GB2305451A

GB2305451A - Noise barrier sytem

Info

Publication number: GB2305451A
Application number: GB9618211A
Authority: GB
Inventors: Malcolm Stewart
Original assignee: KENNEDY LIONWELD Ltd
Current assignee: KENNEDY LIONWELD Ltd
Priority date: 1995-09-21
Filing date: 1996-08-30
Publication date: 1997-04-09
Anticipated expiration: 2016-08-30
Also published as: GB2305451B; GB9618211D0

Abstract

A noise barrier system comprises a series of posts and a plurality of panels 15 said panels 15 comprising a front side 16, a rear side 17, a top side 18, a bottom side 19 and two opposed ends 20, wherein the front side 16 is facing the source of the noise and wherein the panel comprises four distinct sections across its width, the first section 25, being the section exposed to the source of the noise comprises a relatively thin flat sheet material which comprises numerous perforations 26, the second section is a relatively thick gap of air 27, the third section is a relatively thick gap of noise absorption material 28 and the fourth section is a layer of relatively thin flat sheet material 29. An alternative noise barrier system (not shown) comprises a series of I beam shaped posts 11 which are spaced from each other and supported in the ground, each side of the I beam of the post 11 providing a U shaped channel 12 with side walls 13 extending outwardly and an inside surface 14, a plurality of noise reduction panels 15 are arranged between the two adjacent posts 11 and the opposing ends 20 of each panel 15 are inserted into the U shaped channels 12 of the two adjacent posts 11 to form a continuous barrier. The panels 15 are arranged parallel to the ground and in the case of the ground being inclined the opposing ends 20 of the panels are not parallel to the posts 11 but at an angle A which is the angle of inclination of the ground.

Description

A NOISE PROTECTION BARRIER SYSTEM The invention relates to a novel noise protection barrier system such as would be required as a barrier to sources of noise such as motor ways or rail tracks and protected areas such as residential areas and public areas.

Conventional noise pollution barriers comprise a layer of high density fibre insulation material as a noise absorbent and an outer layer or skin, usually of a corrosion resistant material such as aluminium which acts as a weather protector for the inner layer of noise absorbing material.

There have been significant increases in all forms of transport in recent years and increasing conflict in land use between public and residential areas and transport and industrial areas which generate noise. This increase in conflict has lead to an increased demand for improved performance in noise reduction barriers. It is also necessary to provide a noise barrier system which is pleasing to the eye and also which can be provided at an economically acceptable cost both in terms of the costs of manufacture and also the cost of erection on site.

It is therefore an object of the present invention to provide a noise barrier system which provides improved noise absorption characteristics compared to existing noise barrier designs and one which also withstands the effects of weathering and is aesthetically appealing and is also economic to manufacture and erect.

By means of the present invention there is provided a noise barrier system comprising a series of I beam shaped posts which are spaced from each other and supported in the ground and extending upwards, each side of the I beam of the post providing a U shaped channel with side walls extending outwardly and an inside surface, a plurality of noise reduction panels which are essentially elongate and parallelepided with a front and a rear side a top and bottom edge and two opposing ends and which are arranged between the two adjacent posts and the opposing ends of the panel being are inserted into the U shaped channels of the two adjacent posts to form a continuous barrier, characterised in that the panels are arranged parallel to the ground and in the case of the ground being inclined the opposing ends of the panels are not parallel to the posts but at an angle A which is the angle of inclination of the ground. This results in triangular shaped gaps between the ends of the panels and the inside surface of the U shaped channels of the I shaped posts.

In a preferred embodiment of the invention when the angle of inclination of the ground is relatively large the side walls of the U shaped channel may be made longer in order that the panel will still be supported inside the U shaped channel so that the side walls of the U shaped channel extends beyond the gap between the end of the panel and the inside surface of the U shaped channel.

In a further aspect of the invention the posts may be erected at an angle to the vertical in order to compensate for the angle of inclination of the ground.

Preferably the angle of inclination of the post to the vertical will be approximately half the angle of inclination of the ground. This enables the length of the side all of the U shaped channel of the post to be reduced.

According to a further aspect of the invention the posts are covered by means of a cover plate which is essentially a very shallow U shaped plate with a central cover part which extends over the width of the post and flange parts at each end which are attached to the panels by means of bolts or rivets.

