JP7692575B2 - floating floor structure - Google Patents

Description

The present invention relates to a floating floor structure that includes a buffer body disposed on a floor slab and a floating floor section disposed on the buffer body.

Conventionally, a floating floor structure has been adopted as a noise countermeasure in mid- to high-rise concrete apartment buildings, in which a buffer is placed on a floor slab such as a concrete slab, and a concrete floating floor is placed on this buffer. The floating floor structure described in Patent Document 1 uses inorganic fiberboard such as glass wool or rock wool as a buffer placed between the floor slab and the concrete floating floor.

However, when inorganic fiberboards such as glass wool absorb moisture, the vibration-proofing and sound-proofing performance of the floating floor structure deteriorates, so a waterproof layer must be laid before pouring concrete on-site. This increases the number of steps required to construct the floating floor structure, which results in a longer construction period.

As a result, it has been proposed to use synthetic resin foam as the material for the main body of the cushioning body, as in the floating floor structure described in Patent Document 2. Since synthetic resin foam has low water absorption, the vibration-proofing and sound-proofing performance of the floating floor structure will not deteriorate even in places where water absorption is highly likely.

Furthermore, in the floating floor structure described in Patent Document 2, the buffer body has a plurality of storage holes formed penetrating the thickness direction. A water-resistant elastic body that has less creep deformation than the buffer body (synthetic resin foam) is disposed in each storage hole of the buffer body. Each elastic body is configured to support the load of the floating floor section as the buffer body undergoes compressive deformation due to the load of the floating floor section. Therefore, the sinking of the floating floor section due to compressive deformation of the buffer body can be kept within an acceptable range.

Japanese Patent Application Publication No. 3-100262 JP 2001-200629 A

However, relatively expensive materials such as urethane elastomers are used as the elastic body to improve vibration isolation performance while ensuring sufficient load-bearing performance against the live load of the floating floor section. Therefore, there has been a demand for the emergence of a floating floor structure that can improve vibration isolation performance while ensuring sufficient load-bearing performance, while reducing construction costs by reducing the amount of relatively expensive elastic body used.

Therefore, one aspect of the present invention aims to reduce the construction costs of a floating floor structure while adequately ensuring the load-bearing performance of the floating floor structure and improving the vibration-proofing and sound-proofing performance of the floating floor structure.

The inventors of the present application, through repeated trial and error, have discovered that when a thickness adjusting material is arranged so as to vertically overlap with an elastic body within a housing hole of a cushioning body made of a polyolefin foam, it is possible to reduce costs and improve the vibration-proofing and sound-insulating performance of a floating floor structure while sufficiently ensuring the load-bearing performance of the floating floor structure by appropriately setting the dynamic spring constants of the cushioning body and the elastic body, and have completed the present invention. Here, appropriately setting the dynamic spring constants of the cushioning body and the elastic body means setting the dynamic spring constant of the cushioning body to 10 x ¹⁰⁶ N/m3 or ^less and setting the dynamic spring constant of the elastic body to 7 x ¹⁰⁶ N/m3 or ^less (see Examples described later).

A floating floor structure according to one embodiment of the present invention comprises a buffer body disposed on a floor slab and a floating floor section disposed on the buffer body, the buffer body being made of polyolefin resin foam and comprising a buffer body main body having an accommodation hole formed therethrough in the vertical direction, and a load support material disposed within the accommodation hole of the buffer body main body and configured to support the load of the floating floor section as the buffer body main body undergoes compressive deformation due to the load of the floating floor section, the load support material comprising an elastic body and a thickness adjustment material arranged to overlap the elastic body in the vertical direction, the thickness adjustment material being more rigid than the buffer body main body and the elastic body and adjusting the thickness of the load support material, the dynamic spring constant of the buffer body being 10 x ¹⁰⁶ N/ ^m3 or less, and the dynamic spring constant of the elastic body being 7 x ¹⁰⁶ N/m3 or ^less .

In the floating floor structure, the dynamic spring constant of the elastic body may be 1×10 ⁶ N/m ³ or more.

In the floating floor structure, the ratio of the volume of the elastic body to the volume of each load support may be 20% to 60%.

In the floating floor structure, the dynamic spring constant of the buffer body may be 2×10 ⁶ N/m ³ or more.

In the floating floor structure, the ratio of the total area of the upper surfaces of all the load-bearing members to the total area of the upper surfaces of the buffer body may be between 1% and 3%.

In the floating floor structure, the elastic body may be made of high density polyurethane foam, and the density of the elastic body may be 300 kg/m ³ to 800 kg/m ³ .

In the floating floor structure, the thickness adjustment material may be made of at least one material selected from the group consisting of concrete, metal, wood, and synthetic resin.

In the floating floor structure, the polyolefin resin foam that is the material of the buffer body may have a bulk density of 12 kg/m ³ to 20 kg/m ³ , and the polyolefin resin foam may have a closed cell rate of 80% or more.

