JP2022107290A - Additional mass type vibration control device - Google Patents

Abstract

To provide an additional mass type vibration control device that does not need to adjust its period and is easily maintained without necessary to synchronize its natural period with building's natural period.SOLUTION: An additional mass type vibration control device 10 placed at a top part of a building 11 comprises: an additional mass 12 having 5 to 50% mass of the mass of the building 11; bearing members 13 placed at the top part of the building 11, supporting the additional mass 12 in a vertical direction, and permitting a displacement in a horizontal direction; and attenuation members 14 absorbing seismic energy of the building 11 and restricting the displacement of the additional mass 12. Its natural period is set to be 2.0 to 10.0 times of the natural period of the building 11.SELECTED DRAWING: Figure 2

Description

The present invention relates to an additional mass type vibration damping device, and more particularly to a vibration damping device installed at the top of a building to suppress the shaking of the building in the event of an earthquake or the like.

Along the emergency highway in the city center, there are many buildings with a large aspect ratio that are built on a small site because of the obligation to make a seismic diagnosis. Even if the result of the seismic diagnosis shows that "reinforcement is required", the reinforcement work will be expensive, the burden on the resident will be heavy, and the reinforcement design will be impossible due to structural calculation. There are many buildings left that do not progress to.

Even if vibration damping dampers are arranged in each layer of a building having a large aspect ratio, for example, the energy absorption efficiency is greatly reduced because the dampers are arranged in multiple layers, which makes it difficult to reinforce. In addition, if the dampers are arranged in multiple layers, pile construction is required to bear the force, but many buildings are built on a small site, and the load required for pile construction is large.

As a vibration damping device for measures against shaking of a building during an earthquake, a TMD (Tuned Mass Damper), which is an additional mass type that installs a mass connected to the top of the building via a spring or the like, is known. (See, for example, Patent Document 1). It is conceivable to apply this TMD to a building having a large aspect ratio as described above, but the TMD has the following problems.

-Adjustment is difficult because the natural period of TMD is synchronized (matched) with the natural period (including damage) of the building at the time of an earthquake by adjusting springs and the like.
・ It is an effective method for response control to iso-standing waves (floor vibration, etc.), but it is not effective for non-standing waves such as seismic motion.
-TMD cycle adjustment is required for maintenance against changes in the building's natural cycle due to aging deterioration of the building (cracking of the frame, etc.), changes in the load weight, and changes in the rigidity of the exterior material.

-When a building is deformed to a non-linear region (cracking to member yield) during an earthquake, it is necessary to adjust the TMD cycle for the natural period fluctuation of the building caused by it, but there is no passive adjustment technique.
-Although there is a technology that supports non-standing wave response such as AMD (Active Mass Damper), it is an expensive system.
-It is conceivable to install multiple TMDs on the same layer to cope with the natural period fluctuation of the building to add redundancy to the system, but it not only increases the cost, but also in this case, when installing the TMDs, Period adjustment is required during an earthquake.

Japanese Unexamined Patent Publication No. 2016-223233

The present invention has been made based on the above technical background, and achieves the following object.
An object of the present invention is to provide an additional mass type vibration damping device which does not need to synchronize the natural period of the vibration damping device with the natural period of the building, and therefore does not require cycle adjustment and is easy to maintain.

The inventor of the present invention has obtained the following findings as a result of repeated diligent studies in order to solve the above problems. That is, assuming that a vibration damping device having the same member structure as the TMD (however, the mass of the additional mass is 20% of the building mass) is installed at the top of the building, the natural period of the vibration damping device is set with respect to the natural period of the building. When the shaking of the building during an earthquake was simulated by a computer with various changes, the results shown in FIG. 5 were obtained.

In FIG. 5, the case where the natural period of the vibration damping device is 1.0 times the natural period of the building is the original period setting of TMD (synchronization). If the natural period of the vibration damping device does not match the natural period of the building and is less than 1.0 times smaller than that, or if there is no vibration damping device, the shaking of the building may be larger than that in the case of tuning. I understand.

