KR20210039851A - Sliding pendulum bearing for earthquake proof - Google Patents

Abstract

The present invention relates to a sliding pendulum support which comprises: first and second sliding plates each having a curved surface shape concave in one direction, wherein the curved surfaces are installed to face each other; first and second steel plates installed on the concave curved surfaces of the first and second sliding plates, respectively; first and second sliding blocks provided between the first and second steel plates and having opposite surfaces formed in a convex or concave shape so that the opposite surfaces are disposed to engage with each other; a first ring member provided between the first sliding block and the first steel plate; and a second ring member provided between the second sliding block and the second steel plate. The first ring member and the second ring member can slide on the first steel plate and the second steel plate, respectively, and enable the first and second sliding blocks to return to an equilibrium position when external force is released. The first ring member and the second ring member each have a hollow at the center, and a solid lubricant. According to the present invention, the sliding pendulum support can sufficiently maintain earthquake energy dissipation performance by securing a ground contact area and dissipating stress while having design flexibility.

Description

Sliding pendulum bearing for seismic resistance {SLIDING PENDULUM BEARING FOR EARTHQUAKE PROOF}

The present invention relates to a sliding pendulum support as a seismic isolator or a seismic isolator for protecting a structure from an earthquake.

The seismic isolator that isolates the structure from earthquakes and minimizes the transmission of seismic energy to reduce damage can be largely divided into two types: a friction pendulum system type and a lead-rubber bearing type. The invention relates to a double friction pendulum bearing.

The friction pendulum bearing is a principle that dissipates seismic force by reciprocating the friction material on a spherical concave surface having a certain curved surface when an earthquake occurs.It dissipates energy by the frictional force of the friction material and returns to its original position due to the curved surface of the sliding surface. It is a seismic isolator with a characteristic to be restored

However, since such conventional friction pendulum bearings are difficult to change the coefficient of friction due to structural characteristics, it is difficult to design an appropriate coefficient of friction, and due to the difficulty of machining precision of a curved surface, it is limited to improve the adhesion of the friction material, thereby reducing the load. It does not disperse uniformly, and also causes a lot of displacement according to the curvature, and frictional heat is generated while the friction material is moving, resulting in poor energy dissipation capability.

The matters described in the background art are provided to aid in understanding the background of the invention, and may include matters other than the prior art already known to those of ordinary skill in the field to which this technology belongs.

Korean Patent Application Publication No. 10-2005-0105423

The present invention was conceived to solve the above-described problems, and the present invention is to provide a sliding pendulum support for seismic resistance capable of sufficiently maintaining seismic energy dissipation performance through securing a ground area and dissipating stress while having design flexibility. There is this.

The sliding pendulum support for seismic resistance according to an aspect of the present invention includes first and second sliding plates that each have a concave curved shape in one direction and are installed so that the curved surfaces face each other, and the concave curved surfaces of the first and second sliding plates First and second steel plates respectively installed on the first and second steel plates, provided between the first and second steel plates, and the facing surfaces are formed in a convex or concave shape so that the facing surfaces are arranged to engage with each other. , A first ring member provided between the first sliding block and the first steel plate, and a second ring member provided between the second sliding block and the second steel plate, and the first ring member and the first 2 The ring member is slidable on the first steel plate and the second steel plate, respectively, so that the first and second sliding blocks return to the equilibrium position when the external force is released, and has a hollow in the center, and contains a solid lubricant. It characterized in that it includes.

In addition, the first sliding block has a convex curved shape toward the second sliding block, and the second sliding block has a concave curved surface facing the first sliding block.

Here, the first and second ring members include any one of Filled PTFE (Polytetrafluoroethylene), Woven PTFE, UHMWPE (Ultra-high-molecular Weight polyethylene), and Polyamide resin, or a combination thereof. It is characterized.

Further, the first ring member and the second ring member are partially inserted into the first and second mounting grooves formed in the first sliding block and the second sliding block, respectively.

Meanwhile, the first and second ring members may further include third and fourth ring members provided on each of the first and second sliding blocks so as to form a concentric circle on each of the first and second ring members.

In addition, the third and fourth ring members are respectively disposed inside the hollows of the first and second ring members.

In addition, the third ring member and the fourth ring member are partially inserted into the third and fourth mounting grooves formed in the first sliding block and the second sliding block, respectively.

