JPH09302984A - Three dimensional construction of seismic isolation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide three dimensional construction of seismic isolation without lowering confining efficiency by making use thereof, without confining vertical deformation of the air spring and capable of confining horizontal displacement of the air spring to prevent composite buckling consisting of the air spring and laminated rubber. SOLUTION: This three dimensional construction is so constituted that a seismic isolator consisting of a columnar laminated rubber 12 laminated alternately by rubber elastic plates and reinforced plates and an air spring 14 fixed on the laminated rubber 12 through a holding seat 13 is provided between a main body floor 10 of a structure and a vibration isolation floor 11. In that case, the holding seat 13 and the lower surface of the vibration isolation floor 11 are connected through two approximately horizontal anchor rods 16 at right angles to each other and rubber bushes 17 fixed to both ends of the anchor rod 16 and provided with the horizontal axis at right angles to the anchor rod 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional seismic isolation structure for absorbing both vertical and horizontal vibrations of a building.

[0002]

2. Description of the Related Art A rubber-like elastic plate and a reinforcing plate (for example, a rubber-like elastic plate and a reinforcing plate as a seismic isolation device which is interposed between a main body floor of a structure and a seismic isolation floor above it to absorb and buffer the shaking of an earthquake. It is known that an air spring is superposed on a columnar laminated rubber formed by alternately laminating steel plates) so that horizontal vibration is absorbed by the laminated rubber and vertical vibration is absorbed by the air spring. However, in this device, there is no one that restrains the horizontal displacement of the air spring. Therefore, when a horizontal force acts on the air spring, a horizontal displacement occurs between the upper surface and the lower surface of the air spring. Since the direction of is coincident with the displacement direction of the laminated rubber, the horizontal displacement of the composite system including the laminated rubber and the air spring is increased, and buckling is likely to occur.

In order to solve the above problems, for example, a plurality of guide bushes are fixed to a receiving seat provided between a laminated rubber and an air spring so as to surround the air spring, and air is attached to the lower surface of the base isolation floor. Fix a plurality of guide pins downward so as to surround the spring and insert them vertically into the guide bush, or fix the inner cylinder concentric with the laminated rubber to the receiving seat downward. To fix the outer cylinder surrounding the laminated rubber on the bottom surface of the tremor concentrically with the above inner cylinder, and to make the inner surface of this outer cylinder slidable up and down with respect to the guide shoe fixed to the outer surface of the inner cylinder. In this way, the horizontal displacement of the air spring is restrained.

However, in the former case, a sliding portion is formed between the guide pin and the guide bush, and in the latter case, a sliding portion is formed between the guide shoe on the outer surface of the inner cylinder and the outer cylinder. Since frictional resistance is generated, the vibrational response in the vertical direction is impaired by this frictional resistance, and the sliding part is worn away, which increases the clearance between the sliding parts and reduces the horizontal displacement restraint performance. There was a problem.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a three-dimensional seismic isolation structure in which a seismic isolation device consisting of laminated rubber and an air spring is interposed between a main body floor and a seismic isolation floor. It is possible to prevent buckling of the composite system by restraining, and there is no occurrence of sliding and frictional resistance during the above restraint,
It is intended to provide a three-dimensional seismic isolation structure in which the displacement restraint performance in the horizontal direction does not deteriorate due to use.

[0006]

A three-dimensional seismic isolation device according to the present invention is a columnar laminated rubber in which rubber-like elastic plates and reinforcing plates are alternately laminated and fixed on the laminated rubber via a receiving seat. In a three-dimensional seismic isolation structure in which a seismic isolation device consisting of a compressed air spring is interposed between the main body floor of the structure and the seismic isolation floor above the main body floor, the receiving seat and the bottom surface of the seismic isolation floor are provided. Are connected to each other through two substantially horizontal anchor rods at right angles to each other and a rubber bush fixed to both ends of the anchor rod and having a horizontal axis line orthogonal to the anchor rods.

The laminated rubber described above is an elastic plate made of natural rubber or synthetic rubber such as silicone rubber or ethylene propylene rubber as in the conventional case, and a metal, ceramics or fiber laminated plate (provided that it is impervious to rubber and is impermeable). Of the above), a thermoplastic resin, a thermosetting resin, and a reinforcing plate made of FRP or the like are alternately laminated and joined by vulcanization adhesion to form a columnar shape. Further, the air spring is used by filling high pressure air into a circular bag composed of the natural rubber or synthetic rubber and the fiber reinforcing layer as in the conventional case, and controlling the internal pressure within a predetermined range. It is installed on the laminated rubber via a flat seat.

