JP2020002580A - Aseismic upper foundation structure and construction method thereof, and installation method of aseismic foundation - Google Patents

Abstract

To provide an aseismic upper foundation structure constructed using precast concrete.SOLUTION: An aseismic upper foundation structure comprises a base plate provided with through holes, a concrete part on the base plate, base bars installed in the concrete part, closed end nuts of which upper part fixed on the base plates aligned with the through holes are exposed from the concrete parts, and an anchor plate arranged at upper ends of the closed end nuts. The concrete part comprises a flat plate part exposing an upper part of the closed end nut and a raised part surrounding the flat plate part.SELECTED DRAWING: Figure 1

Description

  One embodiment of the present invention relates to a foundation structure provided on a seismic isolation device. One embodiment of the present invention relates to a method for manufacturing a base structure provided on a seismic isolation device. Further, one embodiment of the present invention relates to a method for constructing a base-isolated foundation using a base-isolated upper substructure manufactured by a precast concrete (PCa) method.

  In order to enhance the seismic resistance of buildings such as buildings, a base-isolated structure is provided at the foundation. As a seismic isolation structure, for example, a structure in which a precast concrete board (PCa board) is arranged on a seismic isolation apparatus provided on a lower foundation and fixed by an anchor member (see Patent Document 1), A structure in which a precast concrete plate provided with a fixing portion for fixing a reinforcing bar is provided on the upper side (see Patent Document 2), and a precast concrete plate in which a reinforcing bar for fixing a main leg is embedded is placed on a seismic isolation device. The disclosed structure (see Patent Document 3) is disclosed.

JP 2012-067524 A (Patent No. 57377554) JP 2014-09943 A (Patent No. 5345238) JP 2011-047201 A (Patent No. 5232106)

  In order to form a foundation called a footing on the seismic isolation device, it is necessary to cast concrete on site. In order to cast concrete, it is necessary to install a formwork and support it with formwork supports. Since a large amount of concrete is cast to form the foundation structure, a large amount of formwork support is also required. Therefore, there is a problem that construction on site becomes complicated. In addition, there is a problem that the work of arranging the reinforcing bars becomes complicated when the reinforcing bars for the footing and the reinforcing bars for the foundation beams of the building are mixed. In addition, when a base-isolated foundation structure made of precast concrete is used, it is required to improve seismic resistance.

  An object of the present invention is to provide a seismic isolation upper substructure for solving such a problem.

  The seismic isolation upper substructure according to an embodiment of the present invention includes a base plate having a through hole, a concrete portion on the base plate, a base bar embedded in the concrete portion, and an upper portion fixed to the base plate in accordance with the through hole. Has a bag-shaped nut exposed from the concrete portion, and a fixing plate provided at an upper end of the bag-shaped nut. The concrete part has a flat part exposing the upper part of the bag-like nut and a rising part surrounding the flat part.

  The method for manufacturing the seismic isolation upper substructure according to one embodiment of the present invention includes disposing, on a base plate having a through-hole formed therein, a bag-shaped nut having a fixing plate attached thereto in accordance with the arrangement of the through-hole, Arrange the base streaks inside the outer formwork, arrange the outer formwork standing upright on the base plate and the inner formwork provided in a state of being floated from the base plate inside the outer formwork, and inside the outer formwork The concrete part is cast at a height reaching the lower end of the inner formwork, and the concrete part is cast between the outer formwork and the inner formwork, so that the upper part of the bag-shaped nut is exposed. And forming a rising portion surrounding the rising edge.

  A method for manufacturing a seismic isolation upper substructure according to one embodiment of the present invention includes installing the seismic isolation upper substructure manufactured by the precast concrete (PCa) method according to one embodiment of the present invention on a seismic isolation device. Then, arranging the beam main reinforcement of the foundation beam on the seismic isolation upper substructure, burying the upper part of the bag-like nut, and casting concrete so that the rising part is fitted.

  The seismic isolation upper foundation structure according to one embodiment of the present invention is constructed such that the concrete portion in which the base reinforcement is embedded has a flat plate portion and a rising portion, and the bag-shaped nut and the fixing plate are exposed from the flat plate portion. When used as the basis of an object, it can exhibit high resistance to pitching and rolling.