Meanwhile, a plurality of dimples are formed on the curved surfaces of the first and second steel plates.

Here, the plurality of dimples are formed to have a larger gap between the dimples as they are closer to the center of the curved surface.

According to the sliding pendulum support for earthquake resistance of the present invention, due to the partial curvature due to the hollow formed on the sliding surface of the sliding block, it is possible to minimize the manufacturing tolerance according to the radius of curvature, and contribute to the improvement of the adhesion between the sliding plate and the sliding block. By doing so, it is not only advantageous in the distribution of the load, but also the design of an appropriate coefficient of friction is facilitated by controlling the area of the contact surface according to the size of the hollow formed on the sliding surface of the sliding block. The combination of friction and low-friction composites enables the realization of various coefficients of friction by combining the coefficients of friction, and the part with large seismic displacement due to the reduction of the coefficient of friction by the dimple against the steel plate corresponding to the sliding surface of the sliding plate. Due to the high coefficient of friction, it prevents the earthquake displacement from becoming excessively large during an earthquake, and contributes to the improvement of restoration performance, and by adjusting the shape or arrangement of the dimples, the design of an appropriate coefficient of friction through the control of the coefficient of friction Can be facilitated.

1 is a side cross-sectional view showing a sliding pendulum support according to a first embodiment of the present invention.
2 is a plan view showing a friction surface in the sliding pendulum support according to the first embodiment of the present invention.
3 is a side cross-sectional view showing a state during rotation in the sliding pendulum support according to the first embodiment of the present invention.
4 is a side cross-sectional view showing a state at a maximum allowable displacement in the sliding pendulum support according to the first embodiment of the present invention.
5 is a plan view showing a sliding block in a sliding pendulum support according to a second embodiment of the present invention.
6 is a side cross-sectional view showing a slang reading pendulum support according to a third embodiment of the present invention.
7 is a plan view showing a steel plate in a sliding pendulum support according to a third embodiment of the present invention.
8 is a plan view showing a steel plate in a sliding pendulum support according to a fourth embodiment of the present invention.
9 is an image showing the stress distribution for the sliding pendulum support according to the first embodiment of the present invention.
10 is an image showing the stress distribution for each configuration of the sliding pendulum support according to the first embodiment of the present invention.

In the present invention, various modifications may be made and various embodiments may be provided, and specific embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to a specific embodiment, and should be understood as including all changes, equivalents, or substitutes included in the technical spirit and scope of the present invention, and may be modified in various other forms. It can be, and the scope of the present invention is not limited to the following examples.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, and the same reference numerals are assigned to the same or corresponding components regardless of the reference numerals, and redundant descriptions thereof will be omitted.

1 is a side cross-sectional view showing a sliding pendulum support according to a first embodiment of the present invention, and FIG. 2 is a plan view showing a friction surface in a sliding pendulum support according to a first embodiment of the present invention. On the other hand, as shown in FIG. 2, when the upper and lower portions form the same structure symmetrically with each other, reference numerals of the configurations corresponding to each other by symmetry will be described together, and the same will be applied in the following drawings.

1 and 2, the sliding pendulum support 100 according to the first embodiment of the present invention is installed on an installation surface 1 (shown in FIGS. 3 and 4) to provide a building, a bridge, or various objects in a building. It is installed to support the load of various structures (2; shown in Figs. 3 and 4) including, etc., and to protect the structure 2 from ground motion during an earthquake, the first and second sliding plates 110 and 120, the first and second sliding plates 110 and 120, respectively. It may include first and second steel plates 130 and 140, first and second sliding blocks 150 and 160, and first and second ring members 170 and 180.

The first and second sliding plates 110 and 120 are installed to face each other. For example, the first sliding plate 110 located on the upper side of the first and second sliding plates 110 has a fixing part 111 provided at the corner side of the structure 2 using bolts or the like. 3 and 4) The second sliding plate 120, which can be fixed to the bottom surface and located at the lower side, has a fixing part 121 provided at each of the corners thereof with a bolt or the like on the installation surface 1; FIG. 3 And it may be fixed to the upper surface) shown in Figure 4). In addition, the first and second sliding plates 110 and 120 may be made of steel together with the first and second sliding blocks 150 and 160, and of course, the material may be variously selected according to the load of the structure.

