JP2006022483A - Earthquake resistant structure of suspended ceiling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an earthquake resistant structure of a suspended ceiling, which enables the width of the swing of the ceiling during an earthquake to be effectively suppressed to be equal to/smaller than an allowance by providing a hysteresis damping member in an optimum position corresponding to an upper structure, without reference to a position of a suspension member, and which prevents bending moment in an out-of-plane direction from acting on the ceiling during the earthquake. <P>SOLUTION: Characteristically, the ceiling 1 is supported in the state of being suspended from the upper structure 3 via the suspension member 2; the hysteresis damping member 4 separate from the suspension member 2 is interposed between the upper structure 3 and the ceiling 1; an upper end 4a of the member 4 is rigidly joined to the upper structure 3; and a lower end 4b thereof is connected to the ceiling 1 so as to be vertically displaceable relatively to the ceiling 1 and to exert a hysteresis damping effect when the ceiling 1 is horizontally displaced during the earthquake. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a seismic structure for a suspended ceiling that is used as a ceiling in a clean room, an office, or the like and supported by being suspended from an upper structure via a suspension member.

  Conventionally, as a suspended ceiling used in a clean room or the like, for example, as shown in FIG. 8, a plurality of frames are assembled in a lattice shape, and a panel is fitted in the lattice to form a ceiling 20. A system ceiling having a pendulum type suspended structure in which an upper end portion 21a is suspended by a suspension member 21 made of a round bar or the like that is pin-joined to the upper structure 22 is known.

  According to this system ceiling, equipment such as a fan filter unit, a lighting fixture, a power supply line, or a control line can be attached to the frame of the ceiling 20 in advance, and these can be installed integrally. However, the ceiling 20 has a longer hanging length from the upper structure 22 than the general ceiling structure, and the ceiling 20 has various weights. Since the equipment is installed, it is necessary to take some seismic measures.

Therefore, in the system ceiling of the pendulum type suspension structure, the brace 23 is disposed between the suspension members 21 to enhance the earthquake resistance.
However, although the pendulum-type suspension structure can suppress the horizontal force acting on the suspension member 21 below a permissible value at the time of a small and medium earthquake, the brace 23 and the suspension member 21 are quickly moved at the time of a large earthquake. As a result, the ceiling 20 shook like a pendulum and collided with a wall surface or the like, and there was a possibility of causing great damage.

  For this reason, as shown in FIG. 9, by providing a suspension member 25 having increased rigidity and proof stress by using a pipe material or the like between the suspension members 21, the suspension member 25 can withstand a large earthquake. A hanging structure is known that prevents buckling of the other members 21 and 23. That is, according to this suspension structure, since the suspension member 25 having high rigidity is deformed in an elastic region even with a large seismic force, the suspension member 21 and the brace as in the above-described pendulum type suspension structure. It becomes possible to prevent the ceiling 20 from buckling and colliding with a wall surface or the like by the ceiling 20 swinging like a pendulum.

  However, in the suspended ceiling shown in FIG. 9, since the horizontal force acting on the ceiling 20 increases as the earthquake increases, the system ceiling itself cannot withstand a large earthquake, and the joint portion of the frame constituting the ceiling 20 does not endure. There was a risk of breakage or dropping of equipment or panels attached to the frame.

In order to solve the above problems, the present inventors have previously proposed a suspended structure for a suspended ceiling having an earthquake resistant structure as shown in Patent Document 1 below.
As shown in FIG. 10, this suspended ceiling seismic structure is a suspension member for suspending the ceiling 20 from the upper structure 22, and the upper end portion 27 a is rigidly attached to the housing 22 together with the suspension member 21 made of a round bar or the like. In addition to being joined, the lower end portion 27b is connected to the ceiling 20, and the hysteresis attenuating member 27 is used which exhibits a hysteresis attenuating effect when the ceiling 20 is displaced in the horizontal direction during an earthquake.