According to one aspect of the present invention, it is possible to reduce the construction costs of a floating floor structure, while ensuring sufficient load-bearing performance of the floating floor structure and improving the vibration-proofing and sound-proofing performance of the floating floor structure.

FIG. 2 is a schematic cross-sectional view of the floating floor structure according to the present embodiment. FIG. 11 is a schematic cross-sectional view of a floating floor structure according to another aspect of this embodiment. FIG. 11 is a schematic cross-sectional view of a floating floor structure according to another aspect of this embodiment. FIG. 11 is a schematic cross-sectional view of a floating floor structure according to another aspect of this embodiment. FIG. 11 is a schematic cross-sectional view of a floating floor structure according to another aspect of this embodiment.

Hereinafter, this embodiment will be described with reference to Figs. 1 to 5. Fig. 1 is a schematic cross-sectional view of a floating floor structure according to this embodiment. Figs. 2 to 5 are schematic cross-sectional views of floating floor structures according to other aspects of this embodiment. In this specification, unless otherwise specified, "A to B" indicating a numerical range means "A or more (including A and larger than A)" or "B or less (including B and smaller than B)."

(Outline of the floating floor structure 10)
As shown in Figure 1, the floating floor structure 10 according to this embodiment includes a buffer body 14 disposed on a floor slab 12, such as a concrete slab, and a floating floor section 16 made of concrete disposed on the buffer body 14. The specific configuration of the floating floor structure 10 is as follows.

(Buffer body 18)
As shown in FIG. 1, the buffer 14 has a buffer body 18 made of a polyolefin resin foam. The buffer body 18 has a plurality of rectangular accommodation holes 18h formed in the vertical direction (thickness direction) in a plan view, and the plurality of accommodation holes 18h of the buffer body 18 are evenly arranged. The plan view shape of each accommodation hole 18h of the buffer body 18 may be a shape other than a rectangle, such as a circle. In addition, a vibration insulating portion 18f is formed to rise from the outer edge of the buffer body 18. The buffer body 18 functions as a formwork for constructing the floating floor portion 16 by pouring concrete.

(Load support material 20, elastic body 22, thickness adjustment material 24)
1, the buffer body 14 has load support materials 20 filled and arranged in each accommodation hole 18h of the buffer body main body 18, and each load support material 20 supports the load of the floating floor portion 16, including the weight of the floating floor portion 16. Each load support material 20 is configured to support the load of the floating floor portion 16 as the buffer body main body 18 compresses and deforms due to the load of the floating floor portion 16.

Each load support 20 has a water-resistant elastic body 22 that has less creep deformation than the buffer body 18 (polyolefin resin foam). The elastic body 22 is formed in a block or plate shape, and the planar shape of the elastic body 22 is the same as the planar shape of the accommodation hole 18h of the buffer body 18.

Each load support member 20 has a thickness adjustment member 24 that adjusts its thickness, and the thickness adjustment member 24 is arranged so as to overlap vertically below the elastic body 22. The thickness adjustment member 24 is formed in a block or plate shape, and the planar shape of the thickness adjustment member 24 is the same as the planar shape of the accommodation hole 18h of the buffer body main body 18. The thickness adjustment member 24 is configured to be more rigid (higher rigidity) than the buffer body main body 18 and the elastic body 22.

The thickness of each load support member 20 is the same as the thickness of the buffer body 22 excluding the vibration insulation portion 18f. Note that the thickness of each load support member 20 may be thicker than the thickness of the buffer body 22 excluding the vibration insulation portion 18f.

More specifically, the buffer 14 is configured as an assembly of a plurality of panels of the buffer body 18 (for example, panels with an area of 1 ^m2 ). One accommodation hole 18h is provided for each panel of the buffer body 18. The accommodation hole 18h is provided in the center of the buffer body 18. The load support material 20 is filled into the accommodation hole 18h. The number of the accommodation holes 18h and the load support materials 20 is not particularly limited. However, from the viewpoint of cost, it is preferable that the number of the accommodation holes 18h and the load support materials 20 is small.

(Other aspects of the load support 20)
Instead of arranging the thickness adjusting material 24 so as to overlap vertically below the elastic body 22, as shown in FIG. 2, the thickness adjusting material 24 may be arranged so as to overlap vertically above the elastic body 22. Also, as shown in FIG. 3, each load support material 20 may have two elastic bodies 22, and the thickness adjusting material 24 may be arranged so as to overlap vertically on the two elastic bodies 22 in a state in which it is sandwiched between the two elastic bodies 22. As shown in FIG. 4, each load support material 20 may have two thickness adjusting materials 24, and the two thickness adjusting materials 24 may be arranged so as to overlap vertically on the elastic body 22 in a state in which they sandwich the elastic body 22. As shown in FIG. 5, each load support material 20 may have a plurality of elastic bodies 22 and a plurality of thickness adjusting materials 24, and the elastic bodies 22 and the thickness adjusting materials 24 may be arranged so as to overlap vertically alternately. Note that, since the elastic body is made of a relatively expensive material, it is preferable that the thickness of the elastic body 22 is thin from the viewpoint of cost.

