning the slab (106, 108; 206, 208; 306, 308) onto the beam (104; 204; 304);
fastening the slab (106, 108; 206, 208; 306, 308) to the beam (104; 204; 304) using at least one fastening sub-assembly or kit (110; 210; 310);
characterized in that
the at least one fastening sub-assembly is according to any one of claims 1 to 15 or the at least one fastening kit (110; 210; 310) is according to claim 16.
The method according to claim 20, comprising the following step prior to the positioning step:
inserting the tubular spacer (110.2; 210.2; 310.2) of the at least one fastening sub-assembly or kit (110; 210; 310) into the drilling in the slab (106, 108; 206, 208; 306, 308) from the lower face (106.2; 108.2; 206.2, 208.2; 306.2, 308.2) of said slab.
The method according to claim 21, wherein the fastening step comprises inserting the bolt (110.4; 210.4; 310.4) through the central hole of the opposed or upper plate (110.3; 210.3; 310.3) and the tubular spacer (110.2; 210.2; 310.2), the central hole of the lower plate (110.1; 210.1; 310.1) and the hole of the beam (104; 204; 304), engaging the nut (110.5; 210.5; 310.5) with the bolt (110.4; 210.4; 310.4) so as to rest on the beam, and tightening the bolt and nut.
The method according to any one of claims 20 to 22, wherein the hole in the beam (104; 204; 304) is formed prior to the positioning step or after the positioning step using the tubular spacer (110.2; 210.2; 310.2) as guide for a drill.