JP7088664B2 - Vibration prevention frame for structural floors - Google Patents

Description

The present invention relates to a vibration-preventing frame for a structural floor that can effectively prevent low-frequency vertical vibrations that occur in large-scale facilities such as concert halls and live houses.

In large-scale facilities such as concert halls and live houses, a large number of viewers dance and jump to the music played by musicians, causing low-frequency vertical vibration (longitudinal vibration) on the floor of the structure. ) Occurs.
In recent years, when large-scale facilities such as concert halls and live houses have become even larger and accommodate an extremely large number of viewers, low-frequency vertical vibrations caused by viewers dancing and jumping occur. The power is also extremely large.

Here, as shown in FIG. 1, the high-power vertical vibration is transmitted to the pillar 102, the foundation 103, etc. via the structural floor 101 of the large-scale facility 100, and the ground 104 directly under the large-scale facility 100 is also transmitted. It will vibrate in the vertical direction.
Further, this vertical vibration is transmitted to the ground 105 around the large-scale facility 100, but as it is transmitted to the surrounding ground 105, the vertical vibration is attenuated and the ratio of the horizontal vibration is higher. Will increase.
Then, when a building 106 having the same natural frequency as the propagating ground vibration exists in the vicinity, a phenomenon that the building 106 vibrates violently (resonance) occurs with the ground vibration.

Therefore, by isolating the structural floor of a large-scale facility where vertical vibration occurs and reducing the vibration transmission rate, the vibration propagation to the surrounding ground is reduced, and the surrounding buildings resonate. A construction method has been proposed to prevent this from occurring (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2006-057260

The anti-vibration method disclosed in Patent Document 1 is composed of an anti-vibration area 2 in which the structure floor 1 is anti-vibration supported and a non-vibration anti-vibration area 3 in which the structure floor 1 is not anti-vibration supported, and the vibration transmitted to the underfloor structure 4 is generated. The phases are different, and the vertical vibration is canceled by this phase difference.

However, the vibration-proofing method disclosed in Patent Document 1 has almost no effect of canceling vertical vibration unless there is a great difference in the phase difference between the vibration-proofing area 2 and the non-vibration-proofing area 3.
On the other hand, since the anti-vibration area 2 is too flexible, it is easy for the viewer or the like to swing even when walking normally, and it cannot be said that the anti-vibration performance is high.
Further, since it is necessary to separate the vibration-proof area 2 and the non-vibration-proof area 3, a gap is formed between the vibration-proof area 2 and the non-vibration-proof area 3, and a step is likely to occur between the floor surfaces of both. ..
Further, since it is necessary to separate the vibration-proof area 2 and the non-vibration-proof area 3, the structure of the structure floor 1 becomes complicated, and there is a problem that a large amount of time and cost are required for construction.

The present invention has been made in view of such conventional problems, has a large effect of attenuating vertical vibration generated by longitudinal vibration, and does not cause inconvenient gaps or steps on the floor surface. It is an object of the present invention to provide an anti-vibration frame for a structural floor, which does not complicate the structure of the structural floor and does not require a large amount of time and cost for construction.

In order to achieve the above object, the anti-vibration frame of the structural floor of the present invention is an anti-vibration frame of the structural floor in a large-scale facility in which low-frequency vertical vibration is generated by the behavior of a large number of viewers. There,
From ultra-high-strength steel of at least 80 kg steel or more, which supports the upper floor surface on which a large number of viewers are placed, has a long span of 20 to 60 m, and has a small beam length of 500 to 2,000 mm. Beam material and
Supporting materials installed at both ends of the beam material so as to simply support the beam material, and
A damping damper disposed between the beam material and the floor surface of the lower floor at the central portion in the length direction of the beam material,
A weight body exhibiting a massive body that can be suspended and arranged in an appropriate number at an appropriate position of the beam material by a suspension material that can be freely locked to the beam material.
It is characterized by being composed of.

Here, it is preferable to use full-web H-shaped steel as the beam material.
Further, the support material is composed of a bottom plate portion fixed to the pillar material and a support portion having an insertion hole, and the support shaft is inserted through the insertion hole, and one end of the beam material is inserted into the support shaft. The beam member may be pin-supported by pivotally supporting the portion.