According to a further aspect of the invention there is provided a noise reduction barrier system comprising a series of posts and a plurality of panels arranged between them, the said panels comprising a front side, a rear side, a top side, a bottom and two opposed ends, wherein the front side is facing the source of the noise and wherein the panel comprises four distinct sections across its width, the first section, being the section exposed to the source of the noise comprises a relatively thin flat sheet material which comprises numerous perforations, the second section is a relatively thick gap of air, the third section is a relatively thick gap of noise absorption material and the fourth section is a layer of relatively thin flat sheet material.

The first section is preferably made from a sheet metal material preferably corrosion resistant aluminium grade 1200 to British standard 1470 and perforated.

The perforations are preferably between 2.0 mm and 4.0 mm diameter at centres which are between 4.0 mm and 6.0 mm apart Preferably the total open area will be between 20 and 50 %.

The third section is preferably a high performance noise absorption material such as mineral wool having a minimum density of 60 kg per cubic metre. The fourth section is preferably made of the same material as the first section but without any perforations.

Preferably the first and fourth sections are relatively thin having a thickness of the order of 1 to 1.4 mm, whereas the second and third sections are relatively thick having thickness respectively of the order of between 30 and 60 mm and 55 and 90 mm. Preferably the second section or air gap will have a thickness of between one third and one half of that of the third section of noise absorption material.

Preferably the first and fourth sections of sheet material will include a profiled surface with indented sections along its length.

More detailed embodiments of the invention will now be described with reference to the accompanying drawings in which: Fig. 1 is a front elevation of a noise barrier system of the prior art; Fig. 2 is a front elevation of the noise barrier system according to the invention; Fig. 3 is the same as fig. 2 with a steeper ground incline; Fig. 4 is the same as fig. 2 with a reducing height barrier; Fig. 5 is an end view of the cover plate; Fig. 6 is a cross sectional view from above of the post and two panel ends; Fig. 7 is a vertical cross sectional view of the noise barrier system; Fig. 8 is a vertical cross section of the panel.

Referring to figure 1 a noise barrier system 1 of the prior art is shown extending up sloping ground. The system comprises posts 2 and panels 3. The panels are all laid horizontally so that they fit conveniently with the vertical posts in abutting perpendicular relationship. This is essential to the erection on site of existing noise barrier systems. This system has a number of disadvantages. Firstly the system is staggered in height between posts and does not provide an even barrier to the noise which can result in undesirable variations in the noise level.It also means that to achieve the minimum required noise level the height at the shortest part of the barrier will have to be at the minimum height which means that the higher parts of the barrier will both be an unnecessary use of materials for the barrier and also the excessive height may have a detrimental effect of the local environment.

A second major disadvantage of this type of barrier system is that the lowermost panels 4 have to be cut to size at the erection site. At some steep inclines it may be necessary to cut away parts from two panels for each section. This is both wasteful of the panels themselves which makes the manufactured cost of the barrier system high and is also very time consuming at the site of erection and also requires the use of sawing equipment at the erection site both of which add a great deal to the costs of erection of the barrier.

Additionally the stepped arrangement between the posts and the top most barriers can become corrosion sites.

Referring now to figures 2 to 8 and the barrier system according to the invention and particularly to figures 2 and 6 a noise barrier system 10 is shown comprising a series of I beam shaped posts 11 which are spaced from each other and supported in the ground to extend upwards. Each side of the I beam of the post 11 provides a U shaped channel 12 with side walls 13 extending outwardly and an inside surface 14. A plurality of noise reduction panels 15 which are essentially elongate and parallelepided. Referring also to figure 7 each panel is provided with a front side 16 and a rear side 17, a top edge 18 and a bottom edge 19 and two opposing ends 20 and which are arranged between the two adjacent posts 11 and the opposing ends 20 of each panel 15 are inserted into the U shaped channels 12 of the two adjacent posts 11 to form the continuous barrier 10.

The panels 15 are arranged parallel to the ground and in the case of the ground being inclined the opposing ends 20 of the panels are not parallel to the posts 11 but at an angle A which is the angle of inclination of the ground.

