JPS6350500B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a sound-absorbing stone cladding method that is characterized in that the space behind the stone, which is a dead space in conventional dry construction methods, is used to create a resonator exclusively for the low frequency range. The following problems arise when designing and constructing a large-scale concert hall with a seating capacity of approximately 2,000 people and a reverberation time of 2 seconds. In order to ensure a reverberation time of 2 seconds in an indoor space of ^17,000m3 , ideally the walls of the space should be made of reflective hard finishing material, but only expensive materials such as marble are available, and it is difficult to find suitable materials. It will be difficult to select. Most of the sound absorption in the high frequency range is done by the clothes of the occupants and the unevenness caused by humans, but there is almost no sound absorption effect in the low frequency range. Therefore, the present inventors focused on the resonator that has been used conventionally and proposed the present invention.
Resonators were used in many medieval Danish and Swedish churches and had the ability to adjust the long reverberation times of religious music in churches. The inventor conducted reverberation calculations and model experiments according to conventional methods. Table 1 shows the required area and approximate number of bass sound absorbing structures when the air volume is ^17000m3 .
FIGS. 1, 2, 3, and 4 show the general shapes of a Helmholtz resonator, a slit resonator, a slit-like resonant sound absorber, and a perforated resonant sound absorber, respectively.

[Table] However, as is clear from Table 1, even a Helmholtz type resonator requires at least 5000 resonators (in this case, the reverberation time in the acoustically low range will be a little longer than the target value), and sufficient bass processing can be achieved. It was determined that 15,000 pieces would be required if the design was made.
The design of 15,000 randomly arranged holes in a concert hall is so unusual that there is no way it could be adopted. In addition, it is not easy to fix it in a specified position in a manner that can withstand the vibrations and lateral pressure of the concrete during concrete pouring, and it is also disadvantageous from an economic point of view. Figure 5 shows the basic principle of a resonator.A resonator is constructed by connecting a hollow part V with a neck V', and it is embedded in a rigid wall and does not move when a sound wave is projected. The dimensions of each part of the resonator must be sufficiently small compared to the wavelength, and when a sound wave is incident on the resonator, the air l ₀ and m in the network begin to vibrate according to the frequency of the sound wave. Therefore, the air in the cavity repeats regular compression and expansion motions like a spring. Kinetic energy is concentrated in the net, whereas potential energy appears in the cavity. As a result of intensive research on these, the inventors found that the 6th
As shown in the figure, the neck V' of the resonator was replaced with a slit S instead of a cylinder, and the independent box B system for one unit was also abolished in favor of a structure in which the panel P was brought out from the wall surface. That is, the framework of the present invention is characterized in that a sound-absorbing material such as sound-absorbing glass wool is pre-applied to the dry stone installation method, and an improved slit-type resonator is incorporated into the panel installation method. The dry stone pasting method for building walls requires that the back side of the stone be 80mm thick because of the installation of hardware and the tightening of bolts.
mm or more, and this space behind the stone becomes a dead space.In contrast, the present invention uses this space behind the stone to create a resonator with a slit width of the dimensions confirmed by acoustic experiments. It has particular characteristics. In addition, sound-absorbing materials such as glass wool can be attached to the panels in advance, reducing the number of on-site work hours and ensuring high construction accuracy. In addition, the space behind the stone can be used for air conditioning as needed, and the width of the slit and the entrance and exit of the mounting panel into the building frame can be easily adjusted by adjusting the dimensions of the supporting hardware in the dry construction method. Installation speed can be significantly reduced compared to wet construction methods. To explain the present invention in more detail, the present invention
A sound-absorbing material is layered in advance on the back side of a fiber-reinforced gypsum slab with a size of 15 to 45 mm and a specific gravity of 1.65 ± 0.4, and this is attached to the building wall using a dry method so as to maintain a space behind the stone of 50 to 200 mm. 50 to 150 mm communicating with the space behind the stone on at least one edge of the plate
It is characterized by forming a resonator by providing slits, making the surface of the plate a diffuser for reflecting high-frequency ranges, and at the same time, the slits significantly absorb low-frequency sounds. The present invention will now be described in further detail. The fiber reinforced gypsum board used in the present invention is
Add 35 to 45 parts of water to α-type hemihydrate gypsum, 2 parts of water resistance enhancer, E
Contains 0.1 to 1.0 (parts by weight) of short glass fibers, the surface of which is coated and impregnated with a printed photocurable resin and cured with ultraviolet light. Co., Ltd. (product name) is used. This panel not only has an excellent design effect, but is also nonflammable, can be manufactured in large versions, and can be freely designed with wall thickness as required. Moreover, the specific gravity is around 1.65, and it is 900 x 600 x 20 mm.
The weight of each plate is just under 18 kg and it is easy to handle, so it can be used even when working at heights.
It is safer than traditional stone-pasting work. Further E
Because glass fiber is mixed in, the bending strength is low even though the base material is made of plaster.
