JP2729231B2 - Vibration suppression device for structures - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration suppression device for a structure, which suppresses a vibration caused in the structure by an earthquake, wind, or the like.

`` Conventional technology and its problems '' In recent years, architectural and civil engineering structures have become larger, diversified in form due to factors such as the development of high-strength materials, advances in machining technology, and the development of structural analysis technology using computers. The structure is lightweight and flexible with respect to external forces. And, in such a lightweight and flexible structure, its natural frequency is low and the internal vibration damping tends to be small, so that various vibrations which cannot be expected due to the influence of an external force such as an earthquake or a wind are generated. 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 unnecessary unease to humans living inside the structure, There was even a risk of giving a stress exceeding the allowable range to the skeleton.

In view of this, the inventor of the present application disclosed in Japanese Patent Application No. 60-241045 that a predetermined position of a structure vibrates at the same period as the inherent vibration period of the structure and with a required phase difference. A tank for storing a liquid is provided, and a vibration suppressing device capable of suppressing the vibration of the structure by the vibration of the liquid is proposed to solve the above-described problem.

Incidentally, a structure such as a normal building has a rectangular cross-sectional shape, and therefore, its natural period often differs depending on the vibration direction of the structure. In particular, as described above, since the vibration characteristics of the structure are becoming complicated with the diversification of the types of the structure, it has been desired to realize a vibration suppression device that can flexibly cope with a plurality of vibration periods.

In view of the above circumstances, the present invention has been made by developing the vibration suppression device proposed by the inventor of the present invention, and is capable of effectively attenuating the vibration of a structure having a plurality of natural vibration periods. The purpose is to provide a suppression device.

Means for Solving the Problems Accordingly, the present invention provides a tank at a predetermined position of a structure, and the inside of the tank is at least different from each other by partition walls extending in a vertical direction and a horizontal direction. Divided into a plurality of chambers having two inner diameters, and further inside each of these chambers, at the same vibration period as the natural vibration period of the structure in a direction along the plurality of inner diameters,
In addition, the above problem is solved by configuring a vibration suppressing device for a structure in which a liquid that vibrates with the natural vibration of the structure and a required phase difference is stored.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 to 3 are views showing a first example of a vibration suppressing device for explaining a basic technical idea of the present invention. In the figure, reference numeral 1 denotes a vibration suppression device, and the vibration suppression device 1 is installed on the roof of a high-rise building (structure) 2 which is considered to be most effective against vibrations caused by wind. The building 2 is, for example, a building whose cross-sectional shape is formed in a substantially rectangular shape and has an excellent natural vibration period in two directions on a plane.

The vibration suppressing device 1 includes a support 3 having a laminated structure of an elastic body such as rubber and a steel plate, a tank 4 mounted on the support 3, and a liquid 5 stored in the tank 1. It is roughly constituted from.

The tank 4 is a rectangular cylindrical tank for storing drinking water, fire prevention water, cooling and heating equipment water, and the like of the building 2, and has a structure in which an upper portion is opened. More specifically, the tank 4 is formed to have a substantially rectangular cross-sectional shape, and is provided with partition walls 6, 6,. Are divided into a plurality of rooms 7, 7,... These rooms 7, ...
The cross-sectional shapes are classified into two types of chambers 7a, 7b,... Whose inner diameters along the long side direction and the short side direction are respectively
a ₁ and b ₁ (a ₁ > b ₁ ) and a ₂ and b ₂ (a ₂ > b ₂ ).
Further, each of the chambers 7a and 7b has a specific gravity and an inner diameter of the chamber.
Liquid surface height according to a ₁ , b ₁ and a ₂ , b ₂ (H ₁ , H _{2 in} FIG. ₂ )
The liquids 5, 5, and 5 are appropriately adjusted so that the vibration cycle along the long side direction and the short side direction becomes the same vibration cycle as the natural vibration cycle of the building 2 in the same direction. … Are stored respectively. The chambers 7a, 7 are arranged such that the total mass of the liquids 5, 5, ... is within the range of 1/50 to 1/100 of the mass of the building.
The amount stored in b has been adjusted.

It is preferable that the tank 4 and the partition walls 6,... Are formed of a material (for example, made of plastic) that does not corrode even in long-term use. Similarly, the liquid 5 is a viscous liquid ( (Eg, oil). However, the materials of the tank 4, the partition walls 6,... And the liquid 5 may be appropriately determined depending on construction conditions and the like, and are not limited to the above-described materials.

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

A vibration system including the building 2 and the vibration suppression device 1 can be approximated and simplified to a vibration model as shown in FIG. In the following description, one chamber 7a in the tank 4 will be described.
(Or 7b) This is a discussion on only the vibration in the long side direction or the short side direction. However, even when the vibrations in the long side direction and the short side direction are simultaneously generated, or when the entire tank 4 vibrates, Clearly, the discussion below is applicable.

The vibration model, the spring 8A and the damping factor h ₀ of the spring constant K ₀
Through the dashpot 10A, the mass M vibration system object 9A is supported for ₀ A (vibration model of a building 2), via the spring 8B and dashpot 10B attenuation factor h ₁ of the spring constant K ₁ Te, the vibration system B which objects 9B of mass M ₁ is supported (chamber 7a
(Or a vibration model of the liquid 5 in 7b) is connected in series.

In such a vibration model, when the vibration system A starts to vibrate in the long side direction or the short side direction of the chamber 7a (7b) due to an external force such as an earthquake or a wind applied to the object 9A, the vibration system B becomes 1/4. Since oscillation starts with a phase delay of the period,
By matching the vibration periods of the vibration systems A and B, the vibration of the vibration system A can be suppressed.

