JP2010242426A - Double floor structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double floor structure which can efficiently attenuate vibration in the vertical direction by a damping member such as a viscoelastic damper and which can improve a degree of freedom in the arrangement position of the damping member. <P>SOLUTION: The double floor structure is placed on top of the floor slab of a building frame and is provided with a lattice beam and the damping member. The lattice beam has a plurality of girders and a plurality of beams. The plurality of girders are supported horizontally on top of the floor slab through the medium of a support member, and the plurality of beams are constructed horizontally between the girders opposed to each other. The damping member attenuates the vibration of the lattice beam in the vertical direction. One end of the damping member is connected to the beam so that the damping member can attenuate the vibration of the lattice beam in the vertical direction through the medium of the beam, and the other end of the damping member is connected to the part other than the lattice beam. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a double floor structure used in a semiconductor factory or the like.

  In precision production factories such as semiconductor factories, severe conditions are imposed on daily fine vibrations. In such a factory, steel structures that are often adopted from the viewpoints of cost, construction period, etc., are caused by vibrations generated by the semiconductor production equipment itself or by walking of workers engaged in manufacturing. May interfere with manufacturing. In particular, since vertical vibration often becomes a problem, various techniques have been proposed to reduce this vertical vibration.

  For example, Patent Document 1 proposes a double floor structure 1 (see, for example, FIG. 8). Specifically, (1) a support member 8 including a column 8 and a brace 81 (or an intermediary column 82) is provided as a vertical surface on the floor slab 25 of the building frame, and (2) the girder 4 is supported by the support member 8 In addition, a plurality of small beams 5 are horizontally installed between the opposing large beams 4 and 4 to form a lattice beam 2 as a horizontal construction surface. (3) A floor panel 6 is installed on the lattice beam 2. The construction of a double floor structure 1 is described. A viscoelastic damper 10a is interposed as a damping member between the braces 81 (or the studs 82) of the support member 8 constituting the vertical construction surface and the large beams 4 of the lattice beam 2 constituting the horizontal construction surface. Thus, the fine vibration in the vertical direction of the lattice beam 2 can be effectively reduced.

JP 2007-270604 A

  However, depending on the installation positions of various facilities and pipes in the factory, there may be a situation where it is difficult to provide the braces 81 and the studs 82 in the support member 8 that is the vertical surface for supporting the girder 4. In that case, it is difficult to provide the viscoelastic damper 10 a for the double floor structure 1.

  The present invention has been made in view of the above-described conventional problems, and in a double floor structure in which vertical vibration can be efficiently damped by a damping member such as a viscoelastic damper, the position of the damping member is determined. The purpose is to increase the degree of freedom.

In order to achieve this object, the invention shown in claim 1
It is a double floor structure installed at the top of the floor slab of the building frame,
A plurality of large beams supported horizontally via a support member above the floor slab, and a lattice beam having a plurality of small beams laid horizontally between the opposed large beams;
A damping member that damps the vertical vibration of the lattice beam,
One end of the damping member is connected to the small beam so that the damping member attenuates vibration in the vertical direction of the lattice beam via the small beam, and the other end of the damping member is And connected to a portion other than the lattice beam.

According to the first aspect of the present invention, the damping member is provided on the small beam in the lattice beam, and the vertical vibration of the lattice beam is attenuated through vibration attenuation of the small beam. Therefore, it is not necessary to provide the damping member on the girder, that is, it is released from the constraint that the damping member is provided on the girder. Thereby, the freedom degree of the arrangement position of an attenuation member can be raised.
Moreover, since the lattice beam has a lattice shape, it has high rigidity as a whole. Therefore, the damping force applied from the damping member to the small beam can be reliably transmitted to the entire lattice beam through the small beam, and as a result, the vertical vibration of the entire lattice beam can be effectively reduced.
Furthermore, since the dampening member is provided in the small beam, the dampening member can be arranged at almost any position in the plane of the lattice beam. Therefore, the damping member can be selectively and reliably arranged with respect to a position where the vertical vibration occurs in the plane of the lattice beam and its vicinity, and as a result, the vibration environment in the vertical direction of the lattice beam can be freely controlled. .

The invention shown in claim 2 is the double floor structure according to claim 1,
The other end of the damping member is connected to the floor slab or the support member via a connecting member.
According to the second aspect of the present invention, the other end of the damping member is connected to the floor slab or the support member. Accordingly, a reaction force for attenuating the vertical vibration of the lattice beam can be reliably taken from the floor slab or the support member, and as a result, the vertical vibration of the lattice beam can be effectively attenuated.

The invention described in claim 3 is the double floor structure according to claim 2,
The connection member is a triangular truss structure or a ramen structure.
According to the third aspect of the present invention, the connecting member is a triangular truss structure or a ramen structure. Therefore, it is possible to reliably prevent vertical deformation of the connecting member itself, which may occur when vertical vibration is input to the damping member, and as a result, the lattice beam beam is not substantially affected by the deformation of the connecting member. It is possible to accurately input the vertical vibrations to the damping member. Therefore, the damping member can exhibit the designed damping performance.

Invention of Claim 4 is a double floor structure in any one of Claims 1 thru | or 3, Comprising:
The one end portion of the damping member is connected to the beam at the intersection of the beam beams intersecting each other of the lattice beam.
According to the fourth aspect of the present invention, the damping member is connected to the intersection of the beam and the beam that intersect each other. Therefore, the damping force of the damping member can be quickly transmitted in both directions intersecting each other in the plane of the lattice beam, and the vertical vibration of the entire lattice beam can be effectively reduced.
In addition, since the crossing point is higher in rigidity than the portion of only the small beam, the damping force applied to the crossing point can be reliably transmitted to the lattice beam, and thus the vibration in the vertical direction of the lattice beam is high. Attenuation is possible with attenuation.

Invention of Claim 5 is the double floor structure in any one of Claims 1 thru | or 4, Comprising:
The damping member has attachment portions at the one end and the other end, respectively.
The damping member is at least one attachment portion of the attachment portion of the small beam to which the attachment portion of the one end portion is attached or the attachment portion of the portion other than the lattice beam to which the attachment portion of the other end portion is attached. It is slidably attached to the mounting surface of the
A holding member for holding the one mounting portion and the mounting portion for the damping member in contact with each other on the surface opposite to the mounting surface and sandwiching the mounting portions;
The friction coefficient related to the horizontal friction force between the sandwiching member and the one attachment portion is different from the friction coefficient related to the horizontal friction force between the sandwiching member and the attachment portion of the damping member. It is characterized by that.

According to the fifth aspect of the present invention, it is possible to achieve fail-safe prevention that prevents damage to the damping member due to an earthquake and maintenance-free that is freed from any recovery work related to the damping member after the earthquake.
In other words, when a horizontal force is applied to the double floor structure during an earthquake, the damping member slides against the one mounting portion, which greatly increases the horizontal force input to the damping member. It is reduced. As a result, damage to the damping member is effectively prevented.

