JP7423901B2 - Structure and structure design method - Google Patents

Description

The present invention relates to a structure and a method of designing a structure.

As a structure equipped with a seismic isolation device, Patent Document 1 discloses that a sliding bearing and an elastic bearing are arranged overlappingly between an upper structure and a lower structure, and that the resistance force increases as the amount of sliding due to the sliding bearing increases. A structure is described in which a resistance member is provided between a wall of an upper structure and a wall of a lower structure.

Patent No. 63-32036

In the structure described above, the resistance force of the resistance member increases as the amount of slip increases, so there is a possibility that suitable control cannot be performed in accordance with the input level of external force. For example, it has been difficult to achieve ultra-long-period seismic isolation with a seismic isolation period of 10 seconds or more, which exceeds the typical seismic isolation period of 3 to 5 seconds. Furthermore, it was not possible to deal with excessive input that exceeded the design level.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to perform suitable control according to the input level of external force.

The main invention for achieving the above object includes: an upper structure having an upper structure wall; a lower structure having a lower structure wall facing the upper structure wall with a predetermined distance in the horizontal direction; A support structure provided between the upper structure and the lower structure and supporting the upper structure so as to be relatively displaceable in the horizontal direction with respect to the lower structure, and between the upper structure wall and the lower structure wall. an intervening member interposed in the upper structure wall, the other end in the axial direction being fixed to one of the upper structure wall part or the lower structure wall part, the other end in the axial direction being fixed to one of the upper structure wall part or the lower structure wall part; an intervening member that abuts the other wall, the intervening member being able to withstand a small earthquake or a In the first region where the amount of approaching displacement during wind load is from 0 to the first amount of displacement , elastic deformation in the axial direction, that is, axial deformation, provides a predetermined rigidity in the axial direction, and is suitable for moderate earthquakes and In a second region where the approaching displacement amount in a large earthquake extends from the first displacement amount to a second displacement amount exceeding the first displacement amount , deformation occurs in an out-of-plane direction intersecting the axial direction, that is, geometric In a third region where the reduced stiffness is lower than the predetermined stiffness in the axial direction due to the nonlinearity , and the approaching displacement amount exceeds the second displacement amount when exceeding the design level , The horizontal length of the intervening member is the same as that of the upper structure and the lower structure in a state where the upper structure and the lower structure are not displaced relative to each other in the horizontal direction. The dimension of the gap in the horizontal direction is the same as that of the horizontal gap, and the intervening member can maintain elasticity even after deformation, and by reversing the direction of the external force, the upper structure and the lower structure can be aligned horizontally. In a state in which there is no relative displacement in the direction, the other end in the axial direction is restored to its original state while remaining in contact with the other of the upper structure wall portion or the lower structure wall portion .

Other features of the present invention will become apparent from the description of this specification and the accompanying drawings.

According to the present invention, suitable control can be performed according to the input level of external force.

FIG. 1 is a schematic diagram showing the configuration of a structure 1 according to the present embodiment. 5 is a schematic perspective view of a cushioning material 50. FIG. FIG. 3A is a diagram showing the history characteristics of the cushioning material 50A. FIG. 3B is a diagram showing the history characteristics when the bearing structure 40 is a rolling bearing. FIG. 3C is a diagram showing the history characteristics of the cushioning material 50B. FIG. 3D is a diagram showing the combined history characteristics of the support structure 40 and the cushioning material 50. FIGS. 4A to 4C are explanatory diagrams showing operations in a first region where shaking is relatively small. FIGS. 5A to 5C are explanatory diagrams showing operations in the second region where shaking is large. FIGS. 6A to 6D are explanatory diagrams showing the operation in the third region where the shaking is very large. FIG. 2 is a flowchart for explaining a method of designing the structure 1 (mainly the cushioning material 50). FIG. 6 is a diagram showing the relationship between the displacement of the buffer material 50 and the load. 9A and 9B are plan views showing the case where the system of this embodiment is applied to an actual building. FIG. 10A is a diagram showing a modification of the structure 1. FIG. 10B is a diagram showing the history characteristics of the damper 80. FIG. 10C is a diagram showing the overall history characteristics in the configuration of the modified example. It is a figure which shows the history characteristic when the bearing structure 40 is a friction sliding bearing.

