Base isolation foundation structure, and construction method of the same

Abstract

To provide a base isolation foundation structure in which a base isolation foundation part to be placed on a plurality of base isolation devices can be constructed with high precision in a short construction period.SOLUTION: A base isolation foundation structure 1 includes a plurality of base isolation devices 20 and an upper base isolation foundation 30 made of reinforced concrete and provided on the plurality of base isolation devices 20. The upper base isolation foundation 30 comprises: a lower precast concrete member 31; a middle precast concrete member 32 placed on the lower precast concrete member 31; and a lower horizontal joint portion 34 formed by filling a space between the lower precast concrete member 31 and the middle precast concrete member 32 with grout material. The base isolation devices 20 and the upper base isolation base 30 are joined via anchor bolts 42.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a seismic isolation foundation structure including a plurality of seismic isolation devices and a seismic isolation foundation portion made of reinforced concrete, and a method for constructing the same. [Background technology]

[0002] 2. Description of the Related Art Joint structures for precast concrete members (PC members) have been available in the past (see Patent Documents 1 to 3). Patent Document 1 shows a connection structure between precast concrete members. Opposing cylindrical joints are embedded in the ends of each precast concrete member, and relay rebars are inserted into the joints. The relay rebars cross the joint spaces between the precast concrete members. Mortar is filled inside the joints and into the joint spaces, connecting the precast concrete members to each other.

[0003] Patent Document 2 shows a precast concrete column joining method for joining a precast concrete column onto a slab. The precast concrete column has a plurality of built-in sleeve-type reinforcing bar joint members. This method includes the steps of arranging a precast concrete column with a joint space provided between the column and the slab, arranging an air tube formwork (separating member) in the joint space to separate the space and form a plurality of divided joint spaces, filling one divided joint space with grout via the sleeve-type reinforcing bar joint member and curing the space, removing the air tube formwork (separating member) after curing of the filled grout is completed, and filling other divided joint spaces with grout via the sleeve-type reinforcing bar joint member and curing the space. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6151740 [Patent Document 2] JP 2020-133158 A Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a seismic isolation foundation structure and a construction method thereof that enable a seismic isolation foundation portion to be placed on a plurality of seismic isolation devices to be constructed with high precision in a short construction period. [Means for solving the problem]

[0006] The inventors have arrived at the present invention by focusing on the fact that a seismic isolation foundation structure including a plurality of seismic isolation devices and a seismic isolation foundation portion provided on these seismic isolation devices can be constructed accurately in a short period of time without pouring concrete at the construction site by stacking a lower precast concrete member and an upper precast concrete member in the seismic isolation foundation portion and forming a horizontal joint portion consisting of a pre-filled portion and a post-constructed filled portion between the lower precast concrete member and the upper precast concrete member. A seismic isolation foundation structure of a first invention (for example, seismic isolation foundation structure 1 described later) is a seismic isolation foundation structure including a plurality of seismic isolation devices (for example, seismic isolation devices 20 described later) and a reinforced concrete seismic isolation foundation portion (for example, upper seismic isolation foundation 30 described later) provided on the plurality of seismic isolation devices, the seismic isolation foundation portion including a lower precast concrete member (for example, lower precast concrete member 31 and middle precast concrete member 32 described later), an upper precast concrete member (for example, middle precast concrete member 32 and upper precast concrete member 33 described later) disposed on the lower precast concrete member, and horizontal joint portions (for example, lower horizontal joint portion 34 and upper horizontal joint portion 35 described later) formed by filling a filler between the lower precast concrete member and the upper precast concrete member, and the plurality of seismic isolation devices and the seismic isolation foundation portion are joined via anchor bolts (for example, anchor bolts 42 described later).