On the other hand, if the natural period of the vibration damping device does not match the natural period of the building and is set to 2.0 times, 5.0 times, or 10.0 times the natural period of the building, which is larger than that, tuning (1. It was found that the shaking of the building was much smaller than when it was made to (0 times).

Furthermore, the natural period of the vibration damping device is fixed to 2.0 times or 5.0 times the natural period of the building, and the mass of the additional mass of the vibration damping device is variously changed. When the shaking was simulated by a computer, the results shown in FIGS. 6 (period ratio 2.0 times) and FIG. 7 (period ratio 5.0 times) were obtained.

According to the simulation, in both cases of the periodic ratio of 2.0 times and 5.0 times, if the mass of the additional mass is 5% or more of the mass of the building, the building at the time of an earthquake is more than the case where the vibration damping device is not installed. It turned out that the shaking of the was reduced.

The present invention is based on the above findings and employs the following means.
That is, the present invention is an additional mass type vibration damping device installed at the top of a building.
An additional mass having a mass of 5 to 50% of the mass of the building, a support member installed at the top of the building that supports the additional mass in the vertical direction and allows horizontal displacement, and an earthquake in the building. It is equipped with a damping member that absorbs energy and limits the displacement of the added mass.
The additional mass type vibration damping device is characterized in that the natural period is set to 2.0 to 10.0 times the natural period of the building.

Since the vibration damping device according to the present invention sets its natural period to 2.0 to 10.0 times the natural period of the building, it is not necessary to adjust the natural period of the building each time during a large earthquake. That is, there is no need to synchronize.

The mass of a building is, for example, a mass defined by a total weight including a fixed load, a load, a snow load, and the like.

The additional mass can be formed of, for example, concrete, steel, or the like.

The mass of the additional mass is set to 5 to 50% of the mass of the building in order to exert an effective control force against an earthquake. The vibration damping device according to the present invention has its natural period set to be 2.0 to 10.0 times longer than the natural period of the building, and the building and the vibration damping device vibrate independently of each other. Acts as a reaction force to the building.

If the mass of the additional mass is too small, the function as a reaction force cannot be sufficiently obtained. Therefore, in the present invention, the mass of the additional mass is set to 5% or more of the mass of the building. On the other hand, if the mass of the added mass is too large, the balance between the increase in the building weight and the response control at the time of an earthquake becomes unbalanced, and it becomes difficult to install the vibration damping device on the top of the building. Therefore, in the present invention, the mass of the additional mass is set to 50% or less of the mass of the building.

By extending the natural period of the vibration damping device to 2.0 to 10.0 times the natural period of the building, even if the mass of the additional mass is increased to 5 to 50% of the mass of the building, the period is increased. The additional mass is suppressed from acting as the weight during an earthquake.

The natural period of a building can be calculated based on the well-known method of eigenvalue analysis. The calculated natural period can be multiplied by a numerical value of 2.0 to 10.0 to calculate the natural period of the vibration damping device to be set. Then, the mass of the additional mass and the specifications of the bearing member (spring constant, etc.) are determined so as to have the calculated period of the vibration damping device.

As the bearing member, for example, a cylindrical laminated rubber bearing can be used. Laminated rubber bearings are made by laminating a plurality of steel plates and rubber layers, and support a load of additional mass in the vertical direction and allow displacement in the same direction by elastic shear deformation in the horizontal direction. The rigidity (spring constant) at the time of shear deformation in the horizontal direction is one of the parameters that determine the natural period of the added mass.

A plurality of laminated rubber bearings may be arranged in series in the vertical direction. By doing so, it is possible to obtain an advantage that the period of the vibration damping device can be extended without changing the rubber material.

As the bearing member, a spherical bearing may be used in addition to the laminated rubber bearing. The spherical support is formed by sandwiching a sliding material or a sphere between a pair of faces facing each other in the vertical direction, and at least one of the pair of faces is a concave spherical surface. And the additional mass makes a pendulum motion to allow its horizontal displacement. The radius of curvature of the sphere is one of the parameters that determines the natural period of the added mass.