From the description of this specification and the attached drawings, at least the following matters will become clear.
an upper structure having an upper structure wall; a lower structure having a lower structure wall facing the upper structure wall with a predetermined distance in the horizontal direction; and a lower structure provided between the upper structure and the lower structure. a support structure that supports the upper structure so as to be relatively displaceable in the horizontal direction with respect to the lower structure; and an intervening member interposed between the upper structure wall and the lower structure wall. , an intervening member having one axial end fixed to one of the upper structure wall or the lower structure wall, and the other axial end abutting the other of the upper structure wall or the lower structure wall; , wherein the intervening member has a first region in which, in a state where the upper structure wall portion and the lower structure wall portion approach each other due to an external force, a displacement amount of the approaching portion is up to a first displacement amount. has a predetermined rigidity in the axial direction, and in a second region where the approaching displacement amount is from the first displacement amount to a second displacement amount that exceeds the first displacement amount, the axial direction has a predetermined rigidity than the predetermined rigidity. A structure is revealed which is characterized by having a low reduced stiffness and being plastically deformed in a third region where the approaching displacement amount exceeds the second displacement amount.
According to such a structure, in the first region, it is possible to ensure livability and the soundness of the expansion joint, in the second region, it is possible to increase the seismic isolation period, and in the third region, A fail-safe mechanism can be realized. Thereby, suitable control can be performed according to the input level of external force.

In such a structure, it is desirable that the intervening member has resilience in the first region and the second region.
According to such a structure, residual displacement of the upper structure after an earthquake can be suppressed.

In such a structure, it is preferable that the interposed member is axially deformed in the axial direction in the first region.
According to such a structure, displacement of the upper structure with respect to the lower structure can be restrained, and comfort and soundness of the expansion joint can be ensured.

In such a structure, it is preferable that the interposed member deforms out of plane in a direction intersecting the axial direction in the second region.
According to such a structure, it is possible to deform in the axial direction under a constant axial force by deforming out of plane. This allows the stiffness (reduced stiffness) of the second region to be lowered, making it possible to lengthen the period or to make the period extremely long.

In such a structure, it is desirable that the intervening member has a hollow cylindrical portion.
According to such a structure, deformation (out-of-plane deformation) is likely to occur in the second region.

Further, an upper structure having a first wall portion, a lower structure having a second wall portion facing the first wall portion in the horizontal direction, and a lower structure provided between the upper structure and the lower structure, the upper structure a supporting structure that supports the lower structure so as to be relatively displaceable in the horizontal direction; and an intervening member interposed between the first wall part and the second wall part, the intervening member having one end attached to the first wall part. A method for designing a structure comprising: an intervening member fixed to one of a wall or the second wall, the other end of which abuts the other of the first wall or the second wall, determining various design conditions for the upper structure, the lower structure, and the supporting structure; designing the intervening member; and bringing the upper structure wall and the lower structure wall closer together due to an external force. In the state, the interposed member has a predetermined rigidity in the axial direction in a first region where the approaching displacement amount is up to the first displacement amount, and the approaching displacement amount is from the first displacement amount to the first displacement amount. In a second region up to a second displacement amount exceeding the second displacement amount, the interposed member has a reduced stiffness lower than the predetermined rigidity in the axial direction, and in a third region where the approaching displacement amount exceeds the second displacement amount. A method for designing a structure is made clear, comprising the step of confirming that the interposed member plastically deforms in the region.

===Embodiment===
<About the configuration>
FIG. 1 is a schematic diagram showing the configuration of a structure 1 of this embodiment. Moreover, FIG. 2 is a schematic perspective view of the cushioning material 50. In FIG. 1, one horizontal side (the right side in the figure) is the B side, and the other side (the left side in the figure) is the A side. Further, the direction along the vertical direction is defined as an up-down direction, the upper side in the vertical direction is defined as an upper side, and the lower side is defined as a lower side.

The structure 1 includes an upper structure 20, a lower structure 30, a support structure 40, and a cushioning material 50.

