JP7081745B2 - Seismic isolation structure - Google Patents

Description

The present invention relates to a seismic isolation structure.

The following Patent Document 1 describes a seismic isolated building built in a pit. In this seismic isolated building, a seismic isolation device is installed on the floor slab of the pit, and the seismic isolation device supports the building.

Japanese Patent Application Laid-Open No. 2003-90146

In the seismic isolated building of Patent Document 1, when the displacement amount of the seismic isolation device exceeds the allowable displacement due to the seismic motion, the upper part and the lower part of the seismic isolation device in the seismic isolated building come into contact with each other and are damaged. There is a risk.

In view of the above facts, an object of the present invention is to provide a seismic isolation structure capable of reducing the displacement amount of the seismic isolation device.

The seismic isolation structure according to claim 1 includes a lower structure, a seismic isolation device mounted on the upper part of the lower structure, an upper structure supported by the seismic isolation device, and the lower structure or the upper part. A reaction force that protrudes vertically from one side of the structure and has a cushioning member attached to the side surface, and a reaction force that protrudes vertically from the lower structure or the other side of the upper structure and faces the cushioning member. The horizontal distance between the shock absorber and the reaction force body is set to be equal to or less than the allowable displacement of the seismic isolation device, and the breaking load of the cushioning member is smaller than the breaking load of the seismic isolation device .

In the seismic isolation structure of claim 1, when the upper structure and the lower structure move relative to each other in the lateral direction during an earthquake, the support column protruding upward from the lower structure and the reaction force protruding downward from the upper structure. It comes in contact with the body. Alternatively, the reaction force body protruding upward from the lower structure and the support column protruding downward from the upper structure come into contact with each other.

A cushioning member is attached to the column, and the horizontal distance between the cushioning member and the reaction force is set to be equal to or less than the allowable displacement of the seismic isolation device. Therefore, when the upper structure and the lower structure move relative to each other in the lateral direction, the shock absorber and the reaction force come into contact with each other before the displacement of the seismic isolation device reaches the allowable displacement. At this time, the cushioning member is compressed by the reaction force and resists the seismic force. As a result, the amount of displacement of the seismic isolation device can be reduced. In addition, damage to the seismic isolation device can be suppressed.

In the seismic isolation structure of claim 2, the cushioning member is attached to both side surfaces of the support column.

According to the seismic isolation structure according to claim 2, since the cushioning members are attached to both side surfaces of the column, it is possible to resist the seismic force on both sides of the vibration swaying from side to side. Therefore, the effect of reducing the displacement of the seismic isolation device and the effect of suppressing damage are high.
In the seismic isolation structure of claim 3, the breaking load of the column due to bending or shearing is larger than the breaking load of the cushioning member and smaller than the breaking load of the seismic isolation device.
In the seismic isolation structure of claim 4, the reaction force body is integrally formed with a beam provided on the lower structure or the other of the upper structure and a footing for fixing the seismic isolation device.

According to the seismic isolation structure according to the present invention, the displacement amount of the seismic isolation device can be reduced.

(A) is a vertical sectional view showing a building to which the seismic isolation structure according to the embodiment of this invention is applied, and (B) is the BB line sectional view of (A). (A) is a vertical sectional view showing a state in which the upper structure of the building to which the seismic isolation structure according to the embodiment of the present invention is applied is laterally displaced with respect to the lower structure, and (B) is (A). ) Is a cross-sectional view taken along the line BB. It is a stress-strain diagram of the steel frame strut, the fender, and the structure which combined these in the seismic isolation structure which concerns on embodiment of this invention. (A) is a vertical cross-sectional view showing a modified example in which a steel frame strut is attached to an upper structure in the seismic isolation structure according to the embodiment of the present invention, and (B) is a vertical cross-sectional view showing two steel strut columns and each having a fender. It is a vertical sectional view which shows the modification which attached one by one.

(building)
The seismic isolation structure according to the embodiment of the present invention is for suppressing damage to the seismic isolation device 16 installed between the lower structure 12 and the upper structure 14 in the building 10 shown in FIG. 1 (A). It is a seismic isolation structure equipped with a damage suppression mechanism.

The lower structure 12 is a reinforced concrete column-beam structure formed by joining a beam 12B to a column 12A, and a slab 12C is erected on the beam 12B at the upper end of the lower structure 12.