The first and second steel plates 130 and 140 may be made of stainless steel, and are installed to be fixed by various methods, including bonding or bolting, respectively, on opposite surfaces of the first and second sliding plates 110 and 120. , To have first and second curved surfaces 131 and 141 concave in one direction, respectively. The first and second steel plates 130 and 140 are disposed so that the first and second curved surfaces 131 and 141 face each other to form a space having a curvature inside. These first and second curved surfaces 131 and 141 Can be polished to be smooth.

The first and second sliding blocks 150 and 160 are installed between the first and second steel plates 130 and 140, respectively, and have a concave third curved surface 151 and a convex fourth curved surface 161 so as to have a slidable interview with each other. Each of these is formed. In the example, the third curved surface 151 of the first sliding block 150 disposed on the upper side is concave in one direction (downward direction), and the fourth curved surface 161 of the second sliding block 160 disposed at the lower side. ) May be formed to be convex in one direction (upward direction), and vice versa.

Accordingly, the first and second sliding blocks 150 and 160 cause sliding due to an external force to each other, but when the external force is released, the first and second sliding blocks 150 and 160 may return to their original equilibrium position.

Next, the first and second ring members 170 and 180 interview each of the first and second curved surfaces 131 and 141 and convex fifth and sixth corresponding to the first and second curved surfaces 131 and 141 respectively so as to be slidable. By having the curved surfaces 171 and 181, provided on one side of each of the first and second sliding blocks 150 and 160, the first and second sliding blocks 150 and 160 return to their original equilibrium position when the external force is released, It is made of a composite material such as a solid lubricant having a hollow (172, 182) in the center. Here, the hollow (172,182) minimizes the non-contact phenomenon with the central portion of the curvature of the first and second curved surfaces (131, 141) to ensure a uniform friction area, and the pressure stress (vertical stress) varies according to the size. , The coefficient of friction can be changed. That is, the larger the hollows 172 and 182, the smaller the frictional area, thereby increasing the acupressure stress and reducing the coefficient of friction.

The first and second ring members 170 and 180 may be included so as to be located at a portion where various solid lubricants are rubbed, each of which is a solid lubricant, such as Filled PTFE (Polytetrafluoroethylene), Woven PTFE, UHMWPE (Ultra-high-molecular Weight Polyethylene). ) And polyamide resin, or a combination thereof. That is, the first and second ring members 170 and 180 are the same as each other and include any one of Filled PTFE (Polytetrafluoroethylene), Woven PTFE, UHMWPE (Ultra-high-molecular Weight Polyethylene), and polyamide resin, or Each contains one of Filled PTFE (Polytetrafluoroethylene), Woven PTFE, UHMWPE (Ultra-high-molecular Weight Polyethylene), and Polyamide resin to be different from each other, so that a combination of different solid lubricants can be made. Here, PTFE (Polytetrafluoroethylene) is known as Teflon as a trade name, and physical properties can be adjusted by mixing a mixture of carbon or molybdenum. In the present invention, it is said that the first and second ring members 170 and 180 contain this, for example, pure water. PTFE (Virgin PTFE), carbon or molybdenum mixed PTFE (Filled PTFE), PTFE (Woven PTFE) reinforced by impregnating a PTFE mixture with glass fiber, etc. can be applied. UHMWPE (Ultra-high-molecular Weight polyethylene) is a thermoplastic polyethylene with a very large molecular mass, and is resistant to abrasion and impact, and can be used as a single resin when applied to a support. Polyamide resin is called a nylon resin, has good abrasion resistance, and can be applied in the form of a thermoplastic resin having a small coefficient of friction.

The first and second ring members 170 and 180 may have a configuration in which the above-described solid lubricant or other solid lubricant is formed as a single unit, or may be included as a part by being attached to a separate member such as a steel plate. The first and second ring members 170 and 180 may have a structure in which the above-described solid lubricant or various other solid lubricants are made of a fabric, and thus resin is impregnated and cured.

The first and second ring members 170 and 180 are attached to each of the outer surfaces of the first and second sliding blocks 150 and 160 with a fixing member such as adhesive or bolting, or the first and second sliding blocks 150 and 160 as in this embodiment. ) Is mounted so as to protrude from the first mounting groove 152 and the second mounting groove 162 respectively formed on one side of the side, and can be attached with a fixing member such as adhesive or bolting.