  Further, at the time of this sliding, the sandwiching member is attached to the one with the larger friction coefficient among the one attachment part and the damping member on the basis of the friction coefficient difference described above, and with respect to the smaller friction coefficient. Will slide quickly. That is, the sandwiching member quickly slides according to the sliding between the one attachment portion and the damping member while maintaining the sandwiched posture. Therefore, it is possible to effectively prevent the sandwiching member from dropping from the mounting portion or the sandwiching member from being deformed, and it is possible to eliminate the work of re-installing the sandwiching member after the earthquake.

Invention of Claim 6 is the double floor structure of Claim 5,
The one attachment part is wider in the horizontal direction than the attachment part of the damping member,
The coefficient of friction related to the frictional force in the horizontal direction between the sandwiching member and the mounting part of the damping member is larger than the coefficient of friction related to the frictional force in the horizontal direction between the sandwiching member and the one mounting part. Is large.

According to the sixth aspect of the present invention, when the damping member slides in the horizontal direction with respect to the one attachment portion, the sandwiching member has a friction coefficient based on the friction coefficient difference. It follows the large damping member and quickly slides with respect to the one attachment portion having a small friction coefficient. Therefore, it is possible to effectively prevent the sandwiching member from dropping from the attachment portion of the attenuation member.
Further, since the one attachment portion is wider in the horizontal direction than the attachment portion of the damping member, even if the sandwiching member slides with respect to the one attachment portion, the one attachment portion will fall off. hard.
As described above, it is possible to reliably prevent the sandwiching member from falling off from the attachment portion of the attenuation member and the attachment portion of the construction surface.

The invention shown in claim 7 is the double floor structure according to claim 5 or 6,
The sandwiching member has a pair of sandwiching portions opposed to each other with a gap between them at both ends of the U-shaped or C-shaped member, and at least one of the pair of sandwiching portions serves as the other sandwiching portion. In contrast, the clamp is provided so as to be able to advance and retreat.
According to the seventh aspect of the present invention, since the sandwiching member is a U-shaped or C-shaped clamp, even when the attenuation member is already fastened and fixed to the one attachment portion, the attenuation member is Therefore, the damping member can be easily changed to a maintenance-free damping member having a fail-safe function.

  For example, an existing bolt that fastens and fixes the one attachment portion and the attachment portion of the damping member is removed, and instead, the clamp is attached to the attachment portion side by using a distance between a pair of clamping portions of the clamp. If it inserts from the direction, a clamp can be easily arrange | positioned in the position which can pinch | interpose the said attaching part. That is, the clamping member as a clamp can be installed in the mounting portion without any problem. As a result, the existing damping member can be easily changed to a damping member that is maintenance-free and has a fail-safe function.

  ADVANTAGE OF THE INVENTION According to this invention, the freedom degree of the arrangement position of a damping member can be raised in the double floor structure which can attenuate | dampen a vibration of a perpendicular direction efficiently by damping members, such as a viscoelastic damper.

It is a schematic plan view which shows the whole double floor structure 1 which concerns on this embodiment. It is a schematic perspective view which shows a part of FIG. It is explanatory drawing of an example of the joining structure of the cross beam 5 spanned vertically and horizontally, FIG. 3A shows the top view of the lattice beam 2, and FIG. 3B shows the perspective view which looked at the lattice beam 2 from the bottom. Show. It is a schematic perspective view of the double floor structure 2 which provided the supporting member 8 of the other form. FIG. 5A is a side view of the viscoelastic damper 10a, and FIG. 5B is a BB arrow view in FIG. 5A. FIG. 10 is a schematic perspective view of a first modification of the connecting member 91 of the damping means 10. It is a schematic perspective view of the 2nd modification of the connection member 93 of the attenuation means 10. FIG. It is a schematic perspective view of the example of installation of the viscoelastic damper 10a to the girder 4. It is the schematic diagram which looked at the double floor structure 1 which concerns on this embodiment from the side. 10A is a side view of the attachment structure of the viscoelastic damper 10a, and FIG. 10B is a cross-sectional view taken along the line BB in FIG. 10A. FIG. 11A is a side view of a preferred mounting structure example, and FIG. 11B is a cross-sectional view taken along line BB in FIG. 11A. 12A is a side view of a modified example of the attachment structure of the viscoelastic damper 10a, and FIG. 12B is a cross-sectional view taken along the line BB in FIG. 12A.

=== This Embodiment ===
<<< About Double Floor Structure 1 >>>
1 and 2 are explanatory views of the double floor structure 1. FIG. FIG. 1 is a schematic plan view showing the entire double floor structure 1, and FIG. 2 is a schematic perspective view showing a part of FIG.

  The double floor structure 1 is applied to, for example, a clean room of a precision production factory. That is, the double floor structure 1 is configured by using the floor slab 25 of the factory building frame as a lower floor and arranging the upper floor 21 on the floor slab 25. Various precision devices and production facilities are installed on the floor surface of the upper floor 21, while the space SP between the floor surface of the upper floor 21 and the floor slab 25 is connected to wiring, piping, air conditioning. Used for circulation, equipment delivery, etc.

  The upper floor 21 includes a lattice beam 2 that is horizontally installed above the floor slab 25 at a predetermined interval, a support member 8 that is vertically installed on the floor slab 25 and supports the lattice beam 2, and a lattice A floor panel 6 placed on the beam 2 and a damping means 10 for damping the vertical vibration of the lattice beam 2 are provided.

  The lattice beam 2 includes a large beam 4 and a small beam 5. The girder 4 is made of, for example, H-shaped steel, and is installed vertically and horizontally at a predetermined interval above the floor slab 25, thereby partitioning the upper part of the floor slab 25 into a lattice shape. In this example, the vertical beam 4 (hereinafter also referred to as the vertical beam 4L) and the horizontal beam 4 (hereinafter also referred to as the horizontal beam 4C) intersecting each other are orthogonal to each other. Each opening shape of the lattice is rectangular.

  On the other hand, the small beam 5 is made of, for example, H-shaped steel having a small cross section having a smaller section modulus than the large beam 4. And it spans horizontally and vertically between the big beams 4 and 4 which oppose each other, and each opening of the lattice is further finely partitioned. Here, the small beam 5 (hereinafter also referred to as the vertical beam 5L) spanned in the vertical direction is arranged in parallel to the vertical beam 4L, and the small beam 5 (hereinafter referred to as the horizontal beam) spanned in the horizontal direction. The direction small beam 5C) is arranged in parallel to the horizontal large beam 4C. Therefore, each opening shape of the lattice subdivided by these small beams 5, 5... Is also rectangular.