[0007] According to this invention, the seismic isolation foundation to be installed on the multiple seismic isolation devices is formed by stacking multiple precast concrete members. Therefore, the seismic isolation foundation can be constructed accurately in a short construction period without pouring concrete at the construction site. In addition, in the seismic isolation foundation structure, the multiple seismic isolation devices and the seismic isolation foundation are joined with anchor bolts, which has the effect of absorbing the seismic force generated by an earthquake and protecting the building from shaking. In addition, by dividing the seismic isolation foundation into multiple precast concrete components, each precast concrete component can be made lighter, improving the ease of handling when transporting and installing the precast concrete components.

[0008] The method for constructing a seismic isolation foundation structure according to the second aspect of the present invention is a method for constructing a seismic isolation foundation structure by joining a plurality of seismic isolation devices (e.g., seismic isolation devices 20 described later) and a reinforced concrete seismic isolation foundation part (e.g., upper seismic isolation foundation 30 described later) provided on the plurality of seismic isolation devices, and the seismic isolation foundation part is formed by stacking a lower precast concrete member (e.g., lower precast concrete member 31 described later), a horizontal joint part (e.g., lower horizontal joint part 34 described later), and an upper precast concrete member (e.g., upper precast concrete member 33 described later) in this order from the bottom. The method includes a step of installing the plurality of seismic isolation devices (e.g., step S2 described below), a step of placing the lower precast concrete member on the plurality of seismic isolation devices and fixing the seismic isolation devices and the lower precast concrete member with bolts (e.g., bolts 26 described below) (e.g., step S3 described below), a step of placing the upper precast concrete member on the lower precast concrete member with a predetermined gap (e.g., gap P described below) (e.g., step S4 described below), and a step of fixing the lower precast concrete member and the upper precast concrete member with a predetermined gap (e.g., gap P described below). and a step (e.g., step S5 described later) of pressurizing a filler into the gap between the lower precast concrete member and the upper precast concrete member to form a horizontal joint (e.g., lower horizontal joint 34 described later). The step of forming the horizontal joint includes a step (e.g., step S11 described later) of erecting a preliminary formwork (e.g., outer peripheral formwork 75, air formwork 76 described later) surrounding a predetermined range of the gap between the lower precast concrete member and the upper precast concrete member, and a step (e.g., step S12 described later) of injecting a filler into the gap between the lower precast concrete member and the upper precast concrete member through an injection hole (e.g., injection hole 36 described later) provided inside the upper precast concrete member. The method includes a process (e.g., step S12 described below) of pressing filler into the area surrounded by the formwork to form a pre-filled portion (e.g., pre-filled portion 34A described below), a process (e.g., step S13 described below) of removing the pre-filled formwork after the filling material has hardened and surrounding the remaining area of ​​the gap with a post-construction formwork (e.g., outer peripheral formwork 77 described below), and a process (e.g., step S14 described below) of pressing filler into the area surrounded by the post-construction formwork to form a post-construction filling portion (e.g., post-construction filling portion 34B described below) to complete the horizontal joint portion.

[0009] According to this invention, the seismic isolation base portion provided on the plurality of seismic isolation devices is formed by stacking a plurality of precast concrete members. Therefore, the seismic isolation base portion can be constructed accurately in a short construction period without pouring concrete at the construction site. In addition, by dividing the seismic isolation foundation into multiple precast concrete components, each precast concrete component can be made lighter, improving the ease of handling when transporting and installing the precast concrete components. In addition, because the base isolation foundation covers multiple base isolation devices, the planar area of ​​the horizontal joints that make up the base isolation foundation becomes large. Therefore, according to this invention, the horizontal joints are divided into a pre-filling section and a post-construction filling section, so that the filler can be filled easily and quickly, and the horizontal joints can be constructed quickly. Furthermore, the voids that occur inside the horizontal joints can be reduced.

[0010] The method of constructing a seismic isolation foundation structure of the third invention is characterized in that the injection hole extends from the side of the upper precast concrete member to the center of each of the advance filling portion and the post-construction filling portion of the upper precast concrete member, the lower precast concrete member is provided with a reinforcing bar (e.g., reinforcing bar 43 described below) that protrudes upward, the upper precast concrete member is provided with a reinforcing bar joint (e.g., reinforcing bar joint 50 described below) into which the reinforcing bar protruding from the lower precast concrete member is inserted, and a discharge hole (e.g., discharge hole 37 described below) is provided from the reinforcing bar joint to the side of the upper precast concrete member.

