JP2005248520A - Base isolation damper, base isolation structure and base isolation method of structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate control, by easily removing residual deformation after deforming a base isolation layer, and preventing generation of a large operation sound when deforming the base isolation layer of a base isolation structure by a strong wind. <P>SOLUTION: This damper 3 has a piston 7 sliding in a case 6, and the case 6 has an inner cylinder 10 and an outer cylinder 20 sealed with fluid, and a storage chamber 13 is arranged in a part of the outer cylinder 10. The inside of the inner cylinder 10 is partitioned into a first chamber 11 and a second chamber 12 for passing a rod 8. A check valve 100 for allowing only a fluid flow to the first chamber 11 from the second chamber 12, is arranged in a flow passage 7A for communicating the first chamber 11 with the second chamber 12. A first flow passage 10A for communicating the first chamber 11 with the storage chamber 13, a second flow passage 10B for communicating the second chamber 12 with the storage chamber 13, and an orifice 10D for communicating the first chamber 11 with the storage chamber 13 in parallel to the first flow passage 10A are formed. A relief valve 101 for making fluid in the first chamber 11 flow to the storage camber 13 when fluid pressure in the first chamber 11 becomes a predetermined value or more, is arranged in the first flow passage 10A. A suction valve 102 for allowing only the fluid flow to the second chamber 12 from the storage chamber 13, is arranged in the second flow passage 10B. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a seismic isolation damper, a seismic isolation structure, and a seismic isolation method for a structure.

  Conventionally, seismic isolation buildings have a base isolation such as laminated rubber that supports vertical loads and has low horizontal rigidity, and oil dampers, elasto-plastic dampers, friction dampers, etc. that absorb energy input to the buildings. A seismic isolation layer including a seismic damper is used (see, for example, Patent Document 1). According to such a configuration, when the seismic isolation building receives a large earthquake such as an earthquake, the seismic isolation support lengthens the building cycle to reduce the seismic isolation building vibration and the seismic isolation damper is exempted. The vibration of the seismic building is attenuated to suppress the seismic motion of the base-isolated building.

By the way, in addition to the above-mentioned seismic isolation layer, in addition to the above-mentioned seismic isolation layer, there are wind-resistant triggers for seismic isolation buildings in areas that are susceptible to wind such as along the coast and typhoon passage areas. The friction damper which becomes is used together. According to such a base-isolated building, when the wind is less than a certain load, the friction damper and the base isolation layer are not deformed by the frictional force of the friction material (brake material) of the friction damper. In the event of strong winds or strong vibrations such as earthquakes, the friction damper slides and the seismic isolation bearings and seismic isolation dampers act to suppress the vibration of the building as described above.
JP 2002-266936 A

However, when a friction damper is used as a wind-resistant trigger, a large sliding noise is generated when the friction damper is acted upon by strong vibrations such as strong winds. Therefore, it is necessary to take measures against the sliding noise. In addition, it is conceivable to reduce the hardness of the friction material in order to suppress the sliding noise. In this case, however, the wear resistance of the friction material is likely to decrease, and this reduces the cumulative number of sliding distances of the friction damper. There is a problem that it is necessary to replace the friction damper before it is or is not so large, and the management of the friction damper is complicated and the maintenance cost increases.
Further, after the friction damper slides due to strong vibration such as strong wind, the friction damper may stop at a position shifted from the neutral position (initial position). In this case, since deformation remains in the seismic isolation layer in addition to the friction damper, it is necessary to remove the residual deformation, etc., and the management of the friction damper and the seismic isolation layer is complicated, resulting in an increase in maintenance costs. There is also.

  The object of the present invention is to prevent the generation of loud operating noise when the structure vibrates due to strong winds, etc., and the residual deformation of the seismic isolation layer after the vibration is eliminated over time, making it easy to manage. The object is to provide seismic dampers, seismic isolation structures, and seismic isolation methods for structures.

  The seismic isolation damper of the present invention includes a cylinder in which a fluid is sealed, a case including a storage chamber communicating with the cylinder, and a piston that is slidably disposed in the cylinder and to which a rod is connected, The cylinder is partitioned by the piston into a first chamber on the side through which the rod is passed and a second chamber on the opposite side, and the piston communicates with the first chamber and the second chamber. An indoor flow path is formed, and the cylinder has a first flow path communicating the first chamber and the storage chamber, and a second flow path communicating the second chamber and the storage chamber, A first check valve that allows the fluid to flow only in a direction from the second chamber toward the first chamber is disposed in the indoor flow path, and the first flow path includes the first check valve in the first chamber. When the fluid pressure exceeds a predetermined value, the fluid in the first chamber A relief valve that circulates to the storage chamber is disposed, and a second check valve that allows the fluid to flow only in a direction from the storage chamber toward the second chamber is disposed in the second flow path, The cylinder is characterized in that an orifice that communicates the first chamber and the storage chamber is formed in parallel with the first flow path.

