JPH09133181A - Variable damping type base isolation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure a variable damping capacity by filling up a granular material and a liquid in a tubular hole made in a part on a plane of laminated rubber consisting of a steel plate and rubber and then closing it hermetically, while forming a column of the granular material and the liquid in the laminated rubber inside. SOLUTION: A granular material and a liquid 4 are filled up in a tubular hole made in a part on a plane of laminated rubber 1 and closed hermetically, forming a column 2. When a deformation in this laminated rubber 1 is small, shearing force is handed over among grains with contact of granular material grains themselves, whereby the column 2 obtains increased damping force along with being deformed. When this deformation slightly grows larger, the column 2 receives some external force, and the liquid is taken into a grain pore and then grains become hardened. At this time, pressure is produced in the liquid existing in the grain pore, and contact force among grains grows larger, so the column 2 shows yet larger damping force. At the time of a large earthquake, grains are floated up and liquefied, losing its shearing resistance, and the damping force is gradually decreased, dwindling away into nothing. If a main motion of the earthquake is over, the laminated rubber 1 is restored to its original state before deformation, and the column 2 shows its damping force into full play, and thus any quake in a super-structure after the earthquake is controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic isolation device using laminated rubber in which the damping force changes depending on the degree of deformation.

[0002]

2. Description of the Related Art A damping device is also used in a laminated rubber bearing for the purpose of suppressing swinging of the superstructure supported by the laminated rubber bearing during displacement.

The damping performance of the damping device is required to suppress an increase in displacement of the superstructure during a small earthquake or after the completion of a main motion during a large earthquake. When it becomes large, the damping force acts to suppress the deformation capacity of the laminated rubber bearing, so it is better not to exert it in order to reduce the input of seismic force to the superstructure.

As described above, since the performance required of the damping device varies depending on the scale of the earthquake, in order to maintain the safety of the superstructure against earthquakes of any scale, a plurality of damping devices having different damping forces are combined. However, the damping mechanism becomes complicated and the cost required for it increases.

The lead-containing laminated rubber in which lead is enclosed in the center of the laminated rubber and the high-damped laminated rubber in which the high-damping rubber is used as the rubber have the advantage of not requiring a damping device because the bearing itself has damping performance. Since the damping force is constant, it remains effective only for earthquakes of a specific scale.

The present invention has been made by paying attention to the performance required of a damping device according to the scale of an earthquake, and proposes a seismic isolation device in which a laminated rubber bearing itself is provided with variable damping performance.

[0007]

According to the present invention, a cylindrical hole is formed in a part of a plane of a laminated rubber, and the hole is filled with a granular material and a liquid to seal the laminated rubber. The property of forming a column of liquid and changing the state of granular material existing in the liquid depending on the degree of external force (dilatancy phenomenon and liquefaction phenomenon)
By utilizing the, the damping force exerted by the granular material is changed according to the degree of deformation of the laminated rubber, and the spring bearing of the laminated rubber also has the function of the variable damping device.

While the laminated rubber is deformed, that is, the displacement of the upper structure is small, the shearing force is transferred between the particles due to the contact between the particles of the granular material, so that the granular material and the liquid column are as shown in FIG. It exhibits a damping force that increases with deformation.

When the deformation becomes slightly large, an external force is applied to the granular body and the column of the liquid, so that the liquid is taken into the gap between the particles of the granular body and the dilatancy phenomenon in which the particles are solidified occurs. At this time, pressure is generated in the liquid existing in the space between the particles, and the contact force between particles increases due to this pressure, so that the column of the granular material and the liquid column exerts a larger damping force as shown in FIG.

In the event of a large earthquake that further increases deformation,
Since the particles of the granular material float and liquefy, and the shear resistance is completely lost, the damping force exerted by the granular material and the column of the liquid gradually decreases and disappears as shown in FIG.

When the main motion of the earthquake is completed, the liquefied granular particles rapidly settle and return to the state before the laminated rubber was deformed. It exerts the same damping force as and suppresses the shaking of the superstructure after the earthquake.

Since the granular body and the liquid column exert a damping force from a small-scale earthquake to a medium-scale earthquake and do not exhibit a damping force at the time of a large earthquake, they satisfy the function required for the damping device described above, and the granular body The seismic isolation device with a built-in liquid column has the function of maintaining the safety of the superstructure against earthquakes of any size, while maintaining the deformability as a spring bearing.
As a result, it is not necessary to use the damping device together with the seismic isolation device, and the problem associated with using the damping device together is solved.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The seismic isolation device of the present invention is shown in FIGS.
As shown in FIG. 3, by filling a granular hole and a liquid 4 in a cylindrical hole formed in a part of the plane of the laminated rubber 1 and sealing the same, the damping force changes according to the degree of deformation. The liquid column 2 is formed in the laminated rubber 1, and the spring bearing also has the function of the variable damping device.

The column 2 is formed by directly filling the pores of the laminated rubber 1 with the granular material and the liquid 4 and sealing the upper and lower ends, or a cylindrical body 3 having a horizontal rigidity equal to or less than that of the laminated rubber 1.
It is formed by filling a granular material and the liquid 4 into the inside of the container and sealing it. In the latter case, the pillar 2 is inserted into the hole of the laminated rubber 1.

As shown in FIG. 1, when the column 2 has a height that extends over the entire height of the laminated rubber 1, the upper and lower ends are aligned with the upper and lower ends of the laminated rubber 1, but the height of the column 2 is the laminated rubber 1. If the height is less than the total height of the laminated rubber 1, the pillars 2 are arranged in the laminated rubber 1 at the middle portion in the height direction of the laminated rubber 1, or aligned with the upper end and the lower end. Flange 5 fixed to the upper structure and the lower structure is joined to the upper and lower ends of the laminated rubber 1.

When the laminated rubber 1 is deformed, the pillar 2 is deformed accordingly, and the damping force is changed according to the degree of deformation as shown in FIG.

In the drawing, the case where the cylindrical pillars 2 are formed evenly around the center of the laminated rubber 1 on the plane and around it is shown. The number of the pillars 2, the cross-sectional shape, the cross-sectional area, the height, and the material of the granular material. , Details such as shape and physical properties of liquid are designed separately according to the damping performance to be set. It is preferable that the grain shapes of the granules are as uniform as possible.

[0018]

EFFECTS OF THE INVENTION By filling a granular material and a liquid in a cylindrical hole formed in a part of a plane of a laminated rubber and sealing the same,
Since the granular body and the liquid column whose damping force is changed according to the external force are formed, the damping force as the seismic isolation device can be changed according to the deformation of the laminated rubber.

Since the granular body and the liquid column exert a damping force from a small-scale earthquake to a medium-scale earthquake and do not exhibit a damping force at the time of a large earthquake, the seismic isolation device maintains the deformability as a spring bearing, The granular and liquid columns alone have the function of maintaining the safety of the superstructure against earthquakes of all sizes, eliminating the need for a damping device and eliminating the problems associated with a damping device. It

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing a seismic isolation device.

FIG. 2 is a cross-sectional view of FIG.

FIG. 3 is a graph showing the relationship between the deformation of the seismic isolation device and the damping force.

[Explanation of symbols]

1 ... Laminated rubber, 2 ... Granular body and liquid column, 3 ... Cylindrical body, 4 ... Granular body and liquid, 5 ... Flange.

Claims (1)

[Claims] 1. A granular hole and a liquid are filled in a cylindrical hole formed in a part of a plane of a laminated rubber made of a steel plate and a rubber and sealed, and a column of the granular body and a liquid is provided inside the laminated rubber. A variable damping seismic isolation device that has been formed.