JP2017223088A - Building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a building formable as a structure strong against an earthquake, even when improving a degree of freedom of a layout.SOLUTION: In a building 10, a base-isolation layer 11 is provided underground. This building 10 comprises a liniac chamber constituted of a radiation shielding structure 30 in an upper layer floor of a second story to the base-isolation layer 11. The radiation shielding structure 30 comprises a shielding floor, the shielding ceiling and a shielding wall. A radiation shielding member 35 having a thickness of about 1 m-about 3 m and constituted of concrete 31 of burying a reinforcement and constituted of an iron plate, is buried in the shielding floor, the shielding ceiling and the shielding wall. Concrete 25 of burying the reinforcement is placed in an outer peripheral part of a column 21 for installing the concrete 31 of the radiation shielding structure 30 in a lower story than the radiation shielding structure 30.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a building including a seismic isolation layer and a radiation shielding structure.

  A radiation therapy device (linac) may be used to treat diseases such as cancer and to relieve pain. In this radiotherapy apparatus, high-activity radiation is irradiated to a lesion. For this reason, the room in which the radiation therapy apparatus is installed is configured by a radiation shielding structure so that radiation does not leak outside (see, for example, Patent Document 1). The radiation shielding structure described in Patent Literature 1 includes a shielding side wall portion, a shielding floor portion, and a shielding ceiling portion. And the shielding ceiling part has the intermediate | middle layer comprised with a material with a low average radiation attenuation factor between the 1st concrete layer by the side of a radiation generator, and the 2nd outer concrete layer.

Japanese Patent Laid-Open No. 2006-57188

  Conventionally, a building provided with a radiation shielding structure is configured with an earthquake resistant structure. And since a radiation shielding structure uses a shielding structure, it becomes heavier than other floor structures. Therefore, the radiation shielding structure is usually installed in the basement or the first floor (lowermost layer) of the building to support the weight. This is because if a shielding structure is installed on the upper floor, in the case of an earthquake-resistant structure, there is a possibility that structural members (columns) directly under the shielding structure may be damaged due to the occurrence of an unexpected large earthquake and affect the building by. Thus, when installing a radiation shielding structure in the basement or the first floor of a building, the degree of freedom of layout in the building may be lowered.

  This invention is made | formed in view of the said subject, The objective is to provide the building which can be made into a structure strong against an earthquake, ensuring the freedom degree of a layout.

  -The building which solves the said subject WHEREIN: In the building provided with the seismic isolation layer and the radiation shielding structure, a radiation shielding structure is arrange | positioned on the installation floor of an upper floor rather than the floor immediately above the said seismic isolation layer. Thereby, even if the freedom degree of a layout is improved, it can be set as a structure strong against an earthquake.

  -In the said building, it is preferable to arrange | position the said radiation shielding structure to the upper floor of the 2nd hierarchy with respect to the said seismic isolation layer. Thereby, the maximum response absolute acceleration by the earthquake in the installation floor of a radiation shielding structure can be made small. In addition, the maximum response absolute acceleration of the entire building can be reduced.

  -In the said building, it is preferable that the vibration damper is provided in the hierarchy between the hierarchy in which the said radiation shielding structure was provided, and the said seismic isolation layer. Thereby, the whole building can be efficiently damped against vibration such as an earthquake.

  -In the said building, It is preferable that the column of the steel reinforced concrete structure is provided in the hierarchy between the hierarchy in which the said radiation shielding structure was provided, and the said seismic isolation layer. Thereby, while supporting performance by the bearing pressure of concrete can be expected, the fixing degree of the column directly under the radiation shielding structure can be improved. Therefore, a heavy radiation shielding structure can be more firmly supported against axial force, shearing and bending.

  According to the present invention, the degree of freedom in layout can be improved and a structure that is resistant to earthquakes can be obtained.

The cross-sectional schematic diagram explaining the internal structure of the building in this embodiment. Sectional drawing of the principal part of the building in this embodiment. It is explanatory drawing of the information used for the simulation analysis in this embodiment, (a) is a building which has a radiation shielding structure in the hierarchy one layer from right above the base isolation layer of this embodiment, (b) is a base isolation layer. A comparative building with a radiation shielding structure directly above is shown. It is a figure explaining the simulation analysis result in this embodiment, (a) shows the maximum response absolute acceleration, (b) shows the maximum layer shear force. The cross-sectional schematic diagram explaining the internal structure of the building in the example of a change.

