JP2004251064A - Vibration-proof construction method for structure floor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration-proof construction method for a structure floor, by which a vibration-proof effect is displayed regardless of the height of the oscillation frequency of exciting force and the difference of the phase of exciting force by supporting only a part of the floor of a structure, to which exciting force works, in a vibration-proof manner. <P>SOLUTION: The floor for the structure is constituted by combining a vibration-proof area supported to exciting force in the vibration-proof manner and a non-vibration-proof area not supported in the vibration-proof manner, the phase of vibrations transmitted from the vibration-proof area to a lower structure is delayed and vibrations are denied and united by utilizing a phase difference with vibrations transmitted from the non-vibration-proof area to the lower structure. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention belongs to the technical field of a vibration damping method for a floor of a structure, and more specifically, a low vibration such as that applied to a floor of an aerobics dance field by a large number of people dancing or jumping to music. The present invention relates to a vibration damping method for a structure floor having a high vibration damping effect even with a number of excitation forces.
[0002]
[Prior art]
Vibration of a structure caused by a large number of humans dancing or jumping to music in response to a jumping motion or the driving force of a press machine, etc., propagates through the frame of the structure and moves up or down the floor, or It is known that horizontal and vertical vibrations (resonances) are induced on floors and beams of nearby structures by propagating along the ground or the ground, causing vibration disturbances such as unpleasant vibrations.
[0003]
This vibration disturbance is mainly caused by a large number of people moving up and down in substantially the same phase in accordance with the rhythm of music. For example, when two exciting forces act in the same phase, the structure generates vibration twice as large as one exciting force. If more exciting forces act in the same phase, the vibration generated in the structure is usually an excessive number of three times, four times,...
[0004]
Conventional anti-vibration technology introduces anti-vibration technology, such as supporting the entire surface of the floor on which the excitation force acts with anti-vibration materials. Vibration transmissibility has been reduced (for example, see Patent Documents 1 to 3).
[0005]
The basic principle of the conventional anti-vibration technique will be described with reference to a single-degree-of-freedom spring-mass model composed of a floor a (mass 2M), a spring k, and a dashpot c shown in FIG. Exciting force Fs0 having the same phase acts on floor a of the structure, and this exciting force is transmitted to lower structure b. Assuming that the transmission force is Fs, the transmission rate Fs / Fs0 is expressed as a general physical phenomenon as shown in FIG. The symbol f shown in FIG. 15 is the frequency of the excitation force Fs0, and fn is the natural frequency of the floor a.
[0006]
As can be seen from FIG. 15, when the natural frequency fn of the floor a is equal to or less than 1 / √2 of the frequency f of the exciting force, that is, when f / fn is larger than √2, the transmissibility Fs / Fs0. Is 1.0 or less, and an anti-vibration effect is observed.
The conventional vibration-proof technology achieves a vibration-proof effect by supporting the floor a so that the transmission rate Fs / Fs0 is 1.0 or less.
[0007]
[Patent Document 1]
Japanese Patent Publication No. 3-3818
[Patent Document 2]
Japanese Patent Publication No. Hei 4-58865
[Patent Document 3]
JP-A-8-53954
[0008]
[Problems to be solved by the present invention]
The above prior art has the following drawbacks when trying to obtain an anti-vibration effect for an in-phase excitation force Fs0 having a low frequency (frequency) f of about 2 to 4 Hz.
[0009]
That is, the excitation force Fs0 when a large number of humans perform a jumping motion of dancing or jumping to the music usually produces a low frequency f of about 2 to 4 Hz. In order to obtain a sufficient vibration damping effect with respect to the excitation force Fs0 having a low frequency f, the floor a must be supported so that the natural frequency fn of the floor a is at least 1 / √2 · f or less. Must.
[0010]
For example, in order to reduce the transmissibility Fs / Fs0 to 0.2 or less with respect to the excitation force f = 2.5 Hz, the transmission rate must be lower than the horizontal dotted line shown in FIG. When the attenuation h = 5%, as shown in FIG. 15, f / fn> 2.5 is lower than the dotted line. That is, in order to set the transmissivity Fs / Fs0 to 0.2 or less, it is necessary to support the floor a in a vibration-isolating manner so that the natural frequency fn of the floor a satisfies fn <1.0 Hz.
