JPH1037345A - Concrete structural body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure having light weight, allowing mass production at a plant or the like, further allowing a condition to be easily established for obtaining desired characteristics, and forming no shielding obstruction. SOLUTION: Reinforcements 11 are buried in concrete 12 as per prescribed arrangement, thereby forming a PC panel 10. In this case, the length L of horizontal reinforcements 11b extending in an electrical field direction is decided to suit a radio frequency as an object desired for suppression. As one example, the length L is taken at a value equal to 5m for allowing the transmission of a 100MHz frequency. Also, when a gap G between the horizontal reinforcements 11b is too small, a plurality of the horizontal reinforcements 11b become substantially equivalent to a single and long horizontal reinforcement. For this reason, the prescribed gap G (e.g. 60mm) is maintained. When a building is constructed by use of the PC panel 10 so formed, TV radiowaves are transmitted through the PC panel 10, and a TV ghost due to a reflection does not appear. In addition, TV radiowaves not so much attenuated can reach even a house behind the building, and the occurrence of a shielding obstruction can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete structure, and more particularly to a concrete structure suitable for a television ghost countermeasure used in a high-rise building or the like and for enabling normal transmission of radio waves transmitted and received by communication equipment. About things.

[0002]

2. Description of the Related Art Conventional TV ghost countermeasures include, for example, JP-B-55-13600 and JP-B-55-13600.
As shown in JP-A-49798, a structure in which a large number of tiles made of a ferrite sintered body having good electromagnetic wave absorption characteristics in a VHF band or a UHF band are generally attached to an outer wall surface of a building (high-rise building) such as concrete. It is being done.

[0003] The above-mentioned invention is a basic patent,
After that, various improvements have been made. However, the layout of tiles made of sintered ferrite and the method of attachment are improved, and tiles (ferrite plates) are used as a reference.

FIG. 9 shows an example of a radio wave absorbing curtain wall for a TV ghost using such tiles. That is, a tile 2 made of a ferrite sintered body is attached to the surface of the concrete 1 constituting the outer wall at a predetermined interval, and a decorative plate 3 is bonded and integrated on the surface. Further, inside the concrete 1, a reinforcing bar 4 assembled in a lattice shape is embedded.

[0005] Focusing on the actual manufacturing process,
The tile 2 is attached to a predetermined position on the back surface of the decorative plate 3 using an adhesive, and then the reinforcing bar 4 is disposed at a predetermined distance (for example, about 3 cm) using the fixing hardware 5. In this state, a concrete form (not shown) covering the periphery is installed, and then concrete is poured (thickness: 15 cm) to manufacture (the thickness of the entire curtain wall is 17 cm).
About). Therefore, the tile 2 is buried in the concrete 3.

[0006]

However, in the case of using the conventional ferrite sintered body tile 2 described above, since the ferrite sintered body itself is very heavy, the tile 2 made of such ferrite sintered body is stuck. A problem arises in the workability and safety of wearing. In addition, since the tile 2 has a very small planar shape of only about 100 mm square, the sticking operation becomes very complicated.

Further, since the tile 2 made of a ferrite sintered body is heavy, it is necessary to have strength for holding it and exhibit a fireproof function, so that the thickness of the concrete 3 is increased as described above. The weight on the three side also increases. For example, standard size 4
mx 3.2m lightweight concrete (specific gravity 1.2)
Even if it is made by using the concrete, the weight of the concrete 3 alone is 30
There is also 0 kg.

As a result, the entire building becomes extremely heavy, and foundation work and steel work must be performed to support the weight of the building, which makes the processing complicated and prolongs the work and increases the cost.

Further, the radio wave absorption characteristics slightly vary depending on the composition and dimensions of the ferrite constituting the tile 2.
Therefore, it is necessary to dimension the tile 2 with high precision, but it is difficult to accurately dimension the tile 2 in combination with shrinkage during sintering. In addition, there is a possibility that cracks or chips may occur after manufacturing, and the tile in which such a situation occurs becomes a defective product. Therefore, due to the difficulty in dimensioning and the cracks and the like, the yield at the time of manufacturing a tile having desired characteristics is poor, and the cost is further increased. Further, in practice, determination of a dimension and a shape having desired characteristics is also performed through trial and error, and a complicated process is required because the shrinkage ratio varies.

