JP2023001674A - Ceiling structure and construction method for ceiling structure - Google Patents

Abstract

To effectively reduce a heavy floor impact sound propagated from an upper floor to a lower floor.SOLUTION: A ceiling structure 2 for reducing a floor impact sound of a building comprises a ceiling plate 20 arranged under a floor slab 4 with a gap left and a plurality of vibration control bodies 22 mounted on the ceiling plate 20. The vibration control bodies 22 each comprise a vibration control material 24 including many granules and a box body 26 accommodating the vibration control material 24. The box body 26 includes a bottom plate 28 having a double-layer structure forming an air layer.SELECTED DRAWING: Figure 3

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceiling structure for reducing floor impact noise of a building and a construction method thereof.

In order to suppress the radiation of heavy floor impact sound from the upper floor to the lower floor in a building having multiple floors, there is known a ceiling structure in which a damping body is placed on the ceiling plate to improve the sound absorption performance. (Patent Documents 1 to 3).

The vibration damping body described in Patent Document 1 has a bag whose edge is closed and a vibration damping granular material filled inside the bag, and straddles between adjacent joists at intervals. is placed on the top surface of the ceiling panel.

In the sound absorbing structure described in Patent Literature 2, a first sound absorbing body and a second sound absorbing body each including a granular body and a container containing the granular body are placed on the ceiling. As the container, a bag made of kraft paper or glass cloth that does not hinder the vibration of the granules inside is adopted. The first sound absorbing body and the second sound absorbing body are arranged so as to be individually placed on the ceiling plate and the base material, respectively. This solves the problem that the expected sound absorbing effect cannot be obtained because the load of the granular material is less likely to act on the base material.

The damping body described in Patent Document 3 includes a damping material containing a large number of granular materials, and a bag containing the damping material. The bag contains a tray portion containing the damping material and an upper surface of the tray portion. and a sheet-like cover portion that closes the The damping material is accommodated in the tray part with a gap between it and the cover part.

JP 2019-60147 A JP 2018-13031 A JP 2017-36549 A

However, in the above prior art, the damping material cannot vibrate freely in the bag or container, and the vibration energy propagated from the upper floor cannot be sufficiently damped, so that the heavy floor impact noise is effectively suppressed. There is a possibility that it cannot be reduced effectively.

In view of the above background, it is an object of the present invention to provide a ceiling structure and construction method thereof that can effectively reduce heavy floor impact noise that propagates from upper floors to lower floors.

In order to solve the above problems, one aspect of the present invention is a ceiling structure (2) for reducing floor impact noise of a building, the ceiling being arranged below a floor slab (4) with a gap therebetween. a plate (20) and a plurality of damping bodies (22) placed on the ceiling board, each damping body comprising a number of grains (24); A box (26) for containing the damping material, the box including a bottom plate (28) having a layered structure of at least two layers forming an air layer.

According to this aspect, the damping material vibrates inside the box due to the vibration of the floor impact sound propagating from the floor slab, thereby attenuating the vibration energy. In particular, the bottom plate of the box has at least a two-layer structure that forms an air layer, and rigidity and elasticity are imparted to the bottom plate, so that the damping material bounces easily and the damping material vibrates freely on the bottom plate. become able to. Therefore, the vibration energy can be sufficiently attenuated, and the floor impact noise can be effectively reduced.

In the above aspect, the bottom plate includes an upper plate (36, 46) and a lower plate (38, 48) arranged in parallel with each other at a predetermined interval, and a plurality of plates connecting the upper plate and the lower plate. It is preferable that it is an integral structure having connecting plates (40, 50).

According to this aspect, since the bottom plate is composed of the integrated structure, the box can be easily manufactured and handled.

In the above aspect, the bottom plate is composed of a base plate (52) having a predetermined rigidity and two sheets (54a, 54b) placed on the base plate and forming a plurality of closed cells. and a bubble wrap (54).

According to this aspect, the rigidity of the bottom plate of the box can be secured by the base plate, and the air layer for imparting elasticity to the bottom plate can be formed by the air bubbles of the bubble cushioning material.

Said aspect WHEREIN: It is good for the said box to further contain the partition plate (34) which divides internal space horizontally.

