JP6210668B2 - Seismic isolation structure - Google Patents

Description

  The present invention relates to a seismic isolation structure having a plurality of seismic isolation layers.

  A base-isolated structure has been proposed in which a structure composed of a plurality of structures stacked via an intermediate base layer is supported by a base base layer. For example, Patent Literature 1 discloses a base-isolated building in which a plurality of building blocks are stacked on a foundation and seismic isolation devices are installed between the building blocks and between the foundation and the building blocks.

  Such a base-isolated building has a long natural period, so it has the effect of reducing the shaking of the building against short-period ground motions. Resonates and shakes greatly.

Japanese Patent Laid-Open No. 1-263373

  This invention considers the fact which concerns, and makes it a subject to provide the seismic isolation structure which can reduce the shaking of a structure with respect to the short period and long period ground motion.

The invention of the first aspect is provided in a structure composed of a plurality of structures stacked via an intermediate seismic isolation layer, a bottom seismic isolation layer that supports the structure, and the intermediate seismic isolation layer. A rigidity imparting device that reduces or increases the number of mass points of the vibration system constituted by the structure, the intermediate seismic isolation layer, and the lowermost seismic isolation layer by fixing or unfixing the intermediate seismic isolation layer; This is a seismic isolation structure.

In the first aspect of the invention, during the earthquake, the intermediate seismic isolation layer is fixed or released (if there are multiple intermediate isolation layers, at least one intermediate isolation layer is fixed or released) Reduce or increase the number of mass points in the vibration system of seismic structures. As a result, the natural period of the vibration system of the base-isolated structure is changed, the natural period and the vibration period of the ground motion are made different to prevent resonance, and the structure shake (acceleration response and deformation response) Can be reduced. That is, the shaking of the structure can be reduced with respect to short-period and long-period ground motions.

  For example, if multiple seismic isolation layers are provided in the base isolation structure, all intermediate base isolation layers can be unlocked so that the structure can be effectively reduced in response to short-period ground motion. The seismic isolation structure is made into a multi-mass point vibration system (long-period seismic isolation structure), and when long-period ground motion occurs, at least one intermediate seismic isolation layer is fixed Reduce the number of mass points in the vibration system. Thereby, the natural period of the vibration system of the seismic isolation structure is shortened, and the shaking of the structure can be reduced.

According to the second aspect of the invention, in the base isolation structure of the first aspect , all the intermediate base isolation layers are fixed, and the number of mass points of the vibration system is one.

In the second aspect of the invention, the rigidity of the intermediate base isolation layer is increased (the intermediate base isolation layer is fixed) and the natural period of the vibration system of the base isolation structure and the vibration period of the ground motion are made different. The deformation amount response of the object can be effectively reduced.

The invention of a third aspect is the damper capable of adjusting the damping applied to the intermediate seismic isolation layer in the base isolation structure of the first or second aspect .

In the invention of the third aspect , by using the damper as the rigidity imparting device, the damping imparted to the intermediate seismic isolation layer can be increased or decreased to fix and release the intermediate seismic isolation layer. Thereby, the intermediate seismic isolation layer can be reliably fixed or released.

According to a fourth aspect of the present invention, in the base isolation structure according to any one of the first to third aspects , the bottom base isolation layer is a basic base isolation layer.

In the invention of the fourth aspect , the shaking (acceleration response and deformation amount response of the structure) supported by the base seismic isolation layer can be reduced.

  Since this invention set it as the said structure, the shaking of a structure can be reduced with respect to the short period and long period ground motion.

It is an elevation view which shows the building which concerns on embodiment of this invention. It is explanatory drawing which shows the vibration system model of the building which concerns on embodiment of this invention. It is a diagram which shows the effect of the building which concerns on embodiment of this invention. It is an elevation view which shows the modification of the building which concerns on embodiment of this invention. It is explanatory drawing which shows the vibration system model of the modification of the building which concerns on embodiment of this invention. It is explanatory drawing which shows the modification of the rigidity provision apparatus which concerns on embodiment of this invention. It is an elevation view which shows the modification of the building which concerns on embodiment of this invention.

