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Title:
MUNICIPAL NOISE ABSORBING SCREEN
Document Type and Number:
WIPO Patent Application WO/2018/024263
Kind Code:
A1
Abstract:
The municipal noise absorbing screen consists of mutually interconnected panels. Each panel (7) is made of a reinforcing firm frame (15) filled with a core (18). This panel (7) is equipped with an outer noise absorbing layer made of bonded rubber granulate having a bulk density 650 to 750 kg.m"3 and a system of open and closed pores and containing 3 to 8 wt.-% of binder and 92 to 97 wt.-% of the said rubber granulate having the following fractional structure: up to 5 wt.-% of the up to 2 mm, 10 to 30 wt.-% of the 2 to 4 mm, up to 20 wt.-% of the 4 to 6.3 mm, 25 to 70 wt.-% of the 6.3 to 8 mm, and up to 30 wt- % of the 8 to 11.2 mm fractures. On the side facing the track (1), the panel (7) is provided with a relief pattern raising above the plane of the panel surface and with a top noise absorbing ridge (2).

Inventors:
LIDMILA, Martin (K Dubu 1714, Beroun, 266 01, CZ)
BRET, Ondřej (Družstevni ochoz 961/54, Prague 4, 140 00, CZ)
ŠAFNER, Karel (Lesni 263, Březová, 356 01, CZ)
Application Number:
CZ2017/000049
Publication Date:
February 08, 2018
Filing Date:
July 27, 2017
Export Citation:
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Assignee:
CZECH TECHNICAL UNIVERSITY IN PRAGUE (Faculty of Civil Engineering, Thákurova 7, Prague 6, 166 29, CZ)
International Classes:
E01F8/00; E01B19/00; E04B1/86
Foreign References:
CZ27589U12014-12-29
DE102008060102A12010-06-02
CZ29447U12016-05-25
Attorney, Agent or Firm:
BOBKOVÁ, Lenka (Czech Technical University in Prague, Rector's Office Patent Cente, Zikova 4 Prague 6, 166 36, CZ)
Download PDF:
Claims:
P A T E N T C L A I M S

1. Urban noise barrier comprised of mutually interconnected panels, characterized in particular by the fact that every panel (7) is formed of a firm reinforcing frame (15), filled core (18) consisting of a filler on which the outer noise-reducing layer is arranged, made of bonded rubber granulate with a density of 650 to 750 kg.nr3, With a system of open and closed pores, containing 3 to 8 % binder by mass and 92 to 97 % rubber granulate by mass in the following composition of individual fractions: 5 % fractions by mass to 2 mm, 10 to 30 % fractions by mass 2 to 4 mm, to 20 % fractions by mass 4 to 6.3 mm, 25 to 70 % fractions by mass 6.3 to 8 mm, to 30 % fractions 8 to 1 1.2 mm by mass, whereas a panel (7), on the noise absorbing side (1) facing the track is provided with a pattern rising above the surface and a ridge (2) with an acoustically absorbing function in the upper part and side walls have vertically protruding edges to secure the protruding ridges (3) of neighboring panels (7).

2. Urban noise barrier according to claim 1 , characterized in particular by the fact that every panel (7) is fitted from above with a groove (4) for placement of connecting elements (14).

3. Urban noise barrier according to claim 1 or 2, characterized in particular by the fact that the ratio of height of the panel (7) to the overall width of the panel (7) is 1 :1 to 2:1.

4. Urban noise barrier according any of the claims 1 to 3, characterized in particular by the fact that core (18) is made of recycled rubber.

5. Urban noise barrier according to claim 4, characterized in particular by the fact that the core has a bulk density of at most 300 kg/m3.

6. Urban noise barrier according any of the claims 1 to 3, characterized in particular by the fact that the core (18) is made of waste materials with a bulk density of under 300 kg/m3 selected from the group comprising polystyrene, mineral wool, textiles, and plastics.