According to the present invention, the receiving seat is connected to the lower surface of the seismic isolation floor by two anchor rods extending horizontally from the receiving seat in two directions at right angles, thereby restraining the horizontal displacement of the air spring. However, a horizontal rubber bush whose central axis is orthogonal to the anchor rod is provided between the anchor rod and the receiving seat and between the anchor rod and the lower surface of the base isolation floor. Specifically, a support shaft is fitted to the inner surface of the rubber bush and an outer cylinder is fitted to the outer surface, and they are integrated by vulcanization adhesion, and the support shaft is fixed to the anchor rod. May be fixed to the lower surface of the shaft, or the support shaft may be fixed to the lower surface of the seat or the base isolation floor, and the outer cylinder may be fixed to the anchor rod. The anchor rods are installed in at least two directions at 90-degree intervals, but may be provided in four directions of front, rear, left, and right, or may be provided in eight directions at 45-degree intervals.

In order to fix the support shaft to the inner surface of the rubber bush, the support shaft may be directly fixed to the inner surface of the rubber bush by vulcanization bonding, or the inner cylinder may be bonded to the inner surface of the rubber bush by vulcanization bonding. It may be fixed and the spindle may be press-fitted into this inner cylinder. Also,
To fix the outer cylinder of the outer surface of the rubber bush to the lower surface of the seat or seismic isolation floor, fix the above outer cylinder to the lower surface of the seat or seismic isolation floor with a bracket that has a press-fittable hole. it can. In order to fix the outer cylinder to the end of the anchor rod, the press-fittable ring of the outer cylinder can be formed integrally with the end of the anchor rod.

In the three-dimensional seismic isolation structure of the present invention, the horizontal vibration is absorbed by the laminated rubber and the vertical vibration is absorbed by the air spring as in the conventional case. And, even if there is horizontal vibration, since the receiving seat supporting the air spring is connected to the lower surface of the base isolation floor by the anchor rods in two directions at right angles, the magnitude of the horizontal displacement of the base isolation floor with respect to the receiving seat is: It is restricted within the amount of compression of the rubber bush in the radial direction, and does not move so much that buckling occurs in the composite system of the laminated rubber and the air spring. And if the height of the air spring changes due to vertical vibration,
The anchor rod rotates vertically with respect to the axis of the rubber bush, and a shearing force is generated in the rubber bush layer in the circumferential direction.However, since the rubber bush's circumferential modulus is significantly smaller than the internal pressure of the air spring, The vibration response of the air spring is not impaired.

The above rubber bush may be formed in a single layer, or may be formed in a plurality of layers. For example, a rubber bush may be a concentric inner rubber bush and an outer rubber bush.
It has a layered structure, and the inner shaft of the inner rubber bush is fixed to the outer shaft by vulcanization and the first intermediate cylinder is fixed to the outer surface. The inner surface of the outer rubber bush is vulcanized and bonded to the second intermediate cylinder. However, the first intermediate cylinder can be press-fitted into the second intermediate cylinder to integrate them, and in this case, the circumferential strain should be larger than that in the case of a single layer while keeping the compressive strain due to the horizontal force small. You can Then, the first intermediate cylinder and the second intermediate cylinder are squeezed by press-fitting the first intermediate cylinder into the second intermediate cylinder, so that the adhesive strength of the rubber is increased and the durability is improved. The rubber that constitutes the rubber bush may be any rubber that has rubber-like elasticity, such as natural rubber or SB.
Synthetic rubbers such as R, NBR and EPDM are preferable.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 In FIG. 1, 10 is a main body floor of a structure, 11 is a seismic isolation floor, and a columnar laminated rubber 12 made by alternately laminating elastic plates and reinforcing plates is erected on the main body floor 10. An upper surface of an air spring 14 provided on the laminated rubber 12 and fixed via a receiving seat 13 is fixed to a lower surface of the base isolation floor 11 via an upper surface plate 15. As shown in FIG. 2, the receiving seat 13 is a flat plate having a square lower left corner larger than the outer shape of the air spring 14 formed in an arc shape.
The air spring 14 is fixed at a position deviated from the center of the arc toward the arc-shaped corner.

