JP5164940B2 - Floor excitation force reduction structure - Google Patents

Description

  The present invention relates to a structure for reducing the excitation force of a floor for reducing the excitation force acting due to the movement of a large number of people, etc., acting from the vibration reduction floor supported via an air spring or the like. It is about.

  In the floor of a building where a large number of people operate at a specific frequency at the same time, such as a sports gym studio that performs concert halls or aerobics, the above movement is applied to the foundation from the floor as a vibration force, and this is the same It may be transmitted to another floor on the floor or to the floor on the upper and lower floors to cause vibration disturbance.

Moreover, the vibration resulting from the excitation force may be transmitted from the foundation of the building to the adjacent building via the ground, resulting in the same vibration disturbance.
Therefore, generally for this type of floor, as shown in FIG. 11, a vibration reduction floor 3 is provided on a support structure 1 such as a beam or slab of a building via a spring 2 such as a coil spring or an air spring. The structure to reduce the excitation force to be built is adopted.

  According to such an excitation force reduction structure, the excitation force f acting on the support structure 1 by absorbing the vertical excitation force F by a large number of people operating on the vibration reduction floor 3 by the spring 2. By reducing (F> f), it is possible to suppress the occurrence of vibration disturbances on the adjacent floors and buildings described above. Incidentally, in order to make the excitation force f acting on the support structure 1 smaller than the excitation force F acting on the vibration reduction floor 3, the rigidity of the spring 2 is set to be low and the vibration absorption floor 3 has its own characteristic. It is necessary to make the cycle 1.4 times longer than the excitation cycle.

  By the way, in the above-described excitation force reduction structure, the longer the natural period of the vibration reduction floor 3 is, the higher the effect of reducing the excitation force is, but conversely the response (swing) h of the vibration reduction floor 3 is large. Therefore, it becomes impractical as a floor excitation force reduction structure in which a large number of people operate.

  Therefore, although it is usually dealt with by reducing the response (swing) h of the vibration reduction floor 3 by increasing the mass of the vibration reduction floor 3, in the vibration reduction floor 3 having a large area, Since the total weight increases, there is a problem that the support structure 1 needs to be reinforced separately.

  On the other hand, in the following Patent Document 1, as shown in FIG. 12, the vibration reducing floor 3 is not contacted with the vibration reducing floor 3 in a normal state, and a shocking disturbance is added to the vibration reducing floor 3 in a normal state. A vibration damping device 4 is provided that reduces the response h ′ of the vibration reduction floor 3 by contacting the vibration reduction floor 3 and absorbing a part of the downward momentum when a large response occurs. Shock absorbing structures have been proposed.

  However, since the shock absorbing structure is intended for shocking disturbances and the damping device 4 is also a one-effect damper that absorbs only the downward momentum, it is constantly in the vertical direction. The vibration of the vibration reduction floor 3 is not efficient, and the response of the vibration reduction floor 3 becomes irregular due to repeated operation and release of the vibration control device 4. Therefore, there is a problem that it is not practical as the vibration reduction floor 3 in which a large number of people exercise.

  On the other hand, in Patent Document 2 below, a seismic isolation target structure such as a floor is supported by a support structure below the vertical seismic isolation part, and between the seismic isolation target structure and the support structure. By installing a mass addition mechanism that increases the inertial mass related to vertical vibration by interlocking with the vertical movement of the seismic isolation target structure, Proposed.

  Here, the mass addition mechanism is composed of a disk having a predetermined mass and a ball screw type motion conversion mechanism that rotates the disk in conjunction with the vertical movement of the seismic isolation target structure. By increasing the inertial mass involved in the vertical vibration of the seismic structure, the vertical period of the seismic isolation structure is lengthened.

  However, the above-mentioned vertical seismic isolation device is designed to provide seismic isolation by extending the natural period of the seismic isolation target structure such as the floor against vibrations transmitted from the support structure side during an earthquake. It is not intended to reduce the excitation force acting from the structure side. For this reason, even if it is directly applied to the excitation force reducing structure, the effect of reducing the excitation force acting on the support structure side from the seismic isolation target structure can be enhanced in the same way. It cannot be solved that the response (sway) in the seismic structure is increased.

Japanese Patent No. 4095689 JP 2004-44748 A

  The present invention has been made in view of the above circumstances, can reduce the excitation force acting on the support structure from the vibration reduction floor side, and without increasing the addition to the support structure, It is an object of the present invention to provide a structure for reducing the vibration force of a floor that makes it possible to keep the response of the vibration reduced floor within a practical range.

