JP2002147527A - Laminated rubber for base isolation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of breakage or crack on an end part of a cover rubber as well as adhesion peeling accompanied by stress concentration at large deformation and remarkably improve base isolation performance and duration life. SOLUTION: In this laminated rubber for base isolation, a whole around of an outer periphery of a laminated body 3 comprising a hard plate 1 and a rubber like elastic plate 2 is covered with a cover rubber 4, and flanges 5A and 5B are adhered and fixed on both ends thereof along a laminating direction. Step parts 6A and 6B are formed on the flanges 5A and 5B and central parts 5a1 and 5b1 thereof are protruded to the laminated body 3 side. On both end parts of the cover rubber 4, step rubber end parts 4a1 and 4b1 having almost a same step difference h1 with a step difference h of the step parts 6A and 6B, and curved surface rubber parts 4a2 and 4b2 constituted by continuously forming curved surfaces R and R1 in two steps of which outer surface curves inwardly in a shape of a longitudinally sectional arc so that the cross sectional area becomes larger approaching nearer to the rubber end parts 4a1 and 4b1 are integrally formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated rubber for seismic isolation, and more particularly, to a laminated body in which a plurality of hard plates and rubber-like elastic plates are alternately laminated, and the entire outer peripheral portion has a cylindrical shape. It is covered with covering rubber, and mounting flanges are adhesively fixed to both ends of the laminate in the laminating direction, so that upper structures such as buildings and bridges can be horizontally mounted on lower structures such as foundations and piers. It is used to support swinging displacement and to prevent damage to the upper structure by reducing the acceleration of vibration input by an earthquake etc. under conditions where vertical load due to the weight of the upper structure is acting. Related to seismic isolation laminated rubber.

[0002]

2. Description of the Related Art This type of rubber bearing for seismic isolation is interposed between an upper structure and a lower structure, and normally functions to transmit the weight of the upper structure to the lower structure and support it. For this reason, once installed, it is very difficult to replace it technically and economically. Therefore, the seismic isolation laminated rubber is required to have the same durable life as the upper structure.

As shown in FIG. 5, this type of laminated rubber for seismic isolation generally comprises a plurality of hard plates 1 such as thin steel plates and rubber-like elastic plates 2 alternately laminated. The entire outer peripheral portion of the laminated body 3 is covered with a cylindrical covering rubber 4 having excellent weather resistance and corrosion resistance, and both ends of the laminated body 3 in the laminating direction, that is, upper and lower ends, are provided with an upper structure. The flanges 5A and 5B for attachment to the body A and the lower structure B are integrally fixed by vulcanization bonding of rubber.

[0004] In the above-mentioned general seismic isolation laminated rubber C, the laminated rubber C is applied in response to vibration input due to an earthquake or the like.
Large shear deformation occurs as a whole, and a large horizontal distortion of several hundred percent acts on the rubber-like elastic plates 2 sandwiched between the hard plates 1. In particular, the rubber-like elastic plates 2 and 2 located at both ends of the laminated body 3 and in contact with the mounting flanges 5A and 5B, and both end portions 4a and 4b of the covering rubber 4 surrounding the outer periphery thereof are one-sided due to shear deformation. Extremely large stress such as tension is applied on the side and compression is applied on the other side, and the adhesive between the laminate 3 and the mounting flanges 5A and 5B is peeled off, thereby causing damage or breakage of the laminated rubber C, resulting in desired durability. There is a problem that the life cannot be obtained.

[0005] As a solution to such a problem, a device disclosed in Japanese Patent Publication No. Hei 7-84814 has been proposed. As shown in FIG. 6, the end portions 4a and 4b of the covering rubber 4 that covers the entire outer peripheral portion of the laminate 3 are in contact with the mounting flanges 5A and 5B.
The outer surface is formed on a curved surface R which is curved in a circular arc shape or a circular arc-like shape with its outer surface facing inward so that the cross-sectional area gradually increases as approaching the flanges 5A and 5B.

