JPH0756182B2 - Vibration suppression device for buildings - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vibration suppressing device that suppresses vibration caused in a building by an earthquake, wind, or the like.

“Conventional technology and its problems” Due to factors such as the development of high-strength materials, the progress of machining technology, and the development of structural analysis technology using computers, recent buildings have become larger, diversified in form, and lightweight. As it becomes more and more popular, the structure is becoming more flexible. And
In such a lightweight and flexible building, the natural frequency is low and the vibration damping tends to be small.
In particular, various unexpected vibrations may occur due to the influence of aerodynamic external force due to wind.

Therefore, in order to cut off this type of vibration source, it is conceivable to apply aerodynamic measures to the outer shape of the building, but there are various restrictions on the outer shape of the building in terms of function or design. It is difficult to rely on this aerodynamic measure alone.

Therefore, the inventor of the present application has filed Japanese Patent Application No. 60-241045
-101764) In the specification, at the required position of the building,
Proposal of a vibration suppression device that can hold a tank that stores a liquid that vibrates in the same cycle as the building's unique vibration cycle and with a phase difference, and suppress the rolling of the building due to the vibration of the liquid However, the above-mentioned problem is solved.

However, in addition to rolling,
When the center of gravity of a building and the center of gravity of the building are deviated from each other, a rotational motion generated by receiving aerodynamic force due to wind, that is, a swinging rotation of the building may occur.

In view of the above problems, the present invention has been made by developing a vibration suppressing device proposed by the inventor of the present application, in which vibration mainly caused by rolling of a building caused by wind,
Another object of the present invention is to provide a device capable of suppressing both vibrations caused by swinging and rotating.

[Means for Solving Problems] In order to achieve the above object, the invention according to claim 1 provides a tank for storing a liquid in a building, and the liquid in the tank is a side wall of the tank. It is supposed to vibrate in the same natural vibration cycle as the building specific vibration cycle between,
The tank has a space that allows the vibration of the liquid above the liquid surface of the liquid in a stationary state, and a plurality of adjusting members are provided so as to project from the inner surface of the tank. , Are arranged substantially in the radial direction of the tank, and are arranged along the inner circumference of the tank. Further, the invention according to claim 2 is provided by stacking a plurality of tanks for storing liquid in a building, and the liquid in each tank is unique to the building between the side walls of the tank. The tank vibrates in the same natural vibration cycle as the vibration cycle, and each of the tanks has a space above the liquid surface of the liquid in a stationary state, which allows vibration of the liquid, and a plurality of adjusting members at the bottom thereof. Is provided so as to project from the inner surface of the tank, and the adjusting member is provided by connecting the tank located on the lower side and the tank located on the upper side.

"Operation" When vibration acts on a building due to an earthquake or wind, the liquid stored in the tank vibrates in the same natural vibration cycle as the building and with a phase shift, In addition to suppressing vibration centering on rolling, when the building swings due to an earthquake or wind, vibration occurs,
The liquid that moves in the circumferential direction of the tank due to the swinging rotation is subjected to resistance by the adjusting member to generate a turbulent flow, thereby suppressing the swinging rotation. Further, since a plurality of tanks are stacked in a multi-stage manner and the upper and lower tanks are connected by a plurality of projections, the vibrations of the liquid can be effectively suppressed by these projections, and the tanks stacked on top and the inside thereof The liquid load can be reliably supported from below.

"Embodiment" FIGS. 1 to 3 show a building such as a high-rise building provided with a vibration suppressing device according to an embodiment of the present invention. A support base 2 having a laminated structure of an elastic body such as rubber and a steel plate is provided on the rooftop that is considered to be most effective against the generated vibration, and a tank 3 for suppressing vibration is provided on the support base 2. Is provided.

The tank 3 is a cylindrical tank for storing drinking water of the building 1 or fire protection water, and has a structure with an open upper part, as shown in FIGS. 2 and 3. The liquid W is formed to have an outer dimension and has the same natural vibration period as that of the building 1.
By storing the water, the vibration of the building caused by the wind etc. is suppressed. The tank 3 has a space above the liquid surface of the liquid W in a stationary state to allow the movement of the liquid W, and a plurality of adjusting ribs (adjusting members) contacting the side wall of the tank 3 in the peripheral portion of the bottom surface thereof. 3a is formed. These adjusting ribs 3a are formed at a height so as to be submerged in the liquid W stored in the tank 3, further spaced from each other along the circumferential direction of the tank 3 by a predetermined distance, and each of them is a bottom surface of the tank 3. It is formed so as to extend radially from the central portion. Further, inside the bottom surface of the tank 3, an adjusting rib (adjusting member) 3b having the same size as the adjusting rib 3a is provided.
Are formed so as to extend radially from the center of the tank 3, and adjustment ribs (adjustment members) 3c that extend radially are also formed at the center of the bottom surface of the tank 3.