In this embodiment, the right side and the upper side of the receiving seat 13 are orthogonal to the respective sides, and the anchor rods 16 are oriented toward the center lines of the air spring 14 and the laminated rubber 12, and the rubber bushes at both ends of the anchor rods 16. It is connected to the lower surface of the base isolation floor 11 by 17. The anchor rod 16 is integrally provided with forks 16a at both ends. On the other hand, in the rubber bush 17, as shown in FIGS. 3 and 4, a support shaft 18 is fixed to the inner surface and an outer cylinder 19 is fixed to the outer surface by vulcanization adhesion. 18a is connected to the tip of the hawk 16a with a bolt 20.

The seismic isolation floor 11 of the anchor rod 16
The outer cylinder 19 at the side end is the bracket 2 on the lower surface of the seismic isolation floor 11.
The bracket 21 is press-fitted into a hole previously drilled in 1, and the bracket 21 is fixed to the lower surface of the seismic isolation floor 11 with a bolt 22. Further, the outer cylinder 19 at the end of the anchor rod 16 on the side of the receiving seat 13 has the receiving seat 1 via the bracket 21 in the same manner as described above.
3 (see FIGS. 1 and 2). However,
Also, in FIG. 2, the outer cylinder 19 is not shown.

In the above structure, the receiving seat 13 for supporting the air spring 14 includes the horizontal horizontal anchor rod 16 and the support shaft 18, rubber bush 17, outer cylinder 19 and bracket 21 connected to both ends thereof. It is connected to the lower surface of the seismic isolation floor 11 via. Therefore, the horizontal movement of the seat 13 with respect to the base isolation floor 11, that is, the horizontal movement of the air spring 14 is restricted. Moreover, the seat 1 for the seismically isolated floor 11
When 3 is displaced up and down, the outer layer rotates in the circumferential direction with respect to the inner layer of the rubber bush 17, but since the modulus in the circumferential direction of the rubber bush 17 is small, it does not hinder the air spring 14.

Embodiment 2 FIG. 5 shows a rubber bush having a double-layer structure of inner and outer layers. 17A is an inner rubber bush, and 17B is an outer rubber bush. The support shaft 18 is fixed to the inner surface of the inner rubber bush 17A, and the first intermediate cylinder 22A is fixed to the outer surface thereof by vulcanization adhesion. Also, the outer rubber bush 17B
The second intermediate cylinder 22B is fixed to the inner surface of the above and the outer cylinder 19 is fixed to the outer surface thereof by vulcanization adhesion. Then, the first intermediate cylinder 22A is fixed to the second intermediate cylinder 22B by press fitting, and the outer cylinder 19 is fixed to the bracket 21 by press fitting.

Generally, the circumferential strain caused by the rotational force applied to the rubber bushes 17A and 17B in the circumferential direction increases in proportion to the thickness of the rubber bushes 17A and 17B. On the other hand, when the rubber bushes 17A and 17B receive a compressive force in the thickness direction, they try to expand in the axial direction almost in proportion to the thickness, but the rubber slips are restrained at the bonded portions of the inner and outer surfaces of the rubber bushes 17A and 17B. Therefore, the expansion is suppressed and the compression rigidity is increased. Therefore, even if the total thickness of the rubber bushes 17A and 17B becomes larger than that of the rubber bush 17 of the first embodiment, the compressive strain decreases. As the compressive strain decreases, the circumferential modulus decreases and the circumferential strain increases. Therefore, in the second embodiment, the horizontal movement of the air spring 14 is further reduced as compared with the first embodiment, and the air spring 1
4 can be further reduced.

[0018]

EXAMPLE In the first embodiment, the rubber bush 17 has a length of 60 mm, an outer diameter of 106 mm, an inner diameter of 71 mm, and a drawing ratio of 11.5%.
The anchor rods 16 having a distance of 900 mm were fixed to both ends, and the receiving seat 13 and the base isolation floor 11 were connected by the anchor rods 16. The horizontal rigidity per anchor rod was 6,000 kgf / cm, and the vertical rigidity was 1.5 kgf / cm.

On the other hand, the air spring 1 on the receiving seat 13 mentioned above.
4 is a load of 2,500 kgf, an effective diameter of 448 mm, and an internal pressure of 1.
At 6 kgf / cm ² and an internal volume of 22,000 cm ³ , the vertical dynamic spring constant was 405 kgf / cm and the horizontal dynamic spring constant was 150 kgf / cm. Also, the seat 13
The lower laminated rubber 12 is a hollow columnar body having an inner diameter of 140 mm, an outer diameter of 215 mm, and a height of 200 mm, which is obtained by alternately laminating 58 donut-shaped rubber plates and steel plates.
At 00 kgf, the vertical dynamic spring constant is 12,40
At 0 kgf / cm, the dynamic spring constant in the horizontal direction is 50 kgf / cm
Met.

