JPS60223577A - 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 nuclear power plant buildings and the legs of Il beams, and some of them have been put into practical use.

As this type of M-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 0.20 or more, sidesliding of the structure becomes more likely to occur, and since the structure is mainly composed of elastic bodies, the structure is surrounded by a hysteresis curve indicating the absorption of seismic energy. There was also the problem that the area covered was small.

Therefore, in order to solve the above problem and obtain large energy absorption, we proposed a seismic isolation device that combines the above laminated rubber with a soft metal, such as lead, that undergoes plastic deformation when earthquake force is applied. has been done.

However, although such seismic isolation devices increase the ability to absorb seismic energy, when short-period vibrations such as strong winds act on a structure, contrary to an earthquake, the soft metal absorbs a relatively small external force. Because it deforms plastically against
There is a problem that the structure shakes more than expected.

This first invention was made with the intention of solving the above-mentioned problems, and its purpose is to provide a structure with a relatively large ability to absorb earthquake energy and withstand external forces applied from the structure side. The purpose of the present invention is to provide a seismic isolation device having appropriate rigidity.

In order to achieve the above object, the present invention provides a seismic isolation device in which flat elastic sheets and steel sheet sheets are alternately laminated,
A first vibration absorption system that supports vertical loads and elastically deforms in response to horizontal loads is interconnected with a pair of rod-shaped bodies, one end of which is latched to the vibration source and the other end of the structure to be seismically isolated, respectively. It is characterized in that it is also equipped with a second vibration absorption system.

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

1 to 5 show an embodiment of a seismic isolation device according to the present invention.

The seismic isolation device shown in the figure is interposed between an upper structure 1 and a lower structure 2, and is made by alternately laminating flat elastic sheets 3 made of neoprene rubber or the like and steel sheet sheets 4 having almost the same shape. The first plate has flat end plates 5.5 attached to both ends.
The other end C of a pair of rod-like bodies 8, 8, whose one end (B, A>) is locked to each of the upper structure 1 and lower structure 2 with a pin 7.7, is held at approximately 90 degrees. A second vibration absorption system 10 is also provided, which is composed of a steel rod 9 having a rectangular cross section and connected so as to pass through them at an angle of .

In order to support the vertical load of the upper structure 1, the first vibration absorption system 6 is arranged in an appropriate number corresponding to the load, and for the horizontal load (Q), as shown in FIG. It deforms elastically with a predetermined elastic modulus.

On the other hand, the second vibration absorption system 10 has no effect on vertical loads, but exhibits the properties shown in FIG. 3 on horizontal loads (Q).

In other words, the rod-shaped bodies 8, 8 have greater rigidity than the steel rod 9, and hardly deform under the horizontal load (Q), and only the steel rod 9 deforms. This aspect will be explained in detail based on FIG. 4.

The figure schematically shows the second vibration system 10,
When a horizontal load (Q) is applied in the direction of arrow ■ in the same figure (a), the upper structure 1 is applied as shown in the figure (1)).
The end B of the bar 8, which is locked to the side, is displaced laterally by σ and moves to B', and the angle between the bars 8.8 widens from 90 degrees to θ degrees.

Then, a predetermined twist is applied to the steel rod 9 due to this displacement.

In response to this torsion, the steel rod 9 has the elasticity to return to its original state when the horizontal load (Q) is removed, and exceed its yield point, within a certain range as shown in Figure 3. When torsion is applied, it exhibits plastic deformation that remains deformed.

Also, in Fig. 4(a), the horizontal load (Q) is indicated by the arrow ■
When the force is applied in this direction, the rod-shaped body 8 is displaced as shown in (C) in the figure, and exhibits similar deformation properties in this direction as well.

Since the above-mentioned seismic isolation device is equipped with the first and second vibration absorption systems 6.10, the horizontal direction 1f (Q)
The properties shown in FIG. 5 are shown in FIG.

Here, the present inventors set more specific numerical values for the seismic isolation device having the above-mentioned configuration and attempted vibration analysis.

That is, the first vibration absorption system 6 and the second vibration absorption system 10 were each set as follows, and the following results were obtained.

The elastic sheet 3 is a rubber plate, and the steel plate sheet 4 is a thin iron plate.
It has a circular shape of 50 mm, and the stacking height including the pair of end plates 5 is 2.
50 m, m, and the elastic modulus was set at 56 m/ctn.

On the other hand, the steel rod 9, which is the main body of the second vibration absorption system 1o, has a straight length of 16111 m and a length of about 1 oIll.
Using I11 reinforcing bar, torsion stress is 3X103kg/c
d, and its elastic modulus is 9.2 kg/c
m, yield point is 1.3c+ with horizontal load (Q) of 100kg
The measurement f1 was confirmed to be a point that undergoes a deformation of n.

