JPH0434247A - Base isolation element - Google Patents

Abstract

PURPOSE:To make efficient earthquake isolation obtainable relating to an earthquake motion in a vertical direction by supporting a structure by supporting plates, laminated in a plurality of sheets, having elasticity in only the vertical direction and rigidity equal in an arbitrary direction in a horizontal surface. CONSTITUTION:In a base isolation element 1, its central part is fixedly tightened by a plurality of fixing metal fixtures 3 of bolts or the like by concentrically laminating a plurality of metal-made supporting plates 2 of different diameter formed in a disk shape. The supporting plate 2, having elasticity only in a vertical direction and rigidity equal in both orthogonal directions, is laminated so as to increase a diameter from a lower end side toward an upper end side. The supporting plate 2 is placed in a condition that the peripheral part is warped upward in the initial condition. A structure 5 is supported by arranging this base isolation element 1 between a foundation 4 and the structure 5, and the peripheral part of an upper end supporting plate 2b is fixed to the structure 5 by bolts 8 by fixing a lower end supporting plate 2a to a supporting bed 6, fixed by bolts 7 onto the foundation 4, by fixing metal fixtures 3 for fixedly tightening the supporting plate 2. Under this condition, the supporting plate 2 is placed in a horizontal condition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a seismic isolation device that supports and isolates a structure.

(Prior Art) Various types of seismic isolation devices have been proposed in the past in order to prevent structures from being destroyed by seismic motion caused by earthquakes.

FIG. 13 is an explanatory diagram showing a conventional general seismic isolation device. As shown in this figure, the seismic isolation device 1°O
A plurality of seismic isolation bags W100 are interposed between the lower part of the base 101 and the foundation 103 set on the ground 102, and the seismic isolation bags W100 support the structure and also exert a seismic isolation function during an earthquake, so that the structure 100 prevent it from being destroyed.

Next, various structures of the conventional seismic isolation device 100 described above will be explained in the first section.
This will be explained with reference to FIGS. 4 to 19.

The seismic isolation device 100 shown in FIGS. 14 and 15 is configured to exhibit a seismic isolation function only in the horizontal direction. That is, the seismic isolation device 100 shown in FIG.
01 with a support 105 interposed between the structure 10 and the lower part of the structure 10.
It has a structure that supports 1. The support 105 includes an elastic material 106 made of anti-vibration rubber or laminated rubber, which is flexible in the horizontal direction and highly rigid in the vertical direction, and an upper part of the elastic material 106. It is composed of an upper end plate 107 and a lower end plate 108 fixed to the lower part.The upper end plate 107 is attached to the lower part of the structure 101, and the lower end plate 1
08 are fixed to the upper part of the support stand 104, respectively.

When an earthquake occurs, the support body 105 is formed of an elastic material 106 due to the earthquake motion (horizontal earthquake motion).
By deforming in the horizontal direction, seismic energy is converted into deformation energy of the elastic material 106, and the seismic force transmitted to the structure 101 is reduced.

On the other hand, the seismic isolation device 10o shown in FIG.
A sliding plate 109 is fixed to the bottom of the foundation 10.
A support stand 104 is fixed to the upper part of the structure 101, and the support body 105 is interposed between the sliding plate 109 and the support stand 104 to support the structure 101. The upper end 107 of the support body 105 is slidably installed at the bottom of the sliding plate 109, and when an earthquake motion of a magnitude larger than a certain window (larger than the frictional force) acts on the sliding plate 109, the upper end 107 is slidably installed. Plate 109 and upper end plate 107 move relative to each other.

When an earthquake occurs, the support body 105 formed of the elastic material 106 is deformed in the horizontal direction by the seismic motion (horizontal seismic motion), and the seismic energy is converted into deformation energy of the elastic material 106. , the seismic motion transmitted to the structure 101 is reduced. Furthermore, if a larger seismic motion occurs than in the case described above, the support body 1.5 will be displaced in the horizontal direction, and the sliding plate 109 will be displaced in the horizontal direction.
The sliding plate 109 and the upper end plate 107 (i.e., the structure 101 and the support 104) move relative to each other against the frictional force between the upper end plate 107 of the supporting member 105, and the vibration caused by the frictional force The energy consumption reduces the seismic force transmitted to the structure 101.

