JP2017089349A - Base-isolated structure and construction method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a deterioration in performance of a base-isolating device.SOLUTION: A base-isolated structure 10 includes: a foundation 20; a plurality of inner columns 30 that are erected on the foundation 20; an upper structure 50 that is supported by the plurality of inner columns 30; a plurality of base-isolating devices 40 that are provided in the inner columns 30 so that the upper structure 50 can be relatively displaced in a horizontal direction with respect to the foundation 20; and a plurality of beams 70 that are joined to the adjacent inner columns 30 to assume a rectangular shape in a plan view.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a base isolation structure and a construction method of the base isolation structure.

  A seismic isolation structure including a column and a seismic isolation device installed at the column head of the column is known (see, for example, Patent Document 1).

JP 2008-38420 A

  By the way, when a seismic isolation device is installed at the column head of the column, if the column is bent and deformed during an earthquake, the seismic isolation device may be tilted, and the performance of the seismic isolation device may be reduced.

  In view of the above facts, an object of the present invention is to suppress performance degradation of the seismic isolation device.

  The seismic isolation structure according to claim 1 is provided in the lower structure, a plurality of pillars standing on the lower structure, an upper structure supported by the pillars, and the lower part. A plurality of seismic isolation devices that enable relative displacement of the upper structure in the horizontal direction with respect to the structure, and a plurality of beams that are joined to the adjacent pillars and have a rectangular or L shape in plan view; Is provided.

  According to the seismic isolation structure according to the first aspect, the upper structure is supported by the plurality of pillars that are erected on the lower structure. The plurality of columns are provided with seismic isolation devices that allow the upper structure to be displaced in the horizontal direction with respect to the lower structure.

  Here, a plurality of beams that are rectangular or L-shaped in plan view are joined to adjacent columns. Thereby, since the frame structure is comprised by the adjacent pillar and beam, the rigidity (bending rigidity) of a pillar is improved. Therefore, since the inclination etc. of the seismic isolation apparatus provided in the column are reduced, the performance fall of a seismic isolation apparatus is suppressed.

  Further, the plurality of beams are rectangular or L-shaped in plan view. In this case, two beams extending in two horizontal directions are joined to a predetermined column located at a rectangular or L-shaped corner. About the pillar located in this corner | angular part, the rigidity of two horizontal directions is improved. Therefore, the performance degradation of the seismic isolation device is further suppressed.

  The construction method of the seismic isolation structure according to claim 2 includes a column construction step of providing a pair of columns in the ground, a drilling step of excavating the ground and exposing the column heads of the pair of columns, A beam erection step of laying a beam on the column head of the column, and a seismic isolation device installation step of installing a seismic isolation device on each of the pair of column heads.

  According to the construction method of the seismic isolation structure which concerns on Claim 2, a pair of pillar is first provided in a ground in a pillar construction process. Next, in the excavation process, the ground is excavated to expose the column heads of the pair of columns. Next, in the beam erection step, a beam is erected on the column heads of the pair of columns. And in a seismic isolation apparatus installation process, a seismic isolation apparatus is installed on the column head of a pair of pillar.

  As described above, in the present invention, after installing the beam on the column heads of the pair of columns, the seismic isolation device is installed on the column heads of the pair of columns. Reduced. Therefore, the installation work of a seismic isolation apparatus becomes easy.

  Moreover, the rigidity (bending rigidity) of a pair of column is improved by constructing a beam on the column head part of a pair of column. Thereby, a deformation | transformation (bending deformation) of a pair of pillar at the time of an earthquake is reduced. Therefore, since the inclination of the seismic isolation device provided at the column heads of the pair of columns is reduced, the performance degradation of each seismic isolation device is suppressed.

  As described above, according to the present invention, it is possible to suppress the performance degradation of the seismic isolation device.

