Suspension-type sound reduction device and viaduct

Abstract

To reduce a vertical length of a suspension-type sound reduction device without lowering its sound reduction performance.SOLUTION: In a cylindrical suspension-type sound reduction device 10 forming a noise passage part 4 at a lower part of an opening part to a viaduct provided with the opening part on a floor surface, a plurality of projecting plates 5 forming slits 11 along a direction orthogonal to its longitudinal direction are projected from a cylindrical suspension-type sound reduction device main body 3 toward the noise passage part 4 at a part in the longitudinal direction of the noise passage part 4, and a sound absorbing material 6 is attached to an inner surface of the suspension-type sound reduction device main body 3 at a remaining part in the longitudinal direction of the noise passage part 4.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a cylindrical suspended sound reduction device and a viaduct. [Background technology]

[0002] Conventionally, for example, in railway viaducts in snowy regions, noise is emitted downward from openings provided to remove snow from the floor on which railway vehicles run, and in order to reduce this noise, it has been considered to provide a cylindrical suspended noise device that forms a noise passage below the opening (see, for example, Patent Document 1 and Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-12306 [Patent Document 2] Japanese Patent Publication No. 2020-204254 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned conventional patented invention, as shown in Figures 8 and 9, a sound-absorbing material is attached to the cylindrical suspended noise reduction device body, which is approximately 3 meters long in vertical length and is suspended from the underside of the viaduct. This makes it stand out in the landscape. Furthermore, the longer the vertical length, the greater the weight of the structure itself, and the greater the external forces exerted by wind pressure and seismic motion. This means that greater attachment strength is required for the underside of the viaduct, and there are also concerns that long structures may reduce the efficiency of construction work. Furthermore, these factors are expected to increase manufacturing and construction costs.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve the above problems and to make it possible to reduce the vertical length of a hanging type sound reduction device without reducing the sound reduction performance. [Means for solving the problem]

[0006] The characteristic configuration of the first hanging type sound-reduction device of the present invention is that it is a cylindrical hanging type sound-reduction device for an elevated bridge with an opening in the floor surface that forms a noise passage below the opening, and in which a plurality of protruding plates that form slits along a direction perpendicular to the longitudinal direction of a portion of the noise passage in the vertical longitudinal direction protrude from the cylindrical hanging type sound-reduction device main body towards the noise passage, and in the remaining vertical longitudinal portion of the noise passage in the vertical longitudinal direction, sound-absorbing material is attached to the inner surface of the hanging type sound-reduction device main body.

[0007] According to the first characteristic configuration of the present invention, as shown in Figures 5 and 6, a plurality of protruding plates that form slits along a direction perpendicular to the longitudinal direction of the noise passing portion are protruded from the cylindrical suspended type sound reduction device main body towards the noise passing portion in part of the vertical longitudinal direction of the noise passing portion, and sound absorbing material is attached to the inner surface of the suspended type sound reduction device main body in the remaining vertical longitudinal portion of the noise passing portion, thereby achieving a large sound reduction effect, particularly in the low to mid frequency range of noise associated with passing vehicles, etc., and as a result, it is possible to shorten the vertical length of the suspended equipment sound reduction device.

[0008] A second characteristic configuration of the present invention is that the viaduct is for railway vehicles with tracks formed on its deck, and the opening is a snow removal opening for allowing fallen snow to fall and be discharged from the tracks.

[0009] According to the second characteristic configuration of the present invention, in addition to being able to achieve the above-mentioned effects of the first characteristic configuration of the present invention, the sound reduction effect for low to mid-range sounds generated when vehicles run on railway tracks is greater, and as a result, while making it possible to remove snow from openings in the deck, the sound reduction effect from those openings can be achieved to the same extent or better than that of a typical viaduct without openings.

[0010] In a third characteristic configuration of the present invention, the plurality of protruding plates are provided with breathable slit protection films that cover the slits.