(Area ratio of load support material 20)
As shown in FIG. 1, the ratio of the total area of the upper surfaces of all the load support members 20 to the total area of the upper surface of the buffer body 14 excluding the vibration insulating portion 18f (hereinafter referred to as the area ratio of the load support members 20) is 1% to 3%, preferably 1% to 2.5%, and more preferably 1% to 2%. In other words, the ratio of the total area of the openings of all the accommodation holes 18h to the total area of the upper surface of the buffer body 14 excluding the vibration insulating portion 18f is 1% or more and 3% or less. The reason why the area ratio of the load support members 20 is set to 1% or more is that if the area ratio of the load support members 20 is less than 1%, it is difficult for the multiple load support members 20 to sufficiently support the load of the floating floor portion 16. The reason why the area ratio of the load support members 20 is set to 3% or less is that if the area ratio of the load support members 20 exceeds 3%, the occupancy rate of the thickness adjustment member 24, which is a rigid member, in the buffer body 14 increases, and the vibration-proofing performance of the buffer body 14 tends to decrease.

Next, we will explain the material and physical properties of the cushioning body 14.

(Manufacture of the material for the cushioning body 18)
The polyolefin-based resin foam, which is the material of the shock absorber body 18 shown in Fig. 1, may be produced by either a bead foaming method or an extrusion foaming method. In terms of production costs, the polyolefin-based resin foam is preferably produced by the bead foaming method.

A dense and smooth skin layer is formed on the entire surface of the polyolefin resin foam produced by the bead expansion method. Therefore, the polyolefin resin foam produced by the bead expansion method produces less debris, and the strength of the cushion body 18 is improved.

When producing a polyolefin resin foam by the bead expansion method, first, expandable particles made by expanding polyolefin resin into beads are filled into a molding die. Next, the molding die is heated to a specified temperature and then cooled. The molding die is then opened and the polyolefin resin foam is removed.

When producing polyolefin resin foam by extrusion foaming, first, a polyolefin resin composition to which a cell regulator and flame retardant have been added as necessary is fed to an extruder, where it is heated and melted. Next, a foaming agent is injected into the molten polyolefin resin composition, which is then further heated and melted while being kneaded to produce a homogeneous flowing composition. The homogeneous flowing composition is then extruded from a die orifice at the tip of a flat die, and passed through a shaping device called a guider to extract an olefin resin foam.

(Material Form of Cushioning Body 18)
The polyolefin-based resin foam that is the material of the buffer body 18 may have a skin or may be sliced. The polyolefin-based resin foam may be laminated with an adhesive, an adhesive tape, etc. The shape of the polyolefin-based resin foam is not particularly limited, but a plate or block shape is preferable because it is easy to process.

(Polyolefin resin constituting the material of the shock absorber body 18)
Specific examples of polyolefin-based resins constituting the polyolefin-based resin foam that is the material of the buffer body 18 include polyethylene-based resins whose main component is ethylene, such as high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene, and polypropylene-based resins whose main component is propylene. These polyolefin-based resins may be used alone or in combination of two or more. Among these polyolefin-based resins, polyethylene-based resins whose main component is polyethylene are preferred in that the buffer body 14 can fully exhibit the desired vibration-proofing performance.

Specific examples of monomers for polyolefin resins (hereinafter sometimes referred to as olefin monomers) include α-olefins having 2 to 12 carbon atoms, such as ethylene, propylene, butene-1, isobutene, pentene-1, 3-methyl-butene-1, hexene-1, 4-methyl-pentene-1, 3,4-dimethyl-butene-1, heptene-1, 3-methyl-hexene-1, octene-1, and decene-1. These may be used alone or in combination of two or more.

Other monomers copolymerizable with the olefin monomers include, for example, cyclic olefins such as cyclopentene, norbornene, and 1,4,5,8-dimethano-1,2,3,4,4a,8,8a,6-octahydronaphthalene, and dienes such as 5-methylene-2-norbornene, 5-ethylidene-2-norbornene, 1,4-hexadiene, methyl-1,4-hexadiene, and 7-methyl-1,6-octadiene. These may be used alone or in combination of two or more.

(Additives for the material of the shock absorber body 18)
The polyolefin resin foam, which is the material of the buffer body 18, may contain various additives such as antistatic agents, cell regulators, flame retardants, flame retardant assistants, and fillers, as necessary. In particular, in order to improve the creep characteristics of the buffer body 18, it is preferable that the polyolefin resin foam contains an inorganic filler. Examples of inorganic fillers include calcium carbonate, talc, silica, clay, wollastonite, potassium titanate, alumina, mica, and glass balloons. The content of the inorganic filler can be appropriately set according to the desired creep characteristics.

