Reinforcement structure for seismic isolation devices

Abstract

To provide a reinforcement structure of a seismic isolator that can suppress floating of a flange plate.SOLUTION: A reinforcement structure of a seismic isolator includes: a seismic isolator 20 that is arranged between an upper structure 12 and a lower structure 14 that enable relative displacement; a mounting bolt B1 that fixes a flange plate (lower flange plate 24) of the seismic isolator 20 to the lower structure 14; and a reinforcement member 30 that is arranged astride the lower structure 14 and the flange plate, and has one end side brought into contact with the flange plate and the other end side fixed to the lower structure 14 by a bolt.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a reinforcing structure of a seismic isolation device.

Background Art

[0002] The following Patent Document 1 describes a joining structure for joining a seismic isolation device to a reinforced concrete structure. In this joining structure, a buried metal fitting is buried in a structure which is a lower structure body to which the seismic isolation device is fixed, and a fixing bolt of a lower flange plate of the seismic isolation device is screwed to this buried metal fitting.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a pulling force acts on the seismic isolation device of Patent Document 1 above, the flange plate tends to lift, and a "lever reaction force" with a point where the flange plate is pulled by the laminated rubber as a force point and the end of the flange plate as a fulcrum may act on the fixing bolt. As a result, a large pulling force acts on the fixing bolt. Further, when the flange plate is deformed, the shear deformation of the laminated rubber is inhibited, and the seismic isolation layer may not exhibit the assumed behavior, and there is a possibility that the energy absorption performance cannot be sufficiently exhibited.

[0005] In consideration of the above facts, an object of the present invention is to provide a reinforcing structure of a seismic isolation device capable of suppressing the lifting of a flange plate.

Means for Solving the Problems

[0006] The reinforcing structure for a seismic isolation device according to claim 1 comprises: a seismic isolation device disposed between a relative displaceable upper structure and a lower structure; mounting bolts for fixing the flange plate of the seismic isolation device to the lower structure; and a reinforcing member disposed across the lower structure and the flange plate, with one end in contact with the flange plate and the other end bolted to the lower structure.

[0007] In the reinforcing structure for the seismic isolation device according to claim 1, the reinforcing member is positioned across the lower structure and the flange plate of the seismic isolation device. One end of the reinforcing member is in contact with the flange plate, and the other end is bolted to the lower structure.

[0008] This prevents the flange plate from lifting when an uplift force is applied to the seismic isolation device.

[0009] Therefore, the lever reaction force acting from the flange plate on the mounting bolts that fix the flange plate to the substructure can be suppressed. As a result, the mounting bolts become less likely to break. Furthermore, the deformation of the flange plate can be suppressed. As a result, the shear deformation of the seismic isolation bearing in the seismic isolation device is less likely to be hindered, so the seismic isolation layer (the layer between the superstructure and the substructure in which the seismic isolation device is installed) behaves as intended, and the performance of the building as a seismically isolated structure is ensured for both the superstructure and the substructure.

[0010] The reinforcing structure for the seismic isolation device according to claim 2 is the reinforcing structure for the seismic isolation device according to claim 1, wherein an additional casting portion is formed on the upper surface of the lower structure, the height of which is equal to that of the flange plate, and the reinforcing member is fixed to the lower structure by anchor bolts via the additional casting portion.

[0011] In the reinforcing structure of the seismic isolation device according to claim 2, an additional casting portion is formed on the upper surface of the lower structure, and the height of the additional casting portion and the upper surface of the flange plate are made equal.

[0012] Therefore, when standard steel materials such as angle materials, channel materials, cut T-bars, and flat bars are used as reinforcing members, these steel materials can be fixed in surface contact with both the upper surface of the reinforced section and the upper surface of the flange plate. This makes it easier to maintain fixing strength. In addition, since standard steel materials can be used without bending or welding, the reinforcing members are easy to manufacture.