[0011]
However, even in the case where an air spring that is effective for a low frequency f is used in the vibration isolating material, the natural frequency fn of the floor a in the vertical direction is set so that fn <1.0 Hz. At present, it is difficult to support vibration-proofing. If the frequency f of the excitation force Fs0 is 2.5 Hz or less, there is a problem that a sufficient vibration-proofing effect cannot be obtained.
[0012]
Further, in the prior art, since the entire surface of the floor a is supported by using the vibration isolating material, a large number of vibration isolating materials and supporting members are required according to the area of the floor a, which leads to an increase in cost. Was.
[0013]
Specifically, the vibration damping technology disclosed in Patent Document 1 sets a phase of reciprocating motion of a plurality of press machines, which is an exciting force Fs0, to be shifted in advance, and sets a vibration wave based on an inertial force of each press machine. The anti-vibration effect is achieved by creating a mode that cancels out. However, according to this anti-vibration technology, it is not possible to apply a structure in which a large number of humans move up and down in substantially the same phase in accordance with the rhythm of music because the phase cannot be set in advance and thus cannot be applied. There is. Further, no solution has been taken for the excitation force Fs0 having a low frequency f of about 2 to 4 Hz.
[0014]
According to the vibration isolation technology disclosed in Patent Document 2, a hollow panel is provided on the entire surface of a floor a on which an exciting force Fs0 acts, and an elastic body having a high-density body is provided inside the hollow panel. Act as a dynamic vibration absorber to effectively absorb the vibration generated in the hollow panel (floor a) to reduce the vibration of the entire panel, thereby achieving a vibration damping effect. However, according to this vibration-proof technology, as described above, since the entire surface of the floor a is supported by vibration-proofing, a large amount of vibration-proof material is required according to the area of the floor a, which is not economical.
[0015]
The vibration damping technology disclosed in Patent Literature 3 is to install an active vibration damping device that generates a damping force in a vertical direction to cancel the vibration in a place where a vibration obstacle of the structure occurs, and to install the vibration in the same place. Drive control of the active vibration suppression device is performed based on vibration information measured by a sensor to achieve a vibration suppression effect. However, according to this anti-vibration technology, the active vibration damping device itself is very expensive, requires a high maintenance cost, and has a problem that the control by the vibration sensor is precise and complicated.
[0016]
An object of the present invention is to provide vibration isolation support for only a part of the floor of a structure on which an excitation force acts, regardless of the magnitude of the frequency of the excitation force and the phase of the excitation force. It is an object of the present invention to provide a vibration damping method for a structural floor that exhibits an effect.
[0017]
SUMMARY OF THE INVENTION An object of the present invention is to provide a vibration damping method for a structural floor having a high vibration damping effect even with an in-phase excitation force having a low frequency of about 2 to 4 Hz, which was difficult to obtain a vibration damping effect at present. Is to provide.
[0018]
An object of the present invention is to provide a vibration-absorbing method for a structural floor with excellent economic efficiency, which exhibits a vibration-proof effect with a simple vibration-proof structure using a general-purpose vibration-proof material such as a vibration-proof rubber, a metal spring, and an air spring. Is to provide.
[0019]
[Means for Solving the Problems]
As means for solving the above-mentioned problems of the prior art, a vibration damping method for a structure floor according to the invention described in claim 1 includes:
The floor of the structure is composed of a combination of an anti-vibration area supported by vibration and a non-vibration area not supported by vibration, and the phase of vibration transmitted from the vibration-isolated area to the lower structure is adjusted. The method is characterized in that the vibration is canceled by using a phase difference between the vibration and the vibration transmitted from the non-vibration-proof area to the lower structure.
[0020]
The invention described in claim 2 is a method for damping a structure floor according to claim 1.
The frequency of the excitation force is f (Hz),
X (0 <X <1.0) is the ratio of the vibration-proof area to the excitation force,
The natural frequency of the vibration isolation area is fn (Hz),
When
When the frequency f of the excitation force and the ratio X of the vibration-proof area are set, the natural frequency fn of the vibration-proof area is
{(1 + 2X) / (1 + X)} ≦ f / fn ≦ {2 / (1-X)}
And tunes the natural frequency of the vibration-proof area so as to fall within the calculated range.
[0021]
According to a third aspect of the present invention, in the vibration damping method for a structural floor according to the first or second aspect, the excitation force acting on the vibration-isolating area and the non-vibration-isolating area is about 2 to 4 Hz having substantially the same phase. Is characterized by a low frequency.