  Here, as the fluid, silicon oil or a liquid such as oil or water, a gas such as air, a magnetic fluid, or other fluid can be employed. The inner diameter of the orifice is preferably as small as 0.5 mm or less, for example. The shape of the orifice is not particularly limited. The seismic isolation damper may include an opening / closing mechanism for opening / closing the orifice.

In the seismic isolation damper of the present invention, when a load in the direction of extending the piston is applied, the first chamber is compressed, and the flow of fluid from the second chamber to the first chamber is caused by the first check valve. Be blocked. At this time, an orifice is formed between the first chamber and the storage chamber, but since the flow path area is small, the flow of fluid does not substantially occur. For this reason, the fluid pressure in the first chamber rises, and a substantially constant damping load corresponding to the valve opening pressure of the relief valve is generated by this fluid pressure.
Further, when a load in the direction of contracting the piston is applied, the rod enters the cylinder and the cylinder volume is reduced, thereby compressing the first chamber and the second chamber. At that time, as described above, since the flow path area is small, a fluid flow does not substantially occur in the orifice. For this reason, the fluid pressure in the first chamber and the second chamber rises, and a substantially constant damping load corresponding to the valve opening pressure of the relief valve is generated by this fluid pressure.
As described above, since a substantially constant damping load corresponding to the valve opening pressure of the relief valve can be generated regardless of the sliding speed of the piston, the displacement of the structure due to strong wind or the like can be suppressed. In addition, since the damping load is generated by the action of the fluid, there is no generation of sliding noise like a friction damper, the operation noise can be suppressed to a small level, and no wear is generated, so that maintenance work can be reduced.

  Further, in the seismic isolation damper according to the present invention, when residual deformation occurs in a state where the first chamber is compressed (a state where the piston is extended), a load in the contraction direction acts on the piston. When the piston is displaced in the contracting direction, the volume in the cylinder is reduced by the amount of the rod entering the cylinder. By flowing into the storage chamber, the piston can slide gradually in the contraction direction. As a result, the seismic isolation damper returns to the neutral position. Further, when residual deformation occurs in a state where the second chamber is compressed (a state where the piston contracts), a load in the extending direction acts on the piston. When the piston is displaced in the extending direction, the fluid flows into the second chamber from the storage chamber through the second check valve, and the pressure increases from the first chamber through the orifice to the storage chamber over time. The fluid flows out and the piston can slide gradually in the extending direction. As a result, the seismic isolation damper returns to the neutral position. Since the piston returns to the neutral position by such a fluid flow, the residual deformation can be easily eliminated.

  The present invention is a seismic isolation structure comprising a base isolation bearing that supports a structure and a base isolation damper that attenuates the vibration of the structure, and a part of the base isolation damper is the base isolation damper It is characterized by that. Moreover, the seismic isolation method for a structure according to the present invention is characterized in that the structure is supported by a seismic isolation support, and the vibration of the structure is attenuated by a plurality of seismic isolation dampers including the seismic isolation damper.

  According to the present invention, it is possible to prevent the generation of a large operating sound when a structure vibrates due to strong winds, etc., and the residual deformation of the seismic isolation layer after the vibration is eliminated over time, so that the seismic isolation layer can be managed. There is an effect that it can be easily done.

Hereinafter, a seismic isolation structure example according to an embodiment of the oil damper of the present invention will be described.
FIG. 1 is a front view showing a seismic isolation structure 1 according to the present embodiment. FIG. 2 is a plan view showing the seismic isolation structure 1. As shown in FIG. 1, the seismic isolation structure 1 is comprised between the recessed part G1 formed in the ground G, and the building 2 as a structure. As shown in FIG. 2, the seismic isolation structure 1 includes a wind-resistant trigger oil damper 3 as a seismic isolation damper according to the present invention, an oil damper 4 as a seismic isolation damper that attenuates the vibration of the building 2, and a long building cycle. It is provided with a laminated rubber 5 as a seismic isolation bearing that periodically transmits to the building 2 and reduces the vibration of the building 2.
In the present embodiment, as shown in FIG. 2, the wind-resistant trigger oil damper 3 is arranged in parallel with the direction (from right to left in FIG. 2) where strong wind is expected to blow.