According to this aspect, the floor impact noise can be reduced more effectively.

In the above aspect, the ceiling plate is attached to the lower surface of a plurality of joists (12) arranged to extend horizontally and parallel to each other below the floor slab, and the boxes are adjacent to each other. It is preferable to further include a pair of engaging pieces (42) arranged above the pair of joists so as to be able to engage with the pair of joists from above.

According to this aspect, by engaging the pair of engaging pieces with the pair of ceiling joists, the damping body can be temporarily supported by the ceiling joists. Therefore, the damping body can be easily placed on the ceiling plate.

In order to solve the above problems, another aspect of the present invention is a method of constructing a ceiling structure for reducing floor impact noise of a building, comprising: below a floor slab (4) horizontally and parallel to each other; A step of arranging a plurality of joists (12) so as to extend to (Fig. 5 (A)), a damping material (24) containing a large number of granular bodies, and a box containing the damping material ( 26), wherein the box comprises a bottom plate (28) having a layered structure of at least two layers forming an air layer, and a pair of engaging pieces (42) projecting horizontally in directions separating from each other. providing a plurality of damping bodies (22) comprising a pair of damping bodies (22) disposed between a pair of said joists adjacent to each other and a pair of said joists for a pair of said joists; A step of temporarily supporting the vibration damping body on the pair of joists so that the joint piece is engaged from above and the bottom plate is positioned below the lower surface of the joist (Fig. 5 (B), ( C)), the ceiling plate (20) is pressed against the lower surface of the ceiling joist from below, the bottom plate is brought into contact with the upper surface of the ceiling plate, and the pair of engaging pieces are connected to the pair of joist a step of joining the ceiling board to the ceiling joists in a state of being placed above the ceiling (FIG. 5(D)).

According to this aspect, the bottom plate of the box has at least a two-layer structure forming an air layer, and elasticity is imparted to the bottom plate, so that the damping material can freely vibrate on the bottom plate. As a result, vibration energy can be sufficiently attenuated, and floor impact noise can be effectively reduced. Further, such a vibration damping body can be easily temporarily supported by a pair of ceiling joists by engaging the pair of engaging pieces with the ceiling joist from above. This facilitates the work of placing the damping body on the ceiling plate, and facilitates the construction of the ceiling structure.

In the above aspect, when the damping body is arranged between the pair of joists adjacent to each other, the damping body is tilted and moved above the pair of joists (Fig. 5 ( B1)), after vibrating the damping body above the pair of joists to level the damping material to a uniform thickness inside the box (FIG. 5 (B2)), the damping It is preferable that the material is leveled and lowered to be temporarily supported by the pair of ceiling joists (Fig. 5 (B3)).

According to this aspect, the thickness of the damping material in the box can be easily made uniform, and it is possible to suppress the deterioration of the damping effect of the vibration energy of the damping body due to the unevenness of the damping material. Also, the vibration damping body can be temporarily supported by the ceiling joists in such a state. When the ceiling board is attached to the ceiling joist, the damping material is simply pushed upward by the ceiling board and does not incline.

According to the above aspect, it is possible to provide a ceiling structure and a construction method thereof that can effectively reduce heavy floor impact noise that propagates from the upper floor to the lower floor.

Plan view of the ceiling structure according to the first embodiment II-II sectional view in Fig. 1 III-III enlarged sectional view in Fig. 1 Top view of damping body with lid open Explanatory drawing of the construction procedure of the ceiling structure Enlarged cross-sectional view corresponding to FIG. 3 of the ceiling structure according to the second embodiment Enlarged cross-sectional view corresponding to FIG. 3 of the ceiling structure according to the third embodiment Graph showing the results of comparative experiments on soundproofing performance by box material Graph showing the results of comparative experiments on soundproofing performance depending on the number of layers of bubble cushioning material Graph showing the results of comparative experiments on soundproofing performance depending on the bubble size of bubble cushioning material Graph showing the results of comparative experiments on soundproofing performance depending on the height of the box body Graph showing the results of a comparison experiment of soundproofing performance by the number of internal space divisions of the box

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<<First embodiment>>
1 to 5 show a first embodiment of the invention. As shown in FIGS. 1 and 2, the ceiling structure 2 according to the first embodiment is provided in a building such as a collective housing, and is arranged below a floor slab 4 (FIG. 2) on the upper floor. be. The floor slab 4 is made of reinforced concrete. The floor slab 4 of the upper floor may be a deck plate floor, a cast-in-place concrete floor, a panel floor, or the like arranged on floor beams made of H-shaped steel or the like instead of reinforced concrete.

