EP2998443A1 - Noise protection wall - Google Patents

Abstract

The present invention relates to a noise barrier (10) comprising acoustic elements (12) and construction elements (14), wherein the phonic element (12) is Z-shaped, and comprises: €¢ two substantially horizontal and parallel acoustic panels (16) comprising a shell (30) having has. an upper side, b. an underside and vs. sound absorbing material €¢ an inclined part (28) has. located between the first acoustic panel and the second acoustic panel b. connecting a rear part of the first acoustic panel to a front part of the second acoustic panel located below the first acoustic panel characterized in that the sloped part (28) consists of a sound-reflecting material, and the shell (30) of the first acoustic panel has openings giving

Description

Technical area

The present invention relates to noise barriers.

State of the art

Noise barriers have been used for a long time along roads, railways, airports etc. to reduce the impact of noise on people living and working near these noise sources.

In the area of noise caused by rail and road traffic, various devices have been put on the market with the aim of contributing to a quieter environment and reducing health problems related to noise. In particular, the noise barriers offer a good enough protection against noise.

The document FR 2,630,762 is more particularly an absorbent screen structure for wall and sound barrier wall covering. This structure consists of a plurality of plates resting on one hand on posts and on the other hand on the wall thus being oriented so as to define with the vertical edge passing through the wall an angle at the vertex between 20 and 40 °. The noise barrier is Z-shaped and consists of two substantially horizontal and parallel acoustic panels 3a comprising a sound absorbing material and a sloping portion absorbing the concrete noise.

The documents WO 95/06167 A1 and FR 2 455 127 A1 both describe a noise barrier with zigzag-shaped elements with noise-reflective elements alternating with noise-absorbing elements.

The document DE 2936776 describes a soundproof wall on which are fixed parallel several rows of horizontal slats, one above the other. The slats are attached to the front of the noise barrier, facing the source of the noise. The protruding slats are inclined downwardly at an angle of about 45 ° to the horizontal and consist of a rigid layer under which is attached a thin layer comprising a sound absorbing material. This thin layer, absorbent, covers not only the underside of the protruding slats but also the front face of the noise barrier, between the slats. The incident sound waves are reflected on the rigid layers, are deflected towards the absorbent layer of the lamella and are then absorbed by the absorbent material of the layer which covers the underside of the lamella and the absorbent material lying on the front of the noise barrier, between the slats. The back side of the wall is smooth and flat.

The document DE 10 2005 055 521 presents a noise barrier similar to that described in the document DE 2936776 . The projecting horizontal slats are inclined downward at an angle of about 30 ° to the horizontal. The space between the projecting horizontal slat and the front of the noise barrier is completely filled by a wedge-shaped noise absorbing member. The absorbent material and the lamellae are made of materials of plant origin.

The document DE 297 06 785 describes a sound barrier with noise protection elements interposed between load-bearing beams. The noise-shielding elements have a non-isosceles prismatic shape, the shorter side of which is shorter, is provided with solar panels and the lower oblique side, the longer side, is provided with a perforated plate and a sound absorbing element arranged behind it. The lower oblique side allows the sound to pass into the prismatic body where it will be reflected on the vertical wall of the prismatic body.

There are numerous products on the market, for example the noise barriers marketed under the trade names "Alumna" and "Tavi" by R. Kohlhauer GmbH of D-76571 Gaggenau.

The operating principle of these noise barriers is that the sound waves penetrate inside a sound-absorbing material where they generate friction, slight movements of fibers, which leads to a transformation of the energy of sound into a friction energy respectively in heat.

These materials have a low absorption coefficient at low frequencies and high at high frequencies. The absorption at low frequencies is all the more important that the material is thick and that its pores or cavities are large. The sound absorbing material is therefore generally a low density material and therefore low mechanical stability. It is usually contained in a load bearing structure that has openings facing the noise source to allow sound waves to penetrate the absorbent material.

Although very effective, these noise barriers have the disadvantage of being opaque, which can create security risks by creating shaded areas. In addition, these noise barriers have a poor aesthetic appearance.