[0022]
According to a fourth aspect of the present invention, in the vibration damping method for a structure floor according to any one of the first to third aspects, the vibration-isolating area and the non-vibration-isolating area are set at substantially the same height. Features.
[0023]
[Embodiments and Examples of the Present Invention]
FIG. 1 shows an embodiment of a method for damping a structure floor according to claim 1.
In this vibration damping method for a structure floor, the floor 1 of the structure 10 is constituted by a combination of a vibration damping area 2 that is supported by vibration and a non-vibration preventing area 3 that is not supported by vibration. The phase of vibration transmitted from the anti-vibration area 2 to the lower structure (foundation, ground, or the floor of a building, etc .; the same applies hereinafter) 4 is delayed, and transmitted from the non-vibration prevention area 3 to the lower structure 4. The present invention is characterized in that the vibrations are canceled out by utilizing the phase difference with the vibrations (claim 1).
[0024]
The non-vibration-proof area 3 in the illustrated example is implemented as the non-vibration-proof area 3 with the lower structure 4 as it is in order to have the simplest structure that does not cause a phase delay. This technical idea is similar to the embodiments described later with reference to FIGS. However, the non-vibration-proof area 3 is not limited to the technical idea of implementing the lower structure 4 as it is, and as shown in FIG. Of course, the non-vibration prevention area 3 can be implemented with the members 8 and 9 interposed.
[0025]
As an example, the present invention provides an area ratio of the vibration-proof supported vibration-proof area 2 and the non-vibration-proof non-vibration-proof area 3 that bears the vibration force (the vibration-proof area 2 and the non-vibration-proof area with respect to the vibration force). (The same applies hereinafter) is set to 1: 1 so that the excitation force acts on each of the areas 2 and 3 by about ず つ each. The area ratio is set to 1: 1 for convenience, but is not limited to this, and can be set to an arbitrary area ratio as described later.
[0026]
The basic principle of the present invention will be described using two spring-mass models of a one-degree-of-freedom system shown in FIG. 2 in comparison with the prior art described with reference to FIGS.
[0027]
In the case of the present invention, the floor 1 of the structure 10 is represented by a combination of a mass model M2 of the vibration-isolated area 2 supported with vibration isolation and a mass model M1 of the non-vibration-isolated area 3 not supported with vibration isolation. , K ′ and dashpots c, c ′.
[0028]
The model shown in FIG. 2 shows that the in-phase excitation force Fs0 acts on the vibration-proof area 2 and the non-vibration-proof area 3 by 1/2 Fs0 at a time.
The transmission force from the non-vibration-proof area 3 not supporting the vibration-proofing to the lower structure 4 is Fs1, the natural frequency of the non-vibration-proofing area 3 is fn1, and the transmission power from the vibration-proofing supporting area 2 to the lower structure 4 is Fs2, the natural frequency of the vibration isolation area 2 is fn2. The transmission force Fs to the lower structure 4 can be represented by the resultant force of Fs1 and Fs2.
[0029]
FIG. 3 shows a phase delay of the vibration transmitted from the vibration isolation area 2 to the lower structure 4. As shown in FIG. 3, there is almost no phase delay in the range where f / fn2 is close to zero, the phase is largely delayed as f / fn2 approaches 1, and the phase delay is increased as f / fn2 becomes sufficiently larger than 1. It turns out that the person becomes stable. Therefore, in the vibration-proof area 2, the transmission rate Fs2 / Fs0 of the excitation force Fs0 and the amount of phase delay change according to the value of f / fn2.
[0030]
On the other hand, in the non-vibration-proof area 3, the natural frequency fn1 becomes very high, so that f / fn1 becomes very small. As a result, the transmissibility Fs1 / Fs0 can be regarded as almost 1/2. In this case, f / fn1 also becomes very small and almost zero for the phase delay. Therefore, since the transmission force from the non-vibration-proof area 3 is almost Fs1 = １ ／ Fs0, it can be considered that the exciting force (１ ／ Fs0) acting on the non-vibration-proof area 3 is transmitted to the lower structure 4 as it is. , It can be considered that there is no phase delay.