Referring to FIG. 3, when an earthquake occurs, the first and second sliding between the first and second steel plates 130 and 140 fixed to the facing surfaces of the first and second sliding plates 110 and 120, respectively, according to a component of an external force. Blocks 150 and 160 may rotate through the first and second ring members 170 and 180, and at this time, relative rotation is possible between the first and second sliding blocks 150 and 160, for example, the structure 2 It is possible to incline at a certain angle α with respect to the horizontal plane, and at this time, it is possible to dissipate the seismic energy applied to the structure 2.

In addition, referring to FIG. 4, when an earthquake occurs, the first and second sliding blocks 150 and 160 between the first and second steel plates 130 and 140 connect the first and second ring members 170 and 180 according to the component of the external force. Sliding through the medium allows the structure 2 to move horizontally by a predetermined distance d from its original position, and at this time, it is possible to dissipate the seismic energy applied to the structure 2.

Next, FIG. 5 is a plan view showing a sliding block in a sliding pendulum support according to a second embodiment of the present invention.

5, the sliding pendulum support 200 according to the second embodiment of the present invention is different from the sliding pendulum support 100 according to the first embodiment of the present invention. A third ring member 291 provided on one side of the first sliding block 250 to be located inside the hollow 272, and a second sliding block to be located inside the hollow 282 of the second ring member 280 Except that the fourth ring member 292 provided on one side of 260 is additionally provided, it is the same as the sliding pendulum support 100 having the ring-shaped composite material according to the first embodiment of the present invention. In this case, redundant descriptions will be omitted.

The third and fourth ring members 291 and 292 are formed in a ring shape, so that the hollows 293 and 294 are formed in the center, and the first and second curved surfaces 131 and 141; Having convex seventh and eighth curved surfaces 295 and 296 corresponding to the second curved surfaces 131 and 141, respectively, the first and second curved surfaces are positioned inside the hollows 272 and 282 of the first and second ring members 270 and 280, respectively. It is provided in each of the first and second sliding blocks 250 and 260 to form a concentric circle in each of the ring members 270 and 280, and may be formed of at least one. Of course, it can be arranged to form a concentric circle.

The third and fourth ring members 291 and 292 may be included so as to be located at a portion where various solid lubricants are rubbed, each of which is a solid lubricant, such as Filled PTFE (Polytetrafluoroethylene), Woven PTFE, UHMWPE (Ultra-high-molecular Weight Polyethylene). ) And polyamide resin, or a combination thereof. That is, the third and fourth ring members 291 and 292 are the same as each other and include any one of Filled PTFE (Polytetrafluoroethylene), Woven PTFE, UHMWPE (Ultra-high-molecular Weight Polyethylene), and polyamide resin, or Each contains one of Filled PTFE (Polytetrafluoroethylene), Woven PTFE, UHMWPE (Ultra-high-molecular Weight Polyethylene), and Polyamide resin to be different from each other, so that a combination of different solid lubricants can be made. Here, PTFE (Polytetrafluoroethylene) is known as Teflon as a trade name, and physical properties can be adjusted by mixing a mixture of carbon and molybdenum, but the third and fourth ring members 291 and 292 in the present invention are said to contain this, for example, pure water. PTFE (Virgin PTFE), carbon or molybdenum mixed PTFE (Filled PTFE), PTFE (Woven PTFE) reinforced by impregnating a PTFE mixture with glass fiber, etc. can be applied. UHMWPE (Ultra-high-molecular Weight polyethylene) is a thermoplastic polyethylene with a very large molecular mass, and is resistant to abrasion and impact, and can be used in the form of a single resin when applied to a support. Polyamide resin is called a nylon resin, has good abrasion resistance, and can be applied in the form of a thermoplastic resin having a small coefficient of friction.

The third and fourth ring members 291 and 292 may have a configuration in which the solid lubricant or other solid lubricant described above is formed as a single unit, or may be included as a part by being attached to a separate member such as a steel plate. The third and fourth ring members 291 and 292 may have a configuration in which the above-described solid lubricant or various other solid lubricants are made of fabric and impregnated and cured with resin, and the same material as the first and second ring members 270 and 280 By being made of or made of different materials, it is possible to implement various coefficients of friction by mixing various composite materials.

