Description

The invention relates to a wall assembly for an engineering structure and also to an engineering structure for use near roads, waterways and railways and the like, which engineering structure is built up of one or more wall assemblies according to the invention.

The use of wall assemblies, whether or not combined into an engineering structure functioning as a sound-damping structure near roads, waterways and railways is known in a general sense and in embodiments thereof.

Existing sound-damping wall assembly structures have the drawback that, in addition to being of complex design, they are costly to install and maintain and, in order to realise adequate sound-damping functionality, must have a considerable depth dimension.

The object of the present invention is to provide a wall assembly as well as an engineering structure as described in the introduction which, in addition to being of simpler design, further exhibits additional sound-damping functionality, making it possible to further reduce the structural dimensions.

In order to achieve that object, the wall assembly is according to the invention characterised in that the wall assembly forms an upright structure having at least one elevation surface, against which a substrate provided with a large number of homogeneously distributed projecting synthetic fibres is arranged. The large number of projecting synthetic fibres provides additional sound-damping functionality. As a result, the sound wall can be designed to have a smaller structural dimension whilst complying with the legal sound damping requirements. It has been found that it is possible to realise the same sound-damping functionality by using a smaller structural dimension in combination with a substrate provided with a large number of projecting synthetic fibres.

In another embodiment, the upright structure is an open structure, which is filled with a sound-damping mass. Said mass may consist of a fibre material, such as rock wool. In another embodiment, the upright structure is made of a stone-like material, for example a concrete type. In another embodiment, the upright structure is made up of a mesh panel, to which the acoustic transparent substrate provided with the large number of homogeneously distributed projecting synthetic fibres has been attached and which has additionally been provided with a sound-damping mass.

In a functional embodiment of the invention, the wall assembly, and in particular the upright structure, is built up of several posts placed some distance apart, between which one or more wall parts forming the elevation surface can be accommodated. The wall parts form a sound-damping mass, which imparts a first sound-damping functionality to the structure. Such a structure can be realised in a simple and inexpensive manner, whilst it can furthermore be readily used as a sound damping structure. The posts give the wall assembly thus realised a robust stability, so that it is quite resistant against wind influences. Furthermore, in case of damage (caused by vandalism or a traffic accident), the damaged wall parts and/or posts can be simply replaced rather than having to replace the entire wall assembly structure.

Additional functionality of the wall assembly according to the invention is obtained in that the wall part is provided with stretching means along at least part of its circumferential edge for stretching at least part of a circumferential edge of the substrate. Said stretching means comprise a first section and a second section, which second section can be accommodated in the first section. For stretching the substrate provided with the projecting synthetic fibres, the second section is provided with projections which engage in the circumferential edge of the substrate, and clamping means are provided for clamping the first and the second section in place relative to each other.

This ensures that the circumferential edge of the substrate will be properly retained between the two sections, in particular for longer periods of time. In addition, such engagement prevents the circumferential edge from becoming locally detached or damaged, since it is now clamped in place along a large circumferential length.

Stretching the substrate in the wall part along the major part of its circumferential edge on the one hand contributes toward obtaining an improved sound-damping surface and on the other hand ensures that the clamping engagement will be retained in a sufficiently stable manner in particular in the case of wind loads. Furthermore, the clamping engagement of the substrate can thus be ensured for a prolonged period of time. In a functional embodiment, the posts are H-section posts, which makes it possible to use a simple construction and to retain the wall parts in a stable manner. To ensure that the wall parts are properly retained between two adjacent H- sections, each wall part has a circumferential edge which, upon placement, will slip over de H-profile of the post. Thus, a functional and aesthetic abutment of two adjacent wall parts against each other can be realised, in which the post is fully covered by the two wall parts.

In another functional embodiment, the synthetic fibres have been tufted into the substrate. In another embodiment, the synthetic fibres have been woven into the substrate, making it possible to obtain a pile stability which makes it difficult to simply pull synthetic fibres out of the substrate.

In yet another embodiment, the substrate is an open fabric or a nonwoven.

As regards the synthetic fibres it can be noted that they can be configured as composite synthetic fibres, being a bundle of several types of synthetic fibres. In one embodiment, on the other hand, the synthetic fibres may be monofilament fibres, in which the shape, the thickness, the dimension and the material selection determine the additional sound-damping functionality of the synthetic fibres in the wall assembly.

According to the invention, in order to enhance the sound-damping functionality of the substrate provided with the large number of synthetic fibres, the synthetic fibres may be made up of different types of synthetic fibres. Thus, synthetic fibres exhibiting different functionalities, such as stiffness or sound damping, for example, can be incorporated in the substrate.

The invention will now be explained in more detail with reference to a drawing, in which:

Figures 1 a-1 c show three embodiments of a wall assembly according to the invention;

Figures 2a-2c show detail views of figure 1 ;

Figures 3a-3b are detail views of wall assemblies according to the invention;

Figures 4a-4d are detail views of the tightening means used in a wall assembly according to the invention; Figure 5 shows a substrate with synthetic fibres provided thereon for use in a wall assembly according to the invention.