[0006]

However, as described above, the end portions 4a and 4b of the covering rubber 4 are formed so that the outer surface thereof has a curved surface R which is warped in an arcuate cross section or an arc-like shape. In the case of conventional laminated rubber for seismic isolation, only the end portions 4a and 4b of the covering rubber 4 are elastically bent and deformed on the curved surface R during the shear deformation of the entire laminated rubber due to an earthquake or the like. , 4b can be reduced, but the coated rubber end portions 4a, 4b,
Since the coating thickness of the bonding portion of 4b with the flanges 5A and 5B is very small, it is inevitable that the adhesive peels off between the coating rubber 4 on the side receiving the tension and the flanges 5A and 5B. Further, at the time of large deformation, deep wrinkles are generated in the rubber end portions 4a and 4b due to bending deformation as shown in FIG. Once cracks and cracks are formed, the cracks and cracks rapidly progress toward the rubber-like elastic plate 2 and lead to damage or breakage of the entire laminated rubber. Therefore, it has been extremely difficult to guarantee the seismic isolation performance and the durable life required for a seismic isolation laminated rubber having a very long use period over a long period of time.

The present invention has been made in view of the above circumstances, and not only prevents the occurrence of adhesive peeling due to stress concentration at the time of large deformation, but also prevents the occurrence of cracks and cracks at the end of the coated rubber. It is an object of the present invention to provide a seismic isolation laminated rubber capable of achieving a significant increase in seismic isolation performance and durability life.

[0008]

In order to achieve the above object, a laminated rubber for seismic isolation according to claim 1 of the present invention is a laminated body in which a plurality of hard plates and rubber-like elastic plates are alternately laminated. The entire area of the outer periphery of is covered with a tubular covering rubber,
A seismic isolation laminated rubber in which flanges are adhesively fixed to both ends in the laminating direction of the laminated body, and both flanges have a step formed so that a central portion thereof projects toward the laminated body side, At both ends in the laminating direction of the covering rubber in contact with the two flanges, a stepped rubber end portion having substantially the same step as the step and surrounding the outer peripheral portion of the central protruding flange portion is provided. The outer surface is formed in a curved surface with a curved surface curved in an arcuate cross section or arc-like shape toward the inside so that the cross-sectional area gradually increases as it approaches the rubber end. It is characterized by having been done.

According to the seismic isolation laminated rubber according to the first aspect of the present invention, the step of the central protruding portion formed on the flange at both ends of the laminated body is provided at both ends of the covering rubber covering the entire outer peripheral portion of the laminated body. By making the same level difference as the step of the part, the both ends of the stepped coated rubber become buffer (cushion) areas for the deformation of the entire laminated rubber, and stress concentrates on the bonding point between the flange and the coated rubber at the time of large deformation It is possible to prevent the occurrence of damage due to adhesive peeling. In addition, a rubber portion having a curved surface whose outer surface is inwardly curved in an arc shape or arc-like shape with an outer surface inward is formed integrally with a rubber end portion having a step which serves as a cushion (cushion) area. By ensuring a large coating thickness of the bonding portion with the flange of the portion, at the time of bending deformation on a curved surface due to large deformation, a deep wrinkle does not occur at the bent portion, thereby receiving repeated deformation. Even so, it is possible to prevent the occurrence of cracks and cracks at the end of the coated rubber, which is the biggest cause of damage and breakage of the laminated rubber, and it is possible to significantly improve the seismic isolation performance and durability life of the entire laminated rubber it can.

[0010] In particular, in the laminated rubber for seismic isolation according to claim 1 of the present invention having the above-described structure, the outer surface of the rubber portion having the curved surface at both ends in the laminating direction of the coated rubber has a circular arc shape with a longitudinally inward section. By forming the curved surface warped in a circular arc-like shape continuously in two steps, at the time of large deformation, in order to bend in the form where the connection top of the two-step curved surface with the largest coating thickness is located at the deepest part, The occurrence of deep wrinkles is completely eliminated, whereby the occurrence of cracks and cracks in the end portions of the coated rubber can be reliably prevented, and the durability life of the entire laminated rubber can be further increased.

