JP2009007916A - Vibration damping structure and its specification setting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration damping structure which can obtain a satisfactory response reduction effect without the need for an excessive added mass such as a conventionally standard TMD (Tuned Mass Damper) while theoretically functioning like the TMD, and to provide its specification setting method. <P>SOLUTION: An intermediate story 5 to be used as an intermediate floor (for example, a mezzanine second floor) is installed between arbitrary inter-stories (for example, between the first and the second floors) in a building, a building frame of the intermediate story is supported in horizontally displaceable manner to the building frames of the upper story and the lower story via their respective upper and lower support members (suspension members 6 and intermediate pillars 7), an additional spring 10 is interposed between the intermediate story and the upper story or the lower story, and an additional vibration system constituted of the intermediate story, the upper and lower support members and the additional spring is provided in the building. The natural vibration frequency of the additional vibration system to be determined by the mass m<SB>0</SB>in the intermediate story, the story rigidity k<SB>01</SB>between the intermediate story and the upper story, the story rigidity k<SB>02</SB>between the intermediate story the lower story and the spring constant k<SB>0</SB>of the additional spring, is synchronized with the natural vibration frequency of the building. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vibration damping structure for reducing vibration of a building and a specification setting method thereof.

  As a mechanism for reducing the vibration of a building, for example, a so-called Tuned Mass Damper (TMD) as shown in Patent Document 1 is known. This is because an additional mass is installed on the building via an additional spring and additional damping, and the natural frequency of the additional vibration system determined by the additional mass and the additional spring is tuned to the natural frequency of the building as the main vibration system. By doing so, the response near the resonance point is reduced.

Further, Patent Document 2 discloses that a horizontal lower floor of a building is separated by separating the outer frame from the lower floor of the building and the internal frame, separating the internal frame and the foundation, and installing a damping device therebetween. There is a disclosure about a vibration damping method and a vibration damping structure in which the rigidity is lowered to increase the period and the horizontal deformation concentrated on the lower floor is effectively attenuated by the damping device.
JP-A 63-156171 JP 2000-345732 A

In the conventional general TMD as shown in Patent Document 1, it is necessary to increase the added mass sufficiently in order to obtain a sufficient vibration reduction effect, but it is not realistic to add too much mass to the building. Usually, the limit is about 1 to 2% of the building's own weight, and therefore the vibration control effect is naturally limited.
Moreover, although the vibration suppression method and the vibration suppression structure shown in Patent Document 2 can achieve both vibration suppression and seismic isolation effects, they do not intend the vibration suppression effect by frequency tuning like TMD. Therefore, the response near the resonance point cannot be sufficiently reduced.

  In view of the above circumstances, the present invention functions in principle similar to TMD, but the vibration damping structure and its various features that can provide a sufficient response reduction effect without requiring a special additional mass like conventional TMD. The purpose is to provide an original setting method.

In the vibration damping structure and its specification setting method of the present invention, an intermediate layer to be used as an intermediate stage is installed between arbitrary layers in a building, and the intermediate layer frame is supported above and below the upper and lower frame respectively. Additional vibrations are supported by the intermediate layer, upper and lower support members, and additional springs by interposing an additional spring between the intermediate layer and the upper layer or lower layer while supporting the member so that it can be displaced horizontally. A system is provided in the building, and the mass m ₀ of the intermediate layer, the layer rigidity k ₀₁ between the intermediate layer and the upper layer, the layer rigidity k ₀₂ between the intermediate layer and the lower layer, and the additional spring The natural frequency (or natural angular frequency) of the additional vibration system determined by the spring constant k ₀ is synchronized with the natural frequency (or natural angular frequency) of the building.