The superstructure 20 is, for example, a building, a floor, a device or structure such as a large device. The upper structure 20 of this embodiment has side walls 21 (corresponding to upper structure walls) at both ends in the horizontal direction. In the following description, the side wall 21 at the B side end in the horizontal direction of the upper structure 20 is also referred to as the side wall 21B, and the side wall 21 at the A side end in the upper horizontal direction is also referred to as the side wall 21A (see FIG. 1). The side wall 21A and the side wall 21B are side wall portions of the upper structure 20 and extend in the vertical direction (up and down direction).

The lower structure 30 is a structure that supports the upper structure 20 and transmits the load to the ground, and is provided below the upper structure 20. Further, the lower structure 30 extends outward from the upper structure 20 in the horizontal direction, and has retaining walls 31 (corresponding to lower structure walls) projecting upward at both ends thereof. In the following description, the retaining wall 31 at the B side end in the horizontal direction is also referred to as the retaining wall 31B, and the retaining wall 31 at the A side end in the upper horizontal direction is also referred to as the retaining wall 31A (see FIG. 1). The retaining wall 31B faces the side wall 21B of the upper structure 20, and the retaining wall 31A faces the side wall 21A of the upper structure 20. Further, a gap (gap D) of a predetermined size is provided in the horizontal direction between the retaining wall 31A and the side wall 21A, and between the retaining wall 31B and the side wall 21B.

The support structure 40 is provided between the lower surface of the upper structure 20 and the upper surface of the lower structure 30 (a gap in the vertical direction), and supports the upper structure 20 so as to be relatively displaceable in the horizontal direction with respect to the lower structure 30. ing. The support structure 40 of this embodiment is a rolling support using spheres, and the frictional force against the upper structure 20 and the lower structure 30 is very small. Note that the member constituting the rolling support is not limited to a sphere, and for example, a roller or the like may be used.

The buffer material 50 (corresponding to an intervening member) is provided in the gap D between the retaining wall 31 and the side wall 21. In addition, in the following description, the buffer material 50 provided between the retaining wall 31B and the side wall 21B is also referred to as a buffer material 50B, and the buffer material 50 provided between the retaining wall 31A and the side wall 21A is also referred to as a buffer material 50A. Also called (see Figure 1). However, the cushioning material 50A and the cushioning material 50B are members having the same configuration and are arranged symmetrically with respect to the upper structure 20.

As shown in FIG. 2, the cushioning material 50 of this embodiment has a cylindrical portion 51 having a cylindrical shape, and a hollow portion 51a is provided inside the cylindrical portion 51 along the axial direction. In the present embodiment, the hollow portion 51a penetrates both ends of the cushioning material 50 in the axial direction, but the invention is not limited to this. For example, the hollow portion 51a may be provided in a part of the cushioning material 50 in the axial direction. (a part of the cushioning material 50 may be the cylindrical portion 51). Moreover, although the cushioning material 50 of this embodiment has different diameters at both ends in the axial direction, the diameter is not limited to this and may be constant.

In the structure 1, the buffer material 50 is provided so that its axial direction is along the horizontal direction. Specifically, one end in the axial direction (the end on the larger diameter side) of the buffer material 50 is connected to the lower structure 30 (specifically, the inner surface of the retaining wall 31) via a flange (steel flange), etc. not shown. The other end in the axial direction (the end with the smaller diameter) is in contact with the upper structure 20 (specifically, the side wall 21). That is, the buffer material 50 is joined to the lower structure 30 but not to the upper structure 20. Further, in the initial state (the state in which the upper structure 20 and the lower structure 30 are not displaced relative to each other in the horizontal direction), the length of the cushioning material 50 in the axial direction (horizontal direction here) is the same as the dimension of the gap D. Further, as will be described later, the shape of the cushioning material 50 of this embodiment changes in three stages depending on the magnitude of input seismic motion (in other words, the magnitude of relative displacement between the upper structure 20 and the lower structure 30).

Table 1 shows an example of the performance (reaction force and absorbed energy) of the buffer material 50.

