Lower pca foundation of seismic isolator, and joint structure between lower pca foundation of seismic isolator and concrete skeleton

Abstract

To provide a lower PCa foundation of a seismic isolator that can minimize overall dimensions as much as possible and has excellent on-site installation properties, and to provide a joint structure between a lower PCa foundation of a seismic isolator and a concrete skeleton that has excellent on-site workability.SOLUTION: A lower PCa foundation 70 of a seismic isolator has a concrete body 10 comprising an upper surface 11 on which a seismic isolator 200 is placed and a lower surface 12 facing a concrete skeleton 80. Embedded jigs 20, 20' are embedded inside the concrete body 10. The embedded jigs 20, 20' comprise: a cap nut 30 facing the upper surface 11 and having a first threaded hole 33 at one end into which a mounting bolt 250 extending downward from the seismic isolator 200 side is screwed; and a sleeve 40 which faces the lower surface 12, which is directly or indirectly connected to the cap nut 30, and through which a joint bar 90 protruding upward from the concrete skeleton 80 is inserted.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a lower PCa foundation of a seismic isolation device and a joint structure between the lower PCa foundation of a seismic isolation device and a concrete body. [Background technology]

[0002] In the construction of buildings using seismic isolation devices, a base plate is placed while adjusting the level, leaving a gap between it and the top surface of the concrete structure (including reinforced concrete floor slabs, slabs, footings, etc.), a formwork is placed around the base plate on the top surface of the concrete structure, concrete is poured inside the formwork, and in some cases, non-shrink mortar is further poured above the concrete to prevent the occurrence of voids, thereby constructing a lower concrete foundation made of these cement-based materials between the concrete structure and the base plate. The reason for installing a base plate that directly supports the seismic isolation device in this way is that the top surface of the concrete structure has no small amount of surface unevenness, and it is difficult to achieve a highly accurate horizontal position for the seismic isolation device when it is installed directly on the top surface of the concrete structure.

[0003] However, the series of construction steps at the construction site, such as placing a base plate while leaving a gap above the concrete structure to adjust the level, setting up formwork around it, pouring cement-based material inside the formwork, waiting for it to develop strength before removing the formwork, takes time and effort. Therefore, to solve these issues inherent in the on-site construction of lower concrete foundations, a lower PCa (PreCast) foundation is sometimes used, in which the lower concrete foundation is manufactured in a factory, transported to the site, and connected to the concrete structure with anchor bolts.

[0004] For example, Patent Document 1 proposes a foundation block made of precast concrete. This foundation block includes a bottom surface, an upper surface facing the bottom surface, an outer peripheral surface connecting the bottom surface and the upper surface at their respective outer peripheral edges, a receiving portion that opens on the bottom surface and extends to the inside of the foundation block, a communication hole that opens on the outer peripheral surface, a plurality of nuts that open on the upper surface and extend toward the bottom surface, and an anchor bolt that is screwed onto each of the nuts and extends from the lower end of the nut toward the bottom surface. The receiving portions are provided at a plurality of locations along the outer peripheral edge of the bottom surface, and the receiving portions and the communication holes communicate with each other, so that reinforcing bars arranged inside the foundation block extend from the upper end of the receiving portion into the receiving portion. The receiving portions and the communication holes form an embedded sleeve that is embedded in the foundation block. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-101045 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the precast concrete foundation block described in Patent Document 1, an embedded sleeve with a receiving portion through which a first reinforcing bar protruding upward from the top surface of the foundation is inserted is further provided around a number of nuts provided on the foundation block which is joined to the seismic isolation device by anchor bolts.

[0007] In other words, when viewed in plan, the foundation block has an embedded sleeve for connecting to the foundation with the first reinforcing bar arranged inside the rectangular outer line around multiple nuts for bolting to the seismic isolation device, which are arranged at intervals along the central circular line.This means that two types of nuts and embedded sleeves are arranged at separate positions in plan, which tends to increase the planar dimensions of the foundation block.

[0008] In addition, since the seismic isolation device and foundation block are joined by anchor bolts, and considering that anchor bolts are generally required to have a minimum required embedded length, the thickness of the foundation block tends to be large, which, combined with the tendency for the planar dimensions to become larger as mentioned above, poses the problem of the overall dimensions of the foundation block becoming larger.

[0009] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a lower PCa foundation for a seismic isolation device that can have overall dimensions as small as possible and is easy to install on site, and a joint structure between the lower PCa foundation of the seismic isolation device and a concrete body that is easy to work on site. [Means for solving the problem]

[0010] In order to achieve the above object, one embodiment of the lower PCa foundation of the seismic isolation device according to the present invention is as follows: A lower PCa foundation of a seismic isolation device having a concrete body with an upper surface on which the seismic isolation device is placed and a lower surface facing the concrete structure, A embedding jig is embedded inside the concrete body, The embedding jig is a cap nut having a first threaded hole at one end, facing the upper surface, into which an attachment bolt extending downward from the seismic isolation device is screwed; The present invention is characterized in that it is provided with a sleeve facing the underside, connected directly or indirectly to the cap nut, and through which a reinforcing bar protruding upward from the concrete structure is inserted.

[0011] According to this aspect, the buried jig is composed of a cap nut that connects the seismic isolation device and the concrete body via a mounting bolt, and a sleeve that connects the concrete body and the concrete body via a plug, and since the cap nut and the sleeve are in the same position in a plan view, the plan dimensions of the lower PCa foundation can be made as small as possible. Furthermore, since the seismic isolation device and the lower PCa foundation are connected by a mounting bolt instead of an anchor bolt, there is no requirement for a minimum embedding length like with anchor bolts, so the thickness of the lower PCa foundation can be suppressed from becoming thick, and together with the above-mentioned plan dimensions being made as small as possible, the overall dimensions of the lower PCa foundation can be made as small as possible. In addition, since the overall dimensions are as small as possible, the structure has excellent transportability and handling at the site, which contributes to improving the workability when constructing the joint structure of the lower PCa foundation of the seismic isolation device and the concrete body at the site.

[0012] Here, "the cap nut and the sleeve are directly or indirectly connected" includes a form in which the end of the cap nut and the end of the sleeve are directly connected by welding or the like, and a form in which the cap nut and the sleeve are indirectly connected by reinforcing bars or the like. In addition, examples of the "insertion bars" include anchor bolts and deformed reinforcing bars. Furthermore, examples of the "mounting bolts" include high-strength bolts.

[0013] In addition, another aspect of the lower PCa foundation of the seismic isolation device according to the present invention is as follows: The cap nut and the sleeve are welded together, or one is screwed onto the other.

[0014] According to this aspect, since the cap nut and the sleeve are directly connected by welding or screwing, the two are connected without using any other members, and therefore an embedding jig with a simpler configuration can be formed. Here, in a form in which both are screwed together, one of the end of the cap nut and the end of the sleeve is a female thread and the other is a male thread, and the male thread is screwed into the female thread.

[0015] In another embodiment of the lower PCa foundation of the seismic isolation device according to the present invention, The other end of the cap nut has a second threaded hole, The embedding jig is characterized in that it further includes one of a threaded rebar, a threaded deformed rebar, or an anchor bolt, one end of which is screwed into the second threaded hole and the other end of which is inserted into the sleeve.

[0016] According to this embodiment, one end of a threaded reinforcing bar, a threaded deformed reinforcing bar, or an anchor bolt is screwed into a second threaded hole provided at the other end of the cap nut, and the other end is inserted into the sleeve to indirectly connect the cap nut and the sleeve, thereby allowing these connecting members to form an embedding jig that can be freely adjusted in height.

[0017] Here, the sleeve will be filled with grout in a later process, and an indirect connection structure between the cap nut and the sleeve will be formed when the filled grout has hardened.

[0018] In addition, another aspect of the lower PCa foundation of the seismic isolation device according to the present invention is as follows: The present invention is characterized in that a tightening nut is screwed onto any one of the threaded reinforcing bar, the deformed reinforcing bar, and the anchor bolt, and presses the cap nut.

[0019] According to this aspect, in a configuration in which the bag nut and sleeve are indirectly connected via a threaded reinforcing bar or the like, the tightening nut is screwed onto the threaded reinforcing bar or the like and presses the bag nut, thereby increasing the degree of fixation of the threaded reinforcing bar, which is an axial member, to the bag nut.

[0020] In addition, another aspect of the lower PCa foundation of the seismic isolation device according to the present invention is as follows: A plurality of the embedding jigs are embedded inside the concrete body, The sleeve of one of the embedding jigs is provided with an injection hole for injecting grout and a discharge hole for discharging the grout filled inside the sleeve, and a sealing plug having an air vent groove is attached to the discharge hole, The sleeve of the embedding jig is also characterized in that only the discharge hole is provided, and the sealing plug is attached to the discharge hole.

[0021] According to this aspect, a plurality of embedding jigs are embedded inside a concrete body, and a sealing plug having an air vent groove is attached to the sleeve of one of the embedding jigs, which is provided with an injection hole for injecting grout and a discharge hole for discharging the grout filled inside, and a sealing plug having an air vent groove is attached, and the sleeves of the other embedding jigs are provided with only a discharge hole and a sealing plug is attached, so that grout injected from one injection hole can be supplied to the sleeves of all the embedding jigs. Furthermore, the grout can be densely filled into the sleeves while air, excess water, etc. are discharged from the air vent groove of the sealing plug in the discharge hole provided in the sleeve of each embedding jig.

[0022] In addition, one embodiment of the joint structure between the lower PCa foundation of the seismic isolation device and the concrete frame according to the present invention is as follows: A joint structure between the lower PCa foundation of the seismic isolation device and the concrete skeleton, The grout injected from the injection hole is filled into the gap between the concrete body and the concrete structure, and further filled inside each sleeve, thereby integrating the lower PCa foundation and the concrete structure.

[0023] According to this embodiment, grout is injected from the injection hole of the sleeve of one of the multiple embedding jigs, and is filled into the gap between the concrete structure and the concrete body, and then further filled into the sleeves of each embedding jig that communicate with the gap.This, combined with the fact that the overall dimensions of the lower PCa foundation are as small as possible, makes it possible to construct the joint structure with excellent workability. Effect of the Invention

[0024] As can be understood from the above explanation, according to the lower PCa foundation of the seismic isolation device of the present invention, and the joint structure between the lower PCa foundation of the seismic isolation device and a concrete body, it is possible to make the overall dimensions as small as possible, and to provide the lower PCa foundation of the seismic isolation device which is excellent in on-site installation properties, and the joint structure between the lower PCa foundation of the seismic isolation device and a concrete body which is excellent in on-site workability. [Brief description of the drawings]

[0025] [Figure 1] FIG. 2 is a plan view of an example of a lower PCa foundation according to an embodiment. [Diagram 2] FIG. 2 is a view taken along the line II-II of FIG. 1, and is a longitudinal cross-sectional view taken at the center of an example of a lower PCa foundation. [Diagram 3] FIG. 2 is a vertical cross-sectional view of an example of a joint structure between a lower PCa foundation and a concrete body according to an embodiment of the present invention. [Figure 4] 1 is a vertical cross-sectional view showing an example of a joint structure between a lower PCa foundation and a concrete body according to an embodiment of the present invention, in which an example of a seismic isolation device is attached. [Diagram 5] A vertical cross-sectional view of another example of a lower PCa foundation according to an embodiment. [Figure 6] 13 is a vertical cross-sectional view of yet another example of a lower PCa foundation according to an embodiment. FIG. [Figure 7] 13 is a vertical cross-sectional view of yet another example of a lower PCa foundation according to an embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, an example of the lower PCa foundation of the seismic isolation device and the joint structure between the lower PCa foundation of the seismic isolation device and the concrete skeleton will be described with reference to the attached drawings. Note that in this specification and the drawings, substantially the same components are designated by the same reference numerals to avoid redundant explanations.