[0011] According to the third characteristic configuration of the present invention, by providing the protruding plate with a breathable slit protective film that covers the slit, it is possible to prevent snow from accumulating on the protruding plate when snow on the track is dropped through the opening, and to avoid impairing the sound reduction effect of the slit.

[0012] In a fourth characteristic configuration of the present invention, the slit protection film is made of a porous sintered aluminum material.

[0013] According to the fourth characteristic configuration of the present invention, the porous aluminum sintered material can adjust the sound reduction frequency by combining it with the air layer formed behind it, so that a sound reduction effect can be expected particularly in the mid-to-high frequency range, and it is also highly durable and can be used for a long period of time.

[0014] In a fifth characteristic configuration of the present invention, the plurality of protruding plates are installed with their tip ends inclined downward.

[0015] According to the fifth characteristic configuration of the present invention, snow falling from the opening is less likely to accumulate on the protruding plates whose tip ends are inclined downward, and the sound-reducing effect of the slits can be maintained at a high level.

[0016] The characteristic configuration of the sixth viaduct of the present invention is such that an opening is provided in the floor surface, and a cylindrical suspended sound-reduction device is provided below the opening to form a noise passageway, and the suspended sound-reduction device is constructed by having a plurality of protruding plates that form slits along a direction perpendicular to the longitudinal direction of a portion of the noise passageway in the vertical longitudinal direction protrude from the cylindrical suspended sound-reduction device main body towards the noise passageway, and sound-absorbing material is attached to the inner surface of the suspended sound-reduction device main body in the remaining vertical longitudinal portion of the noise passageway.

[0017] According to a sixth characteristic configuration of the present invention, a plurality of protruding plates that form slits along a direction perpendicular to the longitudinal direction of the noise passing section are protruded from the cylindrical suspended sound-reduction device main body towards the noise passing section in part of the vertical longitudinal direction of the noise passing section, and sound-absorbing material is attached to the inner surface of the suspended sound-reduction device main body in the remaining vertical longitudinal portion of the noise passing section, thereby achieving a large sound-reduction effect, particularly in the low to mid frequency range of noise associated with the passage of vehicles, etc., and as a result, it is possible to construct an elevated bridge in which the vertical length of the suspended equipment sound-reduction device can be shortened.

[0018] In a seventh characteristic configuration of the present invention, a track for a railway vehicle is formed on the floor surface, and the opening is a snow removal opening for allowing fallen snow to fall and be discharged from the track.

[0019] According to the seventh characteristic configuration of the present invention, the noise reduction effect for low to mid-range sounds generated when vehicles run on railway tracks is increased, and as a result, snow can be removed from openings while the noise from the openings can be reduced as effectively as or better than that of a typical viaduct without openings.

[0020] The eighth characteristic configuration of the present invention is to provide an upper and lower through-hole that forms an opening or gap between a plurality of parallel roads, and to provide a cylindrical hanging sound-reduction device that forms a noise passageway at the bottom of the upper and lower through-hole, the hanging sound-reduction device is constructed by providing a plurality of protruding plates that form slits along a direction perpendicular to the longitudinal direction of a portion of the noise passageway in the upper and lower longitudinal directions, which protrude from the cylindrical hanging sound-reduction device main body towards the noise passageway, and by attaching sound-absorbing material to the inner surface of the hanging sound-reduction device main body in the remaining upper and lower longitudinal parts of the noise passageway.

[0021] According to an eighth characteristic configuration of the present invention, a plurality of protruding plates that form slits along a direction perpendicular to the longitudinal direction of the noise passing section are protruded from the cylindrical suspended sound-reduction device main body towards the noise passing section in part of the vertical longitudinal direction of the noise passing section, and sound-absorbing material is attached to the inner surface of the suspended sound-reduction device main body in the remaining vertical longitudinal portion of the noise passing section, thereby achieving a large sound-reduction effect, particularly in the low to mid frequency range of noise associated with the passage of automobiles and the like, and as a result, it is possible to construct an elevated bridge in which the vertical length of the suspended equipment sound-reduction device can be shortened.

