JP2016216906A - Base isolation structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base isolation structure capable of reducing a construction cost of a building while keeping high base isolation performance.SOLUTION: A base isolation structure comprises: a first base isolation layer 14 which supports a first structure body 11; a second base isolation layer 16 which is constructed on the first structure body 11 and supports a second structure body 12; and a trigger member 20 which is installed on the second base isolation layer 16 and slides or deforms when earthquake force not less than a predetermined magnitude is input in a manner that displaces the second structure body 12 relative to the first structure body 11 in a horizontal direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a seismic isolation structure.

  Patent Document 1 discloses a base-isolated structure building having a plurality of base isolation layers in which each of a plurality of building blocks (structures) is supported by laminated rubber and stacked in the building height direction. Patent Document 2 discloses a base-isolated structure in which each of a plurality of structures is laminated in the building height direction via a base isolation layer. A technique is disclosed in which an oil damper is disposed in the seismic layer to adjust the magnitude of attenuation applied to the upper seismic isolation layer.

Japanese Patent Laid-Open No. 1-263373 JP 2014-80794 A

  In the techniques disclosed in Patent Document 1 and Patent Document 2, by providing a plurality of base isolation layers in the height direction of the building, the deformation of the base isolation building that occurs during an earthquake is dispersed, and the horizontal displacement of the lower base isolation layer The amount can be reduced. For this reason, the structure of a lower base isolation layer becomes easy compared with the building which is not provided with the several base isolation layer in the height direction of the building. On the other hand, since a horizontal displacement occurs in the upper isolation layer regardless of the magnitude of the earthquake, shear deformation occurs in an elevator shaft, piping, and the like that penetrates the isolation layer in the vertical direction. For this reason, a follow-up mechanism that absorbs shear deformation such as an elevator shaft and piping is required during an earthquake, and there is room for improvement from the viewpoint of reducing the construction cost of the building.

  In view of the above facts, an object of the present invention is to provide a seismic isolation structure capable of reducing the construction cost of a building while having high seismic isolation performance.

  The base isolation structure according to claim 1 is a first base isolation layer that supports a first structure, a second base isolation layer that is provided on the first structure and supports a second structure, and A trigger member which is provided in the second seismic isolation layer and slides or deforms when a seismic force of a predetermined value or more is input, and relatively displaces the second structure in the horizontal direction with respect to the first structure; Have.

  According to the seismic isolation structure according to claim 1, the first structure is supported by the first seismic isolation layer, and the second structure is supported by the second seismic isolation layer on the first structure. Has been. Here, a trigger member is provided in the second seismic isolation layer. The trigger member does not slide or deform until a seismic force of a predetermined value or more is input, and the second structure is not displaced relative to the first structure. That is, when the seismic force is equal to or less than a predetermined value, the first structure and the second structure are displaced in the horizontal direction integrally. This alleviates the need to design a follow-up mechanism that absorbs shear deformations such as elevator shafts and piping.

  On the other hand, when a seismic force of a predetermined value or more is input to the second seismic isolation layer, the trigger member slides or deforms, so that the second structure is relatively displaced in the horizontal direction with respect to the first structure. Thereby, compared with the structure which is not provided with the 2nd seismic isolation layer (the seismic isolation layer in the upper part among a plurality of seismic isolation layers), the amount of horizontal displacement of the 1st structure can be made small.

  Furthermore, the second seismic isolation layer does not function until a seismic force greater than the specified value is input, so compared to the base isolation structure with multiple seismic isolation layers in the building height direction without trigger members, The horizontal deformation amount of the second seismic isolation layer after the seismic force of a predetermined value or more is input can be reduced. Further, the response acceleration of the second structure can be reduced accordingly.

  A seismic isolation structure according to a second aspect of the present invention is the seismic isolation structure according to the first aspect, wherein the trigger member is a sliding bearing or a steel damper.

  According to the seismic isolation structure according to the second aspect of the present invention, when the sliding bearing is used as the trigger member, the static frictional force of the sliding bearing becomes the trigger load. Then, when the seismic force greater than the static friction force is input, the trigger is released and a slip accompanied by a dynamic friction force occurs. As a result, it is possible to absorb input energy due to earthquake motion. On the other hand, when a steel damper is used as a trigger member, the yield load of the steel damper becomes the trigger load. When a seismic force greater than the yield load is input, the trigger is released and the steel damper is plastically deformed. As a result, it is possible to absorb the input energy due to the earthquake motion.