Referring to figure 3 the noise barrier system according to the invention is provided on ground which is inclined at a relatively steep angle, shown in figure 3 as 15 degrees. In such a case the side walls 13 of the U shaped channel 12 are of sufficient length that they extend to the ends of the panels 15 and beyond the gap formed by the angle of inclination of the panel 15 with respect to the post 11. In order to provide posts with such long extending side walls it may be necessary that the I beam post is formed by two U shaped beams secured back to back by a suitable means such as welding.

In order to minimise the length of the side walls it is possible, as shown in figure 3, to arrange that the posts 11 are erected at an angle to the vertical in order to compensate for the angle of inclination of the ground. Preferably the angle of inclination of the post to the vertical is approximately half the angle of inclination of the ground so that the extent of the length of the side walls 13 is minimised.

Referring to the figures it can also be seen that a continuous top rail 32 can be provided along the entire length of the barrier which provides protection against water and other corrosive causing substances along the entire length of the barrier.

Referring to figure 4 it can be seen that with the system of the present invention can be arranged to gradually reduce the height of the barrier for use at the end of the barrier to result in a gradual reduction in the barrier height in a way that is pleasing to the eye. This gradual height reduction is also useful for the interruption of the barrier at bridges.

As shown in figures 5 and 6 the posts 11 are covered by means of cover plates 21 which are essentially very shallow U shaped plates with a central cover part 22 which extends over the width of the post and flange parts 23 at each end which are attached to the panels by means of bolts or rivets 24. The cover plates can be arranged to be of the appropriate size for the length of the side walls 13 of the posts 11. The cover plates ensure that rain and other corrosion elements such as dust and debris from traffic fumes or the like are prevented from entering the gaps between the posts 11 and the panels 15 and forming corrosion sites. The cover plates also contribute significantly to the noise reduction effect of the barrier.The cover plates are secured to the panels by means of bolts or rivets and preferably neoprene, or fire retarding polyester seals 24, 24a are provided between the flanges parts 23 of the cover plate 21 and the panels 15 to provide an effective waterproof and noise abating seal. Alternatively or additionally the seals 24, 24a can be provided on the ends of the I beams 13 to fill the gap between the I beam 13 and the panel on one side and the cover plate 21 on the other.

Referring now to figures 7 and 8 the noise barrier system according to the invention comprises a plurality of panels 15 arranged between the posts 11. The panels 15 comprise a front side 16, a rear side 17 a top side 18, a bottom side 19 and two opposed ends 20. The front side 16 is facing the source of the noise and the panel comprises four distinct sections across its width. The first section 25, being the section exposed to the source of the noise comprises a relatively thin flat sheet material which comprises numerous perforations 26. The second section is a relatively thick gap of air 27, the third section is a relatively thick gap of noise absorption material 28 and the fourth section is a layer of relatively thin flat sheet material 29.

This second air gap section 27 provides weathering protection to the third section of noise absorption material.

The first section is preferably made from a sheet metal material such as corrosion resistant aluminium grade 12000 to British standard 1470 and is perforated.

The perforations are between 2.0 mm and 4.0 mm diameter at centres which are between 4.0 mm and 6.0 mm apart and in the present embodiment the perforations are 3.0 mm diameter at centres 5.0 mm apart.

The total combined area of all the perforations, otherwise known as the total open area is preferably between 20 and 50 %. In the embodiment shown the total open areais33%.

The third section is preferably a layer of a high performance noise absorption material such as mineral wool having a minimum density of 60 kg per cubic metre.

The fourth section is preferably made of the same material as the first section but without any perforations. For the preferred material aluminium sheet the thickness of the order of 1 to 1.4 mm, and in the embodiment shown the thickness is 1.2 mm. The second and third sections are however relatively thick having thickness respectively of the order of between 30 and 50 mm and 55 and 90 mm. In the embodiment shown these are 50 mm and 75 mm respectively. It has been determined by the inventor that the ratio of the air gap to the noise absorbing material is essential in providing the ideal performance. Ideally the second section or air gap has a thickness of between one third and one half of that of the third section of noise absorption material.