  Embodiments of the present invention will be described with reference to the drawings. First, a building as a seismic isolation structure according to an embodiment of the present invention will be described.

  As shown in the elevation view of FIG. 1, a reinforced concrete building 10 as a base isolation structure has a structure 12 and a base base isolation layer 14 as a bottom base isolation layer. The structure 12 is composed of two structures 12A and 12B stacked in the vertical direction via the intermediate seismic isolation layer 16, and the base seismic isolation layer 14 supports the structure 12 in isolation. In the basic seismic isolation layer 14 and the intermediate seismic isolation layer 16, a plurality of laminated rubber bearings 18 as seismic isolation devices and oil dampers 20 as rigidity imparting devices are arranged.

  A laminated rubber bearing 18 provided in the base seismic isolation layer 14 is installed on a foundation 24 constructed in the ground 22 to support the structure 12 (structures 12A and 12B) in isolation. A laminated rubber bearing 18 provided in the intermediate seismic isolation layer 16 is installed on the structure 12A to support the structure 12B in isolation.

  The oil damper 20 provided in the basic seismic isolation layer 14 connects the foundation 24 and the structure 12 </ b> A and imparts damping to the basic seismic isolation layer 14. The oil damper 20 provided in the intermediate seismic isolation layer 16 connects the structural body 12A and the structural body 12B and imparts attenuation to the intermediate seismic isolation layer 16. The oil damper 20 can adjust the magnitude of attenuation applied to the base isolation layer 14 and the intermediate isolation layer 16.

  Further, the oil damper 20 can give the intermediate seismic isolation layer 16 overdamped and increase the rigidity of the intermediate seismic isolation layer 16. In the present embodiment, this is expressed as “fix the intermediate seismic isolation layer 16”. “Fixing the intermediate seismic isolation layer 16” means that the structures 12 </ b> A and 12 </ b> B arranged in the vertical direction via the intermediate seismic isolation layer 16 are integrated. That is, during an earthquake, the structure 12A and the structure 12B shake together.

  In addition, the oil damper 20 can reduce or eliminate the attenuation imparted to the intermediate seismic isolation layer 16 to reduce the rigidity of the intermediate seismic isolation layer 16. In the present embodiment, this is expressed as “releasing the intermediate seismic isolation layer 16”. “Unfixing the intermediate isolation layer 16” means that the intermediate isolation layer 16 is released from the fixed state, and the structure 12B placed on the intermediate isolation layer 16 is moved to the intermediate isolation layer 16. It means to be supported by seismic isolation. That is, during an earthquake, the structure 12B moves relative to the structure 12A and shakes.

  Next, the operation and effect of the building as the seismic isolation structure according to the embodiment of the present invention will be described.

  In the building 10 of the present embodiment, as shown in FIG. 1, the base isolation layer 14, the structure 12 </ b> A, the intermediate isolation layer 16, and the structure are fixed by releasing or fixing the intermediate isolation layer 16 during an earthquake. The number of mass points of the vibration system (hereinafter referred to as “vibration system S”) of the building 10 constituted by 12B is reduced or increased. As a result, the natural period of the vibration system S of the building 10 is changed, and the natural period and the vibration period of the ground motion are made different to prevent resonance, and the structure 12 is shaken (acceleration response and deformation amount response of the structure 12). Can be reduced. That is, the shaking of the structure 12 can be reduced with respect to short-period and long-period ground motions, and the building 10 safe against various ground motions can be constructed.

This effect will be described in more detail. In FIG. 1, the structure 12 is supported by the basic seismic isolation layer 14 in isolation (the overdamping is not given to the basic isolation layer 14 by the oil damper 20, and the foundation 24), the structure 12A is relatively movable with respect to 24), and the intermediate seismic isolation layer 16 is overdamped from the oil damper 20 provided in the intermediate seismic isolation layer 16 to provide the intermediate seismic isolation layer. When 16 are fixed, as shown in FIG. 2 (a), the number of mass of the vibration system S is turned one vibration system S is equivalent 1 mass vibration system S _1. In FIG. 2 (a), the structure 12A having a mass _{m 1,} the structure body 12B having a mass _{m 2,} the structure 12 has a mass _{M 1,} which is integral (mass points), basic seismic isolation layer 14 structural model of the equivalent SDOF vibration system S ₁ which is seismic isolation supported on the base 24 via a are shown.