  The seismic isolation structure according to the present invention as set forth in claim 3 is the seismic isolation structure according to claim 1 or 2, wherein the trigger member is an external force due to an earthquake motion in which the second seismic isolation layer is generated very rarely. When receiving, it slides or deforms, and the second structure is relatively displaced in the horizontal direction with respect to the first structure.

  According to the seismic isolation structure according to the third aspect of the present invention, the lower structure and the upper structure are integrally displaced horizontally except in the case of receiving an external force due to an extremely rare earthquake motion (large earthquake). To do. That is, in the case of earthquakes that occur relatively frequently, the lower structure and the upper structure are horizontally displaced integrally, so that it is not necessary to consider the shear stress acting on the elevator shaft and piping. Thereby, the same equipment structure as a base-isolated building which does not have a plurality of base-isolated layers in the building height direction can be applied, and the construction cost can be effectively reduced. The term “earthquake that occurs extremely rarely” here refers to the earthquake motion announced in the Ministry of Land, Infrastructure, Transport and Tourism Notification No. 388 on March 30, 2003. This refers to an earthquake motion having an acceleration response spectrum that is five times as large as the acceleration response spectrum for “seismic motion”.

  As described above, according to the seismic isolation structure of the present invention, it is possible to reduce the construction cost of a building while providing high seismic isolation performance.

It is an elevation view showing a building to which the seismic isolation structure according to the embodiment is applied. It is a schematic diagram which shows roughly the vibration model of the building of FIG. It is the graph which compared the seismic isolation performance of the seismic isolation structure which concerns on embodiment, and the seismic isolation performance of the base isolation structure of a comparative example, (A) shows the relationship between the magnification of an earthquake input, and the acceleration of a 2nd structure. It is a graph, (B) is a graph which shows the relationship between the magnification of an earthquake input, and the horizontal deformation amount of a 2nd seismic isolation layer. (A) is an elevation view showing a building to which the base isolation structure of Comparative Example 1 is applied, and (B) is an elevation view showing a building to which the base isolation structure of Comparative Example 2 is applied. (A) is the enlarged view which expanded the 2nd seismic isolation layer of the building of the 1st modification of the seismic isolation structure which concerns on embodiment, (B) is the building of the 2nd modification of the seismic isolation structure which concerns on embodiment It is the enlarged view to which the 2nd seismic isolation layer of was expanded. (A) is an elevation view showing a building of a third modification of the seismic isolation structure according to the embodiment, and (B) is an elevation view showing a building of the fourth modification of the seismic isolation structure according to the embodiment. is there. It is an elevation view which shows the building of the 5th modification of the seismic isolation structure which concerns on embodiment. It is an elevation view which shows the building of the 6th modification of the seismic isolation structure which concerns on embodiment.

  Hereinafter, a seismic isolation structure according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a building 10 to which the seismic isolation structure according to the present invention is applied includes a lower first structure 11 and an upper second structure 12. A first seismic isolation layer 14 is provided below the first structure 11, and the first structure 11 is supported by the first seismic isolation layer 14.

  On the other hand, the second structure 12 is stacked on the first structure 11. A second seismic isolation layer 16 is provided between the first structure 11 and the second structure 12, and the second structure 12 is supported by the second seismic isolation layer 16. In the present embodiment, the first structure 11 and the second structure 12 are structures having substantially the same size. However, the present invention is not limited to this, and the first structure 11 and the second structure 12 May be formed in different sizes.

  The first seismic isolation layer 14 includes a laminated rubber 18 that is a seismic isolation support member, and a seismic isolation damping member (for example, an oil damper) (not shown). The seismic isolation damping member connects the foundation 100 and the first structure 11, and imparts damping to the first seismic isolation layer 14.

  The laminated rubber 18 includes a lower flange 18A, an upper flange 18B, and a main body portion 18C provided between the lower flange 18A and the upper flange 18B. The lower flange 18A is fixed to the base 100 by a bolt or the like (not shown), and the upper flange 18B is fixed to the lower surface side of the first structure 11 by a bolt or the like (not shown). The main body portion 18C is formed by laminating a rubber plate and a steel plate in the vertical direction, and is configured to be deformable in the horizontal direction.

