JP6987606B2 - Seismic isolation device and construction method of seismic isolation device - Google Patents

Description

The present invention relates to a seismic isolation device used for a seismic isolation structure of a building such as a building, a detached house, a bridge, or a mechanical device, and more particularly to a slide plate of a seismic isolation device using a sliding bearing.

Conventionally, there has been known a seismic isolation device that reduces the seismic force (impact) transmitted to a building or the like by lengthening a short-period, intense seismic motion when an earthquake occurs. The seismic isolation device is interposed between a building or the like (hereinafter referred to as "superstructure") and a foundation (hereinafter referred to as "substructure") to form a seismic isolation layer. The seismic isolation device supports the superstructure and is equipped with an isolator that slowly displaces the superstructure in the event of an earthquake. Examples of the isolator include laminated rubber, sliding bearings, rolling bearings, and elastic sliding bearings that combine laminated rubber and sliding bearings.

In general, a seismic isolation device to which a sliding bearing is applied to an isolator (hereinafter referred to as "slip bearing type seismic isolation device") is a sliding bearing main body having a sliding material made of a low friction material such as PTFE (tetrafluoroethylene resin). And a sliding plate made of a stainless steel plate that has been surface-treated (for example, polished and / or coated) (for example, Patent Document 1). The bearing body and the sliding plate are arranged so that the sliding material is slidably in contact with the sliding plate. For example, a bearing body is arranged on the lower surface of the upper structure, and a sliding plate is arranged on the lower structure.

When a slip bearing type seismic isolation device is installed, when an earthquake occurs, the superstructure slides on the slide plate via the slide material, and while deforming in the horizontal direction, the slide material slides on the slide plate. The seismic force is absorbed by the frictional force of the moment. As a result, the acceleration of shaking (so-called response acceleration) when the seismic motion acts on the superstructure is a fraction of the acceleration of the seismic motion, so that the superstructure can be protected from the earthquake.

In recent years, as the accumulation of seismic observation records and research on long-period ground motions and earthquakes directly under faults have progressed, it has become necessary to assume larger earthquake motions than before in building design. An increase in the input level of seismic motion leads to an increase in the response deformation (amplitude) of the seismic isolation layer. It is necessary to improve the slip performance (movable range of the superstructure).

In the sliding bearing type seismic isolation device, it is possible to respond to a large earthquake by expanding the size of the sliding plate and expanding the movable range (slip area) of the sliding bearing body.

Further, in Patent Document 1, the slip surface of the slip plate is divided into a plurality of regions, and the first region in order from the center has a friction coefficient (μ1) that does not cause slip against strong winds that frequently occur. In the second region, the friction coefficient is set to μ2, which is lower than μ1, to improve the seismic isolation effect (actively slide), and in the third region, the friction coefficient is higher than μ2 to absorb seismic energy and respond. It is disclosed to suppress deformation (to prevent it from coming off the sliding plate). Further, in Patent Document 1, a fourth region having a higher coefficient of friction (μ4) is formed outside the third region by a coated floor finish such as a resin mortar or a self-leveling floor finish of an epoxy resin. Is disclosed (see FIG. 8).

Japanese Unexamined Patent Publication No. 2005-249103

However, since the sliding plate made of stainless steel plate is a heavy object, there is a problem that increasing the size of the sliding plate leads to an increase in cost in each process of manufacturing, transportation, and construction. At present, when considering the road transportation of the slip plate, the allowable size of the slide plate is about 3000 mm × 3000 mm.

Further, in the seismic isolation device disclosed in Patent Document 1, since the friction coefficient of the third region of the sliding plate is larger than the friction coefficient of the inner second region, when the sliding bearing main body reaches the third region, the superstructure The seismic force acting on the friction will increase not a little. Therefore, an excessive seismic force is applied to the superstructure, and there is a risk that safety in the event of a large earthquake cannot be ensured.

An object of the present invention is applicable to both new construction and seismic retrofitting, and has high seismic isolation performance capable of following a large deformation at the time of a large earthquake while suppressing an increase in cost in each process of manufacturing, transportation, and construction. It is to provide a sliding bearing type seismic isolation device and a construction method of the seismic isolation device.