  FIG. 3A and FIG. 3B are explanatory diagrams of an example of a joint structure of the small beams 5 that are stretched vertically and horizontally. As shown in the plan view of FIG. 3A, the vertical small beam 5L is bridged between the horizontal large beams 4C and 4C. On the other hand, both ends in the longitudinal direction of the transverse beam 5C are bridged between the longitudinal beam 4L and the longitudinal beam 5L, or between the longitudinal beams 5L and 5L. . Here, the latter will be described in detail. As shown in a perspective view seen from below in FIG. 3B, the longitudinal beam 5L (or the longitudinal beam 4L not shown) with which the end face of the small beam 5C is abutted is shown. A rib plate 5r protruding sideways from the web 5Lw is integrally fixed to the web 5Lw by welding or the like. Then, the rib plate 5r and the web 5Cw of the lateral beam 5C are abutted with each other, and the connecting plate 5j is fastened and fixed with bolts across the webs 5Cw extending over the rib plates 5r, whereby the web 5Lw, 5Cw is joined. On the other hand, for joining the flanges 5Lf and 5Cf, the flange 5Cf of the transverse beam 5C is abutted from the side to the flange 5Lf of the longitudinal beam 5L (or the longitudinal beam 4L (not shown)) by welding or the like. Be joined. Such a joint structure is also used for joining the longitudinal large beam 4L and the transverse large beam 4C and joining the longitudinal small beam 5L and the transverse large beam 4C. However, the joining structure is not limited to the above as long as members orthogonal to each other can be joined.

  As shown in FIGS. 1 and 2, the support member 8 includes a pillar 8 such as H-shaped steel that supports the large beam 4 as a main material. Each column 8 is erected vertically on a portion of the floor slab 25 corresponding to the intersection of the large beams 4 and 4 orthogonal to each other, and supports the large beam 4 at the intersection. The support member 8 may have auxiliary members such as braces 8a and inter-columns 8b in addition to the columns 8 in order to increase the rigidity of the support members 8. For example, as shown in FIG. 4, a truss structure may be formed by connecting a lower end portion of the column 8 and an intermediate portion of the large beam 4 supported by the column 8 by using a brace 8 a. As described above, an intermediate column 8b may be provided in the middle portion of the large beam 4 to supplement the support rigidity of the column 8.

  As shown in FIG. 2, the floor panel 6 is a rectangular plate, for example, and is horizontally placed and fixed on the upper portions of the large beam 4 and the small beam 5. Note that a joist (not shown) may be interposed between at least one of the large beam 4 and the small beam 5 and the floor panel 6 as necessary.

  As shown in FIG. 2, the damping means 10 is a viscoelastic damper 10 a (corresponding to a “damping member”) connected to the beam 5 and a connecting member for connecting the viscoelastic damper 10 a to the floor slab 25. And a stud 9. Here, the stud 9 is made of, for example, H-shaped steel as a main material, and stands vertically on a portion of the upper surface of the floor slab 25 that faces directly below an intersection CP (hereinafter also referred to as an intersection CP) between the small beams 5 and 5. It is installed. As a result, the viscoelastic damper 10a is interposed between the portion of the intersection CP of the small beam 5 and the upper end of the inter-column 9, and thus the viscoelastic damper 10a has a vertical reaction force related to vibration damping. Obtained from the floor slab 25, the vertical vibration of the lattice beam 2 is attenuated through the attenuation of the vertical vibration of the small beam 5.

  Further, here, the viscoelastic damper 10a is connected to an intersection CP between the small beam 5 and the small beam 5 orthogonal to each other. Therefore, the damping force of the viscoelastic damper 10a can be quickly transmitted in the vertical and horizontal directions orthogonal to each other in the plane of the lattice beam 2, and the vertical vibration of the entire lattice beam 2 can be effectively reduced.

  Incidentally, in the example of FIG. 2, among the plurality of intersection points CP, CP... Of the minimum unit lattice beam 2m surrounded by four large beams 4, 4, 4, 4 in total, the minimum A viscoelastic damper 10a is provided at the intersection CP of the plane center of the unit lattice beam 2m or the position closest thereto. And the intersection CP of the said position is a position which tends to become an antinode of a vertical vibration generally. Therefore, the vertical vibration of the minimum unit lattice beam 2m is most effectively damped by the viscoelastic damper 10a disposed at the position.

  5A and 5B are detailed explanatory views of the viscoelastic damper 10a. FIG. 5A is a side view, and FIG. 5B is a BB arrow view in FIG. 5A.

  The viscoelastic damper 10a is connected to an upper member 11 (corresponding to “one end portion of the damping member”) connected to the small beam 5 side and a lower member 14 (“other end portion of the damping member”) connected to the stud 9 side. And a viscoelastic body 17 interposed between the upper member 11 and the lower member 14, and the upper member 11 and the lower member 14 are arranged in the vertical direction and the small beam via the viscoelastic body 17. 5 is configured to be relatively displaceable in the longitudinal direction.

  The upper member 11 is erected vertically on a horizontal attachment plate 12 (hereinafter also referred to as an upper attachment plate 12) as an attachment portion to the beam 5 and on the lower surface side of the upper attachment plate 12, and And a plurality of vertical plates 13, 13... (Three in the illustrated example) arranged with a predetermined gap therebetween. On the other hand, the lower member 14 is also erected vertically on a horizontal attachment plate 15 (hereinafter also referred to as a lower attachment plate 15) as an attachment portion to the stud 9 and on the upper surface side of the lower attachment plate 15. , And a plurality of vertical plates 16, 16... (Two in the illustrated example) inserted into the gaps between the vertical plates 13, 13 of the upper member 11, respectively. In each gap S between the plate surface of the vertical plate 16 and the plate surface of the vertical plate 13 facing each other, a viscoelastic body 17 is provided integrally with these plate surfaces.

  Therefore, for example, an excitation force is input to the grid beam 2 by operating various production facilities installed on the grid beam 2 via the floor panel 6 or walking of an operator on the grid beam 2, Even when a vertical vibration is generated in 2, the vertical vibration is effectively damped by the damping characteristic of the viscoelastic body 17 related to the viscoelastic damper 10 a. That is, the vibration amplitude at the natural frequency of the lattice beam 2 is not amplified, and the amplification of the vibration amplitude in the vertical direction (decrease in dynamic rigidity) is effectively suppressed. As a result, it is possible to reduce the adverse effects that the precision instruments on the lattice beam 2 can be affected by their own vertical vibrations, and to fully exhibit their performance.

  Further, according to the configuration in which the damping means 10 is connected to the beam 5 and the damping force is input to the beam 5 as described above, the beam 5 extends over most of the area in the plane related to the lattice beam 2. Since it is arranged in a wide range like a mesh, the attenuation means 10 can be arranged at an arbitrary position in the plane of the lattice beam 2 via the small beam 5. Therefore, the damping means 10 can be selectively and reliably disposed at a position (position where vibration amplitude is large) that can become an antinode of vertical vibration in the plane of the lattice beam 2 or a position near the position. The vibration environment in the vertical direction can be freely controlled.