  In order to solve the above-described problem, the floor excitation force reducing structure according to claim 1 supports the vibration reduction floor on the support structure with the excitation force absorbing member interposed therebetween, and the vibration reduction floor. And a rotary inertia mass damper that provides an additional mass to the vibration reduction floor by rotating due to a vertical displacement of the vibration reduction floor, and the rotation inertia mass damper. ΔM / (M + ΔM) was set in the range of 0.3 to 0.7, where ΔM is the additional mass due to Δ and M is the total mass of the vibration reduction floor supported by the excitation force absorbing member. It is characterized by.

  Here, as the excitation force absorbing member, various springs such as an air spring and a coil spring are suitable.

  According to a second aspect of the present invention, in the first aspect of the present invention, the rotary inertia mass damper is fixed to a ball screw provided rotatably along an axis line along a vertical direction, and fixed to the outer periphery of the ball screw. And a conversion mechanism that converts the vertical movement of the vibration reduction floor into the rotational movement of the ball screw, and the ΔM / (M + ΔM) is in the range of 0.3 to 0.7. The mass of the disk, the radius, and the lead of the ball screw are set.

  According to the first or second aspect of the invention, when an excitation force is applied from the vibration reduction floor, the rotary inertia mass damper is rotated by the vertical displacement to generate an additional mass, and the additional mass reduces the vibration. By increasing the overall inertial mass including the floor, the vibration force acting on the support structure can be reduced more than the vibration force acting on the vibration reduction floor, and at the same time the response of the vibration reduction floor The rotation inertia mass damper can be made smaller than the case where the rotation inertia mass damper is not provided.

At this time, if the proportion of the additional mass is increased with respect to the total mass of the vibration reduced floor plus the additional mass of the rotary inertia mass damper, the mass of the vibration reduced floor can be relatively reduced. However, the effect of reducing the excitation force is reduced.
On the other hand, if the ratio occupied by the additional mass is reduced, the effect of reducing the excitation force can be enhanced, but the effect of reducing the mass of the vibration reduction floor is relatively reduced.

  In this respect, in the present invention, ΔM / (M + ΔM) is set to 0, where ΔM is an added mass by the rotary inertia mass damper, and M is a total mass of the vibration reduction floor supported by the excitation force absorbing member. Since it is set in the range of 3 to 0.7, as will be described later, the excitation force acting on the support structure without excessively increasing the mass of the vibration reduction floor is from the vibration reduction floor. It is possible to reduce the excitation force to 0.7 or less.

  Here, as the rotary inertia mass damper, as in the invention described in claim 2, a ball screw rotatably provided along an axis line along a vertical direction, a disk fixed to the outer periphery of the ball screw, The thing provided with the conversion mechanism which converts the vertical motion of the said vibration reduction floor into the rotational motion of the said ball screw can be used. In this case, ΔM / (M + ΔM) can be easily set in the range of 0.3 to 0.7 by appropriately setting the mass and radius of the disk and the lead of the ball screw.

It is a schematic block diagram which shows one Embodiment of the excitation force reduction structure of the floor concerning this invention. It is a figure which shows the item of the rotary inertia mass damper of FIG. It is a schematic block diagram which shows the item of the excitation force reduction structure used for Example 1 for verifying the effect of this invention. It is a schematic block diagram which shows the specification of the conventional excitation force reduction structure used for the said Example 1. FIG. It is a graph which shows the result of the reduction rate of the exciting force in the said Example 1. FIG. It is a graph which shows the result of the reduction rate of the displacement with respect to an exciting force in the said Example 1. FIG. It is a schematic block diagram which shows the item of the exciting force reduction structure used for Example 2 of this invention. It is a schematic block diagram which shows the specification of the conventional excitation force reduction structure used for the said Example 2. FIG. It is a graph which shows the result of the reduction rate of the exciting force in Example 3 of this invention. It is a graph which shows the result of the reduction rate of the displacement with respect to an exciting force in the said Example 3. It is a schematic block diagram which shows the conventional excitation force reduction structure. It is a schematic block diagram which shows the other conventional excitation force reduction structure.

FIG. 1 and FIG. 2 show one embodiment of a floor vibration force reducing structure according to the present invention, and FIG. 3 to FIG.
As shown in FIGS. 1 and 2, this excitation force reducing structure is applied to the floor of a building such as a concert hall or a sports gym. On the support structure 10 such as a beam or slab of the building, The vibration reduction floor 12 is supported by an excitation force absorbing member 11 made of a spring such as a coil spring or an air spring, and a rotary inertia mass damper 13 is provided between the support structure 10 and the vibration reduction floor 12. is there.