The beam 12B and the slab 12C are integrally formed, and their upper surfaces are substantially flush with each other. On the upper surface of the beam 12B and the slab 12C (the upper end surface of the lower structure 12), a footing 12D (pedestal of the seismic isolation device 16) protruding upward is formed above the column 12A. The lower flange 16B of the seismic isolation device 16 is bolted to the footing 12D.

The upper structure 14 is a reinforced concrete column-beam structure formed by joining a beam 14B to a column 14A, and a slab 14C is erected on the beam 14B at the lower end of the upper structure 14.

The beam 14B and the slab 14C are integrally formed, and their upper surfaces are substantially flush with each other. From the lower surface of the beam 14B and the slab 14C (the lower end surface of the upper structure 14), the footing 14D (the receiving seat of the seismic isolation device 16) projects downward below the column 14A. The footing 14D is placed on the upper flange 16C of the seismic isolation device 16, and the seismic isolation device 16 is bolted.

The seismic isolation device 16 is configured by fixing the upper flange 16C and the lower flange 16B above and below the laminated rubber 16A. Is difficult to convey to the superstructure 14.

(Damage suppression mechanism)
A steel column 20 made of H-shaped steel is installed on the beam 12B of the lower structure 12. The lower end of the steel frame column 20 is embedded in the center of the span of the beam 12B and protrudes upward from the beam 12B. Further, as shown in FIG. 1B, the steel frame columns 20 are arranged so that the strong axial direction (extending direction of the web 22) is along the extending direction (axis CL) of the beam 12B. Further, as shown in FIG. 1A, a stiffening plate 26 is provided between the flanges 24 at the upper end of the steel frame column 20.

In both flanges 24 of the steel frame column 20, a fender 30 is used as a cushioning member on both outer surfaces of the portion stiffened by the stiffening plate 26 (the surface of the steel frame column 20 that intersects the extending direction of the beam 12B). It is attached via 32. The fender 30 is a rubber bearing having a substantially hollow conical shape whose diameter is reduced from the flange 24 toward the side of the steel frame column 20, and is in the compression direction (extending direction of the web 22) and the shearing direction (extending the flange 24). It can exert resistance to the input of force in the direction).

The steel frame columns 20 and the fenders 30 are provided on both the beams 12B along the X and Y directions orthogonal to each other. The X direction and the Y direction are extension directions of the beams 12B and 14B, and do not indicate a specific direction or the like.

A reaction force body 40 made of concrete is installed on the beam 14B of the superstructure 14. The reaction force body 40 includes a fixing portion 42 integrally formed with the beam 14B and the footing 14D, and a pressing portion 44 protruding downward from the fixing portion 42. The fixing portion 42 and the pressing portion 44 are integrally formed.

The pressing portion 44 is arranged so as to face the fender 30 in elevation and plan views. The horizontal distance (distance L) between the pressing portion 44 and the fender 30 is set to be equal to or less than the allowable displacement of the laminated rubber 16A of the seismic isolation device 16.

That is, as shown in FIGS. 2A and 2B, for example, when the lower structure 12 and the upper structure 14 are relatively displaced in the X direction by a distance L in the event of an earthquake, the pressing portion 44 of the reaction force body 40 And the fender 30 come into contact with each other, but the deformation amount of the laminated rubber 16A at this time is less than or equal to the breaking deformation amount.

The yield load (elastic limit load) of the steel frame column 20 is larger than 1.0 times the breaking load of the fender 30 and 1.1 times or less. Further, the yield load and the breaking load (plastic limit load) of the steel frame column 20 are smaller than the breaking load of the laminated rubber 16A.

As shown in FIGS. 1A and 1B, the reaction force bodies 40 are arranged on both sides of the steel frame column 20 so as to face the fender 30. Therefore, when the lower structure 12 and the upper structure 14 are relatively displaced during an earthquake, the two fenders 30 attached to both flanges 24 of the steel frame column 20 alternately come into contact with the reaction force body 40.

Further, the reaction force body 40 is provided on both the beam 14B along the X direction and the Y direction orthogonal to each other, like the steel frame support 20 and the fender 30. Therefore, even when the lower structure 12 and the upper structure 14 are relatively displaced not only in the X direction but also in the Y direction, the fender 30 comes into contact with the reaction force body 40.

(Action / effect)
In the seismic isolation structure according to the embodiment of the present invention, after the lower structure 12 and the upper structure 14 are relatively displaced in the X direction by a distance L, that is, the pressing portion 44 of the reaction force body 40 and the fender 30 The relationship between the internal stress σ and the strain ε generated in the steel column 20 and the fender 30 after the contact with each other will be described with reference to FIG.

