EP2412885A1 - Wooden building structure with several storeys - Google Patents

Abstract

The structure (1) has a table formed of a wooden panel (2) including solid wood boards stacked in layers crossed at 90 degrees and stuck structurally between them on surfaces. A lower face (4) of the table forms a ceiling of room of a stage, and an upper face of the table forms a base of the ceiling of the room of another stage. Wooden ribs (8) are structurally secured to an upper face of the panel, and an upper part of the ribs determines a plane (alpha). A load of granular material (10) is placed in intercalary spaces determined by the upper face and opposite faces of surrounding ribs. The ribs are formed of material selected from solid wood, jointed solid wood, laminated wood. The granular material is selected from gravel, mineral granulates e.g. sand, industrial wastes e.g. slag and crushed concrete. A space between the granular material and the plane is filled with an acoustic quality material chosen from mineral wool, felt and polyethylene terephthalate (PET) cotton wadding.

Description

Field of the invention

The invention relates to a new type of structure for multi-storey buildings mainly made of wood, with improved mechanical, thermal and especially acoustic properties.

Because of its excellent acoustic qualities, the structure of the invention is particularly applicable to the construction of collective multi-storey residential buildings.

State of the art

The problem faced by the architect when considering the construction of a building, and particularly wood, is that he is confronted with contradictory criteria: the price of the land often imposes a construction in height, more sensitive to the wind and external solicitations. It requires a stable and rigid structure. But a rigid structure is a headache in terms of acoustic comfort (the propagation and especially the attenuation of structural noise).

In addition, seismic standards, which legislators tend to broaden the scope of application, encourage the design of light structures whose assemblies are both resistant and able to absorb energy.

The energy balance requires a strong insulation of the outer envelope, which implies the use of insulating materials, quite light almost by definition, while inside the building it is preferable to have a mass with high inertia thermal (point low for wooden constructions) to ensure comfort in summer.

Acoustic comfort, on the other hand, would require heavy or non-rigid structures, with continuity solutions attenuating the power of the vibratory waves through the junctions thus created (The vibratory weakening index through a junction is translated by the index K _ij ). We seek here to limit the transmission of noise from one room to another.

Finally, for the serviceability and the limitation of the deformation, the stability of the floors imposes a rigidity with a sufficient eigen mode, to ensure a good mechanical vibratory comfort (to limit the rebound effect of the floors).

More and more severe European standards frame these different criteria. The architect is therefore obliged to juggle contradictory and even contradictory criteria, so as to obtain the "least bad" possible solutions according to the desires of his clients.

Acoustically, the architect has formulas that take into account laboratory values (R _w , L _nT , _w ) that essentially reflect direct transmission through the main wall compositions. The calculations thus made reflect, in practice, rarely the reality, sign of a deep misunderstanding of the factors related to the indirect transmission of acoustic energy to the right of the junctions (the modeling of these factors is still poorly controlled for the constructions in wood).

The problem is that these values do not reflect the "acoustic impedance" of complex structures, material assemblies (cavities, change of environment at junctions, etc.) and therefore requires either extremely complex calculation methods or prediction formulas that are still difficult to master at the current stage of research, or expensive empirical tests (and often a combination of both).

Wood constructions, regardless of their quality in other respects, are considered by poor construction workers as poor parents with regard to acoustic performance compared to traditional masonry constructions.

The document US 5,685,124 describes high load capacity wood panels with good thermal and acoustic properties, especially for the construction of multi-storey buildings.

The panels of US 5685124 consist of ribs arranged in sawtooth, sandwiched between plywood panels. The triangular section volumes determined by these ribs are filled on the one hand with thermal insulation and on the other hand with a heavy load, in particular gravel, intended to improve the acoustic insulation.

GB 1103853 discloses similar structural panels which comprise two outer plates between which a solid granular filler of high specific gravity and an elastic intermediate layer of sound insulation are inserted.

US 5205091 does not relate to wood structures but describes the use of a damping layer, which may be granular, arranged below tiled floors in multi-storey buildings to reduce impact noise transmissions to through these floors.

Summary of the invention

An object of the invention is to promote a prefabricated wooden construction system meeting the acoustic performance requirements between housing, without the use of wall lining.

Another object of the invention is that this system allows rapid erection height over several floors and can use prefabrication, so as to reduce the cost.

Another object of the invention is the construction of wooden buildings meeting the requirements of stability, rigidity and strength required in seismic zones.