[0011] According to this invention, an upper precast concrete member is placed above a lower precast concrete member with a predetermined gap therebetween, and the reinforcing bars protruding from the lower precast concrete member are inserted into the reinforcing bar joints of the upper precast concrete member. Then, filler is pressed into the gap between the lower and upper precast concrete members through the injection hole, and the filler is pressed into the reinforcing bar joints and discharged from the discharge hole. This forms a horizontal joint, and the reinforcing bars of the lower precast concrete member are joined to the reinforcing bar joints of the upper precast concrete member by the reinforcing bar joints. Thus, the lower precast concrete member and the upper precast concrete member are firmly joined. Effect of the Invention

[0012] According to the present invention, it is possible to provide a seismic isolation foundation structure and a construction method thereof, which can construct a seismic isolation foundation portion to be placed on a plurality of seismic isolation devices with high accuracy in a short construction period. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a side view of the seismic isolation foundation structure according to the first embodiment of the present invention. [Diagram 2] 2 is a cross-sectional view of the seismic isolation foundation structure shown in FIG. 1 . [Diagram 3] FIG. 2 is a cross-sectional view of the seismic isolation foundation structure of FIG. 1 . [Figure 4] FIG. 2 is a CC cross-sectional view of the seismic isolation foundation structure of FIG. 1. [Diagram 5] 1 is a flowchart of a procedure for constructing a seismic isolation foundation structure. [Figure 6] This is an explanatory diagram of the construction procedure for a seismic isolation foundation structure (Part 1, the state after the lower seismic isolation foundation has been constructed on the floor surface). [Figure 7] This is an explanatory diagram of the construction procedure for a seismic isolation foundation structure (part 2, with the seismic isolation device installed on the lower seismic isolation foundation). [Figure 8] This is an explanatory diagram of the construction procedure for a seismic isolation foundation structure (part 3, the state in which the lower precast concrete member is installed on the seismic isolation device). [Figure 9] This is an explanatory diagram of the construction procedure for a seismic isolation foundation structure (Part 4, the state in which the middle precast concrete member is installed on the lower precast concrete member). [Figure 10] 13 is a flowchart of a procedure for forming a lower horizontal joint portion. [Figure 11] This is a plan view of the gap between the lower tier precast concrete member and the middle tier precast concrete member. [Figure 12] 12A and 12B are vertical cross-sectional views of a portion surrounded by a dashed line D and a portion surrounded by a dashed line E of the gap in FIG. 11. [Figure 13] 12A and 12B are a vertical sectional view and a side view of a portion of the gap surrounded by a dashed line F in FIG. 11. [Figure 14] An explanatory diagram of the procedure for forming the lower horizontal joint portion (after the pre-filling portion has been formed). [Figure 15] FIG. 1 is a vertical cross-sectional view of a seismic isolation foundation structure according to a first embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention relates to a seismic isolation foundation structure including a plurality of seismic isolation devices and a seismic isolation foundation provided on the seismic isolation devices. The seismic isolation foundation is constructed by stacking a lower precast concrete member and an upper precast concrete member, and forming a horizontal joint portion consisting of a pre-filled portion and a post-construction filled portion between the lower precast concrete member and the upper precast concrete member. Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description of the embodiments, the same components are denoted by the same reference numerals, and the description thereof will be omitted or simplified. [First embodiment] Fig. 1 is a side view of a seismic isolation foundation structure 1 according to a first embodiment of the present invention. Fig. 2 is an AA cross-sectional view of the seismic isolation foundation structure 1 in Fig. 1. Fig. 3 is a BB cross-sectional view of the seismic isolation foundation structure 1 in Fig. 1. Fig. 4 is a CC cross-sectional view of the seismic isolation foundation structure 1 in Fig. 1. The seismic isolation foundation structure 1 is a seismic isolation foundation for a building, and includes a lower seismic isolation foundation 10 made of reinforced concrete and installed on the floor surface 2, two seismic isolation devices 20 installed on the lower seismic isolation foundation 10, and an upper seismic isolation foundation 30 as a seismic isolation foundation part made of reinforced concrete and installed on the two seismic isolation devices 20. As shown by the dashed line in FIG. 1, reinforced concrete beams 3 are constructed on the sides of the upper seismic isolation foundation 30, and precast reinforced concrete columns 4 are provided on the top surface of the upper seismic isolation foundation 30.

