JP6895274B2 - Floor structure - Google Patents

Description

The present invention relates to a floor structure that reduces floor vibration.

There is a floor vibration damping method that reduces floor vibration by using a vibration damping damper such as a viscous damper or a viscoelastic damper. For example, Patent Document 1 discloses a viscoelastic damper that reduces floor vibration by pin-connecting both ends to the upper and lower floors constituting the structure.

In the floor damping method that reduces floor vibration using a damping damper, in order to efficiently exert a high damping effect, support the vicinity of the center of the floor where the amplitude of the floor vibration is the largest and the periphery of the floor. It is effective to provide a damping damper so as to connect to a support structure (beam or column) that does not vibrate very much.

However, in this case, the damper length of the damping damper (horizontal distance between the installations of the damping dampers) becomes long, and the damping damper must be placed in the underfloor space (attic space) that is narrow in the height direction. Must be.

Therefore, the damping damper is arranged at an angle with a small inclination, and therefore the displacement amount of the damping damper does not increase, so that the damping force of the damping damper is effective against the vertical vibration generated on the floor. It will not be possible to demonstrate it.

Japanese Unexamined Patent Publication No. 6-49923

In consideration of such facts, it is an object of the present invention to effectively exert the damping force of the vibration damping damper against floor vibration.

In the invention of the first aspect, a floor portion having a rectangular plane shape whose peripheral edge is supported by a support structure and a free end provided on the peripheral edge of the floor portion by cutting the edge between the floor portion and the support structure. It is a floor structure having a portion, a vibration damping damper connecting the free end portion and the support structure.

In the invention of the first aspect, by providing the free end portion on the peripheral edge of the floor portion, a position where the floor portion vibrates significantly in the vibration mode of the floor portion is created on the free end portion side of the floor portion, and the free end portion and the support structure are formed. By connecting the above with a vibration damping damper, the floor vibration can be efficiently reduced by the vibration damping damper.

In addition, compared to installing a damping damper so as to connect the vicinity of the center of the floor with the support structure, the horizontal distance between the installations of the damping damper is shorter, so that the vertical vibration generated on the floor is not affected. The damping damper can be arranged so that the damping force can be effectively exerted. That is, the damping force of the vibration damping damper can be effectively exerted against the floor vibration.

In the invention of the second aspect, in the floor structure of the first aspect, two free ends are provided so as to face each other.

In the invention of the second aspect, by providing two free ends on the floor, it is possible to disperse the positions of large vibrations in the vibration mode of the floor toward the two free ends. This makes it possible to use a vibration damping damper with a small damping force.

The invention of the third aspect has a beam provided along the free end and supporting the free end in the floor structure of the first or second aspect.

In the invention of the third aspect, the bending of the free end portion under a static load can be reduced by the beam provided along the free end portion and supporting the free end portion.

Since the present invention has the above configuration, the damping force of the vibration damping damper can be effectively exerted against the floor vibration.

It is a top view which shows the floor structure which concerns on embodiment of this invention. FIG. 1 is a cross-sectional view taken along the line AA of FIG. It is a side view which shows the mounting state of the vibration damping damper which concerns on embodiment of this invention. It is a top view which shows the conventional floor structure. It is a side sectional view which shows the conventional floor structure. It is a top view which shows the conventional floor structure. FIG. 6 is a cross-sectional view taken along the line BB of FIG. It is a perspective view which shows the model of the conventional floor slab. It is a perspective view which shows the primary vibration mode type obtained by the numerical simulation with respect to the model of the conventional floor slab. It is a perspective view which shows the model of the floor slab provided with a free end part. It is a perspective view which shows the primary vibration mode type obtained by the numerical simulation with respect to the model of the floor slab provided with a free end part. It is a perspective view which shows the model of the floor slab based on the floor structure which concerns on embodiment of this invention. It is a diagram which shows the value of the gain of the transfer function with respect to the frequency obtained by the numerical simulation with respect to the model of the floor slab based on the floor structure which concerns on embodiment of this invention, and the model of the conventional floor slab. It is a side sectional view which shows the variation of the vibration damping damper which concerns on embodiment of this invention. It is a side sectional view which shows the variation of the vibration damping damper which concerns on embodiment of this invention. It is a top view which shows the variation of the floor structure which concerns on embodiment of this invention. It is a top view which shows the variation of the floor structure which concerns on embodiment of this invention.