FIG. 3A is a diagram showing the hysteresis characteristics of the cushioning material 50A, and FIG. 3B is a diagram illustrating the hysteresis characteristics when the support structure 40 is a rolling bearing. Further, FIG. 3C is a diagram showing the history characteristics of the cushioning material 50B, and FIG. 3D is a diagram showing the history characteristics of the support structure 40 and the cushioning material 50 (the cushioning material 50A and the cushioning material 50B). In each figure, the horizontal axis indicates the amount of displacement (the amount of horizontal displacement of the upper structure 20 with respect to the lower structure 30), and the vertical axis indicates the magnitude of the load.

The cushioning material 50A of this embodiment has a substantially trapezoidal history characteristic as shown in FIG. 3A (this characteristic will be described later). Further, the cushioning material 50B also has a substantially trapezoidal history characteristic as shown in FIG. 3C. Note that the cushioning material 50A and the cushioning material 50B have the same configuration and are arranged symmetrically with respect to the upper structure 20 in the horizontal direction, so their history characteristics are symmetrical (symmetrical with respect to the origin).

Since the support structure 40 is a rolling support with almost no frictional force, no load is generated regardless of the amount of displacement, as shown in FIG. 3B.

By combining FIGS. 3A to 3C, the history characteristics of the structure 1 of this embodiment are as shown in FIG. 3D. The operation of the structure 1 of this embodiment will be described below.

<About operation>
FIGS. 4A to 4C are explanatory diagrams showing operations in a first region where shaking is relatively small (during wind loads or small earthquakes).

First, as shown in FIG. 4A, by receiving an external force (for example, an earthquake force) in the direction B, the upper structure 20 is displaced relative to the lower structure 30 in the horizontal direction B (the side wall 21B is a retaining wall). 31B). As a result, the cushioning material 50A is separated from the upper structure 20 (side wall 21A), and the cushioning material 50B is pushed in the axial direction by the upper structure 20 (side wall 21B) and elastically deforms. That is, the cushioning material 50B undergoes axial deformation in the axial direction, and its axial length becomes slightly shorter. The area where such deformation is performed is also referred to as a first area (see FIG. 8). In the first region, the buffer material 50 (here, the buffer material 50B) has high rigidity in the axial direction and suppresses horizontal deformation of the seismic isolation structure.

In FIG. 4B, the superstructure 20 has returned to its initial position (initial state) due to the direction of the seismic force being reversed. Note that by returning to the initial position, the cushioning material 50A comes into contact with the upper structure 20, and the cushioning material 50B is restored to its original shape (the length in the axial direction is the same as the dimension of the gap D).

Thereafter, by further receiving an earthquake force in the direction of the A side, the upper structure 20 moves horizontally to the A side as shown in FIG. 4C. The operation in this case is the same as that in FIG. 4A (however, the horizontal direction is reversed), so the explanation will be omitted.

As described above, during wind loads or small earthquakes (first region), the cushioning material 50 has high axial rigidity and undergoes elastic deformation (axial deformation) in the axial direction. This prevents unpleasant shaking and ensures comfortable living. In addition, the soundness of the expansion joint can be ensured.

FIGS. 5A to 5C are explanatory diagrams showing operations in a second region (during medium to large earthquakes) where shaking is large.

In FIG. 5A, the amount of displacement of the upper structure 20 in the horizontal direction B is larger than in FIG. 4A. That is, compared to FIG. 4A, the side wall 21B of the upper structure 20 is closer to the retaining wall 31B of the lower structure 30. At this time, as shown in FIG. 5A, the cushioning material 50 of this embodiment (here, the cushioning material 50B) deforms also in the out-of-plane direction when the predetermined displacement amount δ ₁ (corresponding to the first displacement amount) is exceeded. and bulges outward (the shape has geometric nonlinearity). The area where this transformation is performed is also referred to as a second area (see FIG. 8). In the second region, the axial rigidity of the cushioning material 50B is lower than in the first region (reduced rigidity). As a result, the cushioning material 50B becomes in a state where its displacement increases under a constant load, and the upper structure 20 becomes easier to move in the horizontal direction. Therefore, compared to the case where elastic deformation continues only in the axial direction, the load applied to the upper structure 20 (the load indicated by X in FIG. 5A) is reduced. Note that by using a material with high bending strength as the buffer material 50 (buffer material 50A, buffer material 50B), it is possible to maintain elasticity even after this deformation, and the residual displacement of the superstructure 20 after an earthquake can be reduced. It can be suppressed.