7. Urban noise barrier according to claim 1 to 6, characterized in particular by the fact that the height of the panel (7) ranges from 250 to 500 mm.

8. Urban noise barrier according to claim 2 to 7, characterized in particular by the fact that the panels (7) are mutually connected by lath (14), placed into the groove (4) and attached by screws (17) to the reinforced frame (15).

9. Urban noise barrier according to claim 2 to 8, characterized in particular by the fact that the reinforced frame (15) is made of material selected from the wood and plastics group.

10. Urban noise barrier according to claim 2 to 9, characterized in particular by the fact that the binder is high molecular weight polyurethane.

Description:
MUNICIPAL NOISE ABSORBING SCREEN

Technical Field

The invention involves building elements for decreasing rail line noise arising from the contact of wheels on tracks near tram lines in developed and urban areas.

Technical Background

Currently, many variants of construction or other technical measures to reduce noise from transport, including rail, are known. Generally, these measures can be divided into active measures that prevent noise or minimize noise and passive measures to prevent the spread of existing noise.

As noise-reduction requirements concerning the maximum admissible noise level in developed areas increase, the long-term efforts to address noise from the city rail transport have also been increasing. Among the active measures from a construction point of view, a high-quality and well-maintained track is especially important, especially the choice and design of tracks, rail fastenings, application of rail absorbers, elimination of warping, and further, other non-construction measures classified as active can be implemented on the cars themselves. This includes maintenance of the wheel profile, and enclosure and other modifications of the chassis. Even with the application of a suitable combination of active measures, these eventually reach the limit of their possibilities and passive measures are needed to further reduce noise. Passive measures include, for example, classical anti-noise walls, applied not only to rail transport, but also to road transport. Recently, efforts have been made to develop elements of smaller size located closer to the source of noise in the form of various low-rise noise barriers

Noise walls, also referred to as noise barriers or screens, are built on noisy roads, motorways, railways or tramways to reduce the harmful effects of traffic noise. They should be built so as to integrate as seamlessly as possible into the surrounding countryside. They are located outside the pedestrian and transit areas. They are placed at a safe distance from the road, which depends on the vehicle impact resistance and the material deformation depth. Barriers longer than 300 meters must be provided with escape openings that are not more than 150 meters apart. In addition to the barriers, earth banks or slopes can also be used for sound insulation, which, for efficiency gains, can be planted with vegetation, which also protects them against erosion.

Examples of classic noise barriers are listed in documents CZ 2002-3686 A3, CZ 13 566 U1 , and CZ 27486 U1. Document CZ 2002-3686 A3 describes a noise barrier comprised of two vertical load-bearing elements, steel pillars - panels in the I shape, on which two load-bearing arms are mounted - L panels. This creates a steel frame in the shape of a block, which is further filled with noise-absorbing material, mineral wool and a single layer support plate. The total thickness of the wall is determined by the dimensions of the I-shaped steel panels used. In the patent filing, it is not clearly stated whether the noise barrier - panel is mounted on site or during production. The utility model, CZ 13 566 U1 , describes a concrete, prefabricated panel comprising a supporting part and a sound-absorbing layer, which consists of porous concrete with specific characteristics on the basis of siliceous sand, cement and a plasticizer. The concrete panels must be fitted between the vertical, supporting elements - posts. The utility model CZ 27486 U1 describes a reinforced concrete noise barrier made of a single panel of porous concrete of a special composition. The panel surface turned towards the source of the noise is formed by a trapezoidal wave of any shape.

Low-rise noise barriers are elements or building elements placed along a tram line, railway or other railroad track, whose application reduces the undesirable effects of noise generated during the passing of rail traffic. Low-rise noise barriers are positioned as close as possible to the passable cross panels, as defined by the technical valid standard. Their dimensions allow them to be located much closer to the noise source than conventional noise barriers, thereby reducing the dominant noise generated by the rail (rolling noise) and chassis noise. Depending on the material from which they are made, they may have absorptive or reflective properties.

