JP5181269B2 - Vertical seismic isolation mechanism - Google Patents

Description

  The present invention relates to a seismic isolation mechanism applied to a seismic isolation structure, and in particular, is installed between an upper structure and a lower structure to obtain a seismic isolation effect with respect to the relative vibration in the vertical direction between them. Regarding the mechanism.

In general, the seismic isolation structure is effective for horizontal motion but has little effect on vertical motion. This is because the vertical stiffness of the seismic isolation device is extremely large, 1000 times the horizontal stiffness, and the vertical damping is small.
Therefore, a vertical seismic isolation device using an air spring or a disc spring is considered as an effective seismic isolation structure for vertical motion. Patent Document 1 uses both a vertical seismic isolation device using a disc spring and a horizontal seismic isolation device in combination. There is disclosure about 3D seismic isolation devices.
JP 2001-82542 A

However, with the vertical seismic isolation device using air springs or disc springs, it is inevitable to increase the size of the building in order to stably support the weight of the entire building with air springs or disc springs, and the cost is also high. I can't say that.
In any case, the displacement amplitude of the vertical movement is orders of magnitude smaller than that of the horizontal movement, but an effective damper (attenuator) with a small amplitude and a large burden has not been put into practical use. In order to effectively actuate the damper by effectively operating the damper with respect to a minute vertical movement, it is necessary to reduce the vertical rigidity and increase the displacement amplitude of the vertical movement. However, if the vertical rigidity is excessively reduced, a “fluffy spring” state is caused, and the usual usability and comfort are greatly impaired.

From the above, in order to demonstrate the seismic isolation effect for vertical motion, it has sufficient supporting force to cope with the large vertical load of the superstructure, has moderately reduced vertical rigidity, and is effective from minute amplitude The performance of having a damping performance is required, but at present, an effective and appropriate vertical seismic isolation device that can meet such a demand is not provided.
In view of the above circumstances, an object of the present invention is to provide an effective and appropriate vertical seismic isolation mechanism having the above-described performance.

  The invention according to claim 1 is a vertical seismic isolation mechanism that obtains a seismic isolation effect with respect to the vertical relative vibration generated between the upper structure and the lower structure, wherein either the upper part or the lower part is horizontal. The upper structure and the lower structure are symmetrically arranged with at least one pair of substantially wedge-shaped movable members that are inclined with respect to each other and the other is a horizontal surface, with one end of each movable member facing each other. The inclined surface of each movable member is supported between the upper structure and the lower structure by an inclined sliding support so that the movable member can be displaced in the horizontal direction, and the horizontal surface of each movable member is supported by the horizontal sliding support. By supporting the lower structure or the upper structure so as to be displaceable in the horizontal direction, both of the movable members are supported by the slanted sliding support when a vertical displacement occurs between the upper structure and the lower structure. And on horizontal sliding bearings Ri and guided to be displaced in a horizontal direction opposite to mutually separating, and is characterized in that one end each other of both the movable member formed by connecting the spring element.

  A second aspect of the present invention is the vertical seismic isolation mechanism according to the first aspect of the present invention, wherein the damping force against the relative vibration in the vertical direction between the upper structure and the lower structure is caused by the frictional resistance force in the inclined sliding bearing. The friction coefficient in the inclined sliding bearing is set so that the friction coefficient in the horizontal sliding bearing is set smaller than the friction coefficient in the inclined sliding bearing, and the upper structure is moved to the lower structure by the horizontal sliding bearing. It is characterized by being supported so as to be relatively displaceable in horizontal directions.

The invention according to claim 3 is a vertical seismic isolation mechanism that obtains a seismic isolation effect with respect to the vertical relative vibration generated between the upper structure and the lower structure, wherein both the upper part and the lower part are horizontal. Using at least one pair of substantially wedge-shaped movable members inclined at the same angle in opposite directions, symmetrically arranged with one end of both movable members facing each other, the upper structure and the lower structure Between the upper structure and the lower structure by supporting the upper and lower inclined surfaces of each movable member in a horizontal direction with respect to the upper structure and the lower structure by means of inclined sliding bearings. When a relative displacement in the vertical direction occurs between the two movable members, both movable members are guided by the upper and lower inclined sliding bearings and can be displaced in the opposite horizontal direction so as to be separated from each other, and one end of both movable members How connected by a spring element The friction coefficient in the inclined sliding bearing is set so as to obtain a damping force against the relative vibration in the vertical direction between the upper structure and the lower structure by the frictional resistance force in the inclined sliding bearing, and the lower structure and A horizontal seismic isolation mechanism is provided between the supporting base and a base structure that supports the lower structure so as to be relatively displaceable relative to the base in each horizontal direction.