There are also transparent noise barriers. Thus the noise walls "Petra" of the company Postigo and "Acrylite" Armtec company are transparent and the borders can be painted as well as include ornamental and decorative elements. These noise barriers provide increased visual comfort and even have very high noise reflection performance, but have the disadvantage of not achieving noise attenuation performance such as the other noise barriers described above.

Object of the invention

The object of the present invention is therefore to create a sound barrier which avoids the creation of shadow areas and has high noise attenuation performance.

General description of the invention

• deux panneaux acoustiques sensiblement horizontaux et parallèles comprenant une coque ayant
  1. a. une face supérieure,
  2. b. une face inférieure et
  3. c. un matériau absorbant le bruit situé à l'intérieur de la coque
• une partie inclinée
  1. a. située entre le premier panneau acoustique et le deuxième panneau acoustique
  2. b. reliant une partie arrière du premier panneau acoustique à une partie avant du deuxième panneau acoustique situé en dessous du premier panneau acoustique

caractérisé en ce que
la partie inclinée consiste en un matériau réfléchissant le bruit, et
la coque du premier panneau acoustique présente des ouvertures donnant accès au matériau absorbant le bruit uniquement sur sa face inférieure.The present invention relates to a sound barrier comprising acoustic elements and constructive elements,
wherein the sound element is Z-shaped, and comprises:

• two substantially horizontal and parallel acoustic panels comprising a shell having
  1. at. an upper face,
  2. b. a lower face and
  3. vs. a sound-absorbing material located inside the hull
• an inclined part
  1. at. between the first acoustic panel and the second acoustic panel
  2. b. connecting a rear portion of the first acoustic panel to a front portion of the second acoustic panel located below the first acoustic panel

characterized in that
the inclined part consists of a material reflecting the noise, and
the shell of the first acoustic panel has openings giving access to the sound absorbing material only on its underside.

Surprisingly, it has been found that, contrary to what one could believe, it is not necessary to direct the acoustic panels directly in the direction of the source of the noise in order to obtain an attenuation important noise. In this noise barrier, the acoustic panels are horizontal and facing the ground in the case of a source of noise that is in front of the noise barrier. The sound waves emitted by the noise source are deflected on the inclined portion reflecting the sound waves and then enter the acoustic panel through the openings in its lower face, facing the ground. It is interesting to note that there are no sound absorbing elements facing the noise source.

In a particular embodiment, the underside of the acoustic panel is perforated sheet. Preferably the openings are round holes of +/- 4 mm in diameter.

An advantage of practicing the openings in the underside of the acoustic panel and only in it is to protect the sound-absorbing material from the elements. Indeed, as the sound absorbing materials are by their nature porous materials respectively fibrous and low density, they can foul quickly when subjected to the weather. Indeed, in the traditional panels in which the openings are in the vertical face, it is found that the dirty water projected by the traffic against these acoustic panels penetrates and can foul the cavities, stop them as and to reduce and significantly the long-term performance of this kind of panels.

Another advantage of these new phonic elements lies in the fact that they can be transparent and thus contribute to increasing road safety. The creation of shadow areas is avoided. No "tunnel" effect is created and users can contemplate the surrounding landscape. The risks of accidents due to monotonous paths - between two walls - are reduced.

According to a preferred embodiment, the shell of the acoustic panel in which the noise-absorbing material is installed is self-supporting and can be made for example of aluminum. This creates lightweight but strong noise barriers. The aluminum of the acoustic panel shell can be anodized or powder-coated polyester.

Of course, there must be enough openings in the underside of the acoustic panel shell to allow the sound waves to penetrate effectively into the sound absorbing material. According to an embodiment preferred, the underside of the shell of the acoustic panel comprises apertures / perforations which cover at least 35% of its surface.

On the other hand, it is not necessary to leave the bottom face completely open to achieve the required acoustic performance. It is indeed preferable that the underside comprises apertures / perforations which cover at most 80% preferably at most 70, more preferably at most 60% of its surface.