  For example, the vibration environment on the lattice beam 2 changes according to the layout of various production facilities placed on the lattice beam 2 after the lattice beam 2 is completed. Therefore, after actually measuring the vibration of the grid beam 2 at each position while the factory is in operation, the position where the vibration amplitude in the plane of the grid beam 2 should be reduced is specified based on the actual measurement result, and the selected position is selected. If the damping means 10 is disposed later, an optimal vibration environment according to the usage pattern of the double floor structure 1 can be created. That is, the vibration environment of the double floor structure 1 can be easily customized according to the usage form.

  Incidentally, from the viewpoint of improving the damping efficiency of the vertical vibration of the viscoelastic damper 10a of the damping means 10, it is desirable that the intermediate column 9 as the connecting member is not designed to bear a long-term load or a short-term load excluding its own weight in design. It is good to do so. That is, it is preferable not to support the self-weight of the lattice beam 2, and in this way, only the external force accompanying the vertical vibration of the small beam 5 is generally input to the viscoelastic damper 10 a, so that the vertical Vibration can be damped efficiently.

  6 and 7 show modifications of the connecting member of the damping means 10. In the first modification of FIG. 6, a triangular truss structure 91 is used as a connecting member instead of the stud 9. Specifically, this truss structure 91 is a structure in which the pillar 8 supporting the large beam 4 and the two diagonal members 91a and 91b are assembled in a triangle and their joints are connected by pin connection such as bolting. is there.

  For example, in the illustrated example, one end portion of the corresponding diagonal members 91a and 91b is connected and fixed to the upper end portion of the column 8 and the middle portion of the column 8 by bolts, and the diagonal members 91a and 91b are respectively The viscoelastic damper 10a is extended directly below the intersection CP of the target beam 5 and the other ends of the diagonal members 91a and 91b are connected and fixed by bolts. A bracket (not shown) having a horizontal upper surface is fixed to the upper portion of the other end portion connected and fixed, and the lower surface of the lower mounting plate 15 of the viscoelastic damper 10a described above is fixed to the upper surface of the bracket. It is closely attached and fastened and fixed with bolts. The upper mounting plate 12 of the viscoelastic damper 10a is in close contact with the lower surface portion of the small beam 5 directly below the intersection CP, and is fastened and fixed by bolts, as described above.

  And according to this 1st modification, since the truss structure 91 is used as a connection member, compared with the cantilever support which consists only of one diagonal material, the rigidity of the perpendicular direction of a connection member can be raised significantly. As a result, the viscoelastic damper 10a can be reliably supported in the vertical direction. As a result, the viscoelastic damper 10a can reliably take the vertical reaction force related to vibration damping from the floor slab 25, and as a result, it is possible to reliably exhibit a high damping capability with respect to the vertical vibration of the lattice beam 2. .

  In this first modification, one end portion of the diagonal member 91a is connected to the middle portion of the column 8, but may be connected to the lower end portion of the column 8, and further, the lower end portion of the column 8. It may be connected to the portion of the floor slab 25 adjacent to.

  Further, even if the three nodes of the column 8 and the two diagonal members 91a and 91b are connected by rigid joining such as welding, and the connecting member is configured as a ramen structure, the same effect can be obtained. Can do.

  On the other hand, the connecting member of the second modified example in FIG. 7 is in the form of a stud as in the above-described embodiment, but the stud 93 is not a single material made of only H-shaped steel but a plurality of members 93a and 93b. A truss structure. For example, the stud 93 includes a pair of diagonal members 93a and 93b that are assembled in an inverted V shape and have a lower end fixed to the upper surface of the floor slab 25. The pair of diagonal members 93a and 93b and the floor slab The upper surface 25s of 25 forms a truss structure. In addition, it is the same as the above-mentioned that you may comprise the said studs 93 with a ramen structure.

  By the way, the installation location of the viscoelastic damper 10a in the lattice beam 2 is not limited to one location as in the example of FIG. 2, but at a plurality of locations in the plane of the lattice beam 2 as in the example of FIG. May be installed. That is, in the example of FIG. 6, each of the positions of four points which are point-symmetric with respect to the plane center of the lattice beam 2m of the smallest unit surrounded by four large beams 4, 4, 4 and 4 is in each case. An elastic damper 10a is provided. As a result, the vertical vibration of the lattice beam 2m of the minimum unit is damped most effectively.

  Moreover, the installation site | part of the viscoelastic damper 10a in the small beam 5 is not restricted to the above-mentioned intersection CP at all, The arbitrary site | part in the small beam 5 can be selected according to the vibration condition of the double floor structure 1. FIG. For example, the upper surface of the upper mounting plate 12 of the viscoelastic damper 10a may be tightly fixed to the lower surface of the beam portion of the small beam 5, that is, the lower surface of the portion of the small beam 5 positioned between the intersection points CP. .

  In addition to the viscoelastic damper 10a of the small beam 5 described above, a viscoelastic damper 10a may be separately provided for the large beam 4. As an example of installation of the viscoelastic damper 10a on the girder 4, FIG. 8 can be illustrated. That is, in this example, the support member 8 has an inverted V-shaped brace 81 that is laid between the columns 8 and 8 that support the same large beam 4 in addition to the columns 8 that support the large beam 4. A viscoelastic damper 10a is interposed between the top of the inverted V-shaped brace 81 and the large beam 4. Further, in this example, a stud 82 is erected directly below the middle portion of the large beam 4, and a viscoelastic damper 10 a is interposed between the stud 82 and the large beam 4.

<< About fail-safe and maintenance-free viscoelastic damper 10a >>
By the way, the reason why the viscoelastic body 17 shown in FIG. 5B is layered to reduce the thickness in the double floor structure 1 described above is to improve the damping performance against micro vibrations. That is, by reducing the thickness of the viscoelastic body 17, a large shear strain (= the amount of deformation in the direction perpendicular to the thickness direction of the viscoelastic body / the thickness of the viscoelastic body) is generated even in a minute displacement. Thus, a large damping force is generated even under a slight vibration.

  However, when the thickness of the viscoelastic body 17 is reduced, the shear strain increases even with a small displacement as described above. In other words, when the thickness of the viscoelastic body 17 is reduced, the limit displacement corresponding to the limit shear strain of the viscoelastic body 17 is reduced. For example, when the limit shear strain of the viscoelastic body 17 is α × 100% and the design thickness of the viscoelastic body 17 capable of effectively suppressing micro vibrations is as thin as β mm, the limit of the viscoelastic body 17 The displacement is a small value of several centimeters (= α × β mm).

  On the other hand, the double floor structure 1 is also required to have seismic soundness against a large earthquake. Then, in the case of this large earthquake, a ground vibration having a horizontal amplitude exceeding several centimeters is assumed, and in this case, there is a possibility that the ground vibration having a horizontal amplitude may be input to the viscoelastic damper 10a as it is.