In FIG. 5B, the direction of the seismic force is reversed, so that the positional relationship between the upper structure 20 and the lower structure 30 has returned to the initial state, and the buffer material 50A is in contact with the upper structure 20 (side wall 21A). Moreover, since the cushioning material 50B maintains its elasticity, it restores to its original shape while remaining in contact with the side wall 21B.

The same applies to the case of displacement in the opposite direction (FIG. 5C) (however, the horizontal direction is reversed), so the explanation will be omitted.

In this way, during medium to large earthquakes with large shaking (second region), the buffer material 50 deforms in the out-of-plane direction (has geometric nonlinearity), thereby changing its shape in the axial direction (horizontal direction). Rigidity decreases. Thereby, the buffer material 50 exhibits performance equivalent to that of a general seismic isolation device, so long-period or ultra-long-period seismic isolation can be realized.

FIGS. 6A to 6D are explanatory diagrams showing the operation in the third region where the shaking is extremely large (exceeding the design level).

In FIG. 6A, the amount of displacement of the upper structure 20 in the horizontal direction B is even larger than in FIG. 5A. That is, compared to FIG. 5A, the side wall 21B of the upper structure 20 is closer to the retaining wall 31B of the lower structure 30. At this time, as shown in FIG. 6A, the cushioning material 50 (here, the cushioning material 50B) of this embodiment is crushed and plastically deformed when the predetermined displacement amount δ ₂ (corresponding to the second displacement amount) is exceeded. The area where this transformation is performed is also referred to as a third area (see FIG. 8). In this third region, the shock absorbing material 50 absorbs earthquake energy by plastically deforming, so that damage to the building (superstructure 20) can be suppressed. In this way, when the shaking exceeds the design level (third region), the buffer material 50B functions as a fail-safe mechanism to reduce the response of the upper structure 20, and the upper structure 20 (side wall 21B) to the retaining wall 31B reduce the impact of collisions. Note that if the cushioning material 50A is completely crushed, the displacement will not increase and the load will increase after that, but in FIG. It shows.

In FIG. 6B, the direction of the seismic force is reversed, so that the positional relationship between the upper structure 20 and the lower structure 30 has returned to the initial state, and the buffer material 50A is in contact with the upper structure 20 (side wall 21A). However, since the buffer material 50B is plastically deformed, it remains in the state shown in FIG. 6A. That is, the upper structure 20 (side wall 21B) and the buffer material 50B are spaced apart.

As shown in FIG. 6C, when the upper structure 20 is displaced in the opposite direction, the operation is similar to that in FIG. 6A (however, the direction is reversed). In this case as well, the shock absorbing material 50 (here, the shock absorbing material 50A) absorbs seismic energy by plastically deforming, so that damage to the building (superstructure 20) can be suppressed. That is, like the buffer material 50B in FIG. 6A, the buffer material 50A functions as a fail-safe mechanism and reduces the impact of the upper structure 20 (side wall 21A) colliding with the retaining wall 31A.

After that, as shown in FIG. 6D, the buffer materials 50 (buffer materials 50A and 50B) are plastically deformed and are no longer able to absorb energy, and the upper structure 20 only supports the support structure 40 (rolling support). It vibrates horizontally.

As described above, in the structure 1 of this embodiment, when the side wall 21 and the retaining wall 31 approach each other due to external force (seismic motion, etc.), the input level (relative displacement amount between the upper structure 20 and the lower structure 30 The cushioning material 50 deforms in three stages depending on the size of the trend.

During small earthquakes that occur frequently or wind loads (in the first region where the amount of approaching displacement is up to δ ₁ ), the cushioning material 50 undergoes axial deformation in the axial direction without any change in shape, and is in a state of high rigidity in the axial direction. maintain. This restricts the movement of the upper structure 20 and ensures comfort and durability of the expansion joint.

In addition, in a medium earthquake or a large earthquake (the second region where the approaching displacement amount is from δ ₁ to δ ₂ ), the displacement increases under a constant load by deforming the buffer material 50 in an out-of-plane direction (in the axial direction (low rigidity). In this state, the superstructure 20 can move in the horizontal direction, so long-period or very long-period seismic isolation can be achieved. Further, by using a material with high bending strength as the buffer material 50, it is possible to maintain elasticity even after out-of-plane deformation, and residual displacement of the upper structure 20 after an earthquake can be suppressed.