  According to the present invention, an intermediate layer used as an intermediate stage such as a mezzanine floor is provided between the original layers constituting the main structure of the building, and the mass of the intermediate layer is used as a weight in the TMD mechanism. Thus, unlike the conventional TMD mechanism, a weight or a spring that is a heavy load on the building is unnecessary, and the mass can be sufficiently increased to, for example, 10% or more of the total mass of the building, Therefore, an excellent vibration damping effect can be obtained, and it is effective not only for small amplitudes such as wind loads and traffic vibrations but also for reducing the response during a large earthquake, and an extremely rational and effective vibration damping mechanism can be realized.

  One embodiment of the present invention is shown in FIGS. The embodiment of the illustrated example is an application example to a three-story building. FIG. 1 shows a frame of the entire building as a frame model, and FIG. 2 shows a vibration model. 1st layer, 1st floor, 2nd floor, 2nd floor, 3rd floor, 3rd floor, 3rd floor, 3rd floor The main structure is a four-layered frame, but a large aerial space is secured between the first layer (first floor) 1 and the second layer (second floor) 2 inside such a main structure. Then, there is provided an intermediate layer 5 that constitutes a floor beam in the middle stage (in this case, the middle second floor), and the mass of the frame of the intermediate layer 5 is used as an additional mass to function as a TMD mechanism. The main focus.

That is, in this embodiment, an intermediate layer 5 used as a mezzanine floor is provided between the first layer 1 and the second layer 2, and the intermediate layer 5 serves as an upper support member from the second layer 2 that is the upper layer. The suspension material 6 is suspended and supported by the intermediate pillar 7 as a lower support member from the first layer 1 which is the lower layer.
In this embodiment, the column base of the inter-column 7 is pin-bonded to the first layer 1, so that the intermediate layer 5 can be relatively vibrated in the horizontal direction between the first layer 1 and the second layer 2. The relative vibration of the intermediate layer 5 is controlled by the vibration damping device 8.
The damping device 8 in the illustrated example is installed in the form of a stud between the intermediate layer 5 and the second layer 2, which is a damper for attenuating horizontal vibration of the intermediate layer 5 as shown in FIG. 9 and an additional spring 10 installed in parallel thereto. The vibration damping device 8 may be installed either above or below the intermediate layer 5, instead of being installed between the intermediate layer 5 and the second layer 2 as shown in the illustrated example. You may install between the 1st layer.

The vibration damping structure of the present embodiment having the above structure is a vibration model in which the intermediate layer 5, the upper and lower supporting members 6, the intermediate pillars 7, and the vibration damping are compared with the main vibration system of the main structure of the entire building. The additional vibration system constituted by the apparatus 8 is incorporated, and the natural frequency of the additional vibration system is as shown in FIG. 2, that is, the mass m ₀ of the intermediate layer 5, the intermediate layer 5 and its The layer stiffness k ₀₁ between the second layer 2 that is the upper layer, the layer stiffness k ₀₂ between the intermediate layer 5 and the first layer 1 that is the lower layer, and the above-mentioned vibration damping device 8 It is determined by the spring constant k ₀ of the additional spring 10.
Specifically, when the natural frequency of the additional vibration system is expressed as a natural angular frequency, the natural angular frequency ω _d is determined by the relationship of the following equation from the above specifications.

In this embodiment, the natural vibration frequency ω _d of the additional vibration system determined by the above equation is tuned to the natural angular frequency of the building, particularly the primary natural angular frequency ω ₁ , so that the additional vibration system by the intermediate layer 5 is used. In other words, the mass m ₀ of the intermediate layer 5 is used as an additional mass in the TMD mechanism, which requires a special additional mass as in a normal TMD mechanism. In addition, a sufficient additional mass necessary for obtaining a desired vibration damping effect can be secured without any trouble, thereby effectively attenuating vibration in the vicinity of the resonance point of the primary mode of the entire building. is there.