Since the bearing member that performs such a pendulum motion does not include the mass of the additional mass as a parameter that determines the natural period of the vibration damping device, the mass of the additional mass that is actually installed has a slight variation from the design value. Also does not affect the resulting natural period. Further, since the natural period of the vibration damping device is not affected by the mass of the added mass, even if the equipment or the like is unbalancedly loaded on the added mass, a desired natural period to be assumed can be obtained.

As the bearing member, a spherical bearing and a laminated rubber bearing may be arranged in series in the vertical direction. By using such a bearing member, the following advantages can be obtained.

That is, the bearing members that support the additional mass are usually installed at a plurality of places, but when the bearing members are composed of only spherical bearings, each bearing slips due to the difference in frictional properties on the surface of the sliding portion of each spherical bearing. There will be variations in the horizontal force to be exerted. In addition, the horizontal force that slides out also varies due to the bias of the load due to the additional mass applied to the spherical bearings at each location.

For this reason, for example, when the friction coefficient on the surface of the sliding portion is large, it cannot slide in the horizontal direction unless a large horizontal force is applied, and the natural period expected for the vibration damping device cannot be exhibited. Is also possible.

The problem of initial starting when only a spherical bearing is used as such a bearing member can be solved by arranging the spherical bearing and the laminated rubber bearing in series in the vertical direction. FIG. 8 shows a history loop of horizontal displacement when a horizontal load is repeatedly applied to a bearing member in which a spherical bearing and a laminated rubber bearing are arranged in series.

In the figure, the part shown by the broken line shows the displacement at the initial stage of loading in the case of only the spherical bearing, and the horizontal displacement does not occur until the required load (50 kN in the illustrated example) is reached. On the other hand, when the spherical bearing and the laminated rubber bearing are arranged in series, horizontal displacement can be generated from the initial stage of loading as shown by the solid line. As a result, the initial start with respect to the sliding of the horizontal displacement of the bearing member can be improved to prolong the period, and the redundancy can be improved.

When the bearing member has such a configuration, the horizontal displacement acting on the vibration damping device is not concentrated on the laminated rubber, and the spherical surface is formed from the time when a predetermined horizontal force acts on the spherical bearing portion. Since the type bearings will slide out, the laminated rubbers arranged in series do not need to have the deformation ability to follow the deformation (large deformation) acting on the vibration damping device.

In order to obtain the advantage of the serial arrangement of the spherical bearing and the laminated rubber bearing, the horizontal rigidity of the laminated rubber bearing is smaller than the initial rigidity of the spherical bearing (the portion shown by the broken line in FIG. 8). Just set it.

As the damping member, a viscous damper, for example, an oil damper can be used. By providing such a damping member, the energy applied to the additional mass at the time of an earthquake is absorbed, and the response displacement of the additional mass is suppressed.

Since the vibration damping device according to the present invention installs an additional mass having a large mass of 5 to 50% of the mass of the building at the top of the building, it is a medium-low-rise building (S structure, RC structure) with a large aspect ratio built on a narrow site or the like. , SRC structure, wooden structure), but it is also effective not only for reinforcement of existing buildings but also for newly built buildings.

According to the vibration damping device of the present invention, it is not necessary to synchronize the natural period of the added mass with the natural period of the building, and therefore no period adjustment is required and maintenance is facilitated.