Another object of the invention is to be able to make large premises, with, in particular, bearing free floor areas up to 7 m.

Another object of the invention is the placing on the market of buildings with a low ecological impact.

Another object of the invention is the development of a compact wooden structure, to make the most of the volume of living rooms and to benefit from the aesthetic appearance of natural wood.

Another object of the invention is to promote an improvement in the energy performance of buildings both in summer and in winter.

• une table constituée d'au moins un panneau en bois composé de planches en bois massif empilées en couches croisées à 90° et collées structurellement entre elles sur toute leur surface (dit panneau contre-colle, ou lamellé-collé), la face inférieure de cette table formant le plafond d'une pièce d'un premier étage ; la face supérieure de cette table constitue la base d'un plancher d'une pièce d'un étage supérieur au premier étage ;
• une pluralité de nervures en bois de section étirée vers le haut sont solidarisées structurellement à la face supérieure de cet au moins un panneau. L'ensemble [panneau plus nervure] forme une structure autoportante de type ouvert. La partie supérieure de ces nervures détermine un plan α.
• une charge de matériau granulaire est placée dans les volumes intercalaires déterminés par la face supérieure du au moins un panneau et les faces en regard de deux nervures avoisinantes.

The object of the invention is a building structure with essentially wooden floors that includes.

• a table consisting of at least one wooden panel composed of solid wood planks stacked in layers crossed at 90 ° and bonded structurally to each other over their entire surface (so-called anti-glue or glue-laminated board), the lower face of this table forming the ceiling of a room of a first floor; the upper face of this table constitutes the base of a floor of a room of a floor higher than the first floor;
• a plurality of wooden ribs of upwardly stretched section are structurally secured to the upper face of this at least one panel. The whole [panel plus rib] forms an open-type freestanding structure. The upper part of these ribs determines a plane α .
• a load of granular material is placed in the intermediate volumes determined by the upper face of the at least one panel and the opposite faces of two neighboring ribs.

The advantage of such a structure lies first and foremost in its simplicity. Some of the structural elements that constitute it can be prepared in the workshop. On-site assembly is extremely simple and has a limited number of seals (considering the large size of the table).

The presence of granular material gives the structure a high thermal inertia ideal for the comfort of the inhabitants in summer.

The ribs are advantageously made of a material selected from [solid wood, solid butted wood, engineered wood, glue-laminated wood, reconstituted wood].

The ribs are preferably structurally fixed to the wood panel by gluing, so that the contact surface provides cohesion of the panel + rib composite section and thus increases the mechanical inertia characteristics of the panel. If necessary, this collage may be replaced or supplemented by mechanical fasteners such as screws, tips, pins, etc. possibly sealed to the resin.

The degree of filling in granular material of the intermediate volume between two ribs is advantageously between 20 and 100%; it is preferably greater than 80%.

The volume possibly remaining between the granular material and the plane determined by the upper face of the ribs is preferably filled with an acoustic-quality material chosen from [mineral wool, felt, cotton wool or the like and their mixture ].

The granular material preferably has a low absoption rate of moisture, a specific particle size of between 1 and 8 mm, a material or a package which limits its moisture content to 15% and a density of between 1100 and 1700 kg / m ³ .

The granular material is advantageously chosen from [gravel, mineral aggregates such as sand, industrial residues such as clinker, crushed concrete].

The plane α determined by the upper face of the ribs is advantageously surmounted by a floating slab, a layer of resilient material being interposed between this plane and the floating slab.

According to an advantageous embodiment, the building structure comprises at least one vertical wall essentially made of wood, these walls being fixed by an attachment means in line with one of the ribs lining the table. A trim panel (made of wood or other material), peripheral to the table, is disposed under the end face of this at least one wall and extends horizontally on the upper face of the ribs on a width corresponding at least to the distance separating two of these ribs. A resilient seal is disposed between the trim panel and the rib to which the at least one vertical wall is attached.

According to another advantageous embodiment, it comprises at least one vertical wall essentially made of wood that goes lower than the plane α, and is fixed by a fastening means to a rib edge disposed flat on the side of the table. The volume contiguous to this ridge and at the foot of the wall is filled with a mass of granular material. A resilient seal is disposed between the at least one vertical wall and the ridge rib to which it is attached.

According to a preferred embodiment, the at least one vertical wall consists of laminated panels or timber framing panel.