The intermediate layer 5 is not necessarily provided between the first floor and the second floor as an intermediate second floor, and may be provided between arbitrary layers, but is preferably installed at a position where the interlayer displacement increases particularly during an earthquake. .
The setting of the resonance point is not limited to the primary natural (angular) frequency of the building, but if it is tuned to a specific natural (angular) frequency to be controlled, the response near the resonance point is reduced. Can do.
Further, the area of the intermediate layer 5 may be smaller than the areas of the other layers that originally constitute each floor, and the center of gravity of the plane of the intermediate layer 5 is preferably the center of the building, but is eccentric. It does not matter. This is because the response reduction effect due to the mid-layer vibration control is generally greater than the influence of the torsional response due to the eccentricity (a premium effect).
Further, as described above, since the intermediate layer 5 is supported from above and below by the suspension members 6 and the pillars 7 as the upper and lower support members, even when the natural frequency of the intermediate layer 5 is small (becomes a long cycle). It can be stably supported and does not easily generate an excessive displacement amplitude. Note that supporting the intermediate layer 5 from above and below means that the springs are attached to the upper and lower sides of the intermediate layer 5 respectively, and in that respect, the vibration characteristics are different from those of the conventional general TMD mechanism in which the springs are attached to only one of the upper and lower sides. It will be a little different, but it will remain the same.

Hereinafter, a specific example of the vibration damping structure of the present embodiment will be further described.
In the vibration model shown in FIG. 2, when the vibration direction displacement of the mass point j (j = 1 to 3) is x _j and the balance equation of the stationary coordinate system (absolute displacement) of the mass point j is displayed, the following equation is obtained.

As shown in FIG. 2, it is assumed that the masses m ₁ , m ₂ , m ₃ , rigidity k ₁ , k ₂ , k ₃ , damping c ₁ , c ₂ , c ₃ of each layer of the main structure are equal, and m ₁ = M ₂ = m ₃ , k ₁ = k ₂ = k ₃ , and c ₁ = c ₂ = c ₃ .
Assuming that the displacement x is a sinusoidal vibration x _j = x _j e ^iωt with an angular frequency ω, ω ₀ ² = k ₁ / m ₁ ,
It is assumed that h ₁ = c ₁ / (2m ₁ ω ₀ ) and ξ = ω / ω ₀ .
The structural attenuation of the intermediate layer is ignored and c ₀₁ = c ₀₂ = 0.
For the mass, (￣m ₀ ) = m ₀ / m ₁ and for the spring, (￣k ₀₁ ) = k ₀₁ / k ₁ , (￣k ₀₂ ) = k ₀₂ / k ₁ . For the additional spring, (￣k ₀ ) = k ₀ / k ₁ , and the additional damping h ₀ is h ₀ = c ₀ / (2m ₁ ω ₀ ).
Note that (￣m ₀ ) represents that a ￣ (bar) is added to the top of m ₀ (the same applies to other symbols).

  Using these values, the vibration equation is summarized in matrix form as follows:

X _j / x _g (absolute value of complex number, j = 1 to 3) obtained from this equation indicates the displacement response magnification of each mass point with respect to the excitation input. Note that the response magnification for the vibration input is the same for the displacement, velocity, and acceleration.

The analysis results when each specification is specifically set as follows are shown below.
The mass of the intermediate layer 5 is 0.2 times the masses m _{1 to} m ₃ of the other layers. That _is, the _{m 0 = 0.2m 1 (m 1} = m 2 = m 3).
The layer stiffness k ₀₁ between the intermediate layer 5 and the second layer 2 is 0.015 times the other layer stiffnesses k _{1 to} k ₃ , and the layer stiffness k ₀₂ between the intermediate layer 5 and the first layer 1 is. Is 0.0075 times the other layer rigidity k _{1 to} k ₃ . _{That, k 01 = 0.015k 1, k} 02 = 0.0075k 1 to _{(k 1 = k 2 = k} 3).
The additional attenuation due to the damping coefficient c ₀ of the damper 9 is h ₀ = c ₀ / (2m ₁ ω ₀ ) = 0.1
And The structural attenuation of the main structure is assumed to be h ₁ = 0.02.
The additional spring 10 in parallel with the damper 9 is set to k ₀ = 0.001k ₁ , so that the natural angular frequency ω _d of the additional vibration system is changed to the primary natural angular frequency ω ₁ (≈0.35ω ₀ ) of the entire building. Tune in.