It is a front view which shows typically the embodiment of the vibration damping device by this invention. It is a front view which shows the specific structure of the vibration damping device, and shows the Embodiment which made up the support member by the laminated rubber bearing. It is a front view which shows the specific structure of the vibration damping device, and shows the Embodiment which configured the support member by a spherical bearing. It is a front view which shows the specific structure of the vibration damping device, and shows the embodiment which was composed of a spherical bearing and a laminated rubber bearing in which bearing members were arranged in series. It is a graph which shows the maximum response displacement at the time of an earthquake when the mass ratio is 20%, and the natural period ratio of the vibration damping device with respect to the natural period of a building is changed variously. It is a graph which shows the maximum response displacement at the time of an earthquake when the mass ratio of the additional mass to the mass of a building is changed variously with a periodic ratio of 2.0 times. It is a graph which shows the maximum response displacement at the time of an earthquake when the mass ratio of the additional mass to the mass of a building is changed variously with a periodic ratio of 5.0 times. It is a graph which shows the history loop of the horizontal displacement by a repeated horizontal load in the case of having a spherical bearing and a laminated rubber bearing in which bearing members are arranged in series.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view schematically showing an entire embodiment of the present invention. The additional mass type vibration damping device (hereinafter, simply vibration damping device) 10 according to the present invention is installed on the top of the building 11 which is usually called the roof, like the conventional TMD. The building 11 to which the vibration damping device 10 is installed may be an S structure, an RC structure, an SRC structure, a wooden structure, etc., or may be an existing structure or a new structure, but is a medium-low-rise building having a large aspect ratio built on a small site or the like. Suitable for.

The vibration damping device 10 is installed at the top of the building 11 and the additional mass 12, and absorbs the seismic energy of the building and the plurality of support members 13 that support the additional mass 12 in the vertical direction and allow the displacement in the horizontal direction. It also includes a damping member 14 that limits the displacement of the additional mass 12. The conventional TMD also includes these members 12, 13, and 14, and in that respect, the vibration damping device 10 and the TMD of the present invention are similar.

However, in the conventional TMD, the natural period is set so as to match the natural period of the building, whereas in the vibration damping device 10 according to the present invention, it is 2.0 to 10.0 times the natural period of the building 11. The natural period is set so as to be. Further, the mass of the additional mass 12 of the vibration damping device 10 according to the present invention is set to be as large as 5 to 50% of the mass of the building 11 as compared with the additional mass of the conventional TMD.

By setting the natural period of the vibration damping device 10 and the mass of the additional mass 12 in this way, the shaking of the building during an earthquake can be suppressed as compared with the conventional TMD, and the natural period of the vibration damping device 10 can be set to that of the building 11. Maintenance is easy because it is not necessary to synchronize with the natural period.

2 to 4 are front views showing a specific configuration of the vibration damping device 10. FIG. 2 shows an embodiment in which a cylindrical laminated rubber bearing 13a is used as the bearing member 13. The laminated rubber bearing 13a is formed by laminating a plurality of steel plates and rubber layers, and is shear-deformed in the horizontal direction to allow a horizontal displacement of the additional mass 12.

A rectangular frame 15 is installed at the top of the building 11 to install the bearing member 13. Support members 13 are installed at a plurality of locations (four corners) on the frame 15 (the same applies to the embodiments of FIGS. 3 and 4).

In this embodiment, the support members 13 at each location are formed by arranging two laminated rubber support 13a in series in the vertical direction. An intermediate frame 16 is arranged between the frame 15 and the additional mass 12, a lower laminated rubber bearing 13a is arranged between the intermediate frame 16 and the frame 15, and an upper layer is provided between the intermediate frame 16 and the additional mass 12. Laminated rubber bearings 13a are arranged and fixed via upper and lower flanges, respectively.

In the embodiment, the damping member 14 is composed of an oil damper, and is arranged in two upper and lower stages like the laminated rubber bearing 13a. A lower oil damper 14 is attached between the intermediate frame 16 and the frame 15, and an upper oil damper 14 is attached between the intermediate frame 16 and the additional mass 12 via the bracket 17.

At the time of an earthquake, the laminated rubber bearing 13a is sheared and deformed in the horizontal direction, and the additional mass 12 is displaced in the horizontal direction at a natural period set in the vibration damping device 10 to suppress the shaking of the building 11. In addition, the damping member 14 operates to absorb seismic energy.