According to an advantageous embodiment, the fastening means is an L-shaped bracket, at least one of the wings of this bracket having perforations surrounded by a conical bevel, this wing being fixed to the structure by means of screws or bolts. conical head of corresponding dimensions, a washer of resilient material being interposed between the chamfer and the head of these screws or bolts, so as to decouple acoustically, the other wing of this bracket being fixed to the table.
According to another advantageous embodiment, the fixing means comprise a plurality of blind holes formed horizontally in the thickness of a vertical panel, near its base, a vertical through hole connecting the base of each of these blind holes and the underside of the vertical panel. The height of a blind hole corresponds substantially to the length of a lag bolt introduced into the through hole and screwed into a rib. An anti-vibratory tip of resilient material is inserted between the head of the lag bolt and the inner wall of the through hole, thereby acting as an acoustic stabilizer.

The panel forming the table preferably has a thickness of at least 95 mm (depending on the loads to be resumed, it can however go down to values of the order of 60 mm). One of the advantages of this relatively large thickness is that the burning of the wood only affects its lower surface layers, without impairing the ability of the whole to support its load. Another advantage of this relatively large thickness, which combines with the large width of the elements of the table, is that the assembly [ribs + panel] has de facto excellent characteristics of structural inertia, which contributes to its strength. efficiency.

According to an advantageous embodiment, dividing walls separate two contiguous rooms A and B, each of these rooms having its own horizontal structure, distinct vertical walls, means of assemblies and separate floating screeds. An anchoring bracket fixed on the one hand to the edge rib of one of the parts, on the other hand to the upper vertical wall of the other part provides the mechanical attachment and vibration cut of these two structures.

Brief description of the figures

La Fig.1

est une vue schématique en coupe des différents modes de propagation de l'énergie acoustique entre deux pièces contiguës ;

La Fig.2

est une vue en coupe verticale, d'un complexe de plancher d'une structure suivant l'invention;

La Fig.3

est une vue en coupe verticale d'un détail de réalisation d'une structure suivant la Fig.2;

La Fig.4

est une vue bâtarde (partiellement en coupe verticale suivant un plan perpendiculaire à celui de la Fig. 2, partiellement en perspective) de la structure de la Fig.2 ;

La Fig.5

est une vue en coupe verticale d'une autre forme de réalisation d'une structure suivant l'invention;

La Fig. 6

est une vue bâtarde (partiellement en coupe verticale suivant un plan perpendiculaire à celui de la Fig.5, partiellement en perspective) d'une structure suivant l'invention ;

La Fig.7

est une vue en coupe verticale d'un détail de réalisation d'une structure suivant la Fig.5;

La Fig.8

est une vue en coupe verticale d'une autre forme de réalisation d'une structure suivant l'invention;

La Fig.9

est une vue en coupe verticale d'une cloison mitoyenne d'un bâtiment suivant l'invention;

La Fig.10

est une vue en coupe verticale d'un détail de réalisation d'un assemblage antivibratoire paroi inférieure/plancher d'un bâtiment suivant l'invention;

Les Fig. 11 et 12

sont des vues en coupe verticale, respectivement de profil et de face, d'une autre forme de réalisation d'une structure suivant l'invention;

These and other aspects of the invention will be clarified in the detailed description of particular embodiments of the invention, reference being made to the drawings of the figures, in which.

Fig.1

is a schematic sectional view of the different modes of propagation of acoustic energy between two adjoining rooms;

Fig.2

is a vertical sectional view of a floor complex of a structure according to the invention;

Fig.3

is a vertical sectional view of a detail of embodiment of a structure according to the Fig.2 ;

Fig.4

is a bastard view (partially in vertical section along a plane perpendicular to that of the Fig. 2 , partially in perspective) of the structure of the Fig.2 ;

Fig.5

is a vertical sectional view of another embodiment of a structure according to the invention;

Fig. 6

is a bastard view (partially in vertical section along a plane perpendicular to that of the Fig.5 partially in perspective) of a structure according to the invention;

Fig.7

is a vertical sectional view of a detail of embodiment of a structure according to the Fig.5 ;

Fig.8

is a vertical sectional view of another embodiment of a structure according to the invention;

Fig.9

is a vertical sectional view of a partition of a building according to the invention;

Fig.10

is a vertical sectional view of a detail of embodiment of an antivibration assembly lower wall / floor of a building according to the invention;

Figs. 11 and 12

are views in vertical section, respectively of profile and face, of another embodiment of a structure according to the invention;

The figures are not drawn to scale.
Generally, similar elements are denoted by similar references in the figures.