[0031]
Here, the transmission force Fs1 in the non-vibration-proof area 3 with the excitation force of 1/2 Fs0 and no phase delay, and the magnitude of the excitation force 1 / 2Fs0 and the amount of phase delay in the vibration-proof area 2 in accordance with the transmission rate. When the transmitting force Fs2 to the lower structure 4 is obtained by adding the changing transmitting force Fs2, the transmitting rate Fs / Fs0 is expressed as a composite as shown in FIG.
[0032]
As can be seen from FIG. 4, when f / fn2 is larger than about √ (4/3), the transmissivity Fs / Fs0 becomes 1.0 or less. Therefore, according to the present invention, the anti-vibration effect can be obtained by supporting the anti-vibration area 2 corresponding to の of the entire floor 1 in a range where the transmission rate Fs / Fs0 is 1.0 or less. I understand.
[0033]
In short, according to the conventional vibration isolation technology, as shown in FIG. 15, a value (f / fn) obtained by dividing the vibration frequency f of the excitation force Fs0 by the natural frequency fn of the floor a must be set to be larger than √2. Since the vibration effect cannot be obtained, when the excitation force Fs0 is a low frequency f of about 2 to 4 Hz, the natural frequency fn cannot be set to be large and the vibration cannot be performed. Although there was a problem that the vibration-proof support structure could not be realized with a general-purpose vibration-proof material, according to the present invention, it is sufficient to set the natural frequency fn2 of the vibration-proof area 2 to be larger than √ (4/3). Even when the vibration force Fs0 is a low frequency f of about 2 to 4 Hz, the vibration-proof support structure can be easily implemented with a general-purpose vibration-proof material such as an air spring (the invention according to claim 3). .
[0034]
In order to explain the effect of the present invention more specifically, an excitation force Fs0 having a frequency f of 2.5 Hz, which is a disadvantage of the related art, will be described as an example. According to the present invention, in order to reduce the transmissibility Fs / Fs0 to 0.2 or less for the vibration frequency f = 2.5 Hz of the excitation force Fs0, it is necessary to lower the horizontal dotted line in FIG. . That is, when the attenuation h = 5%, 1.3 <f / fn2 <1.6, so that the natural frequency fn2 of the vibration isolation area 2 is set to 1.56 Hz <fn2 <1.92 Hz. It is enough to support area 2.
[0035]
On the other hand, in the related art, as described above, in order to reduce the transmissibility Fs / Fs0 to 0.2 or less for the vibration frequency f = 2.5 Hz of the excitation force Fs0, fn <1. It is necessary to support the entire surface of the floor a so as to be 0 Hz, and even when an air spring that works effectively at a low frequency among the vibration isolating materials is used, fn <1.0 Hz in the vertical direction. Thus, it was extremely difficult to support vibration isolation (see also FIG. 5).
[0036]
As described above, according to the present invention, the anti-vibration effect can be obtained by supporting the anti-vibration area 2 occupying half of the entire floor 1 with the relatively high natural frequency fn2, and the air spring can be obtained. It can be easily supported by using a general-purpose anti-vibration material such as, and is very economical.
[0037]
As described above, the area ratio between the vibration-isolated supported vibration-proof area 2 and the non-vibration-proof non-vibration-proof area 3 is set to 1: 1 with respect to the excitation force Fs0. Is implemented in a configuration in which the excitation force Fs0 acts by 1/2 Fs0 at a time, and the vibration isolation area 2 can be vibration-isolated and supported with a higher natural frequency fn2 than in the prior art, so that a vibration isolation effect can be obtained. Not only the excitation force Fs0 of f but also the excitation force Fs0 of the same phase with a low frequency f, which has been difficult in the past, can easily and economically realize an anti-vibration support structure. is there.
[0038]
FIGS. 6A to 6E show vibration transmission rates with respect to f / fn2 when the size of the vibration isolation area 2 is occupied by the ratio (%) to the excitation force Fs0 (the entire floor 1 of the structure 10). FIG. 4 is a graph showing changes individually in comparison with the prior art. FIG. 6F is a graph summarizing them.
[0039]
According to the graphs of FIGS. 6A to 6E and 6F, as the ratio (%) of the vibration-proof area 2 to the excitation force Fs0 gradually decreases, the vibration-proof effect becomes smaller at a smaller value of f / fn2. Is obtained. That is, by supporting the natural frequency fn2 of the vibration-proof area 2 at a larger value, the vibration-proof effect can be obtained, and the vibration-proof material such as an air spring can easily support the vibration-proof. .
