JPS6340064A - Vibration damper for building - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application] The present invention relates to a vibration suppression device that suppresses vibrations caused in buildings by earthquakes, wind, etc.

"Conventional technology and its problems" Due to factors such as the development of high-strength materials, progress in construction technology, and development of structural analysis technology using computers, buildings in recent years have become larger, more diverse in form, and lighter. As technology advances, structures are becoming more flexible. In addition, such lightweight and flexible buildings tend to have low natural frequencies and low vibration damping, and as a result, various unpredictable vibrations occur due to the influence of external aerodynamic forces, especially those caused by wind. there's a possibility that.

For this reason, it is conceivable to take aerodynamic measures to the external shape of a building with the aim of cutting off this type of vibration source. However, it is difficult to rely solely on aerodynamic measures.

Therefore, in the specification of Japanese Patent Application No. 60-241045, the present inventor proposed the following method:
We have proposed a vibration suppression device that is equipped with a tank that stores a liquid that is 11IJ, and can suppress the horizontal shaking of a building by the vibration of this liquid, thereby solving the above problem.

However, the vibrations that act on a building include a pond of horizontal shaking,
If the center of gravity of the building is misaligned with the center of gravity, the building may undergo rotational movement due to the aerodynamic force exerted by the lice, that is, the building may swing.

In view of the above-mentioned problems, the present invention has been developed by developing the vibration suppression device previously proposed by the inventor of the present invention.
It is also an object of the present invention to provide a device that can suppress both vibrations caused by swing rotation.

``Means for Solving the Problems'' In order to solve the problems mentioned above, the present invention provides a structure in which vibration frequency is the same as that unique to the building, and the vibration frequency is the same as that unique to the building. A tank is provided for storing a liquid that vibrates with a vibration period and a phase difference, and an adjustment member is provided on the inner surface of the tank to adjust the attenuation of the vibration of the liquid.

"Effect" When vibrations are applied to a building due to an earthquake or wind, etc., the liquid stored in the tank is in the same phase as the vibration period of the building, and is in phase with it. : When vibrations occur in the state of the earth, and vibrations are suppressed mainly from the horizontal shaking of the building, when vibrations occur due to swinging of the building due to earthquakes or wind, the rotation of the swinging head causes damage to the circumference of the tank. The liquid moving in the direction is resisted by the adjustment member, creating turbulent flow and suppressing the swinging rotation.

"Example" Figures 1 to 3 show a building such as a high-rise building equipped with a vibration suppression device according to an example of the present invention. A support base 2 made of a laminated structure of an elastic body such as rubber and a steel plate is installed on the rooftop, which is said to be most effective against unnatural vibrations.A tank 3 with a vibration suppressing effect is installed on the support base 2 It is now f two-groove formation.

The tank 3 is a cylindrical tank for storing drinking water or fire prevention water for the building 1, and has an open top structure, as shown in FIGS. 2 and 3. By storing the liquid W under such conditions that the external dimensions are the same and the vibration period is the same as that of the building I, vibrations of the building caused by wind or the like are suppressed. A plurality of adjustment ribs (adjustment members) 3a are formed around the bottom of the tank 3 and are in contact with the side wall of the tank 3. These adjustment ribs 3a are formed at a height such that they are submerged in the liquid W stored in the tank 3, and furthermore, they are spaced apart from each other by a predetermined distance along the circumferential direction of the tank 3, and each of them is located on the bottom surface of the tank 3. It is formed to extend radially from the center. Further, on the inside of the bottom surface of the tank 3, an adjustment rib (adjustment member) having the same size as the adjustment rib 3a is provided.
3b are formed to extend radially from the center of the tank 3, and adjustment ribs (adjustment members) 3c are also formed at the center of the bottom surface of the tank 3 and extend radially.

The liquid W in the tank 3 is stored at a depth such that the vibration period is the same as that of the building l, thereby suppressing vibrations of the structure l caused by wind.

In addition, if the center of gravity of the building 1 and the point of caution are misaligned, and if a swing rotation occurs in the building 1, the liquid inside the tank will try to flow in the circumferential direction of the tank 3. In this case, the adjustment ribs 3a, 3b.

Since 3c acts as a flow resistance of the liquid, the liquid flows in the circumferential direction of the tank 3 with the same period as the oscillation period of the building 1 but out of phase, and the liquid also suppresses this oscillation rotation. .

Therefore, according to the vibration suppressing device of the above structure, buildings! It should be possible to suppress both vibrations centered on the swing of the structure and vibrations centered on the rotation of the head.

By the way, the liquid W stored in the tank 3 needs to vibrate at the same period as the period of the building l but out of position. Therefore, when using a tank 3 that is not equipped with adjustment members 3 a, 3 b, and 3 c, the vibration damping rate of the liquid W itself is small, so unless a liquid with a higher viscosity than water is used, the vibration will be increased. It may have the effect of However, in the structure of the present invention, no matter what kind of building it is applied to, the attenuation rate of the liquid itself stored in the tank 3 can be adjusted by adjusting the width, size, and number of the adjustment members 3a, 3b, and 3c. This means that the damping rate of the entire structure can be adjusted.

It is estimated that the width of each adjustment member should be set to about 5 cm for a tank with a diameter of about 30 m.

FIG. 7 shows a second embodiment of the present invention, and this embodiment has a multilayer structure in which a plurality of bottom walls 3d are formed in the tank 3 and the inside of the tank 3 is divided vertically into a plurality of small chambers 3e. In addition, each bottom wall 3e is supported by a plurality of column-shaped adjustment members 3F erected inside the tank.