  ADVANTAGE OF THE INVENTION According to the manufacturing method which concerns on one Embodiment of this invention, when casting concrete at a work site in order to manufacture a seismic-isolation upper substructure, it is not necessary to install a formwork and a formwork support. In addition, complicated work can be reduced. In addition, since it is possible to prevent the reinforcement for the seismic isolation upper foundation structure and the reinforcement for the foundation beam from being mixed, the work of arranging the reinforcement can be simplified.

  ADVANTAGE OF THE INVENTION According to the construction method of the base-isolated foundation which concerns on one Embodiment of this invention, a foundation beam can be formed closely on the base-isolated upper substructure made from precast concrete (PCa), and the construction is simplified. And the seismic resistance of the foundation beam can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS The seismic isolation upper foundation structure which concerns on one Embodiment of this invention is shown, (A) is a top view and (B) is a schematic cross section. FIG. 2A is a perspective view showing a partial structure of a seismic isolation upper foundation according to an embodiment of the present invention, FIG. 2A is a perspective view showing an arrangement of a bag-like nut on a base plate, and FIG. FIG. 1 shows a schematic cross-sectional view of a seismic isolation upper substructure according to an embodiment of the present invention. It is sectional drawing which shows the detail of the rising part of the seismic isolation upper foundation structure which concerns on one Embodiment of this invention. It is a sectional view showing the state where the seismic isolation upper foundation structure concerning one embodiment of the present invention was attached to the seismic isolation device. The top view of the seismic isolation upper foundation structure concerning one embodiment of the present invention is shown, (A) shows a mode in which rise parts were arranged in parallel, and (B) shows a mode in which rise parts were arranged in the crossing direction. . BRIEF DESCRIPTION OF THE DRAWINGS It is a top view which shows one aspect which arranged the seismic isolation upper foundation structure which concerns on one Embodiment of this invention in the seismic isolation base part. It is sectional drawing explaining the manufacturing method of the seismic isolation upper foundation structure which concerns on one Embodiment of this invention, (A) is a stage which arrange | positions a bag-shaped nut on a base plate, (B) is a form around a base plate. The stage of arrangement is shown. It is a top view explaining the manufacturing method of the seismic isolation upper foundation structure concerning one embodiment of the present invention, and shows the mode in which the formwork surrounding a base plate is arranged. It is sectional drawing explaining the manufacturing method of the seismic isolation upper foundation structure which concerns on one Embodiment of this invention, (A) is the stage where concrete is cast to the lower end of an inner frame, (B) is an outer frame and an inner frame. Shows the stage during which concrete is cast. It is sectional drawing explaining the construction method of the base isolation base which concerns on one Embodiment of this invention, and shows the stage which installs a base isolation structure on a base isolation device. It is sectional drawing explaining the construction method of the base isolation base which concerns on one Embodiment of this invention, and shows the stage of arranging a beam main reinforcement on a base isolation upper foundation structure. It is sectional drawing explaining the construction method of the base-isolated foundation which concerns on one Embodiment of this invention, and shows the stage which forms a foundation beam. It is a perspective view showing one mode in which the foundation beam was provided on the seismic isolation upper foundation structure concerning one embodiment of the present invention. It is sectional drawing which shows one aspect which provided the foundation beam on the seismic isolation foundation structure which concerns on one Embodiment of this invention. It is a perspective view showing one mode in which the foundation beam was provided on the seismic isolation upper foundation structure concerning one embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention includes many different aspects and is not to be construed as being limited to the contents of the embodiments exemplified below. In order to make the description clearer, the width, thickness, shape, etc. of each part may be schematically illustrated as compared with the actual embodiment, but this is merely an example, and the content of the present invention is limited. It does not do. Also, in this specification, when an element described in a drawing and an element described in another drawing have the same or corresponding relationship, the same reference numeral (or the numeral (Reference numerals to which a, b, and the like are added later), and the repeated description may be omitted as appropriate. Furthermore, the characters “first” and “second” added to each element are convenient markers used to distinguish each element, and have no further meaning unless otherwise specified. .