In order to solve such a problem, recently, a ferrite grain has been directly mixed into concrete, and the mixed ferrite grain has been used to absorb radio waves.

However, such a method has poor radio wave absorption characteristics as compared with a tile made of the above ferrite sintered body, and requires a thickness of about 30 cm in order to obtain desired absorption characteristics. , Which cannot be used for actual construction. Furthermore, in addition to the above thickness, as a factor for obtaining the desired absorption characteristics, it is necessary to optimally set a plurality of conditions such as the particle size of the ferrite particles and the mixing amount and ratio. Obtaining the condition itself becomes complicated.

Further, the conventional TV ghost countermeasures are as follows.
In any case, by providing a radio wave absorbing structure on the outer wall, the radio wave reflected by the reinforcing bar 4 is absorbed in the wall,
We do not reflect radio waves around the building. As a result, for example, for a house located on the back side of the building with respect to the traveling direction of the radio wave, a radio wave of a desired level is difficult to reach, a darkening as a whole, or a shielding obstacle that generates noise is generated. There is also a problem that occurs.

The present invention has been made in view of the above-mentioned background, and has as its object to solve the above-mentioned problems, to have a large planar shape and a small thickness, and to have a light weight. To provide a concrete structure that can be mass-produced in factories and the like, can easily install PC panels and curtain walls, can easily determine conditions for obtaining desired characteristics, and has no obstruction to shielding. It is in.

[0014]

In order to achieve the above-mentioned object, in a concrete structure according to the present invention, in a reinforced concrete structure in which a reinforcing bar is embedded in a concrete at a predetermined arrangement, the reinforcing member is provided in a direction of an electric field in the reinforcing bar. Set the length of the extending horizontal reinforcing bar to a length suitable for the frequency of the radio wave whose reflection is to be suppressed. The radio wave having the frequency is transmitted through the concrete (claim 1).

In the case where the width of the concrete in the electric field direction is twice or more the length of the horizontal reinforcing bars, a plurality of the horizontal reinforcing bars are arranged in a horizontal line with a predetermined gap. (Claim 2).

[0016] Preferably, the plurality of horizontal reinforcing bars arranged in a horizontal row are connected by a non-conductive connecting member to be integrated (claim 3).

Further, the structures having the above-described structures can be specifically applied to building wall materials such as precast concrete panels, curtain walls, and outer and inner walls of buildings (claim 4).

Conventionally, in a reinforcing bar generally used for a building, a TV radio wave is reflected by the reinforcing bar. However, by setting the length of the horizontal reinforcing bar to a predetermined size, a predetermined size specified by the size is obtained. Radio waves in the frequency domain are transmitted without being reflected. Therefore, if the frequency range is set to, for example, the frequency of the TV radio wave, the TV radio wave hitting the wall surface of the building is transmitted as it is and enters the building.
Therefore, the reflected wave does not go to the house on the near side of the building, so that there is no radio interference such as TV ghost.

Further, since the light is transmitted as described above, it passes through the building as it is and is emitted to the outside from the opposite wall surface. Therefore, for the house installed on the back side of the building, T
Since the V radio wave arrives directly, the shielding obstacle is also eliminated.

Further, when transmitting and receiving radio waves with a communication device such as a mobile phone or a wireless LAN, if the length of the reinforcing bar is set to match the frequency of the transmitted and received radio waves, the radio waves irradiated on the wall surface are not reflected. Therefore, there is a high possibility of using a mobile phone even in a relatively deep place in a building, and there is no malfunction due to irregular reflection on a wall surface in a wireless LAN or the like.

Further, according to the structure of the second aspect, even in the case of a wide concrete structure, the horizontal reinforcing bars can be arranged almost over the entire area, and a desired strength can be obtained. In particular, according to the structure of the third aspect, since a plurality of horizontal reinforcing bars are connected to one in the horizontal direction, a predetermined gap is maintained when the horizontal reinforcing bars are arranged in the formwork when the concrete is poured. It can be inserted and arranged in a state where it is placed, which facilitates the operation.

