Seismic isolation structure

Abstract

To enable reduction of facilities required for wind countermeasures, and furthermore to enable exhibiting of an excellent base isolation effect thereby enabling reduction of seismic force.SOLUTION: A base-isolated structure comprises: a low-level architecture 11; an upper architecture 12 provided above the low-level architecture; a core portion 13 which has structure integrally connected to each of the low-level architecture and the upper architecture; an outside architecture 14 which is arranged outside the core portion and is separated from the core portion and the low-level architecture; and a lower side base isolation layer 21 for connecting the outside architecture and the low-level architecture, wherein the core portion, the low layer architecture, the upper architecture and the outside architecture have different structure types, and a structure switching story 30 is provided between the upper portion of the outside architecture and the lower portion of the upper architecture.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Conventionally, for example, in a 200m-class super-high-rise seismically isolated structure that stacks residential and office buildings, when the height of the upper part of the seismic isolation layer exceeds 150m, wind loads become larger than seismic forces depending on the aspect ratio of the building, and therefore an intermediate-story seismic isolation structure such as that shown in Patent Document 1 has been adopted. This intermediate-story seismic isolation structure is provided with a core-side seismic isolation layer that isolates the lower part of the core section that is integrated with the upper frame on the intermediate seismic isolation layer, and the lower part of the outer frame that is placed on the periphery of the core section is also supported by the core-side seismic isolation layer, and the core-side seismic isolation layer deforms significantly to efficiently absorb energy and achieve a high response reduction effect. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-218841 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when adopting a conventional mid-story seismic isolation structure, it is known to place wind lock dampers, steel dampers, wind-resistant shear pins, etc. between the perimeter frame and the core as a countermeasure against wind loads. For example, with a wind lock damper, the lock is turned off during normal times to function as a seismic isolation damper, and when winds are strong, the damper function is locked to lock it, improving the habitability of the building during strong winds. As such, buildings with conventional mid-story seismic isolation structures have had the problem of requiring countermeasures against wind loads, resulting in excessively large structures.

[0005] In addition, in conventional mid-story seismic isolation structures, the suspension elevator system or the seismic isolation elevator system is commonly used for elevators that penetrate the seismic isolation layer. When the suspension elevator system is used in mid-story seismic isolation structures, the length of the suspension frame that houses the elevator extending downward from the seismic isolation layer in the low-rise frame increases. This means that it is structurally difficult to ensure sufficient clearance to accommodate horizontal deformation of the elevator in a plan view. Therefore, the seismic isolation elevator system is often adopted when the seismic isolation layer is located high and the length of the suspension elevator frame is long. On the other hand, the seismic isolation elevator system has two limitations: a normal deformation limit set to prevent the elevator from stopping due to deformation caused by annual recurrence winds or frequent earthquakes of seismic intensity 3 or so, and an earthquake deformation limit set based on the elevator rail's compliance limit and repair limit. Because of these limitations on the elevator and the structural measures of stiffening the seismic isolation layer to minimize building deformation, it is difficult to maximize the seismic isolation effect and reduce seismic force, leaving room for improvement. Furthermore, when the height of the top of the seismic isolation layer exceeds 150m, the locking mechanism of the seismic isolation layer becomes excessive, resulting in an increase in the rigidity of the seismic isolation layer and a loss of its earthquake mitigation effect.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a seismic isolation structure that can reduce the equipment required for wind countermeasures, and that can exert an excellent seismic isolation effect and reduce seismic forces. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the seismic isolation structure of the present invention comprises a low-rise frame, an upper frame provided above the low-rise frame, a core section structurally connected to each of the low-rise frame and the upper frame, an outer frame arranged outside the core section and separated from the core section and the low-rise frame, and a lower seismic isolation layer connecting the outer frame and the low-rise frame, wherein the core section, the low-rise frame, and the upper frame are of different structural types from the outer frame, and a structural switching floor is provided between the upper part of the outer frame and the lower part of the upper frame.