According to the earthquake-resistant structure of the suspended ceiling shown in FIG. 10, the hysteresis energy corresponding to the area in the hysteresis loop is absorbed by the hysteresis damping member 27 exhibiting the hysteresis damping effect during the earthquake. There is an advantage that the horizontal force acting on the ceiling 20 sometimes and the horizontal displacement of the ceiling 20 can be reduced.
JP 2003-306990 A

  However, in the conventional earthquake-proof structure of the suspended ceiling shown in FIG. 9 or FIG. 10, the suspension member 25 and the hysteresis damping member 27 with increased rigidity and proof strength are provided above the position where the suspension member is to be installed. There is not always a superstructure housing suitable for fixing. For this reason, there exists a problem that the position which installs these suspending members 25 and the history attenuation | damping member 27 will be restrict | limited.

  In addition, the suspension member 21 formed of a round bar or the like does not restrain the vertical displacement of the ceiling 20, whereas the suspension member 25 and the hysteresis damping member 27 restrain the displacement in the vertical direction. In addition, the movement in the out-of-plane direction is locally different from the ceiling 20 at the time of the earthquake, and as a result, there is a possibility that the panel constituting the ceiling 20 is dropped. In addition, since a bending moment in the out-of-plane direction acts on the frame constituting the ceiling 20, it is necessary to separately provide bending reinforcement in order to prevent damage to the frame.

  The present invention has been made in view of such circumstances, and it is possible to provide a hysteresis damping member at an optimum position corresponding to the upper structure regardless of the position of the suspension member. An object of the present invention is to provide a suspended ceiling earthquake-resistant structure in which the width can be suppressed to an allowable value or less and a bending moment in an out-of-plane direction does not act on the ceiling during an earthquake.

  In order to solve the above-mentioned problem, the invention according to claim 1 suspends and supports the ceiling from the upper structure via the suspension member, and the suspension member is interposed between the upper structure and the ceiling. Comprises a separate hysteresis damping member, and the hysteresis damping member has an upper end rigidly joined to the upper structure and a lower end relative to the ceiling relative to the ceiling in the vertical direction. It is displaceable and is connected so as to exhibit a hysteresis attenuation effect when the ceiling is displaced in the horizontal direction during an earthquake.

  Here, “to rigidly join the suspension member to the superstructure” means that the two members are joined with sufficient rigidity to cause the suspension member to undergo elastic-plastic deformation when an assumed seismic force (horizontal force) acts on the ceiling. It means joining. As the joining structure, for example, a base plate is provided at the upper end portion of the suspension member, the base plate is fastened to the upper structure with an anchor bolt, and a rib plate is attached to the corner of the base plate and the suspension member. The structure in which the upper end of the lowering member is rigidly joined to the upper structure, or the upper end of the hanging member is joined to the upper structure, and the diagonal member is installed from the middle part of the hanging member toward the upper structure. A structure in which the lowering member is rigidly joined to the upper structure as a whole is preferable.

  In addition, “the lower end portion of the hysteresis damping member can be relatively displaced in the vertical direction relative to the ceiling, and is connected so as to exert a hysteresis damping effect when the ceiling is displaced in the horizontal direction during an earthquake” When an assumed seismic force (horizontal force) acts on the ceiling, the horizontal force is transmitted to the lower end of the hysteresis damping member, causing the hysteresis damping member to elastically plastically deform, and the ceiling can move freely in the vertical direction. Are connected so as not to restrain them.

  As such a connection structure, for example, as in the invention described in claim 2, the lower end portion of the hysteresis damping member is formed by a tubular member, and the outer method is smaller than the inner method of the tubular member on the ceiling side. The connecting member or the connecting member whose inner method is larger than the outer method of the tubular member is fixed, the connecting member is inserted into the lower end portion of the tubular member, or the lower end portion of the tubular member is inserted into the connecting member. Structure is mentioned.

