JP3928947B2 - Reduction structure of rain noise on roof surface - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure for reducing rain noise generated by raindrops colliding with a roof surface during rainfall.
[0002]
[Prior art]
In recent years, large-scale structures such as gymnasiums, baseball fields, soccer fields, athletic fields, pavilion facilities, multipurpose public facilities, so-called dome structures, tent structures (membrane structures), and space structures such as frame structures Is actively built. In these large-scale structures, a thin metal plate such as stainless steel, titanium, or steel, or a film material obtained by coating a glass fiber cloth with a tetrafluoroethylene resin is used as a roof material because of a demand for weight reduction.
[0003]
However, in the case of these thin metal plates and film materials introduced with tension, there has been a problem that during rain, a large collision sound is transmitted to the indoor side due to the collision of raindrops, and the noise is intense.
[0004]
In particular, in the case of building structures built for the purpose of concerts, events, meetings, etc., rain noise is a significant obstacle, such as inability to hear music, announcements and conversations.
[0005]
Conventionally, in order to reduce rainfall noise, the metal plate roof is laminated with a piece of wood / wooden cement board on the inner surface side of the metal plate roof, as shown in Patent Documents 1 and 2 below. It is practiced to install a sound absorbing material, a sound insulating material, etc. on the entire surface without any gaps in the indoor side.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-292566 [Patent Document 2]
JP-A-10-292567 [0007]
[Problems to be solved by the invention]
However, all of the above-mentioned methods are applied to a metal plate roof, and it is structurally difficult to apply these methods to a roof made of a membrane material because the strength of the membrane material is weak. There is a problem that light transmitted from the material is blocked, and the daylighting function inherent to the film material is impaired.
[0008]
On the other hand, as a method considering the daylighting property of the film material, for example, a method of stretching another film material with a space inside the film material, or a ceiling material with a transparent material such as glass. The method of covering etc. can be considered. However, in the former case, since the sound transmission loss of the membrane material itself is small, an effective sound insulation effect cannot be obtained, and in the latter case, it is difficult to adopt because the construction cost increases and it is difficult to say that both are effective methods. .
[0009]
On the other hand, depending on the structure, rain noise may be regarded as a problem after starting operation, and it is possible to implement rain noise countermeasures for existing roofs only by construction from the outside without stopping the use of the building. It is hoped that there will be.
[0010]
Therefore, the main problem of the present invention is that it has the advantage of maintaining daylighting, and can be applied not only to a metal roof but also to a roof membrane, and the construction cost can be low, and sufficient noise reduction is possible. It is another object of the present invention to provide a structure for reducing rain noise on a roof surface that is effective and can be applied to an existing roof by construction from the outside.
[0011]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, in the present invention according to claim 1, in a building structure in which a membrane material or a metal plate is used as a roof material, a space having a predetermined width is provided on the upper surface side of the membrane roof or the metal plate roof. Rain noise on the roof surface characterized in that a mesh membrane having a large number of openings formed in an open state is stretched, and the mesh diameter of the mesh membrane is 5.0 mm or less and the aperture ratio is 60% or less. A reduced structure is provided.
[0012]
In the first aspect of the present invention, the mesh membrane is stretched on the upper surface side of the metal plate roof or the membrane roof with a space left open. Therefore, most or all of the raindrops collide with the mesh membrane, and the impact of raindrops on the metal plate roof or membrane roof is reduced or dispersed, or almost completely eliminated depending on the mesh diameter. When raindrops collide with the mesh membrane, the occurrence of vibration is suppressed, and the generation of vibration noise is greatly suppressed due to the characteristics that vibration is difficult to transmit and the vibration is diffused from the opening. As a result, the generation of vibration noise on the metal plate roof and the membrane roof can be remarkably reduced.
[0013]
In addition, the mesh membrane is arranged in a state separated from the metal plate roof or the membrane roof, and since vibration is released from the opening of the mesh membrane, the sound vibration transmitted to the metal plate roof or membrane roof is reduced. Therefore, it is possible to greatly reduce noise transmitted from the metal plate roof or the membrane roof to the inside. Furthermore, if it is a mesh film | membrane, even if it is after construction, it will be able to fully maintain the daylighting property. The introduction of tension into the mesh membrane is preferably avoided so that excessive tension is not introduced in order to suppress the occurrence of vibration, and the tension is such that slack occurs and does not contact the metal plate roof or membrane roof surface.