  FIG. 9 is an explanatory diagram showing the double floor structure 1 in a side view. For example, the double floor structure 1 is deformed in the horizontal direction from the state indicated by the two-dot chain line in FIG. 9 to the state indicated by the solid line in FIG. 9, that is, the small beam 5 of the lattice beam 2 is greatly displaced in the horizontal direction. On the other hand, the intermediate column 9 of the damping means 10 is not so deformed. Therefore, a difference in the amount of displacement in the horizontal direction is generated between the small beam 5 and the upper end of the intermediary column 9 serving as the connecting member, and the difference in the amount of displacement is input to the viscoelastic damper 10a. That is, there is a possibility that the horizontal ground motion exceeding the above-mentioned several centimeters may be input to the viscoelastic damper 10a in almost the same size, in which case it exceeds the limit shear strain of the viscoelastic body 17, The viscoelastic damper 10a is damaged.

  Therefore, in this double floor structure 1, the following device is devised with respect to the attachment structure of the viscoelastic damper 10a, thereby providing a fail-safe function so that the viscoelastic damper 10a is not damaged even in the event of a large earthquake. I have it. In addition to this, maintenance-free operation is also made so that no restoration work related to the viscoelastic damper 10a is required after the earthquake.

  10A and 10B are explanatory diagrams of the attachment structure of the viscoelastic damper 10a. 10A is a side view, and FIG. 10B is a cross-sectional view taken along line BB in FIG. 10A.

  The viscoelastic damper 10a is interposed between the intersection point CP of the small beam 5 and the upper end of the intermediary column 9 which is the connecting member and is disposed immediately below the intersection point CP. Specifically, the small beam 5 is arranged with a pair of flanges 5f, 5f of the H-shaped steel positioned vertically. A plate 9c having a predetermined thickness (hereinafter also referred to as an inter-column upper end plate 9c) is abutted and fixed to the upper end of the inter-column 9 in an integrated manner. Therefore, the upper mounting plate 12 of the viscoelastic damper 10a can be mounted with the horizontal lower surface 5d of the lower flange 5f of the small beam 5 (corresponding to the “beam mounting portion”) as the mounting surface on the small beam 5 side. The lower mounting plate 15 of the elastic damper 10a is mounted with the horizontal upper surface 9d of the inter-column upper end plate 9c (corresponding to “one mounting portion”) as the mounting surface on the inter-column 9 side.

  At this time, the horizontal mounting surface 12d of the upper mounting plate 12 of the viscoelastic damper 10a and the horizontal mounting surface 5d of the lower flange 5f of the small beam 5 need to be in close contact with each other, The horizontal mounting surface 15d of the lower mounting plate 15 of the viscoelastic damper 10a and the horizontal mounting surface 9d of the stud upper end plate 9c also need to be in close contact over substantially the entire surface. This is because the fine vibration in the vertical direction of the lattice beam 2 is surely transmitted to the intermediary column 9 which is the connecting member via the viscoelastic damper 10a and reliably attenuated by the viscoelastic damper 10a. That is, this is to increase the vertical dynamic rigidity of the lattice beam 2.

  Here, for the former contact, that is, the contact between the attachment surface 5d of the lower flange 5f of the small beam 5 and the attachment surface 12d of the upper attachment plate 12 of the viscoelastic damper 10a, for example, a fastening bolt 40 is used. Specifically, the fastening bolt 40 is provided by passing both the lower flange 5f of the small beam 5 and the upper mounting plate 12 of the viscoelastic damper 10a in the vertical direction, and the nut 41 that is screwed to the fastening bolt 40 is fastened. Due to the force, the lower flange 5f and the upper mounting plate 12 are fixed so as not to move relative to each other in the vertical direction and the horizontal direction in a close contact state in which the mounting surfaces 5d and 12d are overlapped. In this example, a plurality of fastening bolts 40 (four in this case) are provided side by side in the longitudinal direction of the small beam 5 to form a fastening bolt row. For example, two rows are provided across the H-shaped steel web 5w, but the arrangement is not limited to this example.

  On the other hand, the clamp 50 (corresponding to the “pinching member”) is used for the latter contact, that is, the contact between the attachment surface 15d of the lower attachment plate 15 of the viscoelastic damper 10a and the attachment surface 9d of the stud upper plate 9c. The clamp 50 has a U-shaped or C-shaped member as a main body, and jack bolts 51 and 51 serving as sandwiching portions are screwed into both end portions 50a and 50a so as to be able to advance and retreat toward the opposite end portions 50a, respectively. Are combined. Therefore, in a state where both the lower mounting plate 15 of the viscoelastic damper 10a and the upper end plate 9c of the stud are positioned between the jack bolts 51 and 51, the lower mounting of the jack bolt 51 is performed by screwing and rotating. Both the plate 15 and the stud upper plate 9c are sandwiched between jack bolts 51 and 51, and are overlapped and closely attached to each other on the attachment surfaces 15d and 9d.

  Here, the static frictional force F generated between the mounting surfaces 9d and 15d is adjusted so as to satisfy the following expression 1 by adjusting the pinching force of the jack bolts 51 and 51.

Static friction force F <Assumed load of damage of viscoelastic damper−Static friction force f of clamp f Equation 1
In addition, the “assumed damage load” in the above formula 1 is, for example, a load having a magnitude that causes a limit shear strain in the viscoelastic body 17 of the viscoelastic damper 10a. Further, “the static frictional force f of the clamp” in the formula 1 is the horizontal static frictional force f1 between the clamp 50 and the viscoelastic damper 10a and the horizontal frictional force between the clamp 50 and the intermediate post 9. It is the smaller frictional force of the static frictional force f2. Specifically, in the example of FIGS. 10A and 10B, the former static friction force f1 is a static friction force between the tip of the jack bolt 51 and the upper surface 15f of the lower mounting plate 15 of the viscoelastic damper 10a. The static frictional force f2 is the smaller of the static frictional force between the tip of the jack bolt 51 and the sliding member 53 described later or the static frictional force between the sliding member 53 and the lower surface 9f of the inter-column upper end plate 9c. It is the friction force.

  If the static friction force F between the mounting surfaces 9d and 15d is set so as to satisfy the above formula 1, even if a large horizontal force acts on the double floor structure 1 during an earthquake, Before the force more than the assumed damage load acts on the viscoelastic damper 10a, the horizontal sliding between the mounting surfaces 9d and 15d is started, whereby the viscoelastic damper 10a is It will be cut off. As a result, the input of the horizontal force to the viscoelastic damper 10a is suppressed, and the breakage is effectively prevented. That is, a fail safe function is given to the viscoelastic damper 10a. In order to reliably reduce the friction coefficient between the mounting surfaces 9d and 15d, a low friction coefficient such as a fluororesin such as PTFE (polytetrafluoroethylene) (for example, Teflon (registered trademark of DuPont, USA)) is used. A sliding material (not shown) may be interposed between the attachment surfaces 9d and 15d.

  A plurality of (in this case, four) such clamps 50 are provided side by side in the longitudinal direction of the small beam 5 to form a clamp row, and the clamp row is formed on the web 9w of the intermediate column 9 of the H-shaped steel. For example, two rows are provided on both sides, but the arrangement is not limited to this example. Moreover, as a specific example of the clamp 50, a Bullman C type (trade name: manufactured by Bullman Co., Ltd.) or the like can be given.