1. 1A and 1B show a base structure (hereinafter, referred to as a “seismically isolated upper base structure”) provided on an upper part of a base isolation device according to an embodiment of the present invention. The upper substructure is sometimes referred to as "upper footing." FIG. 1A is a plan view of a seismic isolation upper substructure 100 according to the present embodiment, and FIG. 1B is a schematic diagram of a cross-sectional structure thereof. The seismic isolation upper substructure 100 includes a base plate 102, a base streak 116, a concrete portion 106, a bag-shaped nut 112, and a fixing plate 114 provided on the top of the bag-shaped nut 112.

  The base plate 102 has a plurality of through holes 104. The through hole 104 in the base plate 102 is arranged in accordance with the through hole for inserting an anchor bolt formed in the upper flange of the seismic isolation device. For example, the through holes 104 are arranged at a plurality of positions on a circumference having a predetermined radius with the center of the base plate 102 as a center of gravity. The base plate 102 is made of metal, and is made of, for example, steel. The thickness of the base plate 102 is arbitrary, but has a thickness of 10 mm to 30 mm, for example, 20 mm. Although FIG. 1A shows a case where the base plate 102 is rectangular, the planar shape of the base plate 102 is not limited to this and may be another polygon or a circle.

  On the base plate 102, a bag-like nut 112 is arranged in accordance with the arrangement of the through holes 104. A fixing plate 114 is provided above the bag-shaped nut 112. The fixing plate 114 protrudes from the main body of the bag-shaped nut 112. As shown in FIG. 2A, the bag-shaped nut 112 is provided upright on the upper surface of the base plate 102 so that the anchor bolt inserted into the through hole 104 is screwed. As shown in FIG. 2B, the through hole 104 of the base plate 102 and the screw hole of the cap nut 112 are arranged so that they are aligned. The position of the cap nut 112 is fixed by being partially embedded in the concrete portion 106 on the base plate 102. In this case, the bag-shaped nut 112 may be fixed to the base plate 102 by welding in advance, as shown in FIG. By fixing the sack-shaped nut 112 on the base plate 102 by welding, it is possible to arrange the nut with high accuracy and to stably hold the seismic isolation upper substructure 100 on the seismic isolation device.

  As shown in FIGS. 1A and 1B, the concrete part 106 is provided on the upper surface of the base plate 102. In addition, as shown in FIG. 3, the concrete portion 106 may be provided so as to cover the upper surface and the side surface of the base plate 102. By burying the upper surface and side surfaces of the base plate 102 in the concrete portion 106, the bottom surface of the seismic isolation upper substructure 100 can be flattened, and the shearing force acting between the base plate 102 and the concrete portion 106 Resistance can be increased.

  The concrete part 106 has a flat part 108 parallel to the base plate 102 and a rising part 110 protruding from the flat part 108. The rising portions 110 are provided so as to surround four sides of the flat plate portion 108 along the periphery of the concrete portion 106. Although the flat plate portion 108 and the rising portion 110 are described as different portions for convenience of description, they are inseparable from each other so as to form one structure as the concrete portion 106.

  The base bar 116 is provided so as to be embedded in the concrete portion 106. A plurality of base bars 116 are arranged in the concrete portion 106. The thickness (cover thickness) from the surface of the concrete portion 106 to the base streaks 116 is arbitrary, and has a thickness of, for example, 40 mm to 60 mm. The plurality of base streaks 116 are provided in the concrete portion 106 so as to intersect vertically and horizontally so as not to interfere with the cap nut 112. The plurality of base streaks 116 are bound by a binding wire at the intersection. As shown in FIG. 1B, the plurality of base bars 116 have a shape that is bent at the rising portion 110 of the concrete portion 106 so as to protrude upward. In other words, the plurality of base streaks 116 are arranged in a lattice pattern in the flat plate portion 108 and are provided so as to protrude from the upper surface of the rising portion 110, thereby having a cage shape with an open top. . The portion where the base bar 116 projects from the concrete portion 106 is also called a footing cage bar 118. As shown in FIG. 1B, the tip of the footing cage bar 118 may be bent in a U-shape.

  The concrete portion 106 is bent such that the base streaks protrude upward, so that the strength and durability of the rising portion 110 are enhanced. Although not shown in the drawings, the concrete portion 106 may be provided with a frame-shaped base streak along the rising portion 110. The height of the rising portion 110 is provided to be higher than the heights of the bag-shaped nut 112 and the fixing plate 114 as described later. Further, the thickness of the rising portion 110 is appropriately set, but has a width that at least satisfies the covering thickness of the footing cage bar 118.

