JP3713645B2 - Seismic isolation device using laminated rubber - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a seismic isolation device suitable for reducing the input of seismic motion in, for example, various building structures.
[0002]
[Prior art]
In recent years, various seismic isolation devices have been developed to minimize shaking and damage caused by earthquakes in buildings and condominiums.
In this seismic isolation device, so-called laminated rubber having a structure in which viscoelastic bodies and steel plates are alternately laminated in the vertical direction is often used. Laminated rubber is interposed between the foundation of the building and the upper housing constructed on this foundation, for example, and when there is horizontal input due to an earthquake or the like, the viscoelastic body deforms in the horizontal direction. As a result, the vibration period of the upper housing is prolonged, and the vibration energy of the upper housing is absorbed by the damping device attached to the seismic isolation device to suppress the shaking.
[0003]
[Problems to be solved by the invention]
However, the conventional seismic isolation devices have the following problems. That is, for laminated rubber often used as a seismic isolation device, the viscoelastic body (rubber) constituting the rubber has a sufficiently high vertical compression strength but a low tensile strength. For this reason, if the tensile force in the vertical direction acts excessively on the laminated rubber, cracks and voids are generated in the viscoelastic body and the rigidity and strength are remarkably reduced, and the function as a seismic isolation device cannot be achieved.
As a structure in which a large tensile force acts in the vertical direction as described above, for example, a high-rise building or the like having a large height to width ratio (aspect ratio), an irregular shape such as an L shape or a trapezoidal shape in plan view. There are buildings that have a flat shape, those whose fluctuation axial force during an earthquake is greater than the long-term load, and those that have a large roof and generate buoyancy due to strong wind. It is impossible to apply a seismic isolation device employing conventional laminated rubber to such a structure.
[0004]
The present invention has been made in view of the above circumstances, and absorbs vibrations acting in the horizontal direction while allowing the upper casing to lift due to the tensile force even when a tensile force acts on the structure in the vertical direction. The purpose is to provide a seismic isolation device.
[0005]
[Means for Solving the Problems]
As a means for solving the above problems, a seismic isolation device for constructing an upper housing on a foundation via laminated rubber and absorbing vibrations acting on the structure in a horizontal direction while allowing the upper housing to lift is provided. It is adopted.
[0007]
Isolator This is the base plate in contact with a surface on the plate fixed to the lower portion of the upper skeleton provided with a hole penetrating in the thickness direction in the upper flange of the laminated rubber, through a bolt through the spring washer in the hole It has a structure fixed to the base plate.
In this seismic isolation device, for horizontal input, since the bolt is passed through the hole, horizontal vibration acting on the upper housing is absorbed by the laminated rubber as usual. In addition, for vertical input, the upper casing is allowed to move upward with respect to the laminated rubber by using a spring washer while connecting the laminated rubber and the upper casing with bolts, and excessive tensile force is applied. Does not act on laminated rubber.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the seismic isolation device of the present invention will be described with reference to FIGS. 1 and 2.
In the seismic isolation device shown in FIG. 1, an upper housing 3 is constructed on a foundation 1 of a building structure via a laminated rubber 2.
[0011]
A base side base plate 11 for fixing the laminated rubber 2 is fixed to the upper surface of the base 1. A plurality of stud bolts 12 are welded to the lower surface of the base-side base plate 11, and the base-side base plate 11 is firmly fixed to the base 1 in a state where they are embedded in the concrete forming the base 1. Further, the base side base plate 11 is provided with a plurality of holes 13 penetrating in the thickness direction so as to draw a circle on the base 1, and the bottom surface of the base side base plate 11 is provided with a female screw part on the inner side. Pipes 14 are connected to the holes 13 and welded, and these sheath pipes 14 are also embedded in the concrete forming the foundation 1.
[0012]
The laminated rubber 2 is formed by alternately laminating circular steel plates 24 and rubber sheets 25 as damping parts 23 between the lower flange 21 and the upper flange 22 as in the conventional case. Arranged on the side base plate 11 and placed on the foundation 1.
[0013]
A plurality of holes 26 corresponding to the holes 13 provided in the base-side base plate 11 are provided in the lower flange 21 so as to draw a circle, and bolts 27 are screwed onto the sheath tube 14 through the holes 26 so that the lower flange 21 is provided. Is fixed to the base-side base plate 11.
[0014]
An upper casing side base plate 31 for connecting the laminated rubber 2 and the upper casing 3 is fixed to the upper surface of the upper flange 22. The upper housing side base plate 31 is provided with a plurality of holes 32 penetrating in the thickness direction and provided with a female screw part on the inside so as to draw a circle.