  In addition, as long as it can support the 1st structure 11 so that relative displacement is possible in a horizontal direction, you may use not only the laminated rubber 18 but another seismic isolation bearing member. In FIG. 1, three laminated rubbers 18 are illustrated, but the number and size of the laminated rubbers 18 are not particularly limited.

  The second seismic isolation layer 16 is configured to include a sliding bearing 20 as a trigger member. In the present embodiment, a rigid sliding bearing is used as an example of the sliding bearing 20. Moreover, you may arrange | position the laminated rubber which is not illustrated in the 2nd seismic isolation layer 16 as needed.

  The sliding bearing 20 includes a bearing part 20A and a slide plate 20B. 20 A of support parts are formed in the substantially cylindrical shape from which a lower surface side turns into a sliding surface. Further, the support portion 20A is fixed to the lower surface of the second structure 12 by a bolt (not shown) or the like, and is configured to be horizontally displaced integrally with the second structure 12. On the other hand, the slide plate 20 </ b> B is disposed between the support portion 20 </ b> A and the first structure 11, and is fixed to the upper surface of the first structure 11. The laminated rubber provided in the second seismic isolation layer 16 has the same configuration as the laminated rubber 18 provided in the first seismic isolation layer 14. Note that the relative positional relationship between the support portion 20A and the slide plate 20B may be reversed.

  The vibration model of the base-isolated structure configured as described above is expressed as shown in FIG. Here, reference numeral 22 indicates the basis of the first structure 11, and reference numeral 24 indicates the basis of the second structure 12.

  The spring constant k1 and the damping coefficient c1 indicate the vibration characteristics of the first seismic isolation layer 14, and are determined by the laminated rubber 18 and a seismic isolation damping member (oil damper or the like) not shown. The spring constant k2 and the damping coefficient c2 indicate the vibration characteristics of the first structure 11 and are determined by the structure of the first structure 11 and the like.

  On the other hand, the spring constant k3 and the damping coefficient c3 indicate the vibration characteristics of the second seismic isolation layer 16, and are determined by the sliding bearing 20 and a laminated rubber (not shown). Furthermore, the spring constant k4 and the damping coefficient c4 indicate the vibration characteristics of the second structure 12 and are determined by the structure of the second structure 12 and the like.

  Here, a trigger load is set for the second seismic isolation layer 16. As for this trigger load, the second seismic isolation layer 16 does not function when a seismic force smaller than a predetermined value is input, and the second seismic isolation layer 16 functions when a seismic force greater than the predetermined value is input. It is configured as follows. In the present embodiment, the static frictional force of the sliding bearing 20 is a trigger load. That is, when an external force greater than the static friction force is input to the slide bearing 20 by an earthquake force greater than a predetermined value, the trigger is released and the bearing portion 20A slides on the slide plate 20B. As a result, the second structure 12 is displaced relative to the first structure 11 in the horizontal direction. Moreover, at this time, it is comprised so that the input energy by a seismic motion can be absorbed because dynamic friction force arises.

  In the present embodiment, as an example, the bearing portion 20A is configured to slide on the slide plate 20B when receiving an external force due to an extremely rare earthquake motion. The “earthquake that occurs extremely rarely” here refers to the earthquake motion announced in the Ministry of Land, Infrastructure, Transport and Tourism Notification No. 388 on March 30, 2003. ”Refers to a ground motion having an acceleration response spectrum that is five times the acceleration response spectrum.

(Function and effect)
Next, the operation and effect of the seismic isolation structure of this embodiment will be described. In this embodiment, the sliding bearing 20 is provided in the 2nd seismic isolation layer 16, and it is comprised so that the sliding bearing 20 may not function until the seismic force beyond a predetermined value is input. As a result, during earthquakes that occur relatively frequently, the laminated rubber 18 of the first seismic isolation layer 14 is deformed and the first structure 11 is displaced in the horizontal direction, whereas the second seismic isolation layer 16 is displaced. Does not function, and the bearing portion 20A of the sliding bearing 20 does not slide on the slide plate 20B. For this reason, the second structure 12 is not displaced relative to the first structure 11, and the first structure 11 and the second structure 12 are integrally displaced in the horizontal direction. As a result, even when the elevator shaft and piping are arranged through the first structure 11 and the second structure 12, it is not necessary to consider the shear stress acting on the elevator shaft and piping. That is, the need to design a follow-up mechanism that absorbs shear deformation is alleviated.