  The cap nut 112 is provided such that the lower portion is embedded in the concrete portion 106 and the upper portion is exposed from the concrete portion 106. As shown in FIG. 4, the bag-shaped nut 112 is arranged on the flat plate portion 108 of the concrete portion 106. The upper portion of the bag-shaped nut 112 and the fixing plate 114 are arranged so as to be exposed from the flat plate portion 108 and surrounded by the rising portion 110. The length L of the cap nut 112 is larger than the thickness D of the flat plate 108, and at least the fixing plate 114 is provided so as to be exposed from the flat plate 108. On the other hand, the height h2 at which the bag-shaped nut 112 and the fixing plate 114 protrude from the upper surface of the flat plate portion 108 is provided so as to be smaller than the height h1 at which the rising portion 110 protrudes from the upper surface of the flat plate portion 108. That is, the height h1 of the rising portion 110 and the height h2 of the bag-shaped nut are provided such that a relationship of h1> h2 holds.

  A footing 131 and a foundation beam 132 are provided on the seismic isolation upper substructure 100. When the foundation beam 132 is made of reinforced concrete, reinforcing bars are arranged on the concrete portion 106. In this case, a spacer 143 supporting the beam main reinforcement 134 is disposed on the upper surface of the rising portion 110 in order to secure the cover thickness of the concrete.

  In the seismic isolation upper substructure 100, the cap nut 112 and the fixing plate 114 are provided so as not to protrude from the rising portion 110, so that the cap nut 112 does not interfere when the beam main reinforcement 134 is arranged. be able to. Since the concrete portion 106 has the rising portion 110, the main beam 134 can be held at a position away from the flat plate portion 108. Since the rising portion 110 has a certain height, the spacer 143 only needs to have a height sufficient to secure the cover thickness of the concrete, and the spacer 143 can be downsized compared to the related art. . Thus, the rising portion 110 can be used as a support for the beam main reinforcement 134. When arranging the foundation beams 132 on the seismic isolation upper substructure 100, the arrangement of the reinforcements can be facilitated by using the rising portions 110 as the supporting portions of the beam main reinforcements 134.

  In the present embodiment, it is preferable that the concrete portion 106 is not made by directly casting concrete on the seismic isolation device, but is made of precast. Since the seismic isolation upper substructure 100 is made of precast concrete, the work of arranging the formwork and curing the work site at the work site forming the foundation of the building is omitted, and the work efficiency is improved. Can be improved.

  FIG. 5 is a cross-sectional view showing a state in which the seismic isolation upper substructure 100 is attached to the seismic isolation device 122. The seismic isolation upper substructure 100 is fixed to the seismic isolation device 122 by anchor bolts 130. The seismic isolation device 122 includes a seismic isolation rubber part 124, an upper flange 126, and a lower flange 128. The anchor bolt 130 is inserted into the through hole 104 of the base plate 102 from the upper flange 126 of the seismic isolation device 122 and screwed to the cap nut 112. The seismic isolation upper substructure 100 is stably held on the seismic isolation device 122 by fastening a plurality of locations with the anchor bolts 130. In addition, the seismic isolation device 122 is fixed on the seismic isolation lower substructure 120 by an anchor bolt 130 that penetrates the lower flange 128.

  A footing 131 and a foundation beam 132 are provided on the seismic isolation upper substructure 100. The footing 131 and the foundation beam 132 are produced by casting concrete so as to bury a beam main reinforcing bar (not shown in FIG. 5). The concrete forming the footing 131 and the foundation beam 132 is provided so as to be in close contact with the upper surface of the seismic isolation upper substructure 100. That is, the concrete forming the footing 131 and the foundation beam 132 is provided so as to be in close contact with the rising portion 110 of the seismic isolation upper substructure 100 and the upper surface of the flat plate portion 108. Thus, the concrete forming the footing 131 and the foundation beam 132 is filled in the concave region formed by the flat plate portion 108 and the rising portion 110 of the concrete portion 106. The footing cage 118 protruding from the rising portion 110 extends into the footing 131, thereby increasing the joint strength between the seismic isolation upper substructure 100 and the footing 131 and the foundation beam 132.