  In this case, the invention described in claim 3 is characterized in that an impact buffering member is interposed between the lower end portion of the hysteresis damping member and the connecting member.

  According to the invention according to any one of claims 1 to 3, since the hysteresis damping member separate from the suspension member is interposed between the upper structure and the ceiling, the suspension member should be provided. Regardless of the position, the hysteresis attenuating member can be provided at the optimum position corresponding to the superstructure, which is easy to attach, thereby increasing the degree of freedom in design. Since the hysteresis damping member exerts a hysteresis damping effect during an earthquake, the earthquake energy corresponding to the area in the hysteresis loop is absorbed, so that the horizontal force acting on the ceiling and the horizontal direction of the ceiling during the earthquake are absorbed. Each displacement can be reduced.

  In addition, since the history attenuating member is provided so as to be relatively displaceable in the vertical direction with respect to the ceiling, the hysteresis attenuating member is moved up and down of the ceiling even if the suspension member allows the ceiling to move up and down during an earthquake. Therefore, the local bending stress acts on the ceiling and the panel does not drop.

  Further, according to the second aspect of the invention, the structure is simple, the vertical displacement relative to the ceiling is enabled, and the seismic force (horizontal force) acting on the ceiling in all horizontal directions. Force) can be reliably transmitted to the hysteresis damping member, and the hysteresis damping effect can be exhibited.

  According to a third aspect of the present invention, there is a backlash between the lower end portion of the hysteresis damping member and the connecting member by the shock absorbing member interposed between the lower end portion of the hysteresis damping member and the connecting member. Can be eliminated. Here, as the buffer member, for example, rubber is suitable, and the hardness of the rubber is set so that the inclination of both of them falls within 1/10 or less when the hysteresis damping member undergoes elasto-plastic deformation during an earthquake. Is preferred.

(First embodiment)
FIGS. 1-4 shows 1st Embodiment of the earthquake-resistant structure of the suspended ceiling based on this invention, and the code | symbol 1 in a figure is a ceiling.
The ceiling 1 is constructed by assembling a plurality of frames in a lattice shape, and a panel is fitted in the lattice. The ceiling 1 is a suspension made of a round bar or the like in which upper and lower ends 2a and 2b are pin-joined. The member 2 is suspended and supported from, for example, the beam 3 of the upper structure.

In the suspended ceiling seismic structure, a hysteresis damping member 4 separate from the suspension member 2 is interposed at a predetermined location between the beam 3 and the ceiling 1.
The hysteresis attenuating member 4 has an upper end 4a rigidly joined to the beam 3 and a lower end 4b that can be displaced relative to the ceiling 1 in the vertical direction, and the ceiling is displaced horizontally during an earthquake. Are connected so as to exert a hysteresis damping effect.

  That is, the hysteresis damping member 4 is formed of a square steel pipe (tough member) that exhibits a hysteresis damping effect by elasto-plastic deformation when the ceiling 1 connected to the lower end 4b is greatly displaced in the horizontal direction during an earthquake. A rectangular base plate 5 is integrally provided on the upper end 4a. Here, a plurality of rib plates 6 are attached to the corners of the base plate 5 and the hysteresis damping member 4 in the orthogonal direction. The rib plates 6 are arranged to face each other so as to sandwich the hysteresis attenuating member 4 from two directions orthogonal to each other in a horizontal plane.

The base plate 5 is fastened to the flange of the beam 3 by a high-strength bolt 7 or an intermediate bolt, whereby the upper end portion 4 a of the hysteresis damping member 4 is rigidly joined to the beam 3.
On the other hand, a connecting member 8 is fixed to the ceiling 1 located at the lower end 4b of the hysteresis attenuating member 4.

  As shown in FIG. 4, the connecting member 8 includes a rectangular base plate 8a fixed to the ceiling 1 by a large number of bolts 8c, and a connecting pipe 8b made of a square steel pipe integrally joined to the base plate 8a. The dimension of each side in the outer periphery of the connecting pipe 8b is set to be shorter than the dimension of each side in the inner periphery of the hysteresis attenuating member 4. The connecting pipe 8b of the connecting member 8 is loosely inserted into the lower end 4b of the hysteresis attenuating member 4.