First, the oil damper 4 will be described.
3 and 4 are schematic views showing the oil damper 4. As shown in FIGS. 3 and 4, the oil damper 4 includes a case 6 and a piston 7 configured to be slidable in the case 6. A rod 8 protruding from one end of the case 6 (left end in FIGS. 2 and 3) is connected to the piston 7. An attachment portion 8A provided at the tip of the rod 8 is fixed to the lower part of the building 2, and an attachment portion 6A provided at the other end of the case 6 is fixed to the recess G1 of the ground G.

As shown in FIGS. 3 and 4, the case 6 includes an inner cylinder 10 as a cylinder in which oil is sealed, and an outer cylinder 20 disposed on the outer periphery of the inner cylinder 10. The inside of the inner cylinder 10 is partitioned by the piston 7 into a first chamber 11 on the side (left side in the drawing) through which the rod 8 is passed and a second chamber 12 on the opposite side.
The piston 7 is formed with an indoor flow path 7 </ b> A that communicates the first chamber 11 and the second chamber 12. A check valve 100 is provided in the indoor flow path 7A. As shown in FIG. 4, the check valve 100 opens the indoor flow path 7 </ b> A when the piston 7 slides in the contraction direction (the direction in which the second chamber 12 contracts; the right direction in the drawing). When the piston 7 slides in the extending direction (the direction in which the second chamber 12 is expanded; the left direction in the figure) as shown in FIG. The flow of oil between the first chamber 11 and the second chamber 12 is blocked by closing the flow path 7A. This check valve 100 corresponds to a first check valve of the present invention.

  An outer cylinder chamber 13 </ b> A is formed between the inner cylinder 10 and the outer cylinder 20. A spare chamber 13B communicates with the outer cylinder chamber 13A. The outer cylinder chamber 13A is filled with oil, and the reserve chamber 13B retains oil while leaving a predetermined space. The outer cylinder chamber 13A and the spare chamber 13B correspond to the storage chamber 13 of the present invention. The inner cylinder 10 has a first flow path 10A that communicates the first chamber 11 and the outer cylinder chamber 13A, a second flow path 10B that communicates the second chamber 12 and the outer cylinder chamber 13A, and a first flow path. In parallel with 10A, a third flow path 10C communicating with the first chamber 11 and the outer cylinder chamber 13A is formed.

The first channel 10A is normally closed when the first channel 10A is closed and the oil pressure in the first chamber 11 is higher than the oil pressure in the storage chamber 13 by a predetermined pressure or more. Is opened, and a relief valve 101 is attached to flow the oil in the first chamber 11 to the outer cylinder chamber 13A.
When the piston 7 slides in the extending direction as shown in FIG. 3, the second flow path 10B is opened in the second flow path 10B so that oil flows from the outer cylinder chamber 13A to the second chamber 12. Further, as shown in FIG. 4, when the piston 7 slides in the contraction direction, the second flow path 10B is closed to prevent the oil from flowing between the outer cylinder chamber 13A and the second chamber 12. A suction valve 102 as a second check valve is attached.
A pressure regulating valve 103 that generates a damping force by adjusting the opening / closing state of the third flow path 10C according to the sliding speed of the piston 7 is attached to the third flow path 10C.

FIG. 5 is a diagram showing the relationship between the sliding speed of the piston 7 in the oil damper 4 and the load applied to the relief valve 101 and the pressure regulating valve 103.
In the oil damper 4, when the piston 7 slides in the extending direction at a slow speed equal to or less than the speed Xs, the first chamber 11 is contracted and the oil flow from the second chamber 12 to the first chamber 11 is checked. Blocked by 100. At this time, since the oil pressure in the first chamber 11 is equal to or lower than the valve opening pressure of the relief valve 101, a damping load corresponding to the sliding speed of the piston 7 is generated by the pressure regulating valve 103 (pressure regulating valve region shown in FIG. 5). . When the sliding speed of the piston 7 exceeds Xs, the oil pressure in the first chamber 11 becomes equal to or higher than the valve opening pressure of the relief valve 101, and the relief valve 101 is opened, and according to the valve opening pressure of the relief valve 101. A substantially constant damping load is generated (relief valve region shown in FIG. 5).