[0008] In the seismic isolation structure of the present invention, only the outer frame placed outside the core is seismically isolated, and the core is integrally connected to the upper frame and the low-rise frame. In other words, the core connected to the low-rise frame bears part of the external wind force and transmits it to the low-rise frame without going through the seismic isolation layer, which reduces the external wind force acting on the lower seismic isolation layer and reduces the equipment required to deal with the wind load on the lower seismic isolation layer installed between the outer frame and the core.

[0009] Furthermore, according to the present invention, since the core section is structurally connected to both the low-rise frame and the upper frame, there is no need to set limits on elevator deformation, and conventional structural measures for elevators to harden the seismic isolation layer and minimize building deformation (for example, structural measures to prevent elevators that penetrate the upper and low-rise frames from stopping due to annual recurrence winds or frequent earthquakes of seismic intensity 3 or so) are no longer necessary, making it possible to maximize the seismic isolation effect.As a result, a seismic isolation structure can be realized in buildings where the height of the upper part of the seismic isolation layer exceeds 200 m, for example, and seismic force can be reduced. Furthermore, the present invention allows for the coexistence of different structural types of outer and lower-rise structures on a single floor. For example, the outer structure can be made of reinforced concrete, like a residential building, while the core can be made of steel.

[0010] Furthermore, according to the present invention, the upper part of the outer frame is structurally connected to the lower part of the upper frame via the structural switching floor, eliminating the need for a seismic isolation layer between the outer frame and the upper frame, thereby reducing the number of seismic isolation devices that need to be installed.

[0011] In addition, the seismic isolation structure of the present invention may be configured such that the upper part of the outer frame is structurally connected to the lower part of the upper frame via the structural switching floor, and only the lower seismic isolation layer is provided between the lower part of the outer frame and the upper part of the low-rise frame.

[0012] By configuring it in this way, the structure of the seismic isolation structure can be simplified, and the number of seismic isolation devices that need to be installed can be reduced compared to a structure with multiple seismic isolation layers.

[0013] In addition, in the seismic isolation structure according to the present invention, the core portion, the low-rise frame, and the upper frame may be made of steel, and the outer frame may be made of reinforced concrete.

[0014] In addition, the seismic isolation structure of the present invention may have a clearance between the core portion and the outer frame that allows relative displacement in the horizontal direction, and may have a movable connecting portion that connects the core portion and the outer frame so that they can move relative to each other in the horizontal direction.

[0015] In the seismic isolation structure according to the present invention, the outer frame may be provided around the entire periphery of the core portion.

[0016] By configuring it in this way, the outer frame is arranged to surround the core part, which allows for greater freedom in architectural planning. [Effects of the Invention]

[0017] According to the seismic isolation structure of the present invention, it is possible to reduce the amount of equipment required for wind countermeasures, and it is possible to achieve excellent seismic isolation effects and reduce seismic forces. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a vertical cross-sectional view showing a seismic isolation structure according to the present embodiment. [Figure 2] 1, (a) is a cross-sectional view taken along line II in FIG. 1, showing a horizontal cross-section of the upper frame, (b) is a cross-sectional view taken along line II-II in FIG. 1, showing a horizontal cross-section of the core and outer frame, and (c) is a cross-sectional view taken along line III-III in FIG. 1, showing a horizontal cross-section of the low-rise frame. [Figure 3] This is a longitudinal cross-sectional view (Model B) of the seismic isolation structure used in the earthquake response analysis. [Figure 4] 10 is a graph showing the maximum acceleration of Model A and Model B in earthquake response analysis. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, a seismic isolation structure according to an embodiment of the present invention will be described with reference to the drawings.

[0020] As shown in Figure 1, the seismic isolation structure 100 of this embodiment is applied to a building that is over 250 m high, for example, with residential and office buildings stacked on top of each other, and whose height above the seismic isolation layer (in this embodiment, the lower seismic isolation layer 21 described later) is over 200 m high.

[0021] The base-isolated structure 100 includes a low-rise frame 11, an upper frame 12, a core 13, a perimeter frame 14 (outer frame), and a structural switching floor 30. The base-isolated structure 100 has a rectangular shape in plan view. Here, the symbol GL in Fig. 1 indicates ground level.

[0022] The low-rise frame 11 is a low-rise floor portion including an underground portion installed from the basement to the ground, and is installed on a foundation. The upper frame 12 is provided above the low-rise frame 11. In this embodiment, for example, office space is arranged on the upper frame 12, and for example, commercial facilities and offices are arranged on the low-rise frame 11.

[0023] The core section 13 is disposed in the center of the building in plan view, between the low-rise frame 11 and the upper frame 12, and is structurally connected to each of them. That is, the core section 13, the low-rise frame 11, and the upper frame 12 are made of steel and have an integrated structure. As shown in Figure 2(b), the core section 13 has a rectangular shape in plan view.

[0024] As shown in Figures 2(a) to 2(c), the core section 13 is provided with an elevator 15 that is connected to the upper frame 12 and the low-rise frame 11. The elevator 15 passes through the core section 13 in the vertical direction and extends continuously inside the low-rise frame 11 and the upper frame 12. The elevator 15 is provided in a shaft 17. In addition to the elevator 15, components such as water supply and drainage equipment, air conditioning equipment, and electrical equipment are also arranged in the shaft 17. The planar shape of the core portion 13 is not limited to a rectangular shape as in this embodiment, and other shapes such as a square shape or a circle shape may also be adopted.

[0025] The outer periphery frame 14 is arranged to surround the outer periphery of the core section 13, and is separated from the core section 13 and the low-rise frame 11. In other words, the outer periphery frame 14 is arranged to be spaced apart from the core section 13 in the horizontal direction, and is arranged to be spaced apart from the low-rise frame 11 in the vertical direction.

[0026] The outer perimeter frame 14 is provided around the entire perimeter of the core section 13. The outer perimeter frame 14 is made of reinforced concrete, and houses serving as living spaces are arranged therein. In other words, the outer perimeter frame 14 is of a different structural type from the core section 13, the low-rise frame 11, and the upper frame 12, which are made of steel.

[0027] A clearance C that allows relative displacement in the horizontal direction is provided between the core section 13 and the outer peripheral frame 14. A movable connecting section 16 that connects the core section 13 and the outer peripheral frame 14 so that they can move relatively in the horizontal direction is provided between the core section 13 and the outer peripheral frame 14. As the movable connecting section 16, for example, an expansion joint or the like can be used. As the core section 13 and the outer peripheral frame 14 have different vibration characteristics, clearance C is secured around the entire circumference between the core section 13 and the outer peripheral frame 14, allowing the core section 13 and the outer peripheral frame 14 to vibrate independently during an earthquake.

[0028] A structural switching floor 30 is provided between the lower part 12a of the upper frame 12 and the upper part 14a of the periphery frame 14. The upper part 14a of the periphery frame 14 and the structural switching floor 30 are structurally connected. The lower part 12a of the upper frame 12 and the structural switching floor 30 are structurally connected. In other words, the upper frame 12 and the periphery frame 14 are structurally integrated via the structural switching floor 30. In this embodiment, the periphery frame 14 is made of reinforced concrete, the upper frame 12 is made of steel frame, and at the structural switching floor 30, the structural type is switched from reinforced concrete to steel frame.

[0029] The seismic isolation structure 100 is provided with a lower seismic isolation layer 21 that connects the perimeter frame 14 and the low-rise frame 11, and a structural switching floor 30 that connects the perimeter frame 14 and the upper frame 12. The lower seismic isolation layer 21 is provided with a plurality of seismic isolation devices 23. The seismic isolation devices 23 can be, for example, laminated rubber, sliding bearings, linear sliders, or a combination of two or more. The lower seismic isolation layer 21 has two seismic isolation devices 23 arranged on the inner side that is located on the core side when viewed from the side, and on the outer side. The height of the lower seismic isolation layer 21 can be set as desired according to conditions such as the type and shape of the seismic isolation devices 23 used.

[0030] Next, the operation of the seismic isolation structure 100 described above will be explained in detail with reference to the drawings. As shown in Figure 1, in the seismic isolation structure 100 of this embodiment, the perimeter frame 14 located on the outer periphery of the core section 13 has a seismic isolation structure, and the core section 13 is integrally connected to the upper frame 12 and the low-rise frame 11. In other words, the core section 13 connected to the low-rise frame 11 bears part of the external wind force and transmits the external wind force to the low-rise frame 11 without going through the seismic isolation layer, so the external wind force acting on the lower seismic isolation layer 21 can be reduced and the equipment required to deal with the wind load on the lower seismic isolation layer 21, which is provided between the perimeter frame 14 and the core section 13, can be reduced.