[0014]
In addition, in the case of the present invention, even if it is an existing structure, it is only necessary to add a mesh membrane to the roof surface. Even if it is not temporarily suspended, it can be constructed by construction from the outside while in service. In addition, the construction cost can be kept lower than the installation of glass or a transparent resin plate, and a sufficient noise reduction effect can be obtained as verified in Examples described later.
[0015]
The mesh film has a mesh diameter of 5.0 mm or less and an opening ratio of 60% or less . If before Symbol bore diameter and opening ratio above range mesh film, it is what can be expected differ substantially 15~25dB about more noise reduction effect by the frequency band.
[0016]
As the invention according to claim 2, wherein the mesh layer is reduced structure of rain noise at the roof surface according to claim 1 Symbol mounting made of glass fibers resin coating is provided. Since the mesh membrane is also required to have a performance as a permanent structure, it is desirable to use a resin-coated glass fiber cloth so as to satisfy durability, water resistance, and corrosion resistance. Among the resins, those coated with a tetrafluoroethylene resin are desirable.
[0017]
According to a third aspect of the present invention, rope-like spacer members are disposed at predetermined intervals along the upper surface of the membrane roof or the metal plate roof, and a small piece membrane material for fixing is provided along the longitudinal direction on the rope-like spacer member. Provided at predetermined intervals,
The fixing small piece film material includes a rope winding portion through which the rope-shaped spacer member is inserted, and a fixing flap portion extending from the rope winding portion, and the fixing flap portion is the mesh film. by being joined to the upper surface side of the mesh film membrane roof or metal plate roofs, rainfall in the roof surface according to claim 1, 2 or that is stretched in a state in which a space of a predetermined width A noise reduction structure is provided. Although it shows an example of the tension structure of the mesh film, in this case, the small piece film material for fixing is previously bonded to a predetermined portion on the back side of the mesh film by welding or the like at the time of construction. After installing the rope-like spacer member through the rope winding part of the fixing small piece membrane material at the factory stage or before erection, it is stretched over the existing roof surface at once, and the end of the mesh membrane is welded to the existing roof surface, etc. Construction is possible by fixing with The rope-like spacer member is preferably divided at various places so as not to impair drainage.
[0018]
According to a fourth aspect of the present invention, there is provided the structure for reducing rain noise on the roof surface according to the third aspect, wherein the rope-shaped spacer member is made of a rubber-based elastic material. By using the rubber-like elastic material for the rope-like spacer member, it is possible to reduce the vibration of the mesh membrane from being transmitted to the metal plate roof or the membrane roof via the rope-like spacer member.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view of a membrane structure 1 to which a structure for reducing rainfall noise on a roof surface according to the present invention is applied, and FIG. 2 is a plan view of an essential part thereof.
[0020]
As shown in FIG. 1, the membrane structure 1 is a dome-like membrane structure having a substantially elliptical planar shape, and a plurality of arcuate chord members 8, 8... Are arranged along the major axis P direction. In addition, diagonal members 9, 9... Are arranged so as to form a triangular truss between the arcuate chord members 8, 8,. A circumferential chord member 10 is disposed on the outer periphery of the dome-shaped membrane structure 1.
[0021]
A roof membrane 2 in which a glass fiber cloth is coated with a tetrafluoroethylene resin is stretched over the outer surface side of the dome-shaped ceiling frame composed of the arcuate chord material 8... It is fixed on the outside of the circumferential chord 10. In detail, as shown in FIG. 7, the fixing of the roof membrane 2 is performed by fixing a fixing plate 13 to the outer side portion of the circumferential chord member 10 with the upper surface side as the same surface. It is fixed by a fixing metal fitting 14 that holds the end of the roof membrane 2 at a position beyond it. A draining panel 11 is continuously provided on the fixing plate 13 over the entire circumference of the dome-shaped membrane structure 1 in order to discharge rainwater flowing down from the roof membrane 2. Further, an inner membrane 16 is stretched inside the roof membrane 2 so as to conceal the respective chord materials such as the arcuate chord material 8.
[0022]
On the upper surface side of the roof membrane 2, a mesh membrane 3 is stretched with a space K having a predetermined width as shown in FIG. 3 in order to reduce rain noise. As shown in FIG. 2, the mesh film 3 is a film material in which a large number of openings are formed in a lattice shape, for example, so as to satisfy durability, water resistance, and corrosion resistance as a permanent structure. A glass fiber coated with a resin, preferably a tetrafluoroethylene resin, is preferably used.
