JP6778065B2 - Building frame structure - Google Patents

Description

The present invention relates to a building frame structure.

Conventionally, as a frame structure of a building, the one described in Patent Document 1 is known. This frame structure has a plurality of columns and beams connecting them in the horizontal direction. In addition, a seismic isolation device is provided at the bottom of the building to ease the vibration of the building in the event of an earthquake or the like. Seismic isolation devices are provided at the bottom of each pillar.

Japanese Unexamined Patent Publication No. 61-179972

However, in the frame structure of the building as described above, there is a problem that the cost increases and the construction period becomes long because the seismic isolation device and the basic structure for the seismic isolation device are provided under each pillar. Therefore, it has been required to ensure seismic isolation performance while simplifying the seismic isolation structure (reducing the number of seismic isolation devices) by rationalizing the seismic isolation structure.

An object of the present invention is to provide a frame structure of a building capable of ensuring seismic isolation performance while simplifying the seismic isolation structure.

The frame structure of the building according to the present invention is a frame structure of a building, in which a plurality of first pillars extending in the vertical direction and a plurality of second pillars extending in the vertical direction between the first pillars are horizontally arranged. It is provided with a plurality of beams extending in a direction and a seismic isolation device provided at the bottom of the building, and the seismic isolation device is provided at the bottom of the first column and not at the bottom of the second column. The joint between the second column and the beam may be a rigid joint.

According to the frame structure according to the present invention, the seismic isolation device is provided at the lower part of the first pillar, but is not provided at the lower part of the second pillar, and is omitted. According to such a structure, a long-term axial force acts on the first column and horizontal rigidity is ensured. On the other hand, since the second pillar is not provided with a seismic isolation device at the lower part, the long-term axial force is applied to the first pillar with almost no burden on the long-term axial force. As a result, a compressive force acts on the seismic isolation device, so that the tensile force generated in the seismic isolation device below the first pillar during an earthquake can be reduced. On the other hand, the joint between the second column and the beam is a rigid joint. With such a structure, a horizontal force can be transmitted to the second column. Therefore, the second column can support the horizontal force, and the horizontal rigidity of the frame structure can be increased. In this way, since the second column can support the horizontal force, the horizontal rigidity of the frame structure can be ensured by the second column together with the first column. From the above, seismic isolation performance can be ensured.

Further, in the frame structure of the building according to the present invention, a tube frame configured by a first column, a second column, and a beam so as to surround the central axis when viewed from above may be provided. With such a configuration, the horizontal rigidity of the frame structure can be increased, so that seismic isolation can be effectively performed even when the number of seismic isolation devices is reduced.

Further, in the frame structure of the building according to the present invention, the second pillar may be composed of members having a strong axis direction and a weak axis direction. Since the load of the long-term axial force on the second column is extremely small and only the horizontal rigidity needs to be secured, the amount of steel frame of the building can be reduced by setting the direction in which the strength is unnecessary to the weak axis direction.

Further, in the frame structure of the building according to the present invention, the first pillar may be composed of members having a strong axis direction and a weak axis direction. As for the first column, the amount of steel frame in the building can be reduced by setting the direction in which the strength is unnecessary to be the weak axis direction.

Further, in the frame structure of the building according to the present invention, the second pillar may be provided on the lower layer side of the building and may be omitted from the upper layer side. Since the horizontal rigidity to be secured in the upper layer may be small, the second column can be omitted. Therefore, by omitting the second pillar in the upper layer, the space in the upper layer can be widely used.

According to the present invention, seismic isolation performance can be ensured while simplifying the seismic isolation structure.

FIG. 1 is a schematic configuration diagram of a building frame structure according to an embodiment of the present invention. FIG. 2 is a view of the frame structure shown in FIG. 1 as viewed from above. FIG. 3 is a diagram showing a frame structure according to a modified example. FIG. 4 is a diagram showing a frame structure according to a modified example. FIG. 5 is a schematic view showing a long-term axial force and a horizontal force at the time of an earthquake acting on the frame structure according to the embodiment. FIG. 6 is a schematic configuration diagram showing a frame structure according to a comparative example. FIG. 7 is a schematic view showing a long-term axial force and a horizontal force at the time of an earthquake acting on the frame structure according to the comparative example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements are designated by the same reference numerals, and duplicate description will be omitted.