(Physical properties of the buffer body 18, etc.)
The dynamic spring constant of the buffer body 18 (polyolefin resin foam) is 2×10 ⁶ N/m ³ to 10×10 ⁶ N/m ³ , preferably 5×10 ⁶ N/m ³ to 10×10 ⁶ N/m ³ , and more preferably 7×10 ⁶ N/m ³ to 9×10 ⁶ N/m ³ . The reason why the dynamic spring constant of the buffer body 18 is set to 2×10 ⁶ N/m ³ or more is that if the dynamic spring constant of the buffer body 18 is less than 2×10 ⁶ N/m ³ , it becomes difficult for the buffer body 14 to sufficiently support the load of the floating floor section 16. The dynamic spring constant of the buffer body 18 is set to 10 x 10 ⁶ N/m ³ or less because if the dynamic spring constant of the buffer body 18 exceeds 10 x 10 ⁶ N/m ³ , it becomes difficult to suppress the vibrations transmitted between the floor slab 12 and the floating floor portion 16.

The static spring constant of the buffer body 18 is 6×10 ⁶ N/m ³ to 8×10 ⁶ N/m ³ , preferably 6.5×10 ⁶ N/m ³ to 8×10 ⁶ N/m ³ , and more preferably 7×10 ⁶ N/m ³ to 8×10 ⁶ N/m ^3. The dynamic spring constant of the buffer body 18 is set to 6×10 ⁶ N/m ³ or more because if the static spring constant of the buffer body 18 is less than 6×10 ⁶ N/m ³ , the buffer body 18 will be too soft, making it difficult for the buffer body 18 to adequately support the load of the floating floor section 16. The static spring constant of the buffer body 18 is set to 8×10 ⁶ N/m ³ or less because if the static spring constant of the buffer body 18 exceeds 8×10 ⁶ N/m ³ , the buffer body 18 becomes too hard, and the vibration-damping performance of the buffer 14 (buffer body 18) tends to decrease.

The thickness of the buffer body 18 is 25 mm to 200 mm, preferably 50 mm to 100 mm. The reason why the thickness of the buffer body 18 is set to 25 mm or more is that if the thickness of the buffer body 18 is less than 25 mm, the vibration-proofing performance of the buffer 14 tends to decrease. The reason why the thickness of the buffer body 18 is set to less than 200 mm is that if the thickness of the buffer body 18 is 200 mm or more, the vibration-proofing performance of the buffer 14 tends to improve, but the cost of the buffer 14 tends to increase.

The bulk density of the polyolefin-based resin foam, which is the material of the buffer body 18, is 12 kg/m ³ to 20 kg/m ³ , preferably 13 kg/m ³ to 18 kg/m ³ , and more preferably 14 kg/m ³ to 16 kg/m ³ . The reason why the bulk density of the polyolefin-based resin foam is set to 12 kg/m ³ or more is that if the bulk density of the polyolefin-based resin foam is less than 20 kg/m ³ , the buffer body 18 cannot ensure sufficient strength to support the load of the floating floor section 16. The reason why the bulk density of the polyolefin-based resin foam is set to 20 kg/m ³ or less is that if the bulk density of the polyolefin-based resin foam exceeds 20 kg/m ³ , the buffer body 18 becomes too hard, and the dynamic spring constant of the buffer body 18 exceeds 10×10 ⁶ N/m ³ , making it difficult for the buffer 14 to exhibit the desired vibration-proofing and sound-proofing performance.

The closed cell ratio of the polyolefin resin foam that is the material of the buffer body 18 is not particularly limited, but is preferably 80% or more. This is because, when the closed cell ratio of the polyolefin resin foam is 80% or more, the dynamic spring constant of the buffer body 18 can be easily set to 2×10 ⁶ N/m ³ to 10×10 ⁶ N/m ³ .

(Material and properties of elastic body 22)
The elastic body 22 is made of high density polyurethane foam, particularly ether-based high density polyurethane foam. By using high density polyurethane foam as the material for the elastic body 22, it is possible to achieve both vibration-proofing performance and load-bearing performance of the buffer body 14. In particular, by using high density ether-based polyurethane foam as the material for the elastic body 22, it is possible to improve the water resistance of the buffer body 14.

The ratio of the volume of the elastic body 22 to the volume of each load support member 20 (hereinafter referred to as the volume ratio of the elastic body 22) is 20% to 60%, preferably 25% to 50%, and more preferably 30% to 50%. The volume ratio of the elastic body 22 is set to 20% or more because if the volume ratio of the elastic body 22 is less than 20%, the occupancy rate of the thickness adjustment material 24, which is a rigid member, in the buffer body 14 increases, and the vibration-proofing performance of the buffer body 14 tends to decrease. The volume ratio of the elastic body 22 is set to 60% or less because if the volume ratio of the elastic body 22 exceeds 60%, the amount of distortion of the elastic body 22 with respect to the load of the floating floor section 16 increases, the buffer body main body 18 collapses, and the vibration-proofing performance of the buffer body 14 tends to decrease. If the volume ratio of the elastic body 22 exceeds 60%, the amount of the elastic body 22 used increases, and the construction cost of the floating floor structure 10 tends to increase.