[0015] The lower seismic isolation foundation 10 is made of precast reinforced concrete, and a lower base plate 11 is driven into the upper surface of the lower seismic isolation foundation 10. Female threads 12 are provided in a circular shape at predetermined intervals on the lower base plate 11. Anchor bolts 13 are screwed into the lower ends of the female threads 12, and extend downward from the lower seismic isolation foundation 10.

[0016] The seismic isolation device 20 comprises a laminated rubber 21 , a lower flange 22 located below the laminated rubber 21 , and an upper flange 23 located above the laminated rubber 21 . The laminated rubber 21 is made up of steel plates and rubber laminated alternately. The upper and lower flanges 22, 23 are provided with bolt insertion holes 24, 25 for inserting bolts at predetermined intervals along the periphery. A bolt 26 is inserted into the bolt insertion hole 24 of the lower flange 22 and is screwed into the female thread portion 12 provided in the lower base plate 11 of the lower seismic isolation foundation 10.

[0017] The upper seismic isolation foundation 30 comprises a lower stage precast concrete member 31, a middle stage precast concrete member 32 placed on the lower stage precast concrete member 31, and an upper stage precast concrete member 33 placed on the middle stage precast concrete member 32. A lower horizontal joint 34 is formed between the lower stage precast concrete member 31 and the middle stage precast concrete member 32. An upper horizontal joint 35 is formed between the middle stage precast concrete member 32 and the upper stage precast concrete member 33.

[0018] The design strength Fc (N / mm 2 ) are all set to be the same, for example, Fc100, Fc80, Fc70, Fc60, and Fc48.

[0019] An upper base plate 40 is driven into the underside of the lower precast concrete member 31. Female threads 41 are provided in an annular shape at predetermined intervals on this upper base plate 40. Anchor bolts 42 are screwed into the upper ends of these female threads 41. Bolts 27 are screwed into the bolt insertion holes 25 of the upper flange 23 of the seismic isolation device 20, and are screwed into the female threads 41 provided on the upper base plate 40. Furthermore, reinforcing bars 43 are arranged inside the lower precast concrete member 31, and these reinforcing bars 43 protrude upward from the top surface of the lower precast concrete member 31. In addition, the lower main beam reinforcement 44 of the beam 3 protrudes from the side surface of the lower precast concrete member 31.

[0020] Reinforcing bar joints 50, 51 are embedded in the upper and lower surfaces of the middle-stage precast concrete member 32. Reinforcing bars 52 are arranged inside the middle-stage precast concrete member 32, and these reinforcing bars 52 are joined to the reinforcing bar joints 50, 51. The reinforcing bar 43 protruding upward from the lower precast concrete member 31 penetrates the lower horizontal joint portion 34 and is inserted into the reinforcing bar joint 50 of the middle precast concrete member 32, and is joined to the reinforcing bar joint 50 by injecting grout material as a filler.

[0021] Reinforcing bars 60 are arranged inside the upper precast concrete member 33, and these reinforcing bars 60 protrude downward from the underside of the upper precast concrete member 33. The reinforcing bar 60 protruding downward from the upper precast concrete member 33 is inserted through the upper horizontal joint portion 35 into the reinforcing bar joint 51 of the middle precast concrete member 32, and is fixed to the reinforcing bar joint 51 by injecting grout material as a filler. In addition, upper beam main reinforcement 61 of beam 3 protrudes from the side surface of upper precast concrete member 33, and column main reinforcement 62 of column 4 protrudes from the top surface of upper precast concrete member 33.