In addition, the vertical load of the superstructure 1 was set to 5 tons, and the above-mentioned setting conditions are based on the assumption of a scaled model of approximately 1/40 of a 4- to 5-story concrete structure. The results shown in Table 1 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 about 30C-1 and a maximum period of 0.1 to 1.0 seconds, and the elongation=8CIll in Table 1 above approximately corresponds to this value.

Even for such a huge earthquake, the natural period of the entire system is 1.
It is as long as 6 seconds, which is much larger than the earthquake period.

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

Furthermore, the damping constant at each displacement is relatively large, which means that the area surrounded by the hysteresis curve shown in FIG. 5 is relatively large, and seismic energy can be effectively absorbed.

Furthermore, external forces such as strong winds applied to the building are received within the elastic range of the steel rods 9, so the structure shakes less than a seismic isolation device using soft metals such as lead. It shows great stiffness (.

FIG. 6 and FIG. 7 show a second embodiment of the present invention, and only the characteristic points thereof will be explained below.

In this embodiment, the pair of steel rods 12, 12 of the second vibration absorption system 10 of the above embodiment are plastically deformed through a predetermined elastic deformation in response to a horizontal load (Q), and each steel rod One end (A, B) of 12, 12 is locked and fixed to the upper structure 1 and lower structure 2 by a block body 11.11, respectively, and the other end C is fixed to a similar block body 11.
They are fixed so that they are perpendicular to each other.

That is, in this embodiment, the steel rod 9 that causes torsional deformation in the above embodiment is replaced with the steel rods 12, 12 that cause bending deformation.
The steel rod 12.12 is replaced with
, (b), and by adding the characteristics of the first vibration absorption system 6, the characteristics shown in FIG. 5 can be obtained as in the first embodiment.

Therefore, in this embodiment as well, the same effects as in the above embodiment can be achieved.

FIG. 8 shows a third embodiment of the present invention, and the feature is that the second vibration absorption system shown in the first or second embodiment is added to the period of the first vibration absorption system 6. It is at the point where eight units of system 10 are installed.

With this configuration, it is possible to extremely effectively deal with earthquakes from the lower structure 2 or external forces from the upper structure 1 that are applied from any direction.

As explained in detail in the examples above, in the seismic isolation device according to the present invention, a deformation property that combines an elastic body and a rod-like body is obtained, so the area surrounded by the hysteresis curve that absorbs earthquake energy is compared. In addition to being able to make the target larger, the period of the system can also be separated from the earthquake period, and problems caused by resonance can be avoided, among other excellent effects.

[Brief explanation of drawings]

FIG. 1 is a side view of the first embodiment of the invention, and FIG. 2 is a side view of the first embodiment of the invention.
Fig. 3 is a characteristic diagram of the second vibration absorption system, Fig. 4 is a diagram showing the displacement mode of the second vibration absorption system, and Fig. 5 is a seismic isolation device of the present invention. FIG. FIG. 6 is an explanatory view of the main part of the second embodiment, and FIG. 7 is a diagram showing a modification of the second vibration absorption system of the same embodiment. FIG. 8 is a schematic explanatory diagram of the third embodiment. 1... Upper structure 2... Lower structure 3.
...Elastic sheet 4... Steel plate sheet 5.
...End plate 6...First vibration absorption system 7
...Bin 8 ... Rod-shaped body 9 ...
...Steel rod 10 that causes torsional deformation...Second vibration absorption system 11...Block body 12...Steel bar that causes bending deformation Patent applicant: Obayashi Co., Ltd. Patent Attorney - Kensuke IroDrawing 1 Drawing 5 Drawing 8

Claims (3)

[Claims] (1) A first vibration absorption system in which flat elastic sheets 1- and steel sheets are alternately laminated to support vertical loads and elastically deform in response to horizontal loads; A seismic isolation device characterized in that it is also equipped with a second vibration absorption system in which the other ends of a pair of rod-shaped bodies that are latched to a structure to be vibrated are interconnected. (2) The rod-shaped body is made of a rigid body that does not deform under horizontal loads, and a torsion steel rod that undergoes a predetermined elastic deformation and plastic deformation under horizontal loads is interposed at the other end connecting part. Characteristic claims l! The seismic isolation device according to item Il. (3) The seismic isolation device according to claim 1, wherein the rod-shaped body is a bent steel rod C which deforms plastically through a predetermined elastic deformation in response to a horizontal load.