Construction methods for seismic isolation foundations

Abstract

To provide a method for constructing seismic isolation foundations that can prevent the construction of seismic isolation foundations in which an air pocket exists between the lower surface of the base plate and the top surface of the foundation concrete at a rate that does not meet the standard value. [Solution] A method for constructing a seismic isolation foundation 100 to which a seismic isolation device 200 is attached, comprising: a preparation step of setting up formwork 10, setting up a frame-shaped plate 30 on the inside of the upper part of formwork 10, and setting up a top plate 40 equipped with filling holes 44 and air vent holes 46 on top of the frame-shaped plate 30; a concrete filling step of filling concrete C through the filling holes 44 and filling concrete C up to the bottom surface 41 of the top plate 40; and a curing and demolding step of curing the concrete to form a foundation concrete 80, removing the top plate 40, demolding the formwork 10, and constructing a seismic isolation foundation 100 in which the frame-shaped plate 30 equipped with anchor bolts 35 is embedded in the foundation concrete 80.

Description

Technical Field

[0001] The present invention relates to a method for constructing a seismic isolation foundation.

Background Art

[0002] A seismic isolation foundation that supports various forms of seismic isolation devices such as laminated rubber devices and sliding devices generally has a configuration in which a base plate is buried at the top end of columnar or rectangular parallelepiped foundation concrete. The base plate is provided with a filling hole for filling concrete inside the formwork below it and bolt holes for bolt-joining the lower plate of the seismic isolation device. Further, anchor bolts are attached to its lower surface and are embedded in the constructed foundation concrete. The anchor bolts are members that transmit these external forces to the foundation concrete while resisting the pulling force and shear force acting through the seismic isolation device.

[0003] When the flatness of the top end of the foundation concrete to be constructed (manufactured) is not good, the weight (vertical load) of the superstructure acting from the seismic isolation device does not act evenly over the entire area of the foundation concrete. Therefore, the above-described configuration in which a flat base plate is provided at the top end of the seismic isolation device is generally adopted, and the seismic isolation device is attached to the surface of the base plate.

[0004] By the way, in the construction of installing a formwork at the site, installing a base plate at a predetermined height position inside the formwork, and filling concrete below it through the filling hole of the base plate, when the concrete hardens in a state where an air pocket has occurred on the lower surface of the base plate, the lower surface of the base plate and the top end of the foundation concrete do not contact each other in the area of the air pocket, and the vertical load described above cannot be evenly applied to the entire area of the lower surface of the base plate at the top end of the foundation concrete. And this can lead to uneven distribution of the vertical load acting on the top end of the foundation concrete, and in areas where excessive compressive stress occurs in the foundation concrete, it may lead to crushing of the concrete.

[0005] Therefore, in practice, mock-up tests are conducted prior to actual construction to confirm that no air pockets occur, or that the air pockets are below an acceptable percentage (for example, 20% or less of the entire base plate, or 10% or less), and that these criteria are met before actual construction is carried out. However, since it is uncertain whether all of the multiple seismic isolation foundations to be constructed are built in the same way as the test specimens in the mock-up tests, it is actually uncertain whether all of the multiple seismic isolation foundations to be constructed meet the criteria.

[0006] Therefore, a construction method for seismic isolation foundations is desired that can prevent the construction of seismic isolation foundations in which an air pocket exists between the lower surface of the base plate and the top surface of the foundation concrete that does not meet the standard value.

[0007] Here, Patent Document 1 proposes a method for filling the lower part of the base plate of a seismic isolation device with a filler material. This filling method involves arranging a formwork for constructing a seismic isolation foundation, installing a base plate having injection holes at the upper end of the space defined by the formwork, pouring preliminary concrete into the formwork to create a space for filling the filler material between the upper surface of the preliminary concrete and the lower surface of the base plate, then installing a hopper support stand straddling the formwork, and opening an on / off valve provided at the bottom of the hopper, thereby supplying a certain amount of filler material stored in the hopper supported by the hopper support stand from the filler material discharge port at the lower end of the hopper through the injection holes in the base plate to the space for filling the filler material. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Patent No. 5178479 [Overview of the project] [Problems that the invention aims to solve]

[0009] Even in the method of filling the lower part of the base plate of a seismic isolation device described in Patent Document 1, since the base plate is embedded in the top surface of the concrete, it is not possible to confirm that there are no air pockets below the base plate that do not meet the standard value.