The rebar according to the present invention includes not only the rebar in a building but also a wire having a small diameter, and the material is not limited to iron but may be any metal.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a precast concrete (P) as an example of a concrete structure according to the present invention.
C) One embodiment of the panel is shown. That is, similar to the ordinary PC panel 10, the reinforcing bars 11
Is buried in the concrete 12. At this time, the materials used for the concrete PC panel 10 can be used as the material constituting the concrete 12 and the mixing ratio of each material. The material of the reinforcing bar 11 can be the same as the conventional one.

Here, in the present invention, a radio wave of a desired frequency is transmitted by appropriately setting the length L of the reinforcing bar 11. That is, as shown in the drawing, the reinforcing bars 11 assembled in a lattice shape are constituted by the vertical reinforcing bars 11a extending in the vertical direction and the horizontal reinforcing bars 11b extending in the horizontal direction. And
As is known, the direction of the electric field and the direction of the magnetic field are orthogonal.
In the radio wave of V broadcast, the electric field direction is on a horizontal plane. Therefore, as shown in FIG. 3B, the horizontal reinforcing bar 11b becomes a reinforcing bar extending in the electric field direction.

The reinforcing bar that reflects radio waves is the horizontal reinforcing bar 11b that matches the direction of the electric field. Therefore, the arrangement of the horizontal reinforcing bars 11b contributes to the reflection and transmission of radio waves, and the length L, L
A gap d between the horizontal reinforcing bars 11b arranged vertically and a gap G between the two horizontal reinforcing bars 11b arranged in the horizontal direction.
There are three types. Since the vertical reinforcing bar 11a extends in the direction of the magnetic field, it does not affect the reflection of radio waves.
Length and the like can be set arbitrarily.

Of the above three factors, the interval d is
Since it is not directly related to the direction of the electric field, it can take any value. In other words, to obtain strength, shorten d,
What is necessary is just to determine according to the design of the normal PC panel 10.

If the gap G is too narrow, it becomes in the same state that the adjacent horizontal reinforcing bars 11b are substantially connected to each other, and becomes longer than the desired length L. Therefore, they need to be separated by a certain distance or more. And
As a result of the experiment, there was no effect on the transmission / reflection characteristics even when approaching 30 mm. The upper limit of the gap G is not particularly limited in relation to the main part of the present invention. That is, the gap G
Has no effect on transmission / reflection characteristics. However, if it is too large, there is a risk that the strength of the PC panel 10 may be increased.
Appropriate intervals are taken into account in consideration of the strength and the like as in the panel design.

Therefore, what affects the transmission / reflection characteristics is the length L of the horizontal reinforcing bar 11b. Then, to give an example, in order to obtain an effect in a frequency band around 100 MHz, the length L is set to about 5 m. Also, 2
In order to obtain an effect in a frequency band near 00 MHz, the length L is set to about 3.4 m. Then, as an example of the transmittance curve of the present embodiment (L = 5 m), as shown in FIG. 2, it can be confirmed that almost 100% of light is transmitted near 100 MHz. This kind of transmission means that
Naturally, the reflected wave can be said to be almost zero.

By adopting such a configuration, the outer wall for TV ghost countermeasures according to the present invention can be arranged on the wall surface of the building without any difference from the ordinary PC panel construction. Such PC panels can be mass-produced in factories, and their size is on the order of several meters.
Compared to the conventional ferrite sintered tiles, the size is large and the construction is easy.

As a result, as shown in FIG. 3, it is assumed that a TV wave is applied to a building (building) 20. This building 20
If the PC panel of the present invention is mounted on the outer wall of
Since the V radio wave passes through the PC panel, a reflected wave as shown by a broken line in the figure does not occur, passes through the inside of the building 20, and is emitted to the outside from the opposite wall surface. Therefore, since the reflected wave does not reach the house 21 located on the front side of the building 20, only the direct TV radio wave is received, and no TV ghost occurs. Further, in this example, the TV radio wave is transmitted to the building 20.
House 2 located on the opposite side of building 20 because it passes through
Since the transmitted TV radio wave also reaches 2, the shielding obstruction can be eliminated.

