JP3320026B2 - Hollow concrete slab structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow concrete slab structure in which a large number of box-shaped embedding members made of a synthetic resin foam molded article are embedded at predetermined intervals.

[0002]

2. Description of the Related Art There is known a method of constructing a hollow concrete slab using a box-shaped embedding material having a square shape in plan view made of a synthetic resin foam molded product such as styrene foam. As a construction mode, PC such as omnia plate
A mode in which a board is placed between walls and beams, and an embedding material is sequentially laid thereon at a predetermined position, and then cast-in-place concrete is poured from above to a predetermined thickness such that the embedding material is embedded and hardened. And, in the factory, a slab substrate in which an embedding material is fixed to a PC board is preliminarily manufactured, transported to a construction site and placed between walls and beams, and then the in-place cast concrete is buried from above. And hardening to a predetermined thickness.

[0003] In any of the construction methods, the constructed hollow concrete slab is lightweight,
It has the advantage of having a sound insulation performance almost equal to that of a solid concrete slab against an impact sound or the like. In addition, Japanese Patent Laid-Open No.
Japanese Patent Publication No. 284667 and Japanese Patent Application Laid-Open No. 1-287369 also propose a hollow slab structure in which the problem of sound insulation on the upper and lower floors of an apartment house having a hollow concrete slab is further improved.

[0004]

The present inventors have a great deal of experience with buildings having the above-mentioned hollow concrete slab structure, but in recent years, in actual buildings, the 1 kHz octave region which is likely to be unpleasant for residents is considered. (710Hz-1.4kHz) sound insulation performance (sound insulation performance against airborne sound such as television, stereo, and voice)
Have a tendency to decrease compared to other octave ranges. An object of the present invention is to suppress a decrease in sound insulation performance in a 1 kHz octave region in a hollow concrete slab structure.

[0005]

Means for Solving the Problems The present inventors have confirmed the following facts by conducting many experiments to solve the above-mentioned problems. There is a correlation between the sound insulation performance of the floor slab and the value of the natural frequency of the floor slab. In general, there are several equations for obtaining the natural frequency (primary natural frequency) under the fixed condition of a finite length flat plate, In the acoustic calculation for obtaining a high frequency such as the quality of sound insulation performance, the natural frequency f0. fix can be used appropriately. The hollow concrete slab is divided into a hollow part in which the embedding material is embedded and a solid part which is all concrete, and the solid part can be regarded as a fixed part. The natural frequency of the hollow concrete slab has a substantial effect on the sound insulation performance of the hollow concrete slab.

[0006]

(Equation 2)

A: Length (m) of one side (short side) b: Length (m) of other side (long side) h: Thickness (m) of plate E: Young's modulus of plate (N / m) ² ) σ: density of plate (kg / m ³ )

As shown in Equation 1, the natural frequency is proportional to the thickness of the plate and inversely proportional to the area. Therefore, in the case of a hollow concrete slab, the thinner of the concrete located on the upper or lower surface of the embedding material portion Thickness h of the concrete and the length a of one side (short side) of the embedded material and the length b of the other side (long side)
Is set appropriately, and the natural frequency of that portion is set to 1.4.
By designing the frequency to be higher than 1 kHz, a 1 kHz octave range (71
(0 Hz to 1.4 kHz).

The present invention is based on the above findings, and basically comprises a large number of box-shaped embedding members formed of a synthetic resin foam molded product and having a square shape in plan view at predetermined intervals. The length a of a side (short side) of the thinner concrete of the concrete located on the upper surface or the lower surface of the embedding material portion, which is an embedded hollow concrete slab structure.
(M), length b (m) of other side (long side), and thickness h
(M) is related to the natural frequency f0. fix is set to be equal to or higher than 1.4 kHz.

As described above, the natural frequency of the hollow portion is proportional to the concrete plate thickness h, and the natural frequency moves to a higher value as the plate thickness increases. However, the overall thickness of the slab is in consideration of construction costs, etc., and in practice, the upper limit is about 0.30 m. Assuming that, the thickness of concrete on the upper surface or lower surface of the embedding material is 0.06 m or more, respectively. 0.
About 10 m is a realistic thickness.

On the other hand, from Equation 1, the smaller the area of the embedded material (length a of one side × length b of the other side), the higher the natural frequency moves. However, in actual construction, due to the problem of workability, that is, as the size becomes smaller or smaller, a large number of embedding materials must be arranged on the concrete substrate, and the work amount increases and the practicality is lacking. . Therefore, it is practical to use a side having a length of about 0.40 m to 0.50 m or more.

Therefore, in a preferred embodiment of the present invention, the thickness t is in the range of 0.06 m to 0.10 m, and the length a of one side and the length b of the other side are in the range of 0.40 m to 0.50 m. And within the range, the natural frequency f0. fix is 1.4k
The length a (m) of one side, the length b (m) of the other side, and the thickness h (m) are selected so as to be higher than Hz. As a result, a hollow concrete slab structure with reduced sound insulation performance and construction cost can be obtained.