As shown in FIGS. 1 and 2, the frame structure 100 of the building 1 includes a plurality of first columns 2 extending in the vertical direction and a plurality of second columns 3 extending in the vertical direction between the first columns 2. A plurality of beams 4 extending in the horizontal direction and a seismic isolation device 10 provided at the lower part of the building 1 are provided. Here, as the frame structure 100, the frame structure of a rectangular parallelepiped high-rise building is exemplified. In the following description, one direction in the horizontal direction may be referred to as "X-axis direction", and the direction orthogonal to one direction in the horizontal direction may be referred to as "Y-axis direction". Further, in the following description, the first pillar 2 and the second pillar 3 are not distinguished, and one of the pillars may be referred to as "pillar 5".

The first column 2 is a structural column for bearing a long-term axial force and also bearing a horizontal force to secure horizontal rigidity. The first pillar 2 is made of a member having no weak axial direction, and is made of, for example, a square steel pipe or the like. The first pillar 2 is a pillar in which the seismic isolation device 10 is provided below the pillar 2. However, the first pillar 2 may be composed of a member having a strong axial direction and a weak axial direction, such as H-shaped steel. Alternatively, some of the first pillars 2 are composed of members having no weak axial direction, and some other first pillars 2 are composed of members having weak axial directions and strong axial directions. May be good. For example, the first column 2 at the four corners of the frame structure 100 is composed of a square steel pipe (a member having no weak axis direction), and the first column 2 in the other portion is an H-shaped steel (a member having a weak axis). It may be composed of. When the second pillar 3 described later is made of H-shaped steel, the first pillar 2 and the second pillar 3 do not have to have the same size. For example, the flange thickness of the first pillar 2 may be increased. The strength may be increased by increasing the thickness.

The second pillar 3 is not intended to bear a long-term axial force, but is a pillar whose main purpose is to bear a horizontal force to secure horizontal rigidity. The second pillar 3 may be composed of members having a strong axial direction and a weak axial direction. That is, since it is not necessary for the second pillar 3 to bear the axial force, the uniaxial direction may be the weak axial direction. The second column 3 may be composed of columns that support the bending moment and the shearing force. For example, the second column 3 may be composed of H-shaped steel, a rectangular steel pipe, RC having a rectangular cross section, or the like. The second pillar 3 is a pillar from which the seismic isolation device 10 is omitted from below.

The beam 4 is a member that extends horizontally between the columns 5 and connects the columns 5. The beam 4 is made of H-shaped steel or the like. The joint between the beam 4 and the first column 2, which is a structural column, is a rigid joint. Further, the joint between the beam 4 and the second column 3 is a rigid joint. As a result, the horizontal force can be transmitted to the second pillar 3. In FIG. 2A, the beam 4 capable of transmitting the horizontal force to the column is shown by a solid line. On the other hand, the beam 6 that does not transmit the horizontal force is shown by a broken line. FIG. 2B shows a frame structure 100 in a state where the beam 6 is omitted in order to show only a member that functions as a seismic element. Further, as shown in FIG. 1, the beam 4 is provided at a position corresponding to the floor of the first floor, the boundary position of each floor, and the ceiling of the top floor so as to define the floor height of each floor.

Next, the arrangement of the first pillar 2, the second pillar 3, and the beam 4 will be described. However, the configurations shown in FIGS. 1 and 2 are merely examples and can be changed as appropriate.

The frame structure 100 according to the present embodiment includes a tube frame 15 configured to surround the central axis when viewed from above by the first pillar 2, the second pillar 3, and the beam 4. That is, a tube frame 15 in which column-beam frames, which are earthquake-resistant elements, are arranged on four outer peripheral surfaces is configured. In particular, the frame structure 100 according to the present embodiment has a double tube frame structure in which the tube frame 20 is further provided on the inner peripheral side of the tube frame 15 on the outermost peripheral side.

