JP2005282321A - Floor structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a floor structure which is suitable for the absorption of air vibrations of a low frequency causing a problem of a heavy floor impact sound. <P>SOLUTION: This floor structure A' is provided with at least one hollow section B, and an opening C for making the hollow section B communicate with an attic space D. This enables the hollow section B to act as a branch pipe-type resonator, and enables the absorption of the air vibrations of the space D. The hollow section B is constituted, for example, by connecting and integrating a top surface plate 2 and an undersurface plate 4 together by means of a connecting member (folded plate 9). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a structure of a floor structure for reducing floor impact sound.

  In apartments such as apartments and apartments where different households live on the upper and lower floors, when children run around and jump, the fall of light objects such as spoons, dragging chairs, etc., impact noise is generated in the downstairs, which is a problem There is.

  Such an impact sound is called a floor impact sound. Among the impact sounds, an impact sound caused by a heavy object falling like a jumping child is called a heavy floor impact sound. The impact sound due to falling may be referred to as a lightweight floor impact sound. Lightweight floor impact sound can be reduced by laying a relatively soft material such as carpet or tatami on the floor surface, but heavy floor impact sound is not easy to take countermeasures because not only the floor but also the structure including the wall vibrates. .

  In order to prevent heavy floor impact sound, generally, a method of increasing the mass of the floor, such as a concrete plate or a foamed concrete plate having a thickness of 100 to 200 mm, is employed. However, if such a weight structure is adopted, it is necessary to increase the rigidity and strength of the walls and pillars that support the weight of the floor, and the overall weight of the building structure becomes enormous. The pillars will need to be stronger.

  Therefore, the inventors of the present application investigated the vibration propagation path inside the building structure when the heavy floor impact sound was generated, and proceeded earnestly on a method for reducing the heavy floor impact sound without increasing the floor weight. . As a result, the vibration propagation path from the floor to the ceiling includes: [1] floor vibration-ceiling air vibration-ceiling vibration; [2] floor vibration-beam vibration-ceiling suspension member vibration-ceiling vibration; [3] floor There are vibrations-beam vibrations-wall vibrations, of which [2] and [3] were found to be greatly affected by solid propagation. Based on these survey results, we found that vibration isolation between the floor and the beam is the most effective way to reduce the vibration of the ceiling and walls.

  However, if the floor is anti-vibrated and supported on the beam by so-called spring elements such as foamed urethane, rubber, coil springs, etc. to insulate the floor and the beam, the vibration transmitted from the floor to the beam can certainly be greatly reduced. Instead, floor vibration increases and the air propagation of [1] increases. Therefore, even if [2] and [3] solid propagation on the ceiling and wall can be reduced by vibration isolation between the floor and the beam, [1] air propagation to the ceiling is increased, and the radiated sound from the ceiling is effective. It was not possible to reduce it.

Therefore, it is conceivable to reduce the air propagation of [1] using a resonator, for example. For example, Patent Documents 1 and 2 disclose a method for absorbing floor impact sound using a resonator. Patent Document 1 discloses a configuration in which a sound insulation device is installed across beams that support a floor, and a vibration insulating material is interposed between the floor and the beam and between the beam and the sound insulation device. Patent Document 2 discloses a configuration in which a branch-pipe resonator is formed by providing an opening in a column having a hollow portion disposed in a wall.
JP-A-8-319680 JP 2002-348985 A

However, even if a vibration insulating material is interposed between the floor and the beam and between the beam and the sound insulation device as in Patent Document 1, vibration transmitted from the floor to the sound insulation device cannot be completely eliminated. Therefore, in the sound insulation device installed between the beams, there is a possibility that the substrate on which the open container is fixed is amplified by the vibration of the beam, and the substrate becomes a new sound pressure radiation surface to increase noise. Further, in the apartment house as described above, the height of the beam is practically about 200 millimeters, and the volume V of the open container is approximately 0.1 × 0.1 × 0.1 = 10 ^{−3 at most.} The cubic meter and the diameter d of the opening must be about 0.01 to 0.05 meters. Substituting this into the equation of f ₀ = (C / 2π) · √ (d / V) results in 171-183 Hz, and thus effectively absorbs sound with a frequency of 45-90 Hz, which is a problem with heavy floor impact sound. It is difficult.