[0023]
The mesh diameter s of the mesh film 3 is 5.0 mm or less, preferably 4.0 mm or less, more preferably 3.0 mm or less, and still more preferably in order to sufficiently exhibit the noise reduction effect from the experimental results described later. 2.5 mm or less. The mesh opening ratio is 60% or less, preferably 50% or less, more preferably 40% or less, and still more preferably 30% or less.
[0024]
Next, the attachment structure of the mesh membrane 3 to the roof membrane 2 will be described in detail.
As shown in FIGS. 2 to 4, in the present roof structure, in order to form a space K between the roof membrane 2 and the mesh membrane 3, the rope-like spacer member 4 is interposed therebetween. A mesh film 3 is provided. Specifically, rope-like spacer members 4 are arranged at predetermined intervals L, L... Along the upper surface of the roof membrane 2, and a small piece film material 5 for fixing is attached to the rope-like spacer member 4 in the longitudinal direction. Are provided at predetermined intervals. As shown in detail in FIG. 4, the small piece film material 5 for fixing includes a rope winding portion 5a through which the rope-shaped spacer member 4 is inserted, and a fixing flap extending from the rope winding portion 5a. Part 5b, and the fixing flap part 5b is joined to the mesh film 3 by thermal welding or the like, so that the mesh film 3 has a space K of a predetermined width on the upper surface side of the roof film 2. It is stretched in a state. The rope-like spacer member 4 is made of natural rubber or synthetic rubber so as to be flexible along the curved membrane surface and not transmit vibration from the mesh membrane 3 to the roof membrane 2. It is desirable to use a rubber-based elastic material.
[0025]
The width F of the space K (≈the diameter of the rope-shaped spacer member 4) is preferably 20 to 50 mm, and preferably about 25 to 35 mm. The spacing L between the rope-shaped spacer members 4 is the mesh film 3. It is desirable that the distance be such that it does not contact the roof membrane 2, for example, about 300 mm to 500 mm.
[0026]
Although the mesh film 3 can cover the entire upper surface of the dome structure with one mesh film, in this example, as shown in FIG. 1, the dome upper surface is divided into three in the major axis P direction, Each area is covered with divided mesh films 3A, 3B, and 3C.
[0027]
When the mesh film 3 is constructed, the small piece film material 5 for fixing is bonded to a predetermined portion on the back side of the mesh film 3 in advance by welding or the like, and the rope-like spacer member 4 is fixed before factory installation or before installation. After inserting and attaching to the rope winding part 5a of the small piece membrane material 5, it covers the upper surface of the roof membrane 2, and as shown in FIG. 5 and FIG. 7, the end 3a of the mesh membrane 3 is attached to the roof membrane. 2 is fixed by heat welding directly or through an intermediate material such as a fixing flap. In addition, as shown in FIG. 6, the rope-like spacer member 4 is divided at various places so as not to impede drainage.
[0028]
Although the membrane structure 1 using the membrane material on the roof surface has been described above, the present invention can be similarly applied to a structure using a metal plate such as stainless steel, titanium, or steel as the roof material. .
[0029]
【Example】
In this example, the effect of the rain noise reduction structure according to the present invention was verified by experiments.
[0030]
In the experiment, a raindrop generator with a large number of nozzles was used, and in the case of only the membrane (reference case), a 30 mm space was provided on the upper surface of the membrane, and a mesh membrane with a mesh diameter of 1 mm and an aperture ratio of 20% was provided. In some cases (test condition 1), a 30 mm space is provided on the upper surface of the film and a mesh film having a mesh diameter of 2 mm and an aperture ratio of 15% is provided (test condition 2), and a 30 mm space is provided on the upper surface of the film. For the three conditions (test condition 3) when a mesh film with a mesh diameter of 5 mm and an aperture ratio of 61% is provided (rain condition test), a rain test is performed for each of the cases where large raindrops are generated and small raindrops are generated. , Measure the noise level (sound pressure level) by the measurement method based on JIS Z 8731, the measurement result is the horizontal axis is frequency (1/3 octave band center frequency), and the vertical axis is the case of only membrane material Decrease in sound pressure level (sound Pressure level relative value) was plotted in a graph. The results are shown in FIGS. 8 shows a case where large raindrops are generated, and FIG. 9 shows a case where small raindrops are generated.
