JPH03137368A - Vibration isolating device for structure - Google Patents

Abstract

PURPOSE:To suppress vibrations caused by external force such as earthquake, strong wind, etc. effectively by furnishing a water tank to store liquid, a stay to support the center of the tank bottom, and a plurality of actuators for supporting the tank bottom at its two ends with possibility of moving vertically. CONSTITUTION:A prop 2 in the form of a truncated cone supporting an overhead water tank 3 by its undersurface is faced upward and fixed in the center of the upper bottom surface 2a by a spherical pin 8, whose tip is in contact with the center of the bottom surface 3a of the water tank 3, and the lower bottom surface 2b is tightly fastened onto the floor surface E. The water tank 3 is filled with water 9 to the half, and sensors 6... for vibration measurement are installed in the longitudinal center of upper bottom surface 3b, and actuators 4... are coupled in the longitudinal center of the bottom surface 3a. The actuators 4 are installed vertically at the bottom surface E, and their tops are coupled in the longitudinal center of the bottom surface 3a of the water tank 3, while their lower ends are coupled with the bottom surface E. Thereby the device can be simplified.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a vibration suppression device for structures that can effectively suppress vibrations caused in structures by external forces such as earthquakes and strong winds. .

[Conventional technology] In recent years, architectural and civil engineering structures have become increasingly larger, more diverse, and lighter due to factors such as the development of high-strength materials, dramatic advances in construction technology, and advances in structural analysis technology using computers. As technology advances, structures are becoming more flexible in response to external forces. In such a light and flexible structure, the natural frequency tends to be low and the vibration damping tends to be low.

Therefore, when an external force such as an earthquake or strong wind acts on the structure, various unexpected vibrations may occur.

For this reason, it is conceivable to take aerodynamic measures to the external shape of the structure in order to cut off these sources of vibration, but the external shape of the structure has various restrictions from a functional and design perspective. , it is difficult to rely solely on this aerodynamic measure.

Therefore, in order to suppress the above-mentioned vibrations, various vibration suppression methods have been proposed in which a water tank for storing liquid is provided at a required position of a structure, and the vibration of the structure can be suppressed by the vibration of this liquid. It is used in many structures. The following three methods are representative among these methods. The first method is to install a water tank at the required position of the structure, store a liquid that vibrates in the tank at the same period as the structure's natural vibration period, but with a phase difference. TLD that suppresses the vibration of structures using the reaction force generated by
(tuned liquid damper) method. A typical example of this method is the sloshing damper method.

The second method is to suspend the water tank at a desired position on the structure using wires, etc. so that it can vibrate in the direction you want to suppress the vibration of the structure, and the water tank vibrates like a pendulum, which allows the structure to move. This is a TMD (tuned mass damper) method that suppresses vibrations.

The third method is to attach the water tank to the required position on the structure so that it can vibrate in the direction you want to suppress the vibration of the structure.
This is an AMD (active mass damper) method that forcibly applies an external force to the tank using mechanical or magnetic force such as an actuator, moves the tank horizontally, and suppresses the vibration of the structure using the generated reaction force. .

[Problems to be Solved by the Invention] By the way, the above-mentioned 10) TLD method has the advantage that it is not necessary to apply energy from the outside, but the generated reaction force is relatively small and the unique period of the structure On the contrary, the longer the water is, the smaller the effective reaction force becomes, which has the disadvantage of requiring a larger aquarium. In addition, the second T
In the MD method, the unique period of the structure is long, and the period of the water washing tank is also long, so it is necessary to make the length of the wire, etc. for suspending the water tank sufficiently long. Therefore, there is a drawback that it becomes difficult to secure a three-dimensional space within the structure that is commensurate with the length of the wire, etc. Also, the third AM above
In the D method, the aquarium is moved horizontally by forcibly applying an external force to the aquarium, which has a structural drawback in that it requires a long-stroke sliding mechanism and a large driving force.

An object of the present invention is to provide a vibration suppressing device for structures that can effectively solve the above problems, simplify the entire device, and have a vibration suppressing effect superior to conventional systems. .

