JPH0756186B2 - Vibration suppression device for structures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention relates to vibration of structures installed in these structures in order to suppress vibrations excited in buildings and civil engineering structures due to earthquakes and winds. The present invention relates to a suppression device.

"Conventional technology and its problems" In recent years, construction and civil engineering structures have become larger and diversified in form 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. In addition to being lightweight, it has a structure that is highly flexible against external forces. In such a lightweight and flexible structure, its natural frequency is low and its internal vibration damping tends to be small, so that various unexpected vibrations may occur due to the influence of external forces such as earthquakes and winds. Can occur.

In particular, as described above, as the size of the structure increases, the amplitude of the vibration excited by the external force also increases, and this vibration gives an uncomfortable feeling to the person living inside the structure, and There was even a fear of applying a stress exceeding the permissible range to the frame.

Therefore, the inventor of the present application has filed Japanese Patent Application No. 60-241045
-101764) in the specification, at a predetermined position of the structure,
Vibration capable of suppressing the vibration of the structure due to the vibration of the liquid by providing a storage tank for storing a liquid vibrating in the same cycle as the unique vibration cycle of the structure and with a required phase difference A suppression device is proposed to solve the above problems.

One example of the vibration suppressing device shown in the above-mentioned specification has a structure in which a cylindrical storage tank is provided on the roof of a structure and liquid is stored in this storage tank. By the way, the effective mass of the liquid stored in this storage tank is preferably 1/50 to 1/100 of the mass of the structure in consideration of the vibration damping effect of the vibration suppressing device and the structural design of the structure. However, it takes a lot of work to install the vibration suppression device of such a scale on the structure, and the installation place is limited to a place such as a rooftop where a large space can be secured, so some measures are required. It was

In view of the above problems, the present invention has been made by developing the vibration suppression device previously proposed by the inventor of the present application, and is easy to install, move, remove, and the like, and its installation location is not selected. The purpose is to provide a vibration suppression device.

"Means for Solving Problems" The present invention relates to a vibration suppressing device for a structure, which is installed in a structure and suppresses vibration excited in the structure by an external force such as an earthquake or wind. The device comprises a plurality of box-shaped tanks that can be continuously arranged in the vertical direction and the horizontal direction, and a liquid that is stored inside these tanks and vibrates at the same natural vibration cycle as the natural vibration cycle of the structure, Each of the tanks is characterized by having a space above the liquid surface of the liquid in a stationary state, which allows vibration of the liquid.

[Examples] Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a structure vibration suppressing apparatus according to an embodiment of the present invention. In the figure, reference numeral 1 is a vibration suppressing device, and the vibration suppressing device 1 is a building or civil engineering structure S.
It is installed at an arbitrary position inside (on the floor slab 2 of the structure S in the illustrated example).

The vibration suppressing device 1 includes a plurality of tanks 4, 4, ...
, And the liquids 5, 5, ... Stored in the tanks 4, 4, ... Under the condition that the natural vibration period is the same as the natural vibration period of the structure S. More specifically, the liquid 5 is the vertical direction of the tank 4 (X direction in the figure).
Is the same as the natural vibration cycle of the structure S in the X direction, and the horizontal vibration cycle of the tank 4 (Y direction in the drawing) is the same as the natural vibration cycle of the structure S in the Y direction. Thus, it is stored in the tank 4. Then, the vibration suppressing device 1 includes the liquids 5, 5, in the tanks 4, 4 ,.
The total mass of all ... is 1/50 of the mass of the structure S
It is configured to be within the range of 1/100.

Further, each of the tanks 4 has the liquid 5 in a stationary state.
There is a space above the liquid surface to allow the vibration of the liquid 5, and these tanks 4 are provided with scaled peep windows 6 formed on one side surface thereof with a transparent material such as glass. A liquid supply hose 7 whose tip extends to the bottom of the tank 4 is also provided. This hose 7
The base end portion is joined to one hose and is connected to a liquid supply unit (not shown). Thereby, the storage amount of the liquid 5 stored in the tank 4 can be finely adjusted after the vibration suppressing device 1 is installed, and at the same time, the respective tanks 4, 4, ...
The stored amounts of the liquids 5, 5, ... Further, the inner surface of the side wall of the tank 4 is formed into a concave-convex surface, which makes it possible to adjust the vibration damping rate of the liquid 5 due to the increase in the frictional force between the liquid 5 and the inner surface of the tank 4.