By the way, the seismic isolation bag [1] shown in FIGS. 14 and 15 above
In 00, as described above, the elastic material 106 of the support body 105 has elasticity only in the horizontal direction and high rigidity in the vertical direction, so it exhibits a good seismic isolation function against earthquake motion in the horizontal direction. It does not exhibit a seismic isolation function against vertical seismic motion.

Therefore, when a relatively large vertical earthquake occurs, such as a direct earthquake, the structure 101 is supported by the foundation 103 via the support 1.5, so the vertical shaking is amplified and the structure There is a possibility that it will be transmitted to 101.

For this reason, three-dimensional seismic isolation devices have been proposed that provide seismic isolation in the horizontal and vertical directions. FIGS. 16 to 19 are schematic diagrams showing a conventional seismic isolation device 100 that performs three-dimensional seismic isolation.

The seismic isolation device fl 00 shown in FIG. 16 is a metal structure that is installed between the foundation 1゜3 and the structure 101, and has both ends that are elastic in the horizontal and vertical directions fixed to the foundation 103 and the structure 101, respectively. The structure is such that the structure 101 is supported by interposing a coil spring 110.

When an earthquake occurs, the coil spring 110 is elastically deformed in the horizontal and vertical directions due to the seismic motion (seismic motion in the horizontal and vertical directions), thereby absorbing and isolating the seismic motion in the horizontal and vertical directions. Demonstrates earthquake function.

The seismic isolation device 100 shown in FIG.
The structure 1 is constructed by interposing an air spring 113 configured by sealing air or other gas in a rubber membrane 112 fixed to the structure 1.
01, the elastic deformation of the rubber membrane 112 and the elasticity of the internal gas when compressed absorb horizontal and vertical seismic motions and exert a seismic isolation function.

The seismic isolation device 100 shown in FIG. 18 includes a support 105 formed of the above-described elastic material 106 and an air spring 113 connected to the upper part thereof, interposed between a foundation 103 and a structure 101. Horizontal seismic isolation is provided by support 105 and air spring 11
3, and air spring 1 is used for horizontal and vertical seismic isolation.
The structure is such that it can be done by looking at 13.

The seismic isolation device 100 shown in FIG. 19 includes a cart 116 provided with a plurality of ball bearings 115 that rotatably moves on a rolling plate 114 fixed on a foundation 103, and a guide shaft 117 connected to the upper part of the cart 116. It is composed of a metal coil spring 110 disposed inside,
This seismic isolation device 100 is interposed between a foundation 103 and a structure 101 to support the structure 101.

Furthermore, fixtures 118a are provided on both sides of the trolley 116.

Spring 119a, 119b whose one end side is fixed is connected to 118b, and the horizontal movement of truck 116 is restricted by the spring force of these springs 119a, 119b.

Both ends of the coil spring 110 and the guide shaft 117 are fixed to the upper part of the truck 116 and the lower part of the structure 101, respectively.

In this seismic isolation device 100, the horizontal seismic isolation is achieved by the rotation of the ball bearing 115 on the rolling plate 114, and the trolley 116 is moved by the spring 119a.

119b by moving against the spring force,
The structure is such that seismic isolation in the vertical direction is achieved by elastic displacement of a coil spring 110.

By the way, each of the seismic isolation devices 100 shown in FIGS. 16 to 19 described above has the following problems.

In the seismic isolation device 100 shown in FIG. 16, since the weight of the structure 101 is supported only by the elasticity of the coil spring 110, a large compressive deformation occurs in the coil spring 110 in the initial state. Therefore, when looking at the material strength of the coil spring 110, the amount of variable displacement from the initial compressed state to absorb shaking due to an earthquake is small. Therefore, it is difficult for the coil spring 110 to sufficiently support a large load, so the level of vertical seismic motion to be isolated has to be set to a relatively small level, and it cannot exhibit sufficient seismic isolation function in the event of a large earthquake. There wasn't.