[Means for Solving the Problems] In order to solve the problem described in item 1, the present invention employs the following structure vibration suppression device. That is, it is a vibration suppression device for a structure that is installed at a predetermined position of a structure and can suppress vibrations excited in the structure due to external forces such as earthquakes and wind.

1. The vibration suppression device comprises a water tank for storing liquid, a column supporting the center of the bottom of the tank, and a plurality of actuators movably supporting both ends of the bottom of the tank in a downward direction. We are prepared.

[Operation] In this invention, when vibrations are excited in the structure due to external forces such as earthquakes or wind, the plurality of actuators are moved in the vertical direction, and the water tank is centered at the center of the bottom and both ends of the bottom are moved in a vertical plane. Move it up and down. This movement causes the center of gravity of the liquid in the tank to move horizontally outward, creating a reaction force.

Vibrations can be suppressed by this reaction force acting against vibrations centered on the horizontal shaking of the structure.

[Embodiment] FIGS. 1 to 7 are diagrams showing an embodiment of the present invention. In these figures, the symbol ■ indicates a vibration suppression device for a structure according to the present invention (hereinafter simply referred to as a vibration suppression device).
It is.

As shown in Figure 1, this vibration suppression device 1 is installed on the floor near the roof of high-rise building A, where it is assumed to be most effective against vibrations caused in high-rise building (structure) A by earthquakes and strong winds. The vibration suppression device I consists of a column 2, an elevated water tank (water tank) 3, an actuator 4.4, a control device 5, a sensor 6.6, and a sensor 7. That is.

The support column 2 supports the elevated water tank 3 from its lower surface, and serves as a fulcrum when the elevated water tank 3 vibrates. The shape is almost a truncated cone, and a pin 8 with a spherical tip is attached to the center of the upper bottom surface 2a facing upward.
b is fixed in close contact with the floor surface E. pin 8
is in contact with the center of the bottom surface 3a of the elevated water tank 3.

The elevated water tank 3 is an elongated box-shaped water tank with a rectangular cross section in the longitudinal direction, and water 9 is normally stored in this elevated water tank 3 by about half of its internal volume. . Sensors 6, 6 for measuring vibrations of the elevated water tank 3 are attached to the center of both longitudinal ends of the upper bottom surface 3b of the elevated water tank 3. Similarly, actuators 4.4 are connected to the centers of both ends of the bottom surface 3a in the longitudinal direction.

The actuator 4 is rod-shaped, the length of the central portion of which can be freely varied, and is installed substantially perpendicularly on the floor surface E. The upper end 4a of the actuator 4 is connected to the center of one longitudinal end of the bottom surface 3a of the elevated water tank 3, and is rotatable within a vertical plane that includes these actuators.

Further, the lower end portion 4b is connected to the floor surface E, and the upper end portion 4b is connected to the floor surface E.
It is rotatable within the same vertical plane as a.

On the other hand, a sensor 7 for measuring vibrations excited in the high-rise building A is attached to the rooftop IO of the high-rise building A.

The control device 5 is installed on the floor F''- and the vibration suppression device 1
It performs overall control, and has a control section I+, a drive section 12, and a computer I3 as its main components. The control unit 11 receives input from the sensor 6 and the sensor 7, and the computer 13.
The input/output of the drive unit 12 and the input/output of the drive unit 12 are performed in a unified and effective manner.

The drive unit 12 is for operating the actuators 4, 4 in the vertical direction according to the output from the control unit 11.

The computer 13 connects the sensor 6.6 and the sensor 7 to the control unit II.
The amplitude, phase, period, etc. of the vibration are calculated based on the information regarding the vibration transmitted to the controller 4.4, appropriate operating conditions for the actuator 4.4 are calculated, and the results of these calculations are fed back to the control unit 11.

Next, using the vibration suppression device 1 having the above configuration, the high-rise building A is
A method of suppressing vibrations excited by the vibration will be explained with reference to FIGS. 1 and 2.

Vibration control device lgaya” - high-rise building A installed nearby
When an earthquake acts on the high-rise building A, since the high-rise building A is a long-period structure with a long natural period, sinusoidal vibrations are excited in the high-rise building A due to long-period components included in the seismic motion.

