Classifications

• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01F—ADDITIONAL WORK, SUCH AS EQUIPPING ROADS OR THE CONSTRUCTION OF PLATFORMS, HELICOPTER LANDING STAGES, SIGNS, SNOW FENCES, OR THE LIKE
  • E01F8/00—Arrangements for absorbing or reflecting air-transmitted noise from road or railway traffic
  • E01F8/0005—Arrangements for absorbing or reflecting air-transmitted noise from road or railway traffic used in a wall type arrangement
  • E01F8/0029—Arrangements for absorbing or reflecting air-transmitted noise from road or railway traffic used in a wall type arrangement with porous surfaces, e.g. concrete with porous fillers

Definitions

• the present invention relates to an acoustic wall.
• noise barriers are erected along roads and railways near residential areas.
• noise barriers are simply walls of sound absorbing panels. These walls must be firmly anchored in the ground. This requires fairly deep foundations, which are expensive and time-consuming.
• the object of the present invention is to provide an acoustic wall which can be erected quickly.
• an acoustic wall characterized by a sheet pile wall comprising at least one crest, a hollow and an oblique part connecting the crest and the hollow; by . sound absorbing panels fixed to said sheet pile curtain and covering at least partially one face of said sheet pile curtain, said sound absorbing panels being arranged so as to cover at least two of said hollows, crest and oblique part.
• This kind of acoustic wall is implemented quickly; in fact, it suffices to drive in sheet piles and to fix acoustic absorbing panels on all or part of one face of the sheet pile wall.
• the sheet pile support wall can be made of either cold-rolled or hot-rolled sheet piles.
• the sheet pile curtain can also serve as a retaining wall for the site.
• An acoustic wall comprising sheet piles is therefore an advantageous alternative to traditional methods which consist erecting noise barriers in front of retaining walls. This then provides a retaining wall with considerably better noise reduction properties than those of the retaining walls usually arranged along roads and railways. The addition of an additional noise barrier becomes unnecessary.
• acoustic absorbing panels cover p. ex. the hollow, the oblique part and possibly the crest of one face of the support wall.
• the acoustic absorbing panels are preferably arranged so as to completely cover one face of the support wall: the ridges, the hollows and the oblique parts. A very good acoustic absorption performance is thus obtained. In addition, since one face is entirely covered with sound absorbing panels, it is not necessary to apply an anti-corrosion protection to the face of the support wall on which the panels are fixed.
• a space is arranged separating the part of the sound absorbing panel located in the hollow, from the bottom of the latter.
• the other part or parts of the panels is (are) fixed directly against the surface of the support wall.
• the space thus formed acts as an absorption cavity which improves the acoustic absorption performance of the support wall.
• the depth of the absorption cavity is between 50 mm and 250 mm.
• the sound absorbing coating can consist of a juxtaposition of flat panels cut to size and fixed directly to the sheet pile wall.
• an absorbent panel molded in the shape of a "U” is used so as to reproduce the corrugated shape of the sheet pile wall.
• Such an acoustic absorbing panel makes it possible to cover both a ridge and the two adjacent oblique parts. This allows faster and easier installation of the acoustic absorbing panels on a sheet pile curtain.
• connection piece can be used at the hollow to connect a U-shaped panel to a neighboring U-shaped panel.
• This connecting piece is preferably a piece of sound absorbing material and therefore makes it possible, in conjunction with the 'U' panel, to cover a support wall over an entire face with an acoustic absorbing coating.
• a space is formed between the support wall and the sound absorbing coating at the level of the recesses and / or oblique parts.
• the space thus formed acts as an absorption cavity which improves the acoustic absorption performance of the support wall.
• the acoustic U-shaped absorbing panels and the connecting pieces are preferably standardized. This implies that only one type of panels and one type of connecting pieces can be used on various types of sheet piles.
• the sound absorbing panels can be fixed to the sheet pile wall with suitable nails.
• brackets can be used which can be directly nailed to the support wall. This allows rapid and easy installation of acoustic absorbent panels.
• the present invention relates to all types of sound absorbing material which can be in the form of panels or can be fixed on a rigid support such as a metal sheet (for example a sheet covered with rock wool).
• the acoustic panels are preferably made of fine and long fibers of mineralized resinous wood and coated with a lime / cement binder. Preferably, these panels have a thickness of between 25 mm and 100 mm.
• the assembly formed by the sheet pile curtain and the absorbent covering acoustic is preferably covered on its upper end by a crowning piece. This crowning piece acts as a 'roof', protecting the space between the sheet pile wall and the sound absorbing coating against the weather. This ensures greater longevity of the acoustic wall.
• Fig.1 Sectional view of a sheet pile wall covered with sound absorbing panels
• Fig. 2 Sectional view of several embodiments (a, b, c, d, e).
• Fig. 3 Sectional view of a sheet pile wall covered with acoustic U-shaped panels
• Fig. 4 Sectional view of a sheet pile wall of various types covered with acoustic U-shaped panels a) sheet piles types PU 6 to PU 32 b) sheet piles type AZ 13 c) sheet piles type AZ 18, AZ 26, AZ 36 d) sheet piles type AZ 48
• Fig. 5 Sectional view of a connecting piece
• Fig. 6 Sectional view of a crowning piece
• the acoustic wall 10 shown in FIG. 1 comprises several sheet piles 12 interlocked with one another by their claws to form a sheet pile curtain.
• the sheet pile wall comprises a succession of ridges 14, hollows 16 and oblique portions 18 connecting a crest and a hollow.
• Acoustic absorbent panels 20 directly cover the ridges and oblique parts.