  Here, the vibration period of the vibration generated in the vibration reduction floor 12 when a large number of people operate simultaneously is approximately 0.3 to 0.5 seconds (2 to 3 Hz). The period is set to about 1 second, which is 1.4 times or more of the excitation period.

  The rotary inertia mass damper 13 includes a ball screw 14 having an axis lined along the vertical direction, and a disk 15 fixed to the outer periphery of the ball screw 14, and a lower end portion of the ball screw 14 is supported by A bearing 16 provided on the structure 10 is rotatably supported. Further, the upper end portion of the ball screw 14 is screwed into a nut 17 fixed to the lower surface of the vibration reduction floor 12.

Thereby, the bearing 16 and the nut 17 constitute a conversion mechanism for converting the vertical displacement of the vibration reduction floor 12 into the rotational motion of the ball screw 14.
It is possible to obtain the same effect by fixing the nut 17 on the support structure 10 and providing the bearing 16 on the lower surface of the vibration reduction floor 12.

As shown in FIG. 2, the additional mass ΔM generated by the rotation of the ball screw 14 and the disk 15 of the rotary inertia mass damper 13 is expressed as follows: the mass of the disk 15 is mp; the radius of the disk 15 is R; When L
ΔM = 2 × mp × (π × R / L) ²
Can be calculated.

  As described above, according to the rotary inertia mass damper 13, since the large additional mass ΔM can be obtained by the small mass disk 15, the response (swaying) without increasing the mass of the vibration reduction floor 12. Can be reduced. If the additional mass ΔM is desired to be further increased, the mass mg or radius R of the disk 15 can be increased and the lead L can be reduced.

  In this vibration force reducing structure, the mass mp of the disk 15 in the rotary inertia mass damper 13, the radius R, and the specifications of the lead L of the ball screw 14 indicate that the additional mass by the rotary inertia mass damper 13 is ΔM, and the excitation force When the total mass of the vibration reduction floor 12 supported by the absorbing member 11 is M, the ratio of the additional mass ΔM to the total mass (M + ΔM) of the total mass M of the vibration reduction floor 12 and the additional mass ΔM ( The ratio (ΔM / (M + ΔM)) is set in the range of 0.3 to 0.7.

Next, the grounds for setting ΔM / (M + ΔM) to be in the range of 0.3 to 0.7 will be described based on Examples 1 to 3.
Example 1
First, in order to confirm the effect of the rotary inertia mass damper 13, an excitation force reducing structure provided with the rotary inertia mass damper 13 according to the present embodiment shown in FIGS. 1 and 2 and the rotary inertia shown in FIG. The reduction rate (f / F) of the excitation force and the displacement frequency response in the vibration reduction floors 3 and 12 in the conventional excitation force reduction structure in which the mass damper 13 is not provided were analyzed.

  First, in the structural model, in the present embodiment shown in FIG. 3 and the conventional structure shown in FIG. 4, the mass of the vibration reduction floors 3 and 12 is 3000 kgf, the natural period is 1 second, and the excitation force is 5400 kgf. did. In the present embodiment, the additional mass ΔM of the rotary inertia mass damper 13 is set to 3000 kgf.

  From the comparison of the analysis result of the reduction rate of the excitation force shown in FIG. 5, it can be seen that both can be secured 0.5 times or less at the target frequency of 2 Hz or more. In contrast, as is clear from the analysis result of the displacement frequency response of the vibration reduction floor 12 shown in FIG. 6, according to this embodiment, the response (swing displacement) of the vibration reduction floor 12 is compared with the conventional structure. And it is almost halved.

  From the above, in the excitation force reduction structure of this embodiment provided with the rotary inertia mass damper 13, the vibration reduction floor 12 reduces the vibration of the earthquake without increasing the mass of the vibration reduction floor 12. It was confirmed that it could be

(Example 2)
Therefore, next, when a vertical excitation force (2.0 Hz) of 5400 kgf is applied per 10 m ² of the vibration reduction floor 12, the reduction rate of the excitation force is 0.5 times, the vibration reduction floor 3, An excitation force reducing structure for reducing the sway (displacement) of 12 to 2.3 cm or less was designed for this embodiment and the conventional structure.

FIG. 7 shows a design example in the excitation force reducing structure of the present embodiment, and FIG. 8 shows a design example in the conventional excitation force reducing structure.
From these figures, in the conventional structure, the mass per 10 m ² of the vibration reduction floor 3 needs to be 18000 kgf, whereas in the vibration reduction floor 12 in the present embodiment, 9000 kgf, which is half of the conventional, may be used. In addition, it was confirmed that the load on the support structure 10 can be significantly reduced.