In addition, the coil spring 110 deforms in the horizontal direction in response to horizontal seismic motion, but at the same time deforms in the vertical direction due to constraints on the geometric shape of the coil spring 110. The resulting vibration is a combination of a complex horizontal rotational direction and vertical direction.

Furthermore, since the coil spring 110 has low rigidity against rotation, when the structure 101 shakes horizontally and vertically due to an earthquake, a moment from the structure 101 acts on the coil spring 110 due to the inertia of the structure 101, causing the upper part to move. rotational displacement occurs. Therefore, as shown in FIG. 20, the coil spring 110 may be twisted at an angle θ, and the structure 10'l may undergo rocking vibration and be damaged.

In addition, in the seismic isolation device 100 shown in FIG. 17, the air spring 113 is not allowed to undergo large deformations in the horizontal and vertical directions due to constraints on the shape deformation of the rubber membrane 112. The seismic isolation function could not be demonstrated. Furthermore, since the air spring 113 has low rigidity against rotation, there is a risk that it may be twisted due to horizontal and vertical seismic motions, or rocking vibration may occur in the structure 101, causing damage.

In addition, in the seismic isolation device 100 shown in FIG. 18, when the horizontal relative displacement between the foundation 103 and the structure 101 becomes large due to seismic motion during a large earthquake, the support body 105 formed of the elastic material 106 deforms. Air spring with small capacity 1
13 may exceed the breaking displacement first. For this reason, this seismic isolation bag! 100 depends on the seismic isolation ability of the air spring 113, so it could not exhibit a sufficient seismic isolation function during a major earthquake. Furthermore, since the air spring 113 has low rigidity against rotation as described above, it may be twisted at an angle θ due to horizontal and vertical seismic motion (see FIG. 21), and rocking vibration may occur in the structure 101. There is a risk of damage.

Furthermore, in the seismic isolation device 100 shown in FIG. 19, seismic isolation is performed by a coil spring 110 having a guide shaft 117 disposed therein against earthquake motion in the vertical direction, but the rigidity of the guide shaft 117 is not high, the coil spring 110 cannot suppress rocking vibrations of the structure 101 caused by horizontal and vertical earthquake motions. Further, the coil spring 110 is
As mentioned above, the rigidity against rotation is small, so when the structure 101 shakes due to an earthquake, the moment from the structure 101 acts on the coil spring 110 due to the inertial force of the structure 101, causing rotational displacement in the upper part and twisting. It was not possible to demonstrate a good seismic isolation function in the event of a major earthquake.

(Problems to be Solved by the Invention) As described above, in the conventional seismic isolation device 100, some have a seismic isolation effect only in the horizontal direction, and others have mutual deformation in the horizontal and vertical directions due to earthquake motion in the horizontal and vertical directions. Because of the coupling, there is a problem in that complex vibrations occur in the structure 101.

Further, since the coil spring 110 and the air spring 113, which provide vertical seismic isolation, have low rigidity against rotation, there are problems in that they may twist or cause rocking vibrations in the structure 101.

Furthermore, the coil springs 110 and the air springs 113 were unable to perform effective seismic isolation because there was a difference in the applicable range of seismic isolation.

The present invention was made for the purpose of solving the above-mentioned problems, and is a seismic isolation device capable of suppressing torsional deformation and rocking vibration of a structure, and independently and efficiently performing seismic isolation in the horizontal direction and vertical direction. This is what we are trying to provide.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the first invention provides a structure in which the lower part is fixed to the upper part of the foundation between the structure and the foundation on the ground. The structure is characterized in that a plurality of support plates are laminated and interposed, the upper part of which is fixed to the lower part of the structure, elastic only in the vertical direction, and having substantially equal rigidity in any direction in the horizontal plane.

Further, the second aspect of the present invention provides a first support means having elasticity only in the horizontal direction, the lower part of which is disposed on the foundation, and the lower part of which is disposed between the structure and the foundation on the ground; and the upper part is fixed to the lower part of the structure,
It is characterized by interposing a second support means formed by laminating a plurality of support plates having elasticity only in the vertical direction and substantially equal rigidity in any direction in the horizontal plane.

