JPH10227154A - Vibration-isolation material and vibration isolating structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure sufficient attenuation performance by supporting many rubber particles or sand particles that are adhered with mutual voids interven ing, using asphalt as a binder, beneath a structure or in the ground below it. SOLUTION: It is preferable to support a structure 12 on the ground 14 by placing beneath the structure 12 and to form multiple columnar or cylindrical bodies in the vertical direction. Therefore, individual vibration-isolation material 10 receive greater vertical load per unit area than flat vibration-isolation material, and exhibit better vibration-isolation effect. In such case, the vibration- isolation material 10 is made of many rubber particles that are adhered with voids intervening, using asphalt as a binder, or many rubber particles and many sand particles. And whole or part of the circumferenetial face of each particle is thinly covered, asphalt that binds the particles attenuates earthquake energy inputted into the vibration-isolation material 10 and reduces the input acceleration of the earthquake into the structure 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic isolation material used for seismic isolation of a structure and a seismic isolation structure of the structure.

[0002]

2. Description of the Related Art Conventionally, a seismic isolation material made of sand particles covered with asphalt and a seismic isolation structure in which a large number of sand particles covered with the asphalt are laid directly under a structure to support the structure have been proposed. (Japanese Unexamined Patent Application Publication No. 3-33527).
issue).

[0003]

In the conventional seismic isolation material and the seismic isolation structure using the same, the sand covered with asphalt supports the structure with its rigidity, and the asphalt supports the structure. It has the function of attenuating the seismic energy input to the system.

[0004] By the way, conditions for such a seismic isolation material to exhibit sufficient damping performance are known. That is,
The condition is that the magnitude of the inherent vibration cycle of the seismic isolation material is greater than the magnitude of the vibration cycle of the earthquake input to the seismic isolation material. In this respect, in the conventional seismic isolation material including sand particles and asphalt covering the same, the rigidity thereof is relatively high because most of the seismic isolation material is occupied by sand particles, The magnitude of the natural vibration period of the material is smaller than the vibration period of the earthquake. For this reason, the conventional seismic isolation structure using the seismic isolation material does not exhibit sufficient damping performance.

An object of the present invention is to provide a seismic isolation material and a seismic isolation structure that exhibit more effective damping performance.

[0006]

According to the present invention, there is provided a seismic isolation material comprising:
It includes a large number of rubber particles or a large number of rubber particles and a large number of sand particles bonded to each other with a gap therebetween using asphalt as a binder.

[0007] The seismic isolation material is installed so as to support the structure directly below the structure or in the ground below the structure. In any case, the seismic isolation member may have a flat plate shape, and particularly, the seismic isolation member installed immediately below the structure may include a plurality of cylinders or cylinders.

[0008]

According to the present invention, the asphalt component, which is a binder of a large number of rubber particles in the seismic isolation material, has a function of damping seismic energy. In this seismic isolation material,
Since the asphalt-bonded object is a large number of rubber particles that are elastic, and there is a gap between the large number of rubber particles that allows the movement or deformation of the particles, the rigidity of the asphalt is the same as that of the conventional seismic isolation. Smaller than wood. Also, due to this low rigidity, the magnitude of the natural vibration cycle of the seismic isolation material can be set to be larger than the earthquake cycle. For this reason, in the seismic isolation material of the present invention and the seismic isolation structure using the same, the damping performance of the seismic isolation material is sufficiently and effectively exhibited.

In addition, the seismic isolation material includes a large number of sand particles bonded to each other with a gap between the rubber particles and the asphalt, thereby minimizing the deterioration of the damping performance of the seismic isolation material. In addition, it is possible to increase the rigidity, that is, to increase the supporting force for the structure. As a result, even a heavy structure can be subjected to seismic isolation.

[0010] The seismic isolation material is disposed immediately below the structure,
The structure can be supported on the ground by the seismic isolation material. The seismic isolation member may be a flat plate spread on the ground, but preferably, for example, a plurality of cylinders or cylinders extending in the vertical direction. According to this,
Each of the seismic isolation members receives a greater vertical load per unit area than the above-mentioned plate-shaped one, and exerts a superior seismic isolation effect. Further, when a flat-shaped seismic isolator is placed in the ground below the structure, the seismic isolator is not only the weight of the structure but also the weight of the ground between the structure and the seismic isolator. Therefore, a superior seismic isolation effect is exhibited as compared with a case where the flat seismic isolation member is disposed immediately below a structure.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A seismic isolation material 10 according to the present invention is shown in FIG.
As shown in FIG. 4, it is disposed directly below the structure 12 to directly support the structure 12 such as a building, or as shown in FIG. 5, in the ground 14 below the structure 12. It is arranged, and such an arrangement structure forms a seismic isolation structure for the structure 12.