  In particular, in this embodiment, the sliding bearing 20 does not function until it receives an external force due to an earthquake motion that occurs extremely rarely. Therefore, the same equipment structure as that of a base-isolated building that does not have a plurality of base isolation layers in the height direction of the building Can be applied.

  On the other hand, when an extremely large earthquake such as a so-called 500-year interval earthquake occurs, the second seismic isolation layer 16 receives an external force due to an extremely rare earthquake motion, and the bearing portion 20A of the sliding bearing 20 is placed on the slide plate 20B. Slide. Thereby, seismic isolation performance can be improved compared with the base isolation building which is not equipped with the several base isolation layer in the building height direction. Further, the input energy can be effectively absorbed by the dynamic friction force when the support portion 20A slides on the slide plate 20B.

  In the present embodiment, since the second structure 12 is relatively displaced in the horizontal direction with respect to the first structure 11 when a seismic force of a predetermined value or more is input, the first seismic isolation layer 14 is deformed. The amount is reduced, and the horizontal displacement of the first structure 11 can be reduced. Thereby, the horizontal clearance between the first structure 11 and the foundation 100 can be designed to be small.

  Further, since the second seismic isolation layer 16 does not deform until an earthquake force of a predetermined value or more is input, the seismic isolation having a plurality of seismic isolation layers in the general building height direction not provided with the sliding bearing 20. Compared with a building, the deformation amount of the second seismic isolation layer 16 after a seismic force of a predetermined value or more is input can be reduced. Further, the response acceleration of the second structure 12 is also reduced. This effect will be described by comparing the base isolation structure of the comparative example shown in FIG. 4 with the base isolation structure of the example. In addition, the seismic isolation structure of an Example is taken as the structure similar to the structure shown by FIG. In FIG. 4, the same components as those in the present embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  As shown in FIG. 4A, the building 101 to which the seismic isolation structure of Comparative Example 1 is applied is not a seismic isolation structure having a plurality of seismic isolation layers in the building height direction, but the first seismic isolation layer 14. It is a structure with only. That is, the 1st seismic isolation layer 14 is provided between the foundation 100 and the structure 102, and this 1st seismic isolation layer 14 is the laminated rubber 18 which is a seismic isolation support, and the seismic isolation damping member which is not shown in figure. An oil damper is included.

  On the other hand, as shown in FIG. 4 (B), the building 103 to which the seismic isolation structure of Comparative Example 2 is applied has an isolation structure having a plurality of seismic isolation layers in the height direction of the building including the second seismic isolation layer 104. It is said to have a seismic structure. Specifically, a lower first structure 11 and an upper second structure 12 are provided, and a first seismic isolation layer that supports the first structure 11 is provided below the first structure 11. 14 is provided.

  A second seismic isolation layer 104 is provided between the first structure 11 and the second structure 12, and the second structure 12 is supported by the second seismic isolation layer 104. Here, in the present comparative example, the second seismic isolation layer 104 is configured to include a laminated rubber 18 that is a seismic isolation bearing and an oil damper that is a seismic isolation damping member (not shown), like the first seismic isolation layer 14. Yes. That is, it is set as the structure different from the seismic isolation structure which concerns on this embodiment by the point by which the sliding bearing 20 is not provided.

  For the buildings according to comparative example 1 and comparative example 2 configured as described above and the building according to the example, the acceleration of the second structure with respect to the magnification of the earthquake input is calculated, and the calculation result is shown in FIG. Indicated. Moreover, the horizontal deformation amount of the second seismic isolation layer with respect to the magnification of the earthquake input was calculated, and the calculation result is shown in FIG. In addition, the numerical value shown to the following Tables 1-3 was used for the item used for the calculation of the acceleration of a structure, and the amount of horizontal deformation as an example. Table 1 lists the specifications of the example, Table 2 lists the specifications of Comparative Example 1, and Table 3 lists the specifications of Comparative Example 2. Here, in Comparative Example 1, it is assumed that the second structure is fixed on the first structure, and the value is adjusted so as to have the same total weight as in Example and Comparative Example 2. In addition, it is assumed that the earthquake input magnification in FIG. Level 2 seismic ground motion corresponds to “very rare seismic ground motion” announced by the Ministry of Land, Infrastructure, Transport and Tourism Notification No. 38 of March 30, 2003.