  By the way, the above-mentioned clamp 50 is attached across both the viscoelastic damper 10a and the intermediate post 9 via a pair of jack bolts 51, 51. On the other hand, at the time of the action of the large horizontal force described above, the viscoelastic damper 10a and the spacer 9 are cut off and relatively moved (slid) in the horizontal direction. Therefore, if the jack bolt 51 of the clamp 50 is firmly fixed to both the viscoelastic damper 10a and the intermediary column 9, the clamp 50 may be connected to the viscoelastic damper 10a and the intermediary column 9 during the relative movement described above. There is a risk that the clamp 50 may be deformed, for example, twisted due to a horizontal tensile force or the like from both, or may fall off from both sides due to competition. As a result, every time an earthquake occurs, re-installation work such as replacement of the clamp 50 is forced after the earthquake, which is inconvenient.

  Therefore, in order to make the clamp 50 maintenance-free, the friction coefficient relating to the horizontal static friction force between the clamp 50 and the viscoelastic damper 10a and the horizontal static friction between the clamp 50 and the intermediate post 9 are obtained. The friction coefficient related to the force is made different. Thereby, at the time of relative movement of the viscoelastic damper 10a and the intermediary column 9, the clamp 50 is attached to one of the viscoelastic damper 10a and the intermediary column 9 based on the above-described friction coefficient difference, and quickly to the other. To slide. As a result, the deformation and dropping of the clamp 50 as described above can be effectively prevented. Incidentally, the reason why the frictional force should be made different directly is that the friction coefficient only needs to be changed instead. The vertical drags that are the basis of each frictional force are the internal forces of the clamp 50 (similar to the axial force). This is because they are equivalent to each other.

  Specific methods for making these friction coefficients different from each other include roughening or roughening the surface, or using a sliding material having a low friction coefficient such as the above-mentioned fluororesin such as PTFE. In the examples of FIGS. 10A and 10B, the latter method is adopted. That is, as shown in FIG. 10A, the front end portion of one jack bolt 51 of the clamp 50 and the lower surface 9f of the inter-column upper plate 9c to which a clamping force is to be applied from the front end portion ("the surface opposite to the mounting surface"). The sliding material 53 is interposed between the tip end of the other jack bolt 51 of the clamp 50 and the viscoelastic damper to which a clamping force is to be applied from the tip end. The sliding material 53 is not interposed between the upper surface 15f of the lower mounting plate 15a (corresponding to the “surface opposite to the mounting surface”) 10a. As a result, the coefficient of friction between the clamp 50 and the viscoelastic damper 10a is set to be larger. As a result, during relative movement between the viscoelastic damper 10a and the intermediary column 9, the clamp 50 maintains the sandwiching posture while maintaining the sandwiching posture. It is securely attached to the elastic damper 10a.

  Incidentally, the reason for attaching to the viscoelastic damper 10a is that, in the example of FIGS. 10A and 10B, the upper surface 15f of the lower mounting plate 15 of the viscoelastic damper 10a is lower than the lower surface 9f of the stud upper end plate 9c. This is because it is narrower in all directions in the horizontal direction. That is, when the jack bolt 51 slides, the probability of dropping from the lower mounting plate 15 of the viscoelastic damper 10a is higher than that of the stud upper end plate 9c.

  Here, preferably, as shown in FIG. 11A and FIG. 11B, between the lower mounting plate 15 of the viscoelastic damper 10a and the tip of the jack bolt 51 facing this, and the sliding material 53, A pressure receiving plate 55 made of a steel plate having a predetermined thickness may be interposed between the tip of the other jack bolt 51 facing the sliding member 53. The pressure receiving plate 55 is provided for each clamp row, and is formed to have a length over all the clamps 50 belonging to the clamp row. If such a pressure receiving plate 55 is provided, the frictional force distribution generated by the clamp row can be made substantially uniform.

  Moreover, according to the structure which provides the above-mentioned pressure receiving plate 55, when making it maintenance-free and fail-safe by retrofitting with respect to the existing viscoelastic damper 10a, the remodeling construction can be performed easily. This will be specifically described with reference to FIGS. 5A and 5B. FIG. 5A and FIG. 5B show an attached state of the existing viscoelastic damper 10a before the fail safe modification. Usually, the lower mounting plate 15 of the existing viscoelastic damper 10a and the stud upper end plate 9c are fastened and fixed by fastening bolts 44. Therefore, the fastening bolts 44 are removed as one work of the remodeling work. Then, bolt holes 15h and 9h appear in the lower mounting plate 15 and the inter-column upper end plate 9c, respectively. Depending on the size of the jack bolt 51 of the clamp 50, the tip end portion of the jack bolt 51 falls into the bolt holes 15h and 9h, thereby obstructing the installation of the clamp 50.

  In this regard, as shown in FIGS. 11A and 11B, the pressure receiving plate 55 is formed in a size that covers and closes the bolt holes 15 h and 9 h, and the pressure receiving plate 55 is connected to the tip of one jack bolt 51. Since the pressure receiving plate 55 prevents the jack bolt 51 from falling if it is interposed between the lower mounting plate 15 and between the tip of the other jack bolt 51 and the sliding member 53, the clamp 50 Installation work can be performed without problems. That is, it is excellent in workability when the viscoelastic damper 10a is made maintenance and made fail-safe later.

  Incidentally, the problem related to the above-described bolt holes 15h and 9h occurs particularly when an interference object is attached to the viscoelastic damper 10a and the installation position of the above-described existing fastening bolt 44 is limited. easy. For example, in the example of FIGS. 5A and 5B, the assembly bolts 19 for assembling a plurality of the vertical plates 16, 16 (two in the illustrated example), which are parts of the viscoelastic damper 10 a, are arranged in the longitudinal direction of the girder 4. Are provided along a predetermined pitch. For this reason, the existing fastening bolts 44 are installed by changing the positions of these assembly bolts 19, but such a restriction on the installation position is similarly imposed on the clamp 50. That is, the clamp 50 must be disposed at the same position as the position where the fastening bolt 44 is removed. Then, the jack bolt 51 of the clamp 50 is likely to fall into the existing bolt holes 15h, 9h, that is, the installation of the clamp 50 is significantly hindered. Therefore, the above-described pressure receiving plate 55 is particularly effective when there is a restriction on the position where the existing fastening bolts 44 can be installed.

  By the way, in the above-described embodiment, as shown in FIGS. 10A and 10B, the upper mounting plate 12 and the small beam 5 of the viscoelastic damper 10a are fastened and fixed by the fastening bolt 40 so as not to be relatively movable in the horizontal direction. The lower attachment plate 15 of the viscoelastic damper 10a and the intermediate column upper end plate 9c of the intermediate column 9 are attached so as to be slidable in the horizontal direction by the clamp 50. However, the present invention is not limited to this, and may be reversed. In other words, the upper mounting plate 12 and the small beam 5 of the viscoelastic damper 10a are mounted to be slidable in the horizontal direction by the clamp 50, while the lower mounting plate 15 of the viscoelastic damper 10a and the stud upper end plate 9c are fastened. The bolt 40 may be fastened and fixed so as not to be relatively movable in the horizontal direction. Furthermore, the clamp 50 may be applied to both, and both may be attached to be slidable in the horizontal direction.