The sensor 7 senses this vibration and transmits information regarding the vibration to the control unit 11. Upon receiving this information, the control section 11 starts up the drive section I2 and transmits the above information to the computer 13. The computer 13 calculates the magnitude, phase, natural period, etc. of the vibration of the earthquake based on this information, calculates the magnitude, phase, period, etc. of the vibration that are appropriate operating conditions for the actuator 4, and feeds it back to the control unit 11. . The control unit II is
The drive unit 12 is operated based on the calculation result, and the actuators 4 are operated in the vertical direction under appropriate operating conditions. In this case, the actuators 4.4 always operate in opposite directions. The vertical movement distance (stroke) of the actuator 4.4 is "1" when the elevated water tank 3 is tilted from the resting position and the water line reaches the bottom of the elevated water tank 3.
It is twice the downward movement distance. The elevated water tank 3 vibrates in a vertical plane using the pin 8 as a fulcrum according to the movement of the actuator 4.4, and a series of movements (a)-( b) - (a) - (c) - (a) -... are repeated periodically. Here, Fig. 2 (a) to (c) shows - (a): The resting position of the elevated water tank 3, (b): When the elevated water tank 3 is tilted by θ-X/L () from the resting position. Position, (C), θ in the opposite direction to (b) from the resting position of the elevated water tank 3
The position when tilted by -x/L is shown.

In addition, the symbols in the figure are as follows: 2L: Length in the longitudinal direction of the elevated water tank 3, d: Depth of the elevated water tank 3, d/2: Depth of the water 9 when stationary, 2X: Stroke of the actuator 4, GO : Center of gravity of the water 9 at rest, G: Center of gravity of the water 9 when the elevated water tank 3 is at its maximum inclination, r, horizontal movement distance of the center of gravity G of the water 9. Here, the elevated water tank 3 is θ-X/L from the resting position.
When the water 9 in the elevated water tank 3 is tilted by
move only. If the mass of water 9 is m, the generated reaction force is calculated by the following equation.

P=m・(d'r/dt2) d2r/dt': Acceleration of the movement of the center of gravity of the water 9 This reaction force is used as a control force for the vibration of the high-rise building A. The magnitude, phase, and period of this control force are calculated by the computer 13 so that this force works most effectively for vibration control of the high-rise building A.

The movements of the actuator 4.4 are constantly monitored by the sensor 6.6, and information regarding these operations is sent from time to time to the control unit II. The computer 13 recalculates and corrects the operating conditions of the actuator 4 based on this information.

FIG. 3 is a diagrammatic representation of the second control.

These series of movements are continued until the vibrations of the high-rise building A are damped within a certain limit.

Next, the results of a study to confirm the effectiveness of the vibration suppressing device I of the present invention will be explained with reference to FIGS. 4 to 7.

Figure 4 (a) to c) shows a state in which an elevated water tank with a length of IOm, a depth of 5111, and a height of 2m is installed in a structure with a primary natural period of 10 seconds, and is filled with water to a depth of 1m. This figure illustrates the response when the vibration suppression device is driven by water (weight of 50 tons). Here, it is assumed that the vibration of the structure is a harmonic sine wave (sinωt).

FIG. 4(a) is a diagram showing the vertical movement distance X of an actuator vibrating with a harmonic sine wave (s inωt), where X is expressed by the following equation.

x= 0, 96 sinωt (=sinωt) Same figure (
b) is a diagram showing the horizontal movement distance r of the center of gravity of water caused by the vibration of the actuator, where r is expressed by the following equation.

Figure (c) is a diagram showing the reaction force P exerted on the structure by the elevated water tank due to the horizontal movement of water, and P is expressed by the following formula.

(25-sin"ωt)3 As can be seen from these figures, it can be seen that a large reaction force is generated by attaching a vibration suppression device to a structure.