  Moreover, in the structure which forms a branch pipe type resonator by providing an opening part in the pillar which has the hollow part arrange | positioned in the wall like patent document 2, the height of a pillar is dependent on the floor height of a dwelling unit. Therefore, the frequency that can be absorbed by the resonator is limited. In addition, when it is necessary to ensure the fire resistance between adjacent dwelling units such as the boundary wall, special measures are required to prevent the flame from entering the opening provided in the pillar having the hollow portion. End up.

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  ◆ According to an aspect of the present invention, there is provided a floor structure provided with at least one hollow portion and provided with an opening for communicating the hollow portion with a ceiling space.

  Thereby, a hollow part can be made to act as a branch pipe type resonator, and the air vibration of ceiling back space can be absorbed. In particular, it is suitable for absorbing air vibration at a low frequency, which is a problem with heavy floor impact sound.

  In the floor structure described above, it is preferable to install a sound absorbing material in the hollow portion.

  Thereby, the frequency which the said hollow part absorbs can be given width. In addition, air vibration at a high frequency that cannot be absorbed by the resonator can be absorbed by the sound absorbing material.

  The above floor structure is preferably composed of a beam member having at least one hollow portion and a face material.

  Thereby, a branch pipe type resonator can be formed without adding a new member by using the hollow part inside a beam member. Therefore, the structure is simplified.

  In the floor structure described above, it is preferable that the upper surface plate and the lower surface plate are joined together by a joining member.

  Thereby, a hollow part can be simply comprised between an upper surface board and a lower surface board.

  In the floor structure, it is preferable that the coupling member is a mold material.

  Thereby, the cross-sectional shape and dimension of a coupling member can be made uniform. Moreover, mass production is easy and the cost can be reduced.

  In the floor structure, it is preferable that the coupling member is a folded plate.

  Thereby, a hollow part can be comprised easily.

  In the floor structure, it is preferable to provide the opening in the bottom plate or the coupling member.

  Thereby, a branch pipe type resonator can be formed with a simple structure.

  In the floor structure described above, it is preferable that the top plate and the mold or folded plate are combined.

  Thereby, the branch pipe (hollow part) which acts as a branch pipe type resonator can be formed with a simple configuration.

  In the floor structure described above, it is preferable to provide a partition plate at an arbitrary position in the longitudinal direction of the hollow portion.

  Thereby, the frequency of the resonance tube can be easily set by changing the position of the partition plate. Therefore, sound absorption design is easy.

  In the floor structure, it is preferable that the partition plate is provided with an opening smaller than the cross-sectional area of the hollow portion.

  As a result, a so-called hybrid resonator in which two branch-type and volume-type resonators are combined can be formed.

  In the floor structure described above, it is preferable to have a plurality of the hollow portions and to change the position of the partition plate in each hollow portion.

  Thereby, a plurality of resonators having different resonance frequencies can be configured. Therefore, even when air vibrations are simultaneously generated at different frequencies in the ceiling space, sound can be absorbed effectively.

  In the floor structure described above, at least one or more of the openings communicating with the hollow part constituting the branch pipe resonator for the same frequency are located within the length of one wavelength at the frequency of the floor. It is preferable.

  Thereby, rational sound absorption without unevenness becomes possible.

  In the floor structure, the opening is preferably formed at a position corresponding to the antinode portion of the vibration mode of the floor.

  Thereby, since an opening part will be located in the part with a large sound pressure of a ceiling back, efficient sound absorption is attained.

  Next, four examples of the floor structure as an embodiment of the invention will be described with reference to FIGS.

  FIG. 1 shows a first example of a floor structure. This floor structure A is composed of a joist 1 as a beam member and an upper surface plate 2 as a face material fixed on the upper side of the joist 1. A plurality of joists 1 are arranged in parallel to each other, and a hollow portion B is formed in each joist 1. Reference numeral 6 denotes a frame material for supporting the upper plate 2 together with the joists 1, and reference numeral 8 denotes a ceiling provided on the lower side of the joists 1.

  The joist 1 has an opening C, and the hollow B communicates with the lower ceiling back space D (the space above the ceiling 8) through the opening C. FIG. 1 shows various forms of the opening C. As shown in FIG. 1, the opening C may be formed on the lower surface of the joist 1 or on the side surface of the joist 1. Also good.

With the above structure, the hollow portion B inside the joist 1 can be operated as a resonator. There are two types of resonators: a volume type and a branch pipe type (side branch type). The volume type is a type in which the shape of the hollow part is spatially widened, and the volume of the hollow part is defined as V. When the hole diameter as the opening is d and the speed of sound in the air is C, sound is completely absorbed at the resonance frequency f ₀ = (C / 2π) · √ (d / V). The branch pipe type is a type in which the hollow portion forms a one-end closed acoustic tube having one end opened and the other end closed, and when the length of the tube is L, the resonance frequency f ₀ = nC / 4L is complete. Sound is absorbed. However, n = 1, 3, 5,.