  Further, when the piston 7 slides in the contraction direction at a slow speed equal to or less than the speed Xs, the rod 8 enters the inner cylinder 10 and the volume of the inner cylinder 10 is reduced, whereby the first chamber 11 and the second chamber are reduced. 12 is shrunk as a whole. At this time, since the oil pressure in the first chamber 11 and the second chamber 12 is equal to or lower than the valve opening pressure of the relief valve 101, a damping load corresponding to the sliding speed of the piston 7 is generated by the pressure regulating valve 103 (FIG. 5). Pressure regulating valve area). When the sliding speed of the piston 7 exceeds Xs, the oil pressure in the first chamber 11 and the second chamber 12 becomes equal to or higher than the valve opening pressure of the relief valve 101, and the relief valve 101 is opened. A substantially constant damping load corresponding to the valve opening pressure is generated (the relief valve region shown in FIG. 5). As described above, the relationship between the sliding speed of the piston 7 in the oil damper 4 and the load applied to the relief valve 101 and the pressure regulating valve 103 has a damping characteristic proportional to the sliding speed when the sliding speed of the piston 7 is Xs or less. The pressure regulation valve area | region shown and the relief valve area | region which shows the damping characteristic of substantially constant damping load Fr without depending on speed | velocity, when the sliding speed of piston 7 exceeds Xs will be included.

Next, the windproof trigger oil damper 3 will be described.
6 and 7 are schematic views showing the wind-resistant trigger oil damper 3. As shown in FIGS. 6 and 7, the wind-resistant trigger oil damper 3 has a configuration in which an orifice 10 </ b> D is provided in the oil damper 4 instead of the pressure regulating valve 103 and the third flow path 10 </ b> C.
The orifice 10D is provided in parallel with the first flow path 10A so as to communicate the first chamber 11 and the outer cylinder chamber 13A. The inner diameter of the orifice 10D is, for example, about 0.5 mm or less.

FIG. 8 is a diagram showing the relationship between the sliding speed of the piston 7 in the wind-resistant trigger oil damper 3 and the load applied to the relief valve 101 and the orifice 10D.
In the wind-resistant trigger oil damper 3, when the piston 7 slides in the extending direction at a slow speed of the speed Xr or less, the first chamber 11 is contracted, the oil pressure in the first chamber 11 is increased, and the load suddenly rises. (Orifice region shown in FIG. 8). When the sliding speed of the piston 7 exceeds Xr and the oil pressure in the first chamber 11 reaches the valve opening pressure of the relief valve 101, the relief valve 101 is opened and oil flows into the first flow path 10A. Thus, a substantially constant damping load corresponding to the opening valve of the relief valve 101 is generated (relief valve region shown in FIG. 8).

  Further, when the piston 7 slides in the contraction direction at a slow speed equal to or less than the speed Xr, the first chamber 11 and the second chamber 12 are contracted as a whole, and the oil pressure in the first chamber 11 and the second chamber 12 increases. Thus, the damping load rises rapidly (orifice region shown in FIG. 8). When the sliding speed of the piston 7 exceeds Xr and the oil pressure in the first chamber 11 and the second chamber 12 reaches the valve opening pressure of the relief valve 101, the relief valve 101 is opened and the first flow path 10A. As a result of the oil flowing into the valve, a substantially constant damping load corresponding to the opening valve of the relief valve 101 is generated (relief valve region shown in FIG. 8).

As described above, the relationship between the sliding speed of the piston 7 in the wind-resistant trigger oil damper 3 and the load applied to the relief valve 101 and the orifice 10D has a load characteristic that increases rapidly when the sliding speed of the piston 7 is Xr or less. And the relief valve region showing a substantially constant damping load Fr without depending on the sliding speed when the sliding speed of the piston 7 exceeds Xr.
In addition, since the amount of oil to be compressed differs depending on the sliding direction of the piston 7 as described above, the load characteristic also differs depending on the sliding direction of the piston 7.