[0013] The reinforcing structure for a seismic isolation device according to claim 3 is the reinforcing structure for a seismic isolation device according to claim 1 or 2, wherein the reinforcing member is an angle material having a fixed portion fixed to the lower structure and a protruding portion projecting upward from the fixed portion.

[0014] In the reinforcing structure of the seismic isolation device according to claim 3, the reinforcing member is made of angle material. The protruding portion of the angle material protrudes upward from the fixing portion which is fixed to the lower structure via the additional nailing portion. As a result, the resistance to upward pulling forces is higher compared to a configuration without a protruding portion. [Effects of the Invention]

[0015] According to the present invention, the lifting of the flange plate can be suppressed. [Brief explanation of the drawing]

[0016] [Figure 1] (A) is a vertical cross-sectional view showing a reinforcing structure of a seismic isolation device according to an embodiment of the present invention, and (B) is a cross-sectional view of (A) along line BB. [Figure 2] (A) is a partially enlarged cross-sectional view showing the additional concrete section and reinforcing member of a seismic isolation device according to an embodiment of the present invention, and (B) is a view of (A) along the line BB. [Figure 3] This is a cross-sectional view showing a comparative example. [Figure 4] This is a cross-sectional view showing a modified example where the superstructure is made of steel. [Modes for carrying out the invention]

[0017] Hereinafter, a reinforcing structure for a seismic isolation device according to an embodiment of the present invention will be described with reference to the drawings. Components denoted by the same reference numerals in the respective drawings mean the same components. However, unless otherwise specified in the specification, each component is not limited to one, and a plurality of them may exist.

[0018] In addition, descriptions of overlapping configurations and reference numerals in each drawing may be omitted. Note that the present disclosure is not limited to the following embodiments, and appropriate changes can be made and implemented, such as omitting configurations, replacing them with different configurations, and combining one embodiment and various modifications within the scope of the object of the present disclosure.

[0019] In each drawing, the directions indicated by arrows X and Y are directions along the horizontal plane and are perpendicular to each other. The direction indicated by arrow Z is a direction along the vertical direction (up and down direction). In each figure, the directions indicated by arrows X, Y, and Z are assumed to coincide with each other.

[0020] <Reinforcing Structure of Seismic Isolation Device> The reinforcing structure of the seismic isolation device of the present invention is a structure for reinforcing the seismic isolation device 20 applied to the building 10 shown in Fig. 1(A). The building 10 is an existing building, and the seismic isolation device 20 in this existing building is reinforced by the reinforcing structure described below.

[0021] The building 10 is a seismic isolation building in which the upper structure 12 and the lower structure 14 are horizontally displaceable relative to each other by the seismic isolation device 20. As an example, the upper structure 12 is a building having a framework in which beams are arranged along the X direction and the Y direction.

[0022] (Building) The upper structure 12 and the lower structure 14 of the building 10 are each made of reinforced concrete or steel frame reinforced concrete. Protrusions 12A and 14A, which are pedestals to which the seismic isolation device 20 is fixed, are formed on the upper structure 12 and the lower structure 14, respectively. Both the protrusions 12A and 14A are rectangular parallelepipeds and are arranged at the same position in a top view.

[0023] The concrete protrusion 12A projects downward from the lower surface of the superstructure 12. A steel base plate 12B is fixed to the lower end surface of the protrusion 12A. When viewed from above, the base plate 12B is substantially the same shape as the protrusion 12A. The protrusion 12A and the base plate 12B are fixed together by cap nuts and bolts welded to the upper surface of the base plate 12B, or by stud bolts welded to the upper surface of the base plate 12B (not shown).

[0024] Similarly, the concrete protrusion 14A projects upward from the upper surface of the substructure 14. A steel base plate 14B is fixed to the upper end surface of the protrusion 14A. When viewed from above, the base plate 14B is substantially the same shape as the protrusion 14A. The protrusion 14A and the base plate 14B are fixed in the same manner as the protrusion 12A and the base plate 12B.