According to the vertical seismic isolation mechanism of the present invention, a pair of substantially wedge-shaped movable members are interposed between an upper structure and a lower structure so as to be horizontally displaceable via an inclined sliding bearing, and these movable members are movable. By connecting the members with spring elements, the vertical rigidity of the upper structure can be arbitrarily set by setting the inclination angle and the spring rigidity while supporting the vertical load of the upper structure via the movable member. By doing so, the natural period in the vertical direction can be lengthened, and the seismic response can be greatly reduced.
Also, by appropriately setting the coefficient of friction in the inclined sliding bearing that supports the movable member so as to be displaceable, hysteresis absorption energy is generated by the frictional resistance, and the sliding bearing itself functions as a damper (damping device). In addition, an excellent damping effect can be obtained without requiring any special damping element, and the damping characteristics can be freely and widely set by setting the inclination angle and the friction coefficient in the sliding bearing.
Furthermore, the upper structure can be supported by a horizontal sliding bearing with a sufficiently small coefficient of friction so that the upper structure can be displaced horizontally, or the lower structure (that is, the entire vertical seismic isolation mechanism) can be supported by the horizontal seismic isolation mechanism. As a whole, a three-dimensional seismic isolation mechanism can be configured, and not only a vertical seismic isolation effect but also a horizontal seismic isolation effect can be obtained.

  FIG. 1 shows a basic configuration of a vertical seismic isolation mechanism according to an embodiment of the present invention. The vertical seismic isolation mechanism of the present embodiment is installed between the upper structure 1 (for example, the main body of the base isolation building) and the lower structure 2 (for example, the foundation) that supports the vertical structure, and the vertical motion generated between them. A seismic isolation effect is obtained against relative vibrations in the direction.

  The vertical seismic isolation mechanism of the present embodiment uses a pair of substantially wedge-shaped movable members 3 whose upper part is inclined with respect to the horizontal and whose lower part is a horizontal plane. In the example shown, the base end side having a large height dimension is arranged symmetrically with each other facing each other and interposed between the upper structure 1 and the lower structure 2, and the inclined surfaces of the movable members 3 (see FIG. In the example shown, the upper surface) and the horizontal surface (the same lower surface) are supported by an inclined sliding bearing 4 and a horizontal sliding bearing 5 so as to be displaceable in the horizontal direction with respect to the upper structure 1 and the lower structure 2, respectively. Can be displaced so as to be separated from each other, and one end of each of the movable members 3 is connected by a spring element 6.

  The inclination angle θ with respect to the horizontal of the upper inclined surface of each movable member 3 may be set as appropriate. For example, it is preferable that tan θ is about 1/2 to 1/5. In the illustrated example, an inclined surface having the same angle is formed on the bottom surface of the upper structure 1 corresponding to the inclination angle θ.

The inclined sliding bearing 4 and the horizontal sliding bearing 5 are supported by a sliding material in which a smooth sliding surface made of, for example, stainless steel is covered with a resin having a low friction coefficient (for example, Teflon (registered trademark)) while supporting a vertical load. The sliding (sliding) mechanism is configured so as to be able to move relatively smoothly on a straight line. In the present embodiment, as will be described later, a desired damping force is obtained by the frictional resistance force on the inclined sliding bearing 4 on the upper surface side. The friction coefficient μ ₁ is appropriately set. The value of the friction coefficient μ ₁ is preferably about μ ₁ = 0.03 to 0.1, for example.
Further, the friction coefficient μ ₂ in the horizontal sliding bearing 5 on the lower surface side is made as small as possible (substantially zero), and the upper structure 1 is slid smoothly in each horizontal direction together with the movable member 3. Accordingly, the vertical seismic isolation mechanism of the present embodiment can obtain a seismic isolation effect not only in the vertical direction but also in the horizontal direction, and substantially functions as a three-dimensional seismic isolation mechanism.

The spring element 6 connecting the movable members 3 expands and contracts as the movable members 3 come in contact with each other to give a desired vertical rigidity. In the illustrated example, the movable member 3 serves as the spring element 6. A push spring that constantly urges each other outward is used.
In the illustrated example, the spring element 6 is shown as a coil spring, but the form and material of the spring element 6 may be appropriate as long as the spring element 6 has a desired spring rigidity. In any case, since the spring element 6 only expands and contracts in the horizontal direction and does not rotate with respect to the movable member 3, the connection to the movable member 3 is simply fixed without using a complicated joining mechanism such as a clevis or a ball joint. Just do it.

