Base isolation packing under wooden sill and base isolation mechanism for building provided with said base isolation packing

Abstract

Provided are: base isolation packing under a wooden sill, the base isolation packing having the function of isolating seismic force by using a simple installation method not involving complex structural calculations; and a base isolation mechanism for a building provided with the said base isolation packing.　This base isolation mechanism for a building comprises: a foundation 1 in which an anchor bolt 40 is embedded; a sill 2 in which is formed a through hole 50 into which the anchor bolt 40 is inserted; and a base isolation packing 10 under a wooden sill, the base isolation packing 10 being interposed between the foundation 1 and the sill 2. The base isolation packing 10 under the wooden sill is configured such that during an earthquake, a contact surface thereof that is in contact with the sill 2 slides, and a contact surface of the base isolation packing that is in contact with the foundation 1 does not slide.

Description

Seismic isolation packing under wooden foundation and seismic isolation mechanism for buildings equipped with it

[0001] The present invention relates to a seismic isolation packing for under wooden foundations and a seismic isolation mechanism for buildings equipped with the same.

[0002] A known seismic isolation mechanism using anchor bolts and friction seismic isolation devices includes an anchor bolt embedded in the foundation of a building to secure the foundation, a through-hole through which the anchor bolt is inserted and which passes vertically through the foundation, a nut screwed onto the upper end of the anchor bolt, and a friction seismic isolation device interposed between the foundation and the base (see Patent Document 1). The friction seismic isolation device includes a first sliding plate located at an upper level and in close contact with the base, and a second sliding plate located at a lower level and in close contact with the base, and the surfaces where the first and second sliding plates overlap are smooth. In this seismic isolation mechanism, the smooth portion of the friction seismic isolation device functions as a sliding surface that slides during an earthquake, and multiple small seismic isolation devices that use the bending stress of the anchor bolt as a spring are activated, providing a significant seismic isolation effect.

[0003] Patent No. 7018550

[0004] However, since the load of a building flows mainly through the columns, then through the foundation, and then through the friction seismic isolation device to the foundation and ground, it is reasonable to calculate the number of friction seismic isolation devices to be installed near the columns depending on the magnitude of the load transmitted to each column, which requires engineers with extensive structural knowledge. As a result, despite the prediction of a large earthquake, the current situation is such that widespread use of such devices is uncertain. Therefore, the inventor of the present application has been actively studying seismic isolation mechanisms with a structure different from that of Patent Document 1.

[0005] The present invention aims to provide a seismic isolation packing for under wooden foundations that has the function of isolating earthquake forces with a simple installation method that does not require complex structural calculations, and a seismic isolation mechanism for buildings that is equipped with the same.

[0006] In order to achieve the above-mentioned objective, the present invention provides a seismic isolation packing that is inserted between the foundation and base of a building, and that is a wooden base-under seismic isolation packing that, during an earthquake, has a sliding surface that contacts the base and a non-slip surface that contacts the base.

[0007] In the above-mentioned seismic isolation packing for under wooden foundations, it is preferable that the upper surface that comes into contact with the foundation is a smooth surface, and the lower surface that comes into contact with the foundation has a convex portion or is a rough surface.

[0008] The above-mentioned wooden foundation seismic isolation gasket preferably has a flat plate portion extending horizontally and a plurality of pillar portions extending downward from the flat plate portion.

[0009] In addition, in the above-mentioned seismic isolation packing for under wooden foundations, it is preferable that each of the pillars has a ventilation section that allows air to circulate horizontally.

[0010] Furthermore, the seismic isolation packing for under the wooden foundation may be made of plastic.

[0011] Furthermore, the seismic isolation packing for under the wooden foundation may be made of engineering plastic.

[0012] Furthermore, the seismic isolation packing for under the wooden foundation may be made of metal.

[0013] Furthermore, it is preferable that the above-mentioned seismic isolation packing for under wooden foundations has a notch that is cut out from the outer edge toward the inside in a plan view to avoid interference with the anchor bolt.

[0014] In order to achieve the above-mentioned object, the present invention provides a seismic isolation mechanism for a building, which comprises a foundation into which an anchor bolt is buried, a base sill in which a through hole into which the anchor bolt is inserted is formed, and the above-mentioned wooden base under-base seismic isolation gasket interposed between the foundation and the base sill.

[0015] In the seismic isolation mechanism for a building, it is preferable that the difference between the diameter of the through hole and the diameter of the anchor bolt is 10 mm or more.

[0016] According to the present invention, it is possible to provide a function of isolating earthquake forces with a simple installation method that does not involve complex structural calculations.

[0017] FIG. 1 is a schematic side explanatory view of a building illustrating a first embodiment of the present invention. FIG. 2 is a schematic partial plan explanatory view of a building illustrating the arrangement of a wooden base seismic isolation packing. FIG. 3 is an enlarged side explanatory view of an anchor bolt and a through hole. FIG. 4 is an underside view of a wooden base seismic isolation packing. FIG. 5 is a side sectional view of a wooden base seismic isolation packing. FIG. 6 is a schematic side explanatory view of a building illustrating a modified example of the first embodiment. FIG. 7 is an underside view of a wooden base seismic isolation packing illustrating a modified example of the first embodiment. FIG. 8 is a side sectional view of a wooden base seismic isolation packing illustrating a modified example of the first embodiment. FIG. 9 is a side sectional view of a wooden base seismic isolation packing illustrating a modified example of the first embodiment. FIG. 10 is an underside view of a wooden base seismic isolation packing illustrating a modified example of the first embodiment. FIG. 11 is an enlarged side explanatory view of an anchor bolt and a through hole illustrating a modified example of the first embodiment. FIG. 12 is an enlarged side explanatory view of an anchor bolt and a through hole illustrating a modified example of the first embodiment. FIG. 13 is an enlarged side explanatory view of an anchor bolt and a through hole illustrating a modified example of the first embodiment. 1 is a schematic side view of a building according to a second embodiment of the present invention; FIG. 2 is a schematic partial plan view of a building showing the arrangement of wooden-foundation under-seismic isolation packings; FIG. 3 is a side view of a wooden-foundation under-seismic isolation packing; FIG. 4 is a schematic cross-sectional view of a building showing the thermal insulation state when foundation insulation is performed; FIG. 5 is a top view of a wooden-foundation under-seismic isolation packing showing a modification of the second embodiment; FIG. 6 is a bottom view of a wooden-foundation under-seismic isolation packing showing a modification of the second embodiment; FIG. 7 is a side cross-sectional view of a wooden-foundation under-seismic isolation packing showing a modification of the second embodiment; FIG. 8 is a schematic side view of a building according to a third embodiment of the present invention; FIG. 9 is a schematic plan view of a building showing the arrangement of wooden-foundation under-seismic isolation packings; FIG. 10 is a schematic cross-sectional view of a first wooden-foundation under-seismic isolation packing; Fig. 1 is a bottom view of a second wooden base under seismic isolation gasket. Fig. 2 is a side cross-sectional view of a second wooden base under seismic isolation gasket. Fig. 3 is a bottom view of a third wooden base under seismic isolation gasket. Fig. 4 is a side cross-sectional view of a third wooden base under seismic isolation gasket. Fig. 5 is a schematic side explanatory view of a building showing an insulated state.1 is a bottom view of a first wooden base seismic isolation gasket showing a modified example of the third embodiment, (a) showing the entire structure, and (b) showing only the cylindrical portion. FIG. 2 is a side cross-sectional view of a first wooden base seismic isolation gasket showing a modified example of the third embodiment, (a) showing the entire structure, and (b) showing only the cylindrical portion. FIG. 3 is a schematic side explanatory view of a building showing a fourth embodiment. FIG. 4 is a top view of a first wooden base seismic isolation gasket. FIG. 5 is a side view of a first wooden base seismic isolation gasket, (a) showing the entire structure, and (b) showing only the end portion on the inclined surface side. FIG. 6 is a top view of a second wooden base seismic isolation gasket. FIG. 7 is a side view of a second wooden base seismic isolation gasket. FIG. 8 is a top view of a third wooden base seismic isolation gasket. FIG. 9 is a side view of a third wooden base seismic isolation gasket.