An embodiment of the present invention will be described with reference to the drawings. First, the floor structure according to the embodiment of the present invention will be described.

As shown in the plan view of FIG. 1 and FIG. 2 which is a cross-sectional view taken along the line AA of FIG. 1, the floor structure 10 of the present embodiment has a floor slab 12 (enclosed by a chain line) having a rectangular planar shape as a floor portion. It is configured to have a free end portion 14 provided on the peripheral edge of the floor slab 12 and a viscous damper 16 as a vibration damping damper.

The peripheral edge of the floor slab 12 is supported by columns 18 as support structures forming columns to be the skeleton and girders 20 as support structures to form peripheral beams to be the skeleton. The floor slab 12 and the column 18 are made of reinforced concrete, and the girder 20 is made of H-shaped steel.

In the present embodiment, of the entire peripheral edges of the floor slab 12 having a rectangular planar shape, the peripheral edges 22 and 24 forming two opposite sides in a plan view and the end portions of the peripheral edges 22 and 24 in a plan view are connected to each other. The peripheral edge portion 26, which constitutes one side connecting the two, is supported by the pillar 18 and the girder 20. As described above, the floor slab 12 as the floor portion may support a part of the entire peripheral edge of the floor slab 12 so that the entire floor slab 12 is supported.

The floor slab 12 constitutes a large-span floor having a large span between supports by columns 18 and girders 20. Further, the floor slab 12 is supported by a beam 28 having both ends supported by the pillar 18 and a beam 30 having one end supported by the pillar 18. The beams 28 and 30 are formed of H-shaped steel and are arranged in a grid pattern.

A slit 32 is formed in the peripheral edge portion 34 of the floor slab 12 facing the peripheral edge portion 26 in a plan view, whereby the peripheral edge portion 34 becomes a free end portion 14. That is, the free end portion 14 is provided on the peripheral edge of the floor slab 12 by cutting the edge between the support structure (column 18 and the girder 20) and the floor slab 12. Further, the free end portion 14 of the floor slab 12 is supported by a small beam 36 as a beam provided along the free end portion 14. The beam 36 is made of H-section steel.

As shown in FIG. 3, the viscous damper 16 supports the girder 20 as a support structure and the free end portion 14 of the floor slab 12 (the free end portion 14 of the floor slab 12 is fixed to the upper end portion). One is arranged so as to connect the beam 36. That is, the free end portion 14 of the floor slab 12 and the girder 20 are connected by a viscous damper 16.

The lower end 38 of the viscous damper 16 is pin-connected to the gusset plate 40 provided at the lower end of the girder 20, and the upper end 42 of the viscous damper 16 is the gusset plate 44 provided at the upper end of the beam 36. It is pin-connected to. As a result, the viscous damper 16 is arranged so that the orientation 46 of the viscous damper 16 (the operating direction of the viscous damper 16) has a large inclination.

Next, the action and effect of the floor structure according to the embodiment of the present invention will be described.

In the floor structure 10 of the present embodiment, as shown in FIGS. 1 and 2, by providing the free end portion 14 in the floor slab 12, the position where the floor slab 12 vibrates significantly in the vibration mode is set to the free end of the floor slab 12. By connecting the free end portion 14 and the girder 20 that hardly generates vibration in the vibration mode of the floor slab 12 with the viscous damper 16, the floor vibration of the floor slab 12 is generated by the viscous damper 16. It can be reduced efficiently.

In the plan view of FIG. 4 and the side sectional view of FIG. 5, a conventional floor structure that reduces the floor vibration of the floor slab 50 (the portion surrounded by the alternate long and short dash line) by using a vibration damping damper 48 such as a viscous damper. 52 examples are shown.