The vertical seismic isolation mechanism of the present embodiment is displaced in the opposite horizontal direction so that the movable members 3 come into contact with each other when vertical relative vibrations occur between the upper structure 1 and the lower structure 2. In addition, the elastic biasing force of the spring element 6 becomes a restoring force and is restored to the original position.
That is, in the illustrated example, when the upper structure 1 and the lower structure 2 are relatively displaced so as to approach each other (that is, the distance between the upper structure 1 and the lower structure 2 when the upper structure 1 is displaced downward). Each of the movable members 3 is pushed inward so as to approach each other while compressing it against the spring element 6. Conversely, when the upper structure 1 and the lower structure 2 are relatively displaced so that they are separated from each other (that is, when the upper structure 1 is displaced upward and the distance between the lower structure 2 increases). The movable members 3 are pushed outward by the elastic biasing force of the spring element 6 so as to be separated from each other.

At that time, the horizontal displacement δx between the movable members 3 is enlarged 2 / tanθ times the vertical relative displacement δz, and the vertical reaction force acting on the upper inclined sliding bearing 4 and the lower horizontal sliding bearing 5 is applied. Of the horizontal force acting between the movable members 3 if there is no friction. Therefore, the spring stiffness in the vertical direction is expanded by 4 / tan ² θ times the actual spring stiffness k of the spring element 6 installed between the movable members 3 by this mechanism. For example, when the inclination angle tan θ = 1/5, the vertical spring stiffness K is 100 times the actual spring stiffness k of the spring element.

Further, since the given predetermined frictional coefficient mu ₁ to the inclined sliding bearings 4, not slide until the vertical movement has a predetermined size, exerts a seismic isolation effect from beyond a certain size. Therefore, it does not become a “fluffy spring state” in which the upper structure vibrates sensitively due to a small excitation force such as walking or moving a car.
In addition, it is possible to arbitrarily set the degree of displacement from which the sliding starts to exert the seismic isolation effect by the inclination angle θ and the friction coefficient μ ₁ of the inclined surface, and formulate the value of the damping constant at that time by the method described later can do.

  In addition, since the spring stiffness in the vertical direction is increased with respect to the actual spring stiffness k of the spring element 6 connecting the movable members 3, the excessive deformation (sinking) does not occur. In addition, the restoring force of the spring element 6 does not cause a large residual deformation after the earthquake.

Hereinafter, the seismic isolation principle by the vertical seismic isolation mechanism of this embodiment, its analysis method, and an analysis result are demonstrated in detail with reference to FIGS.
In the following examination, the inclination angle of the upper inclined surface of the movable member 3 is θ, and the friction coefficient at the inclined sliding bearing is μ. The coefficient of friction at the lower horizontal sliding bearing is sufficiently small and can be ignored. Also, the vertical load is P, and therefore the vertical force on one side is P / 2, the reaction force of the inclined surface (acting in a direction perpendicular to the inclined surface) is N, the spring reaction force is f, and the spring stiffness of the spring element 6 is k. The vertical displacement is δz, the horizontal displacement (expansion / contraction amount) of the movable member 3 is δx, and its own weight is Po.
As shown in FIG. 2, in the case of horizontal displacement in a direction in which the spring reaction force is increased while receiving frictional resistance in the vertical direction (direction in which the movable members 3 approach each other), 1) Equation is derived.

On the contrary, as shown in FIG. 3, in the case where the load is unloaded while receiving frictional resistance in the vertical direction and the spring reaction force is reduced (the direction in which the movable members 3 are separated) is horizontally displaced (2 ) Formula is derived.

When the frictional force does not act, the equation (3) is obtained with the friction coefficient μ = 0 on the inclined surface in the equations (1) and (2).

The above results are shown in FIG. As shown in FIG. 4A, the rigidity of the equation (1) showing the behavior at the time of loading (displacement in the load direction) is high with reference to the equation (3) when there is no friction. The rigidity of the equation (2), which shows the behavior at the time (when the load decreases and is displaced (restored) in the reverse direction of the load), becomes low.
In addition, the “load and deformation history characteristics” in the case of vertical vibration exhibit a loop shape as shown in FIG. That is,
-From the state where the displacement δo due to its own weight Po occurs, the displacement does not change and the load increases until it hits the equation (1).
・ When load P further increases, it moves on the line of equation (1).
・ When the load P starts to decrease, the displacement does not change and the equation (2) is reached. If the load increases before reaching Equation (2), the load goes to Equation (1) parallel to the Y axis.
・ If load P is further reduced, it moves toward the origin on the line of equation (2).
・ When the load P starts to increase, the displacement does not change and the equation (1) is reached.
・ When load P further increases, it moves on the line of equation (1) (hereinafter repeated).