It is a top view which shows the seismic isolation floor of the base isolation structure to which the base isolation structure which concerns on one Embodiment was applied. FIG. 2 is a sectional view taken along line 2-2 of FIG. It is a partially expanded sectional view of FIG. FIG. 2 is a partially enlarged view of FIG. 1. (A)-(C) are longitudinal cross-sectional views explaining the construction method of the seismic isolation structure which concerns on one Embodiment. (A) And (B) is a longitudinal cross-sectional view explaining the construction method of the seismic isolation structure which concerns on one Embodiment. (A) And (B) is a schematic diagram equivalent to FIG. 3 which shows the inner pillar to which the modification of the seismic isolation structure which concerns on one Embodiment was applied. It is a top view equivalent to FIG. 2 which shows the inner pillar to which the modification of the seismic isolation structure which concerns on one Embodiment was applied.

  Hereinafter, the construction method of the base isolation structure and base isolation structure concerning one embodiment of the present invention is explained, referring to drawings. In addition, the arrow X direction and the arrow Y direction which are appropriately shown in each figure indicate two horizontal directions orthogonal to each other.

(Seismic isolation structure)
FIG. 1 shows a seismic isolation floor 12A of a base isolation structure 12 to which the base isolation structure 10 according to the present embodiment is applied. The seismic isolation structure 12 includes a foundation 20 as a lower structure, a plurality of outer peripheral columns 16 and inner columns 30 erected on the foundation 20, and a plurality of exemptions provided on the outer peripheral columns 16 and inner columns 30. The seismic devices 19 and 40 and the upper structure 50 (see FIG. 2) supported by the plurality of seismic isolation devices 19 and 40 are provided.

  The outer peripheral column 16 is, for example, a reinforced concrete structure (RC structure), and is arranged along the outer periphery of the seismic isolation structure 12. An RC outer wall 18 is provided between the adjacent outer peripheral columns 16. The outer wall 18 and the outer peripheral column 16 are integrated. Thereby, the rigidity (bending rigidity) of the outer peripheral column 16 is enhanced. In addition, seismic isolation devices 19 are respectively installed on the column heads of the outer peripheral columns 16.

  Inside the seismic isolation structure 12 (outer peripheral column 16), a plurality of inner columns 30 as columns are arranged in two horizontal directions (arrow X direction and arrow Y direction). The plurality of inner pillars 30 are CFT (Concrete Filled Steel Tube), as will be described later. Each inner column 30 has a smaller cross-sectional area than the outer peripheral column 16 and has lower rigidity (bending rigidity) than the outer peripheral column 16. Thus, the seismic isolation structure 10 which concerns on this embodiment is applied to the inner pillar 30 with low rigidity.

  That is, the beams 70 are respectively installed on the four inner pillars 30 arranged in two horizontal directions. These beams 70 have a rectangular shape (b-shape) in plan view. In other words, a rectangular plane frame 90 is formed by the four beams 70 in a plan view. In the present embodiment, the two planar frames 90 are discontinuously provided in an island shape. Hereinafter, the seismic isolation structure 10 which concerns on this embodiment is demonstrated concretely.

(Substructure)
As shown in FIG. 2, the foundation 20 as the lower structure is a pile foundation. The foundation 20 includes a plurality of concrete piles 22 embedded in the ground G, and a reinforced concrete foundation slab 24 provided on the ground G and supported by the plurality of concrete piles 22.

  The concrete pile 22 is a concrete cast-in-place pile. The foundation slab 24 is supported by the pile head portion 22U of the concrete pile 22. The foundation slab 24 forms a floor of the seismic isolation floor 12A of the base isolation structure 12. In the present embodiment, the foundation slab 24 forms a parking lot floor.

  In the concrete pile 22, a lower portion 26L of a structural pillar 26 is embedded. An upper portion 26U of the structural pillar 26 is raised upward from a pile head portion 22U of the concrete pile 22, and penetrates the foundation slab 24 in the vertical direction. Furthermore, the upper portion 26 </ b> U of the structural pillar 26 is raised upward from the upper surface of the foundation slab 24. An inner column 30 of the seismic isolation floor 12A is constituted by the upper portion 26U of the structural pillar 26.

  A beam 70 described later is joined to the column head 30U of the inner column 30. A seismic isolation device 40 is provided on the column head 30U of the inner column 30. That is, in this embodiment, the stigma-isolated structure is adopted. The seismic isolation device 40 is, for example, a laminated rubber bearing. An upper structure 50 is constructed on the seismic isolation device 40. The upper structure 50 is supported by the outer peripheral column 16 and the inner column 30 via the seismic isolation devices 19 and 40 (see FIG. 1). The upper structure 50 can be relatively displaced in the horizontal direction with respect to the foundation 20 as the lower structure by the plurality of seismic isolation devices 19 and 40.

(Superstructure)
The upper structure 50 includes a plurality of inner pillars 52 that are erected on each seismic isolation device 40 and beams 64 that are installed between the column base portions 52L of the adjacent inner pillars 52. The column base 52L of the inner column 52 is a column beam joint, and the end of the beam 64 is joined. The beam 64 is made of, for example, an H-shaped steel. A slab 66 is provided on the beam 64.

(Seismic isolation device)
As shown in FIG. 3, the seismic isolation device 40 is installed on the column head 30 </ b> U of the inner column 30. The inner pillar 30 (construction pillar 26) is made of CFT, for example, and includes a steel pipe pillar 32 and a concrete 34 filled in the steel pipe pillar 32. The column head 30U of the inner column 30 is formed in a trapezoidal shape whose width increases as it goes upward. A pair of diaphragms 36 is provided on the column head 30U.

  The pair of diaphragms 36 are, for example, through-diaphragms, and are arranged to face each other in the vertical direction. Each diaphragm 36 is formed with a through hole 38 for filling the concrete 34. A lower base plate 44 is provided on the upper surface of the upper diaphragm 36 via a plurality of adjustment ribs 42 for height adjustment. A lower flange portion 40L of the seismic isolation device 40 is joined to the lower base plate 44 by bolts and nuts (not shown). A fireproof coating concrete 46 is placed around the adjustment rib 42.

  The inner column 52 of the upper structure 50 is made of CFT and has a steel pipe column 54 and concrete 56 filled in the steel pipe column 54. The column base 52L of the inner column 52 is formed in a trapezoidal shape whose width increases as it goes downward. A pair of diaphragms 58 is provided on the column base 52L.

  The pair of diaphragms 58 are, for example, through diaphragms, and are arranged facing each other in the vertical direction. Each diaphragm 58 is formed with a through hole 59 for filling the concrete 56. An upper base plate 61 is provided on the lower surface of the lower diaphragm 58 through a plurality of adjustment ribs 60 for height adjustment. An upper flange portion 40U of the seismic isolation device 40 is joined to the upper base plate 61 by bolts and nuts (not shown). In addition, around the adjustment rib 60, concrete 62 for fireproof coating is placed.

(Beam)
As shown in FIG. 2, a beam 70 is installed on the column heads 30 </ b> U of a pair of adjacent inner columns 30. The beam 70 is made of, for example, an H-shaped steel. The beam 70 includes an upper and lower flange portion 70A and a web portion 70B that connects the upper and lower flange portions 70A. The ends of the beam 70 on both sides in the material axis direction are joined (rigidly joined) to the side surfaces of the column head 30U of the inner column 30 by welding or the like. As a result, a pair of adjacent inner pillars 30 and beams 70 constitute a ramen frame 72. In addition, the joining method of the inner pillar 30 and the beam 70 can be changed as appropriate.

  A vibration damping device 80 such as an oil damper is installed on the beam 70. That is, the beam 70 also functions as a gantry for installing the vibration damping device 80. The vibration damping device 80 is connected to the beam 70 and the beam 64 of the upper structure 50, and operates along with the operation (shear deformation) of the seismic isolation device 40 to absorb vibration energy. The vibration damping device 80 can be omitted as appropriate. Various facilities such as piping, wiring, and ducts can be installed on the beam 70.

  As shown in FIG. 4, four beams 70 each having a rectangular shape in a plan view are installed on four inner pillars 30 arranged in two horizontal directions. Specifically, a beam 70 is installed on the column heads 30U of a pair of inner columns 30 adjacent to each other in the arrow X direction. Thereby, the two frame frames 72 are formed in the direction of the arrow X. Similarly, a beam 70 is installed on the column heads 30U of the pair of inner columns 30 adjacent to each other in the arrow Y direction. Thereby, the two frame frames 72 are formed in the arrow Y direction. As a result, the rigidity of the four inner pillars 30 in the two horizontal directions (arrow X direction and arrow Y direction) is enhanced.

  Next, an example of the construction method of the seismic isolation structure which concerns on this embodiment is demonstrated.

  In this embodiment, the seismic isolation structure 12 is constructed by a so-called reverse driving method. Specifically, first, as shown in FIG. 5 (A), in the column construction process, a plurality of vertical holes for the concrete pile 22 are formed in the ground G, and concrete is placed in these vertical holes. A concrete pile 22 is formed. In addition, on the ground G, a retaining wall (not shown) is constructed along the outer periphery of the seismic isolation structure 12 (see FIG. 1).

  Next, the lower portions 26 </ b> L of the steel pipe columns 32 constituting the built-up columns 26 are inserted into the concrete piles 22 before hardening. At this time, the lower part 26 </ b> L of the construction column 26 is inserted into the concrete pile 22 so that the column head of the construction column 26 reaches a depth corresponding to the installation position (installation height) of the seismic isolation device 40. Moreover, after inserting the construction pillar 26 in the concrete pile 22, a vertical hole is refilled suitably.

  Next, as shown in FIG. 5 (B), in the excavation process (primary excavation process), the ground G is excavated, and the column heads of the adjacent pillars 26, that is, the column heads 30U of the adjacent inner columns 30 are removed. Expose. Next, concrete 34 (see FIG. 3) is filled in the steel pipe column 32 constituting the structural column 26 to form the CFT structural column 26. The inner pillar 30 of the seismic isolation floor 12A is formed by the upper part 26U of the structural pillar 26.

  Next, as shown in FIG. 5C, in the beam erection step, the beam 70 is erected on the column heads 30U of the pair of inner columns 30 adjacent in the arrow X direction. At this time, as shown in FIG. 4, the beam 70 is also installed on the column heads 30U of the pair of inner columns 30 adjacent to each other in the arrow Y direction.

  Next, as shown in FIG. 3, the lower base plate 44 is joined to the upper surface of the column head 30 </ b> U of the inner column 30 via a plurality of adjustment ribs 42. At this time, the height of the lower base plate 44 is adjusted by the adjustment rib 42.

  Next, as shown in FIG. 6 (A), in the seismic isolation device installation process, the base is separated on the lower base plate 44 (see FIG. 3) provided on the column heads 30U of the pair of adjacent inner columns 30. Each of the seismic devices 40 is installed, and the lower flange portion 40L of the seismic isolation device 40 and the lower base plate 44 are joined by a bolt or the like (not shown).

  Next, in the upper structure construction process, the inner column 52 and the beam 64 of the upper structure 50 are installed on the seismic isolation device 40. Further, as shown in FIG. 3, the upper base plate 61 is joined to the lower surface of the column base portion 52 </ b> L of the inner column 52 via the adjustment rib 60, and the upper base plate 61 and the upper flange portion 40 </ b> A of the seismic isolation device 40. Are joined by a bolt or the like (not shown). At this time, the position of the upper base plate 61 is appropriately adjusted by the adjustment rib 60.

  Next, as shown in FIG. 6B, an excavation process (secondary excavation process) is performed after the upper structure construction process or in parallel with the upper structure construction process. In this excavation process, the ground G is excavated until reaching the pile head 22U of the concrete pile 22, and the foundation slab 24 is constructed by placing concrete on the excavation bottom. Thereby, the seismic isolation floor 12A is formed.

  As described above, in this embodiment, after the beam 70 is installed on the column heads 30U of the pair of adjacent inner columns 30, the seismic isolation devices 40 are installed on the column heads 30U of the inner columns 30, respectively. Therefore, the inclination etc. of a pair of inner pillar 30 accompanying installation of the seismic isolation apparatus 40 are reduced. Therefore, the installation work of the seismic isolation device 40 becomes easy.

  Further, only the column heads 30U of the pair of adjacent inner columns 30 are exposed from the ground G, the beam 70 is installed on the column heads 30U, and the seismic isolation device 40 is installed on the column heads 30U. Thereby, the beam 70 and the seismic isolation device 40 can be constructed using the ground surface of the ground G as a scaffold. Therefore, the workability of the beam 70 and the seismic isolation device 40 is improved.

  In the excavation process (secondary excavation fixation), the ground G is excavated in a state where the beam 70 is installed on the column heads 30U of the pair of inner columns 30. Thereby, the inclination etc. of a pair of inner pillar 30 (construction pillar 26) accompanying excavation are suppressed.

  Next, the operation and effect of this embodiment will be described.

  According to the present embodiment, as shown in FIG. 2, the column head portion 30 </ b> U of the inner column 30 raised from the foundation slab 24 is joined to the inner column 52 of the upper structure 50 via the seismic isolation device 40. ing. That is, in this embodiment, the stigma-isolated structure is adopted. Thereby, since the height of seismic isolation floor 12A can be made high, effective use of seismic isolation floor 12A can be aimed at.

  On the other hand, when the column head 30U of the inner column 30 is joined to the inner column 52 of the upper structure 50 via the seismic isolation device 40, the fixing degree of the column head 30U is lowered, and the inner column 30 is in a cantilever state. It will be supported by the foundation slab 24. Therefore, the amount of bending deformation of the inner pillar 30 tends to increase during an earthquake. And if the amount of bending deformation of the inner pillar 30 becomes large, the seismic isolation device 40 may be inclined, and the performance of the seismic isolation device 40 may be reduced.

  On the other hand, in this embodiment, the beam 70 is constructed by the column head 30U of a pair of adjacent inner pillar 30. FIG. Thereby, since the frame structure 72 is comprised by a pair of adjacent inner pillar 30 and the beam 70, the rigidity (bending rigidity) of a pair of inner pillar 30 is improved. Therefore, since the inclination etc. of the seismic isolation apparatus 40 provided in a pair of inner pillar 30 are reduced, the performance fall of the seismic isolation apparatus 40 is suppressed.

  Further, as shown in FIG. 4, four beams 70 having a rectangular shape in a plan view are installed on four inner pillars 30 arranged in two horizontal directions (arrow X direction and arrow Y direction). ing. Specifically, a beam 70 is installed on the column heads 30U of a pair of inner columns 30 adjacent to each other in the arrow X direction. Thereby, the two frame frames 72 are formed in the direction of the arrow X. Similarly, a beam 70 is installed on the column heads 30U of the pair of inner columns 30 adjacent to each other in the arrow Y direction. Thereby, the two frame frames 72 are formed in the arrow Y direction.

  Therefore, in the present embodiment, the rigidity in the two horizontal directions (arrow X direction and arrow Y direction) is increased for the four inner pillars 30. Therefore, the performance fall of the seismic isolation apparatus 40 installed in the column head 30U of the four inner pillars 30 is further suppressed.

  By the way, in the seismic isolation floor 12A, the ceiling height is partially lowered at the portion where the beam 70 is installed. On the other hand, in this embodiment, as shown in FIG. 1, two planar frames 90 that are rectangular in plan view are arranged in an island shape without being continuous. Accordingly, for example, a path such as a large bus can be formed between the two plane frames 90 while using the space below each plane frame 90 as a parking space for an ordinary car or the like. Therefore, effective use of the seismic isolation floor 12A can be achieved. Furthermore, the two plane frames 90 can be used as a core part of the seismic isolation structure 12, for example.

  In addition, as shown in FIG. 2, a vibration damping device 80 or the like can be installed on the beam 70 installed on the column heads 30 </ b> U of the pair of inner columns 30. Therefore, it is not necessary to install a stand for the vibration damping device 80 separately from the beam 70, so that the cost can be reduced.

  Next, a modification of the above embodiment will be described.

  In the said embodiment, although the seismic isolation apparatus 40 was installed in the column head 30U of the inner pillar 30, the said embodiment is not restricted to this. For example, as shown in FIG. 7A, the seismic isolation device 40 may be installed between the column base 30 </ b> L of the inner column 30 and the foundation slab 24. In this case, the bending rigidity of the inner column 30 can be efficiently increased by installing the beam 70 between the column bases 30L of the pair of adjacent inner columns 30.