The liquid W in the tank 3 is stored in a depth such that the natural vibration cycle is the same as the natural vibration cycle of the building 1, thereby suppressing the vibration of the structure 1 caused by the wind.

Further, when the center of gravity and the center of gravity of the building 1 are deviated and the building 1 is swung, the liquid in the tank tends to flow in the circumferential direction of the tank 3, In this case, since the adjusting ribs 3a, 3b, 3c serve as a flow resistance of the liquid, the liquid flows in the circumferential direction of the tank 3 with the same period as the swing period of the building 1 and a phase shift, Also suppresses this swinging rotation.

Therefore, according to the vibration suppressing device having the above structure, it is possible to suppress both the vibration centering on the rolling of the building 1 and the vibration centering on the swing rotation.

By the way, the liquid W stored in the tank 3 is required to generate vibrations out of phase with the same cycle as the cycle of the building 1.
Therefore, when the tank 3 that does not include the adjusting members 3a, 3b, 3c is used, since the damping rate for the vibration of the liquid W itself is small, the effect of vibrating on the contrary is obtained unless a liquid having a viscosity higher than that of water is used. May bring. However, in the structure of the present invention, the damping rate of the liquid itself stored in the tank 3 can be adjusted by adjusting the width and size of the adjusting members 3a, 2b, 3c and the number of the adjusting members 3a, 2b, 3c regardless of what kind of building 1 is applied. The damping factor of the entire structure can also be adjusted. The width of each adjusting member is 30m in diameter.
It is estimated that about 5 cm should be set in a tank of a certain size. Here, as the adjusting members 3a, 3b, 3c, a rib structure is shown in the illustrated example.
3a, 3b, 3c are provided for giving flow resistance to the liquid W. From this point of view, regarding the shape and structure of each adjusting member, for example, a perforated plate-like one, a lattice-like one, It is also possible to employ members in the form of mesh, and the arrangement relationship and size of these members will be determined as necessary.

FIG. 7 shows a second embodiment of the present invention. In this embodiment, the tank 3 is formed by forming a plurality of bottom walls 3d.
The inside of the container has a multi-layer structure in which it is vertically divided into a plurality of small chambers 3e, and each bottom wall 3d is supported by a plurality of pillar-shaped adjusting members 3f provided upright inside the tank.

In this embodiment, the adjustment member 3f adjusts the attenuation of the stored liquid W, and the adjustment member 3f supports the bottom wall 3d. In this embodiment as well, the same effect as that of the above embodiment can be obtained. You can In this example,
The small chambers 3e of the tank 3 have the feature of being able to store different kinds of liquids, and the damping effect can be adjusted by adjusting the volume and viscosity of the liquids stored in the small chambers 3e.

In the following, Japanese Patent Application No. 60-241045 (JP-A-62-101764)
No.) Describe the vibration analysis of the building 1 and the tank performed in the specification.

First, when analyzing a tank having no adjustment ribs 3a, 3b, 3c, the tank and the building 1 exhibit vibration characteristics similar to the vibration model shown in FIG.

The vibration model shown in Fig. 4 is based on the mass of spring 4A with spring constant K _0.
A vibration system A (a vibration model of a building) that supports a body 5A of M ₀ and adds a dashpot 6A with a damping rate h ₀ , and a body of effective mass M ₁ to a spring 4B having a spring constant K ₁ 5B
Vibration system B (vibration model inside the tank) that supports a dashpot 6B with damping rate h ₁
It consists of and.

In such a vibration model, when the vibration system A starts to vibrate due to an external force applied to the object 5A, the vibration system B
Starts to vibrate with a phase difference of 1/4 cycle, so that the vibration of the vibration system A can be suppressed by matching the natural vibration cycles of the vibration systems A and B.

Here, the natural vibration period of the vibration system is And the natural vibration period T ₀ of the construct 1 is
Since it is uniquely determined by the mass M ₀ and the spring constant K ₀ determined from the viewpoint of structural design, in order to make the natural vibration period T ₁ of the liquid W stored in the tank 3 coincide with the above T ₀ ,
The size and the capacity of the tank 3 are set so that they match.

That is, according to the Hausner theory that holds for the behavior of the stored liquid in the tank, the tank 3
The free water effective mass (mass acting as a vibrating body) M ₁ that can move inside is given by the following equation (2).

However, H: distance from the bottom of the tank 3 to the water surface R: radius of the tank 3 M: mass of liquid actually stored in the tank 3 and the natural frequency ω of the stored liquid W (so-called The natural frequency of sloshing) is given by the following equation (3).