[0025] (Seismic isolation device) The seismic isolation device 20 is positioned between the superstructure 12 and the substructure 14 and comprises an upper flange plate 22, a lower flange plate 24, and laminated rubber bearings 26. The layer between the superstructure 12 and the substructure 14 in which the seismic isolation device 20 is installed constitutes the seismic isolation layer of the building 10.

[0026] The upper flange plate 22 and the lower flange plate 24 are fixed to the upper and lower surfaces of the laminated rubber bearing 26, respectively, and as shown in Figure 1(B), they are circular steel plates in plan view that protrude outwards from the laminated rubber bearing 26.

[0027] As shown in Figure 1(A), the upper flange plate 22 is fixed to the protrusion 12A, sandwiching the base plate 12B. The upper flange plate 22 and the protrusion 12A are fixed together by mounting bolts B1. A cap nut (not shown) for screwing the mounting bolts B1 into is embedded in the protrusion 12A.

[0028] Similarly, the lower flange plate 24 is fixed to the protrusion 14A, sandwiching the base plate 14B. Both the lower flange plate 24 and the protrusion 14A are fixed by mounting bolts B1. Cap nuts (not shown) for screwing the mounting bolts B1 into are also embedded in the protrusion 14A.

[0029] (Reinforcement structure) The seismic isolation device 20 is reinforced by a reinforcing member 30. In order to reinforce the seismic isolation device 20 with the reinforcing member 30, an additional casting portion 40 is formed on the upper surface of the lower structure 14, with the same height as the lower flange plate 24.

[0030] (Reinforcement structure - additional concrete casting section) As shown in Figure 2(A), the additional concrete layer 40 is formed in contact with the protrusion 14A. The additional concrete layer 40 is formed of concrete or non-shrink mortar, and its upper surface is leveled to be flat.

[0031] Furthermore, the height H of the additional concrete section 40 is equal to the combined height of the protrusion 14A, the base plate 14B, and the lower flange plate 24. As a result, the upper surface of the additional concrete section 40 and the upper surface of the lower flange plate 24 are flush.

[0032] As shown in Figure 1(B), the additional coating portion 40 is formed to cover the outer circumference of the protrusion 14A and the base plate 14B in a plan view.

[0033] Reinforcement bars can be placed inside the reinforced concrete section 40 as needed. These reinforcement bars may also be welded or joined together with the anchor bars embedded in the protrusion 14A and the substructure 14.

[0034] (Reinforcement structure - Reinforcement member) As shown in Figure 2(A), the reinforcing member 30 is a steel material positioned across the lower structure 14 and the lower flange plate 24, with the lower surface of one end (end 30A) in contact with the upper surface of the lower flange plate 24, and the other end (end 30B) fixed to the lower structure 14 by anchor bolts B2 via the reinforced section 40.

[0035] Here, "arranged across the lower structure 14 and the lower flange plate 24" indicates that it is arranged from the portion outside the protrusion 14A, which is part of the lower structure 14, to the lower flange plate 24. "Via the additional casting portion 40" indicates that the additional casting portion 40 is sandwiched between the reinforcing member 30 and the lower structure 14, which are fixed to each other.

[0036] As shown in Figure 2(B), the reinforcing member 30 is an angle material having a fixed portion 32 fixed to the lower structure and a protruding portion 34 that protrudes upward from the fixed portion 32.

[0037] As shown in Figure 1(B), multiple reinforcing members 30 are arranged around the laminated rubber bearing 26 in the seismic isolation device 20. For example, eight reinforcing members 30 are arranged such that the covering portion 30C that covers the lower flange plate 24 is positioned at approximately equal intervals in the circumferential direction of the circular laminated rubber bearing 26.

[0038] Furthermore, the separation distance W between the end portion 30A of the reinforcing member 30 on the laminated rubber bearing 26 side and the laminated rubber bearing 26 shall be set at a distance greater than or equal to a predetermined distance. The "predetermined distance" is the distance along the radial direction of the laminated rubber bearing 26, and is the distance at which the laminated rubber bearing 26 and the reinforcing member 30 do not come into contact when the laminated rubber bearing 26 undergoes limit horizontal deformation.