The seismic isolation device according to the present invention is
A seismic isolation device that is placed between the superstructure and the substructure to support the seismic isolation of the superstructure.
A sliding plate which is fixed to the front Symbol lower structure,
A sliding bearing body that has a sliding material that slidably contacts the sliding plate and is fixed to the superstructure.
A reinforcing plate for supporting the sliding plate and a reinforcing plate are provided.
The sliding plate has a central first region and a second region surrounding the first region and forming an outer edge of the sliding plate .
The first region is joined to the central portion of the main surface of the reinforcing plate.
The second region is made of a resin material, is formed from the peripheral edge of the main surface to the substructure , and has a friction coefficient equal to or lower than that of the first region.
The method of constructing the seismic isolation device according to the present invention is as follows.
It is a construction method of a seismic isolation device that is placed between the superstructure and the substructure and supports the seismic isolation of the superstructure.
The first step of installing a reinforcing plate to which the first region of the sliding plate is joined to the main surface in the substructure, and
A resin material is poured from the peripheral edge of the main surface to the substructure around the first region and cured to form a second region of the slip plate having a friction coefficient equal to or lower than that of the first region. Includes 2 steps.

According to the present invention, it can be applied to both new construction and seismic retrofitting, can suppress an increase in cost in each process of manufacturing, transportation, and construction, and has high seismic isolation performance capable of following a large deformation at the time of a large earthquake. A slip-supporting seismic isolation device can be provided.

FIG. 1 is a diagram schematically showing a seismic isolated building to which the seismic isolation device according to the embodiment of the present invention is applied. FIG. 2 is a perspective view showing the configuration of the seismic isolation device. 3A and 3B are diagrams showing the configuration of the seismic isolation device. FIG. 4 is a diagram showing a configuration of a sliding bearing main body. 5A to 5C are views showing an example of a slide plate construction process. 6A to 6D are diagrams showing the operation of the seismic isolation device. 7A to 7C are diagrams showing the relationship between the load and the displacement of the seismic isolation device. FIG. 8 is a diagram comparing the friction coefficients of the sliding plate according to the embodiment and the sliding plate of the prior art.

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

FIG. 1 is a diagram schematically showing a seismic isolated building A to which a seismic isolated device according to an embodiment of the present invention is applied.

As shown in FIG. 1, the seismic isolated building A has a seismic isolation system 1 as a seismic isolation layer between a building 2 as a superstructure and a foundation 3 as a substructure. Further, a retaining wall 31 is provided around the seismic isolated building A with a gap that allows maximum displacement due to seismic motion.

The seismic isolation system 1 insulates the building 2 from the foundation 3 so that the seismic force is not directly transmitted to the building 2. In addition, the seismic isolation system 1 has a support function that stably supports the building 2, a damping function that absorbs seismic energy to reduce the shaking of the building 2, and a restoration function that restores the horizontal position of the building 2. Have.

The seismic isolation system 1 includes a plurality of first seismic isolation devices 10 and a second seismic isolation device 20. The first seismic isolation device 10 is a sliding bearing type seismic isolation device according to the present invention. The second seismic isolation device 20 is a seismic isolation device other than the sliding bearing type, and may have, for example, a support function, a damping function, and a restoration function such as a laminated rubber bearing, an oil damper, and a steel material. It may not have a support function such as a damper or a lead damper.

FIG. 2 is an external perspective view showing the configuration of the first seismic isolation device 10. FIG. 3A is a plan view of the first seismic isolation device 10. FIG. 3B is a cross-sectional view of the first seismic isolation device 10. FIG. 4 is an enlarged cross-sectional view showing the configuration of the sliding bearing main body 100.

As shown in FIGS. 2, 3A, 3B and 4, the first seismic isolation device 10 is an elastic sliding bearing provided with a sliding bearing main body 100 and a sliding plate 200. The first seismic isolation device 10 has a support function and a damping function. In the present embodiment, the sliding bearing main body 100 is fixed to the building 2 (superstructure), and the sliding plate 200 is fixed to the foundation 3 (substructure).

As shown in FIG. 4, the sliding bearing main body 100 includes a laminated rubber body 110, a sliding material 120, and a flange 130.

