JPH11172760A - Base-isolating footing structure of building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To base-isolate low-rise buildings of about one to three stories, mainly dwelling houses, and to rationalize a footing structure. SOLUTION: The surface 1 of the ground is rolled, footing parts 2 made of PC boards or the like are installed, and base isolators 3 are placed on the footing parts 2. A space truss 4 such that the number of lower chords 4a is 1 grid smaller than the number of upper chords 4b is mounted on the base isolators 3, with the apexes 4d of the space truss 4 installed on the base isolators 3. The corners of a building are installed on the space truss 4, and columns 5 and floor slabs 6 are placed. The space truss 4 used may have a spread in the form of a plane or may be made in a straight line or may be dotted. Floor slabs may be placed in place of the upper chords 4b of the space truss 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base-isolation basic structure of a building which is advantageously applied to a low-rise, one-story, three-story, low-rise building mainly intended for a house.

[0002]

2. Description of the Related Art In recent years, seismic isolation foundation structures are often used even in buildings that are low-rise and lightweight compared to high-rise buildings such as houses. An example of a base isolation structure used in such a low-rise building will be described with reference to the drawings.

A base isolation structure shown in FIG. 7 (first known example)
Crosses the foundation beam 52 over the adjacent seismic isolation device 51,
On the foundation beam 52, a wall or a pillar 53 as an upper structure is installed so that the axis 51a of the seismic isolation device 51 and the axis 53a coincide with each other. In this seismic isolation base structure, the load of the upper structure is transmitted to and supported by the seismic isolation device 51 via the wall or the column 53.

As described above, since the axis 53a of the wall or column 53 and the axis 51a of the seismic isolation device 51 coincide with each other, no bending moment or shearing force acts on the foundation beam 52. Therefore, the foundation beam 52 is made of a lightweight and simple shape.

[0005] Seismic isolation foundation structure shown in FIG. 8 (second known example)
Crosses the foundation beam 54 above the adjacent seismic isolation device 51,
A wall or a pillar 53 is installed on the foundation beam 54 at a position substantially coincident with the outer peripheral portion of the seismic isolation device 51. In this seismic isolation base structure, the axis 51a of the seismic isolation device 51 and the axis
53a does not match. For this reason, the load of the upper structure is transmitted from the wall or column 53 to the seismic isolation device 51 via the foundation beam 54.

Accordingly, the foundation beam 54 is provided with the load of the upper structure acting on the wall or the column 53 and the distance between the wall and the column 53 and the center of the seismic isolation device 51 corresponding to the load (FIG. The bending moment shown in (b) and the shearing force shown in FIG. (c) act on the foundation beam 54, and both the bending strength and the bending rigidity are set large.

[0007]

In the first known example,
Since the axis of the wall or the column is aligned with the axis of the seismic isolation device, no bending moment acts on the foundation beam, which is mechanically advantageous. However, there is a problem that the seismic isolation device protrudes from the outer periphery of the building, and particularly when the site is narrow, it becomes a hindrance when a person passes.

In the second known example, since the axis of the wall or the column does not coincide with the axis of the seismic isolation device, the bending moment or the shear corresponding to the load of the upper structure and the separation distance between the two axes are added to the foundation beam. The force is applied and the foundation beam or floor is
It is necessary to make it robust by construction. For this reason, there is a problem that the labor and cost required for manufacturing the foundation beam or the floor increase.

[0009] It is an object of the present invention to prevent the seismic isolation device from protruding from the outer periphery of the building, allow the axis of the seismic isolation device to be displaced from the axis of the wall or column, and furthermore, to prevent the piping and wiring under the floor from being disturbed. An object of the present invention is to provide a base-isolated foundation structure of a building that can facilitate construction.

