JP2021031930A - Method for designing foundation structure of detached building - Google Patents

Abstract

To provide a method for designing the foundation structure of a detached building, which enables the design of the foundation structure of a detached building having a column foundation at low cost and in a short time.SOLUTION: A outer peripheral underground beam 30A is provided at a bottom of an outer wall of a detached building. Inside the outer peripheral underground beam 30A, a solid foundation portion 20 having a slab foundation main reinforcement structural portion having a plurality of main reinforcements intersecting each other in the horizontal direction is formed. Along the lower part of the internal bearing wall of a detached building and the part between the slab foundation main bar structures adjacent to each other, an internal underground beam 30B that forms the slab foundation portion 20 in a plurality of sections is formed endlessly. The slab foundation portion 20 has a maximum size of one section of 4550 mm or less in each of the vertical and horizontal directions. A columnar foundation structure 40 is formed at least at the lower part of the column of the detached building and along the internal underground beam 30 at an interval of 1820 mm or less. When the distance between the columnar foundation structures 40 adjacent to each other is 910 mm or more, a floor bundle is formed in an intermediate portion.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for designing a foundation structure of a detached building having a columnar foundation structure.

Conventionally, as a building foundation that supports the foundation of a detached building such as a wooden structure, for example, a building foundation having a rising wall portion and a cloth foundation and a solid foundation forming between the rising wall portion and the cloth foundation has been used. Widely used.
In such a detached building, moisture tends to stay under the floor, so there is a great demand for a technology for improving the air cycle efficiency under the floor.
On the other hand, various techniques are disclosed as techniques for improving the air cycle efficiency of a detached building (see, for example, Patent Document 1).

However, even if the technique described in Patent Document 1 improves the air cycle between the underfloor and the attic in a detached building, an opening is formed in the cloth foundation under the floor where moisture or the like tends to stay. It is difficult to greatly improve the air cycle efficiency under the floor because the improvement of the air cycle efficiency is limited.

Therefore, for example, a column foundation (columnar foundation structure), which is a cylindrical independent foundation, is disclosed as a technology applicable to improving air cycle efficiency by reducing the wall portion of a cloth foundation or the like erected under the floor. (See, for example, Patent Document 2). The column foundation is arranged so as to be superposed on a linearly extending underground beam, and includes, for example, a column main bar that rises vertically and a cylindrical concrete portion that covers the main bar.

Conventionally, when designing a foundation structure including a column foundation for a detached building, the foundation structure is individually designed according to the ground bearing capacity, the weight of the building, the floor plan in the building, etc. for each detached building to be built. There is.

Jikken Sho 63-040570 Gazette Japanese Unexamined Patent Publication No. 11-043951

However, in the conventional foundation structure design method in which the arrangement position of the column foundation is individually designed for each detached building to be built, it takes time and cost to design the foundation structure, which causes an increase in construction cost. It was.

The present invention has been made in consideration of such circumstances, and is capable of designing a foundation structure of a detached building having a column foundation at low cost in a short time. The purpose is to provide a method.

In order to solve the above problems, the present invention proposes the following means.
That is, the method for designing the foundation structure of a detached building of the present invention is applied to a detached building having two or less floors of wood, and is a detached building using a columnar foundation structure erected on a solid foundation. This is a method of designing the basic structure of the above, in which an outer peripheral underground beam is provided in the lower part of the outer wall of the detached building, and a slab having a plurality of main bars intersecting each other in the horizontal direction inside the outer peripheral underground beam. A solid foundation part having a foundation main bar structure is formed, and the solid foundation part is divided into a plurality of sections along the lower part of the internal bearing wall of the detached building and between the adjacent slab foundation main bar structures. The internal underground beams to be formed are formed in an endless shape so that the maximum size of the one section is 4550 mm or less in each of the vertical and horizontal directions, and the columnar foundation structure is at least the detached building. When the distance between the lower part of the pillar and the inner underground beam is 1820 mm or less and the distance between the columnar foundation structures adjacent to each other is 910 mm or less, a floor bundle is formed in the intermediate part. It is a feature.

Further, in the present invention, the columnar foundation structure further formed on the solid foundation portion bears a floor load of 16.0 m ² or less of the floor area of the first floor portion of the detached building. It may be arranged as follows.

Further, in the present invention, the columnar foundation structure may have a rising height from the solid foundation of 425 mm or less and a diameter of 350 mm or more.

According to the present invention, it is possible to provide a method for designing a foundation structure of a detached building, which enables designing a foundation structure of a detached building having a column foundation at low cost and in a short time.