Further, when the damping provided to the intermediate seismic isolation layer 16 from the oil damper 20 provided in the intermediate seismic isolation layer 16 is reduced or eliminated and the intermediate seismic isolation layer 16 is released from the fixed state, as shown in FIG. , the number of mass of the vibration system S becomes two, the vibration system S is equivalent two-mass vibration system S _2. In FIG. 2 (b), a structure 12A (mass point) having a mass m ₁ is supported on a base 24 via a base seismic isolation layer 14, and a structure 12B (mass point) having a mass m ₂ is provided. , structural model of the equivalent two-mass vibration system S ₂ which are seismic isolation supported via intermediate base isolation layer 16 over the structure 12A is shown.

  Here, if the number of mass points of the vibration system S increases, the natural period of the entire building 10 increases. If the number of mass points of the vibration system S decreases, the natural period of the entire building 10 decreases. By fixing or releasing the seismic layer 16, the natural period of the entire building 10 can be changed. That is, by fixing or releasing the fixing of the intermediate seismic isolation layer 16, the period of earthquake motion during an earthquake and the natural period of the entire building 10 can be shifted. Accordingly, the building 10 can be prevented from resonating, and the shaking of the structure 12 (acceleration response and deformation amount response of the structure 12) can be reduced.

  For example, in the case of an earthquake that occurs directly below and near the site, as shown in the graph of FIG. 3, the seismic wave 26 has a short-period vibration component with a dominant period of about 0.5 to 2 seconds. By unfixing the layer 16 (arrow 30), the natural period of the entire building 10 can be increased to about 6 seconds, and the shaking of the structure 12 can be suppressed.

  For example, in the case of an earthquake that occurs far from the site, as shown in the graph of FIG. 3, the seismic wave 28 has a long-period vibration component with a dominant period of about 5 to 8 seconds. By fixing (arrow 32), the natural period of the whole building 10 can be made into a medium period of about 4 seconds, and the shaking of the structure 12 can be suppressed.

  It should be noted that the seismic motion period at the time of the earthquake and the natural period of the entire building 10 may be shifted by fixing the intermediate seismic isolation layer 16. The natural period of the entire building 10 may be shifted. However, the smaller the number of mass points of the vibration system S, the smaller the deformation amount of the structure 12 with respect to the earthquake motion. It is preferable to reduce the shaking of the structure 12 by changing the natural period of the entire 10.

  Furthermore, in the building 10 of the present embodiment, the rigidity imparting device is a damper (oil damper 20), thereby increasing or decreasing the attenuation imparted to the intermediate seismic isolation layer 16, thereby fixing and releasing the intermediate seismic isolation layer 16. It can be performed. Thereby, the intermediate seismic isolation layer 16 can be reliably fixed or released.

  The embodiment of the present invention has been described above.

  In addition, in this embodiment, as shown in FIG. 1, the example which comprised the structure 12 by two structure 12A, 12B was shown, However, The structure 12 is laminated | stacked via the middle seismic isolation layer. The structure 12 may be configured by stacking three or more structures alternately with the intermediate seismic isolation layer in the vertical direction.

  In the elevation view of FIG. 4, there is a reinforced concrete building 36 as a seismic isolation structure having a structure 34 constituted by three structures 12A, 12B, and 12C laminated via an intermediate seismic isolation layer 16. It is shown. For convenience of explanation, the intermediate seismic isolation layer 16 provided between the structure 12A and the structure 12B is referred to as an intermediate seismic isolation layer 16A, and the intermediate isolation provided between the structure 12B and the structure 12C. The seismic layer 16 is an intermediate seismic isolation layer 16B.

  In the building 36, as shown in FIGS. 5A to 5D, the number of mass points of the vibration system S can be variously changed by fixing or unfixing the intermediate seismic isolation layers 16A and 16B.