  As shown in FIG. 3A, in Comparative Example 1 and Comparative Example 2, the acceleration of the second structure increases linearly as the earthquake input magnification increases. On the other hand, the acceleration of the second structure according to the example shows the same behavior as Comparative Example 1 and Comparative Example 2 until the earthquake input magnification reaches 1, but the earthquake input magnification is 1 It was confirmed that the amount of increase in the acceleration of the second structure becomes smaller as it becomes larger. As shown in FIG. 1, when the earthquake input magnification is larger than 1, the sliding bearing 20 of the second seismic isolation layer 16 functions, and the bearing portion 20A slides on the slide plate 20B. This is because the second structure 12 is relatively displaced in the horizontal direction with respect to the one structure 11.

  Next, as shown in FIG. 3 (B), the seismic isolation structure of Comparative Example 2 is not provided with a sliding support as a trigger member, so even if the earthquake input magnification is smaller than 1. It can be seen that the second seismic isolation layer functions and the second structure is horizontally displaced with respect to the first structure. On the other hand, the horizontal deformation amount of the second seismic isolation layer according to the example is substantially 0 until the magnification of the earthquake input reaches 1. That is, since the static frictional force of the sliding bearing 20 serves as a trigger load, the second structure is hardly horizontally displaced with respect to the first structure until an external force larger than the static frictional force is input. As a result, as described above, even when an elevator shaft and piping are disposed through the first structure and the second structure, these elevator shafts and piping with respect to the magnification 1 of the earthquake input. It has been confirmed that it is not necessary to provide a follow-up mechanism that absorbs shear deformation acting on the like. In the graph of FIG. 3B, when the earthquake input magnification is 1, the horizontal deformation amount of the second seismic isolation layer according to the example is 0, but the present invention is not limited to this. That is, the second structure may be horizontally displaced with respect to the first structure as long as the shear stress acting on the elevator shaft, piping, etc. is acceptable. For example, when the earthquake input magnification is 1, the second seismic isolation layer may be horizontally deformed by about several centimeters.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to such embodiment, Of course, in the range which does not deviate from the summary of this invention, it can implement in a various aspect. For example, the sliding bearing 20 of the present embodiment is configured to function when receiving an external force due to an extremely rare earthquake motion (level 2 earthquake motion), but is not limited thereto. For example, the sliding bearing 20 may be configured to function when an external force that is half of the external force due to the earthquake motion that occurs extremely rarely is received.

  Moreover, the seismic isolation structure according to the present invention is not limited to the configuration shown in FIG. 1, and various configurations can be applied. As an example, you may apply the seismic isolation structure which concerns on the 1st modification-6th modification shown by FIGS. In the following description, the same reference numerals are given to the same components as those in the embodiment, and the description will be omitted as appropriate.

(First modification)
As shown in FIG. 5A, in the base isolation structure according to the first modification of the present embodiment, a second base isolation layer 32 is provided between the first structure 11 and the second structure 12. The second seismic isolation layer 32 includes a double-sided sliding bearing 30 as a trigger member.

  The double-sided sliding support 30 includes a support portion 30A, an upper slide plate 30B, and a lower slide plate 30C. 30 A of support parts are formed in the substantially cylindrical shape from which both upper surface side and lower surface side turns into a sliding surface. For this reason, the support portion 30A is not fixed to either the first structure 11 or the second structure 12, and can be horizontally displaced with respect to both structures.

  The upper slide plate 30 </ b> B is disposed between the support portion 30 </ b> A and the second structure 12, and is fixed to the lower surface of the second structure 12. On the other hand, the lower slide plate 30 </ b> C is disposed between the support portion 30 </ b> A and the first structure 11, and is fixed to the upper surface of the first structure 11.

  Here, the static frictional force of the double-sided sliding bearing 30 serves as a trigger load, and the trigger is released when an external force equal to or greater than the static frictional force is input by an earthquake force equal to or greater than a predetermined value. Further, as an example, the present modification is configured such that the bearing portion 30A slides with respect to the upper slide plate 30B and the lower slide plate 30C when receiving an external force due to an extremely rarely generated earthquake motion.

  An upper stopper 36 is disposed around the upper slide plate 30B. The upper stopper 36 is fixed to the second structure 12 and extends from the second structure 12 to below the upper slide plate 30B. For this reason, the support portion 30 </ b> A is configured to slide only within the region surrounded by the upper stopper 36 with respect to the second structure 12.