[0010]

According to the present invention, there is provided a seismic isolation base structure for a building according to the present invention, in which a space truss is disposed on a base portion via a seismic isolation device. A seismic isolation base structure of a building in which a building is installed, wherein the space truss is arranged on a seismic isolation device at a lower chord material side that is one grid less than an upper chord material, and at least a corner of the building is installed on the space truss. It is composed of

In the above seismic isolation base structure of a building, a space truss arranged on a seismic isolation device installed on the foundation part is
Since the lower chord material is one grid smaller than the upper chord material and the corner of the building is installed on the space truss, the seismic isolation device can be installed so as not to protrude from the outer periphery of the building. That is, by setting the plane dimensions of the seismic isolation device to be equal to or smaller than one grid of the space truss,
The seismic isolation device does not protrude from the periphery of the building.

[0012] Further, despite the fact that the axis of the wall or column constituting the upper structure does not coincide with the axis of the seismic isolation device, the load of the upper structure is applied to the shaft of the seismic isolation device via the diagonal members of the space truss. Can act on the wick. Therefore, the load can be rationally supported.

In the above seismic isolation base structure for a building, it is preferable that the upper chord of the space truss also serves as the floor material of the building. By configuring the base isolation structure as described above, it is possible to reduce the number of constituent members of the entire building and reduce the weight of the building.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the base isolation structure of a building will be described below with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a base isolation structure according to a first embodiment, FIG. 2 is a diagram illustrating a configuration example of a space truss, and FIG. 3 is a diagram illustrating another configuration example of a space truss. 4 is a diagram illustrating a base isolation structure according to the second embodiment, FIG. 5 is a diagram illustrating the configuration of a space truss used in the second embodiment, and FIG. 6 is a diagram illustrating a base isolation structure according to the third embodiment. FIG.

The seismic isolation base structure according to each of the following embodiments can use a space truss to realize seismic isolation of low-rise buildings of one to three levels mainly for houses and simplification of construction. It is configured as follows.

The seismic isolation base structure according to the first embodiment will be described with reference to FIG. In the figure, a foundation 2 is constructed on the ground 1 in accordance with the foundation drawing of the target building,
Seismic isolation devices 3 are arranged on the base portions 2 respectively. In the seismic isolation device 3, a space truss 4 configured as shown in FIG. 2 is arranged by directly placing the lower chord material 4 a on the seismic isolation device 4. At least the corners of the building are installed on the space truss 4, and columns or walls (hereinafter, referred to as “walls”) 5 and floor boards 6 of the building are placed thereon.

The configuration of the base 2 is not limited.
That is, the foundation 2 is appropriately selected and employed, for example, a continuous foundation, an independent foundation, a solid foundation, or a pile foundation or ground improvement, which is optimal in accordance with the weight of the upper structure and the state of the ground 1. Is possible. In the present embodiment, after the ground 1 is compacted, the base plate 2 is constructed by installing a PC board on the compacted portion.

Therefore, when constructing the foundation 2, it is possible to simplify earthwork such as excavation of the ground 1, and it is possible to reduce the labor and cost of the residual soil treatment.

The seismic isolation device 3 only has to have a so-called seismic isolation function, and the structure is not limited. That is, it is possible to selectively use a laminated rubber type, a sliding bearing type, an FPS type, a bearing supporting type, etc., which are currently provided as seismic isolation devices.

The seismic isolation device 3 is arranged on the base 2 at a plurality of positions set in advance in the design stage, and is fixed to the base 2 in a method set in advance according to the selected seismic isolation device 3. Have been. At this time, the seismic isolation device 3 is arranged such that the position of the shaft core 3a can coincide with the end (apex 4d) of the lower chord member 4a of the space truss 4.

As shown in FIG. 2, the space truss 4 comprises a lower chord member 4a, an upper chord member 4b, and a diagonal member 4c. These members 4a to 4c constitute a quadrangular pyramid-shaped structural unit. The truss is configured as a truss having a planar spread in which the constituent units are connected.

The dimensions (lengths of the lower chord 4a and the upper chord 4b) of one grid constituting the space truss 4 are equal to or substantially equal to the plane dimensions of the seismic isolation device 3, and the lower chord 4a is formed. The side is arranged one grid less than the upper chord material 4b side, and is configured such that the upper base of the isosceles trapezoid is arranged on the lower side in side view. The relationship between the dimensions of one grid constituting the space truss 4 and the plane dimensions of the seismic isolation device 3 is not particularly limited, and the plane dimensions of the seismic isolation device 3 may be smaller than the dimensions of one grid. possible.

Therefore, when the space truss 4 is placed with the apex 4d formed at the end of the lower chord material 4a coincident with the axis 3a of the seismic isolation device 3, the end of the upper chord material 4b of the space truss 4 is placed. Position coincides with or is outside the surface of the outer part of the seismic isolation device 3. Further, the area surrounded by the members 4a to 4c becomes a continuous window shape, and the equipment pipes and the like installed under the floor are drawn in using the areas, or the worker is required to perform maintenance when the pipes and the like or the seismic isolation device 3 are maintained. It is possible to break in.

The wall 5 constitutes a building installed on the upper part of the space truss 4 and is arranged on the outer periphery of the building and on the outer periphery of the space truss 4. This wall 5
A part of the weight of the building acts as a vertical load on the (or column), and the load is transmitted to the space truss 4 directly or to the space truss 4 via the floor plate 6.

As described above, since the wall 5 is disposed at the end of the upper chord member 4b of the space truss 4, the axis 5a of the wall 5 has a predetermined dimension with respect to the axis 3a of the seismic isolation device 3. Only eccentricity.

The floor plate 6 is made of a plate material selected from plywood, a PC plate, an ALC plate, or a sandwich panel having a metal plate on both sides of a core material and having strength. It is installed with the upper part laid all over.

In the seismic isolation base structure of the first embodiment configured as described above, the space truss 4 is arranged above the seismic isolation device 3 with the lower chord 4a facing down. Is attached, the end side of the upper chord material 4b of the space truss 4 is shifted from the shaft center 3a of the seismic isolation device 3 by one.
/ 2 grids.

Therefore, the plane dimensions of the seismic isolation device 3 and the upper chord material 4
By setting the relationship with the dimension b in advance, it becomes possible to install the seismic isolation device 3 without protruding from the outer periphery of the building. Further, for example, even when the dimension of one grid of the space truss 4 is substantially equal to the plane dimension of the seismic isolation device 3 (the plane dimension of the seismic isolation device 3 is slightly larger than the dimension of one grid), The thickness dimension can be taken into account, so that if the dimensional difference is smaller than the thickness of the wall 5, the seismic isolation device 3 will not protrude from the outer periphery of the building.

The load transmitted to the upper chord member 4b located on the outer peripheral portion of the space truss 4 via the wall 5 applies a compressive force to the diagonal member 4c constituting the space truss 4 to apply the load to the seismic isolation device 3. Transmitted to the ground 1 via the seismic isolation device 3 and the base 2
The shaft 5a of the wall 5 and the shaft 3a of the seismic isolation device 3 do not coincide with each other, but no bending moment is applied to the space truss 4.

In this embodiment, a space truss 4 having a planar spread as shown in FIG. 2 was used. However, the space truss 4 does not necessarily need to be configured to have a planar spread, and may be, for example, a linear space truss 4 as shown in FIG. In this case, the space truss 4 is installed over the adjacent seismic isolation device 3 and the vertex 4 d of the end is set to coincide with the axis 3 a of the seismic isolation device 3.

FIG. 4 is a view for explaining a base isolation structure according to the second embodiment. In this embodiment, as shown in FIG.
A three-dimensional truss 4 is used which is formed in an inverted quadrangular pyramid shape by the upper chord member 4b and the diagonal member 4c.

The space truss 4 is arranged for each seismic isolation device 3 installed on the base part 2, the vertex 4 d is made to coincide with the axis 3 a of the seismic isolation device 3, and further, the upper chord 4 b of the space truss 4
The seismic isolation base is formed by hanging the floor beam 8 on the top and fixing the floor beam 8 and the space truss 4 to each other.

That is, in this embodiment, the space truss 4 is formed in a point shape corresponding to the seismic isolation device 3. Even in this case, by aligning the axis 5a of the wall 5 with the upper part of the upper chord member 4b arranged on the outer peripheral portion of the space truss 4, the wall 5
Is transmitted to the space truss 4 via the floor beam 8, and a compressive force is applied to the diagonal member 4c to be transmitted from the seismic isolation device 3 and the foundation 2 to the ground 1 to be supported.