[0018] Figures 1 to 5 show a first embodiment of the present invention, in which Figure 1 is a schematic side view of a building, Figure 2 is a schematic partial plan view of the building showing the arrangement of seismic isolation packing under a wooden foundation, Figure 3 is an enlarged side view of anchor bolts and through holes, Figure 4 is a bottom view of the seismic isolation packing under a wooden foundation, and Figure 5 is a side cross-sectional view of the seismic isolation packing under a wooden foundation. Note that Figures 1 to 3 are explanatory views, and hatching and the like are omitted.

[0019] As shown in FIG. 1 , the wooden under-foundation seismic isolation gaskets 10 are interposed between the foundation 1 and the foundation 2 of a building in a distributed manner. The wooden under-foundation seismic isolation gaskets 10 are arranged in portions of the foundation 1 where a relatively large load is applied. Specifically, as shown in FIG. 2 , each wooden under-foundation seismic isolation gasket 10 is arranged so as to overlap all of the columns 3 on the foundation 1 in a plan view, and also so as to overlap the main underpinnings in a plan view. A plurality of anchor bolts 40 for securing the foundation 2 are embedded in the foundation 1 at a predetermined distance from the center of the columns 3. In this embodiment, the anchor bolts 40 are embedded 200 mm from the center of the columns 3. The anchor bolts 40 extend upward from the foundation 1 and are inserted into through-holes 50 that penetrate the foundation 2 from top to bottom, and are threadedly engaged with nuts 60 at their upper ends. When hold-down hardware 4 is provided on the columns 3 of a building as shown in FIGS. 1 and 2 , anchor bolts 70 separate from the anchor bolts 40 for securing the foundation 2 are connected. In this embodiment, the building is made of wood, with the foundation 1 made of concrete and the base 2 made of wood.

[0020] As shown in Figure 3, the nut 60 has a long nut portion 61 that screws onto the anchor bolt 40 and a round seat 62 formed on the upper end of the long nut portion 61. The nut 60 is a so-called countersunk nut, and the underside of the round seat 62 has multiple triangular ridges 63 that radiate outward in the radial direction. Each triangular ridge 63 has a triangular cross section with an acute apex angle, and is formed so that the height of the apex increases as it moves radially outward. In this embodiment, after tightening, the upper end of the nut 60 is flush with the upper surface of the base 2. The top of the anchor bolt 40 is restrained by the nut 60, which has the long nut portion 61 and the round seat 62.

[0021] In this embodiment, the height and width dimensions of the base 2 are set to 105 mm, the diameter of the anchor bolt 40 to 12 mm, the diameter of the through hole 50 to 24 mm, and the diameter of the round seat 62 of the nut 60 to 45 mm. The dimensions of the base 2 are arbitrary; for example, the height and width dimensions may be 89 mm, 120 mm, etc. The diameters of the anchor bolt 40 and the through hole 50 may also be changed arbitrarily; for example, the diameter of the anchor bolt 40 may be 16 mm and the diameter of the through hole 50 to 28 mm. Here, the term "diameter of the anchor bolt" in the specification refers to the diameter of the threaded portion at the upper end, not the diameter of the unthreaded portion at the lower end of the anchor bolt. In other words, a "diameter of the anchor bolt" of 12 mm means that the diameter of the threaded portion at the upper end is 12 mm, and the diameter of the unthreaded portion at the lower end may be, for example, 12 mm or 10.6 mm. Considering the seismic isolation effect of the building during an earthquake, it is preferable that the diameter of the through hole 50 be 10 mm or more larger than the diameter of the anchor bolt 40. Furthermore, considering damage to various parts of the building and various pieces of equipment during an earthquake, it is preferable that the difference between the diameter of the through hole 50 and the diameter of the anchor bolt 40 be 30 mm or less.

[0022] As shown in FIG. 2 , the wooden foundation seismic isolation gasket 10 is rectangular in plan view and is positioned so as not to interfere with the anchor bolts 40, 70. The wooden foundation seismic isolation gasket 10 may be made of any material, but in this embodiment, it is made of engineering plastic. Examples of engineering plastics include polyamide, polyacetal, polycarbonate, modified polyphenylene ether, polybutylene terephthalate, polyphenylene sulfide, polysulfone, polyethersulfone, polyarylate, polyamideimide, polyetheretherketone, and liquid crystal polymer. The wooden foundation seismic isolation gasket 10 can also be made of fiber-reinforced plastic, which is made of a plastic base material reinforced with glass fiber, carbon fiber, or the like. In this specification, "plastic" also includes fiber-reinforced plastic.

[0023] As shown in Figures 4 and 5, the wooden foundation seismic isolation packing 10 has a flat plate portion 11 and multiple cylindrical portions 12 protruding downward from the flat plate portion 11. The flat plate portion 11 is formed in a rectangular shape in a plan view, and its upper surface forms a smooth surface 14 that contacts the foundation 2. In this embodiment, the longitudinal dimension of the flat plate portion 11 is set to be equal to the distance from the center of the column 3 to the anchor bolt 40, and the wooden foundation seismic isolation packing 10 is positioned so that it overlaps the column 3 in a plan view, thereby preventing interference with the anchor bolt 40. In other words, by setting the longitudinal dimension of the flat plate portion 11 to be greater than the length of one side of the column 3 and equal to or less than the distance from the center of the column 3 to the anchor bolt 40, the wooden foundation seismic isolation packing 10 positioned directly below the column 3 does not interfere with the anchor bolt 40. Specifically, the planar dimensions of the wooden foundation seismic isolation packing 10 in this embodiment are 100 mm in short sides and 200 mm in long sides. The size of the flat plate portion 11 is determined by the strength of the material of the wooden base seismic isolation packing 10 against the building load and the strength of the wood of the foundation 2. When the wooden base seismic isolation packing 10 is made of a relatively strong engineering plastic, as in this embodiment, it is preferable that the size be approximately 100 x 200 mm.

