JPS60168930A - Spring structure - Google Patents

Abstract

PURPOSE:To achieve high deformability while to suppress variation of shearing spring factor of spring structure where circular rubber boards and metal boards are laminated alternatively and integrated by setting the thickness, diameter, total thickness and hardness of rubber board respectively to specific values. CONSTITUTION:Spring structure 3 is constructed by laminating a plurality of metal boards 1 and rubber boards 2 alternatively. Here, the characteristic of spring structure 3 is determined by hardness, resiliency of rubber, ratio D/t between the thickness (t) of single layer of rubber board 2 and the diameter D (primary shape factor), ratio D/h (secondary shape factor) between the total thickness (h) of rubber board 2 and the diameter D, etc. Here, said dimensions are set such that t>=5mm., D/t>=50, D/h<=5, while the hardness of rubber board 2 is set lower than 40. Consequently, high deformability is achieved and a spring having shear spring factor only slightly variable upon variation of vertical load can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a spring structure for supporting a heavy structure with a cushioning effect.

Conventional technology The vibrations applied to buildings when an earthquake occurs can be divided into horizontal motion and vertical motion, but vertical motion has little effect, and it is horizontal acceleration that becomes a problem with the destructive force of an earthquake. When subjected to horizontal acceleration, the building behaves as shown in Figures 1 (a), (b), and (c). <a> is shear deformation where the columns on each floor do not expand or contract; (b) is bending deformation that occurs when the columns on each floor expand or contract;
(C) is rocking that occurs when the ground deforms without the building deforming. The deformation of buildings during actual earthquakes is shown in (a) above.
b) The three types of transformations in (c) occur simultaneously in a combined form,
Among these deformations, rocking poses the greatest destructive force as it may cause the vehicle to fall. If earthquake-resistant design is carried out against the above three types of deformation, especially in the case of high-rise buildings, the earthquake resistance must be increased, making the design difficult and increasing the construction cost.

Therefore, the second method is to reduce the horizontal acceleration applied to the building.
A seismic isolation structure as shown in the figure has been proposed by the present applicant. As shown in Figs. 3 and 4, this is a plurality of spring structures (3) (3) constructed by alternately laminating a plurality of metal plates (1) and a plurality of rubber plates (2). )- is placed between the building (4) and its foundation (5). This spring structure (3) causes elastic deformation only at the thin rubber plate (2) (2L-) between the metal plates (+, ) (1)-.

Since the thickness of each layer of rubber 1 (2) (2) - is small, this spring structure (3) has a large vertical spring stiffness and a small horizontal spring stiffness due to the shear deformation of the rubber, that is, a large vertical loading capacity and a small horizontal spring stiffness. Has spring force.

As a result of characteristic tests on various prototype examples of this spring structure (3), it has been confirmed that the spring ratio of vertical spring stiffness/horizontal spring stiffness can be set to 500 or more by selecting the material and size and shape of the rubber plate. Therefore, by supporting a heavy building with good stability, it is possible to secure it against the ground in the event of an earthquake as shown in Figure 1 (d).
Perform a low-speed sway motion as shown in
By reducing bending deformation and locking, forced deformation of the superstructure can be reduced and safety can be ensured.

By the way, in actual design, the following two conditions are practically required for the spring structure (3).

One is that the amount of horizontal deformation δ shown in FIG. 5 must be large enough to absorb the horizontal movement of an actual earthquake. That is, if the amount of deformation δ is small, the spring structure (3) will not be able to follow the seismic motion and the overturning moment and shear force will become large, making it easy for rocking to occur. In other words, the horizontal deformability δ/h (however, h
A spring structure with a large total thickness of rubber plates is required.

The other one is the horizontal spring coefficient (shear spring coefficient K11)
It is necessary that this does not change with respect to fluctuations in vertical load. Otherwise, it will be difficult to calculate how the building will behave in the event of an actual earthquake, and appropriate structural design will not be possible. Note that the magnitude of the vertical load that the spring structure (3) receives varies greatly depending on the width and height of the building (height of the center of gravity G) shown in FIG. This is because the magnitude of the fluctuation is determined by the rocking and overturning moments.

As described above, the design of the spring structure (3) involves increasing the horizontal deformability δ/h while increasing the shear spring coefficient K of the fluctuating load.
It is important to minimize the influence on 11.

Therefore, the shear spring coefficient K used in the design of conventional spring structures
The following two equations are known as design equations for ll.

■: Compressive load n: Number of rubber plate layers h8: Total rubber thickness Kr: Rotational rigidity (per layer of rubber plate) Ks: Senshinmachi property (per layer of rubber plate) Kl (= (
h/Ac+ h3 /12E I)-'-(21, where h: rubber plate layer thickness E: total elastic modulus of rubber plate A: rubber plate cross-sectional area G: rubber plate shear modulus I: cross-sectional quadratic of rubber plate However, the above equations (1) and (2) express the deformability δ/h
A limit is set for the shear spring coefficient KB within that range.
This formula was developed by researching the following, and it cannot be applied when there are vertical load fluctuations or large horizontal fluctuations that exceed the limits.
It is not effective against earthquake motions in Japan that contain many long-period components (requiring a large horizontal displacement of the spring structure).