The ceiling base material 6 is arranged below and close to the floor slab 4 . The ceiling base material 6 includes a pair of runners 10 fixed near the upper ends of walls 8 facing each other on the lower floor and a plurality of joists 12 bridged between the pair of runners. The joists 12 are arranged horizontally and parallel to each other so that adjacent joists 12 are equally spaced.

A pair of runners 10 are positioned near the top of the wall 8, ie, spaced apart from the floor slab 4 of the upper story. A pair of runners 10 are made of lightweight section steel having a channel cross-section, and are arranged parallel and horizontally to each other such that the open surfaces of the channel cross-section face each other. The joist 12 consists of square studs having a rectangular cross section, and is bridged between the pair of runners 10 so as to be perpendicular to each other. Both ends of the joist 12 are supported by the pair of runners 10 by projecting into the channel cross-sectional open surfaces of the pair of runners 10 .

A joist receiver 14 that extends horizontally in a direction orthogonal to the joist 12 and supports the joist 12 is arranged above the intermediate portion of the joist 12 . That is, the joist receivers 14 are arranged parallel to the runners 10 . The joist receiver 14 may be, for example, a square stud with a rectangular cross section or a light-weight shaped steel with a channel cross section, and is suspended below the floor slab 4 by suspension members such as suspension bolts 16 fixed to the floor slab 4. be done. The joist receiver 14 is supported by the suspension bolt 16 via a connection metal fitting 18 attached to the lower end side of the suspension bolt 16 . In another example, the ceiling joist receiver 14 may be directly supported by the hanging bolt 16 .

In the illustrated example, one joist receiver 14 is arranged in the middle portion of the joist 12 in the longitudinal direction. In other examples, depending on the length of the joist 12, a plurality of joist receivers 14 may be provided, or no joist receivers 14 may be provided. When a plurality of ceiling joist receivers 14 are provided, the plurality of ceiling joist receivers 14 are arranged parallel to each other such that the distance between runners 10 and the distance between adjacent ceiling joist receivers 14 are substantially equal. In yet another example, the hanger bolt 16 may directly support the joist 12 without the joist receiver 14, or the hanger bolt 16 may not be provided.

A ceiling plate 20 is attached to the lower surface of the joist 12. - 特許庁The ceiling board 20 is formed of a gypsum board or the like, and is fixed to the lower surfaces of the plurality of ceiling joists 12 using screws. The ceiling plate 20 is an interior material, and a cloth or the like is attached to the lower surface of the ceiling plate 20 to form the ceiling surface of a living room or the like on the lower floor.

A plurality of damping bodies 22 are placed on the ceiling plate 20 . The damping body 22 has a substantially rectangular parallelepiped shape. Assuming that the extending direction of the ceiling joists 12 is the vertical direction and the direction orthogonal to the extending direction of the ceiling joists 12 is the horizontal direction, the vibration damping bodies 22 are aligned in the horizontal direction and are divided by the plurality of ceiling joists 12 in each row. They are arranged in every other space between the joists 12 to be defined. Furthermore, the vibration damping bodies 22 arranged in each row are also aligned in the vertical direction and arranged at equal intervals in the vertical direction.

The arrangement of the damping bodies 22 is not limited to this. In other embodiments, the damping bodies 22 may be staggered such that they are longitudinally offset from each other. Alternatively, the damping bodies 22 may be arranged in all of the spaces between the joists 12 defined by the plurality of joists 12 .

As shown in FIGS. 3 and 4, the damping body 22 includes a damping material 24 and a box 26 that accommodates the damping material 24 . The vibration damping material 24 damps vibration energy by vibrating within the box 26 due to the vibration of the floor impact sound propagating from the floor slab 4, and contains a large number of granular bodies. The damping material 24 has a thickness enough to form a gap in the upper portion of the internal space of the box 26 and is accommodated in the box 26 substantially evenly.