It also has excellent impact resistance, tenacity, and thick handle strength. When testing the strength of thick handles, conventional natural stone materials have large variations, and safety checks for areas such as grains and joints that correspond to knot holes and cracks in wood are complicated. Because it is an industrial product, there is very little variation, and due to the action of glass fibers, even after the panel is broken, it has the ability to hold up to about twice its own weight by entwining the fibers, which is not seen with stone. It was found that safety can be expected in the plastic region. The surface of the panel is hard and has a specific gravity of 1.65, so it was confirmed in a 15m ² full-scale experiment that it is useful for reflecting high-frequency sounds. This makes the panel an alternative material that takes advantage of the characteristics of natural marble, which was an ideal material for concert reflective walls. Furthermore, by forming only the end portion of the panel to be thick, the thick handle strength can be further increased and the weight of the panel can be reduced. As the sound absorbing material used in the present invention, glass wool with a wall thickness of 25 mm±20 mm and a density of 32±5 Kg/m ³ was effective in acoustic tests. However, the sound absorbing material changes depending on the space behind the stone and the slit width, and in principle sound absorbing materials other than glass wool can also be used. Further, the metal used in the present invention is preferably one that does not usually rust, and SUS304 stainless steel, brass, aluminum alloy, or plated steel is used. A slit in the present invention basically refers to a gap that occurs at the joint between panels, and the width of this slit can be changed depending on the mounting position of the supporting metal. The slits are arranged in both the vertical and horizontal directions, or in either direction, and have a width of 50 to 150 mm. In special cases, at least two or more openings are provided in the panel in parallel with the slits, and these are provided by drilling with a drill or the like, or by embedding foamed polystyrene or the like in advance during panel manufacture. The space behind the stone in the present invention refers to the space on the back side of the panel, and the back of the stone is lined with glass wool to further improve sound absorption efficiency. As explained above, the present invention makes full use of the seismic resistance and construction speed characteristics of the dry construction method, utilizes the space behind the stones, which is a dead space that has been considered a drawback in the past, as a resonator, and also uses sound-absorbing materials in advance with panels at the factory. By lining the slit with the slit, it saves on-site work, and the width of the slit can be adjusted using the support metal used in the dry method. Furthermore, since concert halls are originally windowless and are public buildings in which many lives are taken care of, by finishing the interior with the above-mentioned panels, which are noncombustible materials, safety in the event of a disaster is increased. In addition, as a result of the thick handle strength test, the panel 1mm
The proof stress per thickness is determined by P (Kg) = 5.5t±4.6 (t: effective thickness of the thick stone in mm), and it can sufficiently follow earthquakes that involve 1/150 interstory displacement, and the area around the thick stone The probability of damage to the panel is extremely low at 6/100,000, and even if there is a 6/100,000 chance that a crack will occur in the panel due to the entangled effect of the short glass fibers mixed in the base material, it will still weigh twice its own weight. It maintains the strength of
This ensures high safety. Furthermore, the present invention can be used with dry construction methods such as 3-point or 4-point support, hanging construction methods, and drilling, as long as the space behind the stone can be secured. Eliminating the need for a high safety factor, the panel's own weight is 2/2 that of stone.
3, it is lightweight and has high tenacity due to the glass fiber.
In addition, the supporting metal fittings for the interior can be used simply by dipping and plating, making it very economical and easy to install. Next, examples of the present invention will be given. Example 1 Holes 2 were pre-drilled at the factory at four locations at the end of a fiber-reinforced gypsum board 1 (Gyalston, already mentioned) formed into a flat plate of 600 x 900 x 20 mm, and then the length
A thick-handled SUS304 stainless steel pin 3 with a diameter of 40 mm and a diameter of 6 mm was planted and adhered with epoxy adhesive, and a glass wool mat 4 with a thickness of 25 mm and a density of 32 kg/m ³ (Asahi Fiber Glass Co., Ltd. product) was installed as a sound absorbing material. ) was bonded to the surface of the fiber-reinforced gypsum board 1. On the other hand, a mounting hardware 6 with a groove-shaped cross section is anchored to the inner wall 5 of a reinforced concrete concert hall via anchoring hardware 7, and thick pins 3 are attached to both leg pieces of the mounting hardware 6 while adjusting the entrance and exit of the plate 1. A flat plate 8, which was integrally fixed to the plate 8, was fixed, and each plate 1 was attached to the inner wall 5 so as to have a required clearance 9 between the stones.
(See Figure 7) This method reduces the construction speed to 1/3 compared to the conventional wet construction method, reduces the number of man-hours on site by installing the sound-absorbing material at the factory, and is faster than conventional treatment. There was no need for leftover materials, and the reliability of the construction work increased. Also, for acoustics, the vertical joints are installed with a 100mm gap,
A resonator is constructed by setting the space behind the stone to 90 mm, and thus the earthquake resistance of the dry method and the conversion of the space behind the stone into a resonator with glass wool can be achieved at the same time. Example 2 Figures 8A and 9A show the fiber-reinforced gypsum board 1
Another embodiment of the present invention is shown in which the board 1 is formed into a U-shaped cross section, and a glass wool mat 4 is laminated in layers so as to partially fit into the concave part of the back surface of the board 1, thus taking up a large space behind the stone and reducing the weight of the panel. In addition, even if the thickness of the plate becomes thinner, the thick handle portion becomes thicker, thereby improving the yield strength of the thick handle. In addition, FIGS. 8B and 9B show the parts corresponding to FIGS. 8A and 9A of the fiber-reinforced gypsum board 1 of Example 1 for comparison, and the dimensions (mm) of each part are also shown. has been done. Figures 10 and 11 show part of the measurement data for determining the width of the slit. Figures A and B in Figure 10 respectively show cases where the fiber-reinforced gypsum board is not lined with glass wool and the slit width is 73mm and 17
C and D in FIG. 11 show cases in which the fiber-reinforced gypsum board is lined with glass wool and the slit widths are 73 mm and 17 mm, respectively. As is clear from this, the larger the slit width is, the more advantageous it is, and lining it with glass wool improves its sound absorption coefficient and is the most difficult to process.
The ultra-low frequency range of 125Hz exhibits a high sound absorption coefficient of 0.42, and as the frequency increases to 250, 500, and 1000Hz, the sound absorption coefficient decreases mildly, which is considered difficult from an acoustic standpoint and could not be achieved with conventional methods. We were able to satisfy the reverberation time of 2 seconds. Furthermore, there is a slight correlation between the volume of the space behind the stone and the width of the slit, and it has been found that the case where the space behind the stone is 50 to 200 mm and the slit width is 50 to 150 mm is most preferable. Although the present invention has been described above with reference to embodiments, the present invention is, of course, not limited to such embodiments, and can be modified in various ways without departing from the spirit of the present invention. .