[0024] The cylindrical portions 12 serving as pillars are aligned vertically and horizontally in a plan view, and multiple convex portions 19 are formed on the underside at equal intervals in the circumferential direction. The cylindrical portions 12 may be arranged randomly, rather than being aligned vertically and horizontally, and the arrangement of the cylindrical portions 12 can be arbitrarily changed. Each cylindrical portion 12 functions as a height adjustment portion, and the height of the wooden foundation seismic isolation packing 10 can be arbitrarily changed by adjusting its vertical dimension. In this embodiment, the height of each cylindrical portion 12 is 13 mm. Furthermore, in this embodiment, each convex portion 19 has a truncated cone shape. The shape of each convex portion 19 is arbitrary, and can be, for example, a cylindrical, prismatic, or pyramidal shape. The dimensions of the convex portions 19 are arbitrary, but for example, the height from the bottom surface can be 0.2 mm to 0.3 mm, and the diameter of the base end can be approximately 1 mm. It goes without saying that the size and shape of the cylindrical portion 12 can be changed as appropriate as long as the required strength is ensured and air can pass through.

[0025] As shown in Fig. 5, corners 16 formed by the upper surface and side surface of the flat plate portion 11 are chamfered. In this embodiment, the corners 16 are angular, but they may also be rounded. Also, as shown in Fig. 4, a plurality of ribs 17 are formed on the lower surface of the flat plate portion 11. In this embodiment, the flat plate portion 11 is formed with ribs 17 surrounding each cylindrical portion 12 and ribs 17 connecting the cylindrical portions 12 arranged on the outer edge side. Note that each rib 17 can be omitted as appropriate.

[0026] The following describes the operation of a seismic isolation mechanism for a building equipped with the anchor bolts and wooden base isolation packings configured as described above during an earthquake. When a relative horizontal load is applied to the foundation 1 and the sill 2 during an earthquake, horizontal slippage occurs between the smooth surface 14 of each wooden base isolation packing 10 and the underside of the sill 2, dissipating seismic energy. The upper surface of the wooden base isolation packing 10 slides against the underside of the sill 2, functioning as an isolator. In this embodiment, the corners 16 of each wooden base isolation packing 10 are chamfered, preventing the corners 16 from digging into the sill 2 and facilitating slippage between each wooden base isolation packing 10 and the sill 2. Meanwhile, the convex portions 19 of each cylindrical portion 12 function as anti-slip surfaces, preventing slippage between the lower end of each wooden base isolation packing 10 and the upper surface of the foundation 1. The foundation 1 and each wooden base isolation packing 10 are bonded together with an adhesive as needed. Furthermore, when a relative horizontal load is applied to the foundation 1 and the base 2 during an earthquake, the anchor bolts 40, 70 are bent, generating bending stress inside the anchor bolts 40, 70. Seismic energy is also dissipated by the bending stress of the anchor bolts 40, 70. In this way, the anchor bolts 40, 70 and each wooden base seismic isolation gasket 10 work together to dissipate seismic energy. As such, the seismic isolation mechanism equipped with the newly constructed wooden base seismic isolation gasket 10 of this embodiment is a seismic isolation mechanism that uses the sliding friction between the upper surface of the wooden base seismic isolation gasket 10 and the lower surface of the base 2, and the bending stress of the anchor bolts 40, 70 as springs. Therefore, a relatively large contact surface can be provided to provide ample strength, and the function of isolating seismic force can be imparted with a simple installation method that does not require complex structural calculations.

[0027] In this embodiment, the diameter of the through hole 50 is 10 mm or more larger than the diameter of the anchor bolts 40, 70, so that a relatively large bending stress can be generated in the anchor bolts 40, 70 throughout the entire length of the through hole 50. Furthermore, in this embodiment, the difference between the diameter of the through hole 50 and the diameter of the anchor bolts 40, 70 is 30 mm or less, so that the amount of relative movement between the foundation 1 and the base 2 is kept to 30 mm or less, and a seismic isolation effect can be obtained while reducing the possibility of causing major damage to various parts and equipment of the building during an earthquake.

[0028] Furthermore, according to the wooden foundation seismic isolation packing 10 of this embodiment, the lower side is formed as a cylindrical portion 12, thereby ensuring a wide air flow path between the foundation 1 and the sill 2. In this way, by reducing the air resistance between the foundation 1 and the sill 2 and increasing the ventilation rate, it is possible to suppress termite infestation and decay of the foundation 2. Furthermore, while a height dimension of 15 mm or less is considered preferable to prevent rodent intrusion, by making the vertical dimension of each cylindrical portion 12 13 mm, rodent intrusion can be reliably prevented. In this embodiment, by making the vertical dimension of the cylindrical portion 12 13 mm, even if unevenness occurs in at least one of the foundation 1 and the sill 2, the distance between the foundation 1 and the flat plate portion 81 can be reliably kept 15 mm or less. Furthermore, by making the distance between each cylindrical portion 12, for example, 15 mm or less, rodent intrusion can also be prevented.

[0029] Figures 6 to 8 show modified examples of the first embodiment, with Figure 6 being a schematic side view of a building, Figure 7 being a bottom view of a wooden base seismic isolation gasket, and Figure 8 being a side cross-sectional view of the wooden base seismic isolation gasket. Note that Figure 6 is an explanatory view, and hatching and the like are omitted. As shown in Figure 6, this wooden base seismic isolation gasket 80 is also inserted between the foundation 1 and base 2 of a building. Note that Figure 6 is an explanatory view, and hatching and the like are omitted.

[0030] As shown in Figures 7 and 8, the wooden foundation seismic isolation packing 80 has a flat plate portion 81 and multiple cylindrical portions 82 protruding downward from the flat plate portion 81. The flat plate portion 81 is formed in a rectangular shape in a plan view, and its upper surface forms a smooth surface 84 that contacts the base 2. The cylindrical portions 82 serving as pillars are aligned vertically and horizontally in a plan view, and their lower ends form rough surfaces 85 that contact the foundation 1. As shown in Figures 7 and 8, each cylindrical portion 82 has a slit 82a extending in the width direction of the flat plate portion 81. Each slit 82a is formed in the center of each cylindrical portion 82 in the longitudinal direction of the flat plate portion 81. Each slit 82a is formed from the tip to the base end of each cylindrical portion 82.

[0031] As shown in FIG. 8 , the lower surface of the flat plate portion 81 is formed so that the portions where the columnar portions 82 are formed are raised. Note that FIG. 7 does not show the inclination of the lower surface of the flat plate portion 81. The lower surface of the flat plate portion 81 has inclined portions 81a that are inclined so as to rise from the longitudinal and widthwise ends of the flat plate portion 81 and from the intermediate portions of each columnar portion 82 toward the base end of each columnar portion 82. In this embodiment, the slits 82a of each columnar portion 82 on the lower surface of the flat plate portion 81 are also inclined so as to rise toward the protruding portions 82b of each columnar portion 82. Specifically, the lower surface of the flat plate portion 81 has inclined portions 81b that are inclined so as to rise from the intermediate portions of the pair of protruding portions 82b of each columnar portion 82 toward each protruding portion 82b. Furthermore, in this embodiment, the portions where gates are to be disposed during molding are formed flat. Specifically, the lower surface of the flat plate portion 81 has a flat portion 81c formed in a predetermined range in the center in the longitudinal direction. In this embodiment, the flat portion 81c is formed between each of the two cylindrical portions 82 located in the center in the longitudinal direction.

[0032] Each cylindrical portion 82 functions as a height adjustment portion, and by changing the vertical dimension, the height of the wooden foundation seismic isolation packing 80 can be changed as desired. The vertical dimension of each cylindrical portion 82 is formed to be larger than that of the flat plate portion 81. In this embodiment, the vertical dimension of the flat plate portion 81 is 4 mm, and the vertical dimension of each cylindrical portion 82 is 9 mm. The vertical dimension of this flat plate portion 81 includes a 1 mm height change amount for each of the inclined portions 81 a, 81 b, and the vertical dimension of the thinnest part of the flat plate portion 81 is 3 mm.

[0033] 8, corners 86 formed by the top and side surfaces of the flat plate portion 81 are chamfered. In this embodiment, the corners 86 are curved at a predetermined curvature, and specifically, the radius of curvature of the corners 86 is 2 mm.

[0034] The seismic isolation mechanism for a building equipped with the anchor bolts and wooden base seismic isolation packing configured as described above can also achieve the same effect during an earthquake as in the first embodiment. Furthermore, with this wooden base seismic isolation packing 80, the slits 82a formed in the cylindrical portion 82 can significantly reduce air flow resistance and dramatically increase ventilation volume.

[0035] 7 and 8 show that the inclined surfaces 81b are formed between the protruding portions 82b of each cylindrical portion 82, but the spaces between the protruding portions 82b may be flat, as shown in Fig. 9. Furthermore, the entire lower surface of the flat plate portion 81 may be flat.

[0036] 7 and 8 show the slits 82a formed in the columnar portion 82, but as shown in Fig. 10, for example, the slits 89a may be formed in the cylindrical portion 89. Furthermore, the height adjustment portion may be shaped like a square pillar or square tube, and the slits may be formed therein.

[0037] Furthermore, in the above embodiment, a so-called joist-less construction method has been shown in which the upper end of the nut 60 is at the same level as the upper surface of the foundation 2 or several mm below the upper surface, but it goes without saying that the present invention can also be applied to a so-called joist floor construction method in which the upper ends of the nuts 160, 260, 360 are higher than the upper surface of the foundation 2, as shown in Figures 11 to 13. In the buildings of Figures 11 to 13, the anchor bolt 140 is installed so that its upper end is higher than the surface of the foundation 2 when it is embedded in the foundation 1.

[0038] The nut 160 shown in FIG. 11 does not have the long nut portion 61 and round seat 62 of the nut 60 of the previous embodiment. Instead, it is used in combination with a washer 162 through which the anchor bolt 140 is inserted and which contacts the surface of the base 2. This nut 160 preferably has a locking function, is placed on the upper surface of the washer 162, and threads onto the upper end of the anchor bolt 140. Furthermore, in the modified example shown in FIG. 11 , the through hole 50 is not formed with the same diameter from top to bottom as in the previous embodiment, but rather uses a two-stage through hole 150. The upper diameter of the through hole 150 is smaller than the lower diameter. For example, the lower diameter can be 24 mm, and the upper diameter can be 16 mm to 18 mm. In the modified example shown in FIG. 11 , the smaller upper diameter allows the anchor bolt 140 to have a spring effect against the bending stress. Furthermore, as shown in FIG. 12 , the nut 160 can also be used in combination with a washer 262 that is embedded in the base 2 using a countersink or similar tool. 12, the through-hole 50 has the same diameter from top to bottom. In the case of the modification of Fig. 12, the embedded washer 262 allows the spring of the bending stress of the anchor bolt 140 to be used.

[0039] Furthermore, as shown in FIG. 13 , a washer 362 having a slip prevention function relative to the base 2 can also be used. This washer 362 also allows the bending stress of the anchor bolt 140 to be applied. As shown in FIG. 14 , this washer 362 has a flat portion 362b in which an insertion hole 362a for the anchor bolt 140 is formed, and a protruding portion 362c formed on the outer edge of the flat portion 362b and protruding downward from the flat portion 362b. The washer 362 has a circular shape in a plan view, and the protruding portion 362c is formed by bending the outer edge of the washer 362 so as to slope downward toward the radially outward direction. The diameter of the radially inner end of the protruding portion 362c of the washer 362 is formed to be larger than the diameter of the through-hole 50. The outer diameter of the washer 362 is arbitrary, but can be, for example, 45 mm.

[0040] A method for fastening the anchor bolt 140 and nut 160 to the base 2 using a washer 362 to prevent slippage will be described below. As shown in FIG. 15 , the base 2 is set on the foundation 1 so that the anchor bolt 140 passes through the through-hole 50, and the washer 362 is inserted into the anchor bolt 140 and brought into contact with the upper surface of the base 2. In this state, the nut 160 that threads onto the anchor bolt 140 is tightened to move the washer 362 downward and drive the protruding portion 362c into the base 2. The metal washer 362 has high strength compared to the wooden base 2, so the protruding portion 362c can be smoothly driven into the base 2. After the flat portion 362b comes into contact with the upper surface of the base 2, the downward movement of the washer 362 stops at a position corresponding to the torque of the tool used, and the anchor bolt 140 and the nut 160 are fastened together. This method of fastening the anchor bolt 140 and the nut 160 can be applied to both new building construction and renovation work. In the case of renovation work, the existing nut 160 in a tightened state is temporarily removed from the anchor bolt 140, and after the specified work related to the renovation, such as repairs, is performed, the anchor bolt 140 and the nut 160 are tightened again. When tightening again, the existing nut 160 may be reused, or a new nut 160 may be used.

[0041] According to the fastening structure of the anchor bolt 140 and the nut 160 using the slippage prevention washer 362, the top of the anchor bolt 140 is restrained by the washer 362 toward the base 2. As a result, even if a horizontal force is applied to the base 2 due to shaking, wind, etc., during an earthquake, typhoon, etc., the base 2 will not shift horizontally relative to the anchor bolt 140, washer 362, etc., and the fastened state of the anchor bolt 140 and the nut 160 can be maintained. Therefore, it can be said that the fastening structure of the anchor bolt 140 and the nut 160 using the slippage prevention washer 362 solves the problem of a fastening structure of the anchor bolt and the nut using a flat washer, in which the base and the washer slip and the base shifts horizontally when a horizontal load is applied to the base due to shaking, wind, etc. Although Figures 13 to 15 show that the protruding portion 362c of the washer 362 slopes downward toward the radially outward direction, the shape of the protruding portion 362c can be changed as desired. Furthermore, although the washer 362 has a circular shape in plan view, the shape of the washer 362 in plan view is not limited to this.

[0042] The following (1) to (3) are examples of means for solving the problem of horizontal displacement of the base when a flat washer is used: (1) A method for fastening an anchor bolt to a nut comprising: a foundation, an anchor bolt extending upward from the foundation, a wooden base placed above the foundation, a through hole formed in the base and through which the anchor bolt is inserted, a washer inserted into the anchor bolt and in contact with the upper surface of the base, and a nut threaded onto the upper end of the anchor bolt, wherein a predetermined clearance is ensured between a wall surface of the through hole and the anchor bolt, the washer having a flat portion in which an insertion hole for the anchor bolt is formed, and a protruding portion formed on the outer edge of the flat portion and protruding downward from the flat portion, the washer inserted into the anchor bolt is placed on the upper surface of the base, and the nut threaded onto the anchor bolt is tightened to move the washer downward, thereby driving at least a portion of the protruding portion into the base. (2) A fastening structure for an anchor bolt and a nut, comprising: a foundation; an anchor bolt extending upward from the foundation; a wooden base arranged above the foundation; a through hole formed in the base and through which the anchor bolt is inserted; a washer inserted into the anchor bolt and in contact with an upper surface of the base; and a nut screwed onto the upper end side of the anchor bolt, wherein a predetermined clearance is ensured between a wall surface of the through hole and the anchor bolt, wherein the washer has a flat portion in which an insertion hole for the anchor bolt is formed, and a protruding portion formed on the outer edge of the flat portion and protruding downward from the flat portion, wherein the protruding portion is recessed into the base, and the flat portion is in contact with the upper surface of the base.(3) A washer for use in a fastening structure of an anchor bolt and a nut, the fastening structure comprising: a foundation; an anchor bolt extending upward from the foundation; a wooden base placed above the foundation; a through hole formed in the base and through which the anchor bolt is inserted; a washer inserted into the anchor bolt and in contact with the upper surface of the base; and a nut screwed onto the upper end of the anchor bolt, the washer having a predetermined clearance between a wall surface of the through hole and the anchor bolt, the washer having: a flat portion in which an insertion hole for the anchor bolt is formed; and a protruding portion formed on the outer edge of the flat portion and protruding downward from the flat portion; and the washer for preventing slippage with the base, the washer being configured so that when the washer is inserted into the anchor bolt and placed on the upper surface of the base and moved downward by tightening the nut screwed onto the anchor bolt, at least a portion of the protruding portion will sink into the base.

[0043] Figures 16 to 20 show a second embodiment of the present invention, with Figure 16 being a schematic side view of a building, Figure 17 being a schematic partial plan view of the building showing the arrangement of seismic isolation packing under the wooden foundation, Figure 18 being a top view of the seismic isolation packing under the wooden foundation, Figure 19 being a side view of the seismic isolation packing under the wooden foundation, and Figure 20 being a schematic cross-sectional view of the building showing the insulated state. Note that Figures 16 and 20 are explanatory views and have omitted hatching and the like.

[0044] As shown in Figures 16 and 17 , the wooden base isolation gaskets 110 of the second embodiment are also interposed between the foundation 1 and the foundation 2 of a building, similar to the first embodiment. The building of the second embodiment differs from the building of the first embodiment in the shape of the wooden base isolation gaskets 110. As shown in Figure 16 , the wooden base isolation gaskets 110 do not have a column and are flat. In this embodiment, the height of the wooden base isolation gaskets 110 is approximately 5 mm. The second embodiment uses a so-called foundation insulation method, in which insulation is applied inside or outside the foundation 1 and the underfloor is mechanically heated or air-conditioned by ventilation, without taking measures against deterioration due to underfloor ventilation as in conventional wooden buildings. In the second embodiment, thin wooden base isolation gaskets 110 are used to prevent internal condensation and provide slit insulation incorporating an air layer of less than 1 cm, which is effective for drying wood.

[0045] As shown in Figures 18 and 19, the wooden base seismic isolation gasket 110 is made of engineering plastic and is rectangular in plan view. Its upper surface forms a smooth surface 114 that contacts the base 2, and its lower surface has multiple protrusions 119 that contact the foundation 1. In this embodiment, the longitudinal dimension of the wooden base seismic isolation gasket 110 is set equal to the distance from the center of the column 3 to the anchor bolt 40. Specifically, the planar dimensions of the wooden base seismic isolation gasket 10 of this embodiment are 100 mm for the short side and 200 mm for the long side. In this embodiment, each protrusion 119 has a truncated cone shape. The shape of each protrusion 119 is optional, and may be, for example, cylindrical, prismatic, or pyramidal. The dimensions of each protrusion 119 are optional, but may be, for example, a height from the bottom surface of 0.2 mm to 0.3 mm, and a diameter of the base end of approximately 1 mm. Each of the protrusions 119 functions as a slip prevention for the foundation 1 in the event of an earthquake. Instead of the protrusions 119, the lower surface may be roughened.

[0046] As shown in FIG. 18 , a first inclined surface 118a sloping downward toward the outside in the normal direction is formed on the outer edge of the top surface of one of the long and short sides, while a second inclined surface 118b, which is steeper than the first inclined surface 118a, is formed on the outer edge of the top surface of the other long and short side. The first and second inclined surfaces 118a and 118b facilitate installation of the wooden foundation seismic isolation gasket 110 by driving it in. The wooden foundation seismic isolation gasket 110 also has an adjustment groove 190 that can accommodate tools. The adjustment groove 190 penetrates the flat portion of the wooden foundation seismic isolation gasket 110 in the thickness direction and extends inward from a predetermined side. In this embodiment, the adjustment groove 190 is formed so that the width dimension at the terminal end is larger than that at the base end. In this embodiment, the adjustment groove 190 also has an inclined surface 190b that is formed continuously with the second inclined surface 118b.

[0047] As shown in Figure 20, in this building, insulation panels 5 are installed on the indoor side of the foundation 1 located on the perimeter. Note that insulation may also be performed on the outdoor side of the foundation 1. Furthermore, foam spray insulation 6 is installed from the top of the insulation panel 5 to the indoor side of the base 2, covering the indoor side of the wooden base seismic isolation packing 110. The wooden base seismic isolation packing 110 of this embodiment is relatively thin, and the slit-shaped space between the base 1 and base 2 provides excellent insulation. To achieve excellent insulation using the wooden base seismic isolation packing 10 with a column, as in the first embodiment, simply reduce the vertical dimension of the column. The foam spray insulation 6 is designed to follow the wooden base seismic isolation packing 110 even if it slides by a few millimeters. If it is slidable in this way, the foam spray insulation 6 may be a dry insulation material. In this embodiment, an elastic spray-type foam insulation material 6 is used as the foam insulation material 6, which utilizes the wood insulation effect to enable monitoring of the wood's decay state and prevents condensation on the concrete surface on the indoor side. The insulation panels 5 and foam insulation material 6 provide insulation, making it less likely for condensation to occur due to the exposed concrete of the foundation 1. Furthermore, the opposite side of the foam insulation material 6 has an open slit to prevent internal condensation on metal such as rebar inside the foundation 1, achieving the effects of air layer insulation and drying the wood. While an example using the insulation panel 5 is shown here, other insulation materials such as insulating spray materials and foaming agents can also be used in addition to dry panels.

[0048] The seismic isolation mechanism for a building equipped with the anchor bolts and wooden base seismic isolation packing of this embodiment can also achieve the same effect as the first embodiment during an earthquake. Furthermore, for example, a modified wooden base seismic isolation packing 210 of the second embodiment shown in FIGS. 21 to 23 can also be used. This wooden base seismic isolation packing 210 is made of engineering plastic and, as shown in FIGS. 21 and 22 , is rectangular in plan view. Its upper surface forms a smooth surface 214 that contacts the base 2, and its lower surface has multiple convex portions 219 that contact the foundation 1. As shown in FIG. 23 , in this wooden base seismic isolation packing 210, each convex portion 219 has a flat base portion 219a that is rectangular in plan view and an inclined portion 219b that slopes upward from the periphery of the base portion 219a. Note that FIG. 22 does not show the inclination of the underside of the wooden base seismic isolation packing 210. Each convex portion 219 functions as a non-slip barrier against the foundation 1 during an earthquake. The shape of the convex portion 219 is arbitrary, and it is also possible to roughen the lower surface instead of the convex portion 219. Also, as shown in Figure 21, a first inclined surface 218a that slopes downward outward in the normal direction is formed on the outer edge of the upper surface of one of the long and short sides, and a second inclined surface 218b that is steeper than the first inclined surface 218a is formed on the outer edge of the upper surface of the other long and short side. The first and second inclined surfaces 218a, 218b make it easy to install the under-wooden foundation seismic isolation packing 210 by driving it in.

[0049] Figures 24 to 32 show a third embodiment of the present invention. Figure 24 is a schematic side view of a building, Figure 25 is a schematic plan view of a building showing the placement of wooden base seismic isolation gaskets, Figure 26 is a bottom view of a first wooden base seismic isolation gasket, Figure 27 is a side cross-sectional view of the first wooden base seismic isolation gasket, Figure 28 is a bottom view of a second wooden base seismic isolation gasket, Figure 29 is a side cross-sectional view of the second wooden base seismic isolation gasket, Figure 30 is a bottom view of a third wooden base seismic isolation gasket, Figure 31 is a side cross-sectional view of the third wooden base seismic isolation gasket, and Figure 32 is a schematic side view of a building showing an insulated state. Note that Figures 24 and 32 are explanatory diagrams, and hatching and other details are omitted. As shown in Figures 24 and 25, three types of wooden base seismic isolation gaskets 310, 320, and 330 are used in this embodiment. In this embodiment, the wooden base isolation packings 310, 320, and 330 are made of a general plastic that has lower strength than engineering plastics. In this embodiment, the wooden base isolation packings 310, 320, and 330 need to be installed over a large area, so they are installed over almost the entire surface between the foundation 1 and the base 2.

[0050] As shown in Figures 26 and 27, the first wooden base seismic isolation gasket 310 is formed in a square shape in a plan view, and is mainly used directly below the columns 3 and at the joints between the base 2 and joists, etc., where cross-sectional defects in the base 2 are likely to occur. As shown in Figures 28 and 29, the second wooden base seismic isolation gasket 320 is shaped so as not to interfere with the anchor bolts 40, 70, and is used in the installation locations of the anchor bolts 40, 70. As shown in Figures 30 and 31, the third wooden base seismic isolation gasket 330 is formed in a rectangular shape in a plan view, and is used in areas other than the locations where the first and second wooden base seismic isolation gaskets 310, 320 are located.

[0051] As shown in Figures 26 and 27, the first wooden foundation seismic isolation packing 310 has a flat plate portion 311 and multiple cylindrical portions 312 protruding downward from the flat plate portion 311. The flat plate portion 311 is formed in a square shape in a plan view, and its upper surface forms a smooth surface 314 that contacts the base 2. The cylindrical portions 312 serving as pillars are aligned vertically and horizontally in a plan view, and their lower surfaces form rough surfaces 315 that contact the foundation 1. The vertical dimension of each cylindrical portion 312 is formed to be larger than that of the flat plate portion 311. Each cylindrical portion 312 functions as a height adjustment portion, and by changing the vertical dimension, the height of the first wooden foundation seismic isolation packing 310 can be changed as desired. In this embodiment, the vertical dimension of each wooden foundation seismic isolation packing 310, 320, and 330 is 19 mm. The vertical dimension of the flat plate portion 311 of the first wooden foundation seismic isolation packing 310 is 5 mm, and the vertical dimension of each cylindrical portion 312 is 14 mm. As shown in FIG. 27 , corners 316 formed by the top and side surfaces of the flat plate portion 311 are chamfered. In this embodiment, the corners 316 are curved with a predetermined curvature, specifically, the radius of curvature of the corners 316 is 2 mm. Note that the corners 316 may be angular rather than rounded. Furthermore, as shown in FIG. 26 , multiple ribs 317 are formed on the underside of the flat plate portion 311. In this embodiment, the flat plate portion 311 is formed with diagonal ribs 317 and linear ribs 317 connecting the midpoints of the opposite sides. Note that each rib 317 may be omitted as appropriate.

[0052] As shown in Figures 28 and 29, the second wooden foundation seismic isolation packing 320 has a flat plate portion 321 and multiple cylindrical portions 322 protruding downward from the flat plate portion 321. The flat plate portion 321 has notches 323 cut inward from the outer edge in plan view to avoid interference with anchor bolts 40, 70. In this embodiment, the notches 323 are rectangularly cut out on one side of the width of each longitudinal end of the foundation 1 and base 2 in the flat plate portion 321, giving the flat plate portion 321 a T-shape in plan view. The flat plate portion 321 has a smooth surface 324 on its upper surface that contacts the base 2. The cylindrical portions 322, which serve as columns, are aligned vertically and horizontally in plan view, and their lower ends form rough surfaces 325 that contact the foundation 1. The vertical dimension of each cylindrical portion 322 is larger than that of the flat plate portion 321. Each cylindrical portion 322 functions as a height adjustment portion, and by changing the vertical dimension, the height of the second wooden foundation under seismic isolation packing 320 can be changed as desired. In this embodiment, the vertical dimension of the flat plate portion 321 is 5 mm, and the vertical dimension of each cylindrical portion 322 is 14 mm. As shown in FIG. 29 , corners 326 formed by the top and side surfaces of the flat plate portion 321 are chamfered. In this embodiment, the corners 326 are curved with a predetermined curvature, and specifically, the radius of curvature of the corners 326 is 2 mm. Note that the corners 326 may be angular rather than rounded.

[0053] As shown in Figures 30 and 31 , the third wooden foundation seismic isolation packing 330 has a flat plate portion 331 and multiple cylindrical portions 332 protruding downward from the flat plate portion 331. The flat plate portion 331 is rectangular in plan view, and its upper surface forms a smooth surface 334 that contacts the base 2. The cylindrical portions 332, which serve as pillars, are aligned vertically and horizontally in plan view, and their lower ends form rough surfaces 335 that contact the foundation 1. The vertical dimension of each cylindrical portion 332 is larger than that of the flat plate portion 331. Each cylindrical portion 332 functions as a height adjustment portion, and by changing the vertical dimension, the height of the third wooden foundation seismic isolation packing 330 can be adjusted as desired. In this embodiment, the vertical dimension of the flat plate portion 331 is 5 mm, and the vertical dimension of each cylindrical portion 332 is 14 mm. 31 , corners 336 formed by the top surface and side surface of flat plate portion 331 are chamfered. In this embodiment, corners 336 are curved with a predetermined curvature, and specifically, the radius of curvature of corners 336 is 2 mm. Note that corners 336 may be angular instead of rounded.