Detailed description of particular embodiments

The structure of the invention is a coherent overall approach to economically and simply regulate the safety and comfort of the occupants.

The Fig. 1 schematically shows the different modes of propagation of acoustic energy between two parts separated by a wall. The direct transmission (arrow A) is directly through the partition wall. It is observed that a significant part of the energy is propagated by indirect transmission, via the side walls (arrows B1, B2, B3). Finally, some of the energy is spread by air (parasitic transmission, arrow C). The junction between the walls (dotted circle K _ij ) therefore plays an important role.

The transmission of waves via the side walls for a type of junction considered, requires in-depth research on the index K _ij of each of the 3 indirect transmission channels (B1, B2, B3). These are the latter that drop the effective acoustic performance of a construction, measured in situ, compared to its apparent performance, measured in the laboratory.

In residential wood construction, the practical tests of noise insulation between dwellings show that, on average, we rarely exceed a value D _nT , _w of 40 dB. It is therefore difficult to imagine that we can achieve without walls the isolation values of 54 dB in airborne noise imposed by standards for comfort described as "normal" from one apartment to another. Indeed, we know that doubling the mass of wall components increases attenuation by only 4 dB!

In addition, there are the requirements for standard acoustic insulation for impact noises. Indeed, the transmission of shocks through solid materials is 10 ⁶ times greater than for airborne noise.

To try to meet the new standards, traditional solutions, without worrying too much about lateral transmissions at the junctions, are based on a mass-spring-mass or mass-air-mass concept, which involves the doubling of all the walls of the premises. transmitter and receiver, according to the principle "box in the box", which is expensive, binding (significant loss of space) and potentially gives rise to many defects (we must therefore use a hand of very skilled work). In addition, the wooden structure is hidden, we lose the very warm and decorative atmosphere provided by the use of wood.

The properties of the structure of the invention are based firstly on the structure of the element separating two stages (table 1), which assumes both the function of ceiling (for a lower stage) and of the floor (for an upper stage) - These two names can be used interchangeably in the description below - and on the other hand on the connecting elements between the different parts.

The Fig.2 shows, in section, an embodiment of a horizontal structure 1 (ceiling / floor) of a building according to the invention.

The lower part of this structure 1 is a table formed by a panel 2 consisting of solid wood planks stacked in crossed layers at 90 ° and stuck together structurally between them over their entire surface (said laminated panel), the lower face 4 forms the ceiling of a first room or a first floor. This panel 2 is secured, at its upper face 6, to a series of wooden ribs 8 (seen here end). This joining is preferably done by gluing-pressing, so that the assembly [panel 2 + rib 8] reacts as a single structure, which increases the structural inertia.

The use of panels made of solid wood planks stacked in crossed layers as described above, precisely because of the cross-orientation of the fibers that constitute it, makes it possible to take up both longitudinal and transverse stresses, so that the this provides a structure that can cover very large areas (by multiple 2.4 m floor width) without risk of abnormal deformation and in compliance with the eigenmode imposed for stability to vibration. The interval between two ribs 8, adapted according to the intended range, is filled with granular material (here, gravel) over a certain height, which can go up to the total height of the ribs 8.

As an illustration, we have shown on the Fig. 2 different heights of filling, but it goes without saying that in practice, the same height is generally respected in a given floor. This height varies from 20% to 100%, and is generally above 80%. We can also alternate the filling heights on two or more ribs.

In practice, the gravel, after spillage, undergoes a certain settlement (generally of the order of 8 to 12%). It is however possible to fill the rejection ribs and to complete the filling after mechanical settlement, according to the requirements to be respected.

The use of gravel has four major advantages: it is a heavy material, which easily absorbs noises and vibrations; it is a material that has a high thermal inertia; it is a discontinuous material, which therefore has a high acoustic impedance; it is finally a material easy to move. It is therefore possible to pass sheaths and conduits without problem, even after the event.

The ribs 8 here have a vertical rectangular section, but one can also consider a horizontal rectangular section, square, I or C, depending on the stresses to resume. The upper face of the ribs 8 determines a plane α, which corresponds to the base of the floor of the room of an upper floor. The possible gap between the gravel and the plane α is filled with a lightweight absorbent material 12, such as rockwool, for example.

It is understood that the ceiling thus formed forms an open structure, which must be able to resume all solicitations (shocks, loads, etc.) from the upper floor. The structure as developed is already extremely rigid, and avoids the trampoline effect, even on large spans.