[0015]
A plurality of holes 28 corresponding to the holes 32 provided in the upper housing side base plate 31 are provided in the upper flange 22 so as to draw a circle, and bolts 29 are screwed into the holes 32 through the holes 28, and the upper flange 22. The upper housing side base plate 31 is fixed to the upper part.
[0016]
A steel pipe (convex portion) 33 having a circular cross section is welded to the center of the upper surface of the upper housing side base plate 31 in a direction coinciding with the virtual axis of the laminated rubber 2, and is mounted on the upper housing side base plate 31. On the lower surface of the upper housing 3 to be placed, a recess 34 is formed which corresponds to the outer shape of the steel pipe 33 and fits with the steel pipe 33 so as to be accommodated inside.
[0017]
The steel pipe 33 and the recess 34 are fitted with a slight gap, between the peripheral surface of the steel pipe 33 and the recess 34, and between the lower surface of the upper casing 3 and the upper casing side base plate 31, An insulating sheet 35 for cutting the edge between the upper casing 3 and the upper casing side base plate 31 is provided over the entire surface.
[0018]
In addition, on the inner top surface of the recess 34, there is a foamed polyethylene plate material 36 which is disposed before the concrete is placed in order to form the recess 34 around the steel pipe 33. Further, although not shown, a damping mechanism for absorbing vibration energy is provided between the foundation 1 and the upper housing 3.
[0019]
About a building structure provided with the seismic isolation apparatus comprised as mentioned above, when horizontal force acts by an earthquake etc. as shown to Fig.2 (a), the steel pipe 33 and the recessed part 34 are fitting. Therefore, the laminated rubber 2 and the upper casing 3 are apparently integrated, the laminated rubber 2 makes the horizontal vibration period of the upper casing 3 longer, and the vibration energy acting on the upper casing 3 is absorbed by the damping mechanism. In this way, seismic isolation of building structures is achieved.
[0020]
In addition, as shown in FIG. 2B, when a force (moment) is applied to cause the building structure to fall down due to an earthquake or the like, a compressive force or a tensile force acts on the seismic isolation device in the vertical direction. At this time, since the seismic isolation device is given a sufficient strength against the compressive force, the soundness of the attenuation portion 23 of the laminated rubber 2 is maintained.
Further, with respect to the tensile force, the upper housing 3 is not restrained by the upper housing side base plate 31 because the steel pipe 33 and the recess 34 are merely fitted, so that the upper housing 3 is attached to the upper housing side base plate 31. On the other hand, the tensile force is not transmitted to the laminated rubber 2 because it is spaced upward.
[0021]
Thereby, the soundness of the attenuation part 23 is maintained, such as a crack and a void are not generated in the rubber sheet 25 constituting the attenuation part 23, and the rigidity and strength of the laminated rubber 2 are not lowered. The function as a seismic isolation device can be maintained regardless of the seismic force.
[0022]
As a result, locations and structures where conventional seismic isolation devices using laminated rubber could not be applied, such as high-rise buildings, have a large ratio of height to width (aspect ratio), as well as an L-shape or platform The above seismic isolation device is also applied to buildings with irregularly shaped flat shapes, such as buildings whose variable axial force during an earthquake is greater than the long-term load, and those that have a large roof and generate buoyancy due to strong wind It is possible to provide seismic isolation performance.
Moreover, it is also possible to control the rigidity of a single wall by using this seismic isolation device in the lower part of a seismic wall.
[0023]
If the laminated rubber 2 has no tensile rigidity as described above, the stress redistribution is performed so that the tensile axial force acting on the position of the laminated rubber 2 is transmitted to the other laminated rubber via the upper housing 3. The
[0024]
Next, a second embodiment of the seismic isolation device of the present invention will be described with reference to FIG. In addition, about the structure already demonstrated in the said 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.
In the seismic isolation device shown in FIG. 3, a rubber sheet 100 having a high cushioning property instead of the insulating sheet is provided between the peripheral surface of the steel pipe 33 and the recess 34 and between the lower surface of the upper housing 3 and the upper housing side base plate 31. Is installed over the entire surface.
[0025]
According to the building structure including the above-described seismic isolation device, when the upper housing 3 is separated upward from the upper housing side base plate 31 by receiving a tensile force, the shock is lowered when the upper housing 3 is lowered onto the upper housing side base plate 31 again. Thus, the upper housing 3 can be seated on the laminated rubber 2 with little impact, and the impact on the inside of the upper housing 3 due to the impact of the seating can be reduced and the durability of the laminated rubber 2 can be ensured.