Here, in the wind resistant trigger oil damper 3, when residual deformation occurs in a state where the first chamber 11 is compressed, that is, when the piston 7 is displaced from the neutral position in the extending direction, a load in the contraction direction is applied to the piston 7. Works. When the piston 7 is displaced in the contraction direction, the volume in the inner cylinder 10 is reduced by the amount that the rod 8 enters the inner cylinder 10, but the oil corresponding to the volume reduction is supplied to the first chamber 11 and the second chamber 12. The piston 7 can be gradually slid in the contraction direction by flowing to the outer cylinder chamber 13A over time through the orifice 10D. Thereby, the wind-resistant trigger oil damper 3 returns to the neutral position.
Further, when residual deformation occurs in a state where the second chamber 12 is compressed, that is, when the piston 7 is displaced from the neutral position in the contraction direction, a load in the extension direction acts on the piston 7. When the piston 7 is displaced in the extending direction, oil flows into the second chamber 12 from the outer cylinder chamber 13A through the suction valve 102, and it takes time from the first chamber 11 where the pressure has increased through the orifice 10D. Then, oil flows out to the outer cylinder chamber 13A, and the piston 7 can slide gradually in the extending direction. Thereby, the wind-resistant trigger oil damper 3 returns to the neutral position. Since the piston 7 returns to the neutral position due to such oil flow, residual deformation can be easily eliminated.

  In such a wind-resistant trigger oil damper 3, the load applied to the piston 7 has a load deformation relationship as shown in FIG. As shown in this load-deformation relationship, the damping force rises with a gradient by compressing the oil (orifice region), so the load until entering the relief valve region by that gradient compared to when using a friction damper. Changes gradually, and the response acceleration of the building 2 due to an earthquake or the like can be reduced.

The seismic isolation structure 1 having such a configuration operates as follows.
As shown in FIGS. 1 and 2, when a relatively weak wind or the like acts, the wind-resistant trigger oil damper 3 hardly slides, thereby suppressing the seismic isolation layer deformation of the building 2. Further, when strong wind or the like exceeding the windproof trigger level acts on the building 2, the windproof trigger oil damper 3 and the rod 8 of the oil damper 4 slide, and the laminated rubber 5 is deformed in the horizontal direction. At this time, the above-described damping load acts on the wind-resistant trigger oil damper 3 and the oil damper 4, and the deformation of the seismic isolation layer of the building 2 is attenuated and converged. In addition, after the seismic isolation layer slides, residual deformation may occur in the wind-resistant trigger oil damper 3, the oil damper 4, and the laminated rubber 5, respectively. In this case, since the oil flows through the orifice 10D in the wind resistant trigger oil damper 3 due to the force of the laminated rubber 5 to return to the neutral position, the residual deformation of the wind resistant trigger oil damper 3 is eliminated over time, The residual deformation of the oil damper 4 and the laminated rubber 5 is also eliminated. For this reason, the seismic isolation structure 1 will return to the original state.

According to this embodiment, there are the following effects.
(1) Even when residual deformation occurs in the wind resistant trigger oil damper 3 due to the influence of strong winds, etc., the oil flows through the orifice 10D, so that the wind resistant trigger oil damper 3, the oil damper 4, and the laminated rubber 5 Residual deformation can be resolved automatically and is convenient.
(2) Even if the wind-resistant trigger oil damper 3 is acted on by strong wind or the like, it is possible to prevent the generation of a large operating noise such as a friction damper because the sound that is applied to the oil movement is generated.
(3) Since there is no wear or the like unlike the friction damper, maintenance work for the wind-resistant trigger oil damper 3 can be reduced.
(4) Since a damping force due to oil contraction in the orifice region is generated, the response acceleration of the building 2 at the time of an earthquake or the like can be reduced as compared with the friction damper, and the comfortability of the building 2 can be improved.

In addition, this invention is not limited to the said embodiment, Including other structures etc. which can achieve the objective of this invention, the modification etc. which are shown below are also contained in this invention.
For example, FIG. 10 is a view in which the orifice on / off valve 210 is opened in the windproof trigger oil damper 200 according to the modification of the present invention. FIG. 11 is a view in which the orifice on / off valve 210 is closed in the wind-resistant trigger oil damper 200 according to the modification of the present invention. As shown in FIGS. 10 and 11, the wind-resistant trigger oil damper 200 includes an orifice opening / closing valve 210 as an opening / closing mechanism attached to the outer cylinder 20 and opening / closing the orifice 10D in the wind-resistant trigger oil damper 3 of the above-described embodiment. Configured. By providing such an orifice opening / closing valve 210, for example, as shown in FIG. 11, the orifice 10D is closed with the orifice opening / closing valve 210 closed in a normal state, and the building 2 is vibrated or deformed by strong wind or earthquake motion. When residual deformation occurs in the seismic isolation structure 1, the residual deformation can be appropriately eliminated by opening the orifice on-off valve 210 as shown in FIG.
In addition, the shape, length dimension, quantity, etc. of the orifice 10D are not particularly limited as long as it is a minute opening, and the inner diameter of the orifice 10D does not need to be as small as 0.5 mm or less. It may be about 3 mm.

