JP5449048B2 - Seismic isolation bearing - Google Patents

Description

  The present invention relates to a seismic isolation support for supporting seismic isolation of structures such as detached houses, buildings, and storage tanks.

  The seismic isolation bearing supporting a structure such as a building often exerts the functions of mitigation and absorption of vibrations and shocks due to the earthquake mainly for the compressive load, but sometimes the tensile load acts. For example, when a structure rolls due to an earthquake, a compressive load is applied to the seismic isolation bearing on the falling side, while a tensile load is applied to the seismic isolation support on the opposite side. Therefore, the seismic isolation bearing is required to be made in consideration of not only the compressive load but also the tensile load.

  As a conventional seismic isolation bearing, there is a structure in which a lower flange plate is enlarged in diameter and bolted on the outer periphery as disclosed in Patent Document 1. That is, when a large upward tensile load is applied, as shown in FIG. 4 of the cited document 1, means for absorbing and alleviating stress by plastically deforming the lower flange plate (mounting plate 8). It is. Similar ones are disclosed in Patent Document 2 (see particularly FIG. 3). This is because another large-diameter flange plate (mounting plate 12) is provided between the large-diameter lower flange plate (mounting plate 8) and the foundation, and plastic deformation of both flange plates (mounting plates 8, 12) This is a seismic isolation bearing with a structure that can cope with a large tensile load.

  However, like those in Patent Documents 1 and 2, the countermeasure means for deforming the lower flange plate or the like is a strong possibility that permanent deformation or residual stress may remain after an earthquake, so that it is necessary to replace it and maintenance-free. There are disadvantages that are not. In addition, increasing the diameter of the lower flange plate not only increases the cost as a seismic isolation bearing, but also has the disadvantage of increasing the construction cost due to the need to increase the size of the footing and other foundations. It is hard to say that it is a good idea.

  Moreover, like the seismic isolation bearing disclosed in Patent Document 3, the lower flange plate (lower flange 21) is bolted via a cylindrical rubber elastic body (31) whose upper surface is pressed by a circular steel plate (34). The structure of stopping is known. With such a structure, when a tensile load is applied, the elastic deformation of the rubber elastic body (31) is quickly performed until the start of bearing the tensile load at the seismic isolation portion (laminated rubber 20). The initial stress load function of relaxation and absorption is exhibited, and there is an advantage that the lower flange plate (lower flange 21) does not need to be deformed first.

  However, in the structure shown in Patent Document 3, the outer peripheral surface of the rubber elastic body (31) is exposed and is liable to cause early deterioration. Therefore, it is necessary to periodically replace the parts, which is also maintenance-free. hard. In addition, a space for projecting and deploying the rubber elastic body (31), the circular steel plate (34) and the like must be secured on the upper side of the outer peripheral portion of the lower flange plate, and there is a disadvantage that regulations on design and construction increase. is there.

JP 2005-171609 A Japanese Patent Laid-Open No. 2005-163281 JP 2008-215442 A

  In view of the above circumstances, the object of the present invention is to provide a seismic isolation bearing that can handle a tensile load as an improvement that is maintenance-free and does not increase the restrictions on design and construction. It is in.

In the invention according to claim 1, the seismic isolation portion 6 is integrally provided between the upper and lower flange plates 3 fixed to the structure foundation 1 by bolts 2 and the upper flange plate 5 attached to the structure 4. In the seismic isolation bearing
The bolt 2 through-hole 9 of the lower flange plate 3 is formed as a stepped hole having a small-diameter hole lower portion 9a and a larger-diameter receiving hole upper portion 9b, and is fitted into the small-diameter hole lower portion 9a. A restraint member 11 that has a flange 11b disposed on the upper side of the boss portion 11a in a state of being fitted into the boss portion 11a and the accommodation hole upper portion 9b, and can be fitted onto the bolt 2; and the boss portion 11a. And an annular elastic member 10 that can be fitted inside the accommodation hole upper portion 9b, and a restraining member 11 into which the boss portion 11a is fitted is inserted into the small diameter hole lower portion 9a. In the assembled state in which the bolt 2 fixes the base 1, the flange portion 11 b in which at least the lower end portion is fitted into the accommodation hole upper portion 9 b is connected to the small diameter of the lower flange plate 3 via the annular elastic member 10. The outer peripheral part 1 of the hole lower part 9a It is configured so as to press downwardly and is characterized in.