The third and fourth ring members 291 and 292 are attached to each of the outer surfaces of the first and second sliding blocks 250 and 260 with a fixing member such as an adhesive or bolting, or as in the present embodiment, the first and second sliding blocks 250 and 260 ) Is mounted so as to protrude from the third mounting groove 252 and the fourth mounting groove 262 respectively formed on one side of the), and can be attached with a fixing member such as adhesive or bolting.

Next, FIG. 6 is a side cross-sectional view showing a sliding pendulum support according to a third embodiment of the present invention, and FIG. 7 is a plan view showing a steel plate in the sliding pendulum support according to a third embodiment of the present invention.

6 and 7, the sliding pendulum support 300 according to the third embodiment of the present invention is similar to the sliding pendulum support 100 according to the first embodiment of the present invention. And first and second steels respectively installed on opposite surfaces of the second sliding plates 310 and 320 and the first and second sliding plates 310 and 320 and having concave first and second curved surfaces 331 and 341, respectively. Plates 330 and 340 and the first and second steel plates 330 and 340 are installed between the first and second steel plates 330 and 340, respectively, and each having a concave third curved surface 351 and a convex fourth curved surface 361 so as to slidably interview each other. Convex fifth and sixth curved surfaces corresponding to each of the first and second curved surfaces 331 and 341 so as to be slidable by interviewing each of the first and second sliding blocks 350 and 360 and the first and second curved surfaces 331 and 341 With (371,381), it is provided in each of the first and second sliding blocks (350,360), so that the first and second sliding blocks (350,360) return to the equilibrium position when the external force is released, and has a hollow (372,382) in the center The first and second ring members 370 and 380 including a solid lubricant may be included, and the first and second ring members 370 and 380 are the first mounting grooves 352 of the first and second sliding blocks 350 and 360 And the second mounting grooves 362, respectively, but may be attached to the outer surfaces of the first and second sliding blocks 350 and 360 as they are without a groove structure.

In the sliding pendulum support 300 according to the third embodiment of the present invention, the description of the same parts as the sliding pendulum support 100 having a ring-shaped composite material according to the first embodiment will be omitted, and the differences will be mainly described. do.

In this embodiment, the first and second steel plates 330 and 340 may have a plurality of dimples 332 and 342 formed at the centers of the first and second curved surfaces 331 and 341. In the first and second curved surfaces 331 and 341, the dimples 332 and 342 are formed in the shape of grooves to reduce the friction coefficient, and the friction coefficient can be adjusted according to the shape, arrangement structure, number, distribution, etc. That is, as the number of dimples 332 and 342 increases, the friction area is reduced, and thus, the pressure stress increases, so that the coefficient of friction decreases. Accordingly, the regions in which the dimples 332 and 342 are formed on the first and second curved surfaces 331 and 341 correspond to the relatively low coefficient of friction region, and the region where the dimples 332 and 342 are not formed corresponds to the relatively high coefficient of friction region.

The diameter of the area in which the dimples 332 and 342 are formed in the first and second steel plates 330 and 340 may be 50 to 100% of the diameter of the first and second sliding blocks 350 and 360. Accordingly, reliability and efficiency of restoration of the first and second sliding blocks 350 and 360 may be improved.

Next, FIG. 8 is a plan view showing a steel plate in a sliding pendulum support according to a fourth embodiment of the present invention.

Referring to FIG. 8, the sliding pendulum support 400 according to the fourth embodiment of the present invention is different from the sliding pendulum support 300 according to the third embodiment of the present invention. 430, 440) In the region where the dimples 432 and 442 are arranged in each of the first and second curved surfaces 431 and 441, the distance between the dimples 432 and 442 is made larger than the edge of the center in the region where the dimples 432 and 442 are arranged. In accordance with the third embodiment of the present invention, except that the center portion is compared with the edge, the number of dimples (432, 442) is reduced to increase the friction area, and thereby the friction coefficient is increased due to a decrease in acupressure stress. Since it is the same as the sliding pendulum support 300, a redundant description will be omitted. That is, the closer to the center of the curvature surface, the wider the gap between the dimples is formed.

9 is an image showing the stress distribution for the sliding pendulum support according to the first embodiment of the present invention, and FIG. 10 is an image showing the stress distribution for each configuration of the sliding pendulum support according to the first embodiment of the present invention. to be.