Since it has such hysteresis characteristics, when it vibrates up and down, hysteresis absorbs energy (corresponding to the area inside the square hysteresis loop shown in FIG. 4B) due to friction, and exhibits a vibration damping function.
In this case, the initial absorption K in the vertical direction when there is no friction, the initial displacement δo due to its own weight Po, the amplitude a, and the history absorption energy W when the vibration is up and down at each frequency ω is expressed by the following equation.

Further, as shown in FIG. 4B, when the equivalent stiffness at the amplitude (−a to + a) is K ′, the vertical vibration is determined by the equivalent stiffness K ′ and the mass m supported thereby. The equivalent attenuation coefficient is Ceq, the attenuation constant is heq, and the energy W absorbed by the attenuation can be expressed by the following equation. By making this equal to the above equation, the attenuation constant heq can be expressed as equation (4) Desired.

FIG. 5 shows an example of the result of calculating the equivalent attenuation constant heq by setting several specifications by the above analysis. (A) is an example when the tilt angle is 1/5, that is, tan θ = 0.2, and (b) is an example when the tilt angle is 1/2, that is, tan θ = 0.5.
As shown in FIG. 5, the damping tends to decrease as the amplitude increases. However, the damping constant heq is set to 0.1 to 0.2 by setting the friction coefficient μ in the inclined sliding bearing to about 0.05 to 0.1 as in the normal sliding bearing. It turns out that it can be made into a grade. In other words, in the case of normal structural damping without a special damping device, the damping constant is only about 0.01. However, according to this mechanism, sufficient damping performance for suppressing vertical vibrations can be provided. I understand.

The above analysis is organized based on the displacement amplitude, but when organized by stress amplitude (axial force fluctuation), if the stress amplitude ΔP where slip does not occur due to displacement δo is in the range of Since no hysteresis loop is drawn while the displacement remains δo, no attenuation can be imparted and heq = 0.

When the stress amplitude is further increased, a hysteresis loop is drawn. In this case, ΔP and a / Δo are obtained by the following equations.

Then, by substituting a / δo obtained above into the equation (4), an equivalent attenuation constant heq can be obtained by the following equation. ΔP / Po is a stress amplitude ratio (response axial force / self-weight).

FIG. 6 shows the result of calculating the equivalent attenuation constant heq in the same manner as the displacement amplitude by the above analysis. As is clear from FIG. 6, the smaller the inclination angle θ and the larger the friction coefficient μ, the greater the stress amplitude at which the damping effect begins to be exhibited (that is, the slip amplitude does not start unless the stress amplitude becomes large, and the effect begins to be effective). Become slow). To give a specific example, when the inclination angle θ is 1/2 (see FIG. 6B) and the friction coefficient is μ = 0.05, the stress axial force starts to be effective from 0.13 times its own weight Po. The attenuation constant is 0.1 or more up to 0.8 times Po, and a response reduction effect can be expected over a wide range.
Further, since the spring stiffness k is not included in the expression of the damping constant heq, it can be seen that the damping constant heq does not depend on the spring stiffness k.

As mentioned above, although the vertical seismic isolation mechanism of this embodiment was demonstrated, the effect is enumerated below.
(1) Damping by frictional force only by placing a simple sliding bearing slightly inclined with respect to the horizontal without using complicated and expensive linear motion mechanisms (linear guides) and damping devices such as oil dampers Force can be obtained, and it can sufficiently cope with a large vertical load. Therefore, it is possible to realize a high-performance vertical seismic isolation mechanism with a simple configuration and low cost.
(2) Since the sliding bearing has a predetermined coefficient of friction, it does not slide against minute vibrations and does not exhibit a seismic isolation effect. For this reason, a so-called “fluffy spring” state that does not sway sensitively by walking or moving the car at all times is not obtained. Of course, when a large earthquake occurs, slipping occurs and the frictional resistance is used for damping, so that the response can be sufficiently reduced, and it functions effectively as a vertical seismic isolation mechanism.
(3) Generally, the vertical displacement due to vertical movement is substantially the same at all the support positions. If the spring stiffness k of the spring element 6 in the bearing is set so that the vertical displacement of the bearing due to constant load (axial force) is uniform (so that it does not sink unevenly), the stress amplitude ratio ΔP / Po is also the same. Become. In this case, since the stress amplitude ratio ΔP / Po at the start of sliding is determined by the following equation, it does not change as long as the friction coefficient μ and the inclination angle θ are constant regardless of the spring stiffness k. Therefore, if the friction coefficient μ and the inclination angle θ of the inclined surface are made the same in all the bearings, the sliding starts simultaneously and the same vertical vibration can be caused.