First, the configuration of the tube frame 15 on the outermost peripheral side will be described. The tube frame 15 has nine columns 5 in the X-axis direction and nine columns 5 in the Y-axis direction. Here, it is assumed that pillars 5A ₁ , 5A ₂ , 5A ₃ , 5A ₄ , 5A ₅ , 5A ₆ , 5A ₇ , 5A ₈ , 5A ₉ are provided toward the positive side in the X-axis direction. Each column 5 is connected by a beam 4 to adjacent columns 5 in the X-axis direction. Of such pillars 5, pillars 5A ₁ , 5A ₃ , 5A ₅ , 5A ₇ , 5A ₉ are composed of the first pillar 2, and pillars 5A ₂ , 5A ₄ , 5A ₆ , 5A ₈ are the second pillars. It is composed of 3. In this way, the second pillar 3 is arranged between the first pillars 2. Further, it is assumed that pillars 5B ₁ , 5B ₂ , 5B ₃ , 5B ₄ , 5B ₅ , 5B ₆ , 5B ₇ , 5B ₈ , 5B ₉ are provided toward the positive side in the Y-axis direction. Each column 5 is connected by a beam 4 to adjacent columns 5 in the Y-axis direction. Of such pillars 5, pillars 5B ₁ , 5B ₂ , 5B ₄ , 5B ₆ , 5B ₈ , 5B ₉ are composed of the first pillar 2, and pillars 5A ₃ , 5A ₅ , 5A ₇ are the second pillars. It is composed of 3. In this way, the second pillar 3 is arranged between the first pillars 2. However, the corner pillar 5A ₁ is the same pillar 5 as any of the pillars 5B ₁ , 5B ₉ , and the corner pillar 5A ₉ is the same pillar as any of the pillars 5B ₁ , 5B ₉ .

Next, the configuration of the tube frame 20 provided on the inner peripheral side of one step of the tube frame 15 will be described. The tube frame 20 has seven pillars 5 in the X-axis direction and seven pillars 5 in the Y-axis direction. The pillars 5 arranged in the X-axis direction of the tube frame 20 are arranged at the same positions as the pillars 5A ₂ , 5A ₃ , 5A ₄ , 5A ₅ , 5A ₆ , 5A ₇ , 5A ₈ of the tube frame 15 in the X-axis direction. Has been done. Each column 5 is connected by a beam 4 to adjacent columns 5 in the X-axis direction. Of such pillars 5, pillars 5A ₂ , 5A ₃ , 5A ₅ , 5A ₇ , 5A ₈ are composed of the first pillar 2, and pillars 5A ₄ , 5A ₆ are composed of the second pillar 3. In this way, the second pillar 3 is arranged between the first pillars 2. The pillars 5 arranged in the Y-axis direction of the tube frame 20 are located at the same positions as the pillars 5B ₂ , 5B ₃ , 5B ₄ , 5B ₅ , 5B ₆ , 5B ₇ , 5B ₈ of the tube frame 15 in the Y-axis direction. Is located in. Each column 5 is connected by a beam 4 to adjacent columns 5 in the Y-axis direction. Of such pillars 5, pillars 5B ₂ , 5B ₄ , 5B ₆ , 5B ₈ are composed of the first pillar 2, and pillars 5B ₃ , 5B ₅ , 5B ₇ are composed of the second pillar 3. In this way, the second pillar 3 is arranged between the first pillars 2. However, the pillar 5A ₂ at the corner is the same pillar 5 as any of the pillars 5B ₂ and 5B ₈ , and the pillar 5A _{8 at the} corner is the same pillar as any of the pillars 5B ₂ and 5B ₈ .

As shown in FIG. 1, among the plurality of second pillars 3, some of the second pillars 3 may be provided only on the lower layer side of the building 1 and may be omitted from the upper layer side. For example, as shown in FIG. 1A, a part of the upper layer side of the second pillar 3 arranged at the position corresponding to the pillar 5B ₅ near the center position is omitted (indicated by a broken line). You may. As shown in FIG. 1B, a part of the upper layer side of the second pillar 3 arranged at the position corresponding to the pillars 5A ₄ and 5A ₆ near the central position may be omitted. However, the position at which the upper layer side of the second pillar 3 is omitted is not particularly limited, and the layer from which the second pillar 3 is omitted is not particularly limited.

As shown in FIG. 2B, a wide space in which the beam 4 is not provided is secured in the region on the inner peripheral side of the tube frame 20 on the inner peripheral side. A plurality of first pillars 2 are provided in the space on the central side. Specifically, the first pillar 2 is located at a position corresponding to the pillars 5B ₄ , 5B ₆ in the Y-axis direction and corresponding to the pillars 5A ₃ , 5A ₄ , 5A ₅ , 5A ₆ , 5A ₇ in the X-axis direction. Is provided. However, how the first pillar 2 is arranged in the space on the central side is not particularly limited.