  The seismic isolation upper substructure 100 and the foundation beam 132 are joined such that both are formed of concrete and the footing cage bar 118 projects to a part of the footing 131. The rising portion 110 of the seismic isolation upper substructure 100 serves as a site where a reaction occurs when a lateral force is applied to the foundation beam 132, and generates resistance against lateral sliding of the foundation beam 132. Assuming that there is no rising portion, when a lateral force is applied to the foundation beam, the shear force generated between the base beam and the seismic isolation upper substructure directly acts on the boundary portion. On the other hand, in the seismic isolation upper substructure 100 according to the present embodiment, since the rising portion 110 is erected in a direction intersecting the direction in which the shear force acts, it is generated by the lateral swing of the foundation beam 132. The applied shearing force can be prevented from directly acting on the boundary between the base isolation structure 100 and the footing 131 or the foundation beam 132. Thereby, the seismic isolation upper substructure 100 can enhance the resistance of the building to the roll of the earthquake.

  In the seismic isolation upper substructure 100, the bag-shaped nut 112 and the fixing plate 114 protruding from the flat plate portion 108 are embedded in the footing 131. Since the fixing plate 114 is provided so as to protrude from the main body of the bag-shaped nut 112, the fixing plate 114 is a portion that generates a resistance against a vertical force acting on the footing 131 and the foundation beam 132. That is, the seismic isolation upper substructure 100 is provided in such a manner that the fixing plate 114 provided above the bag-shaped nut 112 protrudes from the flat plate portion 108 and is buried in the footing 131, so that the vertical vibration and vibration It is possible to increase the resistance to.

  Although FIG. 1A shows a structure in which the rising portions 110 surround four sides of the flat plate portion 108, the seismic isolation upper foundation structure 100 according to the present embodiment is not limited to this. For example, as shown in FIG. 6A, the rising portion 110 may be provided so as to surround three sides (or three directions) at a peripheral portion of the flat plate portion 108 (see FIG. 6A). Rising portions 110a, 110b, 110c). Further, as shown in FIG. 6B, the rising portion 110 may be provided at the peripheral portion of the flat plate portion 108 so as to extend in two intersecting directions (see the rising portion shown in FIG. 6B). Parts 110d, 110e).

  FIG. 7 shows an example in which the seismic isolation upper substructure 100 having a different configuration of the rising portion 110 is appropriately arranged on the seismic isolation base portion. FIG. 7 shows a plurality of types of seismic isolation upper substructures 100a, 100b, and 100c that support the foundation beams 132 that are arranged in a grid pattern with reinforced concrete. As shown in FIG. 1 (A), the seismic isolation upper substructure 100a has a structure in which rising portions are provided so as to surround four sides of the flat plate portion. As shown in FIG. 6, the rising portion has a U-shape surrounding three sides, and the base-isolated upper substructure 100c extends along two sides where the rising portions intersect as shown in FIG. It has an L-shaped (or hook-shaped) shape provided. FIG. 7 shows that the U-shaped rising portion of the base-isolated base structure 100b is disposed so as to face the outside of the beam 135a extending in the X direction and the column 135b extending in the Y direction. The aspect in which the rising portions are arranged so as to face outward at the four corners of the beams 135a and 135b is shown. As shown in FIG. 7, by arranging the seismic isolation upper substructures 100 a, 100 b, and 100 c having different configurations of the rising portions, the seismic resistance of the foundation beams can be enhanced.

2. 1. Manufacturing Method of Seismic Isolation Upper Substructure The manufacturing method of the base isolation upper structure 100 shown in FIG. 1 will be described with reference to FIGS. The seismic isolation upper substructure 100 according to the present embodiment is manufactured by a precast concrete (PCa) method. Hereinafter, a manufacturing method based on the precast concrete (PCa) method will be described.

  FIG. 8A shows a step of disposing a bag-like nut 112 having a fixing plate 114 on the upper surface of the base plate 102 in which the through hole 104 is formed. The base plate 102 may be supported on a base 136. The cap nut 112 is arranged in accordance with the position of the through hole 104. The cap nut 112 may be temporarily fixed by a mounting bolt inserted from the lower surface of the base plate 102 into the through hole 104, or may be fixed to the base plate 102 by welding as shown in FIG. Good.