[0039] Furthermore, each reinforcing member 30 and the substructure 14 are fixed by multiple anchor bolts B2 (two in this embodiment).

[0040] As shown in Figure 2(A), the anchor bolt B2 penetrates the additional anchor section 40, and its lower end is fixed to the substructure 14. The anchor bolt B2 is a post-installed anchor bolt, and various types of anchoring methods, such as metal or adhesive, can be used.

[0041] Furthermore, if the joint strength between the reinforced section 40 and the lower structure 14 is sufficiently large, the lower end of the anchor bolt B2 may be fixed to the reinforced section 40.

[0042] (Other configurations) In the above description, it was explained that an additional casting portion 40 is formed on the upper surface of the lower structure 14, with the same height as the lower flange plate 24, and that the reinforcing member 30 is fixed to the lower structure 14 via the additional casting portion 40.

[0043] As shown in Figure 1(A), in this embodiment, an additional concrete section 60 is formed on the lower surface of the superstructure 12, with the same height as the upper flange plate 22, and the reinforcing member 50 is fixed to the superstructure 12 via the additional concrete section 60.

[0044] The configuration of the reinforced concrete section 60 formed on the lower surface of the superstructure 12, and the reinforcing member 50 fixed to the superstructure 12 via the reinforced concrete section 60, are the same as those of the reinforced concrete section 40 and reinforcing member 30 described above, except that their vertical arrangement is reversed, and therefore no further explanation is provided. Furthermore, the effects obtained by these reinforced concrete section 60 and reinforcing member 50 are the same as those obtained by the reinforced concrete section 40 and reinforcing member 30, which will be described later.

[0045] <Mechanism and Effects> In the reinforcement structure of the seismic isolation device according to an embodiment of the present invention, as shown in Figure 2(A), the reinforcing member 30 is positioned across the lower structure 14 and the lower flange plate 24 of the seismic isolation device 20. The lower surface of one end (end 30A) of the reinforcing member 30 is in contact with the upper surface of the lower flange plate 24, and the other end (end 30A) is bolted to the lower structure 14.

[0046] This prevents the lower flange plate 24 from lifting up (in other words, from separating the lower flange plate 24 from the base plate 14B) when an uplift force is applied to the seismic isolation device 20. Furthermore, even if the lower flange plate 24 does lift up, the height to which it lifts can be suppressed.

[0047] Therefore, the lever reaction force acting from the lower flange plate 24 to the mounting bolt B1 (see Figure 1) that fixes the lower flange plate 24 to the lower structure 14 can be suppressed. As a result, the mounting bolt B1 becomes less likely to break. In addition, the deformation of the lower flange plate 24 can be suppressed. As a result, the shear deformation of the laminated rubber bearing 26 in the seismic isolation device 20 is less likely to be hindered, so the seismic isolation layer behaves as intended, and the performance of the superstructure 12 and the lower structure 14 as a seismically isolated building is ensured.

[0048] Figure 3 shows a "comparative example." In the comparative example, the additional concrete section 40 and the reinforcing member 30 are not formed. In the comparative example, when an uplift force is applied to the seismic isolation device 200, the lower flange plate 240 tends to lift up. As a result, a "lever reaction force" may act on the mounting bolt B10, with the point P1 where the lower flange plate 240 is pulled from the laminated rubber 260 as the point of force application and the end P2 of the lower flange plate 240 as the fulcrum.

[0049] As a result, a large tensile force acts on the mounting bolt B10. Furthermore, if the lower flange plate 240 deforms, the shear deformation of the laminated rubber 260 may be inhibited, potentially preventing the seismic isolation layer from behaving as intended and failing to fully exhibit its energy absorption performance.

[0050] To resist this kind of "lever reaction force," one could consider replacing the lower flange plate 240 with a thicker one. However, since the existing seismic isolation device 200 is constantly subjected to an upper load, replacement is difficult.