The dynamic spring constant of the elastic body 22 is 1×10 ⁶ N/m ³ to 7×10 ⁶ N/m ³ , preferably 1.2×10 ⁶ N/m ³ to 5×10 ⁶ N/m ³ , and more preferably 1.5×10 ⁶ N/m ³ to 3×10 ⁶ N/m ^3. By setting the dynamic spring constant of the elastic body 22 within such a numerical range, vibrations transmitted between the floor slab 12 and the floating floor portion 16 are suppressed, and the buffer body 14 can exhibit the desired vibration isolation performance.

The static spring constant of the elastic body 22 is 15×10 ⁶ N/m ³ to 200×10 ⁶ N/m ³ or less, preferably 50×10 ⁶ N/m ³ to 150×10 ⁶ N/m ³ , and more preferably 75×10 ⁶ N/m ³ to 100×10 ⁶ N/m ^3. The static spring constant of the elastic body 22 is set to 15×10 ⁶ N/m ³ or more because, if the static spring constant of the elastic body 22 is less than 15×10 ⁶ N/m ³ , the elastic body 22 will not be able to ensure sufficient hardness, the elastic body 22 will not be able to adequately support the load of the floating floor section 16, the buffer body main body 18 will be crushed, and it will be difficult for the buffer body 14 to exhibit the desired vibration-proofing performance. If the static spring constant of the elastic body 22 is less than 15×10 ⁶ N/m ³ , it will be difficult to construct the floating floor structure 10 as designed. The static spring constant of the elastic body 22 is set to 200×10 ⁶ N/m ³ or less because if the static spring constant of the elastic body 22 exceeds 200×10 ⁶ N/m ³ , although the elastic body 22 can adequately support the load of the floating floor section 16, the elastic body 22 becomes too hard and the vibration isolation performance of the buffer body main body 18 tends to decrease.

The density of the elastic body 22 is 300 kg/m ³ to 800 kg/m ³ , preferably 300 kg/m ³ to 750 kg/m ^3. The reason why the density of the elastic body 22 is set to 300 kg/m ³ or more is that if the density of the elastic body 22 is less than 300 kg/m ³ , the elastic body 22 cannot ensure sufficient hardness to support the load of the floating floor section 16. The reason why the density of the elastic body 22 is set to 800 kg/m ³ or less is that if the density of the elastic body 22 exceeds 800 kg/m ³ , the elastic body 22 becomes too hard, making it difficult for the buffer body 14 to exhibit the desired vibration-proofing and sound-proofing performance.

(Material of thickness adjusting material 24)
The material of the thickness adjusting material 24 may be a material that is rigid (highly rigid) enough not to be deformed by the load of the floating floor section 16, and the thickness adjusting material 24 is made of at least one material selected from the group consisting of concrete, metal, wood, and synthetic resin. Examples of the synthetic resin used as the material of the thickness adjusting material 24 include polyvinyl chloride, polyethylene, polypropylene, polyester, polystyrene, polyamide, and ABS resin. These resins may contain reinforcing materials such as fillers and additives such as antioxidants. The synthetic resin used as the material of the thickness adjusting material 24 does not have to be solid, and may be foamed at a low foaming ratio, for example, as long as it can maintain its rigidity.

(Characteristics of the floating floor structure 10)
When the thickness of the buffer body 14 excluding the vibration insulating portion 18f is 50 mm, the natural frequency of the buffer body 14 is preferably less than 30 Hz. This is because if the natural frequency of the buffer body 14 is 30 Hz or more, it becomes difficult for the buffer body 14 to fully exhibit the desired vibration isolation performance.

It is preferable that the amount of distortion (sinking) of the buffer 14 due to the load on the floating floor section 16 is less than 10% of the initial thickness of the buffer 14. If the amount of distortion of the buffer 14 is 10% or more of the initial thickness of the buffer 14, it becomes difficult for the buffer 14 to exert the desired vibration-proofing performance while keeping the sinking of the floating floor structure 10 within an acceptable range.

(Action and Effect)
Next, the effects of this embodiment will be described.

As described above, the buffer body 18 is made of a polyolefin resin foam, and the thickness adjusting material 24 is disposed in each accommodation hole 18h of the buffer body 18 so as to vertically overlap the elastic body 22. The dynamic spring constant of the buffer body 18 is 10×10 ⁶ N/m ³ or less, and the dynamic spring constant of the elastic body 22 is 7×10 ⁶ N/m ³ or less. Therefore, the load-bearing performance of the buffer body 14 (floating floor structure 10) can be sufficiently ensured, while the vibration-proofing performance and sound-proofing performance of the buffer body 14 can be improved.

In addition, because the volume ratio of the elastic body 22 is 20% to 60%, the amount of elastic body 22 used can be reduced while preventing a decrease in the vibration-proofing performance of the buffer body 14, thereby reducing the construction costs of the floating floor structure 10.

In other words, according to this embodiment, it is possible to reduce the construction costs of the floating floor structure 10, while sufficiently ensuring the load-bearing performance of the floating floor structure 10, and improve the vibration-proofing and sound-proofing performance of the floating floor structure 10.