That is, the vertical rigidity of the rubber bush system including the anchor rod 16 is 1/27 of the air spring 14 and 1/8266 of the laminated rubber 12. On the other hand, the horizontal rigidity of the rubber bush system was 40 times that of the air spring 14 and 120 times that of the laminated rubber 12. Therefore, in the vertical vibration, the air spring 14 mainly acts as a base isolation effect, and the influence of the rubber bush system is extremely small. In the horizontal vibration, the laminated rubber 12 is used.
Is the main seismic isolation effect, and the rubber bush system is the air spring 1.
4 horizontal displacement (shift) is prevented.

[0021]

According to the first aspect of the present invention, two anchor rods, which are substantially horizontal to each other and have a receiving seat interposed between a laminated rubber and an air spring and a lower surface of a base isolation floor, and Since it is fixed to both ends of the anchor rod and is connected through rubber bushes having a horizontal axis line orthogonal to the anchor rod, it does not interfere with the seismic isolation of the laminated rubber against horizontal vibration and is accompanied by horizontal vibration. The deformation of the air spring can be restrained to prevent the buckling of the system, and the seismic isolation of the air spring against vertical vibration is not hindered.

According to a second aspect of the present invention, a support shaft is attached to the inner surface of the rubber bush by vulcanization and an outer cylinder is attached to the outer surface thereof, and the rubber bush is attached to the anchor rod via the support shaft, and the outer cylinder is attached. Since they are fixed to the lower surface of the receiving seat or the seismic isolation floor respectively, the connection structure of the rubber bush is simplified.

According to a third aspect of the present invention, the rubber bush has a two-layer structure of an inner rubber bush and an outer rubber bush having different diameters, and a first intermediate cylinder and a second intermediate cylinder are interposed between them. Since the inner rubber bush is vulcanized and adhered to the first intermediate cylinder and the outer rubber bush is vulcanized and adhered to the second intermediate cylinder, the buckling prevention force during horizontal vibration is not reduced, and the air spring during vertical vibration is not reduced. Can be further reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a first embodiment.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an enlarged view of a main part of FIG.

4 is a sectional view taken along line BB of FIG.

FIG. 5 is a vertical sectional view of the second embodiment.

[Explanation of symbols]

10: Main body floor of structure, 11: Seismic isolation floor, 12: Laminated rubber, 13: Seat, 14: Air spring, 16: Anchor rod, 16a: Hawk, 17: Rubber bush, 17A:
Inner rubber bush, 17B: Outer rubber bush, 18:
Support shaft, 19: outer cylinder, 21: bracket, 22A: first intermediate cylinder, 22B: second intermediate cylinder.

Claims (3)

[Claims] 1. A seismic isolation device comprising a columnar laminated rubber formed by alternately laminating rubber-like elastic plates and reinforcing plates and an air spring fixed on the laminated rubber via a receiving seat. In a three-dimensional seismic isolation structure interposed between a floor and a seismic isolation floor above the floor of the main body, two anchor rods that are substantially horizontal to each other and that have the receiving seat and the lower surface of the seismic isolation floor, and A three-dimensional seismic isolation structure, which is fixed to both ends of an anchor rod and is connected through rubber bushes having a horizontal axis line orthogonal to the anchor rod. 2. The three-dimensional seismic isolation device according to claim 1, wherein a support shaft is vulcanized and adhered to the inner surface of the rubber bush and an outer cylinder is adhered to the outer surface thereof, and the rubber bush is anchored via the support shaft. A three-dimensional seismic isolation structure that is fixed to the rod or the bottom of the seismic isolation floor through the outer cylinder. 3. The three-dimensional seismic isolation device according to claim 2, wherein the rubber bush is an inner rubber bush, a first intermediate cylinder adhered to the inner rubber bush, and a first intermediate cylinder is attached to the first intermediate cylinder. 2 intermediate cylinder, an outer rubber bush adhered to the second intermediate cylinder, the inner rubber bush is a support shaft,
A three-dimensional seismic isolation structure in which the outer rubber bushes are vulcanized and bonded to the outer cylinder.