[0013] In a further preferred aspect of the present invention, the thickness of the concrete on the upper surface of the embedding material portion is larger than the thickness of the concrete on the lower surface. By doing so, in addition to the improvement of the sound insulation performance against the air propagation sound, the sound insulation performance against the floor impact sound can be improved at the same time. In a further preferred aspect of the present invention, the embedding material has a hollow portion opened on the back surface side. As a result, further reduction in the weight of the hollow concrete slab is promoted, and construction costs are reduced.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to examples. First, a general hollow concrete slab structure will be described with reference to FIGS. FIG. 1 shows an example of a hollow concrete slab structure CS. As shown in FIGS. 2 and 3, a thickness h1 is placed on a concrete substrate 3 having a thickness h1.
3, a box-shaped embedding material 1 having a square shape in plan view, which is a synthetic resin foam molded product as a lightening material, is fixed at a predetermined interval P, and a truss bar 2 or the like as a reinforcing material is interposed therebetween. The concrete slab substrate A is arranged and factory-produced.

After it is carried into the construction site and is placed between the beams B of the skeleton, as shown in FIG. 1, after the upper chord 2a of the truss bar 2 is used as a spacer and the upper slab upper bar 4 is attached. The cast-in-place concrete C is cast with a thickness H. Thereby, a hollow concrete slab structure having a thickness of H + h1 is constructed. It is also possible to manufacture only the concrete substrate 3 at a factory and fix the embedding material 1 at a construction site by an appropriate means. In the figure, 1a is the embedding material 1
Is a void formed on the back surface side of FIG.

FIG. 4 is a schematic view of a part of the concrete slab structure as viewed from above (the truss bars 2 and the like are omitted). As can be seen from FIG. 3, the concrete slab structure can be divided into a portion SA where the embedding material 1 exists and a portion SC where the embedding material 1 does not exist. Is a hollow portion. The solid portion SC can be regarded as a fixed portion when calculating the vibration of the slab, and the natural frequency of the hollow portion SA substantially affects the sound insulation performance of the hollow concrete slab CS.

Normally, in the case of a hollow concrete slab structure having a thickness of about 0.26 m, the thickness h1 of the concrete substrate 3
Is about 0.06 m, the length a of one side (short side) of the embedding material 1 is about 0.40 to 0.50 m, the length b of the other side (long side) is about 1.20 m in the past, and the thickness h3 is It is about 0.12 m. The thickness H of the cast-in-place concrete C is about 0.19 m, and in many cases, in the hollow portion SC, the thickness h1 of the concrete substrate 3 (0.06 m) <the thickness h2 of the cast-in-place concrete C on the embedding material 1. (H-h3 = 0.1
9−0.12 = 0.07 m) to improve the sound insulation performance against floor impact noise. The gap P between the embedding materials 1 and 1 is often set to about 0.15 m.

In the hollow concrete slab structure having the above structure, the quality of the sound insulation performance against the airborne sound is determined by:
Although it depends on the natural frequency (primary natural frequency) of the finite-length flat plate fixing condition, in the calculation of the sound to be obtained up to a high frequency such as the sound insulation performance, the natural frequency f0.
fix can be used appropriately.

[0019]

(Equation 3)

In Equation 1, a is the length (m) of one side (short side) of the hollow portion SA, and b is the length (m) of the other side (long side) of the hollow portion SA, that is, a and b are embedded materials 1
H is the thickness (m) of the thickness h1 of the concrete substrate 3 or the thickness h2 of the cast-in-place concrete C on the embedded material, whichever is smaller. E is the Young's modulus (N / m ² ) of the concrete plate, and σ is its density (kg / m ³ ).

Therefore, the 1 kHz octave range (710 Hz to 1.4 kHz) which is likely to be harsh for residents.
In order to improve the sound insulation performance in the building, the natural frequency of the thin concrete plate among the concrete plates in the hollow portion SA is designed to be 1.4 Hz or more, so that it is uncomfortable for residents. It is possible to prevent the sound insulation performance from deteriorating in the 1 kHz octave region, which is likely to cause the noise.

FIGS. 5 to 8 are based on the above considerations, and calculated by the above equation 1 when the length of one side of the embedding material 1 is fixed to 0.43 m and the length of the other side is changed. The change of the natural frequency is shown. Note that the Young's coefficient E (2.6 × 1
0 ¹⁰ N / m ² ) and the density σ (2300 kg / m ³ ). FIG. 5 shows that the thinner thickness h of the concrete plate is 0.0
6 shows a case where h is set to 0.07 m, FIG. 7 shows a case where h is set to 0.08 m, and FIG.
(FIG. 8).

As shown, the length a of one side of the embedding material
(M), other side length b (m) and concrete plate thickness h
(M) is adjusted appropriately to obtain the natural frequency f0. The fix can be appropriately set to be equal to or higher than 1.4 kHz, and the sound insulation performance can be improved by appropriately selecting the values in consideration of design conditions and the like.