  12A and 12B are explanatory views of a modification of the attachment structure of the viscoelastic damper 10a. 12A is a side view, and FIG. 12B is a BB cross-sectional view in FIG. 12A.

  In the above-described embodiment, the viscoelastic damper 10a is configured to be slidable with respect to the stud 9 serving as a connecting member to the floor slab 25 in order to prevent the input of a horizontal force to the viscoelastic damper 10a during an earthquake. However, this modification of the mounting structure is different in that the viscoelastic damper 10a is configured to be slidable with respect to the small beams 5 of the lattice beam 2. Another difference is that the above-described clamp 50 is not used in the method of bringing the attachment surface 12d of the viscoelastic damper 10a into close contact with the attachment surface 5d of the small beam 5 of the lattice beam 2. Other configurations are generally the same as those in the above-described embodiment.

  The lower mounting plate 15 of the viscoelastic damper 10a is fastened and fixed to the stud 9 by fastening bolts 40. Specifically, a fastening bolt 40 is provided by vertically passing both the lower mounting plate 15 of the viscoelastic damper 10a and the intermediate column upper end plate 9c of the intermediate column 9 and fastening of a nut 41 that is screwed into the fastening bolt 40 Due to the force, the lower mounting plate 15 and the stud upper end plate 9c are fixed so as not to move relative to each other in the vertical direction and the horizontal direction in a close contact state in which the mounting surfaces 15d and 9d overlap each other.

  On the other hand, the upper attachment plate 12 of the viscoelastic damper 10 a is attached to the small beam 5 of the lattice beam 2. That is, the upper surface 12d of the upper mounting plate 12 is used as a mounting surface on the viscoelastic damper 10a side, and the lower surface 5d of the lower flange 5f of the small beam 5 is used as a mounting surface on the small beam 5 side. Are slidably attached while being superimposed on each other.

  The sandwiching member 60 for slidably contacting is any one of a bolt 61, a nut 62 screwed into the bolt 61, the lower flange 5f of the small beam 5 or the upper mounting plate 12 of the viscoelastic damper 10a. An elongated bolt hole 5h formed on one side, a round bolt hole 12h formed on the lower flange 5f of the small beam 5 or the remaining one of the upper mounting plate 12, and an axial force variation of the bolt 61. And a disc spring 63 for restraining.

  In this example, the long hole-shaped bolt hole 5 h is formed through the lower flange 5 f of the small beam 5, and the longitudinal direction of the long hole-shaped bolt hole 5 h is aligned with the longitudinal direction of the small beam 5. The length is set based on the assumed sliding amount between the mounting surfaces 12d and 5d at the time of the earthquake. On the other hand, the circular bolt hole 12 h is formed through the upper mounting plate 12, and the inner diameter thereof is set to a diameter having a minimum clearance necessary for passing the bolt 61.

  When the bolt 61 is passed through the bolt holes 5h and 12h with the nut 62, the disc spring 63 is interposed between the lower flange 5f and the bolt head portion 61a or the nut 62. A resilient force of 63 is applied to the lower flange 5f of the small beam 5 and the upper mounting plate 12 as a pinching force through the axial force of the bolt 61. For convenience of explanation, it is assumed below that the bolt head 61a is located on the small beam 5 side as shown in FIGS. 12A and 12B.

  Here, the static frictional force F generated between the mounting surface 5d of the small beam 5 and the mounting surface 12d of the upper mounting plate 12 of the viscoelastic damper 10a is expressed by the following equation 2 by adjusting the elastic force of the disc spring 63. Adjusted to satisfy.

Static friction force F <viscous load of viscoelastic damper-static friction force f of pinching member ... Formula 2
In addition, the definition of “assumed damage load” in the above formula 2 is the same as described above. In addition, the “static frictional force f of the sandwiching member” in the equation 2 is the horizontal static frictional force f3 between the sandwiching member 60 and the small beam 5 and between the sandwiching member 60 and the viscoelastic damper 10a. Is the smaller frictional force of the horizontal static frictional force f4. Specifically, in the example of FIGS. 12A and 12B, the former static frictional force f3 is the static frictional force between the disc spring 63 and the sliding member 66 or the upper surface 5u of the lower flange 5f of the sliding member 66 and the small beam 5. The static friction force f4 is a static friction force between the nut 62 and the lower surface 12f of the upper mounting plate 12 of the viscoelastic damper 10a.

  And if the static frictional force between the mounting surfaces 5d and 12d is set so as to satisfy the above formula 2, even if a large horizontal force acts on the double floor structure 1 during an earthquake, Before the force exceeding the damage assumed load is applied to the viscoelastic damper 10a, the horizontal sliding between the mounting surfaces 5d and 12d is started, whereby the viscoelastic damper 10a and the lattice beam 2 are moved. The edge of the beam 5 is cut off. As a result, the input of the horizontal force to the viscoelastic damper 10a is suppressed, and the breakage is effectively prevented. In order to reliably reduce the friction coefficient between the mounting surfaces 5d and 12d, a sliding material having a low friction coefficient such as a fluororesin such as PTFE described above is interposed between the mounting surfaces 5d and 12d. Good.

  A plurality of (four in this case) such sandwiching members 60 are arranged in the longitudinal direction of the small beam 5 to form a sandwiching member row, and the sandwiching member row is an H-shaped steel of the small beam 5. For example, two rows are provided across the web 5w, but the arrangement is not limited to this example.

  By the way, like the clamp 50 of the above-mentioned embodiment, the pinching member 60 is attached across both the viscoelastic damper 10a and the small beam 5 via the disc spring 63 and the nut 62. On the other hand, when the large horizontal force is applied, the viscoelastic damper 10a and the small beam 5 are cut off and relatively moved (slid) in the horizontal direction. Therefore, if both the disc spring 63 and the nut 62 of the sandwiching member 60 are firmly fixed to the small beam 5 and the viscoelastic damper 10a, respectively, the sandwiching member 60 during the relative movement described above. Receives a horizontal tensile force or the like from both the beam 5 and the viscoelastic damper 10a, which may cause the bolt 61 of the sandwiching member 60 to be tilted, etc. The bolt 61 may be damaged by receiving a large shearing force from the bolt hole 12h. As a result, every time an earthquake occurs, re-installation work such as replacement of bolts 61 is forced after the earthquake, which is inconvenient.

  Therefore, in order to make the pinching member 60 maintenance-free, the friction coefficient related to the horizontal static frictional force between the pinching member 60 and the small beam 5 is set to the horizontal coefficient between the pinching member 60 and the viscoelastic damper 10a. It is smaller than the coefficient of friction related to the static friction force in the direction. As a result, when the viscoelastic damper 10a and the small beam 5 are moved relative to each other, the sandwiching member 60 is surely attached to the viscoelastic damper 10a based on the above-described difference in the friction coefficient, and quickly with respect to the small beam 5. To slide. As a result, problems such as the inclination of the bolt 61 of the sandwiching member 60 and the breakage of the bolt as described above are effectively prevented.