In order to efficiently obtain a high vibration damping effect on the floor slab 50 by using the vibration damping damper 48 as in the floor structure 52, the floor vibration amplitude of the floor slab 50 is the largest in the vibration mode of the floor slab 50. The vibration damping damper 48 connects the vicinity of the floor central portion 54, which becomes large, with the girder 20 and the pillar 18 as the support structure supporting the peripheral edge of the floor slab 50, which causes almost no vibration in the vibration mode of the floor slab 12. It is effective to provide. FIG. 4 shows an example in which a vibration damping damper 48 is provided so as to connect the vicinity of the floor central portion 54 and the pillars 18 arranged at the four corners of the floor slab 50.

However, in this floor structure 52, the damper length of the vibration damping damper 48 (horizontal distance d between the installations of the vibration damping damper 48) is long, and the space under the floor 56 (the space behind the ceiling) is narrow in the height direction. The damping damper 48 must be placed.

Therefore, the vibration damping damper 48 is arranged at an angle with a small inclination, and therefore the displacement amount of the vibration damping damper 48 does not increase. Therefore, the vibration damping damper 48 is arranged against the vertical vibration generated in the floor slab 50. It becomes impossible to effectively exert the damping force.

On the other hand, in the floor structure of the present embodiment, as shown in FIG. 3, the floor structure 52 (FIG. 3) in which the vibration damping damper 48 is installed so as to connect the vicinity of the floor central portion 54 and the support structure (pillar 18). Compared with 4 and FIG. 5), the horizontal distance between the installations of the viscous damper 16 is shorter, so that the damping force can be effectively exerted against the vertical vibration generated in the floor slab 12. The viscous damper 16 can be arranged (in the example of FIG. 3, the orientation 46 of the viscous damper 16 (the operating direction of the viscous damper 16) can be made close to the vertical direction). That is, the damping force of the viscous damper 16 can be effectively exerted against the floor vibration of the floor slab 12.

Further, in the floor structure 10 of the present embodiment, as shown in FIGS. 1 and 2, a beam 36 provided along the free end portion 14 and supporting the free end portion 14 provides a free end under a static load. The bending of the portion 14 can be reduced.

FIG. 7 which is a plan view of FIG. 6 and a cross-sectional view of BB of FIG. 6 shows an example of a conventional floor structure 60 which reduces the floor vibration of the floor slab 50 by using a TMD (Tuned Mass Damper) 58. Has been done.

The TMD 58 includes a plate-shaped viscoelastic rubber member 62 attached to the lower surface of the floor slab 50 via a flange 66, and a mass body 64 provided on the lower surface of the viscoelastic rubber member 62. It is arranged in the underfloor space 56.

Further, in the TMD 58, the rigidity of the viscoelastic rubber member 62 is set so as to be synchronized with the natural frequency of the floor slab 50. As a result, the vibration of the floor slab 50 can be reduced by resonating the mass body 64 with the vibration of the floor slab 50 to vibrate it greatly and absorbing the vibration energy of the floor slab 50.

When the floor vibration of the floor slab 50 is reduced by using the TMD 58 as in the floor structure 60, the TMD 58 is installed near the central portion 54 of the floor where the amplitude of the floor vibration of the floor slab 50 is the largest in the vibration mode of the floor slab 50. However, the amount of static deflection of the floor slab 50 increases as the load is placed near the central portion 54 of the floor. Therefore, the rigidity of the floor slab 50 must be increased by increasing the structural cross section of the floor slab 50 and the beams 28 and 30.

The area of the floor slab 50 increases as the span increases, and the weight (effective weight) of the vibrating floor slab 50 increases. Therefore, the floor vibration of the floor slab 50 cannot be effectively reduced unless the weight of the mass body 64 of the TMD 58 is increased. However, if the weight of the mass body 64 of the TMD 58 is increased, the amount of static deflection of the floor slab 50 increases, so that the rigidity of the floor slab 50 must be further increased.

Further, if the weight of the mass body 64 is increased, the size of the mass body 64 is also increased, so that there is a concern that the TMD 58 cannot be accommodated in the underfloor space 56, and further, the TMD 58 should not fall from the floor slab 50. , TMD58 must be firmly attached to the floor slab 50.