[0051] It is also conceivable to increase the number of mounting bolts B10 that secure the lower flange plate 240 to the substructure. However, this would require drilling holes in both the lower flange plate 240 and the substructure, making installation difficult.

[0052] In contrast, the reinforcement structure for the seismic isolation device according to the embodiment of the present invention can resist the "lever reaction force" without replacing the seismic isolation device 20 or increasing the number of mounting bolts B1.

[0053] Furthermore, in the reinforcement structure of the seismic isolation device according to the embodiment of the present invention, as shown in Figure 2(A), an additional concrete layer 40 is formed on the upper surface of the lower structure 14, and the height of the additional concrete layer 40 and the upper surface of the lower flange plate 24 are made equal.

[0054] Therefore, when angle material, which is a standard steel material, is used as the reinforcing member 30, the fixing portion 32 of this steel material can be fixed in a state where it is in surface contact with both the upper surface of the additional mounting portion 40 and the upper surface of the lower flange plate 24. This makes it easier to maintain fixing strength. In addition, since standard steel material can be used without bending or welding, the reinforcing member 30 is easy to manufacture.

[0055] Furthermore, in the reinforcing structure of the seismic isolation device according to the embodiment of the present invention, the reinforcing member 30 is made of angle material. The protruding portion 34 of the angle material protrudes upward from the fixing portion 32 which is fixed to the lower structure 14 via the additional casting portion 40. As a result, the resistance to upward pulling forces is higher compared to a configuration without the protruding portion 34.

[0056] <Variation> In the above embodiment, as shown in Figure 1, an additional casting portion 60 is formed on the lower surface of the superstructure 12, with the same height as the upper flange plate 22, and the reinforcing member 50 is fixed to the superstructure 12 via the additional casting portion 60. However, the embodiments of the present invention are not limited to this.

[0057] For example, if the superstructure 16 is made of steel, as shown in Figure 4, the additional concrete section 60 and reinforcing member 50 shown in Figure 1 do not need to be used. In such cases, mounting bolts B3 are used instead of mounting bolts B1 that fix the upper flange plate 22 to the superstructure 12.

[0058] Mounting bolt B3 is a bolt that fixes the upper flange plate 22 to the base plate 16A of the superstructure 16. Mounting bolt B3 fixes the upper flange plate 22 and the base plate 16A by sandwiching them between the bolt head and the nut.

[0059] In this case, by increasing the number of mounting bolts B3 to more than the number of mounting bolts B1, it is possible to suppress the lifting of the upper flange plate 22 (i.e., the upper flange plate 22 separating from the base plate 16A) when an uplift force is applied to the seismic isolation device 20.

[0060] Furthermore, in the above embodiment, eight reinforcing members 30 were arranged such that the positions of the covering portion 30C that covers the lower flange plate 24 were approximately equally spaced in the circumferential direction of the circular laminated rubber bearing 26. However, the embodiments of the present invention are not limited to this. In other words, the number and position of the reinforcing members 30 are not particularly limited.

[0061] As an example, the reinforcing members 30 may be arranged in multiples other than eight so as to be approximately equal in distance around the laminated rubber bearing 26. By arranging the reinforcing members 30 at approximately equal distances around the laminated rubber bearing 26, it is easier to suppress the lifting of the lower flange plate 24 regardless of the direction in which the uplift force acting on the seismic isolation device 20 is eccentric.

[0062] As another example, the reinforcing members 30 may be arranged in large numbers on the X-direction end and Y-direction end of the lower flange plate 24. Arranging the reinforcing members 30 in this way makes it easier to suppress the lifting of the lower flange plate 24 when an uplift force acts on the seismic isolation device 20 along the axial direction of the superstructure 12.