  As shown in the cross-sectional view of FIG. 8B and the plan view of FIG. 9, a mold 138 is arranged so as to surround the base plate 102. Specifically, an outer mold 138a surrounding the base plate 102 and an inner mold 138b arranged at a predetermined interval inside the outer mold 138a are arranged. The outer formwork 138a may include a lower formwork portion whose height is substantially the same as the upper surface of the base plate 102. The inner formwork 138b is supported in a state of floating from the base plate 102 to form the rising portion 110. The height of the lower end of the inner mold 138b is arranged to be lower than the heights of the bag nut 112 and the fixing plate 114. The outer form 138a is supported by the base 136, and the inner form 138b is supported by the inner form fixing fastener 140. The outer formwork 138a may be supported by a formwork support (not shown) so that the arrangement is stable. The outer formwork 138a and the inner formwork 138b are made of metal or wood, and as the fastener 140 for fixing the inner formwork, for example, a bolt and a nut are used.

  The procedure for arranging the bag-shaped nut 112, the arrangement of the base streaks 116, and the arrangement of the outer mold 138a and the inner mold 138b is not limited to the above, and may be changed as appropriate. If the structure shown in FIG. 8B is completed before the concrete is cast, the order in which the members are installed may be changed.

  FIG. 10A shows a step of arranging the base bar 116 inside the formwork 138 and casting concrete to the lower end of the inner formwork 138b or its vicinity to form the flat plate portion 108. As shown in FIG. 1A, the base streaks 116 are arranged in a lattice shape in the outer formwork 138a. The base streaks 116 are arranged such that a portion corresponding to the footing cage streaks 118 extends upward from between the outer formwork 138a and the inner formwork 138b. The concrete is buried so that the base streaks 116 are embedded and the upper portion of the bag-like nut 112 and the fixing plate 114 are exposed. The concrete poured in at this stage hardens, so that the bag-shaped nut 112 is securely fixed on the base plate 102.

  FIG. 10 (B) shows a step of placing concrete between the outer formwork 138a and the inner formwork 138b. The operation of pouring concrete between the outer formwork 138a and the inner formwork 138b is preferably performed in a state where the concrete forming the flat plate portion 108 is stabilized and hardened to some extent. The rising portion 110 is formed by concrete cast between the outer formwork 138a and the inner formwork 138b. The height of the rising portion 110 can be adjusted by the amount of concrete poured between the outer formwork 138a and the inner formwork 138b. In this case, the amount of concrete poured between the outer mold 138a and the inner mold 138b is desirably an amount sufficient to at least be higher than the height of the fixing plate 114 protruding from the flat plate portion 108.

  After the concrete has hardened, the outer formwork 138a and the inner formwork 138b are removed. By such a precast concrete (PCa) method, a seismic isolation upper substructure 100 as shown in FIGS. 1A and 1B is manufactured. As shown in this embodiment, the seismic isolation upper substructure 100 having the rising portions 110 can be manufactured by placing the precast concrete in two stages.

  According to the manufacturing method according to the present embodiment, since it is not necessary to cast concrete at the work site to manufacture the seismic isolation upper substructure, there is no need to perform the work of installing the formwork and the formwork support, Complicated work can be reduced. In addition, since it is possible to prevent the reinforcement for the seismic isolation upper foundation structure and the reinforcement for the foundation beam from being mixed, the work of arranging the reinforcement can be simplified.

  Furthermore, since the seismic isolation upper substructure according to the present embodiment can be individually manufactured in a factory or a work place instead of being manufactured directly above the seismic isolation device, quality control of concrete is easy, and This has the advantage that the variation in can be reduced. This makes it possible to reduce the thickness (cover thickness) of the concrete, so that the load on the seismic isolation upper substructure 100 can be reduced and the size can be reduced. Further, when the seismic isolation upper substructure 100 is manufactured in a factory, it can be produced systematically without being affected by the weather or the like, so that the construction period can be shortened. Furthermore, compared to the method of placing concrete on site, the amount of use of the formwork and formwork support can be reduced, complicated work can be omitted on site, and construction costs can be reduced. In the present embodiment, as shown in FIGS. 10A and 10B, a mode in which concrete is cast in two stages is shown, but the present invention is not limited to this. 108 and the rising portion 110 may be formed.

