Seismic isolation building structure

Abstract

To provide a seismic isolation building structure capable of suppressing tilting of a seismic isolation device due to loads applied from columns.SOLUTION: A seismic isolation building structure 1 comprises: a substructure 10 adhered to the ground 3; a seismic isolation device 20 installed in the substructure 10; a pillar 11 attached to a top surface 24 of the seismic isolation device 20; and at least one beam 12 connected to the pillar 11. In the seismic isolation building structure 1, at least one beam 12 is connected to the pillar 11 so that a span of the beam 12 is asymmetrical on one side where the beam 12 extends from the axis O1 of the pillar 11, and on the other side that is opposite side of the one side across the axis O1 of the pillar 11, which are both sides with respect to the axis O1 of the pillar 11, and the axis O2 of the seismic isolation device 20 is offset to a longer side of the beam 12 on one side or the other side with respect to the axis O1 of the pillar 11.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a seismic isolation building structure.

Background Art

[0002] For example, as a building structure such as an office building, a seismic isolation device is installed in a lower structure such as a foundation fixed to the ground, and columns constituting the building body are attached to the upper surface of the seismic isolation device, so that an upper structure including columns and beams of the building is isolated from seismic vibrations by the seismic isolation device. Such a seismic isolation structure is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above conventional seismic isolation building structure, since the axis of the seismic isolation device and the axis of the column attached to its upper surface coincide, for example, when the beam is connected only to one side across the axis of the column, if the magnitude of the load applied from the beam to the column is asymmetric across the axis of the column, there is a problem that a load biased with respect to the axis is applied from the column to the seismic isolation device, and the seismic isolation device may tilt. When the seismic isolation device tilts, problems such as the column tilting and the bending of the beam increasing will occur.

[0005] The present invention has been made in view of such problems, and an object thereof is to provide a seismic isolation building structure capable of suppressing the occurrence of tilting of the seismic isolation device due to the load applied from the column.

Means for Solving the Problems

[0006] The seismic isolation building structure of the present invention includes a lower structure fixed to the ground, a seismic isolation device installed on the lower structure, a column attached to the upper surface of the seismic isolation device, and at least one beam connected to the column. The seismic isolation building structure is characterized in that at least one of the beams is connected to the column such that the span of the beam is asymmetric on both sides sandwiching the axis of the column, that is, on one side where the beam extends from the axis of the column and on the other side opposite to the one side across the axis of the column, and the axis of the seismic isolation device is displaced toward the side where the span of the beam is longer among the one side and the other side with respect to the axis of the column.

[0007] In the seismic isolation building structure of the present invention, in the above configuration, it is preferable that the beam is connected only to the one side sandwiching the axis of the column, and the axis of the seismic isolation device is displaced toward the side to which the beam is connected with respect to the axis of the column.

[0008] In the seismic isolation building structure of the present invention, in the above configuration, beams having different spans are connected to the one side and the other side sandwiching the axis of the column, and it is preferable that the axis of the seismic isolation device is displaced toward the side to which the beam having the longer span is connected with respect to the axis of the column.

[0009] In the seismic isolation building structure of the present invention, in the above configuration, it is further preferable to include a base plate joined to the lower end of the column and fixed to the upper surface of the seismic isolation device, and a rib member joined between the column and the base plate and extending from the column toward the side where the axis of the seismic isolation device is eccentric with respect to the axis of the column.

Advantages of the Invention

[0010] According to the present invention, it is possible to provide a seismic isolation building structure capable of suppressing the occurrence of inclination in the seismic isolation device due to the load applied from the column.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0012] Hereinafter, the seismic isolation building structure 1 of the embodiment of the present invention will be exemplified and described in detail with reference to the drawings.

[0013] The building 2 shown in FIGS. 1 and 2 is one to which the seismic isolation building structure 1 of an embodiment of the present invention is applied. In this embodiment, the building 2 is an office building having a plurality of floors. Note that the building 2 is not limited to an office building and may be used for other purposes.

[0014] The seismic isolation building structure 1 has a lower structure body 10 fixed to the ground 3. In this embodiment, the lower structure body 10 is a reinforced concrete foundation of the building 2. Note that the lower structure body 10 is not limited to the foundation of the building 2 as long as it is fixed to the ground 3.