According to the vibration prevention frame of the structural floor of the present invention, the effect of dampening the vertical vibration generated by the longitudinal vibration is large, no inconvenient gaps and steps are generated on the floor surface, and the structure of the structural floor is complicated. It does not require a lot of time and money for construction.

It is explanatory drawing which shows the transmission process to the surrounding ground of a longitudinal vibration. It is sectional drawing of the vibration prevention frame of the structure floor of this invention. It is sectional drawing of the beam material shown in FIG. FIG. 2 is an enlarged cross-sectional view of a main part of an embodiment of one end portion (simple support end portion) of the beam material shown in FIG. FIG. 2 is an enlarged cross-sectional view of a main part of another embodiment of the beam material shown in FIG. 2 at one end (simple support end). FIG. 2 is an enlarged cross-sectional view of a main part of another embodiment of the beam material shown in FIG. 2 at one end (simple support end). It is a schematic diagram of the vibration system by the vibration prevention frame shown in FIG. It is a graph which shows the response magnification when a harmonic external force acts on the vibration system of a natural frequency 1Hz. It is a graph which shows the relationship between the reduction rate and the damping ratio when the external force of 2Hz which simulated the longitudinal vibration is applied to the model of 1 mass system. It is a plan view of a concert hall. FIG. 10 is a cross-sectional view taken along the line AA of FIG. FIG. 10 is a cross-sectional view taken along the line BB of FIG.

A preferred embodiment of the vibration-preventing frame of the structural floor of the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 2, the structure floor vibration prevention frame 1 of the present invention includes a long-span beam material 3 having a small beam structure that supports the upper floor surface 2 and a support material that simply supports the beam material 3. 4. It is composed of a damping damper 6 arranged between the beam member 3 and the lower floor surface 5, and a weight body 7 suspended below the beam member 3.

The beam material 3 is an ultra-high-strength steel such as 80 kg steel or 100 kg steel, and as shown in FIG. 3, the beam width B is 400 to 1,200 mm and the beam formation (height) H is 500 to 2, It is preferable to use H-shaped steel having a length (span) of 20 to 60 m and a length of 000 mm.
Further, as long as it has the same performance as the above, I-shaped steel, box-shaped steel, steel having a rectangular cross section, etc. may be adopted, and in the case of a beam end portion used for a portion having a small stress. There is no problem even if 50 kg steel or the like is used.

Here, the length (span) L of the beam material 3 is set to a long span of 20 to 60 m, and the beam formation H is made significantly smaller than the length (span) L of the beam material 3, for example, H / By setting L to 1/30 to 1/50, a floor having a small natural frequency is realized.

In addition, the beam response may be large when the high-order mode matches the vibration frequency of 2 to 3 Hz or its harmonic frequency of 4 to 6 Hz. Therefore, the beam is a full-web simple beam in the primary mode. Is predominant, and a vibration system is configured so that the secondary mode does not become 2 to 3 Hz.

Since the support member 4 simply supports the beam member 3, for example, as shown in FIG. 4, the support member 4A is composed of a non-shrink mortar 44, a bottom plate portion 41, and a support portion 42, and the bottom plate portion 41 is bolted. , The support shaft 43 is inserted into the insertion hole 42a formed in the support portion 42 by fixing it to the upper surface portion of the pillar member 8 with a nut or the like, and one end of the beam members 3 and 3 is pivotally supported by the support shaft 43. Thereby, the beam members 3 and 3 may be pin-supported.

Further, as shown in FIG. 5, the support material 4B is composed of a non-shrink mortar 44, a bottom plate portion 41, a seat portion 45, and a round steel rod 46, and the upper end surface of the seat portion 45 is curved. The bottom plate portion 41 and the seat portion 45 may be fixed to the upper surface portion of the column member 8 with bolts, nuts, or the like while being brought into contact with the lower end surface of the round steel rod 46.
Here, the round steel rod 46 is coated with a fluororesin such as polytetrafluoroethylene at least in the vicinity of the lower end surface so as not to cause scratches on the lower end surface and prevent rolling, and is under the beam material 3. It is fixed to the end face by welding or the like.
In addition, in order to secure the strength in the support portion, the rib plate 31 is fixed to the beam material 3 by welding or the like.