On the base formed by this structure, one can now install any form of adequate floor. Due to the required performance, a floating floor is generally used. A resilient layer 14 (for example a decoupling felt) is extended along the plane a, so as to cover the gravel. A floating peripheral panel 16 (made of wood, laminated or glue-laminated, OSB panel or the like) of a width permitting to make it rest on the two extreme ribs (8, 24) is extended to form an intermediate layer, above which is placed a resilient layer 18, on which one comes to place the floating screed 20 (which can be dry type or wet), taking care that it is nowhere in direct contact with the supporting structure, which would certainly ruin all the precautions taken at this stage. To this end, the elastic layer 18 rises in plinth 21 along the upper vertical wall 22 to complete the acoustic decoupling. Where appropriate, the floating peripheral panel 16 consists of 2 pieces (as shown in FIG. Fig.2 ) to facilitate the subsequent discharge of gravel.

All the precautions taken so far are aimed primarily (but not exclusively) at preventing the direct propagation of noise and vibration from one floor to another. However, as the extensive research and testing carried out by the inventors has shown, most of the inconvenience associated with the propagation of noise in a building comes mainly from the lateral propagation of the energy generated by the vibrations. lateral propagation can account for up to 2/3 of the energy involved). Efforts have therefore been made to reduce this lateral propagation as much as possible, particularly at the junction between the vertical walls 22 and the horizontal structures 1 (ceilings / floors). We notice at the Fig.2 (and in more detail at Fig.3 ) that the end rib 24 of the horizontal structure 1 has a wider section than the other ribs 8.

This feature strengthens the end of the table and facilitates the installation of fasteners, such as a bracket 26, one of whose wings 28 sits on the surface of the rib 24 projecting inwardly, the other wing 30 being fixed to the upper vertical wall 22.

In order to impede the flow of noise and vibrations, three acoustic "decoupling means" are interposed "in series" between the different parts of the structure, as can be seen in Fig. 3 . First, an absorbent elastic layer 32, placed between the outer rib 24 and the peripheral panel 16, then a decoupling washer 33 (playing a stabilizing role) interposed between the screw head 34 with conical head and the corresponding wing 28 of the bracket 26. A second elastic layer 36 (acting as an acoustic isolator) is disposed between the bracket 26 itself and the peripheral panel 16 of the structure.

The centering of the screws 34 relative to the perforations of the square is an essential element from the point of view of acoustics. Washer 33 provides a welcome centering function for assemblers. The position of the bracket 26 can obviously be reversed, as well as that of the decoupling means 33, 36.

We will be well aware that these different resilient layers must each meet very specific specifications and that their compositions and their mechanical characteristics can vary widely. Among the compositions selected, mention may be made of organic or synthetic felts of different densities, needle felt, rubber (natural or recycled), synthetic materials such as Kevlar, PUR, etc.

An additional resilient seal 38 (optional) is placed in a groove in the peripheral panel 16.

The Fig. 4 shows the structure of a building according to the invention under construction, partly in perspective and partially in section along a plane perpendicular to that of the Fig. 2 . The ribs 8 are here seen longitudinally. A continuous edge piece 40 (shown in perspective) dug with mortises 42 provides both sealing, vertical continuity of the structure, alignment and maintenance of the ends of the ribs 8. It closes the volumes between the ribs where the gravel will subsequently be dumped (usually by pumping).

The brackets 26 are here arranged on the ends of the ribs 8. Note here the presence, here too, of a plate 16 peripheral to the horizontal structure 1, which creates an additional change of medium and leads to a better distribution of energy and a strengthening of the junction.

Tests show that the addition of the peripheral plate 16 and the fact of having positioned the fixing of the vertical wall above the ribs (according to the plane α ) alone produce an attenuation comparable to what would have been obtained. by doubling all the walls (walls and ceiling).

The Fig.5 to 7 show another advantageous embodiment of the connection between a horizontal structure 1 and the facade walls 22.

The end rib 24 of the embodiment shown in FIGS. Figures 2 to 4 here is replaced by a bank rib 44 laid flat. The upper vertical wall 22, slightly elongated with respect to the previous embodiment, rests on this edge rib 44 so as to close the volume for the gravel. Here, depending on the nature and the importance of the forces dimensioning the structure, a conventional square 26 or a reinforced square 46 is used here. Fig. 7 ) a puck of decoupling 33 (playing a stabilizing role) is interposed between the screw heads 34 with conical heads (to bolt) and the corresponding wing of the bracket 26, 46. A second elastic layer 36 (acting as an acoustic isolator) is disposed between the bracket 26, 46 itself and the structure 1. A wooden tongue 48 is disposed between the brackets, so as to facilitate subsequent access to the screws 34 and provide a support for the yoke.