In order to verify the result of the above calculation in an actual building, two types of embedding materials 1B having different shapes (sizes) (dimensions a: 0.43 m × b: 1.2 m × h3:
0.12m) (conventional type) and 1A (dimension a: 0.43
m × b: 0.43 m × h3: 0.12 m) (improved type) to manufacture a concrete slab substrate having the shape shown in FIG. The slab was constructed, and the average sound pressure level difference between the rooms (that is, the value indicating the sound insulation performance for the sound (such as television and speech) transmitted through the air between the two rooms in the building) was measured. The measurement was performed in the area of about 100 m ² dwelling units living room (about 18m ^2), according to JIS1417 "method of measuring the sound pressure level difference in the field of building unit", an acoustic device installed in one room (source room) ( One octave band noise was generated from the amplifier and the speaker, and the sound pressure level of the test sound was measured in the sound source room and the other room (sound receiving room). The evaluation method of the room sound pressure level is based on JIS
Compliant with A1418 “Sound insulation grade of buildings”.

The overall thickness of the hollow concrete slab used in the experiment was 0.26 m, and the concrete substrate 3
Has a thickness h1 of 0.06 m, and the thickness H of the cast-in-place concrete C is 0.19 m. Therefore, in both cases, the thickness h2 of the concrete plate on the embedding material is 0.07 m. Further, the Young's modulus E and the density σ of the concrete plate were set to substantially the same values as in the above calculation.

FIG. 9 is a graph showing the results. The white circles indicate the case of a hollow concrete slab using the embedding material 1B, and the black circles indicate the case of a hollow concrete slab using the embedding material 1A. The natural frequency f0. fix is 1.2 kHz, and the natural frequency f0. fix is 1.8kHz
It is. The graph shows that the hollow concrete slab having the embedding material 1A has a 1 kHz octave range (710 Hz to 1.4 k) as compared with the hollow concrete slab having the embedding material 1B.
Hz), indicating a clear improvement in performance, which satisfied the performance of D-50. This demonstrates the effectiveness of the present invention.

[0027]

According to the present invention, it is possible to easily construct a hollow concrete slab structure in which sound insulation performance in a 1 kHz octave region, which is likely to be harsh for residents, is surely improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a hollow concrete slab structure.

FIG. 2 is a diagram illustrating a substrate for a hollow concrete slab.

FIG. 3 is a diagram illustrating a hollow concrete slab structure in cross section.

FIG. 4 is a diagram illustrating a state in which a part of the hollow concrete slab structure is viewed from above.

FIG. 5 is a graph showing a relationship between a natural frequency of a hollow concrete slab structure and dimensions of an embedding material.

FIG. 6 is a graph showing a relationship between a natural frequency of a hollow concrete slab structure and dimensions of an embedding material.

FIG. 7 is a graph showing a relationship between a natural frequency of a hollow concrete slab structure and dimensions of an embedding material.

FIG. 8 is a graph showing the relationship between the natural frequency of the hollow concrete slab structure and the dimensions of the embedding material.

FIG. 9 is a graph showing a change in sound insulation performance actually brought about by a difference in dimensions of an embedding material in a hollow concrete slab structure.

[Explanation of symbols]

A: Concrete slab substrate, C: Cast-in-place concrete, CS: Hollow concrete slab structure, SA: Hollow portion, SC: Solid portion, h1: Thickness of concrete substrate, h
2: Thickness of cast-in-place concrete in hollow part, h3: Thickness of embedded material, H: Thickness of cast-in-place concrete in solid part, 1: Casting material

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Terumaro Nagai 1-5-3 Midori, Kurihashi-cho, Kitakatsushika-gun, Saitama (56) References JP-A-9-250196 (JP, A) JP-A-1-284667 ( JP, A) JP-A-10-148005 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) E04B 5/32 E04B 5/43

Claims (4)

(57) [Claims] 1. A hollow concrete slab structure formed by embedding a large number of box-shaped embedding materials having a square shape in plan view made of a synthetic resin foam molded article at predetermined intervals, and comprising: The length a (m) of one side (short side), the length b (m) of the other side (long side), and the thickness h of the thinner concrete of the concrete located on the upper surface or the lower surface of the filling material portion
(M) is related to the natural frequency f0. A hollow concrete slab structure, wherein fix is set to be 1.4 kHz or more. (Equation 1) E: Young's modulus (N /
m ² ) σ: Density of the concrete plate (kg / m ³ ) 2. The thickness h is in a range of 0.06 m to 0.10 m, and the length a of one side and the length b of the other side are 0.40 m to 0.40 m.
0.50 m, and within this range, the natural frequency f0. f
The length a (m) of one side of the thinner concrete of the concrete located on the upper surface or the lower surface of the embedding material portion, and the length b of the other side so that ix is 1.4 kHz or more.
The hollow concrete slab structure according to claim 1, wherein (m) and a thickness h (m) are selected. 3. The hollow concrete slab structure according to claim 1, wherein the concrete thickness of the upper surface of the embedding material portion is larger than the concrete thickness of the lower surface. 4. The hollow concrete slab structure according to claim 1, wherein the embedding material has an open space on the back side.