[0027] [The lower PCa foundation according to the embodiment and the joint structure between the lower PCa foundation and the concrete structure] An example of a lower PCa foundation and a joint structure between the lower PCa foundation and a concrete skeleton according to the embodiment will be described with reference to Fig. 1 to Fig. 7. Fig. 1 is a plan view of the example of the lower PCa foundation according to the embodiment, Fig. 2 is a vertical cross-sectional view taken along the line II-II in Fig. 1, in which the example of the lower PCa foundation is cut at the center. Fig. 3 is a vertical cross-sectional view of an example of the joint structure between the lower PCa foundation and a concrete skeleton according to the embodiment, and Fig. 4 is a vertical cross-sectional view showing a state in which an example of a seismic isolation device is attached to the example of the joint structure between the lower PCa foundation and a concrete skeleton according to the embodiment.

[0028] As shown in Figures 1 and 2, the lower PCa foundation 70 has a concrete body 10 that is square in plan view (an example of a rectangle), and is formed by burying multiple (12 in the illustrated example) embedded jigs 20, 20' inside the concrete body 10.

[0029] More specifically, due to the difference in the configuration of the sleeves 40, 40' provided on the embedding jigs 20, 20', one embedding jig 20 and multiple other embedding jigs 20' (11 in the illustrated example) are buried at equal intervals on a circular line inside the concrete body 10.

[0030] The concrete body 10 is a square in plan view with each side having a length of t1, a horizontally long cube with a thickness of t2, and has a top surface 11, a bottom surface 12, and four side surfaces 13, and is a block of reinforced concrete with reinforcing bars (not shown) arranged inside.

[0031] The lower PCa foundation 70 is a precast product that is manufactured in a factory, transported to the site, and installed above the concrete structure at the site, and therefore the flatness of the upper surface 11 on which the seismic isolation device is placed is guaranteed. This eliminates the need for a base plate that is installed to ensure flatness when constructing the lower concrete foundation at the site, and further eliminates the problem of the time and effort required in the series of construction steps of installing the base plate, installing a formwork around it, pouring a cement-based material inside the formwork, waiting for the strength to develop before removing the formwork, thereby allowing for good workability (installability) at the site.

[0032] As shown in Figure 2, the embedding jig 20 is a linear jig having a cap nut 30 facing the upper surface 11 of the concrete body 10, a sleeve 40 facing the lower surface 12 of the concrete body 10, and a screw bar 50 connecting the cap nut 30 and the sleeve 40.

[0033] Here, the member connecting the cap nut 30 and the sleeve 40 may be a deformed bar, an anchor bolt, or the like, in addition to the threaded reinforcing bar 50 .

[0034] One end of the cap nut 30 has a first threaded hole 33 facing the upper surface 11, and this first threaded hole 33 is adapted to receive an attachment bolt 250 (see Figure 4) extending downward from the seismic isolation device side.

[0035] On the other hand, the lower surface 44 of the sleeve 40 faces the lower surface 12, and an insert bar 90 (see FIG. 4) protruding upward from the upper surface 81 of the concrete structure 80 is inserted through it. The upper surface 42 of the sleeve 40 abuts against the lower surface 31 of the cap nut 30.

[0036] The other end of the cap nut 30 is provided with a second threaded hole 35 , into which the upper part of the threaded reinforcing bar 50 is screwed, and the lower part of the threaded reinforcing bar 50 is inserted into the inside of the sleeve 40 .

[0037] When the lower PCa foundation 70 transported to the site is joined to the concrete body 80 via grout, the filled grout fills the inside of the sleeve 40 and hardens in a state where the grout is embedded below the screw reinforcing bar 50 inserted into the inside of the sleeve 40, thereby integrating each component part of the embedding jig 20.

[0038] In this manner, in the illustrated embedding jig 20 , the cap nut 30 and the sleeve 40 are indirectly connected via the threaded reinforcing bar 50 .