Granules include, but are not limited to, plastic flakes made of plate-shaped deformed resin, plastic pellets made of round-shaped resin, plastic pieces made of cylindrical resin, stem-shaped materials such as charcoal and dried plants. It may be a body or the like. Among these, it is preferable to use plastic flakes as the granules, which showed the greatest floor impact noise reduction effect in the 63 Hz band (1/1 octave band), which is the frequency band that determines general heavy floor impact sound blocking performance.

The box 26 has a hollow structure including a bottom plate 28 , a side plate 30 having a rectangular annular shape in plan view, and a lid plate 32 closing the upper end of the side plate 30 . Inside the box 26, partition plates 34 (34a, 34b) are provided to partition the internal space in the horizontal direction. In the illustrated example, the inside of the box 26 is provided with one vertical partition plate 34a extending in the vertical direction and one horizontal partition plate 34b extending in the horizontal direction. Therefore, the internal space of the box 26 is divided into four.

As shown in FIG. 3, the bottom plate 28 is a resin extrusion, and includes an upper plate 36, a lower plate 38 spaced below the upper plate 36, and the upper plate 36 and the lower plate 38. It has a plurality of connecting plates 40 to be connected. A plurality of connecting plates 40 are arranged in parallel with each other at predetermined intervals. The bottom plate 28 is made of so-called plastic cardboard. Thus, the bottom plate 28 has a two-layer structure in which an air layer is formed between the upper plate 36 and the lower plate 38 . In this embodiment, the plurality of connecting plates 40 extend longitudinally parallel to the joists 12 .

The side plate 30 is made of the same two-layer plate material as the bottom plate 28 . The connecting plates 40 of the side plates 30 are arranged horizontally with a gap in the vertical direction. The lid plate 32 is also made of the same plate material as the bottom plate 28 . In other embodiments, the side plates 30 and lid plate 32 may be formed from a plate material different from the bottom plate 28 .

A pair of engaging pieces 42 are integrally provided on the upper portions of the two plates extending in the vertical direction of the side plate 30 so as to protrude sideways from the side plate 30 . The engaging piece 42 is made of the same two-layer plate material as the bottom plate 28 . The engagement piece 42 may also be formed from a plate material different from the bottom plate 28 in other embodiments. The engaging piece 42 is formed by bending a plate material along three mutually parallel folding lines to have a substantially triangular cross section, and is joined to the side plate 30 to be integrated with the box body 26 . The coupling of the engaging piece 42 to the side plate 30 may be performed by adhesion using an adhesive, adhesive tape, double-sided tape, or the like, welding, or fastening using staples, rivets, or the like. In other embodiments, the engagement piece 42 may be coupled to the cover plate 32 instead of the side plate 30. FIG. Alternatively, the upper portion of the side plate 30 may protrude sideways, and the side plate 30 itself may constitute the engaging piece 42 .

The box 26 is arranged between a pair of joists 12, and the width of the side plate 30 portion is smaller than the gap between the joists 12. - 特許庁On the other hand, the dimension between the outer ends of the pair of engaging pieces 42 is larger than the gap between the joists 12 . Therefore, at least a part of the engaging piece 42 is positioned above the ceiling joist 12, and when there is no ceiling plate 20 below, the engaging piece 42 can engage with the ceiling joist 12 from above.

The ceiling structure 2 is configured as described above. When an impact is applied to the floor slab 4, the floor slab 4 vibrates, and the vibration of the floor impact sound is transmitted through the wall 8 and the air, and further through the suspension bolt 16 if provided, to the floor. It propagates from the slab 4 and excites the joist 12 and the ceiling panel 20 fixed to the joist 12 . The damping body 22 attenuates the vibration energy by vibrating the damping material 24 inside the box 26, and suppresses the vibration of the joist 12 and the ceiling board 20, especially the frequency corresponding to the natural frequency of the damping body 22. to reduce vibration. As a result, the vibrations of the joists 12 and the ceiling board 20 are reduced, and the sound emitted from the ceiling board 20 is reduced.