As figured in the top of the Fig. 6 , the brackets 26, 46 are here arranged on the longitudinal edge rib 44 and no longer on the ribs 8.

The brackets 26, 46 being below the floating slab 20, there is obtained a space saving in the horizontal plane: the yoke extends 20, without obstacle, to the vertical wall 22. The resilient plinth 21 interposed between the clevis 20 and the upper vertical wall 22 is extended downward so as to cover the vertical flange 30 of the bracket 26, 46.

The Fig.8 shows, in cross section, an alternative embodiment of the assembly of the structure according to the invention. The table 2 is here fixed to the vertical wall 22 not by brackets, but by a wooden profile (or other similar material) 49 flush with the plane α. Alternately horizontal and vertical perforations enable this profile 49 to be fixed to the edge rib and to the vertical wall by means of lag bolts, screws or other fastening means 50.

• Conventionnel non découplé, de préférence dans le cas d'une fixation haute (sur le plan α) : des équerres en L, éventuellement renforcées et fixées par des pointes torsadées ou des vis à bois en nombre suffisant pour s'adapter aux efforts structurels
• Découplé renforcé : une équerre en L de préférence renforcée, au moins une des ailes de cette équerre présentant des perforations entourées d'un chanfrein conique, cette aile étant découplée du bois par un joint résilient structurel « isolateur » et fixée à la structure par l'intermédiaire de vis ou boulons à tête conique de dimensions correspondantes. Une rondelle en matériau résilient, faisant office de stabilisateur, est interposée entre le chanfrein et la tête conique de ces vis ou boulons, de façon à les découpler acoustiquement. Le chanfrein peut être réalisé de différentes façons, notamment par usinage, emboutissage ou par bouterolage. Il contribue notamment au centrage des vis ou boulons. Ce centrage revêt une grande importance pour le découplage acoustique.
• Découplé à tire-fonds : une équerre en L de préférence renforcée, au moins une des ailes de cette équerre présentant au moins un trou plus large permettant le placement d'une rondelle résiliente d'isolation entre le tire-fond et l'équerre. Cette rondelle résiliente (de préférence à base de kevlar ou équivalent) assurera la reprise des efforts parallèles à cette au moins une des ailes et selon la nature et l'importance des efforts dimensionnant la structure. Au dessus et en dessous de cette rondelle d'isolation et prenant appui de part et d'autre de cette au moins une aile sont placés respectivement un stabilisateur situé sous une rondelle métallique (elle-même située sous la tête du tire-fond) et en dessous entre cette au moins une aile et le bois est placé un joint résilient structurel assurant un rôle d'isolateur acoustique.

It has thus been seen that the means for fixing the vertical walls are generally of 3 types.

• Conventional non decoupled, preferably in the case of a high fixation (on the plane α): L-shaped brackets, possibly reinforced and fixed by spikes twisted or wood screws in sufficient number to adapt to structural efforts
• Decoupled reinforced: an L-shaped bracket preferably reinforced, at least one of the wings of this bracket having perforations surrounded by a conical chamfer, this wing being decoupled from the wood by a structural resilient seal "isolator" and fixed to the structure by the intermediate screws or bolts with conical head of corresponding dimensions. A washer of resilient material acting as a stabilizer is interposed between the chamfer and the conical head of these screws or bolts, so as to decouple acoustically. The chamfer can be made in different ways, including machining, stamping or burring. It contributes in particular to the centering of the screws or bolts. This centering is of great importance for acoustic decoupling.
• Decoupled lag screw : an L-shaped bracket preferably reinforced, at least one of the wings of this bracket having at least one wider hole allowing the placement of a resilient insulation washer between the lag bolt and the square. This resilient washer (preferably based on Kevlar or equivalent) will ensure the recovery of parallel forces to this at least one of the wings and according to the nature and importance of efforts sizing the structure. Above and below this insulating washer and supported on either side of this at least one wing are placed respectively a stabilizer located under a metal washer (itself located under the head of the lag bolt) and below this at least one wing and the wood is placed a structural resilient seal providing an acoustic isolator role.