[0054] As shown in FIG. 25 , in principle, either the first wooden base seismic isolation gasket 310, the second wooden base seismic isolation gasket 320, or the third wooden base seismic isolation gasket 330 is installed in all areas on the foundation 1. However, areas where the wooden base seismic isolation gaskets 310, 320, and 330 are not installed can be set in areas where no load is applied, such as the edges of the foundation 1. If the areas on the foundation 1 where the wooden base seismic isolation gaskets 310, 320, and 330 are not installed are located on the periphery, additional rodent-proof material can be installed. In FIG. 25 , for illustrative purposes, the non-installation area 301a is indicated by hatching. As shown in FIG. 25 , the first wooden base seismic isolation gasket 310 is placed in areas on the foundation 1 where a relatively large load is applied. In this embodiment, the first wooden base seismic isolation gasket 310 is placed below all columns 3 on the foundation 1 and below the main underpinnings. Furthermore, the second wooden base seismic isolation gasket 320 is placed at the installation location of the anchor bolts 40, 70 on the foundation 1. The third wooden base seismic isolation gasket 330 is placed in a portion where neither the first wooden base seismic isolation gasket 310 nor the second wooden base seismic isolation gasket 320 is placed. Note that if the first wooden base seismic isolation gasket 310 and the second wooden base seismic isolation gasket 320 are given relatively high strength, the third wooden base seismic isolation gasket 330 can be omitted at will.

[0055] As shown in Figure 32, in the building of this embodiment, an insulating panel 5 is provided on the indoor side of the foundation 1 located on the periphery, and foamed spray insulation material 6 is provided from the upper end of the insulating panel 5 to the indoor side of the base 2, covering the indoor side of the wooden base seismic isolation gaskets 310, 320, and 330.

[0056] The seismic isolation mechanism for a building equipped with the anchor bolts and wooden base seismic isolation packings configured as described above can also achieve the same effect as in the first embodiment during an earthquake. Furthermore, in this embodiment, the second wooden base seismic isolation packing 320 having the notch 323 is disposed near the anchor bolts 40, 70, so that the second wooden base seismic isolation packing 320 can be attached and detached from the outside in the width direction of the base 1 and the foundation 2 without interfering with the anchor bolts 40, 70. This eliminates the need to raise the wooden skeleton of the building by a relatively large amount (for example, about 300 mm) when performing maintenance or replacement of the wooden base seismic isolation packings 310, 320, 330, and thus avoids incurring huge costs.

[0057] In addition, first wooden base seismic isolation gaskets 310, which are square in plan view, are placed below all columns 3. This ensures the pressure resistance of the column portions, which are subject to a relatively large axial force. Meanwhile, for portions other than below the columns 3, second wooden base seismic isolation gaskets 320 are placed in the portions where anchor bolts 40, 70 are placed, and third wooden base seismic isolation gaskets 330 are placed in the portions where anchor bolts 40, 70 are not placed. In this way, by using a set of wooden base seismic isolation gaskets including the second wooden base seismic isolation gasket 320 with the cutout 323 and the first wooden base seismic isolation gasket 310 and the third wooden base seismic isolation gasket 330 without the cutout 323, it is possible to accommodate both the corner portions and the middle portions of the foundation 1 in plan view.

[0058] In the above embodiment, the undersides of the wooden foundation seismic isolation packings 310, 320, and 330 are roughened surfaces 315, 325, and 335, respectively. However, as shown in FIGS. 33 and 34, instead of forming a roughened surface, the undersides may have multiple convex portions 319 that contact the foundation 1. In this modification, as shown in FIGS. 33(b) and 34(b), multiple convex portions 319 are formed at equal intervals in the circumferential direction on the underside of the cylindrical portion 312. While FIGS. 33(b) and 34(b) show an example in which each convex portion 319 is frustum-shaped, the shape of each convex portion 319 may be any shape, such as a cylindrical, prismatic, or truncated pyramidal shape. The dimensions of the convex portions 319 may also be any shape, such as a height from the underside of 0.2 mm to 0.3 mm, and a diameter of the base end of the convex portion 319 of approximately 1 mm.

[0059] In the first and third embodiments and their modifications, the columnar portions extending downward from the flat plate portions 11, 81, 311, 321, 331 are shown as cylindrical portions 12, 312, 322, 332 or columnar portions 82, but they may also be, for example, polygonal tubes or polygonal columns. The shape, dimensions, arrangement, etc. of the columnar portions can be appropriately changed depending on, for example, the ventilation rate, airtightness, etc., within a range in which strength against the applied load is ensured.

[0060] Figures 35 to 41 show a fourth embodiment of the present invention, where Figure 35 is a schematic side view of a building, Figure 36 is a top view of the first wooden base seismic isolation gasket, and Figure 37 is a side view of the first wooden base seismic isolation gasket. Figure 38 is a top view of the second wooden base seismic isolation gasket, Figure 39 is a side view of the second wooden base seismic isolation gasket, Figure 40 is a top view of the third wooden base seismic isolation gasket, and Figure 41 is a side view of the third wooden base seismic isolation gasket. Note that Figure 35 is an explanatory diagram, and hatching and the like are omitted. In the fourth embodiment, flat wooden base seismic isolation gaskets 410, 420, and 430 without column portions as shown in Figures 35 to 41 are used.

[0061] As shown in Figures 37 and 38, the first wooden base seismic isolation gasket 410 of the fourth embodiment is made of metal and has a square shape in a plan view. The upper surface forms a smooth surface 414 that contacts the base 2, and the lower surface has multiple protrusions 419 that contact the foundation 1. The first wooden base seismic isolation gasket 410 is specifically made of stainless steel. In this specification, "metal" also includes alloys such as stainless steel. As shown in Figure 38(b), each protrusion 419 is formed in a truncated cone shape, and may have a height from the lower surface of 0.2 mm to 0.3 mm and a base diameter of approximately 1 mm. Each protrusion 419 functions as a non-slip surface for the foundation 1 during an earthquake. A rough surface may be used instead of the protrusions 419. Furthermore, an inclined surface 418 that slopes downward toward the outside in the normal direction is formed on the outer edge of the upper surface of a predetermined side. The inclined surface 418 makes it easy to install the first wooden foundation seismic isolation gasket 410 by driving it in.

[0062] As shown in Figures 39 and 40 , the second wooden base seismic isolation gasket 420 of the fourth embodiment is made of metal, has a smooth surface 424 on its upper surface that contacts the base 2, and has multiple protrusions 429 on its lower surface that contact the foundation 1. Specifically, the second wooden base seismic isolation gasket 420 is made of stainless steel. Each protrusion 429 is formed in a truncated cone shape, with a height from the lower surface of 0.2 mm to 0.3 mm and a base end diameter of approximately 1 mm, for example. Each protrusion 429 functions as a non-slip surface for the foundation 1 during an earthquake. Note that a rough surface may be used instead of the protrusions 429. The cutouts 423 of the second wooden base seismic isolation gasket 420 are shaped like a rectangle cutout on one side of the width direction at both longitudinal ends of the foundation 1 and the base 2, and the second wooden base seismic isolation gasket 420 is T-shaped in plan view. In addition, an inclined surface 428 that slopes downward in one direction in the width direction is formed on the outer edge of one widthwise end of the top surface on the longitudinal center side. The inclined surface 428 makes it easy to install the second wooden foundation under-seismic isolation packing 420 by driving it in. In addition, a corner 426 at one widthwise end of the top surface on the longitudinal center side is curved with a predetermined curvature.