The absorbent material is chosen from the numerous materials available on the market and preferably comprises a melamine resin type foam with or without hydrophobic impregnation, mineral wool, glass wool, rockwool, mineral fibers, fiberglass vegetable origin or mixtures thereof.

The inclined part must deflect the maximum of the incident sound waves towards the acoustic panel situated above it. It preferably comprises laminated glass, safety glass, polymethyl methacrylate, polycarbonate or a combination of these materials. These materials have the advantage of being transparent and allow by their smooth surface to reflect a maximum of incident sound waves to the acoustic panel.

In order to optimize the performance of the noise barrier, the inclination of the inclined portion is generally at least 50 ° and at most 70 ° relative to the horizontal. In this range of inclination angles, a majority of incident sound waves are diverted to the underside of the acoustic panel.

According to a preferred embodiment, the inclined portion comprises a frame and seals to allow to easily fix the inclined portion in the construction and to ensure a perfect seal between the constituent elements.

The building elements preferably comprise metal poles, vertical uprights and frames, as well as fixing accessories necessary for the assembly and mounting of the sound elements. The metal posts serve as a support for the sound elements and are fixed on the concrete foundations. Vertical uprights and frames, made of aluminum for example, serve as holding elements.

Brief description of the drawings

• Fig. 1 : représente une vue frontale d'un mode de réalisation préféré de la présente invention,
• Fig. 2 : représente une coupe selon la ligne A-A de la Fig. 1 et;
• Fig. 3 : représente le mur antibruit vu de dos.

The features of the invention will emerge from the detailed description of some advantageous embodiments presented below, by way of illustration, with reference to the following drawings:

• Fig. 1 represents a front view of a preferred embodiment of the present invention,
• Fig. 2 : represents a section along line AA of the Fig. 1 and;
• Fig. 3 : represents the noise barrier seen from behind.

Description of a preferred execution

The figure 1 shows a view of the front of the modular noise barrier, which is the main receiving side of the noise. The noise barrier 10 is composed of modules comprising phonic elements 12 and constructive elements 14. The sound element 12 is Z-shaped, the inclined portion of which is made of a noise-reflecting material and the horizontal parts of which are acoustic panels. ie d. sound absorbing panels.

The inclined portion of the Z-shaped sound element 12 is located between two substantially parallel acoustic panels 16. It connects the rear part of a first acoustic panel to the front part of a second acoustic panel, located below the first panel to form a shaped element of the letter "Z".

A feature of the present invention is that the acoustic panels 16 have openings providing access to the sound absorbing materials exclusively on the downward facing side. No opening is made in the other sides of the shell so that no sound absorbing material is directed directly to the source of the noise.

The inclined portion 28 of the sound element 12 does not absorb the waves but reflects the incident sound waves and deviates to the acoustic panel above it.

The construction elements 14 comprise metal posts 18, vertical uprights 20 and frames 22, as well as fixing accessories necessary for assembling and mounting the sounding elements 12. The metal posts 18 serve as support for the sound elements 12 and are fixed on the concrete foundations 24. Vertical uprights 20 and frames 22, for example aluminum, serve as holding elements.

The noise barrier 10 of the Fig. 1 comprises 4 rows and 2 columns of sound elements 12. These have for example the following dimensions: height about 480 mm, width about 1500 mm, depth about 290 mm. The noise barrier is composed of modular elements and these elements can be multiplied to obtain a sound barrier of the desired languor and height.

The reflective portion 28 is inclined with respect to the absorbent panel by about 60 degrees, so as to be able to reflect the sound waves converging towards it.

The sound elements 12 are assembled by three vertical uprights 20, two uprights at the front and rear ends respectively of the sound element 12 and an upright being arranged in the middle of the sound element 12. The uprights at the ends allow the sound to be maintained. acoustic screen 10 between the metal posts 18, which are fixed on the foundations 24 of the noise barrier 10. The height of the noise barrier wall 10 is therefore about 2.00 m and the distance between the columns is about 4 , 20 m.

The sound element 12 comprises a self-supporting shell or box 30 and is filled with a sound-absorbing material. The shell 30 is perforated only on its sound-receiving face, i.e. the lower face which is directed towards the inclined portion, located below the shell 30. The perforations cover about 44% of the surface of the receiving face of the shell 30.