In particular, since the static spring constant of the buffer body 18 is smaller than the static spring constant of the elastic body 22, the buffer body 18 can support the load of the floating floor section 16 without impeding the vibration-proofing action of the load support material 20. As a result, according to this embodiment, the load-bearing performance and vibration-proofing performance of the floating floor structure 10 can be further improved.

The following describes examples and comparative examples of the present invention. Note that the floating floor structure of the present invention is not limited to the descriptions of the examples and comparative examples.

(Examples 1 to 5)
Test specimens 1 ^{to 4} were produced, each of which was equipped with a shock absorber body (length 1 m x width 1 m x thickness 50 mm) made of a polyethylene resin foam with a bulk density of 18.4 kg/m3 (Vibran E-60 manufactured by Tokyo V-Tech Co., Ltd., closed cell ratio 92%) and a load support material filled and arranged in the accommodation hole in the center of the shock absorber body. Test specimens 1 to 4 are test specimens simulating the floating floor structure 10 according to this embodiment (see FIG. 1), and are test specimens of Examples 1 to 4. The dimensions of the load support material in test specimens 1 to 4 are the dimensions in Examples 1 to 4 shown in Table 1. The elastic body of the load support material in test specimens 1 to 4 is made of a polyurethane resin elastomer (Cell Damper BF-500 manufactured by Inoac Corporation). The thickness adjustment material of the load support material in test specimens 1 to 4 is made of synthetic wood made of polystyrene resin with an expansion ratio of 3 times.

A test specimen ⁵ was produced, which includes a buffer body (length 1 m x width 1 m x thickness 50 mm) made of a polyethylene resin foam having a bulk density of 12.5 kg/m3 (Vibran E-75 manufactured by Tokyo V-Tech Co., Ltd., closed cell ratio 88%) and a load support material filled and arranged in a receiving hole in the center of the buffer body. The test specimen 5 is a test specimen simulating the floating floor structure 10 according to the present embodiment, and is a test specimen of Example 5. The dimensions of the load support material in the test specimen 5 are the dimensions in the case of Example 5 shown in Table 1. The elastic body of the load support material of the test specimen 5 is made of a polyurethane resin elastomer (Cell Damper BF-700 manufactured by Inoac Corporation). The thickness adjustment material of the load support material of the test specimen 5 is made of synthetic wood made of polystyrene resin with an expansion ratio of 3 times.

From Table 1, the area ratio of the load support material in specimens 1, 2, and 5 is (100 mm x 100 mm) / (1000 mm x 1000 mm) x 100 = 1.00%. Also, the area ratio of the load support material in specimens 3 and 4 is (141 mm x 141 mm) / (1000 mm x 1000 mm) x 100 = 2.00%.

(Comparative Examples 1 to 6)
Comparative Example 1: Comparative specimen 1 was produced in the same manner as in Example 1, except that an elastic body measuring 100 mm in length x 100 mm in width x 50 mm in thickness was used as the load-bearing material, and no thickness-adjusting material was used.

Comparative Example 2: Comparative specimen 2 was produced in the same manner as Comparative Example 1, except that an elastic body measuring 70.7 mm in length, 70.7 mm in width, and 50 mm in thickness was used as the load-bearing material.

Comparative Example 3: Comparative specimen 3 was fabricated in the same manner as in Example 1, except that a load-bearing member was made of an elastic body measuring 70.7 mm in length, 70.7 mm in width, and 25 mm in thickness, and a thickness-adjusting material measuring 70.7 mm in length, 70.7 mm in width, and 25 mm in thickness.

Comparative Example 4: Comparative specimen 4 was produced in the same manner as in Example 1, except that a thickness-adjusting material measuring 100 mm in length, 100 mm in width, and 50 mm in thickness was used as the load-bearing material, and no elastic body was used.

Comparative Example 5: Comparative specimen ⁵ was produced in the same manner as in Example 1, except that a cushioning body (length 1 m × width 1 m × thickness 50 mm) made of a polyethylene resin foam having a bulk density of 24.2 kg/m3 (Vibran E-38 manufactured by Tokyo V-Tech, closed cell ratio 95%) was used.

Comparative Example 6: A comparative specimen ⁶ was produced, which had a buffer body (length 1 m x width 1 m x thickness 50 mm) made of a polyethylene resin foam with a bulk density of 12.5 kg/m3 (Vibran E-75 manufactured by Tokyo V-Tech, closed cell ratio 88%) and a load support material filled in the accommodation hole in the center of the buffer body. In the comparative specimen 6, an elastic body with a length of 70.7 mm x width of 70.7 mm x thickness of 50 mm was used as the load support material, and no thickness adjustment material was used. The elastic body of the load support material of the comparative specimen 6 was made of a polyurethane resin elastomer (Cell Damper BF-700 manufactured by Inoac Corporation).

From Table 1, the area ratio of the load support material in comparative specimens 1, 4, and 5 is (100 mm x 100 mm) / (1000 mm x 1000 mm) x 100 = 1.00%. Also, the area ratio of the load support material in comparative specimens 2, 3, and 6 is (70.7 mm x 70.7 mm) / (1000 mm x 1000 mm) x 100 = 0.50%.