Further, as shown in FIG. 6, the support member 4C is composed of a non-shrink mortar 44, a bottom plate portion 41, and a seat portion 47, and the upper end surface of the seat portion 47 is curved and under the beam material 3. The bottom plate portion 41 and the seat portion 47 may be fixed to the upper surface portion of the pillar material 8 with bolts, nuts, or the like while being brought into contact with the end surface.
Here, the seat portion 47 is coated with a fluororesin such as polytetrafluoroethylene at least in the vicinity of the upper end surface so as not to cause scratches on the upper end surface and prevent rolling.
In addition, in order to secure the strength in the support portion, the rib plate 31 is fixed to the beam material 3 by welding or the like.

The damping damper 6 is arranged at the central portion of the beam member 3 in the length direction in order to retain a drag force against the downward bending of the central portion of the beam member 3 in the length direction and to absorb the vibration.
As the damping damper 6, a damper such as an oil damper or a viscous wall that does not affect the natural frequency can be adopted.

The weight body 7 is provided in order to adjust the natural frequency of the beam material 3 to the target value and to reduce the response acceleration of the floor surface, and as shown in FIG. 2, it is freely locked to the beam material 3. The hanging material 71 suspends and arranges the beam material 3 at an appropriate position by an appropriate number.

The weight body 7 does not contribute to the bending rigidity of the beam material 3 at all, and efficiently utilizes the space between the upper floor surface 2 and the lower floor surface 5 and is economical. In consideration, iron is molded into a rectangular shape.

By making it possible to add or decrease the number of weights 7, it is possible to cope with an increase or decrease in the response acceleration of the upper floor surface 2.

Further, the suspending material 71 does not contribute to the bending rigidity of the beam material 3 at all, and a round steel rod, a molded steel material, or the like can be adopted.

According to the vibration prevention frame 1 of the structural floor of the present invention, a vibration system as shown in FIG. 7 is configured, and the equation of motion when an external force f (t) is applied to this vibration system is

my "+ cy'+ ky = f (t)

It can be expressed as.
Here, m is a mass, c is a viscosity coefficient, k is an elastic modulus, and y is a displacement.

Further, the force F (t) transmitted to the ground and the reduction rate R are respectively.

F (t) = cy'+ ky
R = F (t) / f (t)

It can be expressed as.

In the vibration system as shown in FIG. 7, the response magnification when a harmonized external force acts on the vibration system having a natural frequency of 1 Hz is shown in FIG.
In FIG. 8, the range of 2.0 to 3.0 Hz is defined as the natural frequency region of the longitudinal vibration.

Further, in a vibration system as shown in FIG. 7, the relationship between the reduction rate R and the damping ratio h when an external force of 2 Hz simulating longitudinal shear vibration is applied is shown in FIG.

According to the graph shown in FIG. 9, it can be seen that when the damping ratio h is 0.2 and the natural frequency f is 0.6, the reduction rate R is about 0.3.
This indicates that, for example, when 10,000 people are vertically glued, the force transmitted to the ground can be reduced to the same level as when 3,000 people are vertically glued.

Next, the entire structure and element design of the vibration prevention frame 1 of the structural floor of the present invention will be described step by step.

First, the plane dimension of the floor surface 2 on the upper floor, the number of viewers assumed to exist on the floor surface 2, that is, the number of vibrations is set.

Next, the target response acceleration is set when the viewer jumps and vertical vibration occurs, or when walking and vertical vibration occurs.

Next, assuming a desired damping amount, the weight of the vibration prevention frame 1 required to achieve the target response acceleration is calculated.
As a result, the weight and the number of the weights 7 are determined.

Next, the target reduction rate Ro when longitudinal vibration occurs is set, and the target natural frequency of the vibration prevention frame 1 that achieves this target reduction rate Ro is calculated.
Here, it is desirable that the target natural frequency of the vibration prevention frame 1 is 1 Hz or less, particularly 0.5 to 1 Hz, as it is possible to reduce the external force of 2 to 3 Hz simulating the longitudinal vibration.
Thereby, the rigidity of the beam member 3 is determined.