[0039] The sleeve 40 is provided with an injection hole 45 for injecting grout and a discharge hole 46 for discharging the grout filled inside the sleeve 40, and a sealing plug 48 equipped with an air vent groove (not shown) is attached to the discharge hole 46. This sealing plug 48 has a known structure that completely closes the discharge hole 46 when a certain amount of grout has been discharged.

[0040] On the other hand, the basic configuration of the embedding jig 20 ′ is similar to that of the embedding jig 20 , but differs from the embedding jig 20 in that the sleeve 40 ′ does not have the injection hole 45 , but only has the discharge hole 46 .

[0041] 3, a plurality of (12 in this example) insert bars 90 protrude upward from an upper surface 81 of a concrete skeleton 80. Here, the insert bars 90 may be threaded reinforcing bars, deformed reinforcing bars, anchor bolts, or the like.

[0042] The upper parts of the insert bars 90 protruding upward from the upper surface 81 of the concrete body 80 are inserted into the sleeves 40, 40' of the corresponding embedding jigs 20, 20', and the lower PCa foundation 70 is installed above the concrete body 80 with a gap G between the upper surface 81 of the concrete body 80 and the lower surface 12 of the lower PCa foundation 70. For example, a spacer (not shown) that can ensure the gap G is installed on the upper surface 81, and the lower surface 12 of the concrete body 10 of the lower PCa foundation 70 is placed on the spacer.

[0043] Next, a grout sealing frame (not shown) is placed around the gap G, and grout 85 is filled in through the injection hole 45 of the embedding jig 20, thereby filling the entire gap G with grout 85.

[0044] After the entire gap G has been filled with grout 85, the grout 85 is filled into the sleeves 40, 40' of each embedding jig 20, 20' that communicate with the gap G, air and excess water are discharged from the air vent grooves of the sealing plugs 48 that seal the discharge holes 46 of each sleeve 40, 40', and finally, the grout 85 is discharged, thereby ensuring that the entire gap G and each sleeve 40, 40' have been densely filled with grout 85.

[0045] Here, the illustrated example shows a configuration in which only the sleeve 40 of one embedding jig 20 has a grout injection hole 45, and the sleeve 40' of the other embedding jig 20' does not have an injection hole 45, but from the standpoint of grout filling property and filling efficiency, grout injection holes may also be provided in all or some of the sleeves of the other embedding jig.

[0046] As the grout filled in the gap G and each sleeve 40, 40' hardens, in each embedment jig 20, 20', the screw reinforcing bar 50 inserted into the sleeve 40, 40' is connected to the sleeve 40, 40' via the grout 85, thereby integrating each component part of the embedment jig 20, 20'.

[0047] Furthermore, the upper part of the insert bar 90 is connected to the sleeves 40, 40' via grout 85, and the lower surface 12 of the concrete body 10 is connected to the upper surface 81 of the concrete body 80 via grout 85, thereby forming a joint structure 100 between the lower PCa foundation of the seismic isolation device and the concrete body.

[0048] After the joint structure 100 is formed, as shown in FIG. 4, the seismic isolation device 200 is installed on the upper surface 11 of the concrete body 10, and the two are joined together via mounting bolts 250.

[0049] Here, the illustrated seismic isolation device 200 has a laminated rubber body 210, an upper flange 220 above the laminated rubber body 210 which is joined to an upper concrete foundation (not shown), and a lower flange 230 below the laminated rubber body 210.

[0050] In the lower flange 230, bolt holes 232 are provided at positions corresponding to the first threaded holes 33 of each of the cap nuts 30 of the multiple (12 in the illustrated example) embedded jigs 20, 20' shown in Figure 1, and the seismic isolation device 200 is installed by aligning the bolt holes 232 corresponding to each of the first threaded holes 33, and the seismic isolation device 200 is installed on the lower PCa foundation 70 by screwing a mounting bolt 250 made of a high-strength bolt into the interconnected first threaded holes 33 and bolt holes 232.