The laminated rubber body 110 has a structure in which rubber-like elastic plates 111 (main body rubber) and intermediate steel plates 112 are alternately laminated, and connecting steel plates 113 and 114 are vulcanized and bonded to both upper and lower ends. Further, the laminated rubber body 110 has a protective rubber 115 having excellent weather resistance, which covers the outer peripheral surface of the laminated body (reference numeral omitted) composed of the rubber-like elastic plate 111 and the intermediate steel plate 112. The laminated rubber body 110 is a columnar member having a square columnar shape, a polygonal columnar shape, or a columnar columnar shape. In the present embodiment, the laminated rubber body 110 has a cylindrical shape.

The rubber-like elastic plate 111 is a material containing rubber as a main component, such as natural rubber, isoprene rubber, butadiene rubber, styrene butadiene rubber, ethylene propylene rubber, butyl rubber, halogenated butyl rubber, chloroprene rubber, and a mixed material of rubber and synthetic resin. Is formed by.

The protective rubber 115 may be formed by applying an adhesive to the outer peripheral surface of the laminated body and attaching the protective rubber 115, or may be formed by winding a self-bonding tape made of rubber. Alternatively, the protective rubber 115 may be integrated with the rubber-like elastic plate 111 by simultaneously vulcanizing and molding the rubber-like elastic plate 111 and the rubber material of the protective rubber layer 115.

The sliding material 120 is a plate-shaped member, and is formed of, for example, a fluororesin such as PTFE (polytetrafluoroethylene). The sliding material 120 is fixed to the lower surface (connecting steel plate 114) of the laminated rubber body 110, for example, by adhesion. The sliding material 120 comes into contact with the sliding plate 200 (sliding mating material) when the first seismic isolation device 10 is installed.

The sliding material 120 may be formed in any way as long as it has a small friction coefficient and is suitably slidable when it slides in contact with the sliding plate 200. For example, the sliding material 120 may be a single plate material or may be composed of a plurality of small plate materials. In the present embodiment, the sliding material 120 is composed of a single disk in the shape of a disk. The outer diameter of the sliding material 120 is, for example, 800 mm.

The flange 130 is joined to the upper surface (connecting steel plate 113) of the laminated rubber body 110 by, for example, bolts. The planar shape of the flange 130 may be any shape such as a rectangular shape, a disk shape, an elliptical shape, or a polygonal shape. In this embodiment, the flange 130 has a disk shape.

As shown in FIGS. 3A and 3B, the sliding plate 200 has a shape larger than the outer shape of the sliding bearing body 100. In the present embodiment, the slide plate 200 has a square shape.

The sliding plate 200 has a central first region 210 and a second region 220 surrounding the first region 210. The first region 210 and the second region 220 are made of different materials. The first region 210 and the second region 220 are formed concentrically. The first region 210 and the second region 220 are formed on the reinforcing plate 230. The reinforcing plate 230 ensures the mechanical strength of the sliding plate 200, and can prevent the sliding plate 200 consisting of only the first region 210 before forming the second region 220 from being deformed during transportation and construction. The reinforcing plate 230 has an outer shape equal to or slightly larger than that of the first region 210 for welding and joining with the first region 210 of the sliding plate 200.

The first region 210 is formed of, for example, a metal plate (for example, a stainless steel plate) that has been subjected to surface treatment such as polishing and / or coating. The first region 210 has a shape larger than the outer diameter of the sliding bearing body 100. In the present embodiment, the first region 210 is formed in a square shape. The size of the first region 210 is, for example, 2000 mm × 2000 mm (the same size as the conventional sliding plate). The first region 210 may be formed in a circular shape. The first region 210 is formed in advance on the reinforcing plate 230, and is transported to the construction site in this state.

The second region 220 is made of a resin material such as an epoxy resin and has a friction coefficient equal to or lower than that of the first region 210. The second region 220 is formed in a square shape concentric with the first region 210. The size of the second region 220 is, for example, 5000 mm × 5000 mm. In the sliding plate 200 of the present embodiment, the portion of the second region 220 is enlarged as compared with the conventional sliding plate. The second region 220 is formed, for example, by on-site construction. In the present embodiment, the second region 220 is larger than the reinforcing plate 230 and is also formed on the foundation 3.

It is preferable that the resin material forming the second region 220 has a high self-leveling property in which the surface is formed smoothly with high accuracy just by pouring it. Thereby, the second region 220 can be easily formed by on-site construction.