[0031]
As apparent from FIGS. 8 and 9, when the reduced structure of the present invention in which a mesh film is stretched with a space left on the upper surface side of the film, the noise level due to rainfall is significantly reduced. I understand that
[0032]
Next, in order to grasp the optimum values of the mesh diameter and aperture ratio of the mesh membrane, as shown in FIG. 10, the horizontal axis is the mesh diameter (mm) and the vertical axis is the sound pressure level for each frequency band. Plotting the relative value (dB) and the graph with the horizontal axis as mesh aperture ratio (%) and the vertical axis as sound pressure level relative value (dB) as shown in FIG. drew.
[0033]
As a result, it was found that the mesh diameter (mm) should be 5.0 mm or less, preferably 3 mm or less, more preferably 2.5 mm or less. Further, it has been found that the mesh opening ratio (%) may be 60% or less, preferably 40% or less, and more preferably 30% or less. It was found that a noise reduction effect of about 15 to 25 dB or more can be expected by using such a numerical range, although it varies depending on the frequency band.
[0034]
【The invention's effect】
As described above in detail, according to the present invention, since it has advantages such as maintaining daylighting, it can be applied not only to a metal roof but also to a roof membrane. In addition, the construction cost can be reduced and a sufficient noise reduction effect can be obtained. Furthermore, since construction can be performed on the existing roof by construction from the outdoor side, construction can be performed without stopping the use of the building even if the building structure is in service.
[Brief description of the drawings]
FIG. 1 is a plan view of a membrane structure 1 to which a structure for reducing rainfall noise on a roof surface according to the present invention is applied.
FIG. 2 is a plan view of an essential part thereof.
FIG. 3 is a view taken along the line III-III.
FIG. 4 is an enlarged view of FIG. 2;
FIG. 5 is an enlarged cross-sectional view of an essential part showing an end fixing part of the mesh film 3 (as viewed along arrows VV in FIG. 1).
6 is an enlarged cross-sectional view of an essential part showing an intermediate part of the mesh membrane (as viewed in the direction of arrows VI-VI in FIG. 1).
7 is a cross-sectional view showing an end film fixing portion of the film structure 1. FIG.
FIG. 8 is a graph of relative sound pressure levels when large raindrops are generated.
FIG. 9 is a graph of relative sound pressure levels when small raindrops are generated.
FIG. 10 is a graph showing a change in relative sound pressure level when the mesh diameter is changed.
FIG. 11 is a graph showing a change in relative value of sound pressure level when the mesh aperture ratio is changed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Membrane structure, 2 ... Roof membrane, 3 ... Mesh membrane, 4 ... Rope-like spacer member, 5 ... Small piece membrane material for fixing, 5a ... Rope entrainment part, 5b ... Flap part for fixing, 8 ... Arc-shaped chord material , 9 ... diagonal, 10 ... circumferential chord, 11 ... draining panel, 16 ... inner curtain

Claims (4)

In a building structure in which a membrane material or a metal plate is used as a roofing material, a mesh membrane in which a large number of openings are formed on a top surface side of the membrane roof or the metal plate roof with a space of a predetermined width provided. And a rain noise reduction structure on the roof surface , wherein the mesh membrane has a mesh diameter of 5.0 mm or less and an aperture ratio of 60% or less . The mesh film is reduced structure of rain noise at the roof surface according to claim 1 Symbol mounting made of glass fibers coated with a resin. A rope-shaped spacer member is disposed at a predetermined interval along the upper surface of the membrane roof or the metal plate roof, and a small piece film material for fixing is provided at a predetermined interval along the longitudinal direction on the rope-shaped spacer member,
The fixing small piece film material includes a rope winding portion through which the rope-shaped spacer member is inserted, and a fixing flap portion extending from the rope winding portion, and the fixing flap portion is the mesh film. by being joined to the upper surface side of the mesh film membrane roof or metal plate roofs, rainfall in the roof surface according to claim 1, 2 or that is stretched in a state in which a space of a predetermined width Noise reduction structure. 4. The structure for reducing rainfall noise on a roof surface according to claim 3, wherein the rope-shaped spacer member is made of a rubber-based elastic material.

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