Next, it is confirmed whether the vertical response displacement is within the permissible value when the target natural frequency calculated above is used.
If it exceeds the permissible value, review the rigidity or damping amount of the beam material 3.

The strength design of the beam material 3 satisfying the rigidity and the weight determined by following the above procedure is executed, and the whole and element design of the vibration prevention frame 1 of the structural floor of the present invention is completed.

As described above, the vibration prevention frame 1 of the structural floor of the present invention is difficult to control after the floor surface is made to respond to an external force, so it is made based on the technical idea of eliminating the factor from the beginning. It is a thing.
That is, in the sense that the infrasound spring is realized by the vibration prevention frame 1, it is different from the one to which the finishing material and the vibration-proof rubber are attached.

If the vibration prevention frame 1 of the structural floor of the present invention designed and configured as described above is applied, vertical glue generated in a large-scale facility such as a concert hall 200 or a live house as shown in FIGS. 10 to 12 Vibration can be effectively prevented.

Here, since the weight body 7 can be suspended and arranged in an appropriate number at an appropriate position of the beam member 3, the target of the vibration prevention frame 1 can be unique to the vibration prevention frame 1 by changing the number of vibrations, the installation equipment, and the like. Even if the frequency changes, it can be dealt with flexibly.

Further, the vibration prevention frame 1 of the structural floor of the present invention can also be applied to a mechanical parking lot, a research facility, an experimental facility, a mechanical facility, etc. where vertical vibration is likely to occur.

In the concert hall 200, as shown in FIGS. 11 and 12, the parking lot 202 is often installed on the lower floor of the hall 201, but the beam material 3 supporting the floor surface 2 of the hall 201 is arranged in a long span. For example, the number of pillars to be installed on the lower floors is reduced, the degree of freedom in design is increased, and a space for accommodating a larger number of vehicles can be constructed.

In the vibration prevention frame 1 of the structural floor, the beam material 3 bends downward by about several tens of centimeters due to its own weight. Therefore, the beam material 3 is deformed in advance so that it becomes horizontal at the time of installation. You may.
Alternatively, after the bending due to its own weight is completed, a horizontal floor surface may be formed by a finishing material that does not change the rigidity or the weight.

Further, if the damping damper 6 is provided with a locking mechanism, the damping performance can be varied, and a damping mechanism corresponding to the facility to be applied can be realized.

As described above, according to the vibration prevention frame of the structural floor of the present invention, the effect of dampening the vertical vibration generated by the longitudinal vibration is large, and the structure of the structural floor is not complicated. It is extremely useful because it does not require a lot of time and money for construction.

1 Anti-vibration frame 2 Upper floor surface 3 Beam material 4 Support material 5 Lower floor floor surface 6 Damping damper 7 Weight body 8 Pillar material

Claims (3)

It is a vibration prevention frame for the floor of a structure in a large-scale facility where low-frequency vertical vibration is generated by the behavior of a large number of viewers.
From ultra-high-strength steel of at least 80 kg steel or more, which supports the upper floor surface on which a large number of viewers are placed, has a long span of 20 to 60 m, and has a small beam length of 500 to 2,000 mm. Beam material and
Supporting materials installed at both ends of the beam material so as to simply support the beam material, and
A damping damper disposed between the beam material and the floor surface of the lower floor at the central portion in the length direction of the beam material,
A weight body exhibiting a massive body that can be suspended and arranged in an appropriate number at an appropriate position of the beam material by a suspension material that can be freely locked to the beam material.
A vibration-preventing frame for the floor of a structure characterized by being composed of. The vibration-preventing frame for a structural floor according to claim 1 , wherein the beam material is a full-web H-shaped steel . The support material is composed of a bottom plate portion fixed to the pillar material and a support portion having an insertion hole, and a support shaft is inserted through the insertion hole, and one end of the beam material is inserted into the support shaft. The vibration-preventing frame for a structural floor according to claim 1 or 2 , wherein the beam member is supported by a pin by pivotally supporting the beam .

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