[0022] In a ninth characteristic configuration of the present invention, the road is at least one type selected from a general roadway, an expressway, a railway, a concrete guideway, a sidewalk, and a promenade.

[0023] According to the ninth characteristic configuration of the present invention, it is possible to achieve a sound reduction effect on noise emitted downward from the vertical penetration parts, which is equal to or greater than that of a typical viaduct without vertical penetration parts. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a graph comparing the sound reception levels of test specimen (a) and test specimen (b) with respect to comparative test specimen 1. [Figure 2] 10 is a graph showing the received sound levels of test specimens (c) and (d). [Figure 3] 10 is a graph showing the comparative sound receiving levels of comparative test specimens 1, 2, and 3. [Figure 4] 10 is a graph showing differences in the received sound levels of the first noise, the second noise, and the third noise relative to background noise. [Figure 5] FIG. 1 shows longitudinal cross-sectional views of test specimen (a) and test specimen (b). [Figure 6] 1A and 1B are longitudinal cross-sectional views of a hanging type sound reduction device of the present invention, in which (A) is a longitudinal side view and (B) is a longitudinal front view taken along line AA in (A). [Figure 7] 1A and 1B are longitudinal cross-sectional side views of test specimens with slits according to the present invention, in which (A) is a test specimen without a slit protection film and (B) is a test specimen with a slit protection film. [Figure 8] FIG. 1 is a longitudinal cross-sectional side view of comparative specimens 1, 2, and 3. [Figure 9] FIG. 2 is a longitudinal sectional side view of the model testing device. [Figure 10] FIG. 2 is a longitudinal cross-sectional side view of the viaduct of the model testing device. [Figure 11] FIG. [Figure 12] This is a longitudinal cross-sectional side view of an actual viaduct. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In regions with heavy snowfall, as shown in Figures 11 and 12, in viaducts 2 that form tracks for railway vehicles on a concrete deck 1, openings 7 are sometimes formed in the deck 1 as snow removal ports to allow fallen snow to fall off the tracks, and noise caused by passing vehicles is emitted below through these openings 7. Therefore, as shown in FIGS. 9 and 10, a hanging type sound reducing device 10 that forms a noise passing section 4 below the opening 7 is provided. As shown in Figure 6, the hanging sound reduction device 10 has a cylindrical metal hanging sound reduction device main body 3, and a plurality of protruding plates 5 that form slits 11 along a direction perpendicular to the longitudinal direction of a noise passing section 4 formed inside the hanging sound reduction device main body 3 are protruded from the hanging sound reduction device main body 3 towards the noise passing section 4 in part of the vertical longitudinal direction (the long side part in a plan view), and sound absorbing material 6 is attached to the inner surface of the hanging sound reduction device main body 3 in the remaining vertical longitudinal part of the noise passing section 4 (both the short side part and the long side part in a plan view).

[0026] The plurality of protruding plates 5 are installed with their tip ends inclined downward so that snow falling and being discharged from the openings 7 does not pile up on the protruding plates 5 when it falls, and in addition, a breathable slit protection film 8 is provided to cover the slits 11 between the plurality of protruding plates 5 in order to prevent snow from entering the slits 11.

[0027] The slit protection film 8 is made of a porous sintered aluminum material and exhibits a damping effect in the high frequency range.

[0028] [Test 1] Noise measurements were taken at evaluation point 9 (approximately 25 m from the center of the track and equivalent to a height of 1.2 m) on the viaduct shown in Figure 12, and the following noise levels were measured against the background noise when no vehicles were passing: No. 1 noise emitted when a vehicle passes on a typical closed-floor viaduct without the openings 7; No. 2 noise emitted when a vehicle passes on an open-floor viaduct with the openings 7; and No. 3 noise when a hanging sound-reducing device similar to the comparative test specimen 1, which is a metal tube approximately 3 m long with sound-absorbing material 6 attached to the inside, was installed below the openings 7. These noise levels were determined through simulation tests and are shown in the line graphs in Figure 4.