  In addition, as a specific method of giving a difference to the above-described friction coefficient, for example, as shown in FIGS. 12A and 12B, the upper surface 5u of the disc flange 63 and the lower flange 5f of the small beam 5 ("the opposite side of the mounting surface Between the nut 62 and the lower surface 12f of the upper mounting plate 12 (corresponding to "the surface opposite to the mounting surface"). )), The above-mentioned sliding material 66 is not interposed.

  In addition, according to this clamping member 60, the drop off from the upper mounting plate 12 and the lower flange 5f that may have occurred in the case of the clamp 50 structure of the above-described embodiment can never occur, and is excellent in that respect. Further, the friction force between the mounting surfaces 5d and 12d is obtained by utilizing the constant elastic force region of the disc spring 63 (the range of the deflection amount in which the elastic force is maintained substantially constant with respect to the deflection amount variation). It is also excellent in that it can be set to be substantially constant.

=== Other Embodiments ===
As mentioned above, although embodiment of this invention was described, this invention is not limited to this embodiment, The deformation | transformation as shown below is possible in the range which does not deviate from the summary.

  In the above-described embodiment, the vertical large beam 4L and the horizontal large beam 4C are orthogonal to each other in the water surface, but the intersection angle between the vertical large beam 4L and the horizontal large beam 4C is not limited to 90 °. , They may intersect at an angle other than 90 °. That is, the opening shape of the lattice may be a parallelogram such as a rhombus. However, the longitudinal large beams 4L and 4L are arranged in parallel to each other so as to form a lattice shape, the horizontal large beams 4C and 4C are arranged in parallel to each other, and the longitudinal small beams 5L are parallel to the longitudinal large beams 4L. Needless to say, the transverse beam 5C is arranged in parallel with the transverse beam 4C.

  In the above-described embodiment, the H-shaped steel is exemplified as the main material of the large beam 4 and the small beam 5 related to the lattice beam 2. However, the present invention is not limited to this as long as the steel material can be assembled into a lattice. Or angle steel may be used.

  In the above-described embodiment, the intermediate column upper end plate 9c is exemplified as the attachment portion on the side of the intermediate column 9 to which the lower attachment plate 15 of the viscoelastic damper 10a is attached. However, any plate can be used as long as the plate can have a horizontal upper surface. For example, an appropriate steel material such as an H-shaped steel, a grooved steel, or an angle steel may be used.

  In the above-described embodiment, the H-beam is used for the small beam 5, but the plate portion extending in the horizontal direction corresponding to the flange 5f (5Cf, 5Lf) of the H-beam is provided at the upper or lower portion. It is not limited to this as long as it is a steel material, and, for example, channel steel or angle steel may be used.

1 Double floor structure, 2 lattice beams, 2m lattice beams,
4 girder, 4C lateral girder, 4L longitudinal girder,
5 Beam, 5C Horizontal beam, 5L Vertical beam,
5f flange (mounting part), 5Cf flange, 5Lf flange,
5w web, 5Cw web, 5Lw web 5d bottom surface (mounting surface), 5h bolt hole, 5j connecting plate,
5r rib plate, 5u upper surface (surface opposite to the mounting surface),
6 Floor panels, 8 pillars (support members), 8a braces, 8b studs,
9 stud (connecting member), 9c stud top plate (one mounting part),
9d upper surface (mounting surface), 9f lower surface (surface opposite to the mounting surface),
9w web, 10 damping means, 10a viscoelastic damper (damping member),
12 Upper mounting plate (mounting part), 12d Upper surface (mounting surface),
12f bottom surface (surface opposite to the mounting surface), 12h bolt hole,
13 Vertical plate, 14 Lower member,
15 lower mounting plate (mounting part), 15d mounting surface,
15f top surface (surface opposite to the mounting surface), 15h bolt hole,
16 Vertical plate, 17 Viscoelastic body, 19 Assembly bolt,
21 Upper floor, 25 floor slab, 25s upper surface,
40 fastening bolts, 41 nuts, 44 fastening bolts,
50 clamp, 50a end, 51 jack bolt,
53 sliding material, 55 pressure receiving plate, 60 sandwiching member,
61 bolt, 61a head, 62 nut,
66 sliding materials, 81 braces, 82 studs,
91 triangular truss structure (connecting member), 91a diagonal, 91b diagonal,
93 Spacer (connecting member), 93a diagonal, 93b diagonal,
CP intersection (intersection), S clearance, SP space

Claims (7)

It is a double floor structure installed at the top of the floor slab of the building frame,
A plurality of large beams supported horizontally via a support member above the floor slab, and a lattice beam having a plurality of small beams laid horizontally between the opposed large beams;
A damping member that damps the vertical vibration of the lattice beam,
One end of the damping member is connected to the small beam so that the damping member attenuates vibration in the vertical direction of the lattice beam through the small beam, and the other end of the damping member is The double floor structure is connected to a portion other than the lattice beam. The double floor structure according to claim 1,
The other end of the damping member is connected to the floor slab or the support member via a connecting member. The double floor structure according to claim 2,
The double floor structure, wherein the connecting member is a triangular truss structure or a ramen structure. The double floor structure according to any one of claims 1 to 3,
The double floor structure according to claim 1, wherein the one end portion of the damping member is connected to the beam at the intersection of the beam beams intersecting each other of the lattice beam. The double floor structure according to any one of claims 1 to 4,
The damping member has attachment portions at the one end and the other end, respectively.
The damping member is at least one attachment portion of the attachment portion of the small beam to which the attachment portion of the one end portion is attached or the attachment portion of the portion other than the lattice beam to which the attachment portion of the other end portion is attached. It is slidably attached to the mounting surface of the
A holding member for holding the one mounting portion and the mounting portion for the damping member in contact with each other on the surface opposite to the mounting surface and sandwiching the mounting portions;
The friction coefficient related to the horizontal friction force between the sandwiching member and the one attachment portion is different from the friction coefficient related to the horizontal friction force between the sandwiching member and the attachment portion of the damping member. A double floor structure characterized by The double floor structure according to claim 5,
The one attachment part is wider in the horizontal direction than the attachment part of the damping member,
The coefficient of friction related to the frictional force in the horizontal direction between the sandwiching member and the mounting part of the damping member is larger than the coefficient of friction related to the frictional force in the horizontal direction between the sandwiching member and the one mounting part. Double floor structure characterized by large The double floor structure according to claim 5 or 6,
The sandwiching member has a pair of sandwiching portions opposed to each other with a gap between them at both ends of the U-shaped or C-shaped member, and at least one of the pair of sandwiching portions serves as the other sandwiching portion. A double floor structure characterized by being a clamp that can be moved forward and backward.

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