  The invention according to claim 2 is the seismic isolation bearing device according to claim 1, wherein the annular elastic member 10 is made of rubber.

  The invention according to claim 3 is the seismic isolation support device according to claim 1 or 2, wherein the upper surface 11d of the flange portion 11b and the upper surface 3a of the lower flange plate 3 are flush with each other in the assembled state. It is set to be almost flush. It is characterized by this.

  The invention according to claim 4 is the seismic isolation bearing device according to any one of claims 1 to 3, wherein the restraining member 11 is a single unit having the boss portion 11a and the saliva portion 11b integrally. It is characterized by comprising a flanged boss.

  According to the first aspect of the present invention, as will be described in detail in the section of the embodiment, when an upper or lower tensile load is applied due to an earthquake or the like, the flange portion of the restraining member fixed to the foundation and the outer peripheral portion of the lower portion of the small-diameter hole As the annular elastic member is compressed and deformed, the lower flange plate is lifted, and when the tensile load is lost, the annular elastic member is restored and returns to its original state. Therefore, the lower flange plate is not plastically deformed and parts must be replaced, and the annular elastic member can be accommodated in the lower flange plate so as not to be seen from the outside to prevent early deterioration. In addition, most of the configuration of the annular elastic member, etc. can be arranged within the thickness range of the lower flange plate, the dedicated space for mounting can be clearly reduced, and the mounting of the lower flange plate to the foundation The part can be made compact. As a result, it is possible to provide a seismic isolation bearing that can cope with a tensile load as an improved one that is maintenance-free and does not increase restrictions on design and construction.

  According to the second aspect of the present invention, the annular elastic member is formed of a rubber that is easily marketable and easily available, and has the added advantage of being highly productive and inexpensive.

  According to the invention of claim 3, the attachment portion to the foundation of the lower flange plate can be configured within the thickness range of the lower flange plate except for the bolt head portion, and a dedicated space portion for attachment is provided. There is an advantage that a more compact configuration can be obtained without the need to ensure.

  According to the invention of claim 4, the restraining member is composed of a single flanged boss integrally having the boss part and the saliva part, compared to a case where the boss part and the saliva part are separated. This is advantageous in terms of strength, and has the advantage that the number of parts is reduced and the assemblability and disassembly are improved.

Front view of partially cutout showing the structure of seismic isolation bearing Expanded sectional view of the main part showing the mounting structure of the lower flange plate to the foundation (Example 1) 2 is a plan view (left half) and a cross-sectional view of the rubber washer (right half). Half sectional view of the main part showing another mounting structure for the lower flange plate

  Hereinafter, an embodiment of the seismic isolation bearing according to the present invention will be described with reference to the drawings, assuming that the embodiment is applied to a building such as a building.

[Example 1]
As shown in FIG. 1, the seismic isolation support A includes a lower flange plate 3 bolted to a structure base 1 using bolts 2 and an upper flange plate 5 attached to a structure 4 such as a building. The seismic isolation portion 6 is provided integrally between the upper and lower flange plates 3 and 5 and is configured to have a circular axis and have an axis P when viewed in the vertical direction. For example, as shown in FIG. 1, the seismic isolation portion 6 has a laminated rubber structure in which a plurality of elastic material layers 7 made of rubber or the like and one or more hard plates 8 made of metal plates or the like are alternately stacked one above the other. Is made up of things.

  The attachment part t to the foundation 1 such as concrete of the lower flange plate 3 will be described. As shown in FIGS. 2 and 3, the outer peripheral portion of the lower flange plate 3 is internally fitted with a flanged boss (an example of a restraining member) 11 and a rubber washer (an example of an annular elastic member) 10 fitted on the flange. The bolts 2 are fastened and fixed to the foundation 1 using the bolts 2. The bolt passage hole 9 of the lower flange plate 3 is formed as a stepped hole having a small diameter hole lower part 9a and a larger diameter accommodation hole upper part 9b. The vertical dimension of the accommodation hole upper part 9b is clearly set larger than that of the small diameter hole lower part 9a.