[0022] As shown in FIG. 2, the lower horizontal joint portion 34 is formed in two stages, a pre-filling portion 34A and a post-construction filling portion 34B. The middle stage precast concrete component 32 has injection holes 36 formed therein, which extend from the side surface of the middle stage precast concrete component 32 to the center of each of the advance filling section 34A and the post-construction filling section 34B of the middle stage precast concrete component 32. The middle stage precast concrete component 32 also has discharge holes 37 formed therein, which extend from the reinforcing bar joints 50 to the side surface of the middle stage precast concrete component 32.

[0023] The upper horizontal joint portion 35 is also formed in two stages, a pre-filling portion 35A and a post-installation filling portion 35B. The upper precast concrete member 33 has an injection hole 38 and a discharge hole 39 formed from the side of the upper precast concrete member 33 to the center of each of the pre-filled portion 35A and the post-construction filled portion 35B of the upper precast concrete member 33.

[0024] The construction procedure of the seismic isolation foundation structure 1 will be described below with reference to the flow chart of FIG. In step S1, as shown in Fig. 6, a lower seismic isolation foundation 10 is constructed on the floor surface 2. Specifically, a recess 5 is formed in the floor surface 2, and the lower seismic isolation foundation 10 made of precast reinforced concrete is provided on this recess 5. Anchor bolts 13 protrude from the lower end surface of the lower seismic isolation foundation 10. In this state, concrete is poured into the recess 5 to form a concrete body 6, whereby the anchor bolts 13 protruding from the lower end surface of the lower seismic isolation foundation 10 are embedded in the concrete body 6, and the lower seismic isolation foundation 10 is fixed onto the floor surface 2. In this embodiment, the lower seismic isolation foundation 10 is made of precast reinforced concrete, but the present invention is not limited to this and the lower seismic isolation foundation may be constructed by arranging reinforcement and pouring concrete on-site. In step S2, as shown in Fig. 7, two seismic isolation devices 20 are installed on the lower seismic isolation foundation 10. Specifically, the two seismic isolation devices 20 are placed on the lower seismic isolation foundation 10, and bolts 26 are inserted into the bolt insertion holes 24 of the lower flanges 22 of the seismic isolation devices 20 and screwed into the female threaded portions 12 provided on the lower base plate 11 of the lower seismic isolation foundation 10.

[0025] In step S3, as shown in Fig. 8, the lower precast concrete member 31 is placed on the two seismic isolation devices 20. Specifically, the lower precast concrete member 31 is placed on the two seismic isolation devices 20. Next, the bolt 27 is inserted into the bolt insertion hole 25 of the upper flange 23 of the seismic isolation device 20 and screwed into the female thread portion 41 provided on the upper base plate 40 of the lower precast concrete member 31. In step S4, as shown in Figure 9, the middle stage precast concrete member 32 is placed on the lower stage precast concrete member 31 with a specified gap P therebetween. As a result, the reinforcing bars 43 protruding upward from the lower stage precast concrete member 31 are inserted into the reinforcing bar joints 50 of the middle stage precast concrete member 32.

[0026] 9, grout material is pressed into gap P between the lower stage precast concrete member 31 and the middle stage precast concrete member 32 to form lower horizontal joint 34. At this time, the pressed grout material is also filled into reinforcing bar joint 50, and reinforcing bar 43 of lower stage precast concrete member 31 is joined to reinforcing bar joint 50 of middle stage precast concrete member 32. In step S6, as shown in Fig. 4, the upper stage precast concrete member 33 is placed on the middle stage precast concrete member 32 with a specified gap therebetween. As a result, the reinforcing bars 60 protruding downward from the upper stage precast concrete member 33 are inserted into the reinforcing bar joints 51 of the middle stage precast concrete member 32. 4, grout material is pressed into the gap between the middle-stage precast concrete member 32 and the upper-stage precast concrete member 33 to form the upper horizontal joint 35. At this time, the pressed grout material is also filled into the interior of the reinforcing bar joints 51, and the reinforcing bars 60 of the upper-stage precast concrete member 33 are joined to the reinforcing bar joints 51 of the middle-stage precast concrete member 32.