[0011] In the laminated rubber for seismic isolation having the above-mentioned configuration, the outer peripheral dimension of the central protruding flange portion of the two flanges is set to be smaller than the outer peripheral dimension of the hard plate constituting the laminated body by a unit thickness of the rubber-like elastic plate. By setting it to be 500% or more, the dependency of the horizontal spring constant of the laminate on the surface pressure can be reduced. That is, when the entire laminated rubber is largely deformed in the horizontal direction under the condition that a large vertical load is applied, the rubber-like elastic plates at both ends in the laminating direction, which are the most deformed among the plurality of rubber-like elastic plates constituting the laminated body, It becomes possible to stop the deformation force acting on the elastic plate to a pure shear deformation force, and thereby, a plurality of hard plates constituting the laminate,
In particular, it is possible to prevent the bending of the outer peripheral end portions of several hard plates located near both end portions in the laminating direction, and to reduce the dependency of the horizontal spring constant on the surface pressure even with a large deformation of 400% or more in horizontal strain. In addition, a predetermined seismic isolation performance can be ensured, and the maximum local distortion generated inside the laminate is reduced, so that the durability life can be further increased.

In the seismic isolation laminated rubber having the above structure, the minimum coating thickness of the rubber portion with a curved surface at both ends in the laminating direction of the covering rubber with respect to the center protruding flange portion is set at the central portion in the laminating direction of the covering rubber. By setting the coating thickness to the same or almost the same as the coating thickness on the hard plate, the protection performance such as weather resistance by the coating rubber is sufficiently ensured, and at the time of large deformation, the rubber part with a curved surface cracks and cracks and it is laminated from there Prevention of damage or breakage of rubber can be prevented, and a predetermined durability life can be ensured.

Furthermore, in the laminated rubber for seismic isolation according to claim 5 of the present invention, the entire outer peripheral portion of the laminated body in which a plurality of hard plates and rubber-like elastic plates are alternately laminated is a tubular covering rubber. A seismic isolation laminated rubber in which flanges are adhered and fixed to both ends in the stacking direction of the laminated body while being covered, and both ends in the stacking direction of the covering rubber in contact with the two flanges are flanged. The outer surface has a curved surface that is curved in an arcuate or arc-like shape in a vertical section inward so as to gradually increase the cross-sectional area as it approaches. .

According to the seismic isolation laminated rubber according to the fifth aspect of the present invention, the outer surface of each of the covering rubbers covering the entire outer peripheral portion of the laminated body has an arc-shaped or arc-like vertical cross section with its outer surface facing inward. The continuous formation of the curved surface having a warped shape in two steps makes it possible to secure a large coating thickness at the bonding portion between the both ends of the coating rubber with the flange and at both ends in the stacking direction of the laminate. For deformation, it is possible to bend and deform with the connection top part of the two-step curved surface as an inflection point, at the time of bending deformation, suppression of adhesion peeling due to stress concentration on the adhesion point between the flange and the covering rubber, and It is possible to prevent the occurrence of wrinkles, thereby preventing the peeling, cracking, and cracking of the end portion of the coated rubber even if it is repeatedly deformed, as in the case of the laminated rubber for seismic isolation according to claim 1. Overall It can be guaranteed over a long period of time seismic isolation performance and durability.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross-sectional structure of the entire seismic isolation laminated rubber according to claims 1 to 4 of the present invention. The seismic isolation laminated rubber C is basically composed of a plurality of hard plates 1 such as a thin steel plate.
And rubber-like elastic plates 2 are alternately laminated.
Is covered with a cylindrical covering rubber 4 having excellent weather resistance and corrosion resistance, and the upper structure A and the lower structure are provided at both ends in the stacking direction of the laminate 3, that is, both upper and lower ends. The flanges 5A and 5B for attachment to the body B are integrally adhered and fixed when the rubber is vulcanized.