Further, it is preferable that the resin material has high durability and heat resistance that can withstand repeated sliding at the time of large deformation. As a result, the deformation of the sliding plate 200 when the sliding bearing body 100 (sliding material 120) repeatedly slides on the sliding plate 200 at the time of large deformation can be suppressed, so that the reliability of the first seismic isolation device 10 can be suppressed. Sex improves.

As a resin material having high self-leveling property, durability, and heat resistance, a two-component curable epoxy resin can be applied. For example, Alpha Tech 150 (trade name) or Alpha Tech 180 (trade name) manufactured by Alpha Industry Co., Ltd. is suitable. By using Alpha Tech 150 or Alpha Tech 180, the coefficient of friction of the second region 220 can be equal to or less than the coefficient of friction of the first region 210 made of a metal plate.

It should be noted that the speed of 5 to 400 mm / sec in the horizontal direction with a load of 5 to ^{40 N / mm 2} applied in the vertical direction to the sliding plate manufactured by using the stainless steel plate, Alpha Tech 150, and Alpha Tech 180. It has been confirmed that the friction coefficient of the Alpha Tech 150 and the Alpha Tech 180 is smaller than the friction coefficient of the stainless steel plate by the experiment of repeating the vibration.

The physical property values of Alpha Tech 150 and Alpha Tech 180 are shown in Tables 1 and 2. Table 1 shows the properties in the uncured state, and Table 2 shows the properties in the cured state. As shown in Table 2, the glass transition temperature of a general epoxy resin such as Alphatech 150 is about 50 ° C., whereas the glass transition temperature of Alphatech 180 is 100 ° C., which is extremely high. Therefore, the resistance (heat resistance) to heat generation due to friction when the sliding bearing main body 100 repeatedly slides on the sliding plate 200 is also increased. Therefore, Alphatech 180 is more suitable as the resin material for forming the second region 220 of the sliding plate 200.

The second region 220 is formed, for example, by the steps shown in FIGS. 5A to 5C. That is, first, a formwork corresponding to the second region 220 is installed around the metal plate (first region 210) arranged on the reinforcing plate 230 (see FIG. 5A). In FIG. 5A, the formwork F1 is installed around the foundation 3. Further, in FIG. 5A, a spacer F2 is installed around the metal plate (first region 210) in order to provide a gap 240 between the first region 210 and the second region 220.

Then, the resin material is poured into the mold F1 and filled (see FIG. 5B). At this time, the filling amount of the resin material is adjusted so that the surface of the metal plate (first region 210) and the surface of the resin material (second region 220) are flush with each other. Since the resin material has a high self-leveling property, it spreads uniformly in the mold F1 and the surface becomes smooth with high accuracy. Further, it is also possible to forcibly form a smooth surface by curing the surface of the resin material poured into the formwork F1 with a smooth flat plate at the time of on-site construction.

After the resin material is cured, the mold F1 and the spacer F2 are removed (see FIG. 5C). Further, the peripheral portion of the second region 220 is chamfered. The chamfer size is, for example, 5 mm or less. By the above steps, the second region 220 is formed on the reinforcing plate 230 and the foundation 3 so as to surround the first region 210.

As shown in FIG. 5C, it is preferable that a gap 240 is provided at the boundary between the first region 210 and the second region 220. The width of the gap 240 is preferably, for example, 2 to 8 mm. As shown in FIG. 5A, when forming the second region 220, the gap 240 having a predetermined width can be easily formed by curing the metal plate forming the first region 210 with the spacer F2. As a result, even if the second region 220 is thermally expanded, the boundary portion between the first region 210 and the second region 220 does not bulge, and the smoothness of the slip surface can be maintained. Further, the presence of the gap 240 facilitates the chamfering work of the second region 220. If there is no step at the boundary, the interval 240 may not be provided.

Further, as shown in FIG. 5C, it is preferable that the peripheral edge portion at the boundary between the first region 210 and the second region 220 is chamfered. As a result, when the sliding bearing body 100 repeatedly slides during large deformation, the sliding surface of the sliding material 120 is damaged by the edge of the boundary portion between the first region 210 and the second region 220 of the sliding plate 200. Since it can be prevented, the reliability of the first seismic isolation device 10 is improved. When the resin material is poured into the molds F1 and F2 to form the second region 220, surface tension causes swelling (imaginary line in FIG. 5C) at the edge in contact with the mold F2, but this swelling also occurs due to chamfering. Will be removed. When the gap 240 is provided at the boundary between the first region 210 and the second region 220, the peripheral edge portion of the second region 220 can be easily chamfered.