In particular, in this embodiment, the bottom plate 28 of the box 26 has a two-layer structure forming an air layer, and the bottom plate 28 is imparted with rigidity and elasticity. As a result, the damping material 24 can bounce easily, and the damping material 24 can freely vibrate on the bottom plate 28 . Therefore, vibration energy is sufficiently attenuated, and floor impact noise is effectively reduced.

The bottom plate 28 is an integral structure having an upper plate 36, a lower plate 38, and a plurality of connecting plates 40 arranged parallel to each other with a predetermined interval and connecting the upper plate 36 and the lower plate 38. ing. Since the bottom plate 28 is configured as an integrated structure in this way, the box body 26 can be manufactured and handled easily.

Further, the box 26 includes a pair of engaging pieces 42 arranged above the joists 12 so that they can be engaged with the joists 12 adjacent to each other from above. That is, by engaging the pair of engaging pieces 42 with the pair of joists 12, the vibration damping body 22 can be temporarily supported by the joists 12. As shown in FIG. Therefore, the vibration damping body 22 can be easily placed on the ceiling plate 20 as described in detail below.

A specific construction procedure of the ceiling structure 2 will be described with reference to FIG. Prior to construction of the ceiling structure 2, a plurality of damping bodies 22 having the above configuration are prepared in advance.

At a building site, first, as shown in FIG. 5A, a plurality of joists 12 are arranged so as to extend horizontally and parallel to each other under the floor slab 4 . Next, as shown in FIG. 5B, the damping body 22 is arranged between a pair of joists 12 adjacent to each other, and a pair of engaging pieces 42 are attached to the pair of joists 12. The damping bodies 22 are temporarily supported by the pair of joists 12 so that the bottom plate 28 is positioned below the lower surfaces of the joists 12 by engaging them from above.

At this time, as shown in FIG. 5(B1), the damping body 22 is tilted and moved above the pair of joists 12 . Subsequently, as shown in FIG. 5(B2), the damping member 22 is vibrated above the pair of joists 12 to even out the damping material 24 inside the box 26 to a uniform thickness. Thereafter, as shown in FIG. 5(B3), the damping material 24 is leveled and lowered to be temporarily supported by the pair of joists 12. Then, as shown in FIG.

By arranging the damping bodies 22 in this way, the thickness of the damping material 24 in the box 26 can be easily made uniform, and the vibration energy of the damping bodies 22 can be attenuated by the unevenness of the damping material 24. A decrease in the effect is suppressed. In addition, it is easy to temporarily support the damping body 22 on the joist 12 in such a state. When the ceiling plate 20 is attached to the joist 12, the damping body 22 is simply pushed upward by the ceiling plate 20 and does not incline. not biased.

A plurality of damping bodies 22 are arranged at predetermined positions, and the state shown in FIG. 5(C) is obtained. Thereafter, as shown in FIG. 5(D), the ceiling board 20 is pressed against the lower surface of the ceiling joists 12 from below. As a result, the bottom plate 28 contacts the upper surface of the ceiling plate 20 and the pair of engaging pieces 42 are arranged above the pair of joists 12 . By connecting the ceiling plate 20 to the ceiling joists 12 in this state, the ceiling structure 2 having the above configuration is constructed.

In this way, the bottom plate 28 of the box 26 has at least a two-layer structure forming an air layer, and the elasticity is imparted to the bottom plate 28, so that the damping material 24 can freely vibrate on the bottom plate 28. . As a result, vibration energy can be sufficiently attenuated, and floor impact noise can be effectively reduced. Moreover, such a damping body 22 can be easily temporarily supported by the pair of joists 12 by engaging the pair of engaging pieces 42 with the joist 12 from above. This facilitates the work of placing the damping body 22 on the ceiling plate 20, and facilitates the construction of the ceiling structure 2. As shown in FIG.

