JPS60223576A - Earthquake dampening apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a seismic isolation device.

Conventionally, various proposals have been made as seismic isolation devices for heavy structures such as the legs of IIM and M beams of nuclear power plants, and some of them have been put into practical use.

As this type of seismic isolation device, one using flat laminated rubber is well known, but it has the following drawbacks.

In other words, when the input seismic acceleration becomes large, for example 0.2a or more, the structure is more likely to skid, and since the structure is mainly composed of elastic bodies, the history curve showing the absorption of seismic energy will change. There was a problem that the area surrounded by °C was also small.

Therefore, in order to solve the above problem and obtain large energy absorption, a seismic isolation device has been proposed in which the VA layer rubber is combined with a soft metal, such as lead, that immediately covers the plastic deformation when earthquake force is applied. ing.

However, although such seismic isolation devices increase the ability to absorb seismic energy, when short-period vibrations such as strong J11 act on a structure, contrary to an earthquake, the soft metal is relatively small. Because the structure deforms plastically in response to external forces, there is a problem in that the structure shakes more than expected.

This invention was made with the intention of solving the above-mentioned problems, and its purpose is to have a relatively large ability to absorb earthquake energy, and to be resistant to external forces applied by animals. The purpose is to provide a seismic isolation device with appropriate rigidity.

In order to achieve the above object-4, the present invention provides an elastic body that supports a vertical load and undergoes C-elastic deformation in response to a horizontal load, and a rod-shaped body that undergoes a predetermined elastic deformation and then plastic deformation in response to a horizontal load. (It is characterized by the establishment of Jl.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

1 to 4 show an embodiment of a seismic isolation device according to the present invention.

The seismic isolation device is installed on the upper part 113i of the building vIJ structure, etc. tio
and an elastic body 14 that is interposed between the foundation structure 12 and supports vertical loads and deforms elastically in response to horizontal loads, and a rod-shaped body 16 that deforms plastically through a predetermined elastic deformation in response to horizontal loads.
It is composed of.

The elastic body 14 is made by alternately laminating an elastic sheet 14a made of neoprene rubber or the like in a flat plate shape and a metal sheet 14b made of metal in the same shape with an adhesive interposed therebetween. Flat end plate 14G, 1
4C (configured as J, each end plate 14c, 1
4c is fixed to the superstructure 10 and the foundation f3 structure 12, respectively.

This elastic body 14 exhibits a deformation (σ) property as schematically shown in FIG. 2 with respect to the horizontal direction 1 (Q).

The rod-shaped body 16 is specifically a steel rod with a circular cross section, and has a recess 18 facing the upper structure 10 and the foundation structure 12.
．． 18 is formed, and the upper and lower ends of the rod-shaped body 16 are loosely fitted into this recess 18°18, in consideration of the possibility of replacing the rod-shaped body 16.

This rod-shaped body 16 is approximately the third
As shown in the figure, the material reaches a yield point (Pi) through a predetermined elastic deformation region (A), and thereafter exhibits deformation (σ) characteristics in a plastic deformation region (B).

Here, it is preferable to set the yield point (Pi) to be about 1/4 of the maximum horizontal load (Q).More specifically, the largest earthquake currently expected is , since the horizontal displacement is thought to be about 30 cm,
The yield point (Pi) is set at approximately 7°5 cm.

And above)! Is the seismic isolation VT position horizontal with an i configuration? iXi
The deformation property with respect to the weight becomes a substantially parallelogram-shaped circumferential curve as shown by the solid line C1 in FIG.

In other words, the seismic isolation device has a property that is the sum of the property curve of the elastic body 14 shown by the Ichimori chain line in the figure and the property curve of the rod-shaped body 16 shown by the dotted line.

The present inventors set a specific reduced model of the seismic isolation device described above as follows and attempted C vibration analysis.

As the elastic body 14, a disc-shaped rubber sheet with a diameter of 150+nm and a steel plate are laminated to approximately 250 IR #l, and the elastic modulus is set to 50 kg/Cl11, and the rod-shaped body 16 is formed with a C diameter of 13 Il1 m. , its length is about 50
A steel bar called the so-called PC steel bar C type No.
It was set to m.

J3, the elastic modulus of the above steel bar is 112 kg/Cl1l, and the yield point is the point at which it deforms by 1.8 cm under a horizontal load of 200 kg.