(Example 3)
Next, in the excitation force reduction structure of the present embodiment, the vibration is added under the condition that the natural period of the vibration reduction floor 12 and the sum (M + ΔM) of the total mass M and the additional mass ΔM of the vibration reduction floor 12 are constant. When the ratio ΔM / (M + ΔM) of the mass ΔM was changed from 20% to 80% at intervals of 10%, the change in the vibration force reduction rate and the displacement frequency response of the vibration reduction floor 12 was verified.

9 and 10 show the analysis results.
First, regarding the vibration (displacement) of the vibration reduction floor 12, the total sum (M + ΔM) of the total mass M and the additional mass ΔM of the vibration reduction floor 12 and the natural period (spring constant of the excitation force absorbing member 11) are the same. In addition, all the values are the same regardless of the ratio ΔM / (M + ΔM) of the additional mass ΔM. FIG. 10 shows a case where the ratio of the additional load is 30%.

  On the other hand, as shown in FIG. 8, it can be seen that as the ratio of the additional mass decreases, the reduction rate of the excitation force decreases, that is, the effect of reducing the excitation force increases. And in order to make the said reduction rate into 0.7 or less which is desired, it is necessary to make ratio (DELTA) M / (M + (DELTA) M) of additional mass (DELTA) M with respect to the sum total (M + (DELTA) M) with the vibration reduction floor 12 or less 0.7. is there.

  However, if the ratio of the additional mass ΔM is excessively reduced, the effect of reducing the excitation force can be increased. However, since M + ΔM is constant, it is necessary to relatively increase the mass M of the vibration reduction floor 12. As a result, the mass reduction effect of the vibration reduction floor 12 becomes small.

  For this reason, in order to achieve both the reduction effect of the excitation force and the mass reduction effect of the vibration reduction floor 12, it is necessary to set the ratio of the additional mass ΔM in the range of 0.3 to 0.7. Furthermore, in order to obtain an effective mass reduction effect of the vibration reduction floor 12 while securing about 0.5 as the reduction effect of the excitation force, the ratio of the additional mass ΔM is in the range of 0.4 to 0.6. It is preferable to set to.

  As described above, according to the floor excitation force reducing structure having the above-described configuration, when the excitation force F is applied from the vibration reduction floor 12, the disk 15 of the rotary inertia mass damper 12 is displaced by the vertical displacement. Rotates to generate an additional mass ΔM, and this additional mass ΔM increases the overall inertial mass including the vibration reduction floor 12, thereby applying an excitation force f acting on the support structure 10 to the vibration reduction floor 12. Therefore, the response (swing h) of the vibration reduction floor 12 can be reduced as compared with the case where the rotary inertia mass damper 13 is not provided.

  In addition, the ratio ΔM / (M + ΔM) of the additional mass ΔM to the total mass (M + ΔM) including the total mass M of the vibration reduction floor 12 and the additional mass ΔM is set in a range of 0.3 to 0.7. Therefore, the excitation force f acting on the support structure 10 is reduced to 0.7 or less of the excitation force F from the vibration reduction floor 12 without excessively increasing the mass M of the vibration reduction floor 12. Can be made.

  It can be used as a floor excitation force reduction structure for reducing the excitation force acting due to the movement of a large number of people on the vibration reduction floor supported via an air spring or the like.

DESCRIPTION OF SYMBOLS 10 Support structure 11 Excitation force absorption member 12 Vibration reduction floor 13 Rotation inertia mass damper 14 Ball screw 15 Disk 16 Bearing 17 Nut

Claims (2)

A vibration reduction floor is supported on the support structure via an excitation force absorbing member, and the vibration reduction floor is rotated by a vertical displacement of the vibration reduction floor between the vibration reduction floor and the support structure. By providing a rotary inertia mass damper for adding an additional mass to the vibration reduction floor,
And, when the additional mass by the rotary inertia mass damper is ΔM and the total mass of the vibration reduction floor supported by the excitation force absorbing member is M, ΔM / (M + ΔM) is 0.3-0. A structure for reducing the excitation force of the floor, characterized in that it is set in a range of 7.   The rotary inertia mass damper converts a ball screw rotatably provided with its axis line along the vertical direction, a disk fixed to the outer periphery of the ball screw, and the vertical movement of the vibration reduction floor into a rotary motion of the ball screw. The mass of the disk, the radius, and the lead of the ball screw are set so that the ΔM / (M + ΔM) is in the range of 0.3 to 0.7. The structure for reducing an excitation force of a floor according to 1.

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