When the hollow part B constitutes the branch pipe type resonator, if the size of one room in a general house is approximately 2.7 m to 4.5 m (although not limited to this), the above When applied to the formula, since n × 340 / (4 × 4.5) ≦ f ₀ ≦ n × 340 / (4 × 2.7), 19 × n ≦ f ₀ ≦ 31 × n. However, n = 1, 3, 5,. Thus, the hollow portion B can absorb air vibration at a low frequency in the ceiling space D, which is a problem particularly with heavy floor impact sound.

  Moreover, in the said embodiment, the joist 1 as a beam member is comprised hollow, and the hollow part B of the inside is made to act as a resonator. Therefore, a branch pipe type resonator (one-end closed acoustic tube) can be formed only by providing the opening C in the joist 1 without adding a new member for exerting a resonance action.

  In addition, it is preferable that the sound absorbing material 4 made of glass wool, polyurethane, or the like is installed inside the hollow portion B. Thereby, the frequency which one hollow part absorbs can be given width. Further, high-frequency air vibration that cannot be absorbed by the resonator can be absorbed by the sound absorbing material 4.

  Further, a partition plate 5 may be provided inside the hollow portion B, and each of the hollow portions B partitioned by the partition plate 5 may communicate with the ceiling space D through the opening C. This configuration is advantageous in the following points. That is, by changing the position of the partition plate 5, the length of the acoustic tube (the length L in the above equation) can be arbitrarily set. Accordingly, the resonance frequency can be arbitrarily adjusted, and sound absorption design is facilitated.

  FIG. 2 (second example) shows various examples when the opening C is provided in the joist 1. As shown in FIG. 2, for example, one end of the joist 1 may be closed with a closing plate 7, and a large rectangular opening C may be formed on the lower surface or side surface of the joist 1. Alternatively, one end of the joist 1 may be cut obliquely, and the resulting oblique rectangular opening may be used as the opening C.

  FIG. 3 shows another example (third example) of the floor structure. This floor structure A ′ has a configuration in which a folded plate (joining member) 9 having a uniform thickness bent in a zigzag manner is provided, and an upper surface plate 2 is provided on the upper surface and a lower surface plate 3 is provided on the lower surface. It has become. The folded plate 9 can be formed by bending a flat plate, or a mold formed by extrusion, for example. By using a mold material, the dimensions of the cross-sectional shape can be made constant, mass production is easy and advantageous in terms of cost.

  3 can be referred to as a configuration in which the upper surface plate 2 and the lower surface plate 3 are combined by the folded plate 9 and integrated. In this configuration, a plurality of triangular prism-shaped hollow portions B are formed side by side between the upper surface plate 2 and the lower surface plate 3 while being adjacent to each other. And since the opening C is formed in the lower surface plate 3, the hollow portion B (at least the hollow portion B surrounded by the folded plate 9 and the lower surface plate 3) acts as a branch pipe type resonator, The same sound absorption effect as that of the configuration shown in FIGS. 1 and 2 can be obtained.

  In FIG. 3, a communication hole E is provided in the folded plate 9 as a coupling member, and the adjacent hollow portions B are communicated with each other through the communication hole E. Specifically, a hollow portion B1 formed between the folded plate 9 and the upper surface plate 2 and a hollow portion B2 formed between the folded plate 9 and the lower surface plate 3 are connected via the communication hole E. Communicate. This corresponds to the fact that the hollow portions B1 and B2 are connected to each other to form a longer acoustic tube. Therefore, lower frequency air vibrations can be absorbed. Alternatively, even when absorbing air vibration of the same frequency, a compact resonator can be obtained.

  In FIG. 3, the lower surface plate 3 may be omitted, and the upper surface plate 2 and the folded plate 9 may be coupled. Also by this, the hollow part B can be formed with a simple configuration. In this case, the opening C may be formed in the folded plate 9.

  FIG. 4 (fourth example) shows various examples when the opening C is provided in the folded plate 9 or the lower surface plate 3. As shown in FIG. 4, for example, one end of the folded plate 9 (one end of the hollow portion B) is closed with the closing plate 7, and a large rectangular opening C is formed in the lower surface plate 3 and the folded plate 9. May be. Further, in addition to the one end of the folded plate 9 being used as the opening C as it is, the folded plate 9 may be cut obliquely, and the resulting oblique opening may be used as the opening C.