On the other hand, in the floor structure 10 of the present embodiment, as shown in FIG. 2, a position where the floor slab 12 vibrates significantly in the vibration mode is created on the free end portion 14 side of the floor slab 12, and the free end portion 14 is formed. By connecting the girder 20 that hardly generates vibration in the vibration mode of the floor slab 12 with the viscous damper 16, the floor vibration of the floor slab 12 is efficiently reduced by the viscous damper 16, so that the floor slab 50 or small It is possible to obtain a sufficient effect of reducing the floor vibration of the floor slab 50 without increasing the rigidity of the floor slab 50 by increasing the structural cross section of the beams 28 and 30.

Further, when the floor vibration of the floor slab 50 is reduced by using the TMD 58 as in the floor structure 60, if the natural frequency of the TMD 58 deviates from the natural frequency of the floor slab 50, the effect of reducing the floor vibration is greatly reduced. Resulting in.

In particular, the load weight of floor slabs in plazas, such as event plazas, where many people come and go and event equipment is replaced, is large. Therefore, there is a concern that the natural frequency of the floor slab 50 will fluctuate and will be inconsistent with the natural frequency of the TMD 58.

On the other hand, in the floor structure 10 of the present embodiment, as shown in FIG. 2, in the vibration mode as the vibration damping target, the locations (column 18 and free end portion 14) where the displacement difference between the members is large are viscous. By connecting with the system damper 16, the floor vibration of the floor slab 12 is efficiently reduced. Therefore, unlike the floor structure 60 of FIG. 6, the floor slab 12 is affected by the fluctuation of the natural frequency of the vibration mode targeted for vibration suppression. The effect of reducing floor vibration is not significantly reduced.

Here, the result of verifying the floor vibration reduction effect of the floor structure 10 of the present embodiment by using a numerical simulation will be described.

The perspective view of FIG. 8 shows a floor slab 70, which is a model of a large-span floor with a length of 27 m and a width of 27 m, assuming an event plaza space of a large commercial facility.

The floor slab 70 has a thickness of 150 mm and a rigidity proportional damping with a primary damping constant of 2%. Further, the floor slab 70 is supported by a beam 72 made of H-shaped steel (H-1000 × 400 × 19 × 36), whereby all of the peripheral portions 22, 24, 26 and 34 become fixed ends. ing.

As shown in the perspective view of FIG. 9, the primary vibration mode type 74 of the floor slab 70 obtained by numerical simulation has a shape in which the central portion 76 of the floor slab 70 is raised (vibrates most). The primary frequency at this time is 5.4 Hz.

The perspective view of FIG. 10 shows a floor slab 78 as a model in which the peripheral edge portion 34 of the floor slab 70 shown in FIG. 8 is a free end. Other configurations are the same as the floor slab 70.

As shown in the perspective view of FIG. 11, in the primary vibration mode type 80 of the floor slab 78 obtained by numerical simulation, the vicinity of the central portion 82 in the span direction of the peripheral portion 34 of the floor slab 78 is raised (vibrates most). It has a shape. The primary frequency at this time is 4.4 Hz.

The perspective view of FIG. 12 shows a floor slab 84 as a model in which the damping damper 86 is installed near the central portion 82 in the span direction of the peripheral portion 34 (free end) of the floor slab 78 shown in FIG. There is. Other configurations are the same as the floor slab 78. Further, it is assumed that the vibration damping damper 86 has a linear characteristic with a damping coefficient C = 300 N · s / mm.

The graph of FIG. 13 shows the point where the primary mode shape is the largest in each model of the floor slab 70 and the floor slab 84 (the central portion 76 of the floor slab 70 and the peripheral portion 34 of the floor slab 84 in the span direction central portion 82). The values 88 and 90 of the gain (vertical axis) of the transfer function of the displacement with respect to the frequency (horizontal axis) of the floor slabs 70 and 84 at the same position when the force is applied in the vertical direction (near) are shown. The value of the floor slab 70 is set to 88, and the value of the floor slab 84 is set to 90.

From these values 88 and 90, the peak value of the gain of the transfer function is reduced by about 30% in the model of the floor slab 84 based on the floor structure 10 of the present embodiment as compared with the model of the floor slab 70 which is the conventional floor. You can see that there is.

The embodiment of the present invention has been described above.