In FIG. 3, the relationship between the internal stress σ generated in the steel frame column 20 and the strain ε when an external force in the direction along the web 22 acts on the steel frame column 20 is shown by a curve F. As shown by the curve F, the yield stress when the steel frame column 20 yields is σ1, and the yield strain is ε1. When an external force of σ1 or more per unit area acts on the steel frame column 20, the steel frame column 20 yields, plastically deforms, and breaks at a strain amount ε2.

Further, in FIG. 3, the internal stress σ and the strain ε generated in the fender 30 when an external force in the direction along the axial direction of the cone acts on the fender 30 having a substantially hollow cone shape. The relationship is shown by the curve G. As shown by the curve G, the breaking stress when the fender 30 breaks is σ3, and the yield strain is ε3. When an external force of σ3 or more per unit area acts on the steel frame column 20, the fender 30 breaks with a strain amount of ε3.

In the seismic isolation structure according to the first embodiment, the steel frame column 20 and the fender 30 are simultaneously pressed by the reaction force body 40 at the time of an earthquake. Assuming that the external force per unit area for pressing the steel frame column 20 and the fender 30 is P, the steel frame column 20 is distorted by εf and the fender 30 is distorted by εg with respect to this external force P. .. When the total value of these strains is εh, the relationship between the external force P and the total strain value εh is shown by the curve H in FIG.

In the seismic isolation structure of the present embodiment, first, as shown in FIGS. 2A and 2B, the fender 30 before the displacement of the laminated rubber 16A in the seismic isolation device 16 reaches the allowable displacement at the time of an earthquake. And the reaction force body 40 come into contact with each other. Therefore, the displacement amount of the seismic isolation device 16 can be reduced. In addition, damage to the seismic isolation device 16 can be suppressed.

Next, when the steel support column 20 and the fender 30 receive an external force P from the reaction force body 40 attached to the superstructure 14 moved by the seismic force, as shown by the curves F, G, and H in FIG. When the external force P is 0 or more and less than σ3, both the steel column 20 and the fender 30 are deformed and absorb the seismic energy.

Further, until the external force P becomes σ3 or more and less than σ1, the fender 30 breaks and the seismic energy is absorbed by the elastic deformation of the steel frame column 20.

Further, when the external force P becomes σ1 or more, the steel frame column 20 yields, and the steel frame column 20 absorbs seismic energy while being plastically deformed. The yield load σ1 of the steel frame column 20 is 1.1 times or less the breaking load σ3 of the fender 30. Therefore, after the fender 30 is broken, the steel frame column 20 is quickly plastically deformed to absorb seismic energy.

The yield load σ1 and the breaking load σ2 of the steel frame column 20 are smaller than the breaking load (load at the time of allowable displacement) of the laminated rubber 16A. Therefore, before the laminated rubber 16A breaks, the energy absorption performance of the fender 30 and the steel frame support 20 can be sufficiently exhibited.

Further, since the steel frame column 20 yields, it is possible to prevent an excessive seismic force from being input to the lower structure 12. As a result, damage to the lower structure 12 can be suppressed.

Further, in the seismic isolation structure according to the present embodiment, the two fenders 30 attached to both flanges 24 of the steel frame column 20 alternately come into contact with the reaction force body 40. Therefore, seismic energy can be absorbed on both sides of the vibration that sways from side to side.

Further, in the seismic isolation structure according to the present embodiment, the fender 30 and the reaction force body 40 are provided so as to face each other not only in the X direction but also in the Y direction. Therefore, even when the lower structure 12 and the upper structure 14 are relatively displaced not only in the X direction but also in the Y direction, the fender 30 comes into contact with the reaction force body 40 and can absorb seismic energy. ..

In the present embodiment, the steel frame support 20 and the fender 30 are installed in the lower structure 12, and the reaction force body 40 is installed in the upper structure 14, but the embodiment of the present invention is not limited to this. do not have. For example, as shown in FIG. 4A, the reaction force body 40 may be installed in the lower structure 12, and the steel frame column 20 and the fender 30 may be installed in the upper structure 14. Even in this way, the effect of reducing the displacement amount of the seismic isolation device 16 and suppressing damage and the effect of absorbing seismic energy by the fender 30 do not change.

Further, in the present embodiment, two fenders 30 are attached to the steel frame column 20, but the embodiment of the present invention is not limited to this. For example, as shown in FIG. 4B, two steel frame columns 20 may be provided on one beam 12B, and only one fender 30 may be attached to each steel frame column 20. By doing so, even when the spans of the beams 12B and 14B are long, damage to the seismic isolation device 16 can be suppressed and seismic energy can be absorbed.