Next, the dimensional relationship between columns and beams will be described. When the span between the first columns 2 is L and the floor height determined by the distance between the beams 4 in the vertical direction is H, the span L is 4 times or less of the floor height H and 20 m or less. preferable. The value is derived by considering the member angle of the beam 4, the axial force of the column 5, the amount of steel frame of the upper frame (that is, the frame by the beam and the column), the horizontal rigidity of the upper frame, and the like. More preferably, the span L may be three times or less the floor height H. In the present embodiment, the span L between the first pillars 2 indicates the distance in the horizontal direction between the seismic isolation device 10 and the seismic isolation device 10 sandwiching the second pillar 3. The distance between the seismic isolation device 10 and the seismic isolation device 10 here indicates the distance between the seismic isolation devices 10 adjacent to each other in the X-axis direction or the seismic isolation devices 10 adjacent to each other in the Y-axis direction. It is not the distance between the seismic isolation devices 10 adjacent to each other in the diagonal direction with respect to the X-axis direction and the Y-axis direction. Since the frame structure 100 has a plurality of first columns 2 and a seismic isolation device 10, the span L varies depending on the position of the frame structure 100, but all spans set in the frame structure 100. It is preferable that L satisfies the above-mentioned relationship. However, for a predetermined reason, some spans L in the frame structure 100 may not satisfy the above relationship.

Next, the action / effect of the building frame structure 100 according to the embodiment of the present invention will be described.

First, for comparison, the frame structure 200 according to the comparative example will be described with reference to FIGS. 6 and 7. For example, as shown in FIG. 6, in the frame structure 200, all the columns correspond to the structural columns, and the seismic isolation device 10 is provided at the lower part. In this case, as shown in FIG. 7A, each structural column (in the example of FIG. 5, the column corresponding to the “second column 3” also functions as a structural column) bears a long-term axial force. At the time of an earthquake, as shown in FIG. 7B, each structural column bears a horizontal force. In this way, when the seismic isolation devices 10 are provided on all the structural columns, the long-term axial force acting on each seismic isolation device 10 is reduced, so that the compressive force applied to the laminated rubber of the seismic isolation device 10 is increased. It may be insufficient. In such a case, the tensile force acting on the seismic isolation device 10 at the time of an earthquake may increase. Therefore, in order to suppress such tension, it is necessary to take measures such as providing a counter weight on the beam near the seismic isolation device 10. As a result, there is a problem that the cost increases.

In addition, in order to improve the seismic isolation effect of the building, it is necessary to increase the ratio of the horizontal rigidity of the seismic isolation layer (the part where the seismic isolation device is installed) and the superstructure (the frame composed of beams and columns). However, in the past, the seismic isolation effect was improved by lowering the horizontal rigidity of the seismic isolation layer by providing a sliding bearing with a small frictional force on the seismic isolation layer. Therefore, from this point as well, there is a problem that the cost increases. From the above, it has been required to ensure seismic isolation performance while simplifying the seismic isolation structure.

On the other hand, according to the frame structure 100 according to the present embodiment, the seismic isolation device 10 is provided at the lower part of the first pillar 2, but is not provided at the lower part of the second pillar 3. , Omitted. According to such a structure, a long-term axial force acts on the first column 2 and horizontal rigidity is ensured. On the other hand, since the second pillar 3 is not provided with the seismic isolation device 10 at the lower part, the long-term axial force is applied to the first pillar 2 with almost no burden on the long-term axial force. .. As a result, a compressive force acts on the seismic isolation device 10, so that the tensile force generated in the seismic isolation device 10 below the first pillar 2 during an earthquake can be reduced. On the other hand, the joint between the second column 3 and the beam 4 is a rigid joint. With such a structure, a horizontal force can be transmitted to the second pillar 3. Therefore, the second column 3 can support the horizontal force, and the horizontal rigidity of the frame structure 100 can be increased. In this way, since the second column 3 can support the horizontal force, the horizontal rigidity of the frame structure 100 can be ensured by the second column 3 together with the first column 2. Even if the seismic isolation device 10 is omitted from the lower part of the second pillar 3, the building space is provided with high flexibility and the seismic isolation structure is provided with extremely small shaking during an earthquake. From the above, seismic isolation performance can be ensured.