Here, since the mass of the object 9B is about 2% of the mass of the object 9A, the natural vibration period T ₀ of the building 2 is substantially unique by the mass M ₀ and the spring constant K ₀ determined from the viewpoint of structural design. Is determined. Therefore, the vibration period of the vibration suppressing device 1, that is, the vibration period T ₁ of the liquid 5 stored in each of the chambers 7 a (7 b) matches the natural vibration period T ₀ of the building 2 so that the vibration period T ₁ coincides with the natural vibration period T ₀ of the building 2. What is necessary is just to set the size and capacity of (7b) and the storage amount of the liquid 5. The behavior of the liquid 5 stored in the chamber 7a (7b) can be analyzed as follows.

The relationship between the j-th natural oscillation period T _j of sloshing and the j-th natural circular frequency ω _j is represented by the following equation.

T _j = 2π / ω _j (1) Then, in the above equation (1), if H is the storage depth of the liquid and g is the gravitational acceleration, ω _j is an amount given by the following equation.

Further, k _j in the above equation (2) is given by the following equation, where a is the width of the chamber 7a (7b).

k _j = (2j−1) π / a (3) Accordingly, the natural oscillation period T _j can be obtained for the sloshing from the equations (1) to (3) shown above. For this purpose, the natural oscillation period T in the first-order sloshing may be used. This is represented by the following equation.

As described above, according to the vibration suppressing device 1,
Vibration excited in the building 2 by an external force such as an earthquake or wind can be suppressed. In particular, in the vibration suppressing device 1, the vibration periods of the liquids 5, 5,... In the long side direction and the short side direction of each of the chambers 7a, 7b,. So each room 7
The vibrations in two directions having different natural vibration periods can be effectively suppressed by a and 7b. Therefore, even in the case of the actual vibration in which these vibrations are complicatedly superposed, the vibration can be effectively suppressed.

The details of such a vibration suppression device are not limited to the first example, and various modifications are possible. Hereinafter, a second example of the vibration suppression device will be described with reference to the drawings.

FIG. 5 is a view showing a second example of the vibration suppressing device for explaining the basic technical idea of the present invention. In the following description, the same components as those in the first example will be denoted by the same reference numerals, and description thereof will be omitted. In this example, the tank 4 of the vibration suppression device 1 is divided into a plurality of chambers 7a, 7b and 7c having three types of cross-sectional shapes. And in each of these chambers 7a, 7b and 7c, ...
The liquids 5, 5,... Are stored under such a condition that the vibration cycle along the major axis direction and the minor axis direction is the same as the natural oscillation cycle of the building 2 in the same direction.

Therefore, in this example, similarly to the first example, the chambers 7a and 7b
The vibration of the building 2 in the major axis direction and the minor axis direction of the building 2 is effectively attenuated by these chambers 7a, 7b and 7c, respectively, and an effective vibration suppressing effect can be obtained.

Here, an embodiment of the structural vibration suppressing device of the present invention having the above-described basic technical idea will be described below. As shown in FIG. 6, a vibration suppressing device 1 according to an embodiment of the present invention has a closed structure by closing an upper portion of a tank 4 in the first example, and further has partitions 6 ', 6 extending horizontally. ′, The chambers 7a, 7b in the first example are divided horizontally to form a large number of small chambers 7d,. Also in this device 1, the same operation and effects as those of the first and second examples can be obtained, and furthermore, a larger number of chambers can be formed, so that fine setting is possible.

In the above embodiment, the shape and the number of the tanks 4 and the number of the chambers 7a,... Are arbitrary, and may be appropriately determined in consideration of the shape and the vibration property of the building 2.

[Effects of the Invention] As described above in detail, according to the present invention, a tank is provided at a predetermined position of a structure, and the inside of the tank is formed by partition walls extending in a vertical direction and a horizontal direction. Each of the chambers is divided into a plurality of chambers having at least two different inner diameters, and inside each of these chambers, at the same vibration period as the natural vibration period of the structure in a direction along the plurality of inner diameters, and Since we have constructed a structure vibration suppression device that stores liquid that vibrates with the natural vibration of the structure and the required phase difference respectively,
Vibrations in directions having different natural vibration periods can be effectively suppressed by each of these chambers. Therefore, vibrations can be effectively suppressed even in actual vibration in which they are complicatedly superimposed. Therefore, according to the present invention, it is possible to realize a vibration suppressing device capable of effectively attenuating the vibration of a structure having a plurality of natural vibration periods.

[Brief description of the drawings]

FIGS. 1 to 3 are views showing a first example of a structure vibration suppressing device for explaining a basic technical idea of the present invention, wherein FIG. 1 is a plan view and FIG. Is II- in Fig. 1.
FIG. 3 is a schematic view showing a state of being installed on the roof of a building, FIG. 4 is a schematic view showing a structure and a vibration model of a vibration suppressing device, and FIG. FIG. 6 is a plan view showing a structure vibration suppressing device according to a second example for explaining the basic technical idea of the present invention. FIG. 6 is a cross-sectional view showing the structure vibration suppressing device according to an embodiment of the present invention. FIG. 1 ... vibration suppression device, 2 ... building (structure), 4 ...
Tank, 5 ... Liquid, 6, 6 '... Partition wall, 7 ... Chamber.

Claims (1)

(57) [Claims] A tank is provided at a predetermined position on a structure, and the inside of the tank is formed by partitions extending in a vertical direction and a horizontal direction. Each of the chambers has the same vibration period as the natural vibration period of the structure in the direction along the plurality of inner diameters, and the required natural vibrations of the structure in the respective directions. A vibration suppressing device for a structure, wherein a liquid that vibrates with a phase difference is stored.