(Function) According to the first aspect of the present invention, by supporting a structure by laminating a plurality of supporting plates having elasticity only in the vertical direction and having substantially equal rigidity in any direction in a horizontal plane, Good directional seismic isolation can be achieved. Furthermore, the structure of the present invention can maintain high rigidity against out-of-plane bending deformation of the support plate (corresponding to structural rocking deformation), and therefore can effectively suppress structural rocking. .

Further, according to the second invention, the structure is seismically isolated in the horizontal direction by the support means having elasticity only in the horizontal direction,
In addition, by performing seismic isolation in the vertical direction using multiple laminated support plates that have elasticity only in the vertical direction and approximately equal rigidity in any direction in the horizontal plane, the horizontal and vertical directions can be isolated independently. This can be done efficiently. Furthermore, with respect to horizontal and vertical shaking of the structure, complex vibrations including rocking vibration can be suppressed to a minimum.

(Example) Hereinafter, the present invention will be explained in detail based on the illustrated example.

FIGS. 1(a) and 1(b) are a side view and a plan view, respectively, showing a seismic isolation device according to a first embodiment of the present invention. As shown in both figures, this seismic isolation device 1 consists of a plurality of disk-shaped metal support plates 2 (four in the figure) with different diameters, stacked concentrically, Tightening is fixed by fixing metal fittings 3 such as bolts. The support plate 2 has elasticity only in the vertical direction (thickness direction) and equal rigidity in both orthogonal directions, and is laminated so that the diameter increases from the lower end side to the upper end side. Further, in the initial state, the outer peripheral portion of the support plate 2 is in an upwardly warped state.

Then, as shown in Figure 2, this seismic isolation device 1 is installed on the foundation 4.
and the structure 5 to support the structure 5, and the lower end support plate 2a is fixed to the support base 6 which is fixed to the foundation 4 with bolts 7. It is fixed with the metal fittings 3, and the outer peripheral part of the upper end support plate 2b is attached to the structure 5 with bolts 8.
Fix it with.

In this state, the support plate 2 is in a horizontal state. In addition, a notch is provided at the lower part of the structure 5 facing the inner peripheral side of the upper end support plate 2b fixed with the bolt 8 to prevent interference between the upper end support plate 2b and the structure 5 due to vertical earthquake motion. A portion 5a is formed. With such a configuration, seismic isolation in the vertical direction can be performed.

The seismic isolation device 1 according to this embodiment is configured as described above, and as shown in FIGS. 3 and 4, when a geographical event occurs, the support plate 2 is moved by the earthquake motion (vertical earthquake motion). By vibrating in the vertical direction, seismic energy is converted into vibration energy of the support plate 2, and the seismic force transmitted to the structure 5 is reduced.

FIGS. 5(a) and 5(b) are a side view and a plan view, respectively, showing a seismic isolation device according to a second embodiment of the present invention.

As shown in both figures, this seismic isolation device 10 includes a plurality of metal support plates 2 (four in the figure) formed in the shape of a disk and having different diameters, which perform vertical seismic isolation. It is composed of a laminated rubber 11 that is placed under the rubber layer and performs seismic isolation in the horizontal direction.

The support plate 2 has elasticity only in the vertical direction (thickness direction) and equal rigidity in both orthogonal directions, and is laminated so that the diameter increases from the lower end side to the upper end side. Tightening is fixed by a plurality of fixing metal fittings 3 such as bolts. Further, in the initial state, the outer peripheral portion of the support plate 2 is in an upwardly warped state.

The laminated rubber 11 has elasticity only in the horizontal direction, and an upper end plate 12 and a lower end plate 13 are fixed to both end faces, respectively.
The support plate 2 and the upper end plate 12 are integrally connected by a fixture 3 that tightens and fixes the support plate 2.

As shown in FIG. 6, this seismic isolation device 10 is disposed between the foundation 4 and the structure 5 to support the structure 5, and a lower end plate 13 fixed to the lower end surface of the laminated rubber 11 is attached. It is fixed on the foundation 4 with bolts 7, and the outer peripheral part of the upper end support plate 2b is fixed on the structure 5 with bolts 8. In this state, the support plate 2 is in a horizontal state.