It should be noted that the tank 4 does not decay even after long-term use. It is preferable that the liquid 5 is made of a material (for example, plastic) that is not protected, and similarly, the liquid 5 is preferably a viscous liquid (for example, oil) that hardly evaporates even after long-term use. However, the materials of the tank 4 and the liquid 5 may be appropriately determined depending on the construction conditions and the like, and are not limited to the above materials. Further, the vibration suppressing device 1 is preferably installed on a support base having a laminated structure of an elastic body such as rubber and a steel plate.

Next, the operation of the vibration suppressing device 1 having the above configuration will be described.

The vibration system including the structure S and the vibration suppression device 1 has a second
The vibration model can be approximated and simplified as shown in the figure. This vibration model includes a vibration system A (a vibration model of a structure S) in which an object 9A having a mass M ₀ is supported via a spring 8A having a spring constant K ₀ and a dashpot 10A having a damping rate h ₀ ,
Spring 8B with spring constant K ₁ and dashpot 10B with damping rate h ₁
Is a model in which a vibration system B (a vibration model of the liquid 5 in the vibration suppression device 1) in which the object 9B having a mass M ₁ is supported is connected in series via the.

Here, as described above, the vibration suppressing device 1 is composed of a plurality of tanks 4, 4, ... And the liquids 5, 5, ... Stored in these tanks 4, 4 ,. Four
Since the natural vibration period of the liquid 5 stored therein matches the natural vibration period of the structure S, respectively,
5, ... vibrate together. Therefore, as described above, there is no problem even if the vibration suppressing device 1 is approximated by one vibration system B.

In such a vibration model, when the vibration system A starts to vibrate due to an external force such as an earthquake or wind applied to the object 9A, the vibration system B starts to vibrate with a phase delay of 1/4 cycle. By matching the natural vibration periods of A and B, the vibration of the vibration system A can be suppressed.

Here, since the object 9B has a mass of about 2% of the object 9A,
The natural vibration period T ₀ of the structure S is almost uniquely determined by the mass M ₀ and the spring constant K ₀ determined from the viewpoint of structural design. Therefore, the natural vibration cycle of the vibration suppressing device 1, that is, the natural vibration cycle T ₁ of the liquid 5 stored in each tank 4 matches the natural vibration cycle T ₀ of the structure S so that the natural vibration cycle T ₁ of the tank 4 matches the natural vibration cycle T ₀ of the structure S. The dimensions, the volume, and the storage amount of the liquid 5 may be set. The behavior of the liquid 5 stored in the tank 4 can be analyzed as follows.

The relationship between the jth natural frequency Tj of sloshing and the jth natural circular frequency ωj is expressed by the following equation.

Tj = 2π / ωj (1) Then, in the equation (1), H is the storage depth of the liquid,
If g is the gravitational acceleration, then ωj is an amount given by the following equation.

Further, kj in the equation (2) is 2a when the width of the tank 4 is
Then, it is given by the following equation.

kj = (2j-1) π / 2a (3) Therefore, the natural vibration period Tj of sloshing can be obtained from the above equations (1) to (3), and especially for suppressing the vibration described above. May use the natural vibration period in the first-order sloshing.

As described above, according to the vibration suppressing device 1 of the present embodiment, it is possible to suppress the vibration excited in the structure S by an external force such as an earthquake or wind. Here, the vibration suppressing device 1 includes a plurality of unitized tanks 4, 4, ... And liquids 5, 5, ... Stored in these tanks 4, 4 ,.
Since each of the tanks 4, 4, ... Is carried out for each of the tanks 4, 4, ..., each work of installing, moving, removing, etc. of the apparatus 1 is difficult. It will be easy. The arrangement method of the tanks 4, 4, ... Is not particularly limited either, and the total mass of the liquids 5, 5, ... Stored in the tanks 4, 4, ... Is 1 / M of the mass of the structure S. 50 ~
Since it is only necessary to arrange the structure S in a number within the range of 1/100, flexible arrangement is possible, and the installation place is not limited. Therefore, according to this embodiment, it is possible to realize a structure vibration suppressing device that facilitates work such as installation, movement, and removal, and that does not select the installation location.