  In the example shown in FIG. 4, an opening F is provided in the partition plate 5, and the sectional area of the opening F is smaller than the sectional area of the hollow part B. Thereby, it is also possible to form a so-called hybrid resonator by combining two branch-type and volume-type resonators.

  In order to confirm the sound absorption effect of the floor structure, experiments as shown in FIGS. 5 and 6 were conducted. As shown in FIGS. 5 and 6, a plurality of beams 22 are installed in parallel with each other, and the floor structure A ′ shown in FIG. 3 is placed side by side on the beams 22. A block-like foamed urethane 25 for vibration isolation was interposed between the beam 22 and the floor structure A ′. On the lower surface of the floor structure A ′ (the lower surface plate 3), a large number of substantially circular openings C are opened to communicate with the ceiling space D, and a large number of hollow portions B formed inside the floor structure A ′. It acted as a branch-type resonator. A ceiling base material 24 is suspended from the beam 22 via a hanging bracket 23, and the ceiling 8 is attached to the lower surface of the ceiling base material 24.

  As the material of the floor structure A ', the folded plate 9 is made of steel, the upper plate 2 is made of a wooden plate, and the lower plate 3 is made of a steel plate. Further, the opening C is formed while being shifted to one side in the longitudinal direction of the floor, and various lengths of the hollow portions B (resonator lengths) are changed to absorb various frequencies. The configuration was made possible. In addition, the diameter of the opening part C was made into the magnitude | size of the grade which enters into the mountain and mountain (valley and valley) of the folded plate 9.

  In the above configuration, the tire 21 was dropped from the appropriate height on the floor (upper surface plate 2) on the upper side of the floor structure A 'to generate a heavy floor impact sound. And, the floor vibration in the vicinity of the tire dropping position (point P in FIG. 6), the air vibration in the vicinity of the center of the ceiling (point Q), and the vibration in the vicinity of the center of the ceiling (point R) are respectively measured. The frequency distribution was examined.

  FIG. 7 shows the experimental results as a graph. In the case of air vibration and ceiling vibration, experiments were conducted in two cases, in which the opening C was provided in the lower surface plate 3 and not provided at all, and both results were shown. Referring to FIG. 7, it can be seen that air vibration and ceiling vibration are reduced over a wide range of frequencies when the opening C is provided, compared to when the opening C is not provided.

  In FIG. 8, the same applies to the case where the floor structure A ′ is not vibration-proof supported with respect to the beam 22 (that is, when the foamed urethane 25 is removed and the floor structure A ′ is directly supported by the beam 22). The result of the experiment is shown. As can be seen from FIG. 8, air vibration and ceiling vibration are reduced over a wider range of frequencies when the opening C is provided than when the opening C is not provided.

  Next, the aperture ratio of the opening C will be described with reference to FIG. In general, in the case of a branch-pipe resonator, it is desirable that the opening has the same size as the noise source because a more efficient sound absorption effect is exhibited. For example, when a branch pipe type resonator is attached to a pipe, it is preferable to attach a branch pipe having the same diameter as that of the pipe.

  From this point of view, in the case of the present invention, the air vibration in the ceiling space D is generated with the floor back surface (entire) as the vibration surface. For this reason, the larger the opening area of the branch-pipe resonator, the better. Ideally, the entire floor surface is most desirably open. If the opening area is large, the sound absorption efficiency can be increased, and the resonance frequencies of a plurality of resonators can be easily set. Furthermore, the width of the frequency that can be absorbed by one type of resonator (one opening and one branch pipe) can be increased by expanding the opening area. That is, the branch-pipe resonator is usually effective in a very narrow frequency range centering on the resonance frequency, and the peak of the sound absorption effect is sharp (see the graph in FIG. 9A). However, by increasing the area of the opening, it is possible to soften the sharp peak of the sound absorption effect curve and to have a sound absorption effect with respect to a frequency having a relatively wide width around the resonance frequency (see the graph in FIG. 9B). ).

  From the above, it is desirable to increase the ratio of the area of the opening (opening ratio) to the area of the floor side that is the excitation surface. In other words, if the aperture ratio is small, the frequency range that can be absorbed by one type of resonator only affects the pinpoint of the set frequency, and even if the frequency of the air vibration is slightly different from the set frequency of the resonance tube, the air vibration is reduced. It becomes a situation that hardly absorbs. On the other hand, if the aperture ratio is too large, it is difficult to ensure an effective length as the acoustic tube (length L shown in FIG. 9). On the other hand, if the aperture ratio is too large, the strength of the lower surface plate 3, the folded plate 9, the joist 1, etc. of the floor structure is lowered, and it cannot function as an original structural member.