In addition, a notch is provided at the lower part of the structure 5 facing the inner peripheral side of the upper end support plate 2b fixed with the bolt 8 to prevent interference between the upper end support plate 2b and the structure 5 due to vertical earthquake motion. A portion 5a is formed. With such a configuration, three-dimensional seismic isolation in the horizontal and vertical directions can be performed.

The seismic isolation device 10 according to this embodiment is configured as described above, and when an earthquake occurs that has seismic motion only in the vertical direction, the support plate 2 is moved as shown in FIGS. 7 and 8. By vibrating in the vertical direction, seismic energy is transferred to the support plate 2.
The seismic force that is converted into vibration energy and transmitted to the structure 5 is reduced.

In addition, when an earthquake occurs that has seismic motion only in the horizontal direction, the laminated rubber 11 is elastically deformed in the horizontal direction, as shown in FIG. , the seismic force transmitted to the structure 5 is reduced.

At this time, the disk-shaped support plate 2 has high rigidity against torsional deformation, so no rocking vibration occurs in the structure 5, and also has high horizontal rigidity, so the support plate 2 deforms in the horizontal direction. Not at all.

Furthermore, in the event of an earthquake with vertical and horizontal seismic motion, as shown in FIG. elastically deforms in the direction.

Therefore, seismic energy is converted into vibration energy of the support body 2 and also into deformation energy of the laminated rubber 11, and the seismic force transmitted to the structure 5 is reduced.

At this time, since the support plate 2 has high rigidity against torsional deformation, no rocking vibration occurs in the structure 5.

In this way, in the case of earthquake motion only in the vertical direction, the support 2
In addition, in the case of seismic motion only in the horizontal direction, the laminated rubber 11 alone provides seismic isolation, and furthermore, in the case of vertical and horizontal seismic motion, the support plate 2 and the laminated rubber 11 are independent of each other. Since it is possible to perform good seismic isolation in the vertical direction and the horizontal direction, it is possible to prevent the structure 5 from experiencing complicated vibrations in the vertical direction and the horizontal direction.

Further, by adjusting the number of stacked support plates 2 or the tightening force of the stacked support plates 2, the vertical damping force of the structure 5 can be easily adjusted.

FIG. 11 is a side view showing a seismic isolation device according to a third embodiment of the present invention. As shown in this figure, this seismic isolation device 20
, a plurality of metal support plates 2 (four in the figure) having different diameters and formed in the shape of a disc, which performs seismic isolation in the vertical direction;
It is comprised of a horizontal seismic isolation device 30 that performs seismic isolation in the horizontal direction and is disposed below the seismic isolation device.

The support plate 2 has elasticity only in the vertical direction (thickness direction) and equal rigidity in both orthogonal directions, and is laminated so that the diameter increases from the lower end side to the upper end side. Tightening is fixed by a plurality of fixing metal fittings 3 such as bolts.

The horizontal seismic isolation device 30 includes a rolling plate 3 fixed on the foundation 4.
A plurality of ball bearings 32 that move freely on one
a spring 35a disposed between fixtures 34a and 34b provided on both sides of the trolley 33 and outside thereof;
35b, and horizontal movement of the cart 33 is limited by the spring force of the springs 35a and 35b.

The support plate 2a at the lower end is fixed to the support stand 36 fixed on the trolley 33 by a fixing fitting 3 that tightens and fixes the support plate 2, and the support plate 2b at the upper end is attached to the lower part of the structure 5 by bolts 8. is fixed.

The seismic isolation device 20 according to this embodiment is configured as described above, and in response to vertical seismic motion, the support plate 2 vibrates in the vertical direction to perform seismic isolation as described above, and in the horizontal direction. For earthquake motion, the trolley 3 equipped with ball bearings 32
3 performs seismic isolation by moving against the spring force of springs 35a and 35b.

In this manner, in this embodiment as well, seismic isolation in the vertical direction and in the horizontal direction can be independently and efficiently performed as described above.

FIG. 12 is a diagram showing the deflection-restoring force characteristics of the support plate 2 in each of the above-mentioned examples. A, B, C,
Draw the history of D, E, F, A, and draw this history (A, B, C,
The area within D, E, F, and A) becomes the vibration absorption energy.