  Similar to the upper stopper 36, a lower stopper 34 is disposed around the lower slide plate 30C. The lower stopper 34 is fixed to the first structure 11 and extends from the first structure 11 to above the lower slide plate 30C. For this reason, the support portion 30 </ b> A is configured to slide only within the region surrounded by the lower stopper 34 with respect to the first structure 11.

  The seismic isolation structure configured as described above has the same effect as the embodiment. That is, the double-sided sliding support 30 does not function and the first structure 11 and the second structure 12 are not displaced relative to each other until a seismic force due to an extremely rare earthquake motion is input. On the other hand, when a seismic force due to an extremely rare earthquake motion is input, the support portion 30A slides with respect to the upper slide plate 30B and the lower slide plate 30C.

  Further, in this modification, the amount of horizontal deformation of the second seismic isolation layer 32 is obtained by adding the relative displacement between the support portion 30A and the lower slide plate 30C to the relative displacement between the upper slide plate 30B and the support portion 30A. . Therefore, vertical force lines (that is, the positions of the respective support portions 30A) that transmit the weight of the second structure 12 in the second seismic isolation layer 32 and the weight of the second structure 12 in the first structure 11 are received. Relative displacement with a vertical force line (that is, each column position in the first structure 11) can be significantly suppressed as compared with the above-described embodiment. As a result, the magnitude of the eccentric moment due to the weight of the second structure 12 generated in the first structure 11 can be reduced.

  In addition, although the double-sided sliding support 30 which concerns on this modification was comprised so that the dynamic friction coefficient of an upper surface side and the dynamic friction coefficient of a lower surface side might be substantially the same, it is not limited to this. For example, the friction coefficient on the lower surface side may be configured to be smaller than the dynamic friction coefficient on the upper surface side. In this case, since the lower sliding surface slides first and comes into contact with the lower stopper 34, the upper sliding surface slides. Therefore, the upper stopper 36 can be removed and the upper slide plate 30B can be formed larger, which is more excessive. Can be prepared for earthquake input.

(Second modification)
Next, the seismic isolation structure according to the second modification of the present embodiment will be described. As shown in FIG. 5B, in the seismic isolation structure according to this modification, a second seismic isolation layer 42 is provided between the first structure 11 and the second structure 12, and this first The 2 seismic isolation layer 42 includes a steel damper 40 as a trigger member and laminated rubber (not shown).

  The steel damper 40 includes a plurality of U-shaped dampers 43 formed of ductile steel, and in this modification, includes four U-shaped dampers 43 (in FIG. 5B, two U-shaped dampers 43). Only the character damper 43 is shown). Each U-shaped damper 43 includes an upper straight portion 43B, a lower straight portion 43C, and a curved portion 43A, and is formed in a substantially U shape.

  The upper straight portion 43 </ b> B extends linearly along the lower surface of the second structure 12 and is fastened by an upper mounting seat 44 and a bolt 48 attached to the lower surface of the second structure 12. The lower straight portion 43 </ b> C extends substantially parallel to the upper straight portion 43 </ b> B along the upper surface of the first structure 11, and a lower mounting seat 46 and a bolt 48 attached to the upper surface of the first structure 11. It is concluded by

  Here, the upper straight portion 43B and the lower straight portion 43C are connected by a bending portion 43A. The curved portion 43A is formed integrally with the upper straight portion 43B and the lower straight portion 43C, and is curved outward.

  The pair of U-shaped dampers 43 illustrated in FIG. 5B are arranged in the left-right direction on the paper surface such that the curved portions 43A face each other. In addition, a pair of steel dampers (not shown) are arranged in the depth direction of the paper surface. Here, the yield load of the U-shaped damper 43 is set so as to be plastically deformed when a seismic force due to an extremely rare earthquake motion is input. For this reason, the U-shaped damper 43 is not deformed during an earthquake that occurs relatively frequently, and the first structure 11 and the second structure 12 are integrally displaced horizontally.

  The seismic isolation structure configured as described above has the same effect as the embodiment. That is, the steel damper 40 is not deformed and the first structure 11 and the second structure 12 are not displaced relative to each other until a seismic force due to an extremely rare earthquake motion is input. On the other hand, when a seismic force caused by an extremely rare earthquake motion is input, the steel damper 40 is plastically deformed, and the second structure 12 is relatively displaced with respect to the first structure 11. Moreover, the input energy by a seismic motion can be absorbed by carrying out plastic deformation.