The Fig. 9 is a sectional elevation of a dividing wall separating two rooms of the same floor. All components of an exterior wall assembly (as described in Fig. 2 to 8 ) are here. However, the acoustic problem is complicated by the need to attenuate the noise and vibrations passing between two adjacent rooms. It is no longer possible to use a "simple" sign, otherwise you will get highly degraded results. This problem is solved by uncoupling parts A and B between them: each has its own horizontal structure 1A and 1B, separate vertical walls 22A and 22B, means of assemblies and separate floating screeds. A layer of light resilient material 52 acoustically separates the two structures thus contiguous. The mechanical anchoring by anchoring of these two structures (without degradation of acoustic performance) is obtained by fixing a bracket 53 (preferably reinforced) on the one hand to a rib 24B of one of the parts (here piece B), on the other hand to the upper vertical wall 22A of the other room using lag bolts 55.

Depending on the results to be obtained, that is to say according to the standard of comfort that applies, it is also possible, as shown for part B, to double at least on one side the wall of a wall conventional anti-noise consisting of gypsum board 54 or fibroplâtre fixed by resilient profiles 56 and separated from the vertical wall 22 by a vacuum of about 20 mm.

The performance of this noise barrier is improved if care is taken to reverse this doubling from one floor to another (as shown in FIG. Fig.9 ).

The Fig. 10 shows a form of connection between the panel 2 of the table 1 and the lower vertical panel 22 corresponding with the help of a lag bolt 58. It is obviously necessary to ensure here also an acoustic decoupling between the two elements 2, 22 inferior. For this purpose, the lag bolt 58 is inserted into a through-hole 60 with a diameter much greater than that of the rod 61 of the lag bolt 58. Decoupling and centering are provided on the side of the head of the lag bolt 58. a cylindrical stabilizing tip 62 of resilient material whose lower surface is slightly conical, and the side of the rod 61 by another endpiece or an O-ring 64. A rigid assembly is thus obtained without any acoustically detrimental contact. between the panel 2 and the lag bolt 58. A resilient isolator seal 66 is interposed between the panel 2 and the top of the vertical panel 22. A ceiling angle profile (not shown) can, if necessary, subtract this seal 66 at the sight of the users.

The Fig. 11 and 12 show another method of assembly between a rib 8 of the table 1 and an upper vertical panel 22. A blind hole 68 is formed (generally by ripping) in the thickness of the vertical panel 22, near its base. A through hole 70 connects the base of this blind hole 68 and the underside of the panel 22. The height of the blind hole 68 corresponds substantially to the length of a lag screw 72, which allows the introduction of this lag screw. 72 in the through hole 70 and its screwing into the rib 8. The diameter of the lag bolt is chosen according to the stresses to be resumed. A tip of resilient material 74 is inserted between the head 75 of the lag bolt 72 and the inner wall of the through hole 70, thereby acting as an acoustic stabilizer and centering. The head 75 of the lag screw has a slight taper so as to favor the centering of the rod in the through hole 70. Fig. 10 , the hole 70 has a diameter substantially greater than that of the rod of the lag bolt 72. A thrust washer 76 (optional) (shown in FIG. Fig. 12 ) makes it possible to distribute the loads on a larger surface of wood. Furthermore, since the fastener is closer to the axis of the panel 22 (and / or the axis of a support column), the reversal torque of the panel 22 is more symmetrical. The presence of the assembly is hidden by a plinth 78 or a decorative panel. It is therefore possible to control the state of fixation after an earthquake.

It will be apparent to those skilled in the art that the present invention is not limited to the examples illustrated and described above. The invention comprises each of the novel features as well as their combination. The presence of reference numbers can not be considered as limiting. The use of the term "includes" in no way excludes the presence of other elements other than those mentioned. The use of the definite article "a" to introduce an element does not exclude the presence of a plurality of these elements. The present invention has been described in relation to specific embodiments, which have a purely illustrative value and should not be considered as limiting.