In the present embodiment, as shown in FIG. 3, an example in which the damping damper is a viscous damper 16 is shown, but the damping damper is connected to the free end portion 14 of the floor slab 12 and the support structure. Any damper that can add damping with is sufficient. For example, the vibration damping damper may be a viscous damper, a viscoelastic damper, a superplastic zinc-aluminum alloy vibration damping damper, or a friction damper. The side view of FIG. 14 shows an example in which the vibration damping damper is a viscous damper 92, and the side view of FIG. 15 shows an example in which the vibration damping damper is a viscoelastic damper 94.

In the floor structure 10 of the present embodiment, since the free end portion 14 of the floor slab 12 and the support structure are connected by a vibration damping damper, the orientation 68 of the viscous damper 92 (viscous damper) is as shown in FIG. The viscous damper 92 can be arranged so that the operating direction of the 92) is in the vertical direction. In this way, the damping force of the viscous damper 92 can be more effectively exerted against the floor vibration of the floor slab 12.

Further, in the present embodiment, as shown in FIG. 1, an example in which the free end portion 14 of the floor slab 12 and the girder 20 as a support structure are connected by a viscous damper 16 is shown, but the floor slab 12 is free. The end portion 14 and the support structure may be connected by a vibration damping damper. For example, as in the floor structure 96 shown in the plan view of FIG. 16, the free end portion 14 of the floor slab 12 and the pillar 18 as the support structure May be connected by a viscous damper 16.

Further, in the present embodiment, as shown in FIG. 1, an example in which the free end portion 14 of the floor slab 12 and the girder 20 as a support structure are connected by one viscous damper 16 is shown. As shown in the floor structure 96, a plurality of damping dampers may be connected. In the floor structure 96, the free end portion 14 of the floor slab 12 and the girder 20 as the support structure are connected by two viscous dampers 16, and the free end portion 14 of the floor slab 12 and the column 18 as the support structure are connected. Are connected by two viscous dampers 16.

Further, in the present embodiment, as shown in FIG. 1, an example is shown in which one peripheral edge portion 34 of all the peripheral edges of the floor slab 12 having a rectangular planar shape is a free end portion 14, but the plan view of FIG. 17 is shown. As in the floor structure 98 shown in the above, two opposing peripheral edges 34 and 26 within the entire peripheral edge of the rectangular planar shape floor slab 12 may be used as free ends. That is, two free end portions 14 and 100 may be provided on the floor slab 12 so as to face each other.

In the floor structure 98 of FIG. 17, a slit 102 is formed in the peripheral edge portion 26 of the floor slab 12, whereby the peripheral edge portion 26 becomes the free end portion 100. Further, the free end portion 14 of the floor slab 12 and the girder 20 as the support structure are connected by one viscous damper 16, and the free end portion 100 of the floor slab 12 and the girder 20 as the support structure are one. It is connected by a viscous damper 16. Further, the free end 100 of the floor slab 12 is supported by a beam 36 provided along the free end 100.

In this way, by providing the floor slab 12 with two free end portions 14 and 100, the positions where the floor slab 12 vibrates significantly in the vibration mode can be dispersed to the two free end portions 14 and 100. .. This makes it possible to use a vibration damping damper with a small damping force.

Further, in the present embodiment, as shown in FIGS. 1 and 2, an example in which a beam 36 for supporting the free end portion 14 is provided along the free end portion 14 is shown, but it is free under a static load. The beam 36 may be omitted if the deflection of the end 14 is not a problem.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and it is needless to say that the present invention can be implemented in various modes without departing from the gist of the present invention.

10, 96, 98 Floor structure 12 Floor slab (floor part)
14,100 Free end 16,92 Viscous damper (vibration damping damper)
20 girder (support structure)
36 beam (beam)
94 Viscoelastic damper (vibration damping damper)

Claims (3)

A rectangular flat floor whose periphery is supported by a support structure composed of columns and beams,
A free end portion provided by cutting an edge between the floor portion and the support structure on a peripheral edge portion forming one side of the peripheral edge of the floor portion
A vibration dampers to reduce the vertical vibration for generating said free end portion and said support structure joint technique the free end portion,
Floor structure with. The floor structure according to claim 1, wherein the free ends are provided so as to face each other. The floor structure according to claim 1 or 2, which has a beam provided along the free end and supports the free end.

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