Furthermore, when the design level is exceeded (the third region where the amount of approaching displacement exceeds δ2), the shock absorbing material 50 is plastically deformed to absorb seismic energy (vibration energy of the upper structure 20). Thereby, the buffer material 50 functions as a fail-safe mechanism that reduces the response of the upper structure 20, and reduces the impact of the collision between the lower structure 30 (retaining wall 31) and the upper structure 20 (side wall 21).

<About the structure design method>
FIG. 7 is a flow diagram for explaining a method of designing the structure 1 (mainly the cushioning material 50). Moreover, FIG. 8 is a diagram showing the relationship between the displacement of the cushioning material 50 and the load. In addition, in FIG. 8, the buffer material 50 does not have rigidity in the second region (the load is constant), but it may have rigidity as long as it is lower than the rigidity in the first region. Furthermore, although the cushioning material 50 does not have rigidity in the third region, it may have rigidity to suppress excessive deformation.

First, various design conditions for the structure 1 are determined (S101). Specifically, the configuration (shape, size, etc.) of the upper structure 20 and lower structure 30, the weight M of the upper structure 20, the acceleration a in the first region (microground vibration level), the second region (medium to large earthquake vibration level), acceleration b of the ground motion level), acceleration c of the third region (earthquake motion level beyond design), etc. are determined. Furthermore, the dimensions of the gap (gap D) between the side wall 21 of the upper structure 20 and the retaining wall 31 of the lower structure 30 and the configuration of the support structure 40 (type of support, etc.) are also determined.

Next, a specific design of the cushioning material 50 is performed (S102). That is, the material, shape, and dimensions (height, diameter, length), etc. of the cushioning material 50 are determined.

Then, it is determined whether the cushioning material 50 satisfies various performance requirements (S103).
Here, for example, the following items are checked as various performances.

Note that F is the force (load) when the seismic isolation device starts moving. W is the attenuation amount (area of the trapezoidal part in Fig. 8), δ ₁ is the displacement amount (relative displacement amount) at the boundary between the first and second regions, and δ ₂ is the boundary between the second and third regions. is the amount of displacement (relative displacement). Further, T ₂ is the period of vibration in the second region, and T ₃ is the period of vibration in the third region.

Further, the ratio of δ ₁ to the length (D) of the cushioning material 50 {(δ ₁ /D)×100} is 5 to 40 (%), and the ratio of δ ₂ to the length (D) of the cushioning material 50 {( δ ₂ /D)×100} is 40 to 70 (%). Note that in the cushioning material 50 of this embodiment, {(δ ₁ /D)×100} is approximately 20%, and {(δ ₂ /D)×100} is approximately 50%.

According to such evaluation, in the first region, the cushioning material 50 has high rigidity in the axial direction, in the second region, the cushioning material 50 has low rigidity (reduced stiffness) in the axial direction, and in the third region, the cushioning material 50 has high rigidity in the axial direction. Confirm that the buffer material 50 is plastically deformed.

If all formulas (1) to (4) are satisfied (YES in step S103), the design ends. If not satisfied (NO in step S103), the process returns to step S102 and the design of the cushioning material 50 is reviewed (the design is implemented again).

<Example of use when used in buildings>
In the above embodiment, the direction of relative displacement of the seismic isolation layer (upper structure 20 and lower structure 30) and the axial direction of the buffer material 50 were the same. Below, a specific example will be described in which the cushioning material 50 is also arranged in a direction perpendicular to the direction of relative deformation.

9A and 9B are plan views showing an example of the case where the system of this embodiment is applied to an actual building.

As shown in the figure, the upper structure 20 has a rectangular planar shape, and the retaining walls 31 of the lower structure 30 are provided so as to surround the outside of the side walls 21 on the four sides of the upper structure 20.