[0015] The seismic isolation building structure 1 has a plurality of columns 11 constituting the frame 4 of the building 2 and a plurality of beams 12 connected to the corresponding columns 11 at both ends. In this embodiment, the plurality of columns 11 are each formed of square steel pipes, and the plurality of beams 12 are each formed of H-shaped steel.

[0016] In this embodiment, the building frame 4 has a structure in which a plurality of columns 11 and a plurality of beams 12 are arranged in a ladder shape in plan view on each floor. That is, with respect to the direction (the vertical direction in the drawing of FIG. 2) that horizontally extends parallel to both side surfaces (the side surfaces facing left and right in FIG. 2) of the building 2, six columns 11 are arranged at intervals on one side and the other side in this direction, and a plurality of (six) beams 12 extending in this direction are joined to a corresponding pair of columns 11, respectively. Thus, the building frame 4 has a one-span structure with respect to the direction that horizontally extends parallel to both side surfaces of the building 2. On the other hand, the plurality of (ten) beams 12 arranged to horizontally extend parallel to the front surface and the back surface (the surfaces facing up and down in FIG. 2) of the building 2 are joined to a corresponding pair of columns 11 out of the six columns 11 arranged at intervals on the front surface side or the back surface side, respectively. Thus, the building frame 4 has a structure divided into a plurality of spans with respect to the direction (the left-right direction in the drawing of FIG. 2) that horizontally extends parallel to the front surface and the back surface of the building 2.

[0017] One of the columns 11 shown in FIG. 1 is arranged in the middle of the two side surfaces on the front surface side of the building 2 of the building frame 4, and the other column 11 shown in FIG. 1 is arranged in the middle of the two side surfaces on the back surface side of the building 2 of the building frame 4. That is, one beam 12 that horizontally extends parallel to the two side surfaces of the building 2 is joined to one of the columns 11 and the other column 11 shown in FIG. 1 so as to span across these columns 11. In addition, two beams 12 that horizontally extend parallel to the front surface and the back surface of the building 2 are joined to each column 11. In this embodiment, the joining of the beam 12 to the column 11 is a rigid joint.

[0018] A seismic isolation device 20 is installed in the substructure 10. In this embodiment, the substructure 10 has a plurality of cube-shaped pedestal portions 10a arranged at positions corresponding to the columns 11, respectively, and the seismic isolation devices 20 are installed on the upper surfaces of these pedestal portions 10a, respectively. Note that it is also possible to provide a pile (not shown) buried in the ground 3 below the pedestal portion 10a to support the load of the pedestal portion 10a with the pile.

[0019] As shown in FIG. 3, as the seismic isolation device 20, a structure in which a seismic isolation laminated rubber 23 is disposed between an upper flange 21 and a lower flange 22 spaced apart vertically can be used. In this case, the seismic isolation device 20 is fixed to the upper surface of the pedestal portion 10a of the lower structure 10 at the lower flange 22 using fastening means (not shown) such as bolts.

[0020] Note that the seismic isolation device 20 is not limited to the above configuration, and for example, other configurations such as a sliding bearing type, a rolling bearing type, and a sliding pendulum type may be used.

[0021] Each column 11 is attached to the upper surface 24 of the corresponding seismic isolation device 20. In the present embodiment, a rectangular plate-shaped base plate 13 formed of steel or the like is joined to the lower end of each column 11 by welding or the like, and this base plate 13 is fixed to the upper surface 24 of the upper flange 21 of the seismic isolation device 20 using fastening means such as bolts, whereby the column 11 is attached to the upper surface 24 of the seismic isolation device 20.

[0022] At least one beam 12 is connected to each column 11 on both sides sandwiching the axis O1 of the column 11, such that the span of the beam 12 is asymmetric between one side from which the beam 12 extends from the axis O1 of the column 11 and the other side opposite to one side across the axis O1 of the column 11. One side sandwiching the axis O1 of the column 11 extends from the axis O1 of the column 11 in the first direction with a straight line passing through the axis O1 of the column 11 and perpendicular to the first direction (in FIG. 3, the right direction on the paper surface with respect to the axis O1 of the column 11) in which the beam 12 extends as a boundary with the other side. The other side sandwiching the axis O1 of the column 11 extends in the direction opposite to the first direction from the axis O1 of the column 11. For example, in the columns 11 shown in FIGS. 1 and 3, the beam 12 is connected only to one side sandwiching the axis O1.