It is a perspective view explaining the state which installed the foundation on the building foundation. It is a perspective view explaining the schematic structure of installing a foundation on a building foundation. It is a top view for demonstrating the outline of a building foundation. It is a figure explaining the schematic structure of the building foundation, and is the cross-sectional view shown by the arrow view IV-IV in FIG. It is a schematic plan view which shows the arrangement of each part based on the design method of the foundation structure of the detached building of this invention. It is explanatory drawing which shows the example of division by the internal underground beam of a solid foundation part (slab floor). It is explanatory drawing which shows the Example of this invention.

Hereinafter, a method of designing a basic structure of a detached building according to an embodiment of the present invention will be described with reference to the drawings. It should be noted that each of the embodiments shown below is specifically described in order to better understand the gist of the invention, and is not limited to the present invention unless otherwise specified. In addition, the drawings used in the following description may be shown by enlarging the main parts for convenience in order to make the features of the present invention easy to understand, and the dimensional ratios of the respective components are the same as the actual ones. Is not always the case.

First, a schematic configuration of a building foundation including a columnar foundation structure formed by the columnar foundation structure molding member of the present invention will be described.
FIG. 1 is a perspective view for explaining a state in which a foundation is installed on a building foundation, and FIG. 2 is a perspective view for explaining a schematic configuration of the building foundation.
The building foundation 1 includes a rising wall portion 10 erected around a detached building (not shown) such as a two-story house, a solid foundation portion 20, an underground beam 30, and a column base (columnar column). It includes a foundation structure) 40 and a floor bundle 60.
Further, the concrete portions constituting the rising wall portion 10, the solid foundation portion 20, the underground beam 30, and the column base 40 are integrally formed.

Then, the base 2 of the detached building (not shown) is arranged on the rising wall portion 10, and the pillars (not shown) of the detached building are erected. Further, a base 2 and a pillar (not shown) are appropriately erected between the column bases 40 formed on the underground beam 30.
A floor bundle 60 is provided below the base 2 and below the large pull 6 as needed.

FIG. 3 is a plan view showing a schematic configuration of a building foundation, and FIG. 4 is a cross-sectional view illustrating the schematic configuration shown by arrow IV-IV in FIG. It should be noted that FIGS. 3 and 4 are shown by simplifying a part of FIGS. 1 and 2 for convenience.

The rising wall portion 10 is erected, for example, so as to correspond to the outer wall circumference (outer circumference) of the detached building, and is formed around the solid foundation portion 20. The rising wall portion 10 includes a rising wall portion main bar 11 and a rising wall portion concrete portion 15.

The rising wall portion main bar 11 includes a rising portion 11A and a fixing portion 11B, and the fixing portion 11B is embedded in the solid foundation portion 20.
The rising wall concrete portion 15 is formed so as to cover the rising wall 11A.

The solid foundation portion (slab floor) 20 is formed in, for example, an inner area surrounded by the rising wall portion 10, and includes a slab foundation main bar structure portion 22 and a solid foundation concrete portion 25.

The slab foundation main bar structure portion 22 has a plurality of main bars 22X horizontally arranged along the long side (first direction: X direction) of the rising wall portion 10 and a short side orthogonal to the direction in which the main bars 22X are arranged. It includes a plurality of main bars 22Y formed along (second direction: Y direction).
The solid foundation concrete portion 25 has a thickness of, for example, about 200 mm, and is formed so as to cover the slab foundation main bar structure portion 22.

The underground beam 30 is formed by overlapping the outer peripheral underground beam 30A arranged at the lower part of the rising wall portion 10 and the solid foundation portion 20 in the inner area surrounded by the outer peripheral underground beam 30A. It consists of a beam 30B. Such an underground beam 30 has a greater rigidity than the solid foundation portion 20.
Further, the internal underground beam 30B is formed along the long side (first direction: X direction) or the short side (second direction: Y direction) of the rising wall portion 10.

In this embodiment, the internal underground beam 30B includes an underground beam main reinforcement structure portion 31, a diamond reinforcement reinforcement portion (reinforcing reinforcement structure portion) 34, and an underground beam concrete portion 35.
The underground beam main bar structure portion 31 includes, for example, a plurality of underground beam main bars 32 and a plurality of stirrups (band bars) 33.

The plurality of underground beam main bars 32 are formed, for example, along the long side or the short side of the rising wall portion 10, and two (plural) underground beam main bars 32 extending in parallel and arranged horizontally are formed. It is configured so that two sets (plurality) are arranged in the vertical direction.

