Seismic isolation system

Abstract

To provide a system that can restore a seismic isolation layer to a state close to its initial condition without using dampers, even if residual deformation occurs in seismic isolation bearings.SOLUTION: A seismic isolation system comprises seismic isolation bearings installed in a seismic isolation layer to support a structure, and coil members formed from shape memory alloy, installed between the structure and a retaining wall forming the seismic isolation layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to seismic isolation systems. [Background technology]

[0002] The seismic isolation damper device described in Document 1 is composed of a rod-shaped seismic isolation body with a superelastic material bonded to the middle part near the base of a rod-shaped high-tensile steel material, the base of which is fixed to a foundation-side metal fitting fixed to the foundation of the structure, and the tip of which is supported by a receiving metal fitting fixed to the structure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Utility Model Application No. 63-81157 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, seismic isolation systems consist of seismic isolation bearings, such as rubber bearings and sliding bearings, installed in the seismic isolation layer to reduce shaking of structures caused by earthquakes, and dampers to ensure attenuation. In this configuration, if residual deformation occurs in the seismic isolation bearings, the dampers and jacks are used to bring the seismic isolation layer closer to its initial state.

[0005] The object of the present disclosure is to bring the seismic isolation layer closer to its initial state without using jacks, even if residual deformation occurs in the seismic isolation bearings of a seismic isolation layer that does not have a damper. [Means for solving the problem]

[0006] The seismic isolation system according to the first aspect is characterized by comprising a seismic isolation bearing provided in the seismic isolation layer and supporting a structure, and a coil-shaped coil member formed of a shape memory alloy and provided between the structure and a retaining wall that forms the seismic isolation layer.

[0007] According to the above-described embodiment, the coil-shaped coil member is formed of a shape memory alloy. Here, an earthquake may cause the structure to shake, resulting in residual deformation in the seismic isolation bearing. In such a case, the coil member can be heated to return it to its initial state. This allows the seismic isolation layer to approach its initial state without using a jack, even if residual deformation occurs in the seismic isolation bearing of a seismic isolation layer that does not have a damper.

[0008] A seismic isolation system according to a second aspect is the seismic isolation system according to the first aspect, characterized in that the seismic isolation bearings are sliding bearings.

[0009] According to the above-mentioned aspect, because sliding bearings are used as seismic isolation bearings, the structure moves with less force than when rubber bearings are used. As a result, even if residual deformation occurs in the sliding bearings of the seismic isolation layer that does not have dampers, the seismic isolation layer can be more easily returned to its initial state than when rubber bearings are used.

[0010] The seismic isolation system according to the third aspect is the seismic isolation system according to the first or second aspect, characterized in that a plurality of the coil members are arranged so as to surround the structure on all sides.

[0011] According to the above aspect, the coil members are arranged so as to surround the structure on all sides, thereby making it possible to restore the seismic isolation layer to an initial state even when there is no space secured below the structure in the seismic isolation layer.

[0012] A seismic isolation system according to a fourth aspect is the seismic isolation system according to the first aspect, characterized in that one end of the coil member is spaced apart from the structure or the retaining wall.

[0013] According to the above aspect, one end of the coil member is spaced apart from the structure or the retaining wall, which can prevent the initial operation of the seismic isolation bearing from being hindered. [Effects of the Invention]

[0014] According to the present disclosure, even if residual deformation occurs in the seismic isolation bearings of a seismic isolation layer that does not have a damper, the seismic isolation layer can be brought closer to its initial state without using a jack. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a front view of a structure in which a seismic isolation system according to a first embodiment of the present disclosure is adopted. [Figure 2] 1 is a cross-sectional view of a structure in which a seismic isolation system according to a first embodiment of the present disclosure is adopted, viewed from above. [Figure 3] (A) (B) (C) Schematic diagrams of a sliding bearing supporting a structure in the seismic isolation system according to the first embodiment of the present disclosure, showing a state in which the structure is not shaking and a state in which the structure is shaking in the width direction. [Figure 4] (A)(B)(C) Schematic diagrams showing a coil member installed between a structure and a retaining wall in the seismic isolation system according to the first embodiment of the present disclosure, showing a state in which the structure is not shaking and a state in which the structure is shaking in the width direction. [Figure 5] 1 is a schematic diagram showing a state in which the compression of the coil member provided between the structure and the retaining wall reaches its limit and the coil member hardens in the seismic isolation system according to the first embodiment of the present disclosure. FIG. [Figure 6] (A)(B)(C) Schematic diagrams showing a coil member installed between a structure and a retaining wall in a seismic isolation system according to the second embodiment of the present disclosure, showing a state in which the structure is not shaking and a state in which the structure is shaking in the width direction. DETAILED DESCRIPTION OF THE INVENTION

[0016] First Embodiment An example of a seismic isolation system according to a first embodiment of the present disclosure will be described with reference to Figures 1 to 5. Note that arrow H shown in each figure indicates the vertical direction, which is the up-down direction of a structure in which the seismic isolation system is adopted, arrow W shown in each figure indicates the width direction of the structure perpendicular to arrow H and also the horizontal direction, and arrow D shown in each figure indicates the depth direction of the structure perpendicular to arrows H and W and also the horizontal direction.