[0023] Here, on both sides sandwiching the axis O1 of the column 11, on one side that spreads in the first direction in which the beam 12 extends from the axis O1 of the column 11, and on the other side that spreads in the direction opposite to the first direction across the axis O1 of the column 11, in a configuration where at least one beam 12 is connected to the column 11 so that the span of the beam 12 becomes asymmetric, a load is applied asymmetrically to the column 11 from the beam 12 across the axis O1. Therefore, if the axis O2 of the seismic isolation device 20 coincides with the axis O1 of the column 11 attached to its upper surface 24, there is a risk that a load biased with respect to the axis O2 is applied to the seismic isolation device 20 from the column 11, causing the seismic isolation device 20 to tilt.

[0024] Therefore, in the seismic isolation building structure 1 according to the present embodiment, in a configuration where at least one beam 12 is connected to the column 11 so that the span of the beam 12 is asymmetric on both sides sandwiching the axis O1 of the column 11, on one side that spreads in the first direction in which the beam 12 extends from the axis O1 of the column 11, and on the other side that spreads in the direction opposite to the first direction across the axis O1 of the column 11, the axis O2 of the seismic isolation device 20 to which the column 11 is attached is shifted and arranged with respect to the axis O1 of the column 11 to the side where the span of the beam 12 is longer among one side and the other side sandwiching the axis O1. That is, in the seismic isolation building structure 1 according to the present embodiment, the seismic isolation device 20 is arranged eccentrically with respect to the column 11 on the side where the load applied by at least one beam 12 to the column 11 is biased with respect to the axis O1.

[0025] For example, as shown in FIGS. 1 and 3, when the beam 12 is connected only to one side sandwiching the axis O1 of the column 11, since the span of the beam 12 on the other side sandwiching the axis O1 of the column 11 is 0, it is considered that the span of the beam 12 connected to one side sandwiching the axis O1 of the column 11 is longer than the span of the beam 12 on the other side, and the axis O2 of the seismic isolation device 20 is shifted and arranged to the side where the beam 12 is connected with respect to the axis O1 of the column 11.

[0026] The axis O2 of the seismic isolation device 20 is a vertical axis that, in a natural state (non-operating state), passes through the center of the portion that supports the load of the column 11 and is provided between the portion fixed to the lower structure 10 of the seismic isolation device 20 and the portion to which the column 11 is attached in a plan view. For example, when the seismic isolation device 20 has a configuration in which the seismic isolation laminated rubber 23 is disposed between the upper flange 21 and the lower flange 22, it is a vertical axis passing through the center of the seismic isolation laminated rubber 23 that has a cylindrical shape in a plan view in the natural state (non-operating state). When the seismic isolation device 20 is of the sliding bearing type, it is a vertical axis passing through the center of the stationary slider between the portion fixed to the lower structure 10 of the seismic isolation device 20 and the portion to which the column 11 is attached in a plan view in the natural state (non-operating state). When the seismic isolation device 20 is of the rolling bearing type, it is a vertical axis passing through the center of the stationary rolling element between the portion fixed to the lower structure 10 of the seismic isolation device 20 and the portion to which the column 11 is attached in a plan view in the natural state (non-operating state). When the seismic isolation device 20 is of the sliding pendulum type, it is a vertical axis passing through the center of the stationary pendulum body between the portion fixed to the lower structure 10 of the seismic isolation device 20 and the portion to which the column 11 is attached in a plan view in the natural state (non-operating state).

[0027] The eccentricity (the distance between the axis O2 of the seismic isolation device 20 and the axis O1 of the column 11) of the axis O2 of the seismic isolation device 20 with respect to the axis O1 of the column 11 can be set as appropriate, but it is preferably set such that the load is evenly applied to both sides of the axis O2 of the seismic isolation device 20 with the column 11 in between.

[0028] In FIGS. 1 and 3, since the beams 12 of the same span are connected to both sides in the direction perpendicular to the paper surface across the axis O1 of the column 11, with respect to this direction, the axis O2 of the seismic isolation device 20 is not eccentric with respect to the axis O1 of the column 11.

[0029] As described above, in the seismic isolation building structure 1 according to the present embodiment, at least one beam 12 is connected to the column 11 such that the spans of the beams 12 are asymmetric on one side and the other side with respect to the axis O1 of the column 11. In this configuration, the axis O2 of the seismic isolation device 20 to which the column 11 is attached is displaced and arranged toward the side where the span of the beam 12 is longer, either on one side or the other side, with respect to the axis O1 of the column 11. Therefore, compared to the case where the axis O2 of the seismic isolation device 20 is arranged coaxially with the axis O1 of the column 11, the bias of the load applied from the column 11 to the seismic isolation device 20 can be reduced, and it is possible to suppress the occurrence of inclination in the seismic isolation device 20 due to the load applied from the column 11.

[0030] In particular, when the amount of eccentricity of the axis O2 of the seismic isolation device 20 with respect to the axis O1 of the column 11 is set to the amount of eccentricity at which loads are uniformly applied to both sides of the axis O2 of the seismic isolation device 20 from the column 11, it is possible to eliminate the occurrence of inclination in the seismic isolation device 20 due to the load applied from the column 11.

[0031] Further, by suppressing the occurrence of inclination in the seismic isolation device 20 due to the load applied from the column 11, it is possible to suppress the column 11 attached to the seismic isolation device 20 from inclining together with the seismic isolation device 20 and increasing the bending due to the self-weight of the beam 12 connected to the column 11.

[0032] As shown in FIGS. 3 and 4, the seismic isolation building structure 1 according to the present embodiment can be configured such that a rib member 30 extending from the column 11 toward the side where the axis O2 of the seismic isolation device 20 is eccentric with respect to the axis O1 of the column 11 is joined between the column 11 and the base plate 13.

[0033] In the present embodiment, the rib member 30 is formed in a rectangular plate shape by a steel plate, and at one side end thereof, it is joined to the side surface of the column 11 on the side where the axis O2 of the seismic isolation device 20 of the column 11 is eccentric with respect to the axis O1 of the column 11 by welding, and at its lower end, it is joined to the upper surface of the base plate 13 by welding.

[0034] Since the axis O2 of the seismic isolation device 20 is eccentric with respect to the axis O1 of the column 11, the overhang amount of the portion of the base plate 13 on the side where the axis O2 of the seismic isolation device 20 is eccentric with respect to the axis O1 of the column 11 from the column 11 is larger than the overhang amount of the other portion of the base plate 13 from the column 11. However, by providing the rib member 30 on the portion of the base plate 13 on the side where the axis O2 of the seismic isolation device 20 is eccentric with respect to the axis O1 of the column 11 with respect to the column 11, the portion can be reinforced by the rib member 30. Thereby, when the seismic isolation device 20 performs a seismic isolation operation during an earthquake or the like, deformation of the portion of the base plate 13 fixed to the upper surface 24 of the seismic isolation device 20 on the side where the axis O2 of the seismic isolation device 20 is eccentric with respect to the axis O1 of the column 11 due to the pulling force generated in the column 11 can be suppressed, and the seismic isolation device 20 can function more effectively.

[0035] In the present embodiment, the rib member 30 is also joined by welding to the lower surface (lower flange) of the beam 12 connected to the column 11 at its upper end. Thereby, the portion of the base plate 13 on the side where the axis O2 of the seismic isolation device 20 is eccentric with respect to the axis O1 of the column 11 with respect to the column 11 can be more effectively reinforced by the rib member 30. Thereby, when the seismic isolation device 20 performs a seismic isolation operation during an earthquake or the like, deformation of the portion of the base plate 13 fixed to the upper surface 24 of the seismic isolation device 20 on the side where the axis O2 of the seismic isolation device 20 is eccentric with respect to the axis O1 of the column 11 due to the pulling force generated in the column 11 can be more effectively suppressed.