In this embodiment, the attenuation of the stored liquid W is adjusted by the adjustment member 3f, and the adjustment member 3f supports the bottom wall 3F, so that the same effects as in the previous embodiment can be obtained in this embodiment as well. Can be done. Note that this embodiment has the feature that different types of liquid can be stored in each of the small chambers 3e of the tank 3, and by adjusting the volume and viscosity of the liquid stored in each small chamber 3e, the vibration suppressing effect can be improved. can be adjusted.

Note that the following describes the analysis performed in Japanese Patent Application No. 60-241045 7-': BJ analysis of building 1 and tank.

First: J1! If the tank is analyzed, this tank and the building 1 exhibit vibration characteristics similar to the vibration model shown in FIG. 4.

The vibration model shown in Fig. 4 has a spring constant K. Spring 4A quality ff1M. When the object 5A is supported, the attenuation rate is B. A vibration system A (vibration model of I-dyed fabric) in which dashbots 6 and 8 of
It consists of a vibration system B (vibration model in the tank) to which a Danyu pot 6B with a damping rate is added.

In such a vibration model, when vibration system A starts to vibrate due to an external force applied to object 4A, vibration system B starts to vibrate with a phase difference of 174 cycles.
By matching the vibration periods of the vibration systems A and B, the vibrations of the vibration system A can be suppressed.

Here, the vibration period of the vibration system is and the vibration period T of the construct l.

is the quality ff1M determined from the viewpoint of structural design. , and spring constant K. Since it is uniquely determined by, the vibration period T of the liquid W stored in the tank 3 is T. The dimensions and capacity of the tank 3 are set to match the two.

That is, according to Housner's theory, which holds regarding the behavior of the liquid stored in the tank, the effective mass of free water M, which is movable in the tank 3 as shown in the illustrated example (the quality that acts as a vibrating body), is as follows: According to formula (2), H...Distance from the bottom of tank 3 to the water surface R...
... Radius M of the tank 3 ... Mass of the liquid actually stored in the tank 3 Also, the natural vibration ω (so-called natural frequency of sloshing) of the stored liquid W is expressed as the following (3 ) According to the formula, nJ
From the atE natural vibration dispersion ω, find the vibration period T as shown in equation (4) below.

2π T-□ ... ... Equation (4) For example, if R = I5m H = 2m M = 1414 t (M = 812t from equation 2) is substituted, T = 11.7 Second and t.

Then, between the vibration period of the liquid in the tank obtained by the above formula and the vibration period IgITo of the building, T o ” T
, . . . . . . . Set the dimensions and storage amount of the tank 3 so that equation (5) holds true.

In addition, as a result of experiments on the displacement response magnification due to vibration using a vibration table, characteristics as shown in FIGS. 5 and 6 were obtained. Figure 5 shows the results of an experiment conducted with liquid (water) stored in a tank, and Figure 6 shows the tank.

The results of an experiment conducted in an empty state are shown.

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

Furthermore, as a result of the experiment, the ratio between the effective mass MI of the liquid W and the mass M of the building 1 is M + / M = 1 / 50 ~ l / 100.
・・・・・・・・・・When setting according to formula (6), it was possible to effectively exhibit the vibration suppressing effect. Here, if the effective mass layer is less than 1/100, sufficient vibration damping effect cannot be obtained,
If it is 1750 or more, the liquid may adversely cause the vibration effect, so it is necessary to perform the structural design of the building again. Therefore, the ratio of M and M is set as in the above equation (6). It's better.

Furthermore, if it is necessary to keep the liquid in the tank in a fixed state (in a tightly packed state in a closed tank) due to various factors, instead of the above formula (2), the following is adopted: The tank volume and other various numerical values may be determined from the results obtained by this equation (2).

The shape of the tank 3 is not limited to the cylindrical shape shown in the above embodiment, but may be changed to various shapes depending on the installation conditions, such as a square planar shape, a spherical shape, and a planar elliptical shape. In this case, it is sufficient to apply Hausner's theory and set the vibration period and mass based on a formula depending on the shape.

"Effects of the Invention" As explained above, the present invention has a structure in which a liquid that vibrates with the same period as the building and a phase difference is stored in a tank provided at a predetermined position of a building. In order to suppress the vibration of buildings, it is possible to obtain vibration suppression effects against earthquakes and wind.

Furthermore, when the liquid tries to flow in the circumferential direction within the tank due to vibrations caused by the swinging of the building, the adjustment member acts as a resistance, creating turbulent flow within the tank and suppressing serious vibrations. Therefore, vibrations caused by swinging and rotation of the building can also be suppressed. Further, if a water supply tank or a fire prevention water tank provided in a building is used as a vibration suppression tank, there is no need to specially install a tank, which is advantageous in terms of equipment costs.

[Brief explanation of the drawing]

1 to 3 show one embodiment of the present invention, in which FIG. 1 is an elevation view of a building equipped with a vibration suppression device, and FIG.
The figure is a plan view of the tank, Figure 3 is a vertical cross-sectional view of the tank, and Figure 4 is a longitudinal sectional view of the tank.
The figure is a vibration model diagram of a building, Figure 5 is a displacement response magnification diagram of the device of the present invention, Figure 6 is a displacement response magnification diagram for an empty tank, and Figure 7 is a cross section of the second embodiment of the present invention. 8 is a sectional view taken along the line AA' in FIG. 7. W...Liquid, 1...Building, 2...Support stand,
3...tank, 3a, 3b, 3c...adjustment members.

Claims (1)

[Claims] A tank is provided at a predetermined position of the building, and inside this tank there is a liquid that vibrates at the same vibration period as the vibration period unique to the building and with a phase difference from the vibration unique to the building. 1. A vibration suppressing device for a building, wherein a plurality of adjusting members for adjusting attenuation of the liquid are stored inside the tank and protrude from an inner surface of the tank.