* Experimental results A reinforcing bar having a diameter of 10 mm was used, a vertical reinforcing bar used for a normal PC panel was used, and a horizontal reinforcing bar was set at a distance d of 50.
mm, the cap G is 60 mm, and the length L is 3.4.
m, 4 m, and 5 m were manufactured, and the reflection coefficient with respect to frequency was determined. FIG. 4 shows the results.

As is apparent from the drawing, it is understood that by changing the length L, the frequency band that does not reflect changes. And it was confirmed that almost 100% of the light was not reflected in a certain frequency band regardless of the length. Therefore, by adjusting the frequency at which the reflection coefficient is substantially zero to the frequency of the TV radio wave, it is possible to eliminate the reflection disturbance (TV ghost). Further, as can be seen by comparing the transmission characteristic shown in FIG. 2 and the graph of the reflection coefficient characteristic with the length L = 5 m in FIG. 4, the two characteristics are opposite to each other. It can be said that it is transmitted as it is. In other words, although a specific illustration is omitted,
Even with the length L = 4, 3.4 m, the radio wave in the frequency band where the reflection coefficient is almost 0 is almost 100% as it is.
It can be said that it is transparent.

Further, although not shown, the interval d is set to 1
A product expanded to 00 mm was manufactured and the same experiment as above was performed, but the obtained characteristics were almost the same as those shown in FIG.

On the other hand, as a comparative example, a reinforcing bar having a conventional structure (the length of the horizontal reinforcing bar is sufficiently long) was used (the reinforcing bar diameter was 10 m).
m, d = 50 mm), and the reflectance characteristic with respect to the frequency was obtained. As a result, as shown in FIG.
It was confirmed that radio waves in a frequency band of about z were almost reflected and could not be used as a measure against TV ghost.

It should be noted that the present invention is not limited to the TV ghost described above, and for example, as shown in FIG.
= 15 mm rebar (wire) 11'b is arranged in the horizontal direction (gap G '= 1,5 mm, interval d' = 5 mm)
As a result, as shown in FIG. 7, the reflection characteristic can be suppressed at about 1 GHz. That is,
A wall material that can transmit radio waves in a frequency band of about 1 GHz can be configured. Therefore, by using such a structure, for example, a transmission / reception radio wave of a mobile phone or a PHS can be transmitted through the wall material, so that even a person located at the center of the building can use the mobile phone. In addition, in the thing shown in FIG. 6, the thing of 4 mm was used as a reinforcing bar. This is because the length L was very short, 15 mm, to balance it, and to obtain the effect of the present invention. The rebar diameter may be large. Similarly, the gap G ′ and the interval d ′ are not limited to the illustrated example, but may be arbitrary.

On the other hand, in each of the above-described examples, a plurality of horizontal reinforcing bars 11b are arranged in the PC panel in the horizontal direction.
Although a predetermined gap is provided between adjacent horizontal reinforcing bars 11b, the present invention is not limited to this.
Of course, a configuration in which one 1b is arranged in the horizontal direction may be adopted. That is, when the width of the PC panel is substantially equal to the length of the horizontal reinforcing bar 11b, only one PC panel can be physically arranged in the horizontal direction.

The arrangement of the horizontal reinforcing bars 11b with a predetermined gap G in one PC panel is not only complicated in the first place, but also the horizontal reinforcing bars 11b in the horizontal direction. 11b It is necessary to adjust the relative positions of the two panels 11b, which complicates the manufacturing operation. However, if the length of the PC panel is set so that there is only one in the horizontal direction, the distance d does not affect the characteristics. Thus, the reinforcing bars can be roughly arranged, and the PC panel can be manufactured very easily.

On the other hand, as shown in FIG.
For example, as shown in FIG. 8, as shown in FIG. 8, a plurality of horizontal reinforcing bars 11 b are connected with a fixed gap G by a connecting member 24 to manufacture a single reinforcing bar, and the When a PC panel is manufactured by assembling, not only the gap G can be set to a predetermined distance or more, but also the horizontal reinforcing bar is physically one, so that the assembling work is facilitated. The connecting member 24 is made of synthetic resin or F
Any material may be used as long as it is a non-conductive material such as RP. Also,
Instead of covering and connecting only the ends of the horizontal reinforcing bars 11b as shown in the figure, it is of course possible to cover the entire length.