[0051] The upper flange 220 also has bolt holes 222 so that the two can be joined to an upper concrete foundation (not shown) via mounting bolts such as high-strength bolts.

[0052] Here, the illustrated example of the seismic isolation device 200 includes a form in which a lead plug extending in the vertical direction is inserted into the center of the laminated rubber body, a form formed from high-damping rubber, etc. In addition to the form formed from such a laminated rubber body, the seismic isolation device may be a seismic isolation device of other structure such as a sliding seismic isolation device including a planar sliding type seismic isolation device or a spherical sliding type seismic isolation device.

[0053] According to the joining structure 100 in which the lower PCa foundation 70 in the illustrated example is joined to the concrete body 80, the lower PCa foundation 70 is equipped with a linear embedded jig 20, 20' consisting of a cap nut 30 that joins the seismic isolation device 200 and the concrete body 10 via an attachment bolt 250, and a sleeve 40, 40' that joins the concrete body 80 and the concrete body 10 via a reinforcing bar 90, and since the cap nut 30 and the sleeve 40, 40' are in the same position when viewed in a plane, the planar dimension (area t1 x t1) of the lower PCa foundation 70 can be made as small as possible.

[0054] Furthermore, by joining the seismic isolation device 200 and the lower PCa foundation 70 with mounting bolts 250 such as high-strength bolts instead of anchor bolts, there is no requirement for a minimum embedding length as with anchor bolts, so the thickness t2 of the lower PCa foundation 70 can be prevented from becoming thick, and coupled with the fact that the planar dimensions can be made as small as possible, the overall dimensions of the lower PCa foundation 70 can be made as small as possible. Therefore, the structure has excellent transportability and handleability on site, which contributes to improving workability when constructing the joint structure 100 on site.

[0055] In addition, since the seismic isolation device 200 and the lower PCa foundation 70 are not joined by anchor bolts, there is no need to consider cone-shaped failure caused by the pull-out force acting on the anchor bolts in terms of the failure mode of the lower PCa foundation 70 during an earthquake at the design stage. In other words, it is sufficient to consider the axial yield of the embedded jigs 20, 20' joined to the mounting bolts 250 and the bond failure with the concrete body 10 as the failure mode.

[0056] Furthermore, grout 85 injected from the injection hole 45 of the sleeve 40 of one of the multiple embedding jigs 20, 20' is filled into the gap G between the concrete structure 80 and the concrete body 10, and is further filled into the sleeves 40, 40' of each embedding jig 20, 20' that communicate with the gap G. This, combined with the overall dimensions of the lower PCa foundation 70 being as small as possible, makes it possible to construct the joint structure 100 with excellent workability.

[0057] Next, modified examples of the lower PCa foundation according to the embodiment will be described with reference to Figs.

[0058] The lower PCa foundation 70A shown in FIG. 5 differs from the lower PCa foundation 70 in that it has embedded jigs 20A, 20A′ further equipped with tightening nuts 60 that screw into the threaded reinforcing bars 50.

[0059] The tightening nut 60 that screws into the threaded reinforcing bar 50 is interposed between the lower surface 31 of the bag nut 30 and the upper surface 42 of the sleeve 40 while pressing the lower surface 31 of the bag nut 30, thereby increasing the degree of fixation of the threaded reinforcing bar 50, which is the axial member, to the bag nut 30.

[0060] On the other hand, the lower PCa foundation 70B shown in Figure 6 differs from the lower PCa foundation 70, 70A in that the embedding jig 20B, 20B' has a sleeve 40A, 40A' having a third threaded hole 47 into which the lower part of the screw reinforcing bar 50 screws into.

[0061] According to this embodiment, the respective components of the embedding jigs 20B, 20B' can be integrated together, for example, at the factory shipping stage before the sleeves 40A, 40A' are filled with grout.

[0062] Furthermore, the lower PCa foundation 70C shown in FIG. 7 differs from the lower PCa foundations 70, 70A, and 70B in that the lower surface 31 of the cap nut 30 and the upper surfaces 42 of the sleeves 40, 40' are directly joined by welding.