[0026]
Next, a third embodiment of the seismic isolation device of the present invention will be described with reference to FIG. In addition, about the structure already demonstrated in said embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.
In the seismic isolation device shown in FIG. 4, the upper housing side base plate 200 is configured in the same manner as the base side base plate 11 and is firmly fixed to the upper housing 3 in an upside down manner.
[0027]
With respect to the upper casing side base plate 200, the laminated rubber 2 is screwed into a sheath pipe 14 provided in the upper casing side base plate 200 through a hole 28 provided in the upper flange 22. A spring washer 202 is passed through the bolt 201, and the upper housing 3 including the upper housing side base plate 200 can be separated upward from the laminated rubber 2 within a range in which the spring washer 202 is elastically deformed. ing.
[0028]
According to the building structure provided with the above-described seismic isolation device, the upper casing 3 is moved upward relative to the laminated rubber 2 by using the spring washer 202 while connecting the laminated rubber 2 and the upper casing 3 with the bolt 201. Therefore, it is possible to prevent an excessive tensile force from being generated in the laminated rubber 2 and to ensure the durability of the laminated rubber 2.
[0029]
Next, a fourth embodiment of the seismic isolation device of the present invention will be described with reference to FIG. In addition, about the structure already demonstrated in said embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.
In the seismic isolation device shown in FIG. 5, the upper housing 3 is not fixed to the upper housing side base plate 31 fixed to the laminated rubber 2, similarly to the seismic isolation device shown in the first embodiment. A columnar body (convex portion) 300 is welded to the center of the upper surface of the upper housing side base plate 31 so as to protrude upward in a direction coinciding with the virtual axis of the laminated rubber 2. Furthermore, a concave portion 301 is formed on the lower surface of the upper housing 3 so as to have a space between the cylindrical body 300 and to be fitted with the cylindrical body 300 so that the cylindrical body 300 is accommodated inside.
[0030]
A space between the fitted cylindrical body 300 and the recess 301 is filled with a viscoelastic body 302 such as rubber asphalt. Further, an insulating sheet 303 is provided between the lower surface of the upper housing 3 and the upper housing side base plate 31 so as to cut an edge between the upper housing 3 and the upper housing side base plate 31.
[0031]
According to the building structure including the above-described seismic isolation device, the vertical vibration (jump) of the upper casing 3 caused by the compressive force or the tensile force acting in the vertical direction is absorbed by the viscoelastic body 302 and the upper casing is absorbed. The impact of the seating 3 on the inside of the upper housing 3 can be reduced, and the durability of the laminated rubber 2 can be ensured.
[0032]
Further, when a horizontal force is applied, not only the damping mechanism but also the viscoelastic body 302 can absorb vibration energy acting on the upper housing 3 to obtain higher seismic isolation performance.
[0035]
【The invention's effect】
As described above, a hole that penetrates in the thickness direction is provided in the upper flange of the laminated rubber, and a base plate that is in contact with the plate is fixed to the lower portion of the upper housing, and a spring washer is passed through the hole provided in the base plate. According to the seismic isolation device having the structure in which the bolts are inserted and attached, the upper casing is allowed to move upward with respect to the laminated rubber, so that an excessive tensile force is prevented from being produced on the laminated rubber. The durability of rubber can be ensured.
[Brief description of the drawings]
FIG. 1 is an elevational sectional view showing a first embodiment of a seismic isolation device according to the present invention.
FIG. 2 is an elevational sectional view showing a state of the seismic isolation device when horizontal and vertical external forces are applied to the seismic isolation device shown in FIG. 1;
FIG. 3 is an elevational sectional view showing a second embodiment of the seismic isolation device according to the present invention.
FIG. 4 is an elevational sectional view showing a third embodiment of the seismic isolation device according to the present invention.
FIG. 5 is an elevational sectional view showing a fourth embodiment of the seismic isolation device according to the present invention.
[Explanation of symbols]
1 Foundation 2 Laminated Rubber 3 Upper Housing 33 Steel Pipe (Convex)
34 Recess 100 Rubber sheet (viscoelastic body)
201 Bolt (shaft member)
202 Spring washer 300 Cylinder (convex part)
301 Concavity 302 Viscoelastic body

Claims (1)

An upper case is constructed on a foundation via laminated rubber, and the seismic isolation device absorbs vibrations acting in the horizontal direction while allowing the upper case to float,
A hole that penetrates in the thickness direction is provided in the upper flange of the laminated rubber, and a base plate that is in contact with the plate is fixed to the lower part of the upper housing, and a bolt through a spring washer is fixed to the base plate through the hole. Seismic isolation device using laminated rubber.

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