Design s for low-rise noise barriers available up until now can be found, for example, in the CZ 21803 or CZ 23316 utility models. The components are usually made of concrete or similar solid materials, and mechanization is required during construction and handling, since the individual parts reach the weight of hundreds of kilograms. In order to ensure the stability of these elements, it is characteristic that they are based on their other dimensions in a relatively large width, which leads to the front of the base part coming close to the track construction - for example to the railroad tie. The material modification of the design from a series of low-level noise barriers is represented, for example, by the utility model CZ 29447, which enables vegetation cover from the exterior side as well as water retention, suitable for improving the climate in developed urban areas.

Noise barrier panels with a load-bearing structure made of concrete or another dense material present a high safety risk at the moment of changing their position in a direction intersecting the traffic cross-panels. The impact of a rail vehicle with a concrete element or other similar high-density element results in a significant threat to the safety of rail transport. The consequences of a possible collision are accompanied by significant financial consequences to vehicles, and, in extreme cases, to passengers' lives.

Another major problem of the state of the art is the possible intervention of units of the integrated rescue system for which concrete elements, metal elements or other elements with similar properties in this respect represent a significant obstacle for rapid and effective intervention, because the elements cannot simply be dismantled, or displaced without the use of heavy machinery and their destruction (for example, by cutting an opening in them) is also very problematic due to their massive, solid construction. For example, dismantling a common concrete noise barrier takes several hours and requires a crane. Saving lives, where every minute counts, is then significantly complicated. The efforts of fire brigades to cut through a barrier using a motorized grinder were unsuccessful, ending in the destruction of the grinder disks. Attempts at cutting using an electrode while burning oxygen also failed. In practice, concrete walls have not worked. A noise-blocking panel with an emergency exit safety element, as shown in document CZ 28784 U1, only partially resolves the problem.

Reinforced concrete walls also have drawbacks with respect to rapid wear and tear. For all anti-noise walls, including low noise barriers, it is characteristic that the side facing the noise source (to the track) is preferably made of an acoustically absorptive material. This means, as a rule, that noise barriers are generally multilayered, which, however, though it has a beneficial effect on noise attenuation, increases the difficulty and complexity of production, and the contact points of the various materials can be a source of various defects, arising, for example, from the movement of moisture and its condensation along the contact area of the layers. The noise- blocking elements also have, if possible, a curved shape towards the source of noise, either rounded or angled wall shapes, which increases the acoustic effect of these elements. It is also typical of the state of the art that the material constituting the acoustically absorbing layer facing the noise source does not simultaneously form the supporting part of the elements. Visually, therefore, the interfaces of multiple materials arise on the walls and barriers, which can, as mentioned above, become a source failures and shortened lifetime of the elements.

However, the abovementioned and other, similar, previous designs of low-rise noise barriers generally do not allow the placement of the face of the upper part of the noise barrier beyond the level of its foundation in the lower part, and the positioning of the elements on the track is close to or all the way below the ties, making it more difficult for some elements and impossible for others to be placed on existing lines without significant structural interventions, so it is possible to apply them only in case of new construction or reconstruction of lines.

The aim of the invention is to resolve insufficiencies in the current state of technologies. In particular, this means the possibility of installing an element without major construction interventions, even on existing tracks, whose technical condition does not require reconstruction or that have undergone reconstruction already, but despite this require further noise reduction, and to create an element that, if needed, will be relatively easy to overcome by dismantling or destruction, thereby enabling problem-free access for rescue units. Additionally, the aim is to create an element without the risk of malfunctions on the interface between the supporting and acoustically appropriate material and to create a visually unified element, without transitions in materials which, with its simplicity, will not markedly disrupt the architectural or aesthetic character of the places where it will be installed.