  A rubber (buffer member) 9 having a predetermined hardness is interposed between the outer periphery of the connecting pipe 8 b and the inner wall of the hysteresis damping member 4. Here, the rubber 9 is set to such a hardness that the inclination of both of them falls within 1/10 or less when the hysteresis damping member undergoes elasto-plastic deformation during an earthquake.

(Second Embodiment)
5-7 shows 2nd Embodiment of the earthquake-proof structure of the suspended ceiling based on this invention, About the same component as what was shown in FIGS. 1-4, the same code | symbol is attached | subjected. The description is simplified.
In this suspended ceiling earthquake-resistant structure, a hysteresis damping member 11 separate from the suspension member 2 is interposed at a predetermined location between the beam 3 and the ceiling 1. The hysteresis attenuating member 11 is made of a round steel pipe (tough member) that exhibits a hysteresis attenuating effect when the ceiling 1 is greatly displaced in the horizontal direction during an earthquake, and has a rectangular shape at the upper end 11a. A base plate 12 is provided integrally.

  The base plate 12 is fastened to the flange of the beam 3 by a high-strength bolt 13 or a medium bolt, and a plurality of diagonal members 14 are installed from the upper part of the hysteresis damping member 11 toward the beam 3 to The damping member 11 is rigidly joined to the beam 3 as a whole.

  That is, on the upper part of the hysteresis damping member 11, the mounting plate 15 of each diagonal member 14 is attached so as to extend from the outer peripheral surface of the hysteresis damping member 11 in the beam-to-beam direction and the crossing direction. Bolt holes are drilled in the respective mounting plates 15, and the intermediate bolts 16 are inserted from the bolt holes through the bolt holes drilled at the lower end of the diagonal member 15, and tightened with nuts. The lower end of 14 is connected to the mounting plate 15.

On the other hand, a bracket 17 is fixed along the lower surface of the beam 3, and the upper end portion of the diagonal member 14 is connected to the bracket 17 by an intermediate bolt 16.
A connecting member 18 is fixed to the ceiling 1 located at the lower end 11b of the hysteresis attenuating member 11.

  As shown in FIG. 7, the connecting member 18 includes a rectangular base plate 18a fixed to the ceiling 1 by a number of bolts 18c, and a connecting pipe 18b made of a round steel pipe integrally joined to the base plate 18a. The outer diameter of the connecting pipe 18b is set smaller than the inner diameter of the hysteresis damping member 11. Then, the connecting pipe 18 b of the connecting member 18 is loosely inserted into the lower end portion 11 of the hysteresis attenuating member 11.

  Furthermore, also in this embodiment, when the hysteresis damping member 11 is elasto-plastically deformed between the outer periphery of the coupling tube 18b and the inner wall of the hysteresis damping member 11, the inclination with respect to the coupling tube 18b is 1/10 or less. A rubber (buffer member) 19 set to have a hardness that fits in is interposed.

  According to the suspension ceiling damping structure shown in the first and second embodiments described above, between the beam 3 of the upper structure and the ceiling 1, the hysteresis damping member 4, which is separate from the suspension member 2, 11 is provided, the hysteresis damping members 4 and 11 can be provided at optimum positions corresponding to the upper structure regardless of the position where the suspension member 2 is to be provided, and the degree of freedom in design can be increased. Increase. Further, the hysteresis damping members 4 and 11 exhibit a hysteresis damping effect during an earthquake, whereby the horizontal force acting on the ceiling 1 and the horizontal displacement of the ceiling during the earthquake can be reduced.