[0029] According to the graph in Figure 4, the third noise is almost equal to the first noise, and it can be seen that the installation of the hanging type sound reduction device 10 can reduce the adverse effect of the increase in noise caused by the installation of the snow removal opening 7.

[0030] The following model test was carried out on the hanging type sound reduction device 10 having a sound absorbing material 6 attached to the inner surface of a metal tube, as shown in Figs. In the figure, 9 is the evaluation point and 12 is the sound source that generates the noise.

[0031] [Test 2] That is, a conventional hanging sound-absorbing device with a vertical length of approximately 3 meters was scaled down, and as shown in Figure 8, the sound-absorbing portion was approximately 300 mm long and had sound-absorbing material 6 attached to the inside, and comparative test piece 1 was called "H300 sound absorption," and the sound-absorbing portion was approximately 250 mm long, and comparative test piece 2 was called "H250 sound absorption," and the sound-absorbing portion was approximately 200 mm long, and the sound-absorbing portion was called "H200 sound absorption," and the sound-absorbing effects were measured and shown in the line graph in Figure 3. This shows that the "H300 Sound Absorption" comparative test piece 1 has a greater sound reduction effect than the other test pieces.

[0032] [Test 3] Next, in comparison with the sound reception level (dB) of the "H300 sound absorption" of the comparative test specimen 1, the test specimens of the present invention shown in Figure 5 were prepared by installing a plurality of protruding plates 5, which had slits in a direction perpendicular to the longitudinal direction in part of the vertical length, protruding from the main body 3 of the hanging type sound reduction device towards the noise passing section 4, and installing sound absorbing material 6 on the inner surface of the main body 3 of the hanging type sound reduction device in the remaining part of the vertical length of the noise passing section 4, so that the part that actually has the sound absorption function is approximately 250 mm in total length, as test specimen (a) (Figure 5(A)) called "H250 slits + sound absorption", and the part that actually has the sound absorption function is 200 mm in total length, as test specimen (b) (Figure 5(B)) called "H200 slits + sound absorption", and the sound reception level (dB) of each is shown on the line graph in Figure 1. A slit protection film 8 made of a porous sintered aluminum material is attached over the plurality of protruding plates 5. As a result, it is clear that the sound receiving level (dB) of test specimen (a) and test specimen (b) is lower than that of comparative test specimen 1, and the overall length can be shortened.

[0033] [Test 4] As shown in Figure 7, the difference in sound reduction performance between test specimen (c) (Figure 7(A)), in which the part that actually has sound absorption function is only a slit with a total length of approximately 200 mm, and test specimen (d) (Figure 7(B)), in which the part that actually has sound absorption function is only a slit with a total length of approximately 200 mm and felt is attached as a slit protection film 8, was measured and shown in the graph of Figure 2. This shows that the sound reduction effect is greater in the high frequency range when the slits 11 are provided with felt than when the slits 11 are provided alone.

[0034] [Another embodiment] Other embodiments will be described below. <1> The slit protection film 8 may be made of a nonwoven fabric or other felt, other than sintered aluminum material, or may be made of a porous sound-absorbing material (polyester wool, glass wool, rock wool, etc.), a woven fabric such as glass cloth, or a fine-pored plate. Any breathable plate-like material (such as a punched metal with openings, a polycarbonate plate, etc.) that protects the above-mentioned materials may be used as long as it is a breathable covering material. <2> As long as the slit protection film 8 prevents snow falling through the noise passage section 4 from entering the slits 11, the protruding plates 5 do not have to be installed with their tips inclined downward. For example, they may be installed at a right angle to the noise passage direction or in the opposite direction. <3> The spacing between the adjacent protruding plates 5 and the protruding lengths of the protruding plates 5 do not all need to be uniform, and a plurality of combinations may be used in accordance with the target frequency. <4> In addition to the combination of the slits formed by the protruding plates and the sound-absorbing material, the inside of the hanging type sound-reduction device main body 3 may be provided with only slits. <5> In the specification of the present invention, the term "road" includes not only the above-mentioned railways but also roadways (general motorways, bicycle paths, expressways, etc.), sidewalks, promenades, and concrete guideways. Furthermore, between multiple parallel roads (for example, parallel inbound and outbound lanes or multiple parallel promenades), vertical penetrations such as gaps or openings may be formed, and the above-mentioned hanging noise reduction device may be installed in such vertical penetrations as a measure against noise leaking downward. <6> The hanging type sound reduction device main body 3 to be attached to the opening 7 in Figure 11 may be a rectangular cylindrical shape in plan view, as shown in Figures 6(A) and (B), or may be a square cylindrical shape in plan view or a circular cylindrical shape in plan view.In the case of a rectangular cylindrical shape, the slits and sound absorbing material may be arranged on at least one of the four sides, or on either one of the long sides or short sides, or on both sides, in plan view.