In addition, the lead white load is 5tOn, and each of these values is 4~
This corresponds to approximately 1,740 = 1 concrete structure with 5 floors.

Based on the settings of the above article f1, the analysis results shown in Table 1 below were obtained.

Table 1 Keq････････････････････････････････････････････････････････････････････････････････････････････････････････････････････････････････Table 1 Keq･･･････････････････････････････････････････････････････････････････････････････』
...... Damping constant of seismic isolation device From the above results, the seismic isolation device of the present invention provides the following effects.

That is, the currently assumed huge earthquake has a horizontal displacement of approximately 30 cm and a maximum period of 0.1 to 1.0 seconds, and σ=f3 am in Table 1 above approximately corresponds to this value.

Even for such a giant earthquake, the natural period of the entire system is 1.
It is long at 6 seconds, and is much more appealing than the earthquake period.

Therefore, it is possible to prevent the amplitude from increasing due to resonance with the earthquake cycle.

In addition, the damping constant for each displacement is relatively large, effectively absorbing seismic energy.

Furthermore, against external forces such as strong pressure applied to the building eI,
Since this is received within the elastic region of the rod-shaped body 16, the structure exhibits less shaking and relatively high rigidity than a seismic isolation device using a soft metal such as lead.

FIG. 5 is a schematic diagram showing another embodiment of the present invention, and only its features will be described.

In this embodiment, the rod-shaped body 16 is bent into a substantially S-shape and is installed together with the elastic body 14 between the upper structure 10 and the foundation structure 12. The end portions are fixed to the side surfaces of the base structure 12 and the base structure 12, respectively.

Even with the 1c device configured in this way, the seismic isolation device has the characteristics shown in FIG.

Vibration analysis was also performed on the seismic isolation device of this structure under the model conditions shown below.

In other words, the elastic body 14 and the upper part, the foundation 4i structure 10.1
The distance between the two and the vertical load are set to the same values as in the above embodiment, and the diameter of the S-shaped rod 16 is 22111111.
The steel rods were set to be bent at the same curvature so that the length was 300 mm.

Table 2 below shows the results of analysis under the above conditions.

Table 2 In addition, the elastic modulus of the S-shaped bar 6 marked in 1- is 87°2
kg/cm1 The yield point is σ= with a horizontal load of 200 kg.
There was a point e with 2°3cIR.

Although the results in Table 2 above are slightly different from those in Table 1 above, T (period of the entire system) and l+eq (damping constant) have similar trends, and the same effect as in the above example can be obtained. It will be done.

In each of the above-mentioned embodiments, the case where a single rod-shaped body 16 is used is shown as an example, but a plurality of rod-shaped bodies 16 may be loosely bundled with a string or the like and used.

Further, the bent shape of the rod-shaped body 16 in the second embodiment may be not only an S-shape but also a U-shape.

As explained in detail in the embodiments above, in the seismic isolation device according to the present invention, since the deformation property of the combination of the elastic body and the rod-like body is reduced, the Not only can the area be made relatively large, but the period of the system can also be separated from the earthquake period, and various excellent effects can be obtained, such as avoiding problems caused by resonance.

[Brief explanation of drawings]

Figure 1 shows the installed state of the seismic isolation device according to Ja Ming, Figure 2 is a characteristic diagram of the elastic body, Figure 3 is a characteristic diagram of the rod-shaped body,
FIG. 11 is a characteristic diagram of the seismic isolation device, and FIG. 5 is a schematic diagram of another embodiment. 10... Upper structure 12... Basic structure 14... Elastic body 16... Rod-shaped body 18
... Four Patent Applicants: Obayashi Co., Ltd. Attorney - Color 11! t1

Claims (4)

[Claims] (1) Supports vertical carts and prevents elastic deformation from horizontal loads.
A seismic isolation device comprising an elastic body that deforms plastically through a predetermined elastic deformation in response to a horizontal load. (2) The seismic isolation device 0 according to claim 1, wherein the elastic body is formed by laminating an elastic material made of a polymer and a metal plate in an intersecting U pattern. (3) The seismic isolation device according to claim 1, wherein the rod-shaped body is made of a steel rod having a relatively small diameter. (4) The seismic isolation device according to claim 3, wherein the steel rod is bent into a substantially S-shape or U-shape.