FIG. 6 is a view for explaining the configuration of the base isolation structure according to the third embodiment. In this embodiment, the space truss 4 is configured by using a floor slab 9 instead of the upper chord material 4b. The space truss 4 of the present embodiment may be configured in a plane as shown in FIG. 2 or may be configured in a straight line as shown in FIG.

The structure of the floor slab 9 is not particularly limited. Like the floor plate 6 in the first embodiment, a plywood, a PC board,
It can be selectively used from an ALC plate or a sandwich panel having a proof stress.

The floor plate 6 of the first embodiment may be simply placed on the space truss 4. However, the floor slab 9 of this embodiment has a function as a member constituting the space truss 4, and one end of the diagonal member 4 c constituting the space truss 4 is provided on the lower chord material 4 a and the other end is provided on the floor slab 9. Attached to.

Even in the base isolation structure constructed as described above, the seismic isolation device 3 does not protrude from the outer peripheral portion of the building as in the first embodiment, and the space truss 4 and the floor slab 9
The load acting on the wall 5 can be transmitted from the base isolation device 3 and the foundation 2 to the ground 1 without applying a bending moment to the ground 1.

[0038]

As described above in detail, in the base isolation structure for a building according to the present invention, the base isolation device does not protrude from the outer periphery of the building. For this reason, when building a building with seismic isolation when the site is narrow and the distance between the building and the adjacent land boundary is small, even if people pass through the boundary part, the seismic isolation device may be a hindrance. There is no such thing. Also, in the case of performing plumbing work or the like between the building and the adjacent land boundary, the seismic isolation device does not hinder.

Since at least the corners of the building are installed on the space truss, the load acting on the columns or walls installed on the space truss is transmitted to the seismic isolation device via the diagonal members. Therefore, even when the axis of the pillar does not match the axis of the seismic isolation device, no bending moment or shearing force acts on the space truss, and the space truss that serves as the structure directly above the seismic isolation device is used. There is no need to make it particularly robust, and labor and cost can be reduced.

In a building having a seismic isolation structure, when equipment piping is installed under the floor, a flexible portion is configured to absorb vibration or expansion and contraction generated in the piping. Even in such a case, since the equipment piping under the floor can be installed through a portion surrounded by the members constituting the space truss, it is easy to install a flexible portion outside the building, The maintainability of the flexible portion can be improved.

When constructing a space truss, the dimensions of the upper chord, lower chord and diagonal can be set as appropriate. For this reason, maintenance and replacement work of the seismic isolation device can be easily performed by setting a size that allows a person to pass through a region surrounded by the members.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a base isolation base structure according to a first embodiment.

FIG. 2 is a diagram illustrating a configuration example of a space truss.

FIG. 3 is a diagram illustrating another configuration example of the space truss.

FIG. 4 is a diagram illustrating a base isolation base structure according to a second embodiment.

FIG. 5 is a diagram illustrating a configuration of a space truss used in a second embodiment.

FIG. 6 is a diagram illustrating a base isolation base structure according to a third embodiment.

FIG. 7 is a diagram illustrating a seismic isolation base structure of a first known example.

FIG. 8 is a diagram illustrating a seismic isolation base structure of a second known example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ground 2 Base part 3 Seismic isolation device 3a Shaft core 4 Space truss 4a Lower chord material 4b Upper chord material 4c Diagonal material 4d Apex 5 Wall (or pillar) 6 Floor plate 8 Floor beam 9 Floor slab

Claims (2)

[Claims] 1. A seismic isolation base structure of a building in which a space truss is arranged on a foundation portion via a seismic isolation device, and a building is installed on the space truss, wherein the space truss is higher than the upper chord material. The lower chord material side one grid less is placed on the seismic isolation device,
A base isolation structure for a building, wherein at least a corner of the building is installed on the space truss. 2. The base isolation structure of a building according to claim 1, wherein the upper chord of the space truss also serves as a floor material of the building.