Moreover, since the hysteresis damping members 4 and 11 are provided so as to be relatively displaceable in the vertical direction with respect to the ceiling 1 via the connecting members 8 and 18, the suspension member 2 allows the ceiling 1 to move up and down during an earthquake. In this case, the hysteresis damping members 4 and 11 move up and down relatively with respect to the connecting members 8 and 18 so that the vertical movement of the ceiling 1 can be followed. As a result, local bending stress acts on the ceiling 1 so that the panel does not drop and the like does not occur.
Further, since the rubbers 9 and 19 are interposed in the gaps between the lower end portions 4b and 11b of the hysteresis attenuating members 4 and 11 and the connecting members 8 and 18, the play between them can be eliminated.

  In the first and second embodiments, the case where a square steel pipe or a round steel pipe is used as the hysteresis attenuating members 4 and 11 is described. As long as 1 is a member that exhibits a hysteresis damping effect when displaced in the horizontal direction, it may be a steel pipe having another cross-sectional shape, an H-shaped steel, an I-shaped steel, a cast steel, or the like.

  Further, the upper structure that rigidly joins the upper end portions 4a and 11a of the hysteresis damping members 4 and 11 is not limited to the above-described beam 3, but the hysteresis damping members 4 and 11 are rigidly joined to obtain a sufficient hysteresis damping effect. Reinforced concrete beams, floor slabs, etc. may be used as long as they can exhibit the above.

  Furthermore, in the above-described embodiment, each of the hysteresis damping members 4 and 11 is provided at the lower ends 4b and 11b of the hysteresis damping members 4b and 18b so as to be relatively movable up and down. The lower ends 4b and 11b of the damping members 4 and 11 may be inserted into the connecting pipes 8b and 18b. Also, the hysteresis attenuating members 4 and 11 need not be formed of a single material over the entire length thereof, and the main body portion and the lower end portion can be formed of different materials.

It is a front view which shows 1st Embodiment of the earthquake-resistant structure of the suspended ceiling which concerns on this invention. It is a front view which shows the log | history attenuation member of FIG. It is the III-III sectional view taken on the line of FIG. The connection member of FIG. 2 is shown, (a) is a front view, (b) is a top view. It is a front view which shows the log | history attenuation member in the 2nd Embodiment of this invention. FIG. 6 is a sectional view taken along line VI-VI in FIG. 5. It shows the connecting member of FIG. 5, (a) is a front view, (b) is a plan view. It is a front view which shows the earthquake-resistant structure of the conventional suspension ceiling. It is a front view which shows the seismic structure of the other conventional suspended ceiling. It is a front view which shows the earthquake-resistant structure of the suspended ceiling which the present inventors proposed previously.

Explanation of symbols

1 Ceiling 2 Hanging member 3 Beam (superstructure)
4, 11 Hysteresis damping member 4a, 11a Upper end 4b, 11b Lower end 8, 18 Connecting member 8a, 18a Base plate 8b, 18b Connecting tube 9, 19 Rubber (buffer member)

Claims (3)

While supporting the ceiling from the upper structure via a suspension member, between the upper structure and the ceiling, a hysteresis damping member separate from the suspension member is interposed,
The hysteresis attenuating member has an upper end rigidly joined to the upper structure, a lower end can be displaced relative to the ceiling in the vertical direction, and the ceiling is horizontal when an earthquake occurs. A seismic structure for suspended ceiling, which is connected so as to exert a hysteresis damping effect when displaced to the   In the hysteresis damping member, the lower end portion is formed of a tubular member, and on the ceiling side, a connecting member whose outer method is smaller than the inner method of the tubular member, or an inner method is smaller than the outer method of the tubular member. The suspended ceiling according to claim 1, wherein a large connecting member is fixed and the connecting member is inserted into a lower end portion of the tubular member, or a lower end portion of the tubular member is inserted into the connecting member. Earthquake-resistant structure.   The earthquake-resistant structure of the suspended ceiling according to claim 2, wherein an impact buffering member is interposed between a lower end portion of the hysteresis damping member and the connecting member.

Images