Here, as the rubber-like elastic plate 2 constituting the laminated body 3, a natural rubber-based rubber material or a high attenuation rubber material is used, and as the covering rubber 4, natural rubber (NR), SB
A rubber material having excellent weather resistance and chemical resistance such as R, IR, CR, and EPD is used. Further, as the hard plates 1, a hard plastic plate may be used in addition to a metal plate such as a steel plate, an iron plate, an aluminum plate, a copper plate, and a SUS plate. Further, the seismic isolation laminated rubber C is preferably formed in a cylindrical shape so as to be able to cope with swings in all directions in the horizontal direction, but may be formed in a polygonal shape such as a square or a pentagon.

In the laminated rubber C for seismic isolation having the above-described basic structure of the child, the center portions 5a1 and 5b of the mounting flanges 5A and 5B are provided on the mounting flanges 5A and 5B as shown in FIG.
Steps 6A and 6B for projecting 1 toward the laminated body 3 are usually formed to be 3 mm or more. The outer peripheral dimension (outer diameter) D of the center protruding flange portions 5a1 and 5b1 is the outer peripheral dimension (outer diameter) d of the plurality of hard plates 1.
Is set to be 500% or more of the unit thickness t of the rubber-like elastic plates 2.

At both ends in the laminating direction of the cylindrical covering rubber 4, a step between the center projecting flange portions 5 a 1 and 5 b 1 and the outer peripheral flange portions 5 a 2 and 5 b 2, that is, the step portion 6 is formed.
The stepped rubber end portions 4a1 and 4b1 that surround the outer peripheral portions of the central protruding flange portions 5a1 and 5b1 having substantially the same step h1 as the height h of the steps A and 6B, and the stepped rubber end portions 4a1 and 4b1 The curved surface rubber portions 4a2 and 4b2 are formed integrally with the two-stage curved surfaces R1 and R2 whose outer surfaces face inward so as to gradually increase in cross-sectional area as they come closer. Is formed. The minimum coating thickness w of the curved rubber portions 4a2 and 4b2 with respect to the central protruding flange portions 5a1 and 5b1 is equal to or greater than the coating thickness w1 of the hard rubber plate 1 at the center in the stacking direction of the coating rubber 4. Is set.

The laminated rubber C for seismic isolation configured as described above
In the above, at both ends of the covering rubber 4 covering the entire outer peripheral portion of the laminated body 3, a step substantially the same as the step h of the steps 6A, 6B of the central projecting portions 5a1, 5b1 of the mounting flanges 5A, 5B at both ends of the laminated body. h1 having a stepped rubber end portion 4a1,
4b1, the stepped end portions 4a1, 4a
Since b1 serves as a cushion (cushion) area for horizontal deformation of the entire laminated rubber C, stress concentration on a bonding portion between the flanges 5A and 5B and the covering rubber 4 is reduced during a large deformation as shown in FIG. It is possible to prevent the occurrence of damage due to adhesive peeling.

Further, following the stepped rubber end portions 4a1 and 4b1 serving as buffer (cushion) regions, two-stage curved surfaces R, R whose outer surfaces are curved inward in a vertical cross-section arc toward the inside.
The rubber portions 4a2 and 4b2 with curved surfaces formed continuously to 1 are integrally formed to secure a large coating thickness at the end portions of the coating rubber 4, so that the rubber portions with curved surfaces 4a2 and 4a2 with large deformation.
4b2 is a two-step curved surface R, as shown in FIG.
Since the connection top A of R1 is bent and deformed as an inflection point and the connection top A having a large thickness is bent at the deepest portion, deep wrinkles are not generated at the bent portion. As a result, even if repeatedly deformed, no crack or crack occurs at the end of the coated rubber 4 which is the largest cause of damage or breakage of the laminated rubber C, and the seismic isolation performance and the durability life of the entire laminated rubber C are improved. It can be guaranteed for a long time.