  The metal flanged boss 11, which can also be referred to as a spit spacer, includes a boss portion 11a fitted into the small-diameter hole lower portion 9a (play-fit), and a flange portion 11b having an outer diameter fitted into the accommodation hole upper portion. The vertical dimension is set to be equal to the vertical dimension (thickness) of the lower flange plate 3. The center hole 11 c of the spit spacer 11 is a place through which the shaft portion 2 a of the fixing bolt 2 of the lower flange plate 3 is inserted. The cylindrical rubber washer 10 that is externally fitted (tightly fitted) to the boss portion 11a is set to have an outer diameter that is dimensionable to be internally fitted (tightly fitted) in the accommodation hole upper portion 9b.

  When the spit spacer 11 is tightened (tightened) with the bolt 2 (the state shown in FIG. 2), the boss portion 11a is fitted into the small-diameter hole lower portion 9a and its lower surface 11e is attached to the upper surface 1a of the foundation 1. The flange portion 11b is fitted and accommodated in the upper end portion of the accommodation hole upper portion 9b so that the upper surface 11d thereof is flush with the upper surface 3a of the flange plate 3 while abutting. Thus, the lower flange plate 3 is fitted to the spit-attached spacer 11 that is fixed to the foundation 1 so as to be movable upward. The rubber washer 10 accommodated in the accommodation hole upper portion 9b is incorporated in a state where the bottom surface 12 as the accommodation hole upper portion 9b and the flange portion 11b are slightly compressed up and down to give an initial stress. The flange plate 3, that is, the seismic isolation support A is fixed to the foundation 1 firmly and stably.

  That is, the bolt passage hole 9 of the lower flange plate 3 is formed as a stepped hole having a small-diameter hole lower part 9a and a larger-diameter receiving hole upper part 9b, and a boss part fitted into the small-diameter hole lower part 9a. 11a and a restraining member (salted spacer) 11 that has a flange portion 11b arranged on the upper side of the boss portion 11a in a state of being fitted in the upper portion 9b of the housing hole and can be fitted on the bolt 2, and a boss portion 11a. A rubber washer (annular elastic member) 10 that can be fitted externally and can be fitted in the accommodation hole upper part 9b is provided, and a restraining member 11 in which the boss part 11a is fitted in the small diameter hole lower part 9a is inserted. In the assembled state in which the bolt 2 is fixed to the base 1, the collar 11 b fitted into the accommodation hole upper part 9 b is an outer peripheral part of the lower diameter hole lower part 9 a in the lower flange plate 3 via the annular elastic member 10. Press the bottom surface 12 of the upper part 9b downward It is configured so that.

  Now, when a tensile load (tensile force) is applied to a structure that uses a seismic isolation bearing due to an earthquake, the load is handled by the seismic isolation part in the same way as during compression, but the seismic isolation characteristics are suitable for compression. Therefore, the responsiveness when a tensile load is applied is slow. Therefore, immediately after the tensile load is applied, the components other than the seismic isolation part tend to be heavily loaded. Therefore, conventionally, as means for relaxing and absorbing the stress in the initial stage of the action of the tensile load, means for elastically deforming and compositionally deforming the lower flange plate and the like (Patent Documents 1 and 2), and the lower flange plate via a rubber cushion Means (Patent Document 3) for bolting the foundation was adopted.

  Therefore, when the above-described seismic isolation bearing A according to the present invention is used, a load that lifts the lower flange plate 3 upward in FIGS. The lower flange plate 3 is lifted while the rubber washer 10 is compressed and deformed by the flange 11b of the flanged boss 11 fixed to the foundation 1 and the bottom surface 12 of the upper portion of the accommodation hole. 6 is performed prior to starting the up-down deformation. As a result, since the mounting portion t can partially handle the initial load until the seismic isolation portion 6 fully bears the tensile load, the stress isolation of the tensile load as the seismic isolation support A as a whole. There is an advantage that can be received smoothly and gently without incurring.