[0063] As another example, the reinforcing members 30 may be arranged in greater numbers on the end side of the lower flange plate 24 in the weak axis direction of the upper structure 12, in addition to the X and Y directions. By arranging the reinforcing members 30 in this manner, it is easier to suppress the lifting of the lower flange plate 24 when an uplift force acts on the seismic isolation device 20 along the weak axis direction of the upper structure 12.

[0064] Furthermore, although angle material is used as a reinforcing member in the above embodiment, the embodiments of the present invention are not limited to this. Instead of angle material, standard steel materials such as channel material, cut T, or flat bar may be used. When using steel materials without protrusions, such as flat bar, it is preferable to increase the thickness of the steel material or increase the quantity of steel material compared to when using steel materials with protrusions.

[0065] Furthermore, although the above embodiment provides an additional casting section 40, the embodiments of the present invention are not limited to this. For example, if a protrusion with a large overhang width relative to the lower flange plate 24 is formed on the lower structure 14, as shown by the dashed line in Figure 2(A), a spacer or the like (not shown) may be placed on the upper surface of this protrusion 14C. The spacer may be made of steel, non-shrink mortar, or the like.

[0066] In this case, the height of the upper surface of this spacer should be equal to the height of the upper surface of the lower flange plate 24. Furthermore, it is preferable to level the upper surface of the protrusion 14C to a flat surface. However, if non-shrink mortar is used as the spacer, the upper surface of the spacer should be leveled to a flat surface. Also, spacers only need to be provided at the positions where the reinforcing member 30 is placed. The additional concrete pouring portion 60 can also be omitted in a similar manner.

[0067] Furthermore, in cases where a protrusion 14C with a large overhang width is formed relative to the lower flange plate 24 and no additional reinforcement portion 40 is provided, the "reinforcement member arranged across the lower structure and the flange plate" in this application refers to a reinforcement member 30 that is arranged from the portion of the protrusion 14C, which is part of the lower structure 14, that is outside the lower flange plate 24, to the lower flange plate 24.

[0068] In other words, the "reinforcement member positioned across the lower structure and the flange plate" in this application refers to a reinforcement member positioned from the portion outside the lower flange plate 24 to the lower flange plate 24.

[0069] Furthermore, in the above embodiment, the protrusions 12A and 14A, which are the bases to which the seismic isolation device 20 is fixed, are in the shape of a rectangular parallelepiped, but the embodiments of the present invention are not limited to this. At least one of the protrusions 12A and 14A may be a polygonal prism or cylinder other than a quadrilateral.

[0070] For example, if the protrusion 14A is a rectangular prism, the reinforcing members 30 may be placed in the center of each side of the polygon, and the extension direction of the reinforcing members 30 may be aligned with the perpendicular to each side. Alternatively, if the protrusion 14A is a cylinder, the reinforcing members 30 may be placed at arbitrary intervals along the circumference of the circle, and the extension direction of the reinforcing members 30 may be aligned with the radial direction of the circle. [Explanation of Symbols]

[0071] 12 Superstructure 14 Substructure 14A Protrusion (lower structure) 20 Seismic isolation devices 24 Lower flange plate (flange plate) 30 Reinforcement members 32 Fixed part 34 Protrusion 40 Additional coating section 50 Reinforcement members 60 Additional coating section

Claims

1. A seismic isolation device is positioned between a superstructure and a substructure that are capable of relative displacement, Mounting bolts for fixing the flange plate of the seismic isolation device to the lower structure, A reinforcing member is positioned across the lower structure and the flange plate, with one end in contact with the flange plate and the other end bolted to the lower structure. A reinforcing structure for seismic isolation devices, equipped with the above features.

2. An additional casting portion is formed on the upper surface of the lower structure, where the height of the upper surface is equal to that of the flange plate. The reinforcing member is fixed to the lower structure by anchor bolts via the additional nailing portion. A reinforcing structure for a seismic isolation device according to claim 1.

3. The reinforcing member is an angle material having a fixed portion fixed to the lower structure and a protruding portion projecting upward from the fixed portion. A reinforcing structure for a seismic isolation device according to claim 1 or 2.

Images