In particular, in the seismic isolation laminated rubber C having the above structure,
Center protruding flange portion 5 of both mounting flanges 5A, 5B
Hard plates 1 whose outer diameters D of a1 and 5b1 constitute the laminate 3.
500% of the unit thickness t of the rubbery elastic plate 2 than the outer diameter d of
When the entire laminated rubber C is largely deformed in the horizontal direction under the condition that a large vertical load is applied, the plurality of rubber-like elastic plates 2 constituting the laminated body 3 are set.
.., The deformation forces acting on the rubbery elastic plates 2, 2 at both ends in the laminating direction, which are most greatly deformed, can be stopped to pure shear deformation forces.
, It is possible to prevent bending of the outer peripheral end portions of several hard plates 1 located near both end portions in the laminating direction, and to achieve a horizontal spring constant surface pressure against a large deformation of 400% or more in horizontal strain. Dependency can be reduced and a predetermined seismic isolation performance can be ensured, and the maximum local distortion generated inside the laminate 3 is also reduced, so that the durability life can be further increased.

FIG. 4 shows an enlarged sectional structure of a main part of the laminated rubber for seismic isolation according to claim 5 of the present invention. The basic structure is the same as that shown in FIG. The mounting flanges 5A, 5B at both ends are formed in a flat plate shape over the entire area thereof, and the flanges 5A, 5B are attached to both end portions 4a3, 4b3 of the tubular covering rubber 4 in contact with the flanges 5A, 5B. , The outer surface thereof continuously forms two-step curved surfaces R and R1 that are curved in the shape of a circular arc in the vertical section toward the inside so that the cross-sectional area gradually increases as the distance from the surface increases.

In the laminated rubber C for seismic isolation having the structure as shown in FIG. 4, the outer surface of the rubber cover C covering the entire outer peripheral portion of the laminated body 3 is formed in an arc shape with a vertical cross section at both ends 4a3 and 4b3. Since the two curved curved surfaces R and R1 are continuously formed, the coating thickness of the coating rubber end portions 4a3 and 4b3 with respect to the bonding portions with the flanges 5A and 5B and the coating thickness at both ends in the stacking direction of the laminate 3 is increased. In addition to the above, it is possible to ensure that the connection top A of the two-step curved surface R, R1 is bent in an inflection point for large deformation, so that the connection top A having a large thickness is located at the deepest portion. It is possible to suppress the adhesion peeling due to the concentration of stress on the bonding portion between the flanges 5A and 5B and the coating rubber 4 and also to prevent the occurrence of deep wrinkles at the bending portion.
3A to 3C, even when repeatedly subjected to deformation, the peeling, cracking and cracking of the coated rubber end portions 4a3 and 4b3 are prevented to prevent the occurrence of seismic isolation performance of the entire laminated rubber C. Durable life can be guaranteed for a long time.

In each of the above embodiments, the curved surfaces R,
Although R1 is described as having an arc shape in a vertical cross section, stress concentration and wrinkling due to bending deformation at the time of large deformation such as a shape similar to this, for example, a combination of a plurality of straight lines, or a combination of straight lines and an arc, are given. Any shape can be used as long as the shape can prevent the occurrence of cracks.

[0025]

As described above, according to the first and fifth aspects of the present invention, it is possible not only to prevent or suppress the peeling of the coated rubber due to the stress concentration at the time of large deformation, Because the wrinkled end of the coated rubber that is bent due to large deformation does not need to be deeply wrinkled, cracking or cracking of the coated rubber end which is the largest cause of damage or breakage of the laminated rubber even after repeated deformation over a long period of use. Can be prevented from occurring. Therefore, the seismic isolation performance and the durable life of the entire laminated rubber are remarkably improved, and the required seismic isolation performance and the durable life required for a long period of time, which is equivalent to that of the upper structure, can be guaranteed.

In particular, by adopting the configuration according to the third aspect, bending of the outer peripheral end portions of several hard plates located near both end portions in the laminating direction is prevented, and a large deformation with a horizontal distortion of 400% or more is prevented. In addition to this, it is possible to reduce the dependency of the horizontal spring constant on the surface pressure and secure a predetermined seismic isolation performance, and also reduce the maximum local distortion generated inside the laminate, thereby further improving the durability life.