[0035] As mentioned above, although reference numerals are used for the purpose of easy comparison with the drawings, the present invention is not limited to the configurations shown in the drawings, and it goes without saying that the present invention can be embodied in various forms without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0036] 1 floorboard 2 viaduct 3 Hanging type sound reduction device body 4 Noise passage section 5 Protruding plate 6. Sound-absorbing materials 7 Openings 8 Slit protection film 10 Hanging sound reduction device 11 Slit

Claims

1. A cylindrical suspended noise reduction device that forms a noise passage below an opening in a floor surface of an elevated bridge, A plurality of protruding plates, each having a slit extending in a direction perpendicular to the longitudinal direction of the noise passage portion, are provided in a vertically longitudinal direction of the noise passage portion, and protrude from a cylindrical suspension type sound reduction device body toward the noise passage portion; A hanging type sound reduction device in which sound absorbing material is attached to the inner surface of the hanging type sound reduction device body in the remaining portion in the vertical longitudinal direction of the noise passage portion.

2. 2. The suspension-type noise reduction device according to claim 1, wherein the viaduct is for railway vehicles having tracks formed on its deck, and the opening is a snow removal opening for allowing fallen snow to fall and be discharged from the tracks.

3. 3. A hanging type sound deadening device according to claim 2, wherein said plurality of protruding plates are provided with a breathable slit protection film for covering the slits.

4. 4. The hanging type sound deadening device according to claim 3, wherein the slit protective film is made of a porous sintered aluminum material.

5. 3. The suspension type sound reduction device according to claim 2, wherein each of said plurality of protruding plates is installed with its tip end inclined downward.

6. An opening is provided in the floor surface, and a cylindrical hanging type sound-reducing device is provided below the opening to form a noise passageway. The hanging type sound-reducing device is constructed by providing a plurality of protruding plates that form slits along a direction perpendicular to the longitudinal direction of the noise passageway in a portion of the vertical longitudinal direction of the noise passageway, and protruding from the cylindrical hanging type sound-reducing device body toward the noise passageway; A viaduct in which sound-absorbing material is attached to the inner surface of the main body of the hanging type sound reduction device in the remaining portion in the vertical longitudinal direction of the noise passage portion.

7. 7. The viaduct according to claim 6, wherein a track for railway vehicles is formed on the floor surface, and the opening is a snow removal opening for allowing fallen snow to fall and be discharged from the track.

8. providing vertical penetrations that form openings or gaps between the multiple parallel roads; A cylindrical hanging type sound-reducing device is provided at the bottom of the vertical through-hole to form a noise passage, and the hanging type sound-reducing device is constructed by providing a plurality of protruding plates that form slits along a direction perpendicular to the longitudinal direction of a part of the vertical longitudinal direction of the noise passage, protruding from the cylindrical hanging type sound-reducing device main body toward the noise passage, A viaduct in which sound-absorbing material is attached to the inner surface of the main body of the hanging type sound reduction device in the remaining portion in the vertical longitudinal direction of the noise passage portion.

9. 9. The viaduct according to claim 8, wherein the road is at least one type selected from the group consisting of an ordinary roadway, an expressway, a railway, a concrete guideway, a sidewalk, and a promenade.

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