[0031] Furthermore, according to this embodiment, since the core 13 is structurally integrally connected to each of the low-rise frame 11 and the upper frame 12, there is no need to set deformation limits for the elevator 15, and conventional structural measures for the elevator 15 to harden the seismic isolation layer and minimize deformation of the building (for example, structural measures to accompany the stoppage of the elevator 15 that penetrates the upper frame 12 and the low-rise frame 11 due to one-year recurrence winds or frequent earthquakes of seismic intensity 3 or so) are no longer necessary, making it possible to maximize the seismic isolation effect. Therefore, in this embodiment, a seismic isolation structure can be realized in a building where the height above the lower seismic isolation layer 21 exceeds, for example, 200 m, and seismic force can be reduced.

[0032] Furthermore, in this embodiment, it is easy to achieve coexistence of different structural types of frames on a floor plan between the perimeter frame 14 and the low-rise frame 11. For example, the perimeter frame 14 can be a residential structure made of reinforced concrete, and the core section 13 can be made of steel.

[0033] Furthermore, in the base-isolated structure 100 according to this embodiment, the upper part of the perimeter frame 14 is connected to the lower part of the upper frame 12 via the structural switching floor 30. In this embodiment, a sufficient height can be ensured from the lower base isolation layer 21 to the structural switching floor 30, allowing the core portion 13 to deform flexibly. Therefore, although only the perimeter frame 14 is of a base-isolated structure, the entire base-isolated structure 100 becomes a frame with deformation performance equivalent to that of a base-isolated building, without impeding the deformation of the lower base isolation layer 21 of the perimeter frame 14.

[0034] In addition, in this embodiment, the outer periphery frame 14 is arranged so as to surround the core portion 13, which allows for greater freedom in architectural planning.

[0035] As described above, the base-isolated structure 100 according to this embodiment can reduce the amount of equipment required for wind countermeasures, and can achieve excellent base isolation effects to reduce seismic forces.

[0036] (Earthquake response analysis) Next, an earthquake response analysis performed to verify the effects of the base-isolated structure 100 according to the above-described embodiment will be described.

[0037] This earthquake response analysis used a bending-shear bar model created from an incremental elasto-plastic analysis of a member-based three-dimensional frame model. The input earthquake motion was a public announcement wave (Kobe phase) input to the support at the base of the foundation. The models used in the analysis were Model B shown in Figure 3 and an analytical model (Model A) equivalent to the seismic isolation structure 100 shown in Figure 1. Model B is a model in which an upper seismic isolation layer 22 is installed at the structural switching floor 30 of Model A. In other words, in Model B, the perimeter frame 14 is structurally separated from the low-rise frame 11, upper frame 12, and core 13. In Model B, the perimeter frame 14 and low-rise frame 11 are connected via the lower seismic isolation layer 21, and the perimeter frame 14 and upper frame 12 are connected via the upper seismic isolation layer 22.

[0038] Figure 4 shows the height direction distribution of the maximum response acceleration for each floor obtained from the earthquake response analysis. As shown in Figure 4, it can be confirmed that there is almost no difference between Model A and Model B in the maximum acceleration at the top and the maximum acceleration of the base part (low-rise frame 11). Regarding the living space (periphery frame 14), both Model A and Model B show that the maximum acceleration is approximately 150 (cm / sec) on all floors even during a major earthquake. 2 ) or less, which shows that a high level of response control is possible.

[0039] As in the seismic isolation structure 100 of this embodiment, a predetermined response reduction effect can be obtained even when the seismic isolation layer is not provided in the upper floors. As a result, for the above-mentioned Model A and Model B, the degree of freedom in design can be increased by comprehensively selecting the structure taking into account compatibility with the architectural plan.

[0040] Although the embodiments of the seismic isolation structure according to the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified as appropriate within the scope of the invention.