(4) The damping constant heq does not depend on the spring stiffness k of the spring element 6 (it does not change depending on the value of the spring stiffness k). Therefore, if the friction coefficient μ and the inclination angle θ of the inclined surface are the same in all the bearings, it is possible to have a damping force proportional to the axial force.
(5) The stress amplitude ratio at the time when the effect of the vertical motion isolation is started (sliding) can be arbitrarily set by the friction coefficient μ and the inclination angle θ of the inclined surface.
In order to be effective from the case where the stress amplitude ratio ΔP / Po is small, it is only necessary to decrease the friction coefficient μ and increase the inclination angle θ, but in this case, when the stress amplitude ratio ΔP / Po increases. The attenuation constant heq becomes smaller. Therefore, by setting the lower limit of the stress amplitude ratio ΔP / Po in which vertical motion becomes a problem so as to begin to slip, vertical vibration for earthquake motion larger than this can be significantly reduced.
In addition, when the stress amplitude ratio ΔP / Po increases, the damping constant heq decreases in inverse proportion to this, and the response reduction effect also decreases, but in any case, the equivalent damping constant heq is easily secured above 0.1. can do. In other words, considering that the damping constant for vertical vibrations in a general structure is only about 0.01, it is possible to secure a damping performance of 10 times or more, and a significant response reduction effect can be obtained.

(6) Since all the bearings vibrate in the same vertical direction, the energy absorption efficiency is high and no excessive stress is generated on the base of the seismic isolation layer. If the vertical displacement of adjacent bearings is different, a large stress due to forced displacement is generated in the lower structure 2 (usually the foundation beam is equivalent to this), but it is easy to make the vertical displacement of all the bearings the same. Since it can be set, such stress does not occur.
(7) Since the spring element 6 that connects the movable members 3 to each other in the support is present, when the vibration is settled by the spring stiffness k, the spring element 6 is restored to the original position, so that residual deformation is reduced.
(8) The vertical stiffness after the occurrence of slipping is determined by the spring stiffness k of the spring element 6, but it can be significantly lower than the conventional seismic isolation, so that the vertical motion is longer and the seismic response Is greatly reduced.
(9) Since not only the vertical isolation by the inclined sliding bearing 4 but also the horizontal isolation effect by the horizontal sliding bearing 5 can be obtained at the same time, a three-dimensional seismic isolation mechanism as a whole is obtained.

Although one embodiment of the present invention has been described above, another embodiment is shown in FIG.
FIG. 7 (a) is a reverse configuration of the whole top and bottom. That is, the upper part of the movable member 3 is horizontally supported by the horizontal sliding support 5 with respect to the bottom surface of the upper structure 1 with the horizontal slide support 5, and the lower structure 2 is supported by the inclined sliding support 4 with the lower part of the movable member 3 as the inclined surface. It is supported so as to be horizontally displaced with respect to the upper surface. In this case, the friction coefficient μ ₁ in the upper horizontal sliding bearing 5 is made as small as possible, and the friction coefficient μ ₂ in the lower inclined sliding bearing 4 is set so as to obtain a desired damping. The same effect as the form can be obtained.

FIG. 7 (c) shows another embodiment, and FIG. 7 (b) shows its basic configuration. That is, in FIG. 7B, both the upper and lower parts of the movable member 3 are inclined surfaces, and both of the inclined surfaces are supported by the inclined sliding bearing 4 so as to be horizontally displaceable. A sufficient damping force can be obtained by setting the friction coefficient. However, in this case, since the horizontal relative displacement between the upper structure 1 and the lower structure 2 is restrained by the movable member 3, a horizontal seismic isolation effect cannot be expected, and only when it is unnecessary.

Therefore, FIG. 7 (c) further shows a structure in which the lower structure 2 is supported in the horizontal direction with respect to the base 7 via the horizontal seismic isolation mechanism 8, that is, the entire vertical seismic isolation mechanism shown in FIG. A three-dimensional seismic isolation mechanism is constructed as a whole in support of horizontal seismic isolation. In this case, as the horizontal seismic isolation mechanism 8 for isolating and supporting the entire vertical seismic isolation mechanism, not only horizontal sliding bearings but also rolling bearings such as bearing bearings and roller bearings, laminated rubber or the like can be adopted.