Further, from the natural frequency ω, the natural vibration period T is obtained as shown in the following equation (4).

If, for example, R = 15 m H = 2 m M = 1414 t (subsequently, M = 812 t) is substituted for the above parameters, T = 11.7 seconds.

Then, between the natural vibration period T ₁ of the liquid in the tank and the natural vibration period T ₀ of the building obtained by the above formula, T ₀ = T ₁ ……………… (5) Formula is established. As described above, each size and storage amount of the tank 3 are set.

The characteristics shown in FIGS. 5 and 6 were obtained from the experimental results of the displacement response magnification excited by the vibrating table. Fifth
The figure shows the result of an experiment carried out with the liquid (water) stored in the tank, and FIG. 6 shows the result of the experiment carried out with the tank being empty.

That is, as shown in FIG. 6, by providing a tank in a building having a large amplitude at a frequency close to the natural frequency and storing a liquid, the vibration can be suppressed as shown in FIG.

Further, as a result of the experiment, it is effective when the ratio of the effective mass M ₁ of the liquid W and the mass M of the building ₁ is set to M ₁ / M = 1/50 to 1/100 (6) It was possible to exert the vibration suppression effect. Here, if the effective mass is 1/100 or less, a sufficient vibration damping effect cannot be obtained, and if it is 1/50 or more, the liquid may cause the vibration effect to the contrary. Since it is necessary to perform this, it is better to set the ratio of M to M ₁ as in the above equation (6).

It should be noted that the shape of the tank 3 is not limited to the cylindrical shape as shown in the above-mentioned embodiment, but may be changed into various shapes such as a plane quadrangle, a sphere, and a plane ellipse depending on the installation conditions. In this case, the Hausner's theory may be applied to set the vibration period and the mass based on an equation corresponding to the shape.

"Effects of the Invention" As described above, the present invention has a configuration in which a tank provided at a required position of a building stores a liquid that vibrates with a phase difference in the same cycle as the building and vibrates the liquid. In order to suppress the vibration of the building, it is possible to obtain the vibration suppressing effect against earthquakes and winds. Further, when the liquid tries to flow in the circumferential direction in the tank against the vibration caused by the swinging rotation of the building, the adjusting member acts as a resistance to generate a turbulent flow in the tank and suppress the vibration. Therefore, the vibration accompanying the swinging rotation of the building can also be suppressed. Further, if the water supply tank or fire protection water tank provided in the building is used as the vibration suppression tank, it is not necessary to install the tank specially, and there is an advantageous effect in terms of equipment cost. Further, in claim 2, a plurality of adjusting members are provided at the bottom of the tank so as to project from the inner surface of the tank, and the adjusting member connects the lower tank and the upper tank. With these projections, it is possible to effectively suppress the vibration of the liquid, and it is possible to reliably support the load of the liquid in the tanks stacked on the upper part and the inside thereof from below.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention. FIG. 1 is an elevation view of a building equipped with a vibration suppressing device, FIG. 2 is a plan view of a tank, and FIG. FIG. 4 is a longitudinal sectional view of a tank, FIG. 4 is a vibration model of a building, FIG. 5 is a displacement response magnification diagram of the device of the present invention, FIG. 6 is a displacement response magnification diagram in the case of an empty tank, and FIG. FIG. 8 is a sectional view of a second embodiment of the invention, and FIG. 8 is a sectional view taken along the line AA ′ of FIG. W: Liquid, 1 ... Building, 2 ... Support stand, 3 ... Tank, 3a, 3b, 3c ... Adjusting member.

Claims (2)

[Claims] 1. A building is provided with a tank for storing a liquid, and the liquid in the tank vibrates between side walls of the tank at a natural vibration cycle that is the same as a natural vibration cycle of the building. The tank has a space that allows the vibration of the liquid above the liquid surface of the liquid in a stationary state,
A plurality of adjusting members are provided so as to project from the inner surface of the tank, and the adjusting members are arranged substantially in the radial direction of the tank in a plan view and arranged along the inner circumference of the tank. Characteristic building vibration control device. 2. A building is provided with a plurality of tanks for storing a liquid, the liquid in each of the tanks having a natural vibration cycle which is the same as a natural vibration cycle between the side walls of the tanks. Each tank has a space above the liquid surface of the liquid in a stationary state that allows vibration of the liquid, and a plurality of adjusting members are provided at the bottom of the tank so as to project from the inner surface of the tank. The vibration suppressing device for a building, wherein the adjusting member is provided by connecting a tank located on a lower side and a tank located on an upper side thereof.