As described above, since the support plate 2 is fixedly tightened by the fixing metal fittings 3, vertical vibration of the support plate 2 generates a frictional force in the surface direction between adjacent surfaces, and the vibration energy is unified. This allows for more efficient vertical seismic isolation.

In addition, in each of the above embodiments, the support plates 2 for seismic isolation in the vertical direction were formed into disk shapes with different diameters and stacked, but the support plates 2 formed with approximately the same diameter are not limited to this. They may be laminated, and the support plate 2 may have a polygonal shape that has equal high rigidity in any horizontal (or any direction within the horizontal plane) direction as well as in the horizontal direction.

[Effects of the Invention] As described above in detail based on the embodiments, according to the present invention according to claim 1, a plurality of laminated materials having elasticity only in the vertical direction and equal rigidity in any direction in the horizontal plane are provided. By supporting the structure with a supporting plate, it is possible to perform effective seismic isolation against vertical seismic motion.

Further, according to the present invention according to claim 2, seismic isolation is performed by the support means having elasticity only in the horizontal direction against earthquake motion in the horizontal direction, and seismic isolation is performed only in the vertical direction against earthquake motion in the vertical direction. By performing seismic isolation using a plurality of laminated support plates that are elastic and have equal rigidity in any direction in the horizontal plane, seismic isolation in the horizontal direction and in the vertical direction can be independently and efficiently performed. Further, since the support plate has high rigidity against torsional deformation, it is possible to suppress rocking vibrations from occurring in the structure even in the case of vertical and horizontal earthquake motions.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIGS. 1(a) and 1(b) are a side view and a plan view, respectively, showing a seismic isolation device according to a first embodiment of the present invention, and FIG. FIGS. 3 and 4 are side views showing the seismic isolation device interposed between the structure and the foundation, and FIG. 5(a) is a side view showing the operating state of the seismic isolation device. (b) is a side view and a plan view respectively showing a seismic isolation device according to a second embodiment of the present invention, and FIG. 6 shows a state in which the seismic isolation device is interposed between a structure and a foundation. The side view, Fig. 7 to Fig. 10 is a side view, Fig. 1, showing the operating state of the seismic isolation device.
1 is a side view showing a seismic isolation device according to a third embodiment of the present invention, and FIG. 12 is a side view showing a seismic isolation device according to a third embodiment of the present invention. Second. A diagram showing the deflection-restoring force characteristics of the support plate that performs vertical seismic isolation in the third embodiment, No. 13
The figure is a schematic diagram showing a seismic isolation device interposed between a structure and a foundation, FIGS. 14 to 19 are side views showing a conventional seismic isolation device, and FIGS. 20 and 21 are , respectively, are side views showing a state in which a conventional seismic isolation device is twisted when activated. 1.10.20...Seismic isolation device 2...Support plate 3...Fixing metal fittings 4...Foundation 5...Structure 11...Laminated rubber
30...Horizontal eel release device 32...Ball bearing 33...Dolly 25a, 35b-...Spring

Claims (4)

[Claims] (1) Between the structure and the foundation on the ground, the lower part is fixed to the upper part of the foundation and the upper part is fixed to the lower part of the structure, and has elasticity only in the vertical direction and can move in any direction in the horizontal plane. A seismic isolation device characterized in that a plurality of support plates having substantially equal rigidity are laminated and interposed. (2) A first support means having elasticity only in the horizontal direction, the lower part of which is disposed on the foundation, is disposed between the structure and the foundation on the ground, and the lower part is fixed to the upper part of the support means. and a second support means formed by laminating a plurality of support plates whose upper part is fixed to the lower part of the structure and which has elasticity only in the vertical direction and approximately equal rigidity in any direction in the horizontal plane. Characteristic seismic isolation device. (3) The support plate is formed into a disk shape, and a plurality of support plates are laminated on a coaxial line and fixed by tightening with a plurality of fixing metal fittings passing through the center of each support plate. The seismic isolation device according to claim 1 or 2. (4) The seismic isolation device according to claim 3, wherein the disk-shaped support plates are stacked such that the diameter increases from the lower end on the foundation side to the upper end on the structure side.