  Then, when the tensile load is released, the rubber washer 10 is restored and returned to the original state (the state shown in FIG. 2), so that the lower flange plate 3 is plastically deformed and the parts must be replaced. There is no inconvenience, and the rubber washer 10 is accommodated in the lower flange plate 3 so as not to be seen from the outside, and is excellent in weather resistance. As a result, the seismic isolation bearing A that can cope with a tensile load can be realized to be improved so that it can be maintenance-free while having the necessary functions. Further, the portion excluding the bolt head 2b in the mounting portion t can be configured within the thickness range of the lower flange plate 3, and there is no need to secure a dedicated space for mounting, and the configuration can be made compact. Convenient.

  Since the rubber washer 10 is housed in the lower flange plate 3 in a state of being enclosed in the bolt passage hole 9, a process such as bonding to the lower flange plate 3 using an adhesive or vulcanization bonding is performed. This eliminates the need for this, and can advantageously reduce production costs and assembly man-hours. In addition, the rubber washer 10 functions as a displacement suppressing means even for a load in the left-right direction. Although the bolt hole has a stepped shape, it is only necessary to add a counterbore to the conventional straight hole, which does not significantly increase the cost. Since the rubber washer 10 hardly touches air, there is an advantage that deterioration such as oxidation hardly occurs.

[Another Example]
The attachment part t of the seismic isolation bearing A may have a structure as shown in FIG. That is, the spit spacer 11 is configured to have a structure in which the boss portion 11a and the flange portion 11b are separate from each other and the flange portion 11b is placed on the boss portion 11a. In the assembled state, only the lower end portion of the flange portion 11b is fitted in the accommodation hole upper portion 9b, and the other portion protrudes upward from the upper surface 3a of the lower flange plate 3 to increase the thickness of the rubber washer 10. The structure is thicker than that of the first embodiment.

[Another Example]
The seismic isolation part 6 may be other than a laminated rubber structure such as a lump of rubber. In order to increase the thickness of the rubber washer 10, a seismic isolation bearing device having the lower flange plate 3 in which only the thickness of the bolt passage hole 9 is thicker than the surroundings may be used. The mounting portion t may be a seismic isolation bearing applied to the upper flange plate 5 for the structure 2.

DESCRIPTION OF SYMBOLS 1 Foundation 2 Bolt 3 Lower flange board 3a Upper surface 4 Structure 5 Upper flange board 6 Seismic isolation part 9 Bolt passage hole 9a Small diameter hole lower part 9b Housing hole upper part 10 Annular elastic member 11 Restriction member, flanged boss 11a Boss part 11b 鍔Part 11d upper surface 12 outer peripheral part

Claims (4)

A seismic isolation bearing in which a base isolation part is integrally arranged between the upper and lower sides of a lower flange plate bolted to a foundation for a structure and an upper flange plate attached to the structure,
The lower flange plate has a bolt passage hole formed in a stepped hole having a small diameter hole lower part and a larger diameter accommodation hole upper part, and a boss part and the accommodation hole upper part fitted in the lower diameter hole lower part. A constraining member that has a flange portion disposed on the upper side of the boss portion in a state of being fitted into the boss portion, and can be fitted onto the bolt, and can be fitted onto the boss portion, and can be fitted inside the receiving hole. An annular elastic member that can be fitted, and at least a lower end portion is accommodated in an assembled state in which a restraining member in which the boss portion is fitted in the lower portion of the small-diameter hole is fixed to the foundation with a bolt inserted therethrough. The seismic isolation bearing device configured such that the flange portion fitted in the upper portion of the hole presses the outer peripheral portion of the lower portion of the small-diameter hole in the lower flange plate downwardly through the annular elastic member.   The seismic isolation bearing device according to claim 1, wherein the annular elastic member is made of rubber.   3. The seismic isolation bearing device according to claim 1, wherein in the assembled state, the upper surface of the flange portion and the upper surface of the lower flange plate are set to be in a flush state or substantially flush with each other.   The seismic isolation support according to any one of claims 1 to 3, wherein the restraining member is configured by a single flanged boss integrally including the boss portion and the saliva portion.

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