The seismic isolation member 10 shown in FIGS. 1 and 2 is formed entirely of a box-like body having an open upper end, and the open upper end is open to the ground surface. The structure 12 is received at its bottom in the box-shaped space of the seismic isolation material 10. Seismic isolation material 10
When the ground 14 is of relatively good quality, it can be installed, for example, on the excavated ground, on the split stone 16 (FIG. 1), or directly on the excavated ground (FIG. 3). . When the ground 14 is soft, it is arranged on the ground 17 which has been improved in advance.

The seismic isolation material 10 shown in FIGS.
Has a columnar shape extending in the vertical direction, that is, a columnar shape, and a plurality of them are arranged at intervals in the horizontal direction. Each cylindrical body is in contact with the structure 12 and the ground 14 at both upper and lower end surfaces thereof. Instead of the cylinder, a cylinder (preferably a thick cylinder), a prism, or the like can be used.

Further, the seismic isolation member 10 shown in FIG. 5 is made of a flat plate, that is, a plate extending horizontally.

The seismic isolation material 10 shown in each figure is made of asphalt 1
A large number of rubber particles 22 (see FIG. 6) bonded to each other with a gap 20 using the binder 8 as a binder, or a large number of rubber particles 22 and a large number of sand particles bonded together with a gap 20 using the asphalt 18 as a binder 24.

The asphalt 18 covering the whole or a part of the peripheral surface of each of the particles 22 and 24 and connecting these particles to each other acts to attenuate the seismic energy input to the seismic isolation member 10 during an earthquake. Thereby, the input acceleration of the earthquake to the structure 12 is reduced.

In the seismic isolation member 10 shown in FIG. 6, the rubber particles 22 themselves have elasticity, and the gap between the rubber particles 22 when an external force (seismic force) acts on the seismic isolation member 10 is shown. 20
Has a structure that allows the rubber particles to move or deform, and therefore the rigidity of the seismic isolation member 10 as a whole is relatively small. For this reason, regarding the inherent vibration period of the seismic isolation material 10,
It can be set to be larger than the vibration cycle of the earthquake. Because of this large natural frequency, asphalt 18
Is sufficiently exhibited, and the input acceleration of the earthquake to the structure 12 can be significantly reduced.

The same applies to the seismic isolation member 10 shown in FIG. 7 including the sand particles 24 in addition to the rubber particles 22. The seismic isolation member 10 shown in FIG. 7 has higher rigidity than the seismic isolation member 10 shown in FIG. 6 because the sand particles 24 are an inelastic material. However, this increase in stiffness does not significantly reduce the natural frequency of the seismic isolation material. Due to the presence of the rubber particles 22, the natural frequency is still maintained at a value larger than the frequency of the earthquake. . Seismic isolation material 10 in FIG.
Can be applied to a structure having a weight that is difficult to support with the rigidity of the seismic isolation member 10 of FIG.

The rubber particles 22 have a chip shape or a powder shape. The shapes of the rubber chip and rubber powder are
It can be arbitrarily selected from an elongated one, a round one, a square one, and the like. The rubber particles 22 can be obtained, for example, from waste rubber tires.

The seismic isolation material 10 is a mixture of an asphalt emulsion, a solidifying agent for solidifying the asphalt emulsion (for example, cement or polyurethane resin liquid), and a dispersing agent (used for preventing the solidifying agent from agglomerating). A mixture obtained by adding and mixing a large number of rubber particles to a liquid (for convenience, referred to as “mixture A”), or a mixture obtained by adding and mixing a large number of sand particles to the mixture A (for convenience, “mixture B”)
That. ) Can be obtained by spreading them in a plate shape at an appropriate thickness in the field, or forming them into an appropriate shape at a factory. The seismic isolation material 10 shown in FIGS. 1, 2 and 5 is the former, that is, the one that was constructed on site, and the seismic isolation material 10 shown in FIGS.

An example of the mixture A and the mixture B is shown below.

In the mixture A, the rubber particles are 1.41 to 3.
It is composed of rubber chips having a particle size of 36 mm, the asphalt emulsion is composed of an asphalt emulsion having a base asphalt penetration of 60/80, and the solidifying agent is usually composed of Portland cement. The weight ratio of the components of the mixture A is 4
(Rubber particles): 1.5 (asphalt emulsion): 0.5 (solidifying agent).

The mixture B comprises the same rubber particles, asphalt emulsion and solidifying agent as in the mixture A, and sand particles composed of Toyoura sand. The component weight ratio of mixture B is
4 (rubber particles): 1.5 (asphalt emulsion): 0.5 (solidifying agent): 4 (sand particles).

The cement in the mixture reacts with the water in the asphalt emulsion and solidifies, whereby the asphalt emulsion solidifies to form asphalt. The rubber particles, the rubber particles and the sand particles,
And the sand particles are bound by the asphalt. The amount of the asphalt emulsion is smaller than the rubber particles and the sand particles, and the amount is such that the rubber particles and the sand particles are filled between the rubber particles and the sand particles, and between the sand particles. Not quantity. That is, the amount of the asphalt is an amount such that the whole or a part of the surface of the rubber particles and the sand particles is covered thinly. For this reason, voids are generated between the particles bonded to each other.

A cylinder (diameter) obtained by molding the mixture A
50 mm and a height of 100 mm) and a cylindrical body (diameter of 50 mm and a height of 100 mm) obtained by molding the mixture B were respectively installed in a vibration triaxial testing apparatus, and a lateral pressure applied to a test body composed of the cylindrical body was measured. Was kept constant and the axial pressure on the test piece was varied, and the test results as shown in FIG. 8 were obtained. According to the test results, the seismic isolation material according to the present invention
It can be seen that both of the mixture A and the mixture B exhibit a relatively high damping effect from a region of relatively small strain.

The degree of solidification of the asphalt emulsion depends on the amount of the cement mixed. That is, as the amount of the cement mixed increases, the hardness when the asphalt emulsion is solidified, that is, the hardness of the asphalt increases, and the damping ability of the asphalt decreases. Therefore, the mixing amount of the cement is set in consideration of the damping ability of the asphalt. Further, when the weight of the sand particles increases, the effect of reducing the rigidity of the seismic isolation material by the rubber particles is reduced. In view of this, it is desirable that the amount of the sand particles be equal to or less than the weight of the rubber particles in terms of weight ratio. However, the damping ability of the asphalt does not decrease by increasing the amount of the sand particles.

The seismic isolation material 10 of the present invention has a greater seismic isolation effect, that is, the above-described damping effect, as the vertical load applied to the seismic isolation material 10 is larger, and the vibration period of the seismic isolation material 10 accompanying the earthquake input to the seismic isolation material 10 Prolonged operation is exhibited.

The seismic isolation member 10 shown in FIGS. 3 and 5 is arranged in consideration of this. That is, in the example shown in FIG. 3, the individual seismic isolation members receive a larger vertical load per unit area than in the example shown in FIG. 1, and in the example shown in FIG. The seismic isolation member 10 receives a larger vertical load than the example shown in FIG.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an arrangement state of a seismic isolation material of the present invention and an example of a seismic isolation structure.

FIG. 2 is a schematic view showing another example of the arrangement of the seismic isolation material and the seismic isolation structure of the present invention.

FIG. 3 is a schematic view showing still another example of an arrangement state of a seismic isolation material and a seismic isolation structure of the present invention.

FIG. 4 is a schematic view showing an example of the arrangement of a plurality of seismic isolation members shown in FIG.

FIG. 5 is a schematic view showing still another example of an arrangement state of a seismic isolation member and a seismic isolation structure of the present invention.

FIG. 6 is a schematic view showing the structure of a seismic isolation material.

FIG. 7 is a schematic view showing the structure of another example of the seismic isolation material.

FIG. 8 is a graph showing the results of a rigidity test of a seismic isolation material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Seismic isolation material 12 Structure 14 Ground 18 Asphalt 20 Void 22 Rubber particles 24 Sand particles

Claims (9)

[Claims] 1. A seismic isolation material installed under a structure,
A seismic isolation material containing a large number of rubber particles that are bonded to each other with an air gap using asphalt as a binder. 2. The seismic isolation material according to claim 1, further comprising a large number of sand particles, wherein the rubber particles and the sand particles are bonded to each other with a gap therebetween using the asphalt as a binder. 3. A seismic isolation material installed immediately below a structure and supporting the structure, wherein the seismic isolation material includes a large number of rubber particles adhered to each other with an air gap using asphalt as a binder. Seismic structure. 4. The seismic isolation material according to claim 3, wherein the seismic isolation material further includes a large number of sand particles, and the rubber particles and the sand particles are bonded to each other with the asphalt as a binder with a gap therebetween. Construction. 5. A seismic isolation structure including a seismic isolation material installed in the ground below a structure, wherein the seismic isolation material includes a large number of rubber particles bonded to each other with a gap using asphalt as a binder. . 6. The seismic isolation material further includes a number of sand particles, and the rubber particles and the sand particles are bonded to each other with a gap using the asphalt as a binder.
The seismic isolation structure according to claim 5. 7. The seismic isolation structure according to claim 3, wherein the seismic isolation member is formed of a flat plate. 8. The seismic isolation structure according to claim 3, wherein the seismic isolation member is composed of a plurality of cylinders arranged at intervals in the horizontal direction. 9. The seismic isolation structure according to claim 3, wherein the seismic isolation member is composed of a plurality of cylinders arranged at intervals in a horizontal direction.