In the said embodiment, the installation condition of the wind-resistant trigger oil damper 3, the oil damper 4, and the laminated rubber 5 is not limited to arrangement | positioning and quantity as shown in FIG. 1, FIG.
Moreover, in the said embodiment, although the oil damper 4 was employ | adopted for the seismic isolation structure 1, you may employ | adopt other seismic isolation dampers, such as not only this but an elastic-plastic damper and a friction damper. Further, seismic isolation bearings other than the laminated rubber 5 may be adopted.
Moreover, in the said embodiment, although the seismic isolation structure 1 was arrange | positioned between the ground G and the building 2, it is not restricted to this, For example, between the 2nd floor and the 3rd floor, ie, a lower structure and an upper structure You may arrange | position between. In short, it is not always necessary to install the seismic isolation structure 1 on the ground G.
In the above embodiment, oil is used as the fluid. However, silicon oil, other liquids such as water, gas such as air, magnetic fluid, and the like may be used.

It is a front view which shows the seismic isolation structure which concerns on one Embodiment of this invention. It is a top view which shows the said seismic isolation structure. It is a schematic diagram (the 1) which shows the oil damper which comprises the said seismic isolation structure. It is a schematic diagram (the 2) which shows the oil damper which comprises the said seismic isolation structure. It is a figure which shows the relationship between the sliding speed of the piston in the said oil damper, and the load concerning a relief valve and a pressure regulation valve. It is a schematic diagram (the 1) which shows the wind-resistant trigger oil damper which comprises the said seismic isolation structure. It is a schematic diagram (the 2) which shows the wind-proof trigger oil damper which comprises the said seismic isolation structure. It is a figure which shows the relationship between the sliding speed of the piston in the said wind-resistant trigger oil damper, and the load concerning a relief valve and an orifice. It is a figure which shows a load deformation relationship in the said wind-resistant trigger oil damper. In the wind-resistant trigger oil damper which concerns on the modification of this invention, it is the figure which made the orifice on-off valve open state. In the wind-resistant trigger oil damper which concerns on the modification of this invention, it is the figure which made the orifice on-off valve the closed state.

Explanation of symbols

1 Seismic isolation structure 2 Building (structure)
3 Windproof trigger oil damper (Seismic isolation damper according to the present invention)
4 Oil damper 5 Laminated rubber (Seismic isolation bearing)
6 Case 7 Piston 7A Indoor flow path 8 Rod 10 Inner cylinder 10A First flow path 10B Second flow path 10D Orifice 11 First chamber 12 Second chamber 13 Storage chamber 13A Outer cylinder chamber 13B Preliminary chamber 20 Outer cylinder 100 Check valve ( First check valve)
101 Relief valve 102 Suction valve (second check valve)

Claims (4)

A cylinder including a fluid, a case including a storage chamber communicating with the cylinder, and a piston slidably disposed in the cylinder and connected to a rod;
The inside of the cylinder is partitioned by the piston into a first chamber on the side through which the rod is passed and a second chamber on the opposite side.
The piston is formed with an indoor flow path communicating with the first chamber and the second chamber,
The cylinder is formed with a first flow path communicating the first chamber and the storage chamber, and a second flow path communicating the second chamber and the storage chamber,
A first check valve that allows the fluid to flow only in the direction from the second chamber toward the first chamber is disposed in the indoor flow path,
In the first flow path, when a fluid pressure in the first chamber becomes a predetermined value or more, a relief valve that distributes the fluid in the first chamber to the storage chamber is disposed,
A second check valve that allows the fluid to flow only in the direction from the storage chamber to the second chamber is disposed in the second flow path,
The seismic isolation damper according to claim 1, wherein an orifice that communicates the first chamber and the storage chamber is formed in parallel with the first flow path.   The seismic isolation damper according to claim 1, further comprising an opening / closing mechanism for opening / closing the orifice. A base-isolated structure comprising a base-isolated bearing that supports the structure and a plurality of base-isolated dampers that attenuate the vibration of the structure,
A part of said some seismic isolation damper is the seismic isolation damper of Claim 1 or 2, The base isolation structure characterized by the above-mentioned. A structure seismic isolation method, wherein a structure is supported by a seismic isolation bearing, and vibrations of the structure are attenuated by a plurality of seismic isolation dampers including the seismic isolation damper according to claim 1.

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