(Dimensions of test specimen and comparison specimen, etc.)
The length and width of the buffer body and the like of the test specimens 1 to 5 and the comparative test specimens 1 to 6 were measured using a tape measure. The thickness of the buffer body and the like of the test specimens 1 to 5 and the comparative test specimen was measured using a dial gauge.

The bulk density of the polyethylene resin foam, which is the material of the shock absorber body in test specimens 1 to 5 and comparative test specimens 1 to 6, was calculated by dividing the weight of the polyolefin resin foam by the volume. The closed cell ratio of the polyethylene resin foam was determined by the method described in ASTM D 2856.

(Natural frequency of floating floor structure)
Using test specimens 1 to 5 and comparative test specimens 1 to 6, the damped vibration waveform was measured based on the measurement method specified in JIS A 6322, the period was read from three adjacent peaks of the damped vibration waveform that became free vibration, and the natural frequency of the floating floor structure was calculated from the average value. Note that a load plate was placed on each of test specimens 1 to 5 and comparative test specimens 1 to 6 so that the live load was 550 kg/ ^m2 . The evaluation criteria for the natural frequency of the floating floor structure (buffer) in the cases of Examples 1 to 5 and Comparative Examples 1 to 6 were as follows:

◎: Less than 23 Hz ○: 23 Hz or more and less than 30 Hz △: 30 Hz or more and less than 50 Hz ×: 50 Hz or more (Dynamic spring constant)
In accordance with JIS A 6322, calculation was performed using the natural frequency obtained by the above method according to the following formula: where fn is the natural frequency (Hz), Kd is the dynamic spring constant (N/m ³ ), and B is the mass per unit area (Kg/m ² ).

fn=1/(2π)√(Kd/B)
(Distortion of the floating floor structure)
Load plates were placed on each of the test specimens 1 to 5 and the comparative test specimens 1 to 6 so that the live load was 550 kg/ ^m2 . Dial gauges were attached to the four corners of each of the test specimens 1 to 5 and the comparative test specimens 1 to 6, and the amount of displacement in the thickness direction was measured over time. After the load plates were placed, the amount of displacement (amount of distortion) of the height position of the upper surface of the buffer body main body after 100 days was used as an index of load resistance, with the height position of the upper surface of the buffer body main body after 1 day having passed as the standard. The evaluation criteria for the amount of deflection of the floating floor structure (buffer) in the cases of the examples 1 to 5 and the comparative examples 1 to 6 were as follows:

◎: Distortion amount is less than 2.5 mm (less than 5%)
○: Distortion amount 2.5 mm or more and less than 5 mm (5% or more and less than 10%)
×: Distortion amount 5 mm or more (10% or more)
(Floating floor construction costs)
The following evaluation index was determined based on the volume of the elastic body used per 1 ^m2 of the cushion body main body area. The evaluation criteria for the construction cost of the floating floor structure in the cases of Examples 1 to 5 and Comparative Examples 1 to 6 were as follows.

: 1.25× ^105mm3 or less ^◯ : More than 1.25× ^{105mm3 to} 2.50× ^105mm3 or ^less △: More than 2.50× ^{105mm3 to 5.00} × ^105mm3 or less ×: More than 5.00× ^105mm3 The evaluation results and overall evaluation of specimens 1 to ⁵ and comparative specimens 1 to 6 are shown in Table 1. The overall evaluation was based on the following criteria.

◎: Natural frequency is rated as "◎", and distortion and construction cost are rated as "○" or higher. ○: Natural frequency, distortion and construction cost are rated as "△" or higher. ×: One of the natural frequency, distortion and construction cost is rated as "×".

(Overall evaluation of Examples 1 to 5)
As shown in Table 1, in the case of Example 1, the natural frequency of the floating floor structure was rated as ⊚, the amount of distortion of the floating floor structure was rated as ◯, and the construction cost of the floating floor structure was rated as ◯. In the case of Example 1, the overall rating of the floating floor structure was ⊚.

In the case of Example 2, the natural frequency of the floating floor structure was rated as ○, the amount of distortion of the floating floor structure was rated as ◎, and the construction cost of the floating floor structure was rated as ◎. In the case of Example 2, the overall rating of the floating floor structure was ○.

In the case of Example 3, the natural frequency of the floating floor structure was rated as ○, the amount of distortion of the floating floor structure was rated as ◎, and the construction cost of the floating floor structure was rated as ○. In the case of Example 3, the overall rating of the floating floor structure was ○.

In the case of Example 4, the natural frequency of the floating floor structure was rated as ○, the amount of distortion of the floating floor structure was rated as ◎, and the construction cost of the floating floor structure was rated as △. In the case of Example 4, the overall rating of the floating floor structure was ○.

In the case of Example 5, the natural frequency of the floating floor structure was rated as ◎, the amount of distortion of the floating floor structure was rated as ◎, and the construction cost of the floating floor structure was rated as 〇. In the case of Example 5, the overall rating of the floating floor structure was ◎.