3. Construction Method of Seismic Isolation Foundation A construction method of a seismic isolation foundation using the seismic isolation upper foundation structure according to one embodiment of the present invention will be described with reference to FIGS.

  The seismic isolation upper substructure 100 manufactured by the precast concrete (PCa) method is transported to the installation site of the construction site where the foundation work is performed. As shown in FIG. 11, the seismic isolation device 122 is in a state of being installed on the seismic isolation lower foundation structure 120. The seismic isolation upper substructure 100 is installed on the upper flange 126 of the seismic isolation device 122 and fixed by anchor bolts 130.

  Thereafter, as shown in FIG. 12, an operation of arranging a beam main reinforcing bar and the like for forming a foundation beam is performed on the seismic isolation upper substructure 100. The beam main reinforcements 134a, 134b, 134c, 134d are respectively arranged in the longitudinal direction of the foundation beam. At this time, the rising part 110 of the seismic isolation upper substructure 100 is used as a part supporting the beam main reinforcement 134d. Further, around the beam main reinforcements 134a, 134b, 134c, 134d, a shear reinforcement (also referred to as a hoop) 142 is appropriately arranged. The beam main reinforcements 134a, 134b, 134c, 134d and the shear reinforcement 142 are appropriately bound by a binding line.

  FIG. 13 shows the step of casting concrete to produce the footing 131 and the foundation beam 132. The beam main reinforcements 134a and 134b are supported by the spacers 143 in a state of being floated from the upper surface of the rising portion 110 of the seismic isolation upper substructure 100. A formwork (not shown) and a formwork support are installed so as to surround the beam main reinforcements 134a and 134b and the shear reinforcement 142, and concrete is cast. Concrete is also cast on the upper surface side of the seismic isolation upper substructure 100. The concrete is also filled in the concave area formed by the rising part 110 and the flat part 108 of the base isolation structure 100. As a result, the bag nut 112 and the fixing plate 114 are embedded in the concrete. Further, at a portion where the foundation beam 132 and the seismic isolation upper substructure 100 intersect, the rising part 110 is formed so as to be located at the lower end of the concrete of the foundation beam 132. After curing the concrete for the foundation beam, the formwork (not shown) is removed to form the foundation beam 132.

  FIG. 14 is a perspective view showing a state in which the seismic isolation upper substructure 100 is attached to the seismic isolation device 122, and further, a footing 131 and a foundation beam 132 made of reinforced concrete are formed. A footing 131 is provided on an upper part of the seismic isolation upper substructure 100, and a foundation beam 132 is extended in a horizontal direction so as to connect adjacent footings 131. Although not shown in FIG. 14, a pillar is provided on the footing 131 in a vertical direction.

  FIG. 15 shows an embodiment in which the foundation beam 132 is formed of a steel frame material. Various steel shapes can be used as the steel frame material that can be used for the foundation beam 132. FIG. 15 shows an embodiment in which an H-shaped steel is used for the foundation beam 132. In this case, a steel frame material used as the foundation beam 132 is directly disposed on the upper surface of the rising portion 110 of the seismic isolation upper substructure 100. Since the seismic isolation upper substructure 100 has the rising portion 110, it can be arranged so as not to interfere with the bag-like nut 112 and the fixing plate 114. Concrete is cast on the seismic isolation upper substructure 100, and the footing 131 is formed.

  FIG. 16 is a perspective view showing a state in which the seismic isolation upper substructure 100 is attached to the seismic isolation device 122, and further, a footing 131 and a foundation beam 132 formed of a steel frame material are formed. A footing 131 is provided on the upper part of the seismic isolation upper substructure 100, and a foundation beam 132 is provided so as to connect adjacent footings 131. Although not shown in FIG. 16, a pillar is provided on the footing 131 in a vertical direction.

  According to the method for constructing a seismic isolation foundation according to the present embodiment, it is possible to form the foundation beam 132 closely on the seismic isolation upper substructure 100 made of precast concrete (PCa). In addition, since the bag-shaped nut 112 and the fixing plate 114 exposed from the flat plate portion 108 are buried in the concrete of the foundation beam 132, they can exhibit high resistance to vertical vibration. As described above, according to the method for constructing a seismic isolation foundation according to the present embodiment, a foundation structure with high earthquake resistance can be formed.