For a better understanding of the invention, like parts shown in the various figures will be indicated by identical reference numerals in the description of the figures below.

The wall assemblies 10-10'-10", which function as noise reducing barriers, are made up of several posts 1 1a-1 1 b, which are placed some distance apart in the ground 1. As shown in figure 2a, each post has a foundation base 1 1 a1 - 11 b1 , which ensures a stable construction of the wall assembly, in particular for withstanding wind loads caused by the weather conditions or by the traffic driving past. The posts 11 a-11 b can be simply placed in the ground 1 with their foundation bases 11 a1 -1 1 b1 , obviating the need to use a complex and time-consuming driving technique. Each wall assembly 10-10'-10" has a first elevation surface 12a and, on the opposite side, a second elevation surface 12b.

According to the invention, at least one wall panel 20a-20b-20c-20d provided with a sound-damping mass can be mounted between each pair of adjacent posts 1 1 a-1 1 b, which mass has a primary sound-damping function.

In the embodiment shown in figure 1 a, the wall assembly 10 comprises four wall panels 20a-20d, whilst in the embodiment shown in figures 1 b and 1c two wall panels 20a-20b disposed one above the other are mounted between the posts 11 a and 1 1 b in the wall assemblies 10' and 10", respectively.

The two posts 11 a-11 b disposed beside each other can be interconnected near their upper side by means of a lintel 13, which also retains the wall panels 20a-20b. In addition to realising an aesthetic finish, the overall structure is thus given constructional stability. In addition, the lintel 13 provides protection, for example against weather influences, for the wall panels 20-20a-20b mounted between the posts 1 1 a-1 1b.

Each wall panel 20a-20b has a primary sound-damping function; in a first embodiment thereof it may be made of a stone-like material, such as concrete, functioning as a sound-damping mass. This embodiment is disclosed in figure 2c, in which regard it is noted that in this embodiment one wall panel 20 is mounted between the posts 1 1 a-11 b. In another embodiment, the wall panel 20-20a-20d may be configured as a mesh panel, between which a sound-damping mass, such as rock wall, is provided.

According to the invention, in order to realise additional sound- damping functionality, the wall assembly is provided with a substrate, on which a large number of homogeneously distributed projecting synthetic fibres are provided. An example of such a substrate is shown in detail in figure 5, in which the substrate is indicated at 30, with synthetic fibres of 32 provided thereon. The substrate is fixed to the elevation surface 12a (in this case the wall panel 20-20a-20b), using a fixing technique yet to be discussed hereinafter.

Such a substrate provided with the synthetic fibres 32 is partially shown by way of illustration in the embodiment shown in figure 2c and also in the detail view of figure 3a.

It will be understood that according to the invention the wall assembly 10-10'-10" may be provided with a substrate 30 provided with projecting synthetic fibres 32 on both elevation surfaces 12a-12b.

The substrate 30 is preferably acoustically transparent and may have an open structure and be made up of a fabric or a nonwoven, for example. In the embodiment shown in figure 5, the substrate 30 is made up of a fabric or a grid of support threads 31a-31 b, on which the synthetic fibres 32 are provided.

Various methods can be used for attaching the synthetic fibres 32 to the substrate 30. In a first application, the synthetic fibres 32 can be provided in the substrate 30 by means of a tufting technique, whilst another method of attaching the synthetic fibres comprises weaving the fibres into the substrate 30.

In particular weaving the synthetic fibres 32 into the substrate 30 provides an elevated pile stability, as a result of which the risk of the fibres 32 undesirably becoming detached from the substrate (due to vandalism, traffic accidents or weather influences) is significantly reduced.

The synthetic fibres may preferably be made of a polypropylene or polyethylene, but other synthetic materials may also be used.

In the embodiment shown in figure 5, the synthetic fibres 32 are worked into the substrate 30 as one fibre type, viz. monofilaments. It has been found that the sound-damping functionality of the substrate 30 with the synthetic fibres 32 provided thereon can be enhanced by working several types of synthetic fibres into the substrate 30. In this connection monofilament fibres combined with fibrillated or non-fibrillated, so-called tape of ribbon fibres may be considered.

Such different types of synthetic fibres may be provided in the substrate as separate fibres, but also in combination with each other as a composite fibre, which may in that case be made up of a bundle of several monofilament fibres held together by one or more (fibrillated) ribbon fibres.

Other types of synthetic fibres, including teased fibres, may also be worked into the substrate 30.

In this way it is possible to realise an open fibre structure - depending on the pile density of the synthetic fibres worked into the substrate - which, in addition to the primary sound-damping function of the wall part, has an additional sound-damping function. In particular the use of a substrate with several types of synthetic fibres provided thereon leads to an adequate absorption of sound in the high- and medium-frequency ranges and prevents said sound from being transmitted to the area therebehind.

In order to prevent damage to the substrate and the synthetic fibres due to vandalism or traffic accidents, so-called reinforcement threads 33 may be worked into the substrate 30, which reinforcement threads may in particular be glass fibres. Glass fibres impart additional reinforcement to the substrate 30 and, in the case of a fabric, can be provided between the support threads 31 a-31b during the fabric production process of the substrate 30. Such reinforcement glass fibres provide additional functionality as regards vandalism, for example, since said glass fibres 33 cannot easily be cut through by means of a knife, thus making it impossible to remove parts of the substrate 30 with synthetic fibres from the wall assembly 10- 10'-10".