The response reduction effect when each item is set as described above is shown by a transfer function, and the result is shown in FIG.
From the results shown in FIG. 3, it can be seen that the response reduction mechanism (TMD mechanism) using the mass effect of the intermediate layer (second mezzanine) is also effective against earthquakes.
In other words, by using only about 20% (0.2 times) the mass of the general floor, the maximum value is 1/4 or less (the maximum response is reduced by 78%), and a large response reduction effect can be obtained. Therefore, for example, the present invention is sufficiently applicable to an architectural plan in which a part of the atrium is used as a mezzanine floor. In addition, the floor of the middle second floor does not have an excessive amplitude, and falls within the same or lower level as the second floor when vibration is not suppressed.
In addition, since the above is an example of analysis when synchronized with the primary natural frequency of the building, naturally the vibration of the primary mode is greatly reduced. That is, in the figure, ξ = ω / ω ₀ = 0.35 is the resonance point of the primary mode of the building, and the response is reduced only in the vicinity thereof. Moreover, it can be seen that the vibration of the entire building can be effectively suppressed not only in the vicinity of the second floor but also to the top by damping the vibration on the second floor.

According to the vibration damping structure of the present invention, the effects listed below can be obtained.
(1) Since the mass of the intermediate layer used as an intermediate stage such as the mezzanine floor is used as a weight, weights and springs (laminated rubber, coil springs, etc.) that are loads on the building are not required unlike conventional TMD mechanisms. Become. Since the mass of the intermediate layer necessary for the architectural plan is used as a weight, it can be realized at a much lower cost than a conventional TMD mechanism that requires a special weight as a TMD mechanism.
(2) Although the conventional TMD mechanism could practically give only about 1 to 2% of the weight of the building, according to the present invention, a part of the building is used as a weight. It can be realized relatively easily. Therefore, it is effective not only for small amplitudes such as wind loads and traffic vibrations but also for reducing response during a large earthquake. In addition, it is a response reduction mechanism that is effective not only for earthquakes that are accelerated from the fixed end (the ground surface), but also for wind loads that act on the building as an excitation force. In addition, since the mass of the weight is larger than that of the conventional TMD, the frequency range in which the response can be reduced is wide, and even if the weight of the intermediate layer fluctuates by about 10% or the loaded load fluctuates by about 50%, it functions without problems. And can exhibit a stable response reduction effect.

(3) Since the mass of the intermediate layer is used as a weight, a larger mass can be given compared to the conventional TMD mechanism, so when the intermediate layer is integrated with the main structure (that is, the intermediate layer is not used for damping) Compared with the case), both the main structure and the intermediate layer can reduce the response. This is the same effect as vibration control between two buildings that can reduce both responses by connecting the two buildings via a damper. Therefore, by adopting this vibration damping mechanism, the habitability of the middle class is not reduced (having the same or better habitability as when no vibration is suppressed).
(4) The middle layer is generally provided at a position where the floor height of the main structure is large, such as the middle two floors. However, a floor with a large floor height naturally reduces layer rigidity and increases interlayer displacement. Naturally, it is easy to demonstrate the damping effect and it is reasonable.
(5) Even if an intermediate layer is installed only in a specific part of a building, a large response reduction effect can be obtained against a wide range of disturbances from minute amplitude to large amplitude, so interlayer dampers (brace dampers, damping walls, etc.) on each floor It is easier to incorporate in the building plan than in the case of a normal vibration control structure. The specific location is not necessarily limited to the middle second floor (between the first floor and the second floor), but a location where the interlayer deformation is large is more effective. Moreover, if it installs in two or more places in a height direction, a response can be reduced more.