6A to 6D are diagrams showing the operation of the first seismic isolation device 10. FIG. 6A shows a normal state. FIG. 6B shows a state at the time of small and medium-sized deformation (a state in which only the laminated rubber body 110 is deformed). FIG. 6C shows a state at the time of large deformation. FIG. 6D shows a state in which the first seismic isolation device 10 slides to the second region 220 after further deformation from FIG. 6C.

Normally, as shown in FIG. 6A, the sliding bearing body 100 is located in the first region 210 of the sliding plate 200. When a horizontal seismic force is applied to the building 2, the laminated rubber body 110 of the sliding bearing body 100 is first sheared and deformed in the horizontal direction (see FIG. 6B). Then, when the friction limit is exceeded, slip occurs, and the slip bearing body 100 slides on the first region 210 of the slide plate 200 (see FIG. 6C), and when the deformation further progresses, the second region of the slide plate 200 It slides on the 220 (see FIG. 6D). The sliding bearing body 100 returns to its original position while being damped by the restoring force of the second seismic isolation device 20 (see FIG. 1).

In the first seismic isolation device 10, the sliding plate 200 is much larger than the conventional one and a wide sliding area is secured. Therefore, a huge earthquake that was not expected in the past occurs and the response of the sliding bearing body 100 Even if the displacement becomes large, it can be dealt with.

7A to 7C are diagrams showing the results of simulating the horizontal history characteristics of the seismic isolation system 1 based on the seismic isolation model simulating the seismic isolation system 1. FIG. 7A is a simulation result of the horizontal history characteristic of the first seismic isolation device 10, FIG. 7B is a simulation result of the horizontal history characteristic of the second seismic isolation device 20 (laminated rubber bearing), and FIG. 7C is a seismic isolation device. The simulation result of the horizontal history characteristic of the system 1 (combination of FIG. 7A and FIG. 7B) is shown. 7B and 7C are simulation results based on actual tests, and FIG. 7A is a difference between FIGS. 7B and 7C. In FIGS. 7A and 7C, the case where the friction coefficient of the second region 220 is smaller than the friction coefficient of the first region 210 is shown by a solid line, and the case where the friction coefficient is the same is shown by a broken line.

Specifically, the first seismic isolation device 1 has a sliding plate 200 having a first region 210 (stainless steel rope plate) of 1800 mm × 1800 mm and a second region 220 of 4800 mm × 4800 mm, and a bearing diameter (sliding material 120). In the case where a sliding bearing body 100 with an outer diameter) of 800 mm is provided, a predetermined vibration is applied in the horizontal direction to a seismic isolation model using a 1/10 reduced test piece with a predetermined load applied in the vertical direction. Repeated tests were performed.

As shown in FIGS. 7A and 7C, the horizontal load when the horizontal deformation of the sliding bearing body 100 is the second region 220 is equal to or less than that when the horizontal deformation of the sliding bearing main body 100 is the first region 210. rice field. That is, it was confirmed that the seismic isolation performance was effectively exhibited even in the second region 220 of the slide plate 200. In particular, it was confirmed that by making the friction coefficient of the second region 220 smaller than the friction coefficient of the first region 210, the increase in the horizontal load can be suppressed and the seismic isolation performance is improved.

As described above, the first seismic isolation device 10 (seismic isolation device) according to the present embodiment is arranged between the building 2 (superstructure) and the foundation 3 (substructure) to form the building 2. It is a slip-supporting seismic isolation device that supports seismic isolation. The first seismic isolation device 10 has a sliding plate 200 fixed to the foundation 3, a sliding material 120 slidably abutting the sliding plate 200, and a sliding bearing main body 100 fixed to the building 2. To prepare for. The sliding plate 200 has a central first region 210 and a second region 220 surrounding the first region 210. The second region 220 is made of a resin material and has a friction coefficient equal to or lower than that of the first region 210.