Object of the Invention The present invention has been made in view of the above conventional problems and has been improved to provide a spring structure that can obtain a large deformability δ/h and that does not change much in the shear spring coefficient even when the vertical load changes. The purpose is to provide

20 Structure of the Invention The present invention is a product in which circular rubber plates and metal plates are alternately laminated and integrated, and as shown in FIGS. 3 and 4, the thickness of each rubber plate is t, and the rubber plate is When the diameter of D1 is the total thickness of the rubber plate (number of layers nX-t of the rubber plate) is h, t≧
5fi, D/l≧50, D/h≦5, and the hardness of the rubber plate is 40 or less.

E. Example The rubber hardness and shape regulations in the above configuration are based on the properties of the spring structure, the hardness of the rubber, the elastic modulus, the thickness of one layer of the rubber plate,
The ratio of the thickness t of the rubber plate to the diameter D/l (-human shape ratio),
Focusing on the fact that it is determined by the ratio D/h (secondary shape ratio) between the total thickness of the rubber plate and yL)IID, we investigated the range in which the above objective can be achieved through experiments on various prototype examples. This is what I found. Within the above regulations, the combination of rubber hardness and secondary shape ratio D/h is an important element for the above purpose, especially increasing the deformability δ/h, and spring structures with this regulation have not been popular until now. It belongs to the area where it was not. Note that the hardness of rubber commonly used for spring structures is about 50 to 70.

A specific example of a spring structure that satisfies the above-mentioned configuration regulations is shown below.

In other words, the thickness t of the rubber plate is 6fi, and the diameter of the rubber plate is 3.
0 to 40 fi, the total thickness of the rubber plate is 5 to 6 cIm when the diameter is 30, 7 to 8 G when the diameter is 40 cm, the hardness of the rubber is 37, and the thickness of the metal plate sandwiched by the rubber plate is 2 to 6 cIm. 3f
It is l.

In this case, the deformability δ/hX100 can be expected to be approximately 300% in the non-destructive region of the spring structure and approximately 400% in the destructible region.

Note that the failure region is a region in which the spring structure exhibits an effective seismic isolation effect, but the characteristics of the spring change thereafter.

(1) Effects of the Invention The spring structure of the present invention having the above configuration is horizontal. In other words, if the diameter of the rubber plate is 45 cIl, the amount of deformation δ is 30 cm.
, if the diameter is 6 oes, the amount of deformation δ is 40(2). For earthquake motion in Japan, practically 30 (2)
If the amount of deformation δ is secured, a sufficient seismic isolation effect can be expected.
Even if we make a large estimate with some margin, it is considered that the amount of deformation δ should be 40 cm, so a spring structure meeting the above regulations can provide a sufficient seismic isolation effect against a major earthquake in Japan.

Also, the shear spring coefficient K of the spring structure having the above shape restriction
H hardly changes even if the vertical load changes by about twice as much. Therefore, it becomes easy to calculate the behavior of the building when the spring structure is installed under the building as a seismic isolation device, which is extremely advantageous in terms of the structural design of the building.

Note that although the explanation in section 1-2 was made regarding the use of the spring structure as a seismic isolation device for a building, the spring structure of the present invention can be used as a seismic isolation device for heavy structures such as large-scale plants.

[Brief explanation of the drawing]

Figure 1 is a diagram explaining each state in which a building behaves with respect to the ground due to earthquake motion, Figure 2 is a schematic diagram showing a base isolation structure using a nokune structure, and Figure 3 is a front view of a nomane structure. FIG. 4 is a plan view of the spring structure, and FIG. 5 is a front view of the spring structure displaced in the horizontal direction. (1)...Metal plate, (2)...Rubber plate, (3)...Spring structure, (1)...Thickness of rubber plate, (D)...Diameter of rubber plate. Patent Applicant: 1) Hideyoshi, Agent Jianghara Province Hide Agohara *1 Figure C (A) (8) (C) Figure 2 Figure 3 Figure 4B Procedural Amendment February 2, 1980 On the 7th, Mr. Kazuo Wakasugi, Commissioner of the Patent Office. Indication of the case Patent application 2 filed on February 8, 1980, name of the invention Spring structure 3, person making the amendment Relationship to the case Name of patent applicant 1) Eiji 4, Agent 855゜Address Osaka Prefecture 1-15, Edobori, Nishi-ku, Osaka City, Osaka City, Osaka Commercial Evil Area Floor Name (645B) Patent Attorney Ehara Okidai (1 other person) 5.? ! Positive Object Specification 1 Page 3, line 5, "Loading Capacity" is amended to "N Loading Capacity". 2. On page 4, line 4, ``rocking'' is corrected to ``upper l'' and ``S9i''. 3. On page 4, lines 17 to 18, "The size is rocking and" is corrected to "The size is". 4 Correct the ``total elastic modulus'' in the 6th line from directly below the 5th line to the ``star elastic modulus.''

Claims (1)

[Claims] txt In a product in which circular rubber plates and metal plates are laminated alternately and integrated, when the thickness of the rubber plate is t1, the diameter of the rubber plate is D, and the total thickness of the rubber plate is h, t≧5111, D/
l≧50, D/h≦5, and the hardness of the rubber plate is 40
A spring structure characterized by: