Base-isolation structure and construction method thereof

Abstract

To accurately and horizontally install a base isolation device while suppressing the height of a base isolation structure.SOLUTION: A base isolation structure construction method comprises a foundation skeleton construction step of constructing a foundation skeleton 12 in which an anchor bolt 25 and a long nut 27 screwed to the tip of the anchor bolt 25 is embedded, and a base isolation device installation step of placing a base isolation device 13 on the foundation skeleton 12 constructed in the foundation skeleton construction step and screwing a bolt 15 to the long nut 27 to fix the base isolation device 13 to the foundation skeleton 12.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a seismic isolation structure and a method for constructing the same. [Background technology]

[0002] Patent Document 1 discloses a method for constructing a seismic isolation foundation structure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-003499 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the construction method of Patent Document 1, the lower base plate of the seismic isolation device is fixed to the anchor member, and then the foundation concrete is poured. After the foundation concrete is constructed, it is necessary to construct the lower foundation structure to install the seismic isolation device, which increases the height of the seismic isolation layer and requires the lower foundation structure construction process. The present invention aims to solve such problems, for example. [Means for solving the problem]

[0005] The method for constructing a seismic isolation structure includes a foundation structure construction process for constructing a foundation structure into which anchor bolts and long nuts screwed onto the ends of the anchor bolts are embedded, and a seismic isolation device installation process for placing a seismic isolation device on the foundation structure constructed in the foundation structure construction process and fixing the seismic isolation device to the foundation structure by screwing a bolt into the long nut. The seismic isolation structure includes a foundation structure, an anchor bolt embedded in the foundation structure, a long nut embedded in the foundation structure and screwed onto the tip of the anchor bolt, a seismic isolation device installed on the foundation structure, and a bolt that fixes the seismic isolation device to the foundation structure by screwing it into the long nut. Effect of the Invention

[0006] Since the seismic isolation device is fixed in place after the foundation frame is constructed, the seismic isolation device can be installed accurately without having to construct a lower foundation structure for installation of the seismic isolation device. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a side cross-sectional view showing an example of a seismic isolation structure. [Diagram 2] FIG. 11 is a flow diagram showing an example of a seismic isolation structure construction process. [Diagram 3] FIG. 11 is a flow chart showing an example of a foundation structure construction process. [Figure 4] FIG. [Diagram 5] FIG. 11 is a side cross-sectional view showing an example of an excavation process. [Figure 6] FIG. 11 is a plan view showing an example of an anchor frame installation process. [Figure 7] FIG. 11 is a side cross-sectional view showing an example of an anchor frame installation process. [Figure 8] FIG. 11 is a plan view showing an example of an anchor bolt fixing step. [Figure 9] FIG. 11 is a side cross-sectional view showing an example of an anchor bolt fixing step. [Figure 10] FIG. [Figure 11] FIG. 11 is a side cross-sectional view showing an example of a reinforcing bar arrangement process. [Figure 12] FIG. 4 is a flow diagram showing an example of a seismic isolation device installation process. [Figure 13] FIG. 4 is a side view showing an example of a base mortar installation step. [Figure 14] FIG. 4 is a side view showing an example of a seismic isolation device temporary placement process. [Figure 15] FIG. [Figure 16] FIG. 4 is a side view showing an example of a grout filling step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The seismic isolation structure 10 will be described with reference to FIG. The seismic isolation structure 10 is a structure that is provided in the foundation of a building or the like and prevents vibrations caused by an earthquake or the like from being transmitted to the building. The seismic isolation structure 10 has, for example, a foundation frame 12 and a seismic isolation device 13.

[0009] The foundation framework 12 is made of, for example, reinforced concrete, and is provided in the ground 90 and fixed to the supporting soil. The foundation framework 12 includes, for example, piles 21, a foundation body 22, and a slab 23. The pile 21 extends in the substantially vertical direction (-Z direction) in the ground 90 and reaches the supporting ground. The foundation body 22 has, for example, foundation beams and foundation columns. The slab 23 is provided on top of the foundation body 22 (in the +Z direction).

[0010] The seismic isolation device 13 is fixed to the top (+Z direction) of the foundation frame 12 by bolts 15 or the like, and supports the building body (not shown). By being interposed between the foundation frame 12 and the building body, when the foundation frame 12 vibrates due to an earthquake or the like, the seismic isolation device 13 prevents the vibration from being transmitted to the building body. A grout 16 is provided between the foundation body 12 and the seismic isolation device 13. The grout 16 is, for example, a non-shrink grout, and supports the seismic isolation device 13 horizontally.

[0011] An anchor frame 24, anchor bolts 25, fixing plates 26, long nuts 27, reinforcing bars 28, etc. are embedded in the foundation body 12.

[0012] The anchor frame 24 holds the anchor bolts 25 in place. The anchor frame 24 is a frame formed by combining multiple L-shaped steel bars, for example as shown in Figures 6 and 7, and is installed in a footing recess 92 provided for the foundation column of the foundation body 12.

[0013] The anchor bolts 25 transmit stress from the seismic isolation device 13 to the foundation body 22. As shown in Figures 8 and 9, for example, the anchor bolts 25 extend in a substantially vertical direction (±Z direction) and are arranged at substantially equal intervals in the circumferential direction around a central axis that also extends in a substantially vertical direction. The lower ends (ends on the -Z side) of the anchor bolts 25 are fixed to the anchor frame 24. The length of the anchor bolts 25 (length along the ±Z directions) is longer than the height of the anchor frame 24 (length along the ±Z directions). The fixing plate 26 fixes the anchor bolt 25 to the foundation body 22. The fixing plate 26 is attached near the lower end of the anchor bolt 25, for example, as shown in Figs. The long nut 27 joins the seismic isolation device 13 to the anchor bolt 25. The long nut 27 is screwed onto the upper end (the end on the +Z side) of the anchor bolt 25 and fixed, for example, as shown in Figs. 8 and 9 .

[0014] 10 and 11, the reinforcing bars 28 are arranged in a column shape so as to surround the anchor bolts 25. The reinforcing bars 28 include, for example, a plurality of column reinforcements 81 and a plurality of hoop reinforcements 82. The pillar bars 81 extend in a substantially vertical direction, and the lower end is bent inward in an L-shape. The pillar bars 81 are arranged, for example, in a ring shape around a central axis extending in a substantially vertical direction. For example, four pillar bars 81 are arranged at the four corners of a square, and four pillar bars 81 are arranged at the center of each side of the square. The hoop reinforcement 82 is annular so as to wrap around the entire column reinforcement 81, and is arranged at approximately equal intervals in the approximately vertical direction. By reinforcing the foundation body 22 with the reinforcing bars 28 arranged in a column shape in this manner, the stress transmitted from the seismic isolation device 13 can be reliably transmitted to the foundation body.

[0015] Since the length of the anchor bolt 25 is longer than the height of the anchor frame 24, the lower end of the anchor bolt extends to the lower half of the foundation body 22. Therefore, the anchor bolt 25 is firmly fixed to the reinforcing bars 28 arranged in a column shape. Therefore, it is not necessary to arrange foundation reinforcement or a base plate under the seismic isolation device 13, and the number of work steps can be reduced.

[0016] Next, the seismic isolation structure construction process S10 will be described with reference to FIG. In the seismic isolation structure construction process S10, the seismic isolation structure 10 is constructed. The seismic isolation structure construction process S10 includes, for example, a foundation framework construction step S12 and a seismic isolation device installation step S13. In the foundation framework construction process S12, the foundation framework 12 is constructed. In the seismic isolation device installation step S13, the seismic isolation device 13 is installed on the foundation frame 12 constructed in the foundation frame construction step S12.

[0017] The foundation framework construction step S12 will be described in detail with reference to FIG. The foundation structure construction process S12 includes, for example, an excavation process S21, an anchor frame installation process S22, an anchor bolt fixing process S23, a reinforcing bar arrangement process S24, an anchor frame fixing process S25, a ready-mixed concrete pouring process S26, and a slab formation process S27.

[0018] First, in the excavation process S21, in order to construct the foundation structure 12, the ground 90 is excavated, and, for example, as shown in Figures 4 and 5, underground beam recesses 91 for the foundation beams and footing recesses 92 for the foundation columns are formed, and piles 21 are formed in the ground.

[0019] Next, in the anchor frame installation step S22, for example, as shown in Figs. 6 and 7, the anchor frame 24 is installed in the center of the bottom surface of the footing recess 92 formed in the excavation step S21.

[0020] Thereafter, in an anchor bolt fixing step S23, for example, as shown in Figs. 8 and 9, the anchor bolts 25 are fixed to the anchor frame 24 installed in the anchor frame installation step S22.

[0021] Then, in a reinforcing bar arrangement step S24, for example, as shown in Figs. 10 and 11, reinforcing bars 28 are arranged so as to surround the anchor bolts 25 fixed to the anchor frame 24 in the anchor bolt fixing step S23.

[0022] Next, in the anchor frame fixing step S25, the anchor frame 24 is fixed to the reinforcing bars 28 arranged in the reinforcing bar arrangement step S24, for example, via preparation bars or the like.