[0041] For example, the height, area, planar shape, dimensions of the clearance C, and other configurations of each frame of the seismic isolation structure 100 of the above-described embodiment can be set as appropriate.

[0042] In addition, in this embodiment, a movable connecting portion 16 is provided to connect the core portion 13 and the outer peripheral frame 14 so that they can move relative to each other in the horizontal direction in the clearance C provided between the core portion 13 and the outer peripheral frame 14, but this is not limited to providing a movable connecting portion 16, and the configuration of the movable connecting portion 16 can be set as desired.

[0043] In addition, in this embodiment, an example is adopted in which the core section 13, low-rise structure 11, and upper structure 12 are made of steel, and the outer perimeter structure 14 is made of reinforced concrete, and each structure type is different, but the structure type is not limited to this.

[0044] Furthermore, in this embodiment, the outer peripheral frame 14 is provided around the entire periphery of the core portion 13, but this is not limited to the entire periphery. That is, the outer peripheral frame 14, which is an example of an outer frame, may be provided on a portion of the periphery of the core portion 13 in the circumferential direction, or may be divided in the circumferential direction. Furthermore, the position of the outer peripheral frame relative to the core portion is not limited to the outer frame being arranged in the circumferential direction on the outer periphery of the core portion 13 as in the above embodiment. That is, the outer frame only needs to be arranged outside the core portion so as to face the core portion in the horizontal direction. For example, a structure in which the core portion is arranged on one side in the left-right direction and the outer frame is arranged on the other side in the left-right direction, with the core portion and the outer frame arranged side by side, may also be used.

[0045] In addition, the components in the above-described embodiments can be replaced with well-known components as appropriate, without departing from the spirit of the present invention.

[0046] The Sustainable Development Goals (SDGs) are 17 international goals adopted at the United Nations Summit in September 2015. The welding device according to this embodiment can contribute to achieving one of the 17 SDGs, for example, goal 11, "Sustainable cities and communities." [Explanation of symbols]

[0047] 100 Seismic isolation structures 11 Low-rise structure 12 Upper frame 13 Core 14 Perimeter frame (outer frame) 15 Elevator 16 Movable connection part 21 Lower seismic isolation layer 23 Seismic isolation device 30 structural switching floors C Clearance

Claims

1. A low-rise structure, an upper frame provided above the low-rise frame; a core portion structurally integrally connected to each of the low-rise frame and the upper frame; an outer frame disposed outside the core portion and separated from the core portion and the low-rise frame; a lower seismic isolation layer connecting the outer frame and the low-rise frame; Equipped with The core portion, the low-rise frame, and the upper frame are of different structural types from the outer frame, A structural switching floor is provided between the upper part of the outer frame and the lower part of the upper frame, A seismic isolation structure characterized in that the upper part of the outer frame and the structural switching floor are structurally connected, and the lower part of the upper frame and the structural switching floor are structurally connected.

2. A seismic isolation structure as described in Claim 1, in which only the lower seismic isolation layer is provided between the lower part of the outer frame and the upper part of the low-rise frame.

3. The core portion, the low-rise frame, and the upper frame are made of steel, The seismic isolation structure according to claim 1, wherein the outer frame is made of reinforced concrete.

4. a clearance is provided between the core portion and the outer frame to allow relative displacement in a horizontal direction; 2. The seismic isolation structure according to claim 1, further comprising a movable connecting portion that connects the core portion and the outer frame so that they can move relative to each other in the horizontal direction.

5. The seismic isolation structure according to claim 1 , wherein the outer frame is provided around the entire periphery of the core portion.

6. A low-rise structure, an upper frame provided above the low-rise frame; a core portion structurally integrally connected to each of the low-rise frame and the upper frame; an outer frame disposed outside the core portion and separated from the core portion and the low-rise frame; a lower seismic isolation layer connecting the outer frame and the low-rise frame; Equipped with The core portion, the low-rise frame, and the upper frame are of different structural types from the outer frame, A structural switching floor is provided between the upper part of the outer frame and the lower part of the upper frame, The core portion, the low-rise frame, and the upper frame are made of steel, The outer frame is a seismic isolation structure made of reinforced concrete.

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