Further, the underground beam main bars 32 arranged vertically are configured to connect the underground beam main bars 32 in the vertical direction by, for example, surrounding them with a stirrup (band bar) 33.
The underground beam main bars 32 arranged vertically may be connected on the left, right, and lower sides to connect the underground beam main bars 32 in the vertical direction.

Further, in this embodiment, the diamond reinforcement portion 34 is formed below the position where the column base 40 is installed in the underground beam 30.
The diamond reinforcement portion 34 includes, for example, two (plurality) first reinforcements 34A extending in parallel with the underground beam main reinforcement 32 at an intersection angle of 45 ° with the underground beam main reinforcement structure portion 31 interposed therebetween. Two (s) extending in a direction symmetric with respect to the first reinforcing bar 34A and the underground beam main bar structure 31 with the underground beam main bar structure 31 in between, that is, in a direction orthogonal to the first reinforcing bar 34A. It is provided with a second reinforcing bar 34B.

The underground beam concrete portion 35 is formed so as to cover the underground beam main bar structure portion 31, and for example, the thickness in the vertical direction is about 300 mm, which is thicker in the vertical direction than the solid foundation concrete portion 25. It is formed.

(Columnar foundation structure molding member)
Next, the arrangement design of the column base (columnar foundation structure) based on the design method of the foundation structure of the detached building of the present invention will be described.
The detached building applicable to the method for designing the basic structure of the detached building of the present invention is as follows.
(1) Structure: Wooden (conventional frame construction method)
(2) Building use: Detached house (3) Number of floors: 2 stories (4) Maximum height: 13 m or less (5) Maximum eaves height: 9 m or less (6) Floor height: 2.4 m to 3.0 m
(7) Ground bearing capacity: 20 kN / m ² or more

First, in designing, the bearing capacity of the land on which the wooden two-story detached building will be built is confirmed. ^{This requires that the bearing capacity be 20 kN / m 2} or more, for example, by a ground survey, for example, a Swedish sounding test. If the bearing capacity is ^{less than 20 kN / m 2,} it is necessary to additionally carry out ground improvement and reinforcement work.

Next, the positions of the columns and bearing walls of the detached building to be built are confirmed from the design drawings. For bearing walls, wall amount calculation and balance check shall be performed based on Article 46 of the Building Standards Act Enforcement Ordinance. The positions of the columns and bearing walls confirmed here will be referred to when designing the arrangement of the column base (columnar foundation structure), which will be described later.

FIG. 5 is a schematic plan view showing the arrangement of each part based on the design method of the basic structure of the detached building of the present invention.
[Arrangement of outer peripheral foundation / inner underground beam and slab]
(1) The outer peripheral underground beam 30A is arranged on the outer periphery of the building.
(2-1) The internal underground beam 30B is always arranged under the internal bearing wall W1.
(2-2) The internal underground beam 30B is arranged on the line that partitions the solid foundation portion (slab floor) 20.
(2-3) Both ends of the inner underground beam 30B are arranged so as to be in contact with the outer peripheral underground beam 30A or another inner underground beam 30B, and the inner underground beam 30B is made endless.
(3) The maximum size of the solid foundation portion (slab floor) 20 of one section surrounded by the outer underground beam 30A and the inner underground beam 30B shall be 4550 mm or less in each of the vertical and horizontal directions.
If the size of the solid foundation (slab floor) 20 in one section exceeds 4550 mm in each of the vertical and horizontal directions, an internal underground beam 30B is provided to divide the solid foundation (slab floor) 20 into two or more. To do.
FIG. 6 shows an example of division of the solid foundation portion (slab floor) 20 by the internal underground beam 30B.

[Column-based layout]
(1) A column base (columnar foundation structure) 40 is arranged directly below the column P1.
(2) The column base 40 is basically arranged on the internal underground beam 30B. However, the column base 40 satisfying the following conditions (2-1) and (2-2) may be arranged on the solid foundation portion (slab floor) 20.
(2-1) Column base 40 located off the line of the internal underground beam 30B.
(2-2) Directly under the case where there is a pillar only on the 1st floor, or directly under the case where there is no pillar and only the floor load on the 1st floor is borne (base / large pull). In this case, the floor area of the first floor borne by the column base 40 shall be within ^{16.0 m 2.} As an example, when the floor size of the location is 3.64 m × 3.185 m in length and width, the