Further, a plurality of cushioning materials 50 are arranged between the four side walls 21 of the upper structure 20 and the retaining wall 31 of the lower structure 30, respectively. In this case, when the upper structure 20 and the lower structure 30 are relatively displaced in one horizontal direction (for example, the left-right direction in the figure), a cushioning material whose axial direction is disposed along the other horizontal direction (the vertical direction in the figure) 50 is perpendicular to the direction of relative displacement.

For this reason, in FIG. 9A, sliding plates 60 are provided on the side walls 21 around (four sides) of the upper structure 20, and are brought into contact with the axial ends (free ends) of the cushioning material 50. Thereby, even if the direction of relative displacement of the seismic isolation layer and the axial direction of the buffer material 50 are orthogonal, it is possible to follow the relative displacement of the seismic isolation layer. In this case, it is confirmed that the deformation restraint of the seismic isolation layer due to the frictional force between the sliding plate 60 and the buffer material 50 does not hinder the extension of the seismic isolation period.

Further, in FIG. 9B, a rolling member 70 such as a roller is provided at the axial end (fixed end) of the buffer material 50, so that the buffer material 50 can move along the inner surface of the retaining wall 31. In this case as well, it is possible to follow the relative displacement of the seismic isolation layer.

<Modified example>
FIG. 10A is a diagram showing a modification of the structure 1. In FIG. 10A, the same reference numerals are given to the parts having the same configuration as those of the above-described embodiment (FIG. 1), and the description thereof will be omitted. Further, FIG. 10B is a diagram showing the hysteresis characteristics of the damper 80, and FIG. 10C is a diagram illustrating the entire hysteresis characteristics in the configuration of the modified example.

In this modification, as shown in FIG. 10A, a damper 80 is provided in the gap (gap D) between the side wall 21 of the upper structure 20 and the retaining wall 31 of the lower structure 30.

The damper 80 is a damping device that generates a damping force according to the relative displacement of the upper structure 20 and the lower structure 30 in the horizontal direction. In this embodiment, an oil damper using oil is used as the damper 80. The damper 80 has, for example, a history characteristic as shown in FIG. 10B.

The history characteristics of the structure 1 of this modification are as shown in FIG. 10C, which is obtained by adding the history characteristics of FIG. 10B to the history characteristics of FIG. 3D (supporting structure 40 + cushioning material 50A + cushioning material 50B).

Also in this case, the cushioning material 50 deforms in three stages depending on the amount of displacement between the upper structure 20 and the lower structure 30 in the horizontal direction. However, since the damper 80 exerts a damping force, the deformation can be made more gradual (rapid deformation can be suppressed). Note that the damper 80 is not limited to an oil damper, and other damping members (for example, a friction damper) may be used.

===Other embodiments===
Although the embodiments of the present invention have been described above, the above-described embodiments are intended to facilitate understanding of the present invention, and are not intended to be interpreted as limiting the present invention. Further, the present invention can be modified and improved without departing from the spirit thereof, and it goes without saying that the present invention includes equivalents thereof. For example, the following modifications are possible.

In the embodiment described above, the wall portion (side wall 21) of the upper structure 20 was located inside the wall portion (retaining wall 31) of the lower structure 30, but the present invention is not limited thereto. For example, a configuration in which the upper structure 20 and the lower structure 30 are vertically inverted (a configuration in which the upper and lower structures in FIG. 1 are inverted) may be used.

Further, in the above-described embodiment, one end of the cushioning material 50 in the axial direction was fixed to the retaining wall 31 of the lower structure 30, and the other end was in contact with the side wall 21 of the upper structure 20, but this relationship is It could be the other way around. That is, one end of the cushioning material 50 in the axial direction may be in contact with the retaining wall 31 of the lower structure 30, and the other end in the axial direction may be fixed to the side wall 21 of the upper structure 20. In this case as well, the same effects as in the embodiment described above can be obtained.

In the embodiment described above, a rolling bearing was used as the bearing structure 40, but the present invention is not limited to this. For example, it may be a sliding bearing (frictional sliding bearing, etc.).

FIG. 11 is a diagram showing the history characteristics when the bearing structure 40 is a friction sliding bearing. Note that FIG. 11 shows the history characteristics up to the second region (region corresponding to FIG. 5), and the broken line shows the characteristics in the case of rolling bearing (FIG. 5C). The larger the frictional force, the larger the area surrounded by the hysteresis characteristics.