It should be noted that it is not always necessary to provide two steel frame columns 20 to which only one fender 30 is attached on the beam 12B, and only one may be provided. In this case, for example, in a seismic motion that sways from side to side, seismic energy can be absorbed only when the upper structure 14 moves relative to the right side or the left side with respect to the lower structure 12.

Further, in the present embodiment, the fenders 30 and the reaction force bodies 40 facing each other are provided along the X direction and the Y direction, but the embodiment of the present invention is not limited to this, and only in the X direction. , May be provided only in the Y direction.

Further, in the present embodiment, the reaction force body 40 includes a fixing portion 42 integrally formed with the beam 14B and the footing 14D, and a pressing portion 44 protruding downward from the fixing portion 42. The embodiment of the invention is not limited to this.

For example, the reaction force body 40 may not be integrated with the footing 14D but may be integrated with only the beam 14B. In this case, the strength of the reaction force body may be increased by increasing the reinforcement arrangement inside the reaction force body or increasing the volume of the reaction force body. By doing so, the place where the steel frame support 20 is installed can be freely set. Alternatively, the reaction force body 40 may be a steel frame structure using H-shaped steel or the like.

If the distance in the height direction from the slab 12C of the lower structure 12 to the beam 14B of the upper structure 14 is large, the length of the footing 14D in the height direction is increased, and the footing 14D is provided with a fender. The materials 30 may be brought into contact with each other. That is, the footing 14D can also serve as the reaction force body 40.

Further, in the present embodiment, the lower end portion of the steel frame column 20 is embedded in the beam 12B, but the embodiment of the present invention is not limited to this, and a base plate is welded to the lower end portion of the steel frame column 20 to form this base plate. It may be fixed to the beam 12B by using an anchor bolt or the like. By doing so, it is easy to arrange the beam 12B.

Further, in the present embodiment, a fender is used as a cushioning material, but the embodiment of the present invention is not limited to this. For example, coil springs, low yield point steels and the like can be used. By using the coil spring, the input of the seismic force to the seismic isolation device 16 can be reduced by elastically resisting the seismic force. In addition, by using low yield point steel, seismic energy can be absorbed by plastic deformation from the stage where the external force is small.

Further, in the present embodiment, the steel frame strut 20 made of H-shaped steel stiffened by the stiffening plate 26 is used as the strut, but the embodiment of the present invention is not limited to this. For example, the stiffening plate 26 may not be provided, or a square steel pipe may be used instead of the H-shaped steel. Further, the columns are not limited to steel frames, and may be formed of reinforced concrete or the like.

Further, in the present embodiment, the lower structure 12 and the upper structure 14 are made of reinforced concrete, but the embodiment of the present invention is not limited to this, and for example, columns 12A, 14A, beams 12B, 14B are formed of H-shaped steel. , The lower structure 12 and the upper structure 14 may be made of steel. Further, the lower structure 12 and the upper structure 14 may be made of steel-framed reinforced concrete. As described above, the seismic isolation structure according to the present invention can be implemented in various embodiments.

12 Substructure 14 Upper structure 16 Seismic isolation device 20 Steel support (support)
30 Fender (buffer member)
40 reaction force

Claims (4)

Substructure and
The seismic isolation device mounted on the upper part of the lower structure,
The superstructure supported by the seismic isolation device and
A strut that protrudes vertically from one of the substructure or the superstructure and has a cushioning member attached to the side surface.
A reaction force body that protrudes in the vertical direction from the lower structure or the other of the upper structure and is provided so as to face the cushioning member.
Equipped with
A seismic isolation structure in which the horizontal distance between the shock absorber and the reaction force is equal to or less than the allowable displacement of the seismic isolation device, and the breaking load of the shock absorber is smaller than the breaking load of the seismic isolation device. The seismic isolation structure according to claim 1, wherein the cushioning member is attached to both side surfaces of the support column. The seismic isolation structure according to claim 1 or 2, wherein the breaking load of the support column due to bending or shearing is larger than the breaking load of the cushioning member and smaller than the breaking load of the seismic isolation device. The reaction force body is any one of claims 1 to 3, wherein the reaction force body is integrally formed with a beam provided on the lower structure or the other side of the upper structure and a footing for fixing the seismic isolation device. Seismic isolation structure described in.

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