FIG. 3 shows an embodiment in which spherical bearings 13b are used as the plurality of bearing members 13. The illustrated spherical bearing 13b is a bearing formed by sandwiching a sphere 19 between a pair of upper and lower concave spherical surfaces 18 and 18 facing in the vertical direction. The spherical bearing 13b is arranged between the frame 15 and the additional mass 12, and is fixed via the upper and lower flanges. The spherical support 13b supports the additional mass 12 in the vertical direction, and allows the additional mass 12 to be displaced in the horizontal direction by the upper and lower concave spherical surfaces 18 and 18 being displaced relative to each other in the horizontal direction.

The damping member 14 is made of an oil damper as in the embodiment shown in FIG. 2, and is attached between the additional mass 12 and the frame 15 via a bracket 17.

At the time of an earthquake, a relative displacement in the horizontal direction occurs between the upper and lower concave spherical surfaces 18 and 18 of the spherical support 13b, and the additional mass 12 is displaced in the horizontal direction at a natural period set in the vibration damping device 10 to cause the building 11 to shake. Suppress. In addition, the damping member 14 operates to absorb seismic energy.

FIG. 4 shows an embodiment in which laminated rubber bearings 13a and spherical bearings 13b arranged in series in the vertical direction are used as the plurality of bearing members 13. The laminated rubber bearings 13a and the spherical bearings 13b are the same as those shown in the embodiments of FIGS. 2 and 3, respectively, and these bearings 13a and 13b are fixed to each other via flanges.

The damping member 14 is composed of an oil damper as in the embodiment shown in FIGS. 2 and 3, and is attached between the additional mass 12 and the frame 15 via a bracket 17.

In the case of this embodiment, in the event of an earthquake, the laminated rubber bearing 13a is activated, and then the spherical bearing 13 is activated. That is, the support member 13 composed of the laminated rubber bearing 13a and the spherical bearing 13b operates so as to draw a history loop shown by a solid line in FIG. 8, and the additional mass 12 is set in the vibration damping device 10 for a natural period. Displaces in the horizontal direction with, and suppresses the shaking of the building 11. In addition, the damping member 14 operates to absorb seismic energy.

The spherical bearing 13b is not limited to the examples shown in FIGS. 3 and 4, and a sliding member having a sliding material sandwiched between the concave spherical surfaces 18 and 18 can also be used. It is also possible to use a pair of upper and lower surfaces that sandwich the sphere or the sliding material, and only one of them has a concave spherical surface.

10: Additional mass type vibration damping device 11: Building 12: Additional mass 13: Support member 13a: Laminated rubber bearing 13b: Spherical bearing 14: Damping member 15: Frame 16: Intermediate frame 17: Bracket 18: Concave spherical surface 19: Sphere

Claims (5)

An additional mass type vibration damping device installed at the top of the building.
An additional mass having a mass of 5 to 50% of the mass of the building, a support member installed at the top of the building that supports the additional mass in the vertical direction and allows horizontal displacement, and an earthquake in the building. It is equipped with a damping member that absorbs energy and limits the displacement of the added mass.
An additional mass type vibration damping device characterized in that the natural period is set to 2.0 to 10.0 times the natural period of the building. The additional mass type vibration damping device according to claim 1, wherein the bearing member is made of a laminated rubber bearing. The additional mass type vibration damping device according to claim 2, wherein a plurality of laminated rubber bearings are arranged in series in the vertical direction. The bearing member is formed by sandwiching a sliding material or a sphere between a pair of faces facing each other in the vertical direction, and is characterized by being a spherical bearing in which at least one of the pair of faces is a concave spherical surface. The additional mass type vibration damping device according to claim 1. The bearing member is formed by sandwiching a sliding material or a sphere between a pair of faces facing each other in the vertical direction, and has a spherical bearing in which at least one of the pair of faces is a concave spherical surface, and a laminated rubber bearing. The additional mass type vibration damping device according to claim 1, wherein the and are arranged in series in the vertical direction.

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