As shown in FIG. 8, in the prior art disclosed in Patent Document 1, the friction coefficient of the resin region formed of the epoxy resin or the like in the sliding plate is larger than the friction coefficient of the metal region formed of the stainless steel plate or the like. Is set to. That is, in Patent Document 1, a resin material having a large coefficient of friction is used in order to suppress excessive displacement due to large deformation that is not the subject of design. On the other hand, in the present embodiment, the friction coefficient of the resin region (second region 220) is equal to or less than the friction coefficient of the metal region (first region 210). That is, the first seismic isolation device 10 of the present embodiment effectively utilizes a resin material having a friction coefficient equal to or less than that of a metal plate such as a stainless steel plate to expand the slip region. It is different from the seismic isolation device disclosed in Patent Document 1, which uses a resin material to suppress excessive displacement.

According to the first seismic isolation device 10, in the sliding plate 200, the second region 220 has a friction coefficient equal to or lower than that of the first region 210, so that the sliding bearing body 100 has the first region 210 and the second region 220. The horizontal force does not increase with the increase of the friction coefficient when passing through the boundary of the first seismic isolation device 10, and it is possible to prevent an excessive force from being applied to the joint portion between the first seismic isolation device 10 and the building 2 or the foundation 3. Therefore, the effect of suppressing the seismic force acting on the building 2 can be stably maintained, and good seismic isolation performance is exhibited.

Further, since the second region 220 is formed of a resin material, it can be easily formed by on-site construction. Therefore, it is possible to realize a large-sized sliding plate 200 without increasing the transportation cost, and the degree of freedom in the dimensional design of the sliding plate 200 is improved. In addition, the area of the sliding plate, that is, the movable range of the sliding bearing body can be easily expanded even for the existing sliding bearing type seismic isolation device. It is possible to realize a seismic isolation structure that can handle large deformations.

In this way, according to the first seismic isolation device 10, it is possible to suppress the cost increase in each process of manufacturing, transportation, and construction, and to realize high seismic isolation performance that can follow the large deformation at the time of a large earthquake. can do.

Although the invention made by the present inventor has been specifically described above based on the embodiment, the present invention is not limited to the above embodiment and can be changed without departing from the gist thereof.

For example, in the first seismic isolation device 10, the sliding bearing body 100 may be fixed to the foundation 3 (substructure), and the sliding plate 200 may be fixed to the building 2 (superstructure).

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Seismic isolation system (seismic isolation layer)
2 Building (superstructure)
3 Foundation (substructure)
10 First seismic isolation device (seismic isolation device)
20 Second seismic isolation device 100 Slip bearing body 110 Laminated rubber body 120 Slip material 130 Flange 200 Slip plate 210 1st area 220 2nd area 230 Reinforcing plate

Claims (7)

A seismic isolation device that is placed between the superstructure and the substructure to support the seismic isolation of the superstructure.
A sliding plate which is fixed to the front Symbol lower structure,
A sliding bearing body that has a sliding material that slidably contacts the sliding plate and is fixed to the superstructure.
A reinforcing plate for supporting the sliding plate and a reinforcing plate are provided.
The sliding plate has a central first region and a second region surrounding the first region and forming an outer edge of the sliding plate .
The first region is joined to the central portion of the main surface of the reinforcing plate.
The seismic isolation device is characterized in that the second region is made of a resin material, is formed from the peripheral edge portion of the main surface to the substructure , and has a friction coefficient equal to or lower than that of the first region. The seismic isolation device according to claim 1, wherein the resin material has a self-leveling property. The seismic isolation device according to claim 1 or 2, wherein the resin material is a two-component curable epoxy resin. The seismic isolation device according to any one of claims 1 to 3, wherein a gap is provided at a boundary between the first region and the second region. Wherein the peripheral edge portion of the first region and boundary of the second region, the seismic isolation device according to any one of claims 1, characterized in that chamfering processing is given 4. The seismic isolation device according to any one of claims 1 to 5, wherein the first region is formed of a stainless steel plate. It is a construction method of a seismic isolation device that is placed between the superstructure and the substructure and supports the seismic isolation of the superstructure.
The first step of installing a reinforcing plate to which the first region of the sliding plate is joined to the main surface in the substructure, and
A resin material is poured from the peripheral edge of the main surface to the substructure around the first region and cured to form a second region of the slip plate having a friction coefficient equal to or lower than that of the first region. 2 steps and
Construction method of seismic isolation device including.

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