Essence of the invention

The essence of the invention is an urban noise barrier consisting of mutually interconnecting panels, whereas each panels is made of a sturdy, reinforced frame filled with a core of filler and on which an exterior acoustic absorption layer made of bonded rubber granulate is arrayed, with a density of 650 to 750 kg.rrr 3 , with a system of open and closed pores containing 3 to 8% binder and 92 to 97% by weight of a rubber granulate having the following composition of the individual fractions: to 5% fractions in sizes to 2 mm, 10 to 30% by weight of fractions of 2 to 4 mm, to 20% by weight of fractions of 4 to 6.3 mm, 25 to 70% by weight of fractions of 6.3 to 8 mm and to 30% by weight of fractions of 8 to 11.2 mm, whereas the panels with the side facing the track is provided with a pattern protruding above the plane of the surface and a relief with an acoustically absorbing function in the upper part, and the side walls have vertical protruding edges for securing to the edges of adjacent panels. The parts thus have an overlap and form a compact noise barrier together.

The material of the outer acoustically absorbing layer of bonded rubber granulate, is well resistant to weathering such as rain, frost, UV radiation, and heat. The stated material, in combination with the construction of the urban noise barrier pursuant to the invention specifications, is characterized by the fact that in the event of an emergency or accidents leading to the impact of a rail or road vehicle with a city noise barrier, the material damage to vehicles, as well as to infrastructure and even human life is minimized.

In the event of necessary intervention by Integrated Rescue System units or the need to use the rescue equipment for the derailed vehicle, the urban noise barrier, due to its overall design and construction, can be simply dismantled or, rapidly destroyed with conventional emergency equipment.

In a preferred execution, each panel is provided with a groove for locating the connecting element. In the event the extremely easy dismantling of the city noise barrier is required for safety reasons, it is most advantageous to connect the panels with a lath, placed in the groove and attach to the reinforcement with screws. Such a solution, for example, allows the barrier to be dismantled using basic equipment in just a few minutes.

Preferably, the ratio of the height of the panel to its total width is from 1:1 to 2:1. A ratio approaching 2:1 is characteristic for a city noise barrier located in an open rail bed, and a ratio approaching 1 :1 is typical when placed in the track structure with a covering. In one preferred design, the core of the panel is made of recycled rubber material, and even more preferably, this core has a bulk density of not more than 300 kg / m3.

In another preferred design, the core is made of waste material with a bulk density of to 300 kg / m3 selected from the group consisting of polystyrene, mineral wool, textiles, and plastic.

A lightened core, which makes up to 20 % of the volume of the panel, helps decrease the specific density of the panel to a mere 500 kg/m 3 .

The ideal height of the urban noise barrier panel is from 250 to 500 mm. At this height, it is easy to cross the barrier when necessary, for example when an accident occurs. Additionally, the panels at this height have a weight of 50 to 80 kg and can be handled without mechanization. This is advantageous both for the implementation of the noise barrier and for the necessity to quickly dismantle the wall in the event of an accident.

However, in some special cases, it may be necessary to produce longer noise barrier panels, according to the invention. This is possible, but their assembly would then require mechanization.

A pattern embossed above the plane of the surface can be executed not only from a functional point of view, but for aesthetic reasons, as the formability of the bonded rubber granulate allows both good molding in a form and good adhesion of paint. Easy creation of reliefs, color patterns or combinations of them make it possible to meet the requirements of architectural design.

The urban noise barrier, executed according to the invention, is characterized by its small size, which can be extended if necessary, placement at the minimum possible distance from the track axis and by a suitable material solution, improving not only its acoustic properties but also the appearance. The city noise barrier can be implemented during the construction of a new building project or reconstruction of the track, and it can even be added to an existing track without significant interventions in its construction.

The advantage of the urban noise barrier according to the invention, unlike the known noise barriers, is that along its length and height on the inner absorbing side facing the noise source, it is made of only one type of material and there is therefore no sudden change to materials or surfaces with different acoustic properties.