[0040]
According to FIGS. 6A to 6E, the vibration isolating method of the present invention sets the ratio (%) of the vibration isolating area 2 to the exciting force Fs 0, thereby reducing the frequency f of the exciting force Fs 0. It is noted that f / fn2 divided by the natural frequency fn2 of the vibration-isolated area 2 supported for vibration isolation can be tuned so that the vibration transmissibility becomes a minimum value in the range of 1 <f / fn2 (particularly, See FIG. 6F).
[0041]
That is, according to the present invention, by setting the ratio (%) of the vibration-proof area 2 to the vibration force Fs0, the specific vibration-proof area 2 can be obtained so that the maximum vibration-proof effect can be obtained. The frequency fn2 can be tuned, and the natural frequency fn of the floor a is set to be as low as possible with respect to the frequency f of the exciting force Fs0. The difference between the effects is remarkable.
[0042]
FIG. 7A shows the value of f / fn2 when the vibration transmission rate reaches 1.0 or less (vibration-proof area) with respect to the ratio X (0 <X <1) of the vibration-proof area 2. This curve can be represented by Y = {(1 + 2X) / (1 + X)}.
[0043]
As shown in FIG. 7A, the smaller the anti-vibration area 2, the smaller the value of f / fn2 at which the vibration transmissibility reaches 1.0 or less, so the natural frequency fn2 of the anti-vibration area 2 increases. It can be seen that the vibration can be supported by setting.
[0044]
FIG. 7B shows a limit value f / fn2 of the ratio X (0 <X <1) of the vibration-proof area 2 where the vibration-proof effect exceeds the conventional vibration-proof effect. This curve can be represented by Y = {(2/1 / X)}.
[0045]
As shown in FIG. 7B, the larger the anti-vibration area 2 is, the larger the limit value that exceeds the anti-vibration effect than the conventional anti-vibration effect can be, and accordingly, the f / fn in the anti-vibration area can be correspondingly increased. It can be seen that the range can be set widely.
[0046]
That is, as shown in FIGS. 7A and 7B, when the ratio X of the vibration proof area 2 is reduced, the natural frequency of the vibration proof area 2 can be set large, but the range of f / fn in the vibration proof area becomes narrow. It can be seen that the frequency f of the force Fs0 can be suitably implemented for operation of a substantially constant press machine. When the ratio X of the vibration-proof area 2 is increased, the natural frequency fn2 of the vibration-proof area 2 must be set relatively small, but the range of f / fn in the vibration-proof area is widened. It can be seen that the frequency f of the force Fs0 can be suitably implemented in an aerobics dance field or the like that fluctuates over time.
[0047]
FIG. 8 shows the value of f / fn2 when the anti-vibration effect is maximized for the ratio X (0 <X <1) of the anti-vibration area 2 when the attenuation constant is 0%. This curve can be represented by Y = {1 / (1-X)}.
[0048]
As shown in FIG. 8, the smaller the anti-vibration area 2, the smaller the value of f / fn2 at which the anti-vibration effect is maximized. Therefore, the natural frequency fn2 of the anti-vibration area 2 is set to be large. It can be seen that vibration proof can be supported.
[0049]
As described above, it is impossible to tune the natural frequency fn2 of the anti-vibration area 2 and actually implement the anti-vibration method with the conventional anti-vibration technology in order to maximize the anti-vibration effect. This is because f / fn must be set to ∞ in order to minimize the vibration transmissibility Fs / Fs0, as shown in the graphs of FIGS.
[0050]
As shown in FIGS. 6 to 8, the anti-vibration area 2 can be implemented at a rate of 50% (X = 0.5), or 25% to 75% (0.25 <X <0). .75), a sufficient anti-vibration effect can be obtained. To put it in extreme terms, the anti-vibration effect can be obtained within the range of 0% <X <100% (0 <X <1) in the ratio of the anti-vibration area 2. Therefore, the ratio of the vibration-proof area 2 to the excitation force Fs0 is not limited, and the vibration-proof effect can be obtained even if the vibration-proof area 2 is arbitrarily set and implemented. Can be realized.