[0017] The drawings used in the following description are all schematic, and the dimensional relationships between elements, ratios, etc. shown in the drawings do not necessarily correspond to the actual ones.

[0018] (Seismic Isolation System 10) The seismic isolation system 10 is a system that prevents the force of an earthquake from being directly transmitted to a structure 100, and is provided in a seismic isolation layer 12 formed between the structure 100 and a foundation structure 120, as shown in Fig. 1. A floor slab 100a is formed at the lower end of the structure 100, and the floor slab 100a is disposed below the ground surface G.

[0019] The foundation structure 120 is box-shaped with an open top and is configured to include a retaining wall 120a that surrounds the floor slab 100a in the width and depth directions, and a foundation slab 120b that covers the floor slab 100a from below. In other words, the seismic isolation layer 12 is formed to include the floor slab 100a, the retaining wall 120a, and the foundation slab 120b.

[0020] The seismic isolation system 10 also includes a sliding bearing 20 that is provided between the foundation slab 120b and the floor slab 100a and supports the structure 100 from below, and a return mechanism 40 that is provided between the retaining wall 120a and the floor slab 100a.

[0021] [Sliding bearing 20] A plurality of sliding bearings 20 are provided lined up in the width and depth directions as shown in Figures 1 and 2. Figure 3(A) shows the initial state of the sliding bearing 20, which includes a sliding plate 22 and a sliding member 24 that can slide along the sliding plate 22.

[0022] In this configuration, when the structure 100 sways in the width direction due to an earthquake, the sliding plate 22 receives the shaking and slides on the sliding member 24, as shown in Figures 3(B) and (C). This prevents the earthquake shaking from being directly transmitted to the structure 100. The same effect is achieved in the depth direction as well.

[0023] [Return mechanism 40] 1 and 2, a plurality of return mechanisms 40 are provided so as to sandwich the floor slab 100a from the width direction or the depth direction. Below, the return mechanisms 40 arranged so as to sandwich the floor slab 100a from the width direction will be described.

[0024] Figure 4(A) shows the initial state of the return mechanism 40, which comprises a coil-shaped coil member 42 extending in the width direction, a base plate 44 attached to one end of the coil member 42, and a base plate 46 attached to the other end of the coil member 42.

[0025] The coil member 42 is a member made of a shape memory alloy formed into a coil shape. Here, a shape memory alloy is an alloy that has the property that when it is deformed below a certain temperature (transformation point), it recovers to its original shape when the deformed piece is heated above that temperature.

[0026] The base plate 44 has a rectangular shape when viewed in the width direction, with the plate thickness direction being the width direction. The base plate 44 has through holes (reference numerals omitted) into which the tip portions of bolts 122, the base ends of which are embedded in the retaining wall 120a, are inserted. The base plate 44 is attached to the retaining wall 120a by screwing nuts 124 onto the bolts 122.

[0027] The base plate 46 has a rectangular shape when viewed from the width direction, with the plate thickness direction being the width direction. The base plate 46 has a through hole (reference numeral omitted) into which the tip portion of a bolt 132 whose base end is embedded in the floor slab 100a is inserted, and the base plate 46 is attached to the floor slab 100a by screwing a nut 134 onto the bolt 132.

[0028] In this configuration, when the structure 100 sways in the width direction due to an earthquake, the coil members 42 expand and contract as shown in Figures 4(B) and 4(C). Note that the same effect is achieved in the depth direction.

[0029] (action) Next, we will explain the operation of the seismic isolation system 10. In the following explanation, we will explain the case where the structure 100 shakes in the width direction due to an earthquake, but the same applies to the case where the structure 100 shakes in the depth direction due to an earthquake.

[0030] When the structure 100 sways in the width direction due to an earthquake, the sliding plate 22 receives the shaking and slides on the sliding member 24, as shown in Figures 3(B) and (C). This prevents the earthquake shaking from being directly transmitted to the structure 100. Furthermore, as shown in Figures 4(B) and (C), the coil member 42 expands and contracts.

[0031] At this point, residual deformation may occur in the sliding bearing 20. For example, as shown in Fig. 3(B), when the structure 100 is swaying to one side in the width direction (to the left in the figure) relative to the initial state (see Fig. 3(A)), residual deformation may occur in the sliding bearing 20 and this state may be maintained.

[0032] In this case, the coil member 42 of the return mechanism 40 arranged on one side of the structure 100 in the width direction is in a contracted state (see FIG. 4(B)), and the coil member 42 of the return mechanism 40 arranged on the other side of the structure 100 in the width direction is in an extended state (see FIG. 4(C)). In this way, the coil member 42 is deformed.

[0033] Here, the coil member 42 is made of a shape memory alloy. Therefore, by heating the deformed coil member 42, the coil member 42 returns to its initial state as shown in Fig. 4(A). As a result, the structure 100 returns to its initial position, and the seismic isolation layer 12 approaches its initial state.

[0034] On the other hand, if the shaking of the structure 100 is greater than expected, the coil member 42 will bottom out (cannot shrink any further) as shown in Figure 5, and will function as a stopper to prevent the structure 100 from coming into contact with the retaining wall 120a.