<<Second embodiment>>
A second embodiment of the present invention will now be described with reference to FIG. FIG. 6 is an enlarged sectional view corresponding to FIG. 3 of the ceiling structure 2 according to the second embodiment. As shown in FIG. 6, in the ceiling structure 2 of this embodiment, the structure of the box 26 differs from that of the first embodiment. Specifically, the box 26 is made of cardboard (sheet). In this embodiment, the bottom plate 28, the side plates 30, the lid plate 32, and the engaging pieces 42 of the box 26 are made of cardboard. In other embodiments, portions other than the bottom plate 28 may be formed from plate materials other than corrugated cardboard.

The bottom plate 28 comprises a pair of sheets, namely a top sheet 46 and a bottom sheet 48, and a corrugated connecting sheet disposed between and adhered to the top sheet 46 and bottom sheet 48. 50. Thus, the bottom plate 28 has a two-layer structure in which an air layer is formed between the upper sheet 46 and the lower sheet 48 . In other embodiments, the bottom plate 28 may have a layered structure of three or more layers.

Even if the box 26 is configured in this way, the bottom plate 28 has a two-layer structure forming an air layer, so that the bottom plate 28 is provided with rigidity and elasticity. As a result, the damping material 24 can bounce easily, and the damping material 24 can freely vibrate on the bottom plate 28 . Therefore, vibration energy is sufficiently attenuated, and floor impact noise is effectively reduced.

<<Third Embodiment>>
A third embodiment of the present invention will now be described with reference to FIG. FIG. 7 is an enlarged sectional view corresponding to FIG. 3 of the ceiling structure 2 according to the third embodiment. As shown in FIG. 7, also in the ceiling structure 2 of this embodiment, the configuration of the box 26 is different from that of the above embodiment. Specifically, the box body 26 is mainly formed from a base plate 52 that is a solid plate material. The bottom plate 28 of the box 26 includes a base plate 52 , and the side plate 30 , cover plate 32 , partition plate 34 and engagement piece 42 are each formed of the base plate 52 . The base plate 52 may be made of resin, for example, and gives the box 26 a predetermined rigidity. On the other hand, the bottom plate 28 of the box 26 further includes a base plate 52 and a bubble cushioning material 54 placed on the base plate 52 .

The bubble cushioning material 54 is formed by laminating two resin sheets (hereinafter referred to as a first sheet 54a and a second sheet 54b) so as to form a plurality of bubbles. The bubble cushioning material 54 has a two-layer structure in which an air layer is formed by a plurality of bubbles. The first sheet 54a is flat, and the second sheet 54b is uneven to form air bubbles. In this embodiment, the bubble cushioning material 54 is placed on the base plate 52 with the flat first sheet 54a facing upward. Therefore, the entire area between the first sheet 54a and the base plate 52 forms an air layer, and the damping material 24 is accommodated on the first sheet 54a forming the air layer in the entire area of the bottom plate 28. FIG. In other embodiments, the bubble wrap 54 may have a layered structure of three or more layers.

The base plate 52 ensures the rigidity of the box 26 as the bottom plate 28 , and the bubbles of the bubble cushioning material 54 form an air layer for imparting elasticity to the bottom plate 28 . That is, since the bottom plate 28 includes the base plate 52 having a predetermined rigidity and the bubble cushioning material 54 having a layered structure forming an air layer, the bottom plate 28 is provided with rigidity and elasticity. Even if the box 26 is configured in this way, the vibration damping material 24 is easily bounced, and the vibration damping material 24 can freely vibrate on the bottom plate 28 . Therefore, vibration energy is sufficiently attenuated, and floor impact noise is effectively reduced.

Next, the floor impact noise reduction effect of the present invention will be described with reference to FIGS. 8 to 12. FIG. The inventors constructed the ceiling structure 2 using various types of damping members, generated floor impact noise, and measured the level of vibration acceleration that decreases when passing through the ceiling structure 2 . 8 to 12 are graphs showing the results of various experiments conducted by the inventors of the present application. The horizontal axis of the graph indicates the frequency of the floor impact sound, and the vertical axis of the graph indicates the vibration acceleration level difference, that is, the reduction amount of the floor impact sound. The greater the vibration acceleration level difference, the greater the floor impact noise reduction effect (soundproofing performance).