This has been surprisingly found since following conventional thinking an air gap behind an outside perforated layer would have been the least desirable feature due to unpredictable acoustic effects. Whereas the panel of the invention has a distance between the outer layer from the noise absorbing material to improve the weatherproofing effect of the outer layer. By means of the invention the inventor has achieved an optimum combination of weather proofing and noise absorption as well as providing a barrier system which can be erected with speed and is economic to erect and manufacture and which is very light in weight.

The first and fourth sections of sheet material matter also include a profiled surface with indented sections 30 along its length. This assists in stiffening of the outer layer and also improves the acoustic properties in combination with the other constructional features of the panel of the invention.

It will be appreciated that other embodiments of the above barrier system can be envisaged by the person skilled in the art which use the essential features of the present invention which is defined in the following claims.

Claims

1. A noise barrier system comprising a series of posts 11 and a plurality of panels 15 arranged between them said panels 15 comprising a front side 16, a rear side 17, a top side 18, a bottom side 19 and two opposed ends 20, wherein the front side 16 is facing the source of the noise and wherein the panel comprises four distinct sections across its width, the first section 25, being the section exposed to the source of the noise comprises a relatively thin flat sheet material which comprises numerous perforations 26, the second section is a relatively thick gap of air 27, the third section is a relatively thick gap of noise absorption material 28 and the fourth section is a layer of relatively thin flat sheet material 29.

2. A noise barrier system according to claim 1, characterised in that the first section is preferably made from a sheet metal material such as corrosion resistant aluminium grade 1200 to British standard 1470 and is perforated.

3. A noise barrier system according to claim 2, characterised in that the perforations are between 2.0 mm and 4.0 mm diameter at centres which are between 4.0 mm and 6.0 mm apart.

4. A noise barrier system according to claim 2, characterised in that the total open area is between 20 and 50 %.

5. A noise barrier system according to claim 1, characterised in that the third section is a high performance noise absorption material such as mineral wood having a minimum density of 60 kg per cubic metre.

6. A noise barrier system according to claim 1, characterised in that the fourth section is preferably made of the same material as the first section but without any perforations.

7. A noise barrier system according to claim 1, characterised in that the first and fourth sections are relatively thin having a thickness of the order of 1 to

1.4 mm, whereas the second and third sections are relatively thick having thickness respectively of the order of between 30 and 55 mm and 50 and 90 mm.

8. A noise barrier system according to claim 1, characterised in that the second section or air gap has a thickness of between one third and one half of that of the third section of noise absorption material.

9. A noise barrier system according to claim 1, characterised in that the first and fourth sections of sheet material include a profiled surface with indented sections along its length.

10. A noise barrier system 10 comprising a series of I beam shaped posts 11 which are spaced from each other and supported in the ground to extend upwards, each side of the I beam of the post 11 providing a U shaped channel 12 with side walls 13 extending outwardly and an inside surface 14 a a plurality of noise reduction panels 15 which are essentially elongate and parallelepided with a front side 16 and a rear side 17 a top edge 18 and a bottom edge 19 and two opposing ends 20 and which are arranged between the two adjacent posts 11 and the opposing ends 20 of each panel 15 are inserted into the U shaped channels 12 of the two adjacent posts 11 to form a continuous barrier, characterised in that the panels 15 are arranged parallel to the ground and in the case of the ground being inclined the opposing ends 20 of the panels are not parallel to the posts 11 but at an angle A which is the angle of inclination of the ground.

11. A noise barrier system according to claim 10, characterised in that the side walls 13 of the U shaped channel 12 extend to the ends of the panels 15 and beyond gap formed by the angle of inclination of the panel 15 with respect to the post 11.

12. A noise barrier system according to claim 10, characterised in that the I beam post is formed by two U shaped beams secured back to back by a suitable means such as welding.

13. A noise barrier system according to any one of the preceding claims, characterised in that at least one of the posts 11 is erected at an angle to the vertical in order to compensate for the angle of inclination of the ground.

14. A noise barrier system according to claim 13, characterised in that the angle of inclination of the post to the vertical is approximately half the angle of inclination of the ground.

15. A noise barrier system according to any one of the preceding claims, characterised in that the posts 11 are covered by means of at least one cover plate 21 which is essentially a very shallow U shaped plate with a central cover part 22 which extends over the width of the posts and flange parts 23 at each end which are attached to the panels by means of bolts or rivets 24.