  Further, for example, as shown in FIG. 7B, the inner pillar 30 is divided into a lower inner pillar 91 and an upper inner pillar 92, and between these lower inner pillar 91 and upper inner pillar 92. A seismic isolation device 40 may be installed. In this case, the rigidity of the lower inner column 91 can be efficiently increased by installing the beam 70U on the column heads 91U of the pair of adjacent lower inner columns 91. Moreover, the rigidity of the upper inner pillar 92 can be efficiently increased by installing the beam 70L on the column base 30L of the pair of adjacent upper inner pillars 92 adjacent to each other. One of the beam 70U and the beam 70L may be omitted.

  Moreover, in the said embodiment, although the some beam 70 which comprised rectangular shape by planar view was constructed in the some inner pillar 30 arranged in two horizontal directions, the said embodiment is not restricted to this. For example, as shown in FIG. 8, a plurality of (two) beams 70 having an L shape in a plan view may be installed on a plurality of inner pillars 30 arranged in two horizontal directions. In this case, the rigidity of the inner column 30 to which the beam 70 is joined is increased. Therefore, the performance fall of the seismic isolation apparatus 40 provided in the said inner pillar 30 is suppressed.

  In addition, with respect to the inner column 30 located at the L-shaped corner C, a beam 70 extending in two horizontal directions is joined. Therefore, about the inner pillar 30 of the corner | angular part C, the rigidity of two horizontal directions (arrow X direction and arrow Y direction) is improved. Therefore, the performance fall of the seismic isolation apparatus 40 installed in the inner pillar 30 of the corner | angular part C is further suppressed.

  Further, for example, a stiffening member such as a horizontal brace or a floor (slab) is provided between the plurality of beams 70 that are rectangular or L-shaped in plan view, and the rigidity of the inner column 30 to which the beams 70 are joined is increased. It can be further increased.

  Moreover, in the said embodiment, although the beam 70 was constructed between a pair of inner pillars 30 in the seismic isolation floor 12A, for example, the beam 70 may be constructed between the inner pillar 30 and the outer peripheral pillar 16, or a pair of A beam 70 may be installed between the outer peripheral columns 16.

  Moreover, in the said embodiment, although the inner pillar 30 is made into CFT structure, the inner pillar 30 may be steel frame structure, RC structure, SRC structure, etc. Similarly, in the above embodiment, the beam 70 is a steel structure, but the beam 70 may be an RC structure, an SRC structure, or the like.

  In the above embodiment, the seismic isolation device 40 is a laminated rubber bearing. However, the seismic isolation device may be, for example, a sliding bearing or a rolling bearing.

  Moreover, in the said embodiment, although the seismic isolation structure 12 is made into an underground foundation seismic isolation, the said embodiment is not restricted to this. The seismic isolation structure 10 according to the above embodiment can also be applied to the intermediate floor (intermediate floor seismic isolation) of the base isolation structure 12.

  Moreover, in the said embodiment, although the seismic isolation structure 12 was constructed | assembled by what is called a reverse driving method, you may form the seismic isolation structure 12 with another construction method.

  As mentioned above, although one embodiment of the present invention was described, the present invention is not limited to such an embodiment, and one embodiment and various modifications may be used in combination as appropriate, and the gist of the present invention will be described. Of course, various embodiments can be implemented without departing from the scope.

10 Seismic isolation structure 12 Seismic isolation structure 20 Foundation (lower structure)
30 Inner pillar (pillar)
30U Column head 40 Seismic isolation device 50 Upper structure 70 Beam 70U Beam 70L Beam

Claims (2)

A substructure,
A plurality of pillars standing on the lower structure;
An upper structure supported by a plurality of the pillars;
A plurality of seismic isolation devices that are provided on the pillar and that allow the upper structure to be displaced relative to the lower structure in a horizontal direction;
A plurality of beams that are joined to adjacent columns and have a rectangular or L shape in plan view;
Seismic isolation structure with Pillar construction process to provide a pair of pillars in the ground,
An excavation step of excavating the ground to expose the column heads of the pair of columns;
A beam erection step of erected a beam on the column heads of the pair of columns;
A seismic isolation device installation step of installing a seismic isolation device on the column heads of the pair of columns,
Construction method of seismic isolation structure with

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