As shown in FIGS. 9 and 10, when the present invention is implemented with a capacity of 3750 kN, it can be seen that the present invention has an even stress distribution not only for the overall stress distribution but also for each important configuration.

As described above, in the present invention, unlike a conventional friction pendulum bearing, by applying a hollow (Cavity) composite material to a sliding friction material applied to a ring member, the following effects can be exhibited.

① Equal ground area: Secure ground area even for uneven curvature due to manufacturing errors

② Prevention of stress concentration: Dispersion of stress concentration occurring on the edge of the composite material

③ Maintaining seismic energy dissipation performance: Minimizing the change in friction coefficient by dissipating friction heat by the hollow

④ Design flexibility: Acupressure level control through hollow design

And, by configuring the sliding blocks in the upper and lower portions, the following effects can also be exhibited.

① Economical: It can be designed in a compact size by accommodating about twice the displacement of a single friction pendulum support of the same area.

② Durability: Reduces frictional heat by reducing the sliding speed (about 1/2) to prevent damage to the sliding material during long-term use.

③ Characteristic control function: When the sliding material and the curvature are applied double, the properties can be adjusted

Although the present invention has been described with reference to the accompanying drawings, various modifications and variations can be made without departing from the technical spirit of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims and equivalents as well as the claims to be described later.

100,200,300,400: Sliding pendulum support
110,310: first sliding plate
111: fixed part
120,320: second sliding plate
121: fixed part
130,330,430: 1st steel plate
131,331,431: first curved surface
140,340,440: 2nd steel plate
141,341,441: second curved surface
150,250,350,450: first sliding block
151,351: third curved surface
152,352: first mounting groove 252: third mounting groove
160,260,360,460: second sliding block
161,361: fourth curved surface
162,362: second mounting groove 262: fourth mounting groove
170,270,370: first ring member
171,271,371: 5th curved surface
172,272,372: Hollow
180,280,380: second ring member
181,281,381: 6th curved surface
182,282,382: Hollow
291: third ring member
293: hollow 295: 7th curved surface
292: fourth ring member
294: hollow 296: eighth curved surface
332,342,432,442: Dimple

Claims (9)

First and second sliding plates each having a concave curved shape in one direction and installed so that the curved surfaces face each other;
First and second steel plates respectively installed on the concave curved surfaces of the first and second sliding plates;
First and second sliding blocks provided between the first and second steel plates and having opposite surfaces formed in a convex or concave shape so that opposite surfaces are disposed to mesh with each other;
A first ring member provided between the first sliding block and the first steel plate; And
Including a second ring member provided between the second sliding block and the second steel plate,
The first ring member and the second ring member are slidable on the first steel plate and the second steel plate, respectively, so that the first and second sliding blocks return to the equilibrium position when the external force is released, and the center It has a hollow in, characterized in that it comprises a solid lubricant,
Sliding pendulum base. The method according to claim 1,
The first sliding block has a convex curved shape toward the second sliding block, and the second sliding block has a concave curved shape with a surface facing the first sliding block,
Sliding pendulum base. The method according to claim 2,
The first and second ring members,
Filled PTFE (Polytetrafluoroethylene), Woven PTFE, UHMWPE (Ultra-high-molecular weight polyethylene), and polyamide resin (Polyamide resin), characterized in that it comprises any one or a combination thereof,
Sliding pendulum base. The method according to claim 2,
The first ring member and the second ring member are partially inserted into a first mounting groove and a second mounting groove formed in the first sliding block and the second sliding block, respectively,
Sliding pendulum base. The method according to claim 2,
Further comprising third and fourth ring members provided in each of the first and second sliding blocks so as to form a concentric circle in each of the first and second ring members,
Sliding pendulum base. The method of claim 5,
Wherein the third and fourth ring members are disposed inside the hollow of the first and second ring members, respectively,
Sliding pendulum base. The method of claim 6,
The third ring member and the fourth ring member are partially inserted into the third mounting groove and the fourth mounting groove formed in the first sliding block and the second sliding block, respectively,
Sliding pendulum base. The method according to claim 1,
Characterized in that a plurality of dimples are formed on the curved surfaces of the first and second steel plates,
Sliding pendulum base. The method of claim 8,
The plurality of dimples are formed to have a larger gap between the dimples as they are closer to the center of the curved surface,
Sliding pendulum base.

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