Figure 5 shows the control force (k
It is a diagram illustrating the relationship between gD and period (seconds). Here, the period is 10 seconds, the first-order damping constant is 2.0%, and the weight is 50
If the control force generated when the top of a 0,000 ton structure vibrates in a sinusoidal manner with 20 gal is determined from the diagram, it will be 0.4 kgf per ton of structure type.

Therefore, in the case of the above-mentioned structure, a control force of 200 tons is sufficient to reduce vibration to a level that does not cause any problem in normal work or daily life. The reaction force exerted by the water tank on the structure is determined from Fig. 4(c).
A reaction force of 4.22 tons can be obtained per water tank (50 tons). Here, the length is 20m, the depth is 20m, and the water depth is 2m.
Assuming that three aquariums are operated in this embodiment, the amount of water will be 2 2 0 3 tons, which is sufficient to cope with the problem.

The above example is an example of consideration for a super high-rise building of about 100 stories, so in a building of about 50 stories, the size of the water tank will be about one-tenth of the above size.

FIG. 6 shows the reaction force P generated when the vibration suppression device of the present invention is driven with an elevated water tank installed in a structure, and
The actuator of the vibration suppression device is attached to the side of the elevated aquarium, and the reaction force P generated when the elevated aquarium is moved horizontally with the same stroke is compared with the reaction force P that occurs when the aquarium has a different shape. be. The ratio between P and P2 is expressed by the following equation.

p + / P 2 − (d”r/ dt2)/ (d”x/ dt') − (
2L/3d) [(2+(1/2)(d/L)')'+
(1/2)(d/L)'+3) Also, the shape of the aquarium is determined by the ratio of the length 2L of the bottom surface to the height d (d
/2L). As can be seen from this figure, the reaction force P generated by installing the vibration suppression device of the present invention is the reaction force P generated by moving the actuator in the horizontal direction.

It turns out that it's much bigger than that. From the figure,
The values of P and /P2 take a minimum value of 6 when the value of d/2L is approximately 0.5. Further, as the value of d/2L becomes smaller than 0.5, that is, as the depth becomes shallower, a very large reaction force is generated. Similarly, the value of d/2L is 0.
It can be seen that the larger the value is than 5, that is, the deeper the depth, the larger the reaction force is generated.

In addition, in the series of studies described in Section 1, it is assumed that water moves quietly, but if the aquarium is shallow or the period is short, the movement of water becomes dynamic and may occur like breaking waves. It shows a nonlinear behavior. The reaction force in this case is even greater than if it were assumed that the water moved quietly. Furthermore, if the tank is further tilted even after the water line reaches the bottom of the tank, the reaction force will be even greater.

Furthermore, in the above study, the movement of the actuator was assumed to be sinusoidal, but this movement is as shown in Figure 7(a).
If the water is moved in a pulse-like manner instantaneously in accordance with the vibration period of the structure, the movement of the water becomes dynamic as shown in FIG. 7(b), and the horizontal movement distance r of the center of gravity of the water increases. Therefore, the acceleration of the center of gravity movement will be much larger,
The reaction force generated will also be quite large. Furthermore, the impact force when the water collides with the side wall of the aquarium is also quite large. In the above case, calculate in advance the time difference between when the water tank is tilted and when the reaction force is generated due to the movement of water, that is, the phase difference of the reaction force, and synchronize it with the phase of the vibration of the structure. It will be even more effective if you do this.

As explained above, the vibrations excited in the high-rise building A can be suppressed by the vibration suppressing device 1 of the present invention.

Here, the vibration suppression device l of this embodiment includes an elevated water tank 3,
Since the main components are a column 2 that supports the central part of the bottom surface 3a of the elevated water tank 3 and two actuators that support both ends of the bottom surface 3a of the elevated water tank 3 so as to be movable in the vertical direction, 5. Compared to the vibration suppressing devices according to the first to third methods, a large vibration suppressing effect can be obtained even with a small device, and there is no need to increase the size of the water tank. therefore,
It becomes possible to significantly simplify the device, downsize it, and save labor.