As shown in figures 1c and 2a, retaining sections 14 may be used as additional protection against vandalism, which sections are installed over the substrate 30 and the synthetic fibres 32 and which are on the other hand mounted in the wall assembly. This, too, makes it more difficult for vandals to damage and remove the substrate 30 provided with the synthetic fibres 32.

Figures 3a-3b and 4 show an embodiment of fixing means for fixing the substrate 30 provided with the synthetic fibres 32 to the wall panel 20. In figures 3a-3b and 4, said means are indicated at 40-40', they function to stretch at least part of a circumferential edge 30a clampingly over the surface of the wall panel 20-20a- 20b-20c-20d.

It is noted that reference numeral 22 indicates a sound-damping mass, which may be a layer of rock wool, for example. The sound-damping mass or material layer 22 is provided between two elevation panels 21a-21 b on both elevation surfaces. In the embodiment shown in figure 3a, the wall panel 20 is mounted in the H-section post 1 1a. In the embodiment shown in figure 3b, the wall panel 20 is arranged over the flange 1 11a of the post 11 a, in abutment with the adjacent wall panel 20'.

The post 1 1 a is thus fully hidden from view by the two adjacent wall panels, which enhances the aesthetic appearance of the engineering structure beside roads etc.

The substrate 30 is placed into abutment with the elevation panel 21a, and the circumferential edge 30a is stretched, using the stretching means 40, so that the substrate 30 provided with the synthetic fibres 32 is stretched taut over the entire surface of the wall panel 20. The latter is desirable in order to prevent the substrate 30 becoming detached under the influence of, for example, wind loads. As already explained before, the retaining sections 14 additionally retain the substrate 30 against the wall panel 20.

The stretching means 40-40' are made up of two sections, which extend along the circumferential edge of the wall panel 20. Reference numeral 41 denotes a first stretching section, whilst reference numeral 42 denotes a second stretching section, which can be accommodated in the first stretching section 41. The second stretching section 42 is provided with projections 43, which engage in the circumferential edge 30a of the substrate 30. In the present case, the projections 43 extend through the substrate 30, as a result of which a significantly improved engagement between the switching means and the substrate 30 is achieved. Furthermore, undesirable detachment of the substrate due to vandalism, traffic accidents and/or wind loads is prevented as well as possible.

In another embodiment, the first stretching section 41 is provided with projections 43.

To stretch the substrate 30 over the wall panel 20, the second stretching section 42 must be received in the first stretching section 41. Both the first and the second stretching section are to that end provided with a flanged edge 41 b- 42b, the flanged edge 42b of the second stretching section being accommodable in the flanged edge 41 b of the first stretching section 41. Furthermore, the two stretching sections 41 -42 are provided with a bent end edge 41 a-42a, which additionally engage the two sides of the substrate 30 (see figures 4a-4d), thus realising an additional clamping action.

Both the first stretching section 41 and the second stretching section 42 are provided with clamping means for stretching the substrate 30, which clamping means are also made up of mating protrusions 41 c-42c, which are each provided with a coinciding bore provided with an internal screw thread, into which a screw 44 can be screwed. As a result, a correct and reproducible alignment of the two sections is realised, ensuring a prolonged and reliable stretching result of the substrate.

Upon tightening of the screw 44, the second stretching section is tightened over the protrusions until it fully abuts in the first stretching section 41. Upon tightening of the screw 44 and clamping down the first stretching section 42 in the second stretching section 41 , the circumferential edge 30a of the substrate 30 is carried along by the projections 43 engaging thereon and clamped between the end edges 41 a-42a of the two stretching sections 41-42. Accordingly, the substrate 30 is stretched taut over the surface 21 a of the wall panel 20.

Because similar stretching sections may be provided along each circumferential side of the wall panel 20, the substrate 30 can be stretched and clamped down omnilaterally in a simple and reliable manner, with the risk of undesirable detachment of the substrate, for example due to wind loads, being prevented as much as possible. As an alternative embodiment it suffices to stretch the substrate 30 at least on its two opposite sides, so that the wall panel 20 is only provided with the stretching means 40-40' on two sides.

As a contribution to road safety, the substrate 30 and/or the synthetic fibres 32 provided thereon may be provided with a flame-resistant or flame- retarding additive, which significantly reduces the risk of fire along motorways or near tunnels.

Likewise, the substrate 30 and/or the synthetic fibres 32 provided thereon may be provided with an additive that it more difficult for graffiti from vandals to adhere thereto, so that the graffiti can be readily removed, for example using water under high pressure. The substrate 30 is preferably acoustically transparent; in the illustrated embodiments it is configured as a flexible fabric or a non-woven, which may or may not be an open. In other embodiments, the substrate 30 may be less flexible or even be inherently stiff and be configured as a plastic or metal plate or as a metal gauze, for example.