• the sound absorbing panel located in the hollow is fixed parallel to each hollow of the sheet pile wall, of so as to arrange an air space forming an absorption cavity 22 between the bottom of the hollow of the sheet pile and the sound absorbing panel.
• a measurement campaign was carried out to test the performance of materials and different embodiments.
• Acoustic absorbent panels marketed under the name FIBRACOUSTIC ALPHA by the firm KNAUF ISOL-PACK, with a thickness of 75 mm, were used. Acoustic performance was measured in a reverberating room of 190 m 3 and 200 m 2 .
• the acoustic performance of a 12 m 2 sound absorbing panel, laid flat directly on the ground in the center of the reverberation chamber was measured in accordance with standards EN 20354 and ISO 11654.
• a result of ⁇ L ⁇ 9 dB was obtained and allows classifying the sound absorbing panel in class A3 of standard EN 1793-1.
• Figure 2-A shows the arrangement used in test A.
• the ridges are covered.
• the acoustic absorbing panels are fixed so as to provide an air space forming an absorption cavity 130 mm deep.
• Figure 2-B shows test B.
• the ridges are covered.
• the acoustic absorbing panels are fixed so as to provide an air space forming an absorption cavity 130 mm deep.
• the oblique parts are covered on the surfaces which extend between the absorbent panels placed above the hollows and the edges of the ridges.
• FIG 2-C is illustrated the test C.
• the ridges are not covered.
• the acoustic absorbing panels are fixed so as to provide an air space 130 mm deep.
• the oblique parts are covered on the surfaces which extend between the absorbent panels placed above the hollows and the edges of the ridges.
• Figure 2-D shows test D.
• the ridges are covered.
• the acoustic absorbing panels are fixed so as to provide an air space 130 mm deep. Every other oblique part is covered on the surfaces which extend between the absorbent panels placed above the hollows and the edges of the ridges.
• Figure 2-E shows the test E.
• the ridges and the oblique parts are covered.
• the hollows are not covered.
• the recesses are never in direct contact with absorbent panels.
• the linear surface of the sheet pile wall tested was 10.74 m 2 and the developed surface was 14.94 m 2 .
• the EN 1793 standard allows acoustic materials to be classified in several categories, according to their overall sound absorption index ⁇ L ⁇ .
• Class A3 contains “very absorbent” products for which 8 ⁇ L ⁇ ⁇ 11 dB.
• the class containing the best performing products is class A4, for which ⁇ L ⁇ > 11 dB.
• Tests show that it is not necessary to cover the entire surface of the support wall with sound absorbing panels to obtain an acoustic wall meeting the requirements of class A4. It is important to choose the areas to cover well.
• an acoustic wall of class A2 is obtained while according to embodiments a, b, d and e an acoustic wall of class A3, respectively A4 is obtained.
• the surprising results of the acoustic walls comprising panels with a thickness of 75 mm make it possible to envisage the use of panels with a standard thickness of 50 mm, while fulfilling the requirements of class A4.
• FIG. 3 represents an acoustic wall with several acoustic absorbing panels in the shape of a “U” 20 each time covering a ridge 14 and the oblique parts 18, 18 ′.
• a panel 'U' 20 is molded to ⁇ match the profile of the sheet pile 12 of curtain on which it is fixed.
• Each panel 20 is fixed to the sheet pile curtain 12 at the crest 14.
• the two adjacent oblique parts 18, 18 ′ of the panel are not fixed to the sheet pile curtain 12. There remains an air space forming a cavity absorption 22 between the sheet pile and the sound absorbing panel.
• a connecting piece 26 of sound absorbing material is fixed on two sound absorbing panels parallel to the hollow of the sheet pile, so as to connect the two panels and cover the hollow of the sheet pile, while forming between the hollow and the part connecting an absorption cavity.
• the connecting piece is shown in detail in Figure 5.
• the small base a is 90 mm and the angle ⁇ is 45 °.
• the large base b varies according to the thickness c of the connecting piece:
• Figure 4 shows how the same sound absorbing panel and the same connection piece can be used for several types of sheet piles produced by ProfilArbed SA: a) sheet piles type PU 6 to PU 32 b) sheet piles type AZ 13 c) sheet piles type AZ 18 , AZ 26, AZ 36 d) sheet piles type AZ 48
• the acoustic absorbent panels used in this example are mainly composed of wood fibers, so they are easily machinable with traditional carpentry equipment. In addition, they are very stable over time: they resist the rigors of the climate (freeze-thaw, rain, UV), pollution (industrial gases, exhaust gases) and are non-flammable (class M1).
• the treatment of the surface of the panels by means of various techniques such as screen printing and special paints makes it possible to develop a wide decorative range.
• the surface of the panels can be embellished by various machining in relief.
• the fixing of the sound absorbing panels on the sheet piles is easily done using known fixing means.
• We can p. ex. use nails suitable for fixing absorbent panels which are directly implanted through the acoustic absorbent panels without any preliminary preparation. They fix the absorbent panel to the sheet pile using a plastic washer.
• the panels are joined together using stirrups which are directly nailed to the sheet piles. They ensure the flatness of the assembly by avoiding differences in level between the various panels.
• FIG. 6 shows a crowning piece 28 with a notch of width d.
• the width of the notch depends on the type of sheet pile used and the thickness of the sound absorbing panels:

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• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Building Environments (AREA)
• Devices Affording Protection Of Roads Or Walls For Sound Insulation (AREA)

Applications Claiming Priority (5)

Publications (1)

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• 1999
  • 1999-11-30 EP EP99965415A patent/EP1135557A1/de not_active Withdrawn
  • 1999-11-30 WO PCT/EP1999/009283 patent/WO2000032876A1/fr not_active Application Discontinuation

Non-Patent Citations (1)

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