For example, as shown in FIG. 5A, the seismic isolation device 10 is not provided in the lower part of the second pillar 3, and the long-term axial force does not substantially act on the second pillar 3. On the other hand, if the second column 3 is a structural column, the long-term axial force that originally acts (in FIG. 7A, the long-term axis that acts on the structural column at the position corresponding to the "second column 3"). The force) acts on the adjacent first pillar 2. Then, in addition to the long-term axial force acting on the structural column shown in FIG. 7A, the long-term axial force corresponding to the column in which the seismic isolation device 10 is omitted acts additionally on the first column 2. As a result, a longer-term axial force acts on the seismic isolation device 10 than on the seismic isolation device 10 of the frame structure 200 according to the comparative example, and a large compressive force acts on the laminated rubber of the seismic isolation device 10. Therefore, the tensile force of the seismic isolation device 10 at the time of an earthquake is reduced. On the other hand, as shown in FIG. 5B, a sufficient horizontal force acts on the second column 3 as in the second column 3 of the frame structure 200 according to the comparative example. Therefore, even if the seismic isolation device 10 is omitted, the second column 3 can sufficiently secure the horizontal rigidity of the frame structure 100.

Further, in the building frame structure 100 according to the present embodiment, the tube frame 15, which is configured to surround the central axis when viewed from above by the first pillar 2, the second pillar 3, and the beam 4. 20 is provided. With such a configuration, the horizontal rigidity of the frame structure 100 can be increased, so that seismic isolation can be effectively performed even when the number of seismic isolation devices 10 is reduced.

Further, in the building frame structure 100 according to the present embodiment, the second pillar 3 is composed of members having a strong axis direction and a weak axis direction. The load of the long-term axial force on the second column 3 is extremely small, and only the horizontal rigidity needs to be secured. In this way, the amount of steel frame in the building can be reduced by setting the unnecessary strength direction to the weak axis direction.

Further, in the building frame structure 100 according to the present embodiment, the first pillar 2 is composed of members having a strong axis direction and a weak axis direction. As for the first column 2, the amount of steel frame of the building can be reduced by setting the direction in which the strength is unnecessary to be the weak axis direction.

Further, in the building frame structure 100 according to the present embodiment, the second pillar 3 is provided on the lower layer side of the building and is omitted from the upper layer side. Since the horizontal rigidity to be secured in the upper layer may be small, the second column 3 can be omitted. Therefore, by omitting the second pillar 3 in the upper layer, the space in the upper layer can be widely used.

The present invention is not limited to the above-described embodiment.

For example, the arrangement and number of the second pillars are not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the present invention. For example, in the above-described embodiment, one second pillar is provided between the first pillar and the first pillar, but a plurality of second pillars may be provided.

For example, as shown in FIG. 3, in order to utilize the central space on the inner peripheral side of the tube frame 20 on the inner peripheral side more widely, the number of the first pillars in the central space may be reduced. Further, the beam 6 may not be provided in the central space, but may be provided only between the tube frame 15 and the tube frame 20.

Further, as shown in FIG. 4A, the brace 30 may be arranged in each section composed of each column and beam. The brace 30 is arranged at the lower end of the second column in the lowermost layer so that the tensile force on the seismic isolation device due to the fluctuating axial force of the seismic input is less likely to occur. Further, as shown in FIG. 4B, an intermediate beam 31 may be provided at an intermediate position in the vertical direction of the floor height to increase the horizontal rigidity.

2 ... 1st column, 3 ... 2nd column, 4 ... beam, 10 ... seismic isolation device, 15 ... tube frame, 20 ... tube frame, 100 ... frame structure.

Claims (3)

The tube frame structure of the building
A plurality of first pillars extending in the vertical direction,
A plurality of second pillars extending in the vertical direction between the first pillars,
With multiple beams extending horizontally,
It is equipped with a seismic isolation device provided at the bottom of the building.
The seismic isolation device is provided in the lower part of the first pillar, and is not provided in the lower part of the second pillar.
Junction between the first pillar and the second pillar and the beam, Ri rigid connections der,
The first column, the second column, and the beam form a tube frame configured to surround the central axis when viewed from above.
When the span between the first columns is L and the floor height determined by the distance between the beams in the vertical direction is H, the span L is 4 times or less of the floor height H and 20 m or less.
A frame structure of a building in which at least a part of the second column is omitted without reaching the uppermost beam, so that the upper layer side of the building has lower horizontal rigidity than the lower layer side . The frame structure of a building according to claim 1, wherein the second pillar is composed of members having a strong axial direction and a weak axial direction. The frame structure of a building according to claim 1 or 2, wherein the first pillar is composed of members having a strong axial direction and a weak axial direction.

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