The exterior part of the urban noise barrier fulfills the function of acoustic absorption and its protective layer and is made of a bonded rubber granulate, which mainly comes from recycling lines for discarded tires and similar rubber waste. The bonded rubber granulate ensures good acoustic absorption of the surface of the city noise barrier and at the same time provides resistance to weathering and mechanical influences.

Appropriate granularity ensures the formation of a porous material structure, whereas the open pores help dampen noise.

The visible part is made of a single material, recycled rubber, which is simultaneously the load-bearing material and also creates the acoustically absorbing layer. This eliminates the risk of defects arising on the interface of the load-bearing and sound absorbing materials.

For its installation, the urban noise barrier does not require wet processes, nor permanently built in vertical elements such as posts, etc.

Overview of illustrations on drawings

The invention is clarified using drawings and illustrations, of which Fig. 1 and Fig. 2 express the axonometric views of a panels of the urban noise barrier; Figs. 3a, 3b, 4a, and 4b show selected possible methods of foundation; Figs. 5a, 5b, 5c, 5d show some possible variants of modification of the exterior, visible part of the panels; Fig. 6 shows a variant of the inner, absorbing surface, Fig. 7a shows an axonometric view of a panel in perspective showing the reinforcement, 7b and 7c are panels with views of the reinforcement. Examples of Execution of the Invention

Example 1

A specific execution of a panels, 7 of the urban noise barrier according to the invention is shown in Figs. 1 and 3a, axonometric overviews looking from the right and in Fig. 2, in an axonometric view looking from the left. The panels, 7, is formed of a plastic reinforcing frame 15, filled core 18 of mineral wool, only which the exterior noise absorbing layer of bonded rubber granulate is arrayed, in a composition of 8 % by mass binder and 92 % by mass rubber granulate with the following composition of individual fractions: 5 % fractions by mass under 2 mm, 25 % fractions by mass 2 to 4 mm, 10 % fractions 4 to 6.3 mm by mass and 60 % fractions by mass 6.3 to 8 mm. The inner, absorbing layer 1 facing the track is executed in the shape of a trapezoid, contributing to the dampening of noise. From the inner side 1, facing the track, there is a protrusion 2 in the upper part of the panel 7, adjacent to the traffic corridor cross- panels, or the outline of the vehicle, respectively. On the side of the panel 7 there is a ridge for securing the contact of two panels, 7, with overlap. The engagement 3_of the two adjacent panels 7 simultaneously together forms a groove for the foundation element 8. On the upper side of the panel 7_there is a groove 4, into which, after the installation of multiple adjacent panels 7, a connecting element 14, is inserted, securing mutual interconnection of the panels 7 and thereby also their synergy. The exterior, exposed side 5 facing away from the track, is smooth and can potentially be fitted with a colorful pattern, according to the wishes of the customer. Connection to the foundation elements, 8 is implemented in the lower section 6.

Example 2

Another execution of the urban noise barrier is shown on Fig. 3a axonometrically and on Fig. 3b in a cross-section of the constructions on a tram line with an open track bed, whose construction is shown by element 21_, the adjacent track 22 and the surface of the track bed 23. A panel 7 is made from a wooden reinforcing frame 15, filled core 18 of waste polystyrene, on which is arrayed the exterior noise absorbing layer made of bonded rubber granulate with a composition of 6 % by mass binder and 94 % rubber granulate by mass with the following composition of individual fractions: 30 % fractions by mass fractions 2 to 4 mm, 10 % by mass fractions 4 to 6.3 mm and 60 % by mass fractions 6.3 to 8 mm. The ridge 2 in the upper part of the panel 7Js beveled. Panel 7 placed on a prefabricated concrete base, and panels 8 laid in the track bed during construction of the track bed, or reconstruction of the track. A steel element 9 rises from the base panels 8^ of the same height as the panel 7. A steel element, 9, falls into place in the groove created by the adjoining sided walls of the panels 7 with a ridges (teeth) 3 ^ Further, two steel elements 10, protrude from the foundation panel 8 to increase the stability, and leading directly into the openings H in individual panels 7. Interconnection of the panels 7 is provided by a lath 14, placed in the groove 4. The lath 14 must have a length at least equal to the length of the panel 7, whereas a suitable length is double or triple of this length. The lath 14 must be placed so as to avoid contact being implemented at the point of contact on the panel 7, in which case mutual interconnection of neighboring panels 7 would not take place.