[0063] As shown in Figures 41 and 42, the third wooden base seismic isolation gasket 430 of the fourth embodiment is made of metal and has a rectangular shape in a plan view. The upper surface forms a smooth surface 434 that contacts the base 2, and the lower surface has multiple protrusions 439 that contact the foundation 1. Each protrusion 439 is formed in a truncated cone shape, for example, with a height from the lower surface of 0.2 mm to 0.3 mm and a base end diameter of approximately 1 mm. The third wooden base seismic isolation gasket 430 is specifically made of stainless steel. Each protrusion 439 functions as a non-slip surface against the foundation 1 during an earthquake. A rough surface may be used instead of the protrusions 439. In addition, an inclined surface 438 that slopes downward toward the outside in the normal direction is formed on the outer edge of the upper surface of a predetermined long side. The inclined surface 438 facilitates installation by driving the third wooden base seismic isolation gasket 430 into the base. The seismic isolation effect can also be obtained by using the flat wooden base seismic isolation packings 410, 420, 430 shown in Figures 36 to 42.

[0064] The wooden base isolation packings 10, 80, 110, 210, 310, 320, 330, 410, 420, and 430 may be manufactured specifically for the seismic isolation mechanism of a building, or may be manufactured by processing known parts. For example, the wooden base isolation packings 10, 80, 110, 210, 310, 320, 330, 410, 420, and 430 may be manufactured by smoothing the top surface of a known foundation packing.

[0065] Although the embodiments of the present invention have been described above, the invention according to the claims is not limited to the above-described embodiments. It should be noted that not all of the combinations of features described in the embodiments are necessarily essential to the means for solving the problems of the invention.

[0066] REFERENCE SIGNS LIST 1 Foundation 2 Base 3 Column 4 Hold-down hardware 5 Insulation panel 6 Sprayed foam insulation 10 Wooden base seismic isolation packing 11 Flat plate portion 12 Cylindrical portion 14 Smooth surface 16 Corner portion 17 Rib 19 Convex portion 40 Anchor bolt 50 Through hole 60 Nut 61 Long nut portion 62 Round seat 63 Triangular protrusion 70 Anchor bolt 80 Wooden base seismic isolation packing 81 Flat plate portion 81a Inclined portion 81b Inclined portion 81c Flat portion 82 Cylindrical portion 82a Slit 82b Protruding portion 84 Smooth surface 85 Rough surface 86 Corner portion 89 Cylindrical portion 89a Slit 110 Wooden base seismic isolation packing 114 Smooth surface 118a First inclined surface 118b Second inclined surface 119 Convex portion 162 Washer 190 Adjustment groove 190b Inclined surface 210 Under-wooden foundation seismic isolation gasket 214 Smooth surface 218a First inclined surface 218b Second inclined surface 219 Convex portion 219a Base portion 219b Inclined portion 262 Washer 310 First under-wooden foundation seismic isolation gasket 311 Flat plate portion 312 Cylindrical portion 314 Smooth surface 315 Rough surface 316 Corner portion 317 Rib 319 Convex portion 320 Second under-wooden foundation seismic isolation gasket 321 Flat plate portion 322 Cylindrical portion 323 Notch portion 324 Smooth surface 325 Rough surface 326 Corner portion 330 Third under-wooden foundation seismic isolation gasket 331 Flat plate portion 332 Cylindrical portion 334 Smooth surface 335 Rough surface 336 Corner portion 362 Washer 362a Insertion hole 362b Flat portion 362c Protruding portion 410 First wooden base under seismic isolation gasket 414 Smooth surface 418 Inclined surface 419 Convex portion 420 Second wooden base under seismic isolation gasket 423 Notch portion 424 Smooth surface 426 Corner portion 428 Inclined surface 429 Convex portion 430 Third wooden base under seismic isolation gasket 434 Smooth surface 438 Inclined surface 439 Convex portion

Claims

1. A seismic isolation gasket that is inserted between the foundation and base of a building, and in the event of an earthquake, the contact surface with the base slides, while the contact surface with the base does not slide.

2. A seismic isolation gasket for under wooden foundations as described in claim 1, wherein the upper surface in contact with the foundation is a smooth surface, and the lower surface in contact with the base has a convex portion or is a rough surface.

3. A seismic isolation gasket for under wooden foundations as described in claim 2, having a flat plate portion extending horizontally and a plurality of column portions extending downward from the flat plate portion.

4. A seismic isolation gasket for under wooden foundations as described in claim 3, wherein each of the pillars has a ventilation section that allows air to flow horizontally.

5. The seismic isolation gasket for wooden foundations according to claim 1, which is made of plastic.

6. The seismic isolation gasket for under wooden foundations according to claim 5, which is made of engineering plastic.

7. The seismic isolation gasket for wooden foundations according to claim 1, which is made of metal.

8. A seismic isolation gasket for under wooden foundations as described in claim 1, having a notch that is cut inward from the outer edge when viewed in a plane, to avoid interference with anchor bolts.

9. A seismic isolation mechanism for a building comprising: a foundation into which an anchor bolt is buried; a base having a through hole into which the anchor bolt is inserted; and a wooden base seismic isolation gasket described in any one of claims 1 to 7 interposed between the foundation and the base.

10. The seismic isolation mechanism for a building as described in claim 9, wherein the difference between the diameter of the through hole and the diameter of the anchor bolt is 10 mm or more.

11. A method for fastening an anchor bolt to a nut comprising: a foundation, an anchor bolt extending upward from the foundation, a base made of wood arranged above the foundation, a through hole formed in the base and through which the anchor bolt is inserted, a washer inserted into the anchor bolt and in contact with the upper surface of the base, and a nut screwed onto the upper end side of the anchor bolt, wherein a predetermined clearance is secured between a wall surface of the through hole and the anchor bolt, the washer having a flat portion in which a through hole for the anchor bolt is formed, and a protruding portion formed on the outer edge of the flat portion and protruding downward from the flat portion, the washer inserted into the anchor bolt is placed on the upper surface of the base, and the nut screwed onto the anchor bolt is tightened to move the washer downward, thereby driving at least a portion of the protruding portion into the base.

12. A fastening structure for an anchor bolt and a nut comprising: a foundation; an anchor bolt extending upward from the foundation; a base made of wood and arranged above the foundation; a through hole formed in the base and through which the anchor bolt is inserted; a washer inserted into the anchor bolt and in contact with an upper surface of the base; and a nut screwed onto the upper end side of the anchor bolt, wherein a predetermined clearance is ensured between a wall surface of the through hole and the anchor bolt, wherein the washer has a flat portion in which an insertion hole for the anchor bolt is formed, and a protruding portion formed on the outer edge of the flat portion and protruding downward from the flat portion, wherein the protruding portion is embedded into the base, and the flat portion is in contact with the upper surface of the base.

13. A washer for use in a fastening structure of an anchor bolt and a nut which has a foundation, an anchor bolt extending upward from the foundation, a base made of wood and arranged above the foundation, a through hole formed in the base and through which the anchor bolt is inserted, a washer which is inserted by the anchor bolt and contacts the upper surface of the base, and a nut which screws into the upper end of the anchor bolt, wherein a predetermined clearance is secured between a wall surface of the through hole and the anchor bolt, the washer having a flat portion in which an insertion hole for the anchor bolt is formed, and a protruding portion which is formed on the outer edge of the flat portion and protrudes downward from the flat portion, the washer being configured so that when the anchor bolt is inserted through the washer and placed on the upper surface of the base and moved downward by tightening the nut which screws into the anchor bolt, at least a portion of the protruding portion is embedded into the base.

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