  In the present embodiment, an example in which the seismic isolation upper substructure 100 is manufactured by a precast concrete (PCa) method is shown, but the present invention is not limited to this.

100 ... seismic isolation upper foundation structure, 102 ... base plate, 104 ... through hole, 106 ... concrete part, 108 ... flat plate part, 110 ... rising part, 112 ... bag shape Nut, 114: fixing plate, 116: base bar, 118: footing cage bar, 120: base structure of seismic isolation, 122: seismic isolation device, 124: rubber part of seismic isolation , 126 ... upper flange, 128 ... lower flange, 130 ... anchor bolt, 131 ... footing, 132 ... foundation beam, 134 ... beam reinforcement, 136 ... base, 138 ..Forms, 140 ... Inner form fixing fasteners, 142 ... Shear reinforcement, 143 ... Spacers

Claims (16)

A base plate having a through hole,
A concrete part on the base plate,
A base bar buried in the concrete portion,
A bag-shaped nut fixed to the base plate in accordance with the through-hole and having an upper part exposed from the concrete part,
A fixing plate provided at an upper end of the bag-shaped nut,
Has,
The said concrete part has the flat part in which the said bag-shaped nut is arrange | positioned, and the rising part which surrounds the said flat part, The seismic isolation upper foundation structure characterized by the above-mentioned.   The base-isolated upper substructure according to claim 1, wherein the rising portion surrounds the periphery of the flat plate portion.   The seismic isolation upper substructure according to claim 1, wherein the rising portion surrounds the bag-shaped nut and the flat plate portion.   The base-isolated upper substructure according to claim 1, wherein the rising portion is provided at a peripheral portion of the concrete portion.   The seismic isolation upper substructure according to any one of claims 1 to 4, wherein the concrete part is a precast concrete part.   The seismic isolation upper substructure according to any one of claims 1 to 5, wherein a footing cage bar protrudes upward from an upper surface of the rising portion.   The seismic isolation upper substructure according to claim 1, wherein a height of the rising portion is higher than a height of the fixing plate.   The seismic isolation upper substructure according to any one of claims 1 to 7, wherein the bag-shaped nut is welded to the base plate.   The seismic isolation upper substructure according to any one of claims 1 to 8, wherein the base plate is embedded in the concrete part. On the base plate on which the through-hole is formed, in accordance with the arrangement of the through-hole, dispose a bag-shaped nut with a fixing plate attached to the upper part,
An outer formwork that stands upright with respect to the base plate, and an inner formwork provided inside the outer formwork while being floated from the base plate,
Arrange a base bar inside the outer formwork,
By casting concrete inside the outer mold to a height reaching the lower end of the inner mold, and casting concrete between the outer mold and the inner mold, the bag-shaped nut is formed. Forming a flat portion exposing the upper portion of the flat portion, and a rising portion surrounding the flat portion.   The concrete is poured into the inside of the outside form to a height reaching a lower end of the inside form, and after hardening, concrete is poured between the outside form and the inside form. 11. The method for manufacturing a seismic isolation upper substructure according to 10. The height of the lower end of the inner mold is arranged lower than the height of the fixing plate of the bag-shaped nut,
12. The seismic isolation device according to claim 10, wherein a height of concrete cast between the outer mold and the inner mold is higher than a height of a fixing plate of the bag-shaped nut. 13. How to make the upper substructure.   The method for producing a base-isolated upper substructure according to any one of claims 10 to 12, wherein the concrete is cast by a precast concrete method.   The method for producing a base-isolated upper substructure according to any one of claims 10 to 13, wherein the bag-shaped nut is fixed to the base plate by welding.   The method for producing a base-isolated upper substructure according to any one of claims 10 to 14, wherein concrete is cast so as to cover an upper surface and side surfaces of the base plate. The seismic isolation upper substructure according to any one of claims 10 to 15 is installed on a seismic isolation device,
Arranging a beam main reinforcement of a foundation beam on the seismic isolation upper foundation structure, burying an upper portion of the bag-like nut, and casting concrete so that the rising portion is fitted therein. Construction method.

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