FIG. 8 is a graph showing the result of a comparative experiment on soundproofing performance depending on the material of the box 26. As shown in FIG. In the experiment, a gypsum board was used as the damping member (PB), the damping material 24 was put in a bag (bag), the damping material 24 was put in a thin acrylic case (AC), The vibration damping material 24 in a cardboard box, that is, the vibration damping body 22 (DB box) of the second embodiment, and the vibration damping material 24 in a plastic cardboard box, that is, the vibration damping body of the first embodiment 22 (PB box).

As shown in FIG. 8, gypsum board (PB) has the lowest soundproof performance in the frequency band of 50 to 63 Hz, which indicates heavy floor impact noise. The one in the bag (Bagged) and the one in the acrylic case (AC) showed higher soundproof performance than the gypsum board. On the other hand, the vibration damper 22 (DB box) of the second embodiment and the vibration damper 22 (PB box) of the first embodiment exhibited even higher soundproof performance.

FIG. 9 is a graph showing the results of comparative experiments on soundproofing performance depending on the number of layers of the bubble cushioning material 54. In FIG. In the experiment, as the damping member, the damping material 24 was put in a bag (bag), and the damping material 24 was put in a bag made of a two-layered bubble cushioning material 54 having small bubbles (small particles). 2-layer product), and a bag containing the damping material 24 made of a 3-layer structure bubble cushioning material 54 having small bubbles (small 3-layer product).

As shown in FIG. 9, in the frequency band of 50 to 63 Hz, which indicates heavy floor impact noise, the air bubble cushioning material 54 (small particle 2-layer product) and the air bubble cushioning material 54 (small particle 3-layer product) are higher than those in bags. Demonstrates soundproofing performance.

FIG. 10 is a graph showing the results of a comparative experiment of soundproofing performance depending on the bubble size of the bubble cushioning material 54. As shown in FIG. In the experiment, as the damping member, the damping material 24 was placed in a bag composed of a two-layer structure bubble cushioning material 54 having small bubbles (small grain two-layer product), and the damping material 24 was filled with medium bubbles. A bag made of a two-layered bubble cushioning material 54 (medium grain two-layer product), and a bag made of a two-layered bubble cushioning material 54 with large bubbles The damping material 24 was put in a bag It was carried out using a thing (large grain two-layer product).

As shown in FIG. 10, in the frequency band of 50 to 63 Hz, which indicates heavy floor impact noise, the soundproofing performance of the bubble cushioning material 54 (medium grain two-layer product) is higher than that of the bubble cushioning material 54 (small grain two-layer product). rice field. In the same frequency band, the soundproof performance of the bubble cushioning material 54 (large grain two-layer product) was even higher than that of the bubble cushioning material 54 (medium grain two-layer product).

FIG. 11 is a graph showing the results of comparative experiments on soundproofing performance depending on the height of the box 26. As shown in FIG. In the experiment, a vibration damping body 22 in which a vibration damping material 24 is placed in a corrugated cardboard box similar to the vibration damping body 22 of the second embodiment was used. In the experiment, a cardboard box with a height of 150 mm containing the damping material 24 (DB box H=150), a cardboard box with a height of 125 mm containing the damping material 24 (DB box H=125), A cardboard box with a height of 100 mm containing the damping material 24 (DB box H = 100) and a cardboard box with a height of 70 mm containing the damping material 24 (DB box H = 70) were used. rice field.

In the damping body 22 that attenuates the vibration energy by vibrating the damping material 24, the damping material 24 needs to vibrate freely. Therefore, it is necessary to provide a space above the damping material 24 so that the damping material 24 does not collide with the cover plate 32, and if the height of the box 26 is low, the soundproofing performance is lowered.

As shown in FIG. 11, the DB box H=70 exhibits high soundproofing performance in the frequency band of 50 to 63Hz, which indicates heavy floor impact noise. ing. On the other hand, even if the height of the DB box H=150 or the DB box H=125 is increased, no improvement in the soundproofing performance is observed compared to the DB box H=100. This means that simply increasing the space does not contribute to the improvement of the soundproofing performance. Therefore, the height of the box 26 may be any size that can secure a space that allows the damping material 24 to vibrate freely, such as a corrugated cardboard box with a height of 100 mm.