  From the above, the aperture ratio may be determined in consideration of various matters such as the frequency of the noise desired to be absorbed, the sound absorption volume, and the strength required for the floor. The aperture ratio is usually about several percent to several tens of percent, and is assumed to be 10% to 30% at most.

  10 to 12 show five installation examples of openings C for sound absorption in the floor structure shown in FIG. Each figure of (1)-(5) is a figure seen from the lower side, and the numerical value attached | subjected to the side of each opening C in the figure is the hollow part B connected to the opening C The set frequency of the branch pipe resonator is expressed in units of Hz.

  In the example shown in (1) of FIG. 10, the position of the partition plate 5 is varied to vary the length of the hollow portion B (the length of the branch pipes is varied), and each hollow portion B has various set frequencies. It is made to act as a branch pipe resonator. As a result, as a whole, a sound absorption effect can be obtained in a wide frequency range (40 Hz to 143 Hz). The frequency distribution of the sound absorption effect in the example shown in (1) of FIG. 10 is shown in the upper graph of FIG.

  In the example shown in (2) of FIG. 10, two branch pipe resonators having a set frequency of 40 Hz to 65 Hz are installed. As a result, a good sound absorption effect can be obtained for low sounds such as 40 Hz to 65 Hz.

  10 (1) and (2) uses only the lower hollow portion B (that is, the hollow portion B formed by being surrounded by the folded plate 9 and the lower surface plate 3) as a resonator. Yes. On the other hand, in the example shown in (3) of FIG. 11, similar to (2) of FIG. 10, the sound absorption in the frequency range of 40 Hz to 65 Hz is aimed, but the communication hole E (see FIG. 3) ), And the adjacent hollow portions B and B are connected to each other through the communication hole E to constitute a folded resonator. That is, the upper hollow portion B (hollow portion B formed by being surrounded by the folded plate 9 and the upper surface plate 2) is also configured to be used as a resonator. As a result, the installation length of the resonator can be almost halved, so that twice as many resonators can be installed as compared with the configuration of (2) in FIG. 10, and the sound absorption effect can be enhanced.

  The example shown in (4) of FIG. 11 is a modified example of the configuration of (3), and the opening area of the opening C and the communication hole E is increased (the above-described opening ratio is increased), and the frequency is wide. It aims at the sound absorption effect in the width.

  FIG. 13 is a graph showing a comparison of the sound absorption effect between the configuration of (4) in FIG. 11 and the configuration of (1) in FIG. As is apparent from this graph, when the aperture ratio is increased as in (4), a stable sound absorbing effect can be exhibited even with respect to changes in frequency.

  The example shown in (5) of FIG. 12 is a modified example of (3) of FIG. 11 and has a layout in which a large number of branch pipe resonators having a high set frequency are installed.

Next, a method for setting the position of the opening C will be described with reference to FIG.
Since the noise assumed in the present invention is generated by floor vibration, the magnitude of the noise is determined by the shape of the floor vibration. Here, since the floor vibrates at the natural frequency, the shape of the floor vibration is the vibration mode. Therefore, it is necessary to set the position and the number of the openings C based on the vibration mode.

  14A and 14B schematically show an example of floor vibration and the sound pressure of the ceiling behind it. When the floor vibrates in a mode having a single node in the center as shown in FIG. 14A, the sound pressure in the back of the ceiling also decreases according to the vibration of the floor. And the sound pressure becomes the highest at the location of 3/4. Accordingly, it is preferable to set the position of the opening C in such a portion where the sound pressure increases (the antinode portion of the mode), because it is possible to absorb sound more efficiently. Specifically, when a single opening C is provided, it is preferably provided at 1/4 or 3/4 from one end of the floor. Further, preferably, as shown in FIG. 14 (a), openings C may be provided at two locations of 1/4 and 3/4 from one end. Of course, the set frequency of the resonator connected to the opening C is made to coincide with the frequency in the above mode of the floor.

  When the floor vibrates in a mode having a plurality of nodes as shown in FIG. 14B, there are many antinode portions of the vibration. In this case, when the single opening C is provided, it is preferably provided at the position of the antinode of the vibration (any one of them). In FIG.14 (b), the floor is vibrating in the mode which has a node in the part of 1/4, 1/2, 3/4 from the end. Accordingly, the opening C is preferably provided at any one of 1/8, 3/8, 5/8, and 7/8 from one end.