  In FIG. 7D, the movable member 3 is turned in the opposite direction to the above examples, the tips having small heights are opposed to each other, and a pulling spring that constantly urges the movable members 3 inward is used as the spring element 6. It was. In this case, when the upper structure 1 is displaced downward, each movable member 3 is pushed outward so as to be separated from each other while extending the spring element 6 against the spring element 6, and the upper structure 1 is moved upward. When displaced, the movable members 3 are attracted inward so as to approach each other by the urging force of the spring element 6 and function in the same manner as in the above examples only in the reverse direction of operation. Of course, in this case as well, the position of the inclined surface is arbitrary, and the lower surface is not limited to the inclined surface as shown, but the inclined surface is the lower portion as shown in FIGS. It goes without saying that both the upper part and the lower part may be used.

  In each of the above examples, the movable members 3 are used as one-to-two units, but two-to-four movable members are arranged in an orthogonal direction, or a large number of pairs of movable members are arranged radially. It can also be arranged in the direction.

It is a schematic block diagram which shows the vertical seismic isolation mechanism which is one Embodiment of this invention. It is a figure which shows the example of an analysis same as the above. It is a figure which shows the example of an analysis same as the above. It is a figure which shows the example of an analysis same as the above. It is a figure which shows an analysis result similarly. It is a figure which shows an analysis result similarly. It is a figure which shows other embodiment same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Upper structure 2 Lower structure 3 Movable member 4 Inclined sliding bearing 5 Horizontal sliding bearing 6 Spring element 7 Base 8 Horizontal seismic isolation mechanism

Claims (3)

A vertical seismic isolation mechanism that obtains a seismic isolation effect with respect to the vertical relative vibration generated between the upper structure and the lower structure,
With at least one pair of substantially wedge-shaped movable members in which either the upper part or the lower part is inclined with respect to the horizontal and the other is a horizontal surface, the ends of both movable members are opposed to each other. Symmetrically placed between the upper structure and the lower structure,
The inclined surface of each movable member is supported so as to be horizontally displaceable with respect to the upper structure or the lower structure by an inclined sliding support, and the horizontal surface of each movable member is supported against the lower structure or the upper structure by a horizontal sliding support. In this way, when the relative displacement in the vertical direction occurs between the upper structure and the lower structure, both movable members are guided by the inclined sliding bearing and the horizontal sliding bearing so that they are mutually supported. Displaceable in the opposite horizontal direction so as to be separated,
A vertical seismic isolation mechanism characterized in that one end of both movable members is connected by a spring element. The vertical seismic isolation mechanism according to claim 1,
Set the coefficient of friction in the inclined sliding bearing so as to obtain a damping force against the relative vibration in the vertical direction between the upper structure and the lower structure by the frictional resistance force in the inclined sliding bearing,
In addition, the friction coefficient in the horizontal sliding bearing is set to be smaller than the friction coefficient in the inclined sliding bearing, and the upper structure is supported by the horizontal sliding bearing so as to be relatively displaceable relative to the lower structure in each horizontal direction. A vertical seismic isolation mechanism. A vertical seismic isolation mechanism that obtains a seismic isolation effect with respect to the vertical relative vibration generated between the upper structure and the lower structure,
Using at least one pair of substantially wedge-shaped movable members whose upper and lower surfaces are inclined at the same angle in the opposite direction with respect to the horizontal, they are arranged symmetrically with one end of both movable members facing each other. Interposing between the upper structure and the lower structure,
The upper and lower inclined surfaces of each movable member are supported by an inclined sliding support so as to be horizontally displaceable with respect to the upper structure and the lower structure. When the displacement occurs, both movable members can be displaced in the horizontal direction in the opposite direction so as to be guided by the upper and lower inclined sliding bearings and separated from each other,
And, one end of both movable members are connected by a spring element ,
Set the coefficient of friction on the inclined sliding bearings to obtain a damping force against vertical relative vibrations between the upper structure and the lower structure by the frictional resistance on the inclined sliding bearings,
In addition, a vertical seismic isolation mechanism is provided between the lower structure and the base that supports it, and a horizontal seismic isolation mechanism that supports the lower structure so as to be relatively displaceable relative to the base in each horizontal direction. Seismic isolation mechanism.

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