[0051]
In summary, the frequency of the excitation force is f (Hz), the ratio of the vibration isolation area to the excitation force is X (0 <X <1.0), and the natural frequency of the vibration isolation area is fn (Hz). When the vibration frequency f of the excitation force and the ratio X of the vibration-proof area are set, the natural frequency fn of the vibration-proof area is calculated as √ ｛(1 + 2X) / (1 + X) based on FIGS. 7A and 7B. By calculating from the formula {≦ f / fn ≦ {2 / (1-X)} and tuning the natural frequency of the vibration-proof area so as to fall within the calculated range, the vibration-proof area with respect to the excitation force Fs0 is obtained. Regardless of the size of the second embodiment, it is possible to realize a vibration-proofing method that exerts a vibration-proofing effect that is superior to the conventional technology (the invention according to claim 2).
[0052]
By the way, as shown in FIG. 2, the basic principle of the present invention is based on the premise that the excitation force Fs0 generated on the floor 1 (the vibration-proof area 2 and the non-vibration-proof area 3) has the same phase. It is not necessarily limited to perfect in-phase.
[0053]
When the phases are different, for example, when the one whose phase is delayed with respect to two exciting forces Fs0 having a phase difference of 30 degrees is supported for vibration isolation, the graph shown in FIG. 9A (or FIG. 3) is the graph shown in FIG. 9B. , The value approaches the value at which the anti-vibration effect is maximized (the amount of phase delay = 180 deg), and a more efficient anti-vibration effect can be obtained.
[0054]
In this case, as shown in FIG. 9C, the vibration transmissibility (Fs / Fs0) changes, so that the damping effect is larger at 10% attenuation than at 0% attenuation, and amplification at the resonance frequency is performed. And a design that can effectively exhibit the vibration isolation effect becomes possible.
[0055]
As described above, according to the vibration isolating method for the floor 1 of the structure 10 described in claim 1, the ratio of the vibration isolating area 2 to the vibration force Fs0 (the entire floor 1) and the vibration Regardless of the level of the frequency f of the force Fs0 and the phase of the excitation force Fs0, the floor 1 of the structure 10 to which the vibration is transmitted by the excitation force Fs0 is divided into the vibration-isolated area 2 and the non-vibration-isolated area. 3, the phase of the vibration transmitted from the anti-vibration area 2 to the lower structure 4 is delayed, and the vibration is transmitted using the phase difference from the vibration transmitted from the non-vibration prevention area 3 to the lower structure 4. By canceling each other, the vibration damping effect can be exhibited reasonably and efficiently, and more economically.
[0056]
Incidentally, when the structure 10 shown in FIG. 1 is used as a live house such as a rock band that mobilizes hundreds to thousands of spectators, a large number of people dance or jump to music. The structure 10 is implemented assuming that the exciting force Fs0 having a low frequency of about 2 to 4 Hz and substantially the same phase is generated with the movement.
[0057]
Further, when the structure (live house) 10 according to the present embodiment is implemented by raising the floor 1 of the rear audience seat one step higher so that the stage can be easily seen from the audience seat, a part of the floor 1 is subjected to vibration isolation. The material 5 is used for the vibration isolating area 2 with the material interposed therebetween, thereby achieving the vibration isolating effect for the entire transmission force to the lower structure 4.
[0058]
Specifically, the anti-vibration area 2 according to the present embodiment protects a part of the floor 1 of the structure on the upper surface of a part (about 50% area) of the lower structure 4 constituting the non-vibration prevention area 3. The vibration member 5 is installed in a well-balanced manner and is implemented with a double floor structure supported by vibration isolation. Although the vibration isolator 5 in the illustrated example is made of a vibration isolating rubber, it can be implemented in a similar manner by using an air spring or a metal spring.
[0059]
The double-floor structure is not limited to this configuration, and it is needless to say that the floor 1 can be implemented by supporting the floor 1 in a variety of ways according to the purpose of a concert or a sporting event. For example, as shown in FIG. 10, if necessary, the anti-vibration area 2 may be provided in a grid pattern, and the lattice-shaped gap may be used for the passage 14. The anti-vibration method according to the present invention can exhibit an anti-vibration effect without being restricted at all by the ratio of the anti-vibration area 2 to the excitation force (the entire floor 1), so this type of design is very easy. It is.