  In addition, in this modification, although the U-shaped steel material damper 40 was applied, you may apply not only this but the steel material damper of another shape. For example, a metal damper such as a lead damper or a honeycomb damper may be applied. Further, a sliding bearing and a steel damper may be combined. For example, in the seismic isolation structure of FIG. 1, the steel damper 40 of FIG.

(Third Modification)
Next, a seismic isolation structure according to a third modification of the present embodiment will be described. As shown in FIG. 6A, in the building 50 to which the seismic isolation structure according to the present modification is applied, the first structure 51 is supported by the first seismic isolation layer 14, and this first structure The lower part of 51 is formed horizontally long. And the 2nd structure 52 is supported via the 2nd seismic isolation layer 16 by this lower part. Thus, the first structure 51 and the second structure 52 constitute a so-called twin tower.

(Fourth modification)
Next, a seismic isolation structure according to a fourth modification of the present embodiment will be described. As shown in FIG. 6B, in the building 60 to which the seismic isolation structure according to this modification is applied, the intermediate base plate 61 is supported by the first seismic isolation layer 14. A first structure 62 and a second structure 63 are formed on the intermediate base plate 61. Further, a second seismic isolation layer 16 is provided between the second structure 63 and the intermediate base plate 61, and the second structure 63 is connected to the intermediate base plate 61 via the second base isolation layer 16. Supported on top. Thereby, the 1st structure 62 and the 2nd structure 63 comprise what is called a twin tower like the 3rd modification.

(5th modification)
Next, a seismic isolation structure according to a fifth modification of the present embodiment will be described. As shown in FIG. 7, in the building 70 to which the seismic isolation structure according to this modification is applied, an intermediate foundation plate 72 as a first structure is supported by the first seismic isolation layer 14, and this intermediate foundation A second structure 71 is supported on the plate 72 via the second seismic isolation layer 16.

(Sixth Modification)
Next, a seismic isolation structure according to a sixth modification of the present embodiment will be described. As shown in FIG. 8, in the building 80 to which the seismic isolation structure according to this modification is applied, the intermediate base plate 81 as the first structure is provided on the first seismic isolation layer 14 as in the fifth modification. The second structure 83 is supported on the intermediate base plate 81 via the second seismic isolation layer 16.

  Further, in this modification, a step is provided on the foundation 100, and a portion of the foundation 100 located below the outer peripheral portion of the second structure 83 is formed higher than the first seismic isolation layer 14. A slide support 82 is provided between the foundation 100 and the second structure 83, and the outer periphery of the second structure 83 is supported by the slide support 82.

  Here, the sliding support 82 includes a support portion 82A and a slide plate 82B, and the support portion 82A is configured to slide on the slide plate 82B. Further, the static friction force in the sliding bearing 82 is set to be smaller than the static friction force in the sliding bearing 20 between the intermediate base plate 81 and the second structure 83. For this reason, when the laminated rubber 18 of the first seismic isolation layer 14 is deformed by an earthquake, the sliding support 82 is configured to slide on the slide plate 82B in accordance with the deformation. That is, the same slip displacement as the deformation of the first seismic isolation layer 14 occurs in the slide bearing 82.

  The base isolation structure according to the third to sixth modifications configured as described above has the same effects as the base isolation structure according to the embodiment.

11 First structure 12 Second structure 14 First seismic isolation layer 16 Second seismic isolation layer 20 Sliding bearing (trigger member)
30 Double-sided sliding support (trigger member)
40 Steel damper (trigger member)
51 1st structure 52 2nd structure 62 1st structure 63 2nd structure 71 2nd structure 72 Intermediate base plate (1st structure)
81 Intermediate foundation plate (first structure)
83 Second structure

Claims (3)

A first seismic isolation layer supporting the first structure;
A second seismic isolation layer provided on the first structure and supporting the second structure;
A trigger member that is provided in the second seismic isolation layer and slides or deforms when a seismic force of a predetermined value or more is input, and relatively displaces the second structure in the horizontal direction with respect to the first structure. When,
Seismic isolation structure.   The seismic isolation structure according to claim 1, wherein the trigger member is a sliding bearing or a steel damper.   The trigger member slides or deforms when the second seismic isolation layer receives an external force due to an earthquake motion that occurs very rarely, and the second structure body is relative to the first structure body in the horizontal direction. The seismic isolation structure according to claim 1 or 2 to be displaced.

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