[0023] Thereafter, in a ready-mix concrete pouring step S26, ready-mix concrete is poured and solidified to form the foundation body 22. As a result, the anchor frame 24, the anchor bolts 25, the fixing plates 26, the long nuts 27, and the reinforcing bars 28 are embedded in the foundation body 22, and only the tips of the long nuts 27 are exposed above the upper surface of the foundation framework 12, as shown in FIG.

[0024] Finally, in a slab forming step S27, a slab 23 is formed on the foundation body 22 formed in the ready-mix concrete pouring step S26.

[0025] Next, the seismic isolation device installation step S13 will be described in detail with reference to FIG. The seismic isolation device installation process S13 includes, for example, a base mortar installation process S31, a seismic isolation device temporary placement process S32, a bolt screwing process S33, and a grout filling process S34.

[0026] First, in a base mortar installation step S31, for example, as shown in FIG. 13, base mortar 14 is installed in the center surrounded by long nuts 27 exposed from the upper surface of the foundation framework 12 constructed in the foundation framework construction step S12.

[0027] Next, in a seismic isolation device temporary placement step S32, for example, as shown in FIG. 14, the seismic isolation device 13 is temporarily placed on the base mortar 14 placed in the base mortar placement step S31.

[0028] 15, for example, the bolt 15 is inserted into an insertion hole provided in the lower base plate of the seismic isolation device 13 temporarily placed in the seismic isolation device temporary placement step S32, and the tip of the inserted bolt 15 is screwed into a long nut 27 to fix the seismic isolation device 13. At this time, the planar back and horizontality of the seismic isolation device 13 are checked, and the lower base plate is adjusted so that it is accurately horizontal.

[0029] Finally, in a grout filling step S34, for example, as shown in FIG. 16, grout 16 is filled between the upper surface of the foundation framework 12 and the lower base plate of the seismic isolation device 13 that has been adjusted to be horizontal.

[0030] Since there is no need to provide a seismic isolation base between the foundation frame 12 and the seismic isolation device 13, the overall height of the seismic isolation structure 10 can be reduced, and the depth of excavation of the ground 90 can be made shallow. In addition, since there is no need to provide a seismic isolation base, the amount of work can be reduced. The stress transmitted from the seismic isolation device 13 to the foundation structure 12 is directly transmitted to the foundation main body 22 via the anchor bolts 25. This makes the stress transmission path clear. In addition, by shortening the distance between the seismic isolation device 13 and the foundation body 12, the additional bending moment generated in the foundation beam is reduced, and the load on the foundation body 12 can be reduced.

[0031] The above-described embodiment is an example for facilitating understanding of the present invention. The present invention is not limited thereto, and includes various modifications, changes, additions, or deletions without departing from the scope defined by the appended claims. This can be easily understood by those skilled in the art from the above description.

[0032] In recent years, seismic isolation structures have been adopted in many buildings to ensure earthquake safety. Therefore, streamlining the joints of seismic isolation devices through ingenuity has a large impact on costs, etc. In planning seismic isolation layers, it is desirable to reduce the height of the isolation layer and the amount of excavated soil from the perspective of reducing costs and environmental impact. However, in order to make it easier to install the anchor bolts, long nuts, and base plates used to connect the seismic isolation devices, and to ensure that concrete can be filled under the base plates, a common method is to build a structure called the seismic isolation base below the seismic isolation device (above the foundation structure) at a certain height. Therefore, by setting up a foundation column at the joint at the bottom of the seismic isolation device in the same way as a steel-framed column, the foundation below the seismic isolation is omitted, the height of the seismic isolation layer is lowered, and the amount of soil excavated is reduced. By omitting the foundation under the seismic isolation, providing reinforcement for the foundation columns, and directly connecting the seismic isolation device to the foundation body with anchor bolts, the stress transfer mechanism becomes clear. The distance between the seismic isolation device and the foundation body is shortened, and the additional bending moment generated in the foundation beams by the shear force acting on the seismic isolation device is reduced. By omitting the seismic isolation lower foundation, the relevant part of the structure is eliminated, and the process for constructing the lower foundation is omitted. The height of the seismic isolation layer can be reduced, and the amount of excavated soil can be reduced. Anchor bolts and long nuts are embedded in the foundation body, fixed with an anchor frame, and foundation concrete is poured. This makes it possible to omit the seismic isolation base foundation (cage reinforcement). In addition, by eliminating the process for the seismic isolation base foundation, the amount of soil excavated at the height of the seismic isolation layer can be reduced. The stress from the seismic isolation device is transmitted via the anchor bolt → foundation structure. To achieve this, column-shaped reinforcement is added to the foundation. This clarifies the stress transmission path. The distance between the seismic isolation device and the foundation structure is shortened, and the additional bending moment generated in the foundation beam is reduced, thereby reducing the load on the foundation structure. The long nuts and anchor bolts for connecting the seismic isolation device are installed using the position-maintaining anchor frame. The reinforcing bar work and formwork work for the foundation structure are carried out, and the anchor frame is surrounded by foundation column-shaped reinforcement and fixed via preparation reinforcement so that the position is fixed when concrete is poured. After pouring the concrete for the foundation structure, mortar is laid down and the seismic isolation device is temporarily placed in place. The seismic isolation device is fixed in place with bolts while checking its planar accuracy and horizontality. Non-shrink grout is filled under the seismic isolation device, completing the installation of the seismic isolation device. [Explanation of symbols]

[0033] 10 Seismic isolation structure, 12 Foundation frame, 13 Seismic isolation device, 14 Base mortar, 15 Bolt, 16 Grout, 21 Pile, 22 Foundation body, 23 Slab, 24 Anchor frame, 25 Anchor bolt, 26 Fixing plate, 27 Long nut, 28 Steel bar, 81 Column bar, 82 Tie bar, 90 Ground, 91 Underground beam recess, 92 Footing recess, S10 Seismic isolation structure construction process, S12 Foundation frame construction process, S13 Seismic isolation device installation process, S21 Excavation process, S22 Anchor frame installation process, S23 Anchor bolt fixing process, S24 Steel bar arrangement process, S25 Anchor frame fixing process, S26 Ready-mixed concrete pouring process, S27 Slab formation process, S31 Base mortar installation process, S32 Seismic isolation device temporary placement process, S33 Bolt screwing process, S34 grout filling process.

Claims

1. A foundation structure construction process for constructing a foundation structure in which anchor bolts and long nuts screwed onto the ends of the anchor bolts are embedded; a seismic isolation device installation process in which a seismic isolation device is placed on the foundation frame constructed in the foundation frame construction process, and the seismic isolation device is fixed to the foundation frame by screwing a bolt into the long nut; A method for constructing a seismic isolation structure comprising:

2. The foundation structure construction process includes: an anchor frame installation process for installing an anchor frame at a predetermined position; an anchor bolt fixing step of fixing the anchor bolt to the anchor frame; a long nut screwing process for screwing the long nut onto the tip of the anchor bolt; a reinforcing bar arrangement process for arranging reinforcing bars for the foundation framework to surround the anchor frame installed in the anchor frame installation process; an anchor frame fixing process of fixing the anchor frame to the reinforcing bar arranged in the reinforcing bar arrangement process; a ready-mixed concrete pouring process for pouring ready-mixed concrete to construct the foundation body in which the anchor bolts fixed in the anchor bolt fixing process and the long nuts screwed onto the anchor bolts in the long nut screwing process are embedded; The method for constructing a seismic isolation structure according to claim 1, comprising the steps of:

3. The length of the anchor bolt is longer than the height of the anchor frame. The method for constructing a seismic isolation structure according to claim 2.

4. The seismic isolation device installation process includes: A base mortar installation process of installing base mortar on the foundation structure; a seismic isolation device temporary placement process for temporarily placing the seismic isolation device on the base mortar installed in the base mortar installation process; a bolt screwing process in which the bolt is screwed into the long nut while checking the planar accuracy and horizontality of the seismic isolation device, thereby fixing the seismic isolation device temporarily placed in the seismic isolation device temporary placement process; a grout filling step of filling grout between the seismic isolation device and the foundation body; The method for constructing a seismic isolation structure according to any one of claims 1 to 3, comprising the steps of:

5. The foundation structure and An anchor bolt embedded in the foundation structure; A long nut embedded in the foundation body and screwed onto the tip of the anchor bolt; A seismic isolation device installed on the foundation structure; A bolt that fixes the seismic isolation device to the foundation body by screwing into the long nut. Equipped with a seismic isolation structure.

6. An anchor frame embedded in the foundation structure and having the anchor bolts fixed thereto. The seismic isolation structure of claim 5 , further comprising:

7. The length of the anchor bolt is longer than the height of the anchor frame. The seismic isolation structure according to claim 6.

8. A reinforcing bar embedded in the foundation structure and arranged to surround the anchor frame, to which the anchor frame is fixed. The seismic isolation structure according to claim 6 or 7, further comprising:

9. Grout filled between the seismic isolation device and the foundation structure The seismic isolation structure according to any one of claims 4 to 7, further comprising:

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