The shell 30 is aluminum with a thickness of 2 mm. Aluminum can be anodised or powder-coated polyester in a choice of colors, such as a RAL shade.

The absorbent material may be a melamine resin foam board, of the BASOTECT G type, for example, or a melamine resin foam with a hydrophobic impregnation, such as PINTA Piano foam, with a thickness of about 50 mm. The absorbent material may also be mineral wool, glass wool, rockwool, mineral fibers, plant fibers or other insulation materials. The advantage of using melamine resin results in very good sound absorption, low thermal conductivity, good fire resistance and low density.

The reflective portion 28 is a phonic laminated glass panel. The glass is preferably a transparent safety glass. The laminated glass consists of two 8 mm thick glass sheets glued between which is placed a plastic film of polyvinyl butyral (PVB) with a thickness of 0.75 mm or a standard clear film with a light transmission coefficient greater than 70%. Resistance to impacts of stone and gravel is ensured by the glass.

The material used for the reflective portion 28 may be conventional layered glass (laminated glass), polymethyl methacrylate or polycarbonate or the like. Preferably, glass "Saflex QS 41" Eastman producer is chosen because of its high sound insulation index.

It is therefore a system against noise that is largely transparent, open to view. The incident light is largely transmitted from the other side of the glazing, a portion is reflected and a tiny portion is absorbed. The reflected light is partly projected on the absorbent portion 26 and thus protects against glare.

The frames 22 around the inclined portions 28 are made of aluminum and serve as support for the inclined portions. The frame 22 is provided with a neoprene seal 32 on its periphery to guarantee the stability and the tightness of the sound element 12. A system of glazing beads makes it possible to fix the glass on the frame 22.

In order to guarantee the tightness of the system, a neoprene seal 32 is interposed at the level of the connecting joints between the various constituent elements, in particular between the acoustic panels 16 and the vertical uprights 20.

The metal posts 18 serve as a support and are composed of hollow rectangular metal tubes and have dimensions of approximately 150 mm x 100 mm and a thickness of 4 mm. The metal posts 18 may be S235 steel welded on plates. Each post 18 is an assembly of two half-posts 36, assembled by threaded rods and nuts 38 of stainless steel for holding the phonic elements 12 by pinching. Each half-post 36 is fixed on the foundations 24 by means of anchors, the anchoring devices being in sufficient number per plate 34 as required. A seal 32 is also interposed between each half-post 36 and the uprights 20 of the acoustic screen 10.

The foundations 24 on which the sound barrier wall and which allow the metal poles 18 to be fixed by anchoring are made of reinforced concrete.

The assembly of the various elements constitutes a rigid structure which is able to support its own weight, the thrusts of winds to which it is exposed, the pressures and depressions caused by the passage of the machine (air penetration), thermal expansion, etc. The assembly is, by design, easy to maintain and damaged elements are easily replaceable individually. The tightness of the system contributes to protection against long-term damage and corrosion.

The figure 2 shows a cross section of the noise barrier 10 along line AA of the Fig. 1 . The inclined portion 28, for example a laminated glazing unit, reflects the sound waves and sends them to a large extent to the absorbent material located inside the perforated aluminum shell 30 with a melamine foam.

On the figure 2 , the noise barrier 10 has four rows of phonic elements 12 superimposed.

The figure 3 shows a view of the rear face of the noise barrier 10 .. This face is not intended to absorb noise because it is not directly exposed to noise. Unlike the majority of noise barriers, its surface is not flat but is also Z-shaped due to the fact that for each sound element the reflecting part connects the rear part of a first acoustic element with the front part of a sound element. second acoustic element located below it. On the figure 3 it can also be seen that the upper row is composed of two acoustic panels 16 attached to a continuous element 40 which is connected to the vertical uprights 20 so as to close the top of the noise barrier wall 10.

The present noise barrier 10 has been designed to achieve attenuation of the typical transmission noise spectrum of more than 26dB. Studies carried out in collaboration with the University of Leuven were carried out using an in-situ measurement method at the station Noertzange (LU) according to the method of standard CEN / TS 1793-5. CEN / TS 1793-5 entitled "Noise reduction devices for road traffic. Test method for the determination of sound performance-Part 4: Intrinsic characteristics relating to the in-situ values of acoustic reflection and airborne sound insulation "has been applied to a section of the noise barrier described as in relation to with the figures 1-3 .

Surprisingly, it has been found that the attenuation of noise far exceeds the goal that was set. Thus the noise attenuation measured for the sound element 12 was 28.4 dB and 30.7 dB for the supports / posts 18. With an equivalent weighting procedure for a railway noise, values of 31.4 dB for the sound element and 32.7 dB the supports / posts 18 were obtained. These are mitigation values far above expectations.

The acoustic insulation of the "Z" screen compared to railway noise is superior to the equivalent products existing on the market, reaching values around DLr = 29dB. It should be noted that the existing products on the market have values measured in the laboratory, while the values of the "Z" screen have been measured "in situ".

According to another embodiment, in one or more of the phonic elements, the inclined portion can be made by solar panels. Particularly weather-resistant solar panels, such as in the case of heavy rain and hail, and exposure to salty air or other corrosive atmospheres are preferably used. Solarwatt's solar panels, such as the Solarwatt Blue or Orange types, are particularly suitable for this purpose. The use of solar panels as noise-reflective inclined sections will - when the orientation of the noise-canceling wall in relation to the sun lends itself to it - produce renewable electricity. <B> Title: </ b> 10 Noise barrier 12 phonic element 14 constructive element 16 acoustic panel 18 metal post 20 uprights (vertical) 22 frame 24 foundation 26 absorbent part 28 reflective part (inclined part) 30 shell or box 32 neoprene seal 34 platinum 36 half-post 38 threaded rod and nut 40 continuous element

Claims (12)

Noise barrier wall (10) comprising sound elements (12) and constructive elements (14),
wherein the sound element (12) is Z-shaped, and comprises: Two substantially horizontal and parallel acoustic panels (16) comprising a shell (30) having at. an upper face, b. a lower face and vs. a sound absorbing material • an inclined part (28) at. between the first acoustic panel and the second acoustic panel b. connecting a rear portion of the first acoustic panel to a front portion of the second acoustic panel located below the first acoustic panel characterized in that
the inclined portion (28) consists of a noise-reflecting material, and
the shell (30) of the first acoustic panel has openings giving access to the sound absorbing material only on its underside. Noise barrier (10) according to claim 1, characterized in that the shell (30) is self-supporting. Noise barrier (10) according to any one of the preceding claims, characterized in that the shell is made of aluminum. Noise barrier (10) according to any one of the preceding claims, characterized in that the underside of the shell (30) comprises apertures / perforations which cover at least 35% of its surface. Noise barrier (10) according to any one of the preceding claims, characterized in that the underside of the shell (30) comprises apertures / perforations which cover at most 80% of its surface. Noise barrier wall according to any one of the preceding claims, characterized in that the absorbent material is chosen from a melamine resin type foam with or without hydrophobic impregnation, mineral wool, glass wool, rock wool, mineral fibers , fibers of vegetable origin or mixtures thereof. Noise barrier (10) according to any one of the preceding claims, characterized in that the inclined portion (28) comprises laminated glass, safety glass, polymethyl methacrylate, polycarbonate or a combination of these materials. Noise barrier (10) according to any one of the preceding claims, characterized in that the inclination of the inclined portion (28) is at least 50 ° to the horizontal. Noise barrier (10) according to any one of the preceding claims, characterized in that the inclination of the inclined portion (28) is at most 70 ° to the horizontal. Noise barrier (10) according to any one of the preceding claims, characterized in that the inclined portion (28) comprises a frame. Noise barrier (10) according to any one of the preceding claims, characterized in that the construction elements comprise metal posts (18), vertical uprights and frames for fixing the sound elements (12). Noise barrier (10) according to any one of the preceding claims, characterized in that the noise barrier is modular.

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