Example 3

Figs. 4a and 4b show the execution of the urban noise barrier in the variant of integration in the existing track, with grass cover, showing element 21 of the construction, the adjacent track 22, track bed surface 23, which can be covered by a separating cloth 24 to protect against soiling by earth particles, and a sod cover 25 placed on a layer of earth 26. A panel 7 is made of a wooden reinforcing frame 15, filled core 18 of bonded rubber granulate, on which the outer, acoustically absorptive layer is arranged. The core 18 and the exterior noise absorbing layer are made of bonded rubber granulate containing 3 % by mass polyurethane and 97 % by mass rubber granulate in the following composition: 10 % fractions 2 to 4 mm, 70 % fractions 4 to 6.3 a 20 % fractions 8 to 11.2. The ridge 2 is executed as perpendicular. This time, the panel, 7 s placed on a flat element 12 made of steel or hardened plastic, which is pushed into the ground 26 with a cover of vegetation. The principle is the same in the previous version, whereas the steel elements 9 and 10 have a shorter execution in respect of the lower height. The stability of the flat element 12 is provided by spikes 13 pushed into the ground 26 and covered by the track. The interconnection of the panels 7 is implemented using galvanized metal 19 of a length equal to the width of the panels, 7 and the length again at least equal to the length of the panels 7. The sheet metal sections 19 are screwed to the reinforcing frame 5 with screws V7_.

Example 4

Another possible design of the urban noise barrier is shown on illustrations 5a to 7c. These are panels similar the one in example 2. Fig. 5 shows examples of the possible variants of execution of the exterior, visible side 5. These examples may be implemented either in relief during the production of the elements or in color variations. This side has no effect on the acoustic properties of the urban noise barriers, and therefore it is possible to modify them as the customer wishes. For illustration, four possible designs are shown. Illustration 6 shows in an axonometric solution the inner, noise absorbing side 1 in the form of continuous pyramid shapes.

Figure 7a shows a specific, possible version of the reinforcing frame 15. In the axonometric view, the execution of the reinforcing frame 15, is clear, providing shape stability and the possibility of the joining of the parts 7 by means of a lath 14. In the cross-panels 7_ f Fig. 7b and the longitudinal panels of Fig. 7c, the interconnection of the lath, 14, with the reinforcing frame 15 using screws 17, is seen. The core 18 is lightened, leading to the significant lightening of the entire of the panel 7. In the longitudinal panels, the lath, 14, is evident, running across several adjacent panels 7, which results in the reinforcing of the city noise barrier.

Based on experimental measurements, it is possible to predict the reduction of noise from tram traffic resulting from the installation of an urban noise barrier executed according to the invention by approximately 4 dB, depending on the construction of the track, the makeup of the fleet, and other factors. Further optimizing of the shape and materials used can achieve a higher attenuation by additional decibel units.

It is necessary to emphasize that the stated examples of execution do not include all possibilities of specific designs of urban noise barriers. In the course of implementation of the invention, changes may arise, in particular, through modification of the visible part of the urban noise barrier, by, for example, changing the surface texture, rounding edges, modification of grooves, modification of anchoring elements and anchoring of panels to foundation elements, connecting of panels, etc.

Industrial Applicability

The urban noise barrier according to the invention can be used to dampen the noise from rail transportation everywhere a track is located on an independent body, mainly where other elements, either classical or even low-rise noise barriers, would disrupt the appearance or passability of the terrain, urban planning, or the nature of the location and its historical or landscape character.