In addition, since the aquarium is not hung, there is no need to secure a large space, and space can be saved. Furthermore, since there is no need to forcibly apply stress to the water tank to move it in the horizontal direction, the length of the stroke can be shortened, and a long-stroke slide mechanism and large driving force are no longer required. Additionally, unlike the sloshing damper method, there is no need to synchronize the water tank and water volume with the vibration period of the structure, increasing the degree of freedom in design. This makes it fully applicable to general structures such as hotels and residences where people live or live all the time. Furthermore, an effective vibration suppression effect can be obtained even with small vibrations such as those caused by wind.

Note that the details of the structure vibration suppressing device of the present invention are not limited to the above-mentioned embodiments, and various modifications are possible. −
For example, the actuators may be arranged at each of the four corners of the bottom of the water tank 6.

Further, by stacking the water tanks in two layers and arranging them orthogonally to each other and attaching the actuator and control device of the present invention to each tank, expansion in various directions on the horizontal plane becomes possible.

[Effects of the Invention] As described in detail above, according to the present invention, the vibration suppressing device includes a water tank for storing liquid, a column supporting the center portion of the bottom of the water tank, and both ends of the bottom of the water tank. This is a vibration suppression device for a structure equipped with multiple actuators that support the structure so that it can move vertically, so compared to a conventional vibration suppression device using a water tank, even a small device can achieve a large vibration suppression effect. This eliminates the need to increase the size of the aquarium. Therefore, it is possible to significantly simplify the device, reduce its size, and save labor. In addition, since the aquarium is not hung, there is no need to secure a large space, and space can be saved. Also, since there is no need to forcibly apply stress to the aquarium to move it horizontally, the stroke length can be shortened.
A long stroke slide mechanism and large driving force are no longer required. Furthermore, since there is no need to synchronize the water tank and water volume with the period of the structure, the degree of freedom in design increases. This makes it possible to apply the information sufficiently to general structures such as hotels and residences where people live or live all the time.

Furthermore, an effective vibration suppression effect can be obtained even with small vibrations such as those caused by wind.

Therefore, vibrations caused in the structure by external forces such as earthquakes and strong winds can be effectively suppressed, and safety measures at the time of earthquakes and strong winds become more complete.

[Brief explanation of the drawing]

1 to 7 are diagrams showing one embodiment of the present invention, in which FIG. 1 is a schematic front view of a vibration suppressing device, and FIG. 2 (a
) is a schematic diagram showing the elevated water tank in its resting position. Figure (b) is a schematic diagram showing the position when the elevated water tank is tilted by θ-x/L from the resting position. Figure (c) is a schematic diagram showing the elevated water tank in its resting position. A schematic diagram showing the position when tilted by θ-X/shiki in the opposite direction from the position in the same figure (b), Fig. 3 (Explanatory diagram showing the state of control of the vibration suppression device, Fig. 4 (a) is a diagram showing the moving distance of the actuator, (b) is a diagram showing the horizontal movement distance of the center of gravity of water due to the movement of the actuator, and (e) is a diagram showing the reaction force generated by the horizontal movement of the center of gravity of water. 5 is a diagram showing the relationship between the generated control force and the period when the response is reduced to the comfort consideration limit curve, and FIG. 6 is a diagram showing the reaction force P generated by the vibration suppression device of the present invention, and the reaction force P generated when the elevated water tank is moved horizontally (p l/P
2) and the ratio of the length 2L of the bottom of the aquarium to the height d (d/2
FIG. 7(a) is a diagram showing the pulse-like movement of the actuator, and FIG. 7(b) is a schematic diagram showing the movement of the aquarium accompanying the pulse-like movement of the actuator. A...High-rise building, 1...Structure vibration suppression device, 2...Column, 3...
- Elevated water tank, 4... Actuator, 5... Control device, 6... Sensor, 7... Sensor.

Claims (1)

[Claims] A structure vibration suppression device installed at a predetermined position of a structure to suppress vibrations excited in the structure by external forces such as earthquakes and wind, the vibration suppression device comprising a water tank for storing liquid and , a pillar that supports the center of the bottom of the aquarium;
A vibration suppressing device for a structure, comprising: a plurality of actuators that movably support both ends of the bottom surface of the water tank in the vertical direction.