[0060]
The non-vibration-proof area 3 according to the present embodiment is implemented by a concrete lower structure (foundation floor) 4 itself. Note that the configuration of the non-vibration-proof area 3 is not limited to this. For example, as shown in FIGS. 11 and 12, on the condition that a phase delay of vibration due to the excitation force Fs0 is not caused in the lower structure 4. The concrete 7 is integrally cast on the lower structure 4 (FIG. 11), the concrete pillar 8 is cast, and the concrete floor 9 is constructed thereon (FIG. 12). It can also be implemented at a height.
[0061]
In the embodiment shown in FIGS. 11 and 12, the non-vibration-proof area 3 is configured by casting concrete 7 or the like so that a step is not provided between the vibration-proof area 2 and the non-vibration-proof area 3. An embodiment suitable for use in an aerobics studio or the like is provided by matching the height of the anti-vibration area 2 to the implementation (the invention according to claim 4).
[0062]
Also in these embodiments, the phase of the vibration transmitted from the vibration-proof area 2 to the lower structure 4 is delayed, and the phase difference between the vibration transmitted from the non-vibration-proof area 3 and the lower structure 4 is used. Irrespective of the ratio of the vibration isolation area 2, the frequency f of the excitation force Fs0, and the difference in the phase of the excitation force Fs0. Can economically obtain the anti-vibration effect.
[0063]
Although the embodiment has been described above with reference to the drawings, the present invention is not limited to the embodiment of the illustrated example, but may be applied to design changes and application variations normally performed by those skilled in the art without departing from the technical idea thereof. Mention is made to include ranges.
[0064]
For example, the structure 10 shown in FIGS. 13A and 13B shows an embodiment of the present invention relating to a multipurpose structure (multipurpose dome) capable of accommodating a large number of people for the purpose of a concert, a sporting event, or the like.
[0065]
In this vibration-proofing method for the floor 1 of the multipurpose structure 10, the multipurpose structure 10 uses a field (non-vibration-proof area) 3 as a so-called arena seat, and its peripheral portion (vibration-proof area) 2 serves as a general audience seat. When used as a concert venue for a rock band or the like accommodating about 30,000 to 50,000 people in total, the audience performs about 2 to 4 Hz by performing a jumping motion to dance or jump to music. This is performed under the assumption that the exciting force Fs0 having substantially the same phase as the low frequency f is generated.
[0066]
The anti-vibration area 2 is formed on the upper floor of the lower structure 4 constituting the non-vibration-proof area 3, and on the upper surface of the column 11, which is a rigidly constructed base frame composed of columns 11 and beams 12. (Anti-vibration rubber) 5 is installed, and a part of the floor 1 is supported in an anti-vibration manner in a stepwise manner at a required step corresponding to the height of the column material 11. The anti-vibration area 2 can be embodied as a movable seat that can be slid by providing casters 13 on the legs of the pillar 11 as necessary. Incidentally, reference numeral 15 in FIG. 13B indicates a foundation pile, and reference numeral 16 indicates a foundation beam.
[0067]
Also in the case of this embodiment, the phase of the vibration transmitted from the anti-vibration area 2 to the lower structure (ground) 4 is delayed based on the basic principle described above, and the lower structure (ground) is transmitted from the non-vibration prevention area 3. The vibration can be canceled out by utilizing the phase difference with the vibration transmitted to the vibration force 4, the ratio of the vibration-proof area 2, the frequency f of the vibration force Fs0, and the phase of the vibration force Fs0. Regardless of the difference, the vibration damping effect can be exhibited reasonably and efficiently, and more economically.
[0068]
[Effects of the present invention]
According to the vibration damping method for a structure floor described in claims 1 to 4, the following effects can be obtained.
(1) Only a part of the floor of the structure on which the excitation force acts can be vibration-isolated and supported, and can be implemented with a simple structure, which is economical.
(2) Regardless of the ratio of the vibration isolation area to the structure floor on which the excitation force acts, the magnitude of the excitation frequency of the excitation force, and the difference in the phase of the excitation force, the vibration isolation effect is obtained. Because it can be achieved, it is excellent in flexibility.
(3) The vibration-proof effect is high even for the same-phase excitation force of a low frequency of about 2 to 4 Hz, which was difficult to obtain the vibration-proof effect at present, and furthermore, a vibration-proof rubber, a metal spring, and air The vibration damping effect can be achieved by using a general-purpose vibration damping material such as a spring, which is excellent in economic efficiency.