[0027] The procedure for forming the lower horizontal joint 34 by pressing the grout material into the gap P will be described in detail below with reference to the flowchart in Fig. 10. Note that although the procedure for forming the lower horizontal joint 34 will be described below, the upper horizontal joint 35 is also formed in the same manner. Fig. 11 is a plan view of gap P between lower stage precast concrete member 31 and middle stage precast concrete member 32. Fig. 12(a) is a vertical cross-sectional view of a portion of gap P surrounded by dashed line D in Fig. 10. Fig. 12(b) is a vertical cross-sectional view of a portion of gap P surrounded by dashed line E in Fig. 10. Fig. 13 is a vertical cross-sectional view and a side view of a portion of gap P surrounded by dashed line F in Fig. 10.

[0028] In the above-mentioned step S4, as shown in FIG. 12(a), a female threaded portion 70 is embedded in the upper surface of the lower precast concrete member 31, and a bolt receiving plate 71 is embedded in the lower surface of the middle precast concrete member 32. Then, a bolt 72 is screwed into the female threaded portion 70 of the lower precast concrete member 31, and the protruding dimension of the bolt 72 from the lower precast concrete member 31 is set to the height dimension of the gap P. Next, the middle precast concrete member 32 is lifted up by a crane or the like and lowered onto the lower precast concrete member 31. Then, the upper surface of the head of the bolt 72 comes into contact with the receiving plate 71 of the middle precast concrete member 32, and the load of the middle precast concrete member 32 is supported by the bolt 72, and a gap P is formed between the lower precast concrete member 31 and the middle precast concrete member 32.

[0029] First, in step S11, as shown in Fig. 11, an outer peripheral form 75 and an air form 76 are erected as preliminary formworks, surrounding the area that will become the preliminary filling portion 34A of the gap P. Here, the outer peripheral form 75 is erected along the outer peripheral side surfaces of the lower stage precast concrete member 31 and the middle stage precast concrete member 32. Meanwhile, the air form 76 is erected at the boundary between the preliminary filling portion 34A and the post-construction filling portion 34B of the gap P, and expands when air is filled inside. Additionally, anti-floating hardware 80 is attached. Anti-floating hardware 80 comprises a lower hardware 81 temporarily fixed to the side of lower precast concrete member 31 with bolts 84, an upper hardware 82 temporarily fixed to the side of middle precast concrete member 32 with bolts 85, and a connecting member 83 connecting lower hardware 81 and upper hardware 82.

[0030] In step S12, as shown in Fig. 11, grout material is injected into the area surrounded by the outer peripheral formwork 75 and the air formwork 76 through the injection hole 36 provided inside the middle-stage precast concrete member 32 to form the advance filling portion 34A. The grout material is injected until the grout material is filled inside the reinforcing bar joint 50 and discharged from the discharge hole 37. At this time, the filling material spreads from the center of the underside of the middle-stage precast concrete member 32 through the injection hole 36 toward the four corners, so that the time it takes for the filling material to reach the four corners of the middle-stage precast concrete member 32 is approximately equal. When forming the upper horizontal joint portion 35, in step S12, grout material is injected into the area surrounded by the outer peripheral formwork 75 and the air formwork 76 through injection hole 38 provided inside the upper precast concrete member 33 to form pre-filled portion 35A. The grout material is injected until it is discharged from discharge hole 39 provided inside the upper precast concrete member 33 (see Figures 3 and 4).