FIG. 12 is a graph showing the result of a comparison experiment of soundproofing performance depending on the number of internal space divisions of the box 26. In FIG. In the experiment, a vibration damping body 22 in which a vibration damping material 24 is placed in a plastic corrugated cardboard box similar to the vibration damping body 22 of the first embodiment was used. In the experiment, the internal space of the box 26 was not divided (no division), the internal space of the box 26 was divided into 8, 9, 6, and 4 divisions. I used what I had.

As shown in FIG. 12, in the frequency band of 50 to 63 Hz indicating heavy floor impact sound, the non-divided soundproofing performance is the lowest. Others showed remarkably high soundproofing performance compared to no division, but there was no significant difference due to the number of divisions.

From the above, it can be seen that the floor impact noise can be more effectively reduced by including the partition plate 34 that horizontally divides the internal space of the box 26 .

Although the specific embodiments have been described above, the present invention is not limited to the above-described embodiments and modifications, and can be widely modified. For example, the specific configuration, arrangement, quantity, angle, material, etc. of each member and portion can be changed as appropriate within the scope of the present invention. On the other hand, not all of the components shown in the above embodiments are essential, and can be selected as appropriate.

2: Ceiling structure 4: Floor slab 12: Ceiling 20: Ceiling plate 22: Damping body 24: Damping material 26: Box 28: Bottom plate 34: Partition plate 34a: Vertical partition plate 34b: Horizontal partition plate 42: Engagement Joint piece 46: Upper sheet (upper plate)
48: lower sheet (lower plate)
50: Connection sheet (connection plate)
52: base plate 54: bubble cushioning material 54a: first sheet 54b: second sheet

Claims (7)

A ceiling structure for reducing floor impact noise of a building,
a ceiling plate arranged with a gap below the floor slab;
A plurality of damping bodies placed on the ceiling plate,
Each of the damping bodies includes a damping material containing a large number of granules and a box housing the damping material, and the box has a layered structure of at least two layers forming an air layer. Ceiling structure including bottom plate. 2. The bottom plate according to claim 1, wherein the bottom plate is an integral structure having an upper plate, a lower plate, and a plurality of connecting plates arranged in parallel with each other at predetermined intervals and connecting the upper plate and the lower plate. ceiling structure. 2. The bottom plate according to claim 1, wherein the base plate comprises a base plate having a predetermined rigidity and a bubble cushioning material consisting of two sheets placed on the base plate to form a plurality of closed cells. ceiling structure. 4. The ceiling structure according to any one of claims 1 to 3, wherein the box further includes a partition plate that horizontally divides the internal space. The ceiling board is attached to the lower surface of a plurality of ceiling joists arranged to extend horizontally and parallel to each other below the floor slab,
Any one of claims 1 to 4, wherein the box further includes a pair of engaging pieces arranged above the joists so that they can be engaged with the pair of joists adjacent to each other from above. or the ceiling structure according to 1. A method for constructing a ceiling structure for reducing floor impact noise of a building, comprising:
arranging a plurality of joists to extend horizontally and parallel to each other under the floor slab;
Equipped with a damping material containing a large number of granules and a box housing the damping material, the box having a layer structure of at least two layers forming an air layer and a bottom plate in a direction away from each other preparing a plurality of damping bodies each including a pair of horizontally projecting engagement pieces;
The damping body is arranged between the pair of joists adjacent to each other, the pair of engaging pieces are engaged with the pair of joists from above, and the bottom plate is positioned between the joists. a step of temporarily supporting the vibration damping body on the pair of joists so as to be positioned below the lower surface;
A ceiling plate is pressed against the lower surface of the ceiling joist from below, the bottom plate is in contact with the upper surface of the ceiling plate, and the pair of engaging pieces are arranged above the pair of ceiling joists. and connecting a ceiling board to the ceiling joists. When arranging the damping body between the pair of joists close to each other, the damping body is tilted and moved above the pair of joists, and above the pair of joists After vibrating the damping body and leveling the damping material to a uniform thickness inside the box, the damping material is horizontally lowered and temporarily supported by the pair of joists. Item 7. A method for constructing a ceiling structure according to Item 6.

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