1 Structure 20 Upper structure 21, 21A, 21B Side wall (upper structure wall)
30 Lower structure 31, 21A, 31B Retaining wall (lower structure wall)
40 Support structure 50, 50A, 50B Cushioning material (intervening member)
51 Cylindrical part 51a Hollow part 60 Sliding plate 70 Rolling material 80 Damper

Claims (3)

a superstructure having a superstructure wall;
a lower structure having a lower structure wall that faces the upper structure wall at a predetermined distance in the horizontal direction;
a support structure that is provided between the upper structure and the lower structure and supports the upper structure so as to be relatively displaceable in the horizontal direction with respect to the lower structure;
an intervening member interposed between the upper structure wall and the lower structure wall, one end in the axial direction being fixed to one of the upper structure wall or the lower structure wall; an intervening member whose other end in the direction abuts the other of the upper structure wall or the lower structure wall;
A structure comprising:
In a state where the upper structure wall and the lower structure wall approach each other due to an external force, the intervening member is configured such that in a first region where the approaching displacement amount is from 0 to a first displacement amount at the time of a small earthquake or wind load. , has a predetermined rigidity in the axial direction by elastic deformation, that is, axial deformation, in the axial direction, and the approaching displacement amount in a medium earthquake or a large earthquake is smaller than the first displacement amount from the first displacement amount. In the second region up to the second displacement amount exceeded, the reduced stiffness in the axial direction is lower than the predetermined stiffness by deforming in an out-of-plane direction intersecting the axial direction, that is, by having geometric nonlinearity. and in a third region where the approaching displacement amount exceeds the second displacement amount when the design level is exceeded, the seismic energy is absorbed by plastic deformation,
The horizontal length of the intervening member is the same as the dimension of the horizontal gap between the upper structure and the lower structure in a state where the upper structure and the lower structure are not relatively displaced in the horizontal direction,
The interposed member is capable of maintaining elasticity even after deformation,
By reversing the direction of the external force, in a state where the upper structure and the lower structure are not relatively displaced in the horizontal direction, the other end in the axial direction is the other end of the upper structure wall or the lower structure wall. It has been restored to its original state while remaining in contact with the
A structure characterized by: The structure according to claim 1,
The interposed member has a hollow cylindrical part,
A structure characterized by: an upper structure having a first wall; a lower structure having a second wall facing the first wall in the horizontal direction; a support structure that supports the lower structure so as to be relatively displaceable in the horizontal direction; and an intervening member interposed between the first wall part and the second wall part, one end of which in the axial direction is connected to the first wall part. an intervening member fixed to one of the first wall or the second wall, and the other end in the axial direction abuts the other of the first wall or the second wall. A method,
determining various design conditions for the upper structure, the lower structure, and the support structure;
designing the intervening member;
In a state where the first wall portion and the second wall portion approach each other due to an external force, in a first region where the amount of approaching displacement during a small earthquake or wind load is from 0 to the first amount of displacement, the interposed member By elastically deforming, that is, axially deforming in the axial direction, a predetermined stiffness is achieved in the axial direction, and the approaching displacement amount in a medium or large earthquake exceeds the first displacement amount from the first displacement amount. In the second region up to the second displacement amount, by deforming in an out-of-plane direction intersecting the axial direction, that is, having geometric nonlinearity, the interposed member has a stiffness greater than the predetermined rigidity in the axial direction. It was confirmed that the interposed member absorbs seismic energy by plastically deforming in the third region where the approaching displacement amount exceeds the second displacement amount when the reduced stiffness is low and exceeds the design level. the step of
has
The horizontal length of the intervening member is the same as the dimension of the horizontal gap between the upper structure and the lower structure in a state where the upper structure and the lower structure are not relatively displaced in the horizontal direction,
The interposed member is capable of maintaining elasticity even after deformation,
By reversing the direction of the external force, in a state where the upper structure and the lower structure are not relatively displaced in the horizontal direction, the other end in the axial direction is the other of the first wall portion or the second wall portion. It has been restored to its original state while remaining in contact with the
A method of designing a structure characterized by the following.

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