(Overall evaluation of Comparative Examples 1 to 6)
As shown in Table 1, in the case of Comparative Example 1, the natural frequency of the floating floor structure was rated as ⊚, the amount of distortion of the floating floor structure was rated as x, and the construction cost of the floating floor structure was rated as △. In the case of Comparative Example 1, the overall rating of the floating floor structure was x.

In the case of Comparative Example 2, the natural frequency of the floating floor structure was rated as ◎, the amount of distortion of the floating floor structure was rated as ×, and the construction cost of the floating floor structure was rated as ○. In the case of Comparative Example 2, the overall rating of the floating floor structure was ×.

In the case of Comparative Example 3, the natural frequency of the floating floor structure was rated as ◎, the amount of distortion of the floating floor structure was rated as ×, and the construction cost of the floating floor structure was rated as ◎. In the case of Comparative Example 3, the overall rating of the floating floor structure was ×.

In the case of Comparative Example 4, the natural frequency of the floating floor structure was rated as ×, the amount of distortion of the floating floor structure was rated as ○, and the construction cost of the floating floor structure was rated as ◎. In the case of Comparative Example 4, the overall rating of the floating floor structure was ×.

In the case of Comparative Example 5, the natural frequency of the floating floor structure was rated as ×, the amount of distortion of the floating floor structure was rated as ○, and the construction cost of the floating floor structure was rated as ○. In the case of Comparative Example 5, the overall rating of the floating floor structure was ×.

In the case of Comparative Example 6, the natural frequency of the floating floor structure was rated as ◎, the amount of distortion of the floating floor structure was rated as ×, and the construction cost of the floating floor structure was rated as ○. In the case of Comparative Example 6, the overall rating of the floating floor structure was ×.

(summary)
It was found that, as in the cases of Examples 1 to 5, when the dynamic spring constant of the buffer body is 10×10 ⁶ N/m ³ or less and the dynamic spring constant of the elastic body is 7×10 ⁶ N/m ³ or less, the load-bearing performance of the floating floor structure is sufficiently ensured while the vibration-proof performance of the floating floor structure is improved. Also, as in the case of Comparative Example 3, it was found that when the dynamic spring constant of the elastic body exceeds 7×10 ⁶ N/m ³ , the load-bearing performance of the floating floor structure is reduced. As in the case of Comparative Example 5, it was found that when the dynamic spring constant of the buffer body exceeds 10×10 ⁶ N/m ³ or less, the vibration-proof performance of the floating floor structure is reduced.

REFERENCE SIGNS LIST 10 Floating floor structure 12 Floor slab 14 Cushioning body 16 Floating floor portion 18 Cushioning body main body 18h Storage hole 18f Vibration insulation portion 20 Load support material 22 Elastic body 24 Thickness adjustment material

Claims (8)

A floating floor structure including a buffer body disposed on a floor slab and a floating floor portion disposed on the buffer body,
The buffer body is
a buffer body made of a polyolefin-based resin foam and having a receiving hole formed therethrough along the up-down direction;
a load support member disposed in the accommodation hole of the buffer body and configured to support the load of the floating floor section in response to compressive deformation of the buffer body due to the load of the floating floor section;
The load support member is
An elastic body;
a thickness adjusting member that is arranged so as to overlap the elastic body in the vertical direction, is configured to be more rigid than the buffer body and the elastic body, and adjusts the thickness of the load support member;
The dynamic spring constant of the buffer body when the load is 550 kg/m2 ^is 10×10 ⁶ N/ ^m3 or less;
A floating floor structure, wherein the dynamic spring constant of the elastic body when the load is 550 kg/m2 ^is 7 x ¹⁰⁶ N/ ^m3 or less. The floating floor structure according to claim 1, wherein the elastic body has a dynamic spring constant of 1 x ¹⁰⁶ N/m3 or ^more when a load of 550 kg/m2 is applied ^. The floating floor structure according to claim 1 or 2, wherein the ratio of the volume of the elastic body to the volume of each load support is 20% to 60%. The floating floor structure according to any one of claims 1 to 3, wherein the dynamic spring constant of the buffer body when the load is 550 kg/m2 ^is 2 x ¹⁰⁶ N/m3 or ^more . The floating floor structure according to any one of claims 1 to 4, wherein the ratio of the total area of the upper surfaces of all the load-bearing members to the total area of the upper surfaces of the buffer is 1% to 3%. The floating floor structure according to any one of claims 1 to 5, wherein the elastic body is made of high density polyurethane foam, and the density of the elastic body is 300 kg/m ³ to 800 kg/m ³ . The floating floor structure according to any one of claims 1 to 6, wherein the thickness adjusting material is made of at least one material selected from the group consisting of concrete, metal, wood, and synthetic resin. The bulk density of the polyolefin resin foam that is the material of the buffer body is 12 kg/m ³ to 20 kg/m ³ ;
The floating floor structure according to any one of claims 1 to 7, wherein the polyolefin resin foam has a closed cell rate of 80% or more.

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