FIG. 5A shows a state in which the structure 34 is isolated from the base isolation layer 14 (no overdamping is given to the base isolation layer 14 by the oil damper 20, In the state in which the structure 12A is relatively movable), the structure 12A (mass point) having the mass m ₁ is the foundation via the base isolation layer 14 by releasing the fixing of the intermediate isolation layers 16A and 16B. The structure 12B (mass point) having the mass m ₂ supported on the base 24 is isolated from the structure 12A via the intermediate seismic isolation layer 16A, and the structure 12C (mass point) having the mass m ₃ is supported. structural model of the equivalent 3 mass system S ₃ being the seismic isolation supported via intermediate base isolation layer 16B over the structure 12B is shown.

In FIG. 5 (b), the structure 34 is isolated and supported by the base isolation layer 14 (the base damper 24 is not overdamped by the oil damper 20 and In the state in which the structure 12A is relatively movable), the structure 12A (mass point) having the mass m ₁ is removed from the basic immunity by releasing the fixation of the intermediate isolation layer 16A and fixing the intermediate isolation layer 16B. A structure 38 (mass point) having a mass M ₂ , which is supported on the base 24 via the seismic layer 14 and is integrated with a structure 12 B having a mass m ₂ and a structure 12 C having a mass m _3. structural model of the equivalent two-mass system S ₄ which are the seismic isolation supported via intermediate base isolation layer 16A on the structure 12A is shown.

FIG. 5C shows a state in which the structure 34 is isolated from the base isolation layer 14 (no overdamping is given to the base isolation layer 14 by the oil damper 20). In the state in which the structure 12A is relatively movable), the intermediate seismic isolation layer 16A is fixed and the intermediate seismic isolation layer 16B is unfixed, whereby the structure 12A having the mass m ₁ and the mass m ₂ are obtained. structure 40 and structure 12B having has a mass M _1, which is integral (mass points) are seismic isolation supported on the base 24 through the underlying base isolation layer 14, the structure 12C having a mass m ₃ (mass points) There has been a structural model of the equivalent two-mass system S ₅ which is seismic isolation supported on structure 40 via an intermediate base isolation layer 16B (structure 12B) is shown.

In FIG. 5 (d), the structure 34 is isolated and supported by the basic seismic isolation layer 14 (overdamping is not given to the basic seismic isolation layer 14 by the oil damper 20, in state) structure 12A is in relatively movable, by fixing the intermediate base isolation layer 16A, the 16B, a structure 12A having a mass _{m 1,} the structure body 12B having a mass _{m 2,} the mass m structures 12C and structure equivalent SDOF system S ₆ which are seismic isolation supported on the base 24 via a structure 42 (mass point) of basic seismic isolation layer 14 having a mass M ₃ which is integral with a ₃ The model is shown.

  Therefore, by fixing or unfixing at least one of the intermediate seismic isolation layers 16A and 16B in the building 36 and reducing or increasing the number of mass points of the vibration system S of the building 36, the vibration system S of the building 36 The natural period is changed, and the natural period and the vibration period of the ground motion are made different to prevent resonance, and the vibration of the structure 34 (acceleration response and deformation amount response of the structure 34) can be reduced. That is, the shaking of the structure 34 can be reduced with respect to short-period and long-period ground motions.

For example, as can be effectively reduced vibration of the structure 34 relative to the ground motion of the short period, leave all intermediate isolation layer 16A, 16B and by unlocking the building 36 to the equivalent 3 mass vibration system S ₃ (Longer seismic isolation structure) When long-period ground motion occurs, fix at least one of the intermediate seismic isolation layers 16A, 16B to reduce the number of mass points of the vibration system S of the building 36 (Equivalent 2-mass system S ₄ , equivalent 2-mass system S ₅ , or equivalent 1-mass system S ₆ ). Thereby, the natural period of the vibration system S of the building 36 is shortened, and the shaking of the structure 34 can be reduced.

As described above, the method of fixing at least one of the intermediate seismic isolation layers 16A and 16B and reducing the number of mass points of the vibration system S increases the rigidity of the intermediate seismic isolation layer and increases the vibration system S of the building 36. Since the natural period and the vibration period of the ground motion are made different, the deformation amount response of the structure 34 can be effectively reduced. Incidentally, all intermediate isolation layer 16A, 16B are fixed (to the equivalent SDOF system _{S 6)} of is more preferable.