(4) The floor area on which the excitation force acts is extremely wide ranging from a relatively small structure such as an aerobics dance field to a large-scale structure such as a multipurpose structure capable of accommodating tens of thousands of people. In contrast, the vibration damping effect can be rationally and efficiently, and more economically.
(5) It can be applied not only to new structures but also to existing structures.
[Brief description of the drawings]
FIG. 1 is a perspective view schematically showing a vibration damping method for a structural floor according to the first aspect of the present invention.
FIG. 2 is a spring-mass model showing a basic principle of a vibration damping method for a structure floor according to the present invention.
FIG. 3 is a graph showing a phase lag of a transmission force (Fs2) from an anti-vibration area supported by anti-vibration to a lower structure.
FIG. 4 is a graph showing a vibration transmissibility according to the present invention.
FIG. 5 is a graph showing the vibration transmissibility according to the related art and the present invention in comparison.
FIG. 6A is a graph showing a vibration transmissibility when the vibration isolation area is 25%,
B is a graph showing the vibration transmissibility when the vibration-proof area is 33%,
C is a graph showing the vibration transmissibility when the vibration-proof area is 50%,
D is a graph showing the vibration transmissibility when the vibration isolation area is 66%,
E is a graph showing the vibration transmissibility when the vibration isolation area is 75%,
F is a graph collectively showing the above AE.
FIGS. 7A and 7B are graphs showing the basis for determining the range of f / fn in the structural floor vibration isolating method according to the second aspect of the present invention. A graph of the value of f / fn2 when the vibration transmissibility reaches 1.0 or less (vibration-proof area) with respect to the ratio of the vibration-proof area is shown. The graph of the value of f / fn2 of the limit value which a vibration-proof effect exceeds the conventional vibration-proof effect is shown.
FIG. 8 is a graph showing the value of f / fn at which the anti-vibration effect can be maximized with respect to the ratio of the anti-vibration area.
FIGS. 9A and 9B are graphs comparing effects when a phase delay occurs, and FIG. 9C is a graph illustrating the vibration transmissibility of B;
FIG. 10 is a perspective view showing a different embodiment of a vibration damping method for a structure floor according to the first aspect of the present invention.
FIG. 11 is a perspective view showing an embodiment of a vibration damping method for a structure floor according to the invention described in claim 4;
FIG. 12 is a perspective view showing an embodiment of a vibration damping method for a structure floor according to the invention described in claim 4;
FIG. 13A is a bird's-eye view showing a different embodiment of a structure floor vibration damping method according to the first aspect of the present invention, and B is a partial cross-sectional view thereof.
FIG. 14 is a spring-mass model showing the basic principle of the prior art.
FIG. 15 is a graph showing a general physical phenomenon.
[Explanation of symbols]
1 floor
2 Anti-vibration area
3 Non-vibration-proof area
4 Substructure (foundation, ground, floor of building)
5 anti-vibration materials
7 concrete
8 concrete columns
9 concrete floor
10 Structure

Claims (4)

The floor of the structure is composed of a combination of a vibration-isolated area that is supported by vibration isolation and a non-vibration-proof area that is not supported by vibration, and the phase of vibration transmitted from the vibration-isolated area to the lower structure is adjusted. A vibration damping method for a structural floor, wherein the vibration is canceled by utilizing a phase difference between the vibration and the vibration transmitted from the non-vibration-proof area to the lower structure. The frequency of the excitation force is f (Hz),
X (0 <X <1.0) is the ratio of the vibration-proof area to the excitation force,
The natural frequency of the vibration isolation area is fn (Hz),
When
When the frequency f of the excitation force and the ratio X of the vibration-proof area are set, the natural frequency fn of the vibration-proof area is set to {(1 + 2X) / (1 + X)} ≦ f / fn ≦ {2 / (1) −X)｝
The vibration damping method for a structural floor according to claim 1, wherein the natural frequency of the vibration damping area is tuned so as to fall within the calculated range. The vibration force applied to the vibration-isolated area and the non-vibration-isolated area is a low frequency of about 2 to 4 Hz having substantially the same phase, wherein the vibration is applied to the structure floor according to claim 1 or 2. Construction method. The vibration-proofing method for a structural floor according to any one of claims 1 to 3, wherein the vibration-proof area and the non-vibration-proof area are set at substantially the same height.

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