[0063] According to this embodiment, the threaded reinforcing bar 50 for connecting the cap nut 30 and the sleeve 40, 40' and the like can be eliminated, so that the embedding jigs 20C, 20C' can be manufactured with a reduced number of parts.

[0064] In addition, in addition to the welded joint shown in the figure, the form in which the bag nut 30 and the sleeve 40, 40' are directly connected may be a form in which one of the bag nut 30 and the sleeve 40, 40' has a female thread and the other has a male thread, and the two are screwed together.

[0065] The present invention is not limited to the configurations shown here, and may be implemented in other embodiments in which other components are combined with the configurations and the like set forth in the above embodiments. In this regard, the present invention may be modified without departing from the spirit of the present invention, and may be appropriately determined according to the application form. [Explanation of symbols]

[0066] 10: Concrete body 11:Top surface 12: Bottom surface 13: Side 20, 20', 20A, 20A', 20B, 20B', 20C, 20C': Buried jig 30, 30A: Cap nut 31: Bottom surface 33: First threaded hole 35: Second threaded hole 40, 40', 40A, 40A': Sleeve 42:Top surface 44: Bottom surface 45: Injection hole 46:Discharge hole 47: 3rd threaded hole 48: Sealing plug 50: Screw rebar 60: Clamping nut 70, 70A, 70B, 70C: Lower PCa foundation (lower PCa foundation of seismic isolation device) 80: Concrete structure 81:Top surface 85: Grout 90: Insert bar (screw rebar) 100: Joint structure (joint structure between the lower PCa foundation of the seismic isolation device and the concrete structure) 200: Seismic isolation device 210: Laminated rubber body 220: Top flange 222: Bolt hole 230: Lower flange 232: Bolt hole 250: Mounting bolt G: Gap

Claims

1. A lower PCa foundation of a seismic isolation device having a concrete body with an upper surface on which the seismic isolation device is placed and a lower surface facing a concrete skeleton, A embedding jig is embedded inside the concrete body, The embedding jig is a cap nut having a first threaded hole at one end, into which a mounting bolt extending downward from the seismic isolation device is screwed, the cap nut facing the upper surface; A lower PCa foundation of a seismic isolation device, characterized in that it is provided with a sleeve facing the underside, connected directly or indirectly to the cap nut, and through which a reinforcing bar protruding upward from the concrete body is inserted.

2. The lower PCa foundation of the seismic isolation device according to claim 1, characterized in that the cap nut and the sleeve are welded together or one is screwed into the other.

3. The other end of the cap nut has a second threaded hole, The lower PCa foundation of the seismic isolation device described in claim 1, characterized in that the embedding jig further comprises one of a threaded reinforcing bar, a threaded deformed reinforcing bar, or an anchor bolt, one end of which is screwed into the second threaded hole and the other end of which is inserted into the sleeve.

4. The lower PCa foundation of the seismic isolation device according to claim 3, characterized in that a tightening nut is screwed onto any one of the threaded reinforcing bar, the deformed reinforcing bar, and the anchor bolt to press the cap nut.

5. A plurality of the embedding jigs are embedded inside the concrete body, The sleeve of one of the embedding jigs is provided with an injection hole for injecting grout and a discharge hole for discharging the grout filled inside the sleeve, and a sealing plug having an air vent groove is attached to the discharge hole, The lower PCa foundation of a seismic isolation device according to any one of claims 2 to 4, characterized in that the sleeve of the other embedded jig is provided with only the discharge hole, and the sealing plug is attached to the discharge hole.

6. A joint structure between the lower PCa foundation of the seismic isolation device according to claim 5 and the concrete skeleton, A joint structure between the lower PCa foundation and the concrete body of a seismic isolation device, characterized in that grout injected from the injection hole is filled into the gap between the concrete body and the concrete body, and further filled inside each sleeve, thereby integrating the lower PCa foundation and the concrete body.

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