  In addition, when fixing any of the plurality of intermediate isolation layers (in the example of FIG. 4, the intermediate isolation layers 16 </ b> A and 16 </ b> B), the upper intermediate isolation layer (in the example of FIG. 4, It is preferable to fix the intermediate seismic isolation layer 16B).

  Furthermore, in this embodiment, the example which made the building 10 as a seismic isolation structure the reinforced concrete structure was shown, but this embodiment is a reinforced concrete structure, a steel structure, a steel frame reinforced concrete structure, a CFT structure (Concrete-Filled Steel Tube: It can be applied to seismic isolation structures of various structures and scales such as filled steel pipe concrete structures) and their mixed structures.

  Moreover, although the example which used the laminated rubber bearing 18 was shown as this seismic isolation apparatus in this embodiment, the seismic isolation apparatus should just be what can support a structure in isolation.

  Furthermore, in this embodiment, although the example which used the rigidity imparting apparatus as the oil damper 20 was shown, what is necessary is just to be able to make the rigidity of the intermediate seismic isolation layer 16 high. For example, as shown in FIGS. 6A and 6B, the rigidity imparting device may be a shear pin 44. FIG. 6A shows a state in which the shear pin 44 is accommodated only in the accommodation portion 46 provided on the lower surface of the structure 12B, and the rigidity of the shear pin 44 is not imparted to the intermediate seismic isolation layer 16. “The intermediate seismic isolation layer 16 is fixed”.

  In FIG. 6 (b), the shear pin 44 moves downward, and the shear pin 44 is provided in both the accommodation portion 46 provided on the lower surface of the structure 12B and the accommodation portion 48 provided on the upper surface of the structure 12A. The housed state is shown, and the intermediate seismic isolation layer 16 is in a state of “fixing the intermediate seismic isolation layer 16” in which the rigidity of the shear pin 44 is given.

  In addition, the timing of fixing or releasing the fixing of the intermediate seismic isolation layer 16 shown in the present embodiment may be appropriately determined, for example, when a P wave is detected or after a period of seismic motion is measured.

  Further, in the present embodiment, the example in which the bottom base isolation layer is the base base isolation layer 14 is shown, but the bottom base isolation layer is configured by a plurality of structures stacked via the intermediate base isolation layer. This means the seismic isolation layer that supports the structure. That is, the lowest seismic isolation layer should just be arrange | positioned in the lowest layer of the seismic isolation layers which a building has. Therefore, for example, like the building 50 shown in the elevation view of FIG. It may be a seismic isolation layer.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to such embodiment at all, Of course, in the range which does not deviate from the summary of this invention, it can implement in a various aspect.

10, 36, 50 Building (Seismic isolation structure)
12, 34 Structures 12A, 12B, 12C, 54 Structure 14 Base base isolation layer (bottom base isolation layer)
16, 16A, 16B Middle seismic isolation layer 20 Oil damper (rigidity imparting device)
44 Shear pin (rigidity imparting device)
52 Base isolation layer (the bottom base isolation layer)

Claims (4)

A structure composed of a plurality of structures stacked via an intermediate seismic isolation layer;
A bottom seismic isolation layer supporting the structure;
The natural period of the vibration system provided in the intermediate base isolation layer and configured by the structure, the intermediate base isolation layer, and the bottom base isolation layer is different from the vibration period of the ground motion acting on the structure. as such, the intermediate seismic isolation layer to be integrated the structure located above and below the fixed intermediate isolation layer to reduce the number of mass points of the vibrating system, or the intermediate base isolation layer and unlocking the A rigidity imparting device that increases the number of mass points of the vibration system by allowing relative movement of the structures disposed above and below the intermediate seismic isolation layer;
A base-isolated structure.   The seismic isolation structure according to claim 1, wherein all the intermediate seismic isolation layers are fixed so that the number of mass points of the vibration system is one.   The seismic isolation structure according to claim 1, wherein the rigidity imparting device is a damper capable of adjusting a damping imparted to the intermediate seismic isolation layer.   The seismic isolation structure according to any one of claims 1 to 3, wherein the bottom base isolation layer is a base isolation layer.

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