Claims (16)

Staircase structure essentially made of wood characterized in that it comprises - A table (1) consisting of at least one wooden panel (2) made of solid wood planks stacked in a 90 ° cross layer and bonded structurally to each other over their entire surface, the lower face (4) of this table (1) forming the ceiling of a room of a first floor, the upper face of this table (1) constituting the base of a floor of a room of a floor higher than the first floor; a plurality of wooden ribs (8) structurally secured to the upper face of this at least one panel (2), the assembly (panel (2) plus rib (8)) forming an open-type freestanding structure, the part upper of these ribs (8) determining a plane (α); - A load of granular material (10) placed in the intermediate volumes determined by the upper face of the at least one panel (2) and the facing faces of two neighboring ribs (8). Building structure according to claim 1, characterized in that the ribs (8) consist of a material selected from [solid wood, solid buttwood, engineered wood, glue-laminated wood, reconstituted wood]. Building structure according to any one of claims 1 or 2, characterized in that the ribs (8) are fixed to the table (1) by pressing and gluing. Building structure according to any one of claims 1 to 3, characterized in that the filling rate of granular material (10) of the intermediate volume between two ribs (8) is between 20 and 100%. Building structure according to Claim 4, characterized in that the filling ratio of the granular material (10) of the intermediate volume between two ribs (8) is greater than 80%. Building structure according to any one of the preceding claims, characterized in that the volume remaining between the granular material (10) and the plane (α) determined by the upper face of the ribs (8) is filled with a material (12). ) of acoustic quality selected from [mineral wool, felt, PET wadding or the like, and mixtures thereof]. Building structure according to one of the preceding claims, characterized in that the granular material (10) has a specific particle size of between 1 and 8 mm and a density of between 1100 and 1700 kg / m3. Building structure according to any one of the preceding claims, characterized in that the granular material (10) is selected from [gravel, mineral aggregates such as sand, industrial residues such as clinker, crushed concrete]. Building structure according to one of the preceding claims, characterized in that the plane (α) determined by the upper face of the ribs (8) is surmounted by a floating yoke (20), a layer of resilient material (18) being interposed between this plane (α) and the floating yoke (20). Building structure according to any one of the preceding claims, characterized in that it comprises at least one upper vertical wall (22) essentially made of wood, this at least one upper vertical wall (22) being fixed by a fixing means ( 26) in line with one of the ribs (8, 24) of the table (1), a trim panel (16) peripheral to the table (1) being arranged under the end face of this at least an upper vertical wall (22) and extending on the upper face of the ribs (8) over a width corresponding at least to the distance separating two of these ribs (8), a resilient seal (38) being arranged between this panel of peripheral plate (16) and the rib (8) to which the at least one vertical wall is fixed. Building structure according to any one of claims 1 to 9, characterized in that it comprises at least one vertical wall essentially made of wood (22), this at least one upper vertical wall (22), descending below the plane (α), being fixed by a fastening means (26) to a ridge rib (44) disposed flat at the end of the table, the volume contiguous to this ridge rib (44) and at the foot of the wall upper vertical (22) being filled with a mass of granular material (10), a resilient seal (38) being disposed between said peripheral trim panel (16) and the edge rib (44) to which it is attached. Building structure according to any one of claims 10 or 11, characterized in that the at least one vertical wall (22) consists of laminated panels or timber framing panel. Building structure according to any one of claims 10 to 12, characterized in that the fastening means (26) is an L-shaped bracket (26), at least one of the wings (28, 30) of this bracket (26) having perforations surrounded by a conical chamfer, said flange (28) being fixed to the structure by means of screws or bolts with conical head (34) of corresponding dimensions, a washer of resilient material (33) being interposed between the chamfer and the head of these screws or bolts (34), so as to decouple them acoustically, the other wing (30, 28) of this bracket being fixed to the table (1). Building structure according to any one of claims 1 to 12, characterized in that the fixing means comprise a plurality of blind holes (68) arranged horizontally in the thickness of a vertical panel (22) near its base. a vertical through hole (70) connecting the base of each of said blind holes (68) and the underside of the vertical panel (22), the height of the blind hole 68 corresponding substantially to the length of a lag bolt (72); ) introduced into the through hole (70) and screwed into a rib (8), a resilient material tip (74) being inserted between the head (75) of the lag bolt 72 and the inner wall of the through hole (72). Building structure according to one of the preceding claims, characterized in that the panel (2) forming the table has a thickness of at least 95 mm. Building structure according to any one of the preceding claims, characterized in that it comprises dividing walls separating two adjoining rooms A and B, each of these rooms having its own horizontal structure (1A, 1B), with distinct vertical walls. (22A, 22B), means of assemblies and separate floating screeds, a bracket (53) fixed on the one hand to one of the ribs (24B) of one of the parts, on the other hand to the vertical wall upper (22A) of the other piece, ensuring the mechanical attachment and decoupling of these two structures.

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