[0036] In the present embodiment, between the column 11 and the base plate 13, a pair of other rib members 31 are joined on both sides of the rib member 30 in a posture inclined with respect to the rib member 30. Also, a pair of other rib members 32 are joined to both side surfaces that are orthogonal and continuous to the side surface of the column 11 to which the rib member 30 is joined. These rib members 31, 32 are also joined to the lower surface of the corresponding beam 12. With such a configuration, each part of the base plate 13 can be reinforced, and deformation of the base plate 13 can be more effectively suppressed.

[0037] Note that the rib member 30 is larger in size than the rib members 32 joined to both side surfaces of the column 11 that are continuous and orthogonal to the side surface to which the rib member 30 is joined. Thereby, the portion of the base plate 13 on the side where the axis O2 of the seismic isolation device 20 is eccentric with respect to the axis O1 of the column 11 can be effectively reinforced by the rib member 30.

[0038] The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist thereof.

[0039] For example, in the above-described embodiment, the case where the beam 12 is connected only to one side of the column 11 with the axis O1 of the column 11 interposed therebetween has been described. However, as shown in FIG. 5, a short-span beam 12a is connected to one side of the column 11 with the axis O1 of the column 11 interposed therebetween (left side in FIG. 5), and a beam 12b having a longer span than the beam 12a (different span from the beam 12a) is connected to the other side of the column 11 with the axis O1 of the column 11 interposed therebetween (right side in FIG. 5). In this case, the axis O2 of the seismic isolation device 20 may be displaced and arranged on the side of the beam 12b having a longer span than the beam 12a with respect to the axis O1 of the column 11.

[0040] Also, for example, as in the case of the column 11 arranged at the corner portion of the building 2 in FIG. 2, when two beams 12, i.e., a beam 12 extending in the vertical direction of the paper surface of FIG. 2 and a beam 12 extending in the horizontal direction of the paper surface of FIG. 2, are connected to the column 11, the axis O2 of the seismic isolation device 20 may be arranged within a range surrounded by the beam 12 extending in the horizontal direction and the beam 12 extending in the vertical direction in a plan view perpendicular to the paper surface of FIG. 2.

[0041] Thereby, compared with the case where the axis O2 of the seismic isolation device 20 is arranged coaxially with the axis O1 of the column 11, the bias of the load applied from the column 11 to the seismic isolation device 20 can be reduced, and the occurrence of inclination of the seismic isolation device 20 due to the load applied from the column 11 can be suppressed.

Explanation of Reference Numerals

[0042] 1 Seismic isolation building structure 2 Building 3 Ground 4 Body 10 Lower Structure 10a Pedestal Part 11 Column 12 Beam 12a Beam 12b Beam 13 Base Plate 20 Seismic Isolation Device 21 Upper Flange 22 Lower Flange 23 Seismic Isolation Laminated Rubber 24 Upper Surface 30 Rib Member 31 Rib Member 32 Rib Member O1 Axis of Column O2 Axis of Seismic Isolation Device

Claims

1. A seismically isolated building structure having a substructure fixed to the ground, a seismic isolation device installed on the substructure, a column attached to an upper surface of the seismic isolation device, and at least one beam connected to the column, At least one of the beams is connected to the column such that the span of the beam is asymmetric between one side where the beam extends from the axis of the column and the other side opposite to the one side across the axis of the column, A seismically isolated building structure, characterized in that the axis of the seismic isolation device is shifted relative to the axis of the column to the side having the longer span of the beam, between the one side and the other side.

2. The beam is connected only to the one side of the axis of the column, The seismic isolation building structure according to claim 1 , wherein the axis of the seismic isolation device is offset from the axis of the column toward the side to which the beam is connected.

3. The beams having different spans are connected to the one side and the other side of the axis of the column, The seismic isolation building structure according to claim 1 , wherein the axis of the seismic isolation device is shifted toward the side to which the beam having a long span is connected with respect to the axis of the column.

4. A base plate joined to the lower end of the column and fixed to an upper surface of the seismic isolation device; A seismically isolated building structure as described in any one of claims 1 to 3, further comprising a rib member joined between the column and the base plate and extending from the column toward the side where the axis of the seismic isolation device is eccentric relative to the axis of the column.

Images