Hereinafter, the embodiment which actualized the building is described using FIGS.
Here, as shown in FIG. 1, an 8-story building 10 having a radiation shielding structure will be described. The building 10 is a medical facility such as a hospital, and includes a linac room configured by a radiation shielding structure 30.

  The building 10 is provided with a base isolation layer 11 in the basement. The seismic isolation layer 11 is provided between an upper structure installed on the ground and a lower structure such as a foundation or an underground frame. And it arrange | positions so that the directly upper floor of the seismic isolation layer 11 may become the ground floor. In the seismic isolation layer 11, a plurality of seismic isolation devices 11a are installed at intervals. A laminated rubber isolator or the like is used as the seismic isolation device 11a.

  The superstructure of the building 10 is constructed of a steel frame having steel columns 21 and beams 22. A radiation shielding structure 30 is provided on the second floor of the building 10 (two floors above the seismic isolation layer 11). The radiation shielding structure 30 is arranged at the center of the floor of the building 10 where the building 10 is installed (the second floor).

  As shown in FIG. 2, the radiation shielding structure 30 constitutes a linac chamber in which linacs (radiotherapy apparatuses) are arranged. The radiation shielding structure 30 has a shielding floor, a shielding ceiling, and a shielding wall. The shielding floor, shielding ceiling, and shielding wall have a thickness of about 1 m to about 3 m, and are constituted by concrete 31 in which reinforcing bars are embedded. The concrete 31 is fixed to the plurality of columns 21. As a result, the radiation shielding structure 30 is constituted by a steel concrete structure integrally fixed to the plurality of columns 21. Furthermore, a radiation shielding member 35 made of an iron plate or the like is embedded in all of the shielding floor, shielding ceiling, and shielding wall.

  Further, concrete 25 in which reinforcing bars are embedded is placed on the outer peripheral portion of the column 21 to which the concrete 31 of the radiation shielding structure 30 is attached at a lower floor than the radiation shielding structure 30. Therefore, the column 21 constituting the lower floor immediately below the radiation shielding structure 30 is configured with a steel reinforced concrete structure.

The structure of the building 10 described above is based on the following concept.
In the case of a seismic isolation structure, most of the seismic energy is consumed in the seismic isolation layer. For this reason, the frame in the upper part of the seismic isolation layer is designed to be elastic against the seismic energy generated by extremely rare earthquakes, and even if an unexpected large earthquake occurs, the frame's plastic deformation capacity will be reduced. Can afford to not collapse.
In addition, since the seismic isolation structure has a long natural period of the building (building), the response characteristics are different from those of the earthquake-resistant structure, and resonance with earthquake motion does not occur.

  For this reason, even when a heavy, high-rigidity frame is installed on a higher floor than the upper floor of the seismic isolation layer, the effect of sudden changes in rigidity can be reduced and the rigidity Relaxation of shear force concentration can be expected on high walls.

Hereinafter, the conditions and results of the simulation performed to verify the above-described idea will be described.
FIG. 3A shows the mass point system model of each floor of the building 10, the weight of each floor, the accumulated weight up to that floor, and the relative ratio of the weight to the comparison target. FIG. 3B shows the mass system model of each floor, the weight of each floor, and the total weight up to that floor when the radiation shielding structure 30 is directly above the seismic isolation layer (here, the first floor). . In the building 10 of the present embodiment, the accumulated mass for the third floor is increased by 17.5%, and the accumulated mass for the second floor is increased by 15% compared to the building to be compared.

  FIG. 4 shows a simulation result in the building 10 of this embodiment and the building to be compared. In addition, the building 10 of this embodiment is a structure which installed the radiation shielding structure 30 in the 2nd floor (the upper floor of the 2nd hierarchy from a seismic isolation layer) as shown to Fig.3 (a), and is a comparison object As shown in FIG. 3 (b), the building has a structure in which a radiation shielding structure 30 is installed on the first floor (the floor directly above the seismic isolation layer).

FIG. 4A shows the maximum response absolute acceleration at each floor, and FIG. 4B shows the maximum layer shear force between the layers.
As shown to Fig.4 (a), although the maximum response absolute acceleration (response acceleration) in the building 10 of this embodiment has increased on the 4th floor and the 3rd floor, it has decreased as the whole building. In particular, the response acceleration above the fifth floor is reduced, and the response acceleration of the floor surface on which the radiation shielding structure 30 is installed is reduced by 10%.