[0035] (summary) As explained above, in the seismic isolation system 10, even if residual deformation occurs in the sliding bearings 20 of the seismic isolation layer that do not have dampers, the coil members 42 can be heated to return them to their initial state as shown in Figure 4(A). In this way, even if residual deformation occurs in the sliding bearings 20 of the seismic isolation layer that do not have dampers, the seismic isolation layer 12 can be brought closer to its initial state without using a jack. Here, bringing the seismic isolation layer 12 closer to its initial state means that the distances in the width direction and depth direction between the retaining wall 120a and the floor slab 100a can be brought closer to their initial states.

[0036] Furthermore, in the seismic isolation system 10, the coil member 42 is in a coil shape. Therefore, compared to when the coil member 42 is in a rod shape, buckling of the coil member 42 can be suppressed.

[0037] Furthermore, the seismic isolation system 10 uses sliding bearings 20. Therefore, compared to when rubber bearings are used, the structure 100 moves with a smaller force, and the seismic isolation layer 12 can easily return to its initial state.

[0038] Furthermore, in the seismic isolation system 10, the return mechanism 40 (coil member 42) is disposed between the retaining wall 120a and the floor slab 100a, and the return mechanism 40 (coil member 42) is disposed so as to surround the floor slab 100a from all four sides. This allows the seismic isolation layer 12 to be brought close to its initial state even if no space is secured between the floor slab 100a and the foundation slab 120b.

[0039] Second Embodiment An example of a seismic isolation system according to a second embodiment of the present disclosure will be described with reference to Fig. 6. Note that, with regard to the second embodiment, differences from the first embodiment will be mainly described.

[0040] (composition) 6(A) shows the initial state of the return mechanism 90 of the seismic isolation system 60 according to the second embodiment. The return mechanism 90 includes a coil member 42 that is coil-shaped and extends in the width direction, a base plate 44 attached to one end of the coil member 42, and a base plate 96 attached to the other end of the coil member 42.

[0041] The base plate 96 has a rectangular shape when viewed in the width direction, with the plate thickness direction being the width direction. The base plate 96 is spaced apart from the floor slab 100a in the width direction in which the coil member 42 extends. In other words, in the initial state, the coil member 42 of the return mechanism 90 is attached to the retaining wall 120a and spaced apart from the floor slab 100a.

[0042] (action) In this configuration, when the structure 100 sways in the width direction due to an earthquake, the coil members 42 expand and contract as shown in Figures 6(B) and 6(C). Note that the same effect is achieved in the depth direction as well.

[0043] Here, in the initial state, the base plate 96 is spaced apart from the floor slab 100a in the width direction in which the coil member 42 extends. In other words, when the structure 100 begins to shake, the floor slab 100a and the base plate 96 are spaced apart. Then, when the structure 100 shakes by a predetermined amount or more, the base plate 96 and the floor slab 100a come into contact with each other, causing the coil member 42 to expand and contract.

[0044] (summary) In this way, in the seismic isolation system 60, when the structure 100 shakes by a predetermined amount or more, the base plate 96 and the floor slab 100a come into contact with each other, causing the coil member 42 to expand and contract. This makes it possible to prevent the initial operation of the sliding bearing 20 from being hindered.

[0045] Although the present disclosure has been described in detail with respect to a specific embodiment, it will be apparent to those skilled in the art that the present disclosure is not limited to such an embodiment, and that various other embodiments are possible within the scope of the present disclosure. For example, in the above embodiment, the sliding bearing 20 is used as the seismic isolation bearing, but other seismic isolation bearings such as rolling bearings or rubber bearings may also be used. In this case, the effect achieved by using the sliding bearing 20 as the seismic isolation bearing will not be achieved.

[0046] Furthermore, in the above embodiment, a plurality of coil members 42 (return mechanisms 40, 90) are arranged to surround the structure 100 on all sides, but they do not necessarily have to be arranged to surround the structure 100 on all sides. In this case, however, the effect achieved by arranging the coil members 42 to surround the structure 100 on all sides will not be achieved.

[0047] In the second embodiment, the coil member 42 of the return mechanism 90 is initially attached to the retaining wall 120a and spaced apart from the floor slab 100a. However, the coil member 42 may also be initially attached to the floor slab 100a and spaced apart from the retaining wall 120a. [Explanation of symbols]

[0048] 10 Seismic isolation system 12 Seismic isolation layer 20 Sliding bearing 42 Coil material 100 structures 120a Retaining wall

Claims

1. a seismic isolation bearing provided in the seismic isolation layer and supporting the structure; a coil member formed of a shape memory alloy and disposed between the structure and a retaining wall that forms the seismic isolation layer; A seismic isolation system equipped with:

2. Seismic isolation bearings are sliding bearings. The seismic isolation system according to claim 1 .

3. A plurality of the coil members are arranged so as to surround the structure from all sides. The seismic isolation system according to claim 1 or 2, comprising:

4. One end of the coil member is spaced apart from the structure or the retaining wall. The seismic isolation system according to claim 1 .

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