(6) The intermediate layer may be installed only at a specific location, and the vibration control device may be installed either above or below the intermediate layer, so that the installation cost can be sufficiently low.
(7) Since the response reducing mechanism uses the inertial mass effect as in the conventional TMD mechanism, the effect can be exerted from a minute amplitude, and a normal damping structure using a damping damper such as a general steel damper It is different from the one that exhibits the effect only after the steel material yields.
(8) The present invention is a mechanism for preventing an increase in response due to the resonance of the building, and can greatly reduce the response displacement and reaction force in the vicinity of the resonance point, and is also effective in reducing the burden on the underground foundation and preventing lifting. Is. In addition, the habitability is improved by reducing the response displacement of the general part.
(9) The frequency tuning operation after installing the TMD mechanism of the present invention can be easily handled by adjusting the value of the additional spring as in the case of the conventional TMD mechanism.

(10) The vibration damping structure of the present invention can be used in combination with a normal viscous damping system or a hysteretic damping damper, thereby further enhancing the response reduction effect.
(11) The present invention can be said to be a vibration control frame closely related to the construction plan. It is a mass-effect type vibration control mechanism that uses a part of the building casually as a weight, does not have a movable mechanism using laminated rubber or sliding obstacles, and is not different from a normal earthquake-resistant frame in terms of appearance and frame . Further, in the conventional TMD mechanism, it is generally arranged at the top of the building. However, in the present invention, it is effective to arrange it at the lower part such as the mezzanine floor. Further, in the conventional TMD mechanism, the amplitude of the weight portion is very large and is not suitable for living. However, in the present invention, the amplitude of the intermediate layer can be suppressed to the same level or lower than that in the case where the vibration is not suppressed. By making an architectural plan that makes use of these characteristics, it is possible to design an attractive building that is low-cost and excellent in earthquake resistance.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and of course, the scale and form of the building, the structure, the application, the position of the intermediate layer, and the intermediate layer with respect to the upper and lower layers. The structure of the support member for supporting relative vibrations, the form of support by them, the structure and installation form of the damping device for controlling the vibration of the intermediate layer, and other specific details of the details It goes without saying that arbitrary design changes can be made without departing from the scope of the invention.

FIG. 2 is a diagram illustrating a vibration damping structure according to an embodiment of the present invention, in which a frame of the entire building is illustrated as a frame model. It is the figure shown as a vibration model. It is a figure which shows the analysis result for demonstrating an effect similarly.

Explanation of symbols

1 First layer (1st floor)
2 Second layer (2nd floor)
5 Middle layer (middle stage)
6 Suspension material (support member)
7 studs (support members)
8 Damping device 9 Damper 10 Additional spring

Claims (2)

An intermediate layer to be used as a middle stage is installed between arbitrary layers in the building, and the intermediate layer housing is supported from the upper layer and lower layer housings through a support member so as to be horizontally displaceable, and the intermediate layer and the upper layer or By providing an additional spring between the lower layer, an additional vibration system constituted by the intermediate layer, upper and lower support members and an additional spring is provided in the building,
It is determined by the mass m ₀ of the intermediate layer, the layer rigidity k ₀₁ between the intermediate layer and the upper layer, the layer rigidity k ₀₂ between the intermediate layer and the lower layer, and the spring constant k _{0 of the} additional spring. A damping structure characterized in that the natural frequency of the additional vibration system is synchronized with the natural frequency of the building. An intermediate layer used as an intermediate floor is installed between arbitrary layers in the building, and supports the intermediate layer frame so that it can be horizontally displaced through the upper and lower support members with respect to the upper layer and the lower layer frame, respectively. In the vibration control structure in which an additional vibration system including the intermediate layer, the upper and lower support members, and the additional spring is provided in the building by interposing an additional spring between the intermediate layer and the upper layer or the lower layer. A specification setting method,
It is determined by the mass m ₀ of the intermediate layer, the layer rigidity k ₀₁ between the intermediate layer and the upper layer, the layer rigidity k ₀₂ between the intermediate layer and the lower layer, and the spring constant k _{0 of the} additional spring. A specification setting method for a damping structure, wherein the natural frequency of an additional vibration system is synchronized with the natural frequency of a building.

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