  More preferably, one opening C is provided in the antinode portion for each wavelength (for example, the opening C is provided in 1/8 and 5/8 portions from one end). More preferably, one opening C is provided in the antinode portion for every half wavelength (ie, as shown in FIG. 14B, 1/8, 3/8, 5/8, 7 / 8 are provided with openings C in all locations).

  In short, it is preferable that at least one or more openings C of the hollow portion targeting the same frequency are located in the length λ of one wavelength at the frequency of the floor. Moreover, it is preferable that the opening C is provided at a position corresponding to an antinode in the vibration mode of the floor.

  As described above, according to the present invention, air vibration generated in the space behind the ceiling can be effectively absorbed by the hollow portion as the resonator, so that air propagation generated by floor vibration can be greatly reduced. At the same time, if the floor is anti-vibrated and supported by the above-described urethane foam 25, rubber, coil springs, etc., air propagation and solid propagation can be reduced simultaneously.

  Furthermore, the length of the resonator is not greatly limited as compared with the configuration in which the opening is provided in the column (the above-mentioned Patent Document 2). Therefore, the sound absorption performance can be exhibited in a wider frequency range.

  In the present invention, since the opening C is not provided on the upper surface side of the floor structure, even if a fire occurs, there is no possibility that the flame propagates through the opening C onto the floor structure. In addition, when fire resistance performance is required for the floor structure, a fireproof film may be provided on the upper surface plate 2 side of the floor structure.

The partial cross section perspective view which shows the 1st example of the floor structure which concerns on one Embodiment of this invention. The partial cross section perspective view which similarly shows the 2nd example. The partial cross section perspective view which shows the 3rd example. The partial cross section perspective view which shows the 4th example. The partial cross section perspective view which shows the mode of vibration measurement experiment. Similarly a schematic cross-sectional view. The graph figure which shows the result of vibration measurement experiment (when the floor is supported by vibration isolation). The graph which shows the result of a vibration measurement experiment (when the floor is not supported by vibration isolation). Explanatory drawing which shows the relationship between an aperture ratio and a sound absorption effect. The bottom view ((1), (2)) which shows the example of arrangement | positioning of the opening part of a floor structure, and the setting frequency of a branch pipe resonator. The bottom view which shows the example of arrangement | positioning of the opening part of a floor structure, and the setting frequency of a branch pipe resonator ((3), (4)). The bottom view ((5)) which shows the example of arrangement of a floor structure opening, and the setting frequency of a branch pipe resonator. The graph which shows the comparison of the sound absorption effect in the examples (1) and (4) of the floor structure. The schematic diagram explaining the preferable example of the position of the opening part in relation to the vibration mode of a floor.

Explanation of symbols

A Floor structure B Hollow part C Opening part D Ceiling back space 1 joist (beam member)
2 Top plate (floor board, face material)
3 Bottom plate 8 Ceiling

Claims (13)

  A floor structure characterized in that at least one hollow part is provided and an opening part is provided for communicating the hollow part with a ceiling space.   The floor structure according to claim 1, wherein a sound absorbing material is installed in the hollow portion.   The floor structure according to claim 1 or 2, comprising a beam member having at least one hollow portion and a face material.   The floor structure according to claim 1 or 2, wherein the upper surface plate and the lower surface plate are joined together by a joining member.   The floor structure according to claim 4, wherein the coupling member is a mold material.   The floor structure according to claim 4, wherein the coupling member is a folded plate.   The floor structure according to any one of claims 4 to 7, wherein the opening is provided in the bottom plate or the coupling member.   The floor structure according to claim 1 or 2, wherein the floor structure has a structure in which a top plate and a mold or a folded plate are combined.   The floor structure according to any one of claims 1 to 8, wherein a partition plate is provided at an arbitrary position in the longitudinal direction of the hollow portion.   The floor structure according to claim 9, wherein an opening smaller than a cross-sectional area of the hollow portion is provided in the partition plate.   The floor structure according to claim 9, wherein a plurality of the hollow portions are provided, and the positions of the partition plates are changed in the respective hollow portions.   At least one or more of the openings communicating with the hollow part constituting the branch pipe resonator for the same frequency are located in the length of one wavelength at the frequency of the floor. The floor structure according to any one of claims 1 to 11.   The floor structure according to claim 12, wherein the opening is formed at a position corresponding to a belly portion of a vibration mode of the floor.

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