The results of a simulation experiment conducted by the inventor of the present application will be shown below to verify the vibration damping effect of the vibration suppressing device 1 of the present invention. As an experimental system, as shown in FIG. 3, a five-layer model simulated structure S (mass M ₀ = 400 kg × 5
Vibration suppression device 1 of the present invention (total mass M _{1 of} liquid 5 = 52 kg, primary natural period T _{1 on} the roof of a layer, first natural period T ₀ = 0.41 seconds)
(= 0.41 seconds). Displacement of the simulated structure S fourth layer in the case where the vibration suppressing device 1 is not provided when a random wave (EL-CENTRO-NS wave) is applied to such an experimental system is shown in FIG. FIG. 5 shows the displacement of the fourth layer of the simulated structure S in the case where there is. As can be seen from the illustrated results, it can be understood that the vibration suppressing device 1 suppresses the vibration of the simulated structure S.

Furthermore, as a result of the simulation, the total effective mass of the liquid
The ratio of M ₁ and the mass M ₀ of the structure S, is set to _{M 1 / M 0 = 1 /} 50~1 / 100 ...... (4), turned out to be exerted effective vibration suppression effect did. That is, the total effective mass M ₁ is the mass of the structure.
At 1/100 or less of M ₀ , sufficient damping effect cannot be obtained, and at 1/50 or more, the influence of the mass of liquid on the structural design of the structure becomes large, and the structural design In some cases, it is necessary to set the ratio as in the formula (4).

The structure vibration suppression device 1 according to the present invention is not limited to the above-described embodiment. As an example, the vibration suppression device 1 is not only installed on the floor of the structure S as in the above-described embodiment, but is also installed by being hung from the lower surface of the floor slab 2, that is, the ceiling as shown in FIG. 6, for example. It may be installed, and in combination with its good transportability, it may be installed in any space in the structure S. Further, the shape of the tank 4 may be changed to various shapes such as a cylindrical shape, a spherical shape, and a plane elliptical shape depending on the shape of the structure S and the installation conditions. In this case, the theory may be appropriately changed, and the dimensions of the tank, the storage depth of the liquid, and the like may be set based on the formula corresponding to the shape. Further, by appropriately disposing a partition plate or the like in the tank 4 to have a wave-dissipating effect, it is possible to adjust the vibration damping rate due to the viscous resistance. When the tank 4 is made of a steel plate, the durability of the tank 4 itself can be increased by mixing a rust preventive agent in the liquid 5.

"Effects of the Invention" As described in detail above, the vibration suppressing device for a structure according to the present invention has a plurality of unitized tanks and the same natural vibration period as the structure, which is stored in these tanks. Since it is composed of a liquid that vibrates with the natural vibration period of the structure and with the natural vibration of this structure and a required phase difference, each work such as installation, movement, and removal of the device is performed for each tank. Therefore, each work such as installation, movement, and removal of the device becomes very easy. In addition, since the method of arranging each of the tanks is not particularly limited, it is possible to arrange with a high degree of flexibility, and the installation location is not limited. Therefore, according to the present invention, it is possible to realize a vibration suppressing device for a structure, in which work such as installation, movement, and removal is easy, and the installation place is not selected.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state where a structure vibration suppressing device according to an embodiment of the present invention is installed in a structure, and FIG. 2 is a schematic view showing a vibration model of the structure and the vibration suppressing device. Third
FIG. 5 is a schematic diagram showing an outline of an experimental system of a simulation experiment, FIG. 4 is a diagram showing a vibration state of a simulated structure which is not equipped with a structure vibration suppressing device according to an embodiment of the present invention, and FIG. FIG. 6 is a diagram showing a vibration situation of a simulated structure provided with a vibration suppressing device, and FIG. 6 is a sectional view showing another embodiment of the present invention. S: Structure, 1 ... Vibration suppressor, 4 ... Tank, 5
……liquid.

Claims (1)

[Claims] 1. A vibration suppressing device for a structure, which is installed in a structure and suppresses a vibration excited in the structure by an external force such as an earthquake or a wind, the vibration suppressing device comprising a vertical direction and a horizontal direction. A plurality of box-shaped tanks that can be continuously connected to each other and a liquid that is stored inside these tanks and that vibrates in the same natural vibration cycle as the natural vibration cycle of the structure. A vibration suppressing device for a structure, wherein a space for allowing vibration of the liquid is provided above the liquid surface of the liquid.