[Brief explanation of drawings]

Figures 1 to 4 are explanatory diagrams of the low-temperature sound absorbing structure shown in Table 1, Figures 5 a, b, and c are diagrams explaining the principle of a resonator, and Figure 6 is a slope showing the shape of the resonator. In the figure, the left side shows a conventional resonator, and the right side shows a resonator constructed according to the present invention. FIG. 7 is a longitudinal sectional view showing the implementation status of the method of the present invention;
A, FIG. 9A is a vertical cross-sectional view and an enlarged view of the main parts showing another example of the fiber-reinforced gypsum board used in the present invention, and FIG.
B and FIG. 9B show parts corresponding to FIGS. 8A and 9A of the embodiment shown in FIG.
Figures 1 and 11 are charts showing the results of measuring the low sound absorption ability of various fiber-reinforced gypsum slabs. 1...Fiber-reinforced gypsum board, 4...Glass wool mat, 9...Stone back space, S...Slit.

Claims (1)

[Claims] 1 A gypsum slab with a layer of sound-absorbing material layered on the back side and reinforced with fibers is attached to the inner wall surface of the building by a dry method so as to leave a space behind the stone, and at least one edge of the slab is provided with the space. A sound-absorbing stone pasting method characterized in that a resonator is formed by providing a slit that communicates with the plate, the slit portion is used as a low-frequency sound absorbing part, and the surface of the plate is used as a diffuser that reflects high-frequency sound.