  As shown in FIG. 4 (b), the maximum layer shear force (layer shear force) in the building 10 of this embodiment increases between the first floor and the seismic isolation layer, between the second floor and the first floor. ing. However, although the weight of the second floor or more of the building 10 has increased by 15% or more, the layer shear force of the building 10 has increased only by about 4%. In addition, the layer shear force of the upper floor is lower by about 10% than the third floor.

According to this embodiment, the following effects can be obtained.
(1) In this embodiment, the building 10 includes the seismic isolation layer 11 and the radiation shielding structure 30, and the radiation shielding structure 30 is located on the second upper floor (second floor) with respect to the seismic isolation layer 11. Arranged. As a result, it is possible to secure a one-level layout freedom and to reduce the maximum response absolute acceleration due to an earthquake on the installation floor (second floor) of the radiation shielding structure 30. Furthermore, the maximum response absolute acceleration of the entire building 10 can also be reduced.

  (2) In this embodiment, the radiation shielding structure 30 of the building 10 is disposed at the center of the installation floor. Thereby, since the distance from the heavy radiation shielding structure 30 to each pillar 21 becomes short, the shear force which concentrates the radiation shielding structure 30 from each pillar 21 can be made small.

  (3) In the present embodiment, the outer peripheral portion of the column 21 to which the concrete 31 of the radiation shielding structure 30 is attached on the lower floor than the radiation shielding structure 30 is composed of concrete 25 in which reinforcing bars are embedded. Thereby, the support performance by the bearing pressure of the concrete 25 can be expected, and the fixing degree of the column 21 directly below the radiation shielding structure 30 can be improved. Therefore, the heavy radiation shielding structure 30 can be supported more firmly against axial force, shearing and bending.

Moreover, you may change the said embodiment as follows.
In the above embodiment, the building 10 has the radiation shielding structure 30 installed on the upper floor of the second layer of the seismic isolation layer 11. What is necessary is just to arrange | position a radiation shielding structure to an upper floor rather than the directly upper floor of a seismic isolation layer. For example, as shown in FIG. 5, it is good also as the building 50 which has arrange | positioned the radiation shielding structure 30 in the upper floor of the 3rd hierarchy of the seismic isolation layer 11. As shown in FIG. In this building 50, the columns 51 and the beams 52 are made of steel frames. Furthermore, concrete 55 in which reinforcing bars are embedded is placed on the outer periphery of the column 51 to which the concrete 31 of the radiation shielding structure 30 is attached at a lower floor than the radiation shielding structure 30 of the building 50. . Further, a vibration damper 57 such as an oil damper is disposed on a lower floor than the radiation shielding structure 30 of the building 50. Thereby, the whole building 10 can be controlled with respect to vibrations, such as an earthquake.
Furthermore, even when the radiation shielding structure 30 is installed on the upper floor of the second layer of the seismic isolation layer 11 as in the above embodiment, a damping damper is installed on the lower floor than the radiation shielding structure 30. May be.

  -In the said embodiment, the radiation shielding structure 30 was arrange | positioned in the center of the installation floor of the buildings 10 and 50. FIG. The installation position of the radiation shielding structure 30 is not limited to the center of the installation floor. For example, it is not necessary to be exactly the center position of the installation floor, and a position close to the center such as an area including the center is preferable.

  -In the said embodiment, the building 10 assumed the building of 8 stories. A building having a radiation shielding structure is not limited to an eight-story building as long as it has a layer other than the floor directly above the seismic isolation layer. For example, the present invention can be applied to a high-rise building having 9 floors or more and a low-rise building having 2 floors or 3 floors.

  DESCRIPTION OF SYMBOLS 10,50 ... Building, 11 ... Seismic isolation layer, 11a ... Seismic isolation device, 21,51 ... Column, 22,52 ... Beam, 25,31,55 ... Concrete, 30 ... Radiation shielding structure, 35 ... Radiation shielding Member, 57 ... damping damper.

Claims (4)

In buildings with seismic isolation layers and radiation shielding structures,
A building characterized in that a radiation shielding structure is arranged on an installation floor above a floor directly above the seismic isolation layer.   The building according to claim 1, wherein the radiation shielding structure is arranged on an upper floor of a second hierarchy with respect to the seismic isolation layer.   The building according to claim 1 or 2, wherein a vibration damper is provided in a layer between the layer in which the radiation shielding structure is provided and the seismic isolation layer.   The steel layer-reinforced concrete structure column is provided in a layer between the layer in which the radiation shielding structure is provided and the seismic isolation layer. Building.