[0031] In step S13, as shown in FIG. 14, after the grout material has hardened, the outer peripheral formwork 75 and the air formwork 76 of the advance filling section 34A are removed, and an outer peripheral formwork 77 as a post-construction formwork is erected to surround the remaining area of ​​the gap P, i.e., the area that will become the post-construction filling section 34B. In step S14, as shown in FIG. 14, grout material is pressed into the area surrounded by the outer peripheral formwork 77 to form the post-installed filling portion 34B, thereby completing the lower horizontal joint portion 34. In step S15, the outer peripheral formwork 77, which is the formwork for the post-installation filling section 34B, is removed.

[0032] According to this embodiment, the following effects are obtained. (1) The upper seismic isolation foundation 30, which is placed on top of the two seismic isolation devices 20, is formed by stacking three precast concrete members 31 to 33. Therefore, the upper seismic isolation foundation 30 can be constructed accurately in a short construction period without pouring concrete at the construction site. Also, in the seismic isolation foundation structure 1, the multiple seismic isolation devices 20 and the lower precast concrete members 31 are joined with anchor bolts 42, which has the effect of absorbing the seismic force generated by an earthquake and protecting the building from shaking. Furthermore, by dividing the upper seismic isolation base 30 into three stages of precast concrete members 31-33, the weight of each precast concrete member 31-33 can be reduced, improving the ease of handling, such as transportation and installation, of the precast concrete members 31-33.

[0033] (2) Since the upper seismic isolation foundation 30 covers the two seismic isolation devices 20, the planar area of ​​the horizontal joints 34, 35 that constitute the upper seismic isolation foundation 30 becomes large. Therefore, by constructing the horizontal joints 34, 35 in two, the filler can be filled easily and quickly, and the horizontal joints 34, 35 can be constructed quickly. Furthermore, the voids that occur inside the horizontal joints 34, 35 can be reduced. (3) The middle precast concrete member 32 is placed above the lower precast concrete member 31 with a specified gap P therebetween, and the reinforcing bars 43 protruding from the lower precast concrete member 31 are inserted into the reinforcing bar joints 50 of the middle precast concrete member 32. Then, grout material is pressed into the gaps P through the injection holes 36, and the grout material is pressed into the reinforcing bar joints 50 and discharged from the discharge holes 37. This forms the lower horizontal joint 34, and the reinforcing bars 43 of the lower precast concrete member 31 are joined to the reinforcing bar joints 50 of the middle precast concrete member 32 by the reinforcing bar joints 50. Thus, the lower precast concrete member 31 and the middle precast concrete member 32 are firmly joined together. In addition, the middle stage precast concrete member 32 and the upper stage precast concrete member 33 are firmly joined by upper horizontal joint portion 35, similar to the lower stage precast concrete member 31 and the middle stage precast concrete member 32.

[0034] Second Embodiment FIG. 15 is a vertical cross-sectional view of a seismic isolation foundation structure 1A according to the second embodiment. In this embodiment, the structure of a lower seismic isolation base 10A is different from that of the first embodiment. That is, reinforcing bar joints 14 are embedded in the lower surface of lower seismic isolation foundation 10A. Reinforcing bars 15 are embedded inside lower seismic isolation foundation 10A, and these reinforcing bars 15 are joined to the upper ends of reinforcing bar joints 14. Meanwhile, reinforcing bars 7 protrude from the upper surface of floor surface 2. By lifting and placing the lower seismic isolation foundation 10A on the floor surface 2, the reinforcing bars 7 on the floor surface 2 are inserted into the reinforcing bar joints 14 of the lower seismic isolation foundation 10A. In this state, the lower seismic isolation foundation 10 is fixed onto the floor surface 2 by filling the reinforcing bar joints 14 with a filler. According to this embodiment, the same effects as those (1) to (3) described above are obtained.

[0035] The present invention is not limited to the above-described embodiment, and modifications and improvements within the scope of the present invention that can achieve the object of the present invention are included in the present invention. [Explanation of symbols]

[0036] P…Gap 1, 1A…Seismic isolation foundation structure 2…Floor 3…Beam 4…Column 5... Recessed portion provided in floor surface 6... Concrete body 7... Reinforcing bar 10, 10A... Lower seismic isolation foundation 11... Lower base plate 12... Female thread 13...Anchor bolt 14...Reinforcing bar joint 15...Reinforcing bar 20... Seismic isolation device 21... Laminated rubber 22... Lower flange 23... Upper flange 24, 25...Bolt insertion holes 26, 27...Bolts 30…Upper seismic isolation foundation (seismic isolation foundation part) 31...Lower precast concrete member (lower precast concrete member) 32...Middle precast concrete member (lower precast concrete member, upper precast concrete member) 33...Upper precast concrete member (upper precast concrete member) 34...Lower horizontal joint part 34A...Preliminary filling part 34B...Later filling part 35...Upper horizontal joint section 35A...Pre-fill section 35B...Post-fill section 36...Injection hole 37...Drain hole 38...Injection hole 39...Drain hole 40: Upper base plate; 41: Female thread portion; 42: Anchor bolt 43...Reinforcing bar 44...Lower beam main bar 50...Reinforcing bar joint 51...Reinforcing bar joint 52...Reinforcing bar 60...Reinforcing bar 61...Upper beam main bar 62...Column main bar 70... Female thread portion 71... Support plate 72... Bolt 75...Outer perimeter formwork (preceding formwork) 76...Air formwork (preceding formwork) 77...Outer perimeter formwork (post-construction formwork) 80: Anti-floating metal fitting 81: Lower metal fitting 82: Upper metal fitting 83: Connecting member

Claims

1. A seismic isolation foundation structure including a plurality of seismic isolation devices and a reinforced concrete seismic isolation foundation portion provided on the plurality of seismic isolation devices, The seismic isolation base portion includes a lower precast concrete member, an upper precast concrete member placed on the lower precast concrete member, and a horizontal joint portion formed by filling a filler between the lower precast concrete member and the upper precast concrete member, A seismic isolation foundation structure, characterized in that the multiple seismic isolation devices and the seismic isolation foundation portion are joined via anchor bolts.

2. A method for constructing a seismic isolation foundation structure by joining a plurality of seismic isolation devices and a reinforced concrete seismic isolation foundation portion provided on the plurality of seismic isolation devices, comprising the steps of: The seismic isolation base portion is formed by stacking a lower precast concrete member, a horizontal joint portion, and an upper precast concrete member in this order from the bottom, installing the plurality of seismic isolation devices; placing the lower precast concrete member on the plurality of seismic isolation devices and fastening the seismic isolation devices and the lower precast concrete member with bolts; placing the upper precast concrete member on the lower precast concrete member with a predetermined gap therebetween; and a step of forming a horizontal joint by pressing a filler into the gap between the lower precast concrete member and the upper precast concrete member. The step of forming the horizontal joint includes a step of erecting a preliminary formwork surrounding a predetermined range of the gap between the lower precast concrete member and the upper precast concrete member; A step of forming a pre-filled portion by injecting a filler material into an area surrounded by the pre-form through an injection hole provided inside the upper precast concrete member; After the filling material has hardened, the preliminary formwork is removed and the remaining area of ​​the gap is surrounded by a post-construction formwork; and a step of completing the horizontal joint portion by injecting filler material into the area surrounded by the post-installed formwork to form a post-installed filling portion.

3. The injection hole extends from a side surface of the upper precast concrete member to a center of each of the advance filling portion and the post-construction filling portion of the upper precast concrete member, The lower precast concrete member is provided with a reinforcing bar protruding upward, The method for constructing a seismic isolation foundation structure as described in claim 2, characterized in that a reinforcing bar joint into which a reinforcing bar protruding from the lower precast concrete member is inserted is embedded in the upper precast concrete member, and a discharge hole is provided from the reinforcing bar joint to the side of the upper precast concrete member.

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