[0010] This invention has been made in view of the above problems, and aims to provide a method for constructing a seismic isolation foundation that can prevent the construction of a seismic isolation foundation in which an air pocket exists between the lower surface of the base plate and the top surface of the foundation concrete at a rate that does not meet the standard value. [Means for solving the problem]

[0011] To achieve the above objective, one aspect of the construction method for seismic isolation foundations according to the present invention is: A method for constructing a seismic isolation foundation, on which seismic isolation devices are installed, A preparatory step involves setting up a frame-shaped formwork, installing a frame-shaped plate inside the upper part of the formwork, where the frame-shaped plate is equipped with bolt holes for bolting the seismic isolation device, and anchor bolts are directly or indirectly attached to its lower surface, and then installing a top plate equipped with filling holes and air vents on top of the frame-shaped plate. A concrete filling step is to fill the inside of the formwork with concrete through the filling holes and fill the concrete up to the lower surface of the top plate, The invention is characterized by comprising a curing and demolding step, in which the aforementioned concrete is cured to form the foundation concrete, the top plate is removed, the formwork is demolded, and the seismic isolation foundation is constructed in which the frame-shaped plate equipped with the anchor bolts is embedded in the foundation concrete.

[0012] According to this embodiment, a frame-shaped plate is installed inside the upper part of a frame-shaped formwork, a top plate is installed on top of the frame-shaped plate with anchor bolts directly or indirectly attached to its lower surface and equipped with filling holes and air vents, concrete is filled into the inside of the formwork, and after curing, the foundation concrete is formed, and then the top plate is removed to construct the seismic isolation foundation. This eliminates the need for a conventional base plate, allows for confirmation of the flatness of the top surface of the foundation concrete, and enables the construction of a seismic isolation foundation with a flat top surface. Furthermore, if the flatness of the top surface of the foundation concrete is insufficient, repairs can be made as needed to ensure the flatness of the top surface of the foundation concrete.

[0013] In this embodiment, a frame-shaped plate embedded in the top surface of the foundation concrete is provided with anchor bolts directly or indirectly on its underside, and further, it is provided with bolt holes into which the seismic isolation device is bolted, thereby enabling it to perform the same function as a conventional base plate. These bolt holes can be used not only for bolting to the seismic isolation device, but also when temporarily fixing the top plate with bolts. Here, "a frame-shaped plate is provided with anchor bolts directly or indirectly on its underside" means both that the heads of the anchor bolts are directly fixed to the underside of the frame-shaped plate by welding or the like, and that the anchor bolts are indirectly fixed to the underside of the frame-shaped plate by welding or the like to a long nut, and the heads of the anchor bolts are fixed to the long nut.

[0014] Furthermore, the top plate removed after the concrete has cured can be reused in the construction of another seismic isolation foundation.

[0015] Herein, in this specification, "concrete" includes not only literal concrete but also mortar (including high-flow mortar), and therefore encompasses all cement-based materials.

[0016] Furthermore, in another embodiment of the seismic isolation foundation construction method according to the present invention, The preparation step is characterized in that a long nut is fixed to the lower surface of the frame-shaped plate at a position corresponding to the bolt hole, and the upper part of the anchor bolt is screwed into the lower part of the long nut.

[0017] According to this embodiment, a long nut is fixed to the lower surface of the frame-shaped plate at a position corresponding to the bolt hole, and the upper part of the anchor bolt is screwed into the lower part of the long nut. Thus, in addition to fixing the anchor bolt, the long nut can be used for bolting to the seismic isolation device together with the bolt hole in the frame-shaped plate.

[0018] Furthermore, other embodiments of the seismic isolation foundation construction method according to the present invention are: A method for constructing a seismic isolation foundation, on which seismic isolation devices are installed, A preparatory step involves setting up a frame-shaped formwork, installing a top plate equipped with filling holes, air vents, and bolt holes, where long nuts are placed on the underside of the top plate at positions corresponding to the bolt holes, the upper part of an anchor bolt is screwed into the lower part of the long nut, and a bolt is inserted through the bolt hole and the long nut to temporarily fix the long nut in place, and then installing the top plate on the upper inside of the formwork. A concrete filling step is to fill the inside of the formwork with concrete through the filling holes and fill the concrete up to the lower surface of the top plate, The invention is characterized by having a curing and demolding step, in which the seismic isolation foundation is constructed in which the long nuts to which the seismic isolation device is bolted and the anchor bolts to which the anchor bolts are embedded in the foundation concrete, by curing the aforementioned concrete to form the foundation concrete, removing the aforementioned bolts, removing the aforementioned top plate, and demolding the formwork.

[0019] According to this aspect, a long nut is disposed on the lower surface at a position corresponding to the bolt hole in the top-end plate provided with a filling hole, an air vent hole, and a bolt hole. The upper part of an anchor bolt is screwed below the long nut. With a bolt inserted through the bolt hole and the long nut to temporarily fix the long nut to the top-end plate, the top-end plate is installed inside above the formwork, the formwork is filled with concrete, and after curing to form the foundation concrete, the top-end plate is removed to construct the seismic isolation foundation. Thus, the conventional base plate can be eliminated and the flatness of the top end of the seismic isolation foundation can be confirmed, and a seismic isolation foundation with a flat top end can be constructed. Also in this aspect, when the flatness of the top end of the foundation concrete is insufficient, the flatness of the top end of the foundation concrete can be ensured by performing repairs as necessary.

[0020] In this aspect, the long nut embedded in the top end of the foundation concrete has an anchor bolt below it, and the upper part of the long nut becomes a bolt hole to which the seismic isolation device is bolted, so that it can perform the same function as the conventional base plate. The long nut is applied to the bolt connection with the seismic isolation device and is also applied when temporarily fixing the top-end plate by bolt connection.

[0021] Also, in another aspect of the method for constructing a seismic isolation foundation according to the present invention, In the curing and demolding step, a first plug and a second plug provided with air vent holes are respectively attached to the filling hole and the air vent hole, and the lower surfaces of the lower surface of the top-end plate, the first plug, and the second plug are flush with each other.

[0022] According to this aspect, during curing after filling with concrete, a first plug and a second plug provided with air vent holes are respectively attached to the filling hole and the air vent hole, and by making the lower surfaces of the lower surface of the top-end plate, the first plug, and the second plug flush with each other, it is possible to construct foundation concrete with the flatness of the top end ensured over the entire area of the lower surface of the top-end plate while suppressing the filled concrete from overflowing from the filling hole and the air vent hole.

[0023] Since both the first plug and the second plug have air vent holes, when they are inserted into the filling hole or the air vent hole, it is possible to prevent air from being pushed below the top plate, and the plugs can be inserted while venting air through the air vent holes.

[0024] When concrete enters the air vent hole and hardens, when the top plate is removed after curing, a thin concrete piece in the shape of the air vent hole is formed protruding from the top end of the foundation concrete. However, since it is a thin concrete piece, it can be easily broken off from its root and removed.

[0025] Also, in another aspect of the method for constructing a seismic isolation foundation according to the present invention, In the curing and demolding step, after removing the top plate, when there is a recess larger than the set size at the top end of the foundation concrete and repair is necessary, the recess is closed with a repair material and the surface is leveled.

[0026] According to this aspect, since the top plate can be removed, when there is a recess larger than the set size at the top end of the foundation concrete and repair is necessary when the top plate is removed, by closing the recess with a repair material and leveling the surface, the flatness of the top end of the foundation concrete can be ensured. Here, examples of the repair material include filling mortar, filling concrete, filling resin, etc. Also, there are various repair methods, such as a method of putting the repair material into the recess and leveling it with a trowel, a method of injecting the repair material into the recess, etc.

[0027] Also, in another aspect of the method for constructing a seismic isolation foundation according to the present invention, In the preparation step, a height adjustment jig is erected from the construction surface of the seismic isolation foundation, and the frame-shaped plate or the top plate is supported by the height-adjusted height adjustment jig, and the frame-shaped plate or the top plate is installed inside above the formwork.

[0028] According to this embodiment, by supporting the frame-shaped plate or top plate with a height adjustment jig erected from the construction surface of the seismic isolation foundation, the frame-shaped plate or top plate can be installed at the correct height position (the top surface position of the foundation concrete being constructed) on the inside of the upper part of the formwork. Here, the height adjustment jig will be embedded (permanently embedded) inside the foundation concrete.

[0029] Furthermore, in another embodiment of the seismic isolation foundation construction method according to the present invention, The concrete filling process is characterized by attaching a hopper to the filling hole and filling the area below the top plate through the hopper.

[0030] According to this embodiment, by attaching a hopper to the filling hole and filling the area below the top plate through the hopper, the concrete filling performance is improved, and it is possible to prevent concrete from splashing onto the upper surface of the top plate during filling. [Effects of the Invention]

[0031] As can be understood from the above explanation, the seismic isolation foundation construction method of the present invention eliminates the base plate embedded in the top surface of the foundation concrete, thereby preventing the construction of a seismic isolation foundation in which an air pocket exists between the lower surface of the base plate and the top surface of the foundation concrete that does not meet the standard value. Thus, a seismic isolation foundation with guaranteed top surface flatness can be constructed while eliminating the need for a base plate. [Brief explanation of the drawing]

[0032] [Figure 1] This diagram shows an example of a construction method for a seismic isolation foundation according to the first embodiment, and illustrates the location where anchor bolts are attached to a frame-shaped plate. [Figure 2] This diagram shows an example of a construction method for a seismic isolation foundation according to the first embodiment, and illustrates a point where a frame-shaped plate is supported by a height adjustment jig. [Figure 3] This is a view from the direction of arrow III in Figure 1. [Figure 4] Following Figure 1, this is a process diagram illustrating an example of a construction method for a seismic isolation foundation according to the first embodiment. [Figure 5] This is a view in the direction of arrow V in Figure 4. [Figure 6] Following Figure 4, this is a process diagram of an example of a construction method for a seismic isolation foundation according to the first embodiment. [Figure 7] Following Figure 6, this is a process diagram of an example of a construction method for a seismic isolation foundation according to the first embodiment. [Figure 8] Following Figure 7 is a process diagram illustrating an example of the construction method for a seismic isolation foundation according to the first embodiment. [Figure 9] Following Figure 8, this figure shows a process diagram of an example of a construction method for a seismic isolation foundation according to the first embodiment, and is a diagram showing an example of a constructed seismic isolation foundation. [Figure 10] This is a longitudinal cross-sectional view showing the seismic isolation device attached to the constructed seismic isolation foundation. [Figure 11] This is a process diagram of an example of a construction method for a seismic isolation foundation according to the second embodiment. [Figure 12] This diagram shows a process diagram of an example of a construction method for a seismic isolation foundation according to the second embodiment, and also shows another example of a constructed seismic isolation foundation. [Modes for carrying out the invention]

[0033] The construction methods for the seismic isolation foundations according to each embodiment will be described below with reference to the attached drawings. In this specification and the drawings, substantially identical components may be denoted by the same reference numerals to avoid redundant explanations.

[0034] [Construction method for seismic isolation foundation according to the first embodiment] First, an example of a construction method for a seismic isolation foundation according to the first embodiment will be described with reference to Figures 1 to 9. Here, Figures 1, 2, 4, and 6 to 9 are, in order, process diagrams of an example of a construction method for a seismic isolation foundation according to the first embodiment, and Figure 9 further shows an example of a constructed seismic isolation foundation. Also, Figure 3 is a view in direction III of Figure 1, and Figure 5 is a view in direction V of Figure 4.

[0035] The following describes a method for constructing a seismic isolation foundation 100 having a rectangular (square in the illustrated example) rectangular foundation concrete 80 in plan view. However, the outer shape of the foundation concrete to be constructed may be a polygonal column shape other than a square in plan view, or it may be a cylindrical or elliptical column shape, etc.

[0036] As shown in Figures 1 and 3, a rectangular frame-shaped formwork 10 (side frame) is installed at a predetermined position on the construction surface F at the site. Note that the illustration of support members and other components that support the formwork 10 from the outside is omitted.

[0037] When installing the frame-shaped plate 30 inside the upper part of the frame-shaped formwork 10, the frame-shaped plate 30 is provided with multiple bolt holes 32 at intervals, and the upper ends of long nuts 37, each having a bolt hole 38, are welded to the lower surface of the frame-shaped plate 30 at positions corresponding to each bolt hole 32, and the upper part of an anchor bolt 35 is screwed into the bolt hole 38 of each long nut 37.

[0038] As shown in Figure 2, height adjustment jigs 20 are installed at multiple locations on the lower surface of the frame-shaped plate 30 where there are no bolt holes 32, and the frame-shaped plate 30 is placed on multiple height adjustment jigs 20 whose heights have been adjusted. The frame-shaped plate 30 is, for example, a steel plate and has a square shape in plan view that is smaller than the plan view dimensions of the formwork 10.

[0039] The height adjustment jig 20 comprises, for example, an L-shaped plate 21, a lower plate 22 joined to its lower end, and an upper plate 23 joined to its upper end. A height adjustment bolt 25 is screwed into a bolt hole 23a provided in the upper plate 23. By adjusting the height of the height adjustment bolt 25, the frame-shaped plate 30 placed on the upper end of the height adjustment bolt 25 can be set to a desired height level.

[0040] Furthermore, the height adjustment jig 20 is a component that is embedded in the foundation concrete 80 (see Figure 6).

[0041] Next, as shown in Figures 4 and 5, a top plate 40, which is square in plan view and made of, for example, steel, is installed on the upper surface of the frame-shaped plate 30.

[0042] The top plate 40 has a filling hole 44 in its center, multiple bolt holes 42 at positions corresponding to the multiple bolt holes 32 of the frame-shaped plate 30, and further multiple air vents 46.

[0043] The bolts 50 are inserted through the bolt holes 42 of the top plate 40, the bolt holes 32 of the frame plate 30, and the bolt holes 38 of the long nuts 37, which are aligned with each other, thereby temporarily fixing the top plate 40 to the frame plate 30. Here, "temporarily fixed" means that the top plate 40 will eventually be removed from the frame plate 30 (this concludes the preparation process).

[0044] Next, as shown in Figure 6, a hopper 60 is attached to the filling hole 44 of the top plate 40, and concrete C is filled in the direction X1 below the top plate 40 via the hopper 60.

[0045] As shown in Figure 7, concrete C is filled into the formwork 10 up to the lower surface 41 of the top plate 40. During this filling process, air present below the top plate 40 is discharged to the outside through multiple air vents 46 (concrete filling process).

[0046] Once the concrete has filled up to the lower surface 41 of the top plate 40, the hopper 60 is removed from the filling hole 44, the first sealing plug 70A is installed in the filling hole 44, and the second sealing plug 70B is installed in the air vent hole 46.

[0047] The first sealing plug 70A has an air vent hole 72 in its center, and the second sealing plug 70B has an air vent hole 74 in its center. Furthermore, when the first sealing plug 70A is installed in the filling hole 44 and the second sealing plug 70B is installed in the air vent hole 46, the lower surface 41 of the top plate 40, the lower surface 71A of the first sealing plug 70A, and the lower surface 71B of the second sealing plug 70B are flush with each other.

[0048] In this way, the filling holes 44 and the air vent holes 46 are closed by the first and second plugs 70A and 70B, and the lower surfaces 41, 71A, and 71B are flush, so that a foundation concrete 80 with a flat upper surface can be constructed over the entire lower surface of the top plate 40.

[0049] Furthermore, since the first closure plug 70A and the second closure plug 70B are each equipped with air vents 72 and 74, the first closure plug 70A and the second closure plug 70B can be installed in the filling hole 44 and the air vent hole 46 while discharging air to the outside in the X2 and X3 directions, and air is prevented from being pushed downwards during installation.

[0050] After the filled concrete has been cured to achieve the required strength, the formwork 10 is removed as shown in Figure 8, and the top plate 40 is removed from the frame plate 30, thereby constructing the foundation concrete 80.

[0051] Inside the foundation concrete 80, a height adjustment jig 20 is embedded, a frame-shaped plate 30 is embedded in the top surface 82, and multiple anchor bolts 35 extending downward from a long nut 37 on the underside of the frame-shaped plate 30 are embedded.

[0052] As shown in Figure 8, thin concrete pieces C1 and C2 in the shape of air vents 72 and 74 may be formed on the top surface 82 of the foundation concrete 80. In such cases, the thin concrete pieces C1 and C2 are broken off and removed from their bases.

[0053] If the entire top surface 82 of the foundation concrete 80 is flat, then the construction of the foundation concrete 80 will be completed, and a seismic isolation foundation will be constructed in which the foundation concrete 80 and the frame-shaped plate 30 and anchor bolts 35 are embedded inside will be installed.

[0054] On the other hand, as shown in the illustrated example, if there are multiple recesses R (or protrusions in the illustrated example) on the top surface 82 of the foundation concrete 80 when the top plate 40 is removed, criteria for determining whether repair is necessary regarding the depth of the recesses and their width in plan view are established in advance. If the recesses R are larger than the size set, the flatness of the entire top surface 82 is ensured by repairing the recesses R (or protrusions).

[0055] Specifically, as shown in Figure 9, the seismic isolation foundation 100 is constructed by filling the recess R with mortar 85 using plastering or the like to eliminate the recess R, and then finishing the entire top surface 82 to be flat. There are various repair methods, such as injecting repair material into the recess R (the above is the curing and demolding process).

[0056] According to the illustrated construction method, a frame-shaped plate 30, to which anchor bolts 35 are attached via long nuts 37 on its lower surface, is installed inside the upper part of a frame-shaped formwork 10. A top plate 40, equipped with filling holes 44 and air vents 46, is placed on top of the frame-shaped plate 30. Concrete C is then filled into the inside of the formwork 10, and after curing, the foundation concrete 80 is formed. After the top plate 40 is removed, the seismic isolation foundation 100 is constructed. This eliminates the need for a conventional base plate, allows for confirmation of the flatness of the top surface 82 of the foundation concrete 80, and enables the construction of a seismic isolation foundation 100 with a flat top surface 82. Furthermore, if the flatness of the top surface 82 of the foundation concrete 80 is insufficient, repairs can be made as needed to ensure the flatness of the top surface 82 of the foundation concrete 80.

[0057] As shown in Figure 10, the seismic isolation device 200 is installed on the constructed seismic isolation foundation 100. Here, the seismic isolation device 200 in the illustrated example is a device in which laminated rubber is sandwiched between an upper plate and a lower plate 210, but various structures and mechanisms of seismic isolation devices such as sliding seismic isolation devices may be applied.

[0058] In the lower plate 210 of the seismic isolation device 200, bolt holes 212 are provided at positions corresponding to the bolt holes 32 of the frame-shaped plate 30. By inserting bolts 250 through the mutually aligned bolt holes 212 and 32 and the bolt hole 38 of the long nut 37, the seismic isolation foundation 100 and the seismic isolation device 200 are connected.

[0059] [Construction method for seismic isolation foundation according to the second embodiment] Next, an example of a construction method for a seismic isolation foundation according to the second embodiment will be described with reference to Figures 11 and 12. Here, Figures 11 and 12 are process diagrams of an example of a construction method for a seismic isolation foundation according to the second embodiment, and Figure 11 further shows another example of a constructed seismic isolation foundation.

[0060] Here, the construction method according to the second embodiment differs from the construction method according to the first embodiment in that it applies long nuts 90 instead of frame-shaped plates 30, but the basic configuration of the other construction methods is substantially the same as that of the construction method according to the first embodiment, so the illustration of a process diagram showing the same content is omitted.

[0061] As shown in Figure 11, in the preparation step, a frame-shaped formwork 10 is installed, and a long nut 90 is placed on the lower surface of the top plate 40, which has filling holes 44, air vent holes 46 and bolt holes 42, at the position corresponding to the bolt holes 42, the upper part of the anchor bolt 35 is screwed into the lower part of the long nut 90, and the bolt 50 is inserted through the bolt hole 42 and the long nut to temporarily fix the long nut 90 to the top plate 40. Height adjustment jigs 20, as explained with reference to Figure 2, are installed at multiple locations on the lower surface of the top plate 40 where multiple anchor bolts 35 are not attached, and the top plate 40 is placed on top of multiple height adjustment jigs 20 so that the top plate 40 is installed on the upper inside of the formwork 10.

[0062] Next, the hopper 60 is placed in the filling hole 44 and concrete C is filled in, the first sealing plug 70A and the second sealing plug 20B are attached to the filling hole 44 and the air vent hole 46 and cured, and the formwork 10 is removed and the top plate 40 is removed, which is the same as the construction method of the first embodiment.

[0063] By removing the formwork 10 and the top plate 40, a seismic isolation foundation 100A is constructed, as shown in Figure 12, in which multiple long nuts 90 and anchor bolts 35 are embedded inside the foundation concrete 80.

[0064] In this construction method as well, when the top plate 40 is removed, if there are multiple recesses R on the top surface 82 of the foundation concrete 80, and these recesses R are larger than the set size, the flatness of the entire top surface 82 is ensured by repairing the recesses R.

[0065] Furthermore, other embodiments may be used in which other components are combined with the configurations listed in the above embodiments, and the present invention is not limited in any way to the configurations shown herein. In this regard, modifications can be made without departing from the spirit of the present invention, and can be appropriately determined according to the application form. [Explanation of symbols]

[0066] 10: Formwork 20: Height adjustment jig 21: L-shaped plate 22: Lower plate 23: Top plate 23a: Bolt hole 25: Height adjustment bolt 30: Frame-shaped plate 32: Bolt holes 35: Anchor bolts 37: Long nut 38: Bolt holes 40: Top plate 41: Bottom surface 42: Bolt holes 44: Filling hole 46: Air vent 50: Bolt 60: Hopper 70A: First blockage valve 71A: Bottom surface 70B:Second obstruction plug 71B:Bottom surface 72,74: Air vent holes 80: Foundation concrete 82: Top 85: Filling mortar 90: Long nut 92: Bolt holes 100, 100A: Seismic isolation foundation 200: Seismic isolation device 210: Lower plate 212: Bolt hole 250: Bolt F: Construction side C: Concrete R: recessed C1:C2:Concrete fragments

Claims

1. A method for constructing a seismic isolation foundation, on which seismic isolation devices are installed, A preparatory step involves setting up a frame-shaped formwork, installing a frame-shaped plate inside the upper part of the formwork, where the frame-shaped plate is equipped with bolt holes for bolting the seismic isolation device, and anchor bolts are directly or indirectly attached to its lower surface, and then installing a top plate equipped with filling holes and air vents on top of the frame-shaped plate. A concrete filling step is to fill the inside of the formwork with concrete through the filling holes and fill the concrete up to the lower surface of the top plate, A method for constructing a seismic isolation foundation, characterized by comprising a curing and demolding step, in which the concrete is cured to form a foundation concrete, the top plate is removed, the formwork is demolded, and the frame-shaped plate equipped with the anchor bolts is embedded in the foundation concrete, thereby constructing a seismic isolation foundation.

2. The method for constructing a seismic isolation foundation according to claim 1, characterized in that, in the preparation step, a long nut is fixed to the lower surface of the frame-shaped plate at a position corresponding to the bolt hole, and the upper part of the anchor bolt is screwed into the lower part of the long nut.

3. A method for constructing a seismic isolation foundation, on which seismic isolation devices are installed, A preparatory step involves setting up a frame-shaped formwork, installing a top plate equipped with filling holes, air vents, and bolt holes, where long nuts are placed on the underside of the top plate at positions corresponding to the bolt holes, the upper part of an anchor bolt is screwed into the lower part of the long nut, and a bolt is inserted through the bolt hole and the long nut to temporarily fix the long nut in place, and then installing the top plate on the upper inside of the formwork. A concrete filling step is to fill the inside of the formwork with concrete through the filling holes and fill the concrete up to the lower surface of the top plate, A method for constructing a seismic isolation foundation, comprising a curing and demolding step, in which the concrete is cured to form the foundation concrete, the bolts are removed, the top plate is removed, and the formwork is demolded, thereby constructing a seismic isolation foundation in which the long nuts to which the seismic isolation device is bolted and the anchor bolts are embedded in the foundation concrete.

4. The method for constructing a seismic isolation foundation according to claim 1 or 3, characterized in that, in the curing and demolding step, a first and second closure plugs, each equipped with an air vent hole, are installed in the filling hole and the air vent hole, respectively, and the lower surface of the top plate and the lower surfaces of the first and second closure plugs are made flush.

5. The method for constructing a seismic isolation foundation according to claim 4, characterized in that, in the curing and demolding step, after removing the top plate, if there is a recess on the top surface of the foundation concrete that is larger than the set size and requires repair, the recess is filled with repair material and the surface is leveled.

6. The method for constructing a seismic isolation foundation according to claim 1 or 3, characterized in that in the preparation step, a height adjustment jig is erected from the construction surface of the seismic isolation foundation, and the frame-shaped plate or the top plate is supported by the height-adjusted height adjustment jig, thereby installing the frame-shaped plate or the top plate on the upper inside of the formwork.

7. The method for constructing a seismic isolation foundation according to claim 6, characterized in that, in the concrete filling step, a hopper is attached to the filling hole and concrete is filled below the top plate through the hopper.

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