[Brief description of the drawings]

FIG. 1 is an overall sectional structural view showing an embodiment of a laminated rubber for seismic isolation according to claims 1 to 4 of the present invention.

[Figure 2] Same as above, seismic isolation laminated rubber in normal state (non-deformed state)
FIG. 2 is an enlarged sectional view of a main part at the time of FIG.

FIG. 3 is an enlarged cross-sectional view of a main part in a state where the seismic isolation laminated rubber is largely deformed in the horizontal direction.

FIG. 4 is an enlarged sectional view of a main part showing an embodiment of the laminated rubber for seismic isolation according to claim 5 of the present invention.

FIG. 5 is an overall sectional structural view of a conventional general seismic isolation laminated rubber.

FIG. 6 is an enlarged cross-sectional view of a main part when a conventionally proposed seismic isolation laminated rubber is in a normal state (non-deformed state) in order to solve a problem of a conventional general seismic isolation laminated rubber. FIG.

FIG. 7 is an enlarged cross-sectional view of a main part in a state where the seismic isolation laminated rubber is largely deformed in the horizontal direction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hard board 2 Rubbery elastic board 3 Laminated body 4 Cylindrical covering rubber 4a1, 4b1 Rubber end part with a step 4a2, 4b2 Rubber part with a curved surface 4a3, 4b3 Rubber end part 5A, 5B Mounting flange 5a1, 5b1 Center protruding flange Part 6A, 6B Step C Laminated rubber for seismic isolation R, R1 Curved surface

Claims (5)

[Claims] 1. A laminated body in which a plurality of hard plates and rubber-like elastic plates are alternately laminated is covered with a cylindrical covering rubber over the entire outer periphery thereof, and is provided at both ends in the laminating direction of the laminated body. A seismic isolation laminated rubber having a flange bonded and fixed, wherein both flanges are formed with a stepped portion protruding a central portion thereof toward the laminated body, and the covering rubber contacting with the both flanges is formed as described above. At both ends in the laminating direction, a stepped rubber end portion having substantially the same step as that of the stepped portion and surrounding the outer peripheral portion of the central protruding flange portion, and gradually crossing as approaching these stepped rubber end portions An exemption characterized in that a rubber part with a curved surface is formed integrally with a curved surface whose outer surface is curved in an arcuate or arc-like shape with a vertical cross section facing inward so as to increase the area. Laminated rubber for quake. 2. On the outer surface of the rubber portion with a curved surface at both ends in the laminating direction of the coating rubber, curved surfaces warped in an arc shape or arc-like shape in a vertical cross section are continuously formed inward in two steps. 2. The laminated rubber for seismic isolation according to claim 1, which is formed. 3. The outer peripheral dimension of the centrally protruding flange portion of the two flanges is set to be larger than the outer peripheral dimension of the hard plate constituting the laminated body by 500% or more of the unit thickness of the rubber-like elastic plate. 3. The laminated rubber for seismic isolation according to 1 or 2. 4. The coating thickness of the rubber portion with a curved surface at both ends in the stacking direction of the coated rubber with respect to the center protruding flange portion is the same as or substantially the same as the coating thickness of the coated rubber with respect to the hard plate at the center portion in the stacking direction. The laminated rubber for seismic isolation according to any one of claims 1 to 3, which is set as follows. 5. A laminate in which a plurality of hard plates and rubber-like elastic plates are alternately laminated, the entire outer peripheral portion is covered with a cylindrical covering rubber, and both ends in the laminating direction of the laminate are provided. A seismic isolation laminated rubber in which a flange is bonded and fixed, and the outer surface of the covering rubber in contact with the two flanges has an inner surface on both ends in the laminating direction so that the cross-sectional area gradually increases toward the flange. A laminated rubber for seismic isolation, characterized in that a curved surface warped in a circular arc shape or a circular arc-like shape in a vertical section is formed continuously in two stages.