In the above-described embodiments, all examples applied to the PC panel have been described. However, the present invention is not limited to this, and may be a curtain wall or the like.
Furthermore, the present invention can be applied to a case where concrete is directly poured on site. The installation place is not limited to the outer wall of the building, but may be an inner wall or a partition wall, and is not limited to the building.

[0040]

As described above, in the concrete structure according to the present invention, radio waves in a predetermined frequency band can be transmitted without being reflected by the reinforcing bar. Therefore, when taking measures against TV ghosts, if the frequency band of the target TV radio wave is transmitted, the TV radio wave will be transmitted without being reflected on the wall surface, so that the occurrence of radio interference such as TV ghost etc. is possible. Can be suppressed. In addition, since radio wave absorbers are not used as in the past, radio waves can be transmitted and TV radio waves can reach the rear side of the concrete structure without much attenuation, eliminating shielding obstacles. it can.

Since it is not necessary to use a radio wave absorber as in the prior art, and the constituent members may be ordinary concrete structures such as concrete and reinforcing steel, the weight increases to prevent TV ghosts. Without this, it becomes a very lightweight structure.

Further, since the characteristic is caused by the length of the horizontal reinforcing bar, the effect of the present invention can be obtained even if the reinforcing bar is cut with high accuracy and the concrete is cast relatively roughly. Of course, it is natural to manufacture so as to function as a structure such as a building, etc.), so the incidence of defective products is reduced as much as possible compared to the conventional one using ferrite tiles .

Furthermore, the weight is lighter than that in which ferrite grains are mixed in concrete, and the factor for determining the characteristics is small only by the "length of the horizontal reinforcing bar". It is easy to design and can be manufactured as designed.

Furthermore, by appropriately changing the length of the horizontal reinforcing bar, the frequency band to be transmitted can be made arbitrary. For example, if the frequency band is adjusted to the GHz band radio wave used in a mobile phone or a wireless LAN, The communicable area is expanded, and the possibility of malfunction due to diffuse reflection is suppressed as much as possible.

In addition, the dimensions and the shape of the concrete structure can be the same as those of a normal concrete structure except that the width is equal to or longer than the length of the horizontal reinforcing bar. In addition, the planar shape is large and the wall thickness can be reduced. Then, mass production at a factory or the like is possible, and the PC panel and curtain wall can be easily installed.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of a PC panel according to the present invention.

FIG. 2 is a diagram showing characteristics of FIG. 1;

FIG. 3 is a diagram illustrating the operation and effect of the present invention.

FIG. 4 is a graph showing experimental results for demonstrating the effect of the present invention.

FIG. 5 is a graph showing experimental results on a conventional structure as a comparative example.

FIG. 6 is a diagram showing another embodiment of the present invention.

FIG. 7 is a graph showing characteristics of the embodiment shown in FIG.

FIG. 8 is a diagram showing a modification.

FIG. 9 is a diagram showing a conventional example.

[Explanation of symbols]

 10 PC panel 11b Horizontal bar 12 Concrete L Length of horizontal bar

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Makoto Ishikura 5-36-11 Shimbashi, Minato-ku, Tokyo Inside Fuji Electric Chemical Co., Ltd.

Claims (4)

[Claims] In a reinforced concrete structure (10) in which reinforcing bars (11) are embedded in a predetermined arrangement in concrete (12), a length (L) of a horizontal reinforcing bar (11b) extending in an electric field direction among the reinforcing bars. A length suitable for the frequency of the radio wave whose reflection is to be suppressed, and the radio wave of the frequency is transmitted through the concrete. 2. The concrete structure according to claim 1, wherein a width of the concrete structure in an electric field direction is at least twice as long as the length of the horizontal reinforcing bars, and a plurality of the horizontal reinforcing bars are arranged in a horizontal row with a predetermined gap (G). The concrete structure according to claim 1, wherein: 3. The concrete structure according to claim 2, wherein the plurality of horizontal reinforcing bars arranged in a horizontal row are connected and integrated by a non-conductive connecting member. 4. The structure according to claim 1, wherein the structure is applied to a building wall material such as a precast concrete panel, a curtain wall, an outer wall or an inner wall of a building. Concrete structure.