JPH0742408A - Base isolation support for lightweight structure - Google Patents

Abstract

PURPOSE:To obtain a base isolation material having small horizontal rigidity and natural period of large period by stacking ring-shaped steel plates through a plurality of rubber materials which are separately arranged between upper and lower flanges. CONSTITUTION:A plurality of ring-shaped steel plates 3 are stacked between an upper and lower flanges 1 through a plurality of rubber materials 2 which are separately arranged to form a supporting body having small horizontal rigidity and natural period of long period. Next, the supporting body is used as a base isolation material for a small, lightweight structure such as a wooden structure to form a vibration system having a natural vibration period of long period. By this method, base isolation for a small, lightweight structure can be provided.

Description

Detailed Description of the Invention

[0001]

[Field of Industrial Application] The present invention relates to a bearing for forming a system having a long natural period in a lightweight structure such as a wooden structure and a small structure such as a dynamic vibration absorber.

[0002]

2. Description of the Related Art Conventionally, a laminated rubber having an alternating structure of a rubber layer and a steel plate as shown in FIG. 2 has been used.
However, since this structure has large horizontal rigidity, it was mainly limited to seismic isolation of heavy structures. For this reason, as shown in FIG. 3, a columnar body having a hollow interior and only the outer periphery of which is a bearing composed of alternating layers of a rubber body and a steel plate member, has a weight of about 10 ton
It was not enough as a seismic isolation bearing for the following lightweight structures.

[0003]

In a general structure, the degree of force transmitted from the ground during an earthquake is represented by the ratio of the amplitude of the force transmitted from the ground to the amplitude of the seismic force, that is, the transmissibility of vibration. It The transmissibility of vibration is the frequency of seismic force ω,
If the frequency of the vibration system is p, and ω ² / p ² > 2,
It is well known that vibration transmissibility <1. In other words, the natural frequency p of the vibration system is made as small as possible, in other words, the natural period is made large, which leads to the reduction of vibration transmission. Therefore, bearings with low horizontal rigidity are required for seismic isolation of lightweight structures such as wooden buildings.

When a dynamic vibration absorber is applied as a seismic isolation device for a super high-rise building, the super high-rise building has a predominant behavior of bending vibration like a statically indeterminate beam with free ends, and its vibration period is 2 The period is about 5 seconds to 5.0 seconds, which is a long cycle compared to a building considered as a low-rise rigid body. Therefore, in order to keep the vibration cycle of the dynamic vibration absorber to be 2.5 seconds to 5.0 seconds, a bearing with low horizontal rigidity is required.

The present invention has been devised so that a long-period vibration system can be constructed as seen in such an example.

[0006]

A ring-shaped steel plate member is sandwiched between two upper and lower flanges, and a plurality of rubber materials are alternately layered on the plate member to form a bearing.

[0007]

In the bearing of the present invention, horizontal rigidity is provided by the laminated rubber support on the outer periphery.

Since it is the support of a lightweight structure, the vertical axial force can be sufficiently supported by the alternating rubber layers. Since the alternating rubber portions are separately arranged, the horizontal rigidity is small and a support having a long natural period can be formed.

[0009]

EXAMPLE FIG. 1A shows a vertical sectional view of a seismic isolation bearing 7 for a lightweight structure. Between the upper and lower flanges 1, the steel plate member 3
Are arranged at intervals, and a plurality of individual rubber materials 2 are arranged on the circumference of the
To form a bearing. The figure shows a cylindrical bearing, but a prismatic shape is also possible. (B) is AA sectional drawing. FIG. 2 shows a bearing of a conventional heavy structure. Since the entire bearing is composed of alternating steel plates and rubber, it has a large horizontal rigidity and it is difficult to construct a long-period vibration system.

FIG. 3 shows another example of the long-period seismic isolation bearing that has been conventionally used. A ring-shaped steel plate member 3 is formed between the upper and lower flanges 1 in a columnar shape with the rubber material 2 alternately stacked. Even in this example, the horizontal rigidity is still large and about 1
The effect of seismic isolation cannot be exerted on lightweight steel products of 0 ton or less.

FIG. 4 shows an example of seismic isolation of a wooden building 4 using the seismic isolation bearing 7 for a lightweight structure. Since the wooden building 4 is light in weight, it is difficult to make a seismic isolation structure in the laminated rubber bearing as shown in FIGS. 2 and 3 because a long-period vibration system cannot be created. However, the seismic isolation bearing 7 for the lightweight structure of the present invention
By using, it is possible to make seismic isolation structures for general houses.

FIG. 4 shows an example of a dynamic vibration absorber using the seismic isolation bearing 7 for a lightweight structure of the present invention. Since a superhigh-rise building has a long natural vibration period, a vibration control device such as a dynamic vibration absorber having a long natural period of 2.5 seconds to 5.0 seconds may be installed. In this case, the conventional laminated rubber has a large shear rigidity and cannot form a vibration system having a long natural vibration period, but it becomes possible by using the lightweight structure seismic isolation bearing 7 according to the present invention. .

[0013]

The effects of the present invention are as follows.

(A) A support mechanism with a long vibration period can be formed in a small and lightweight structure, which enables seismic isolation even in a small and lightweight building.

(B) Since a vibration system having a long vibration period can be constructed, it is possible to form a support for a vibration control device such as a dynamic vibration absorber for a super high-rise building or the like.

[Brief description of drawings]

FIG. 1A is a vertical sectional view of a seismic isolation bearing for a lightweight structure of the present invention, which is a sectional view taken along line XX of FIG. (B) is an AA sectional view of (a).

FIG. 2 is an elevation view of a conventional laminated rubber bearing.

FIG. 3A is a vertical sectional view of another conventional laminated rubber bearing, which is a sectional view taken along line YY of FIG. 3B. (B) is B- of (a)
It is a B sectional view.

FIG. 4 is an example in which the seismic isolation bearing for a lightweight structure of the present invention is applied to a wooden building.

FIG. 5 is an example in which the seismic isolation bearing for a lightweight structure of the present invention is applied to a super high-rise building.

[Explanation of symbols] 1 ... Flange, 2 ... Laminated rubber, 3 ... Steel plate member, 4 ... Wooden building, 5 ... Super high-rise building, 6
... Additional mass for dynamic vibration absorber, 7 ... Seismic isolation bearing for lightweight structures

Claims (1)

[Claims] 1. A ring-shaped steel plate member (3) is alternately arranged between two upper and lower flanges (1), and a plurality of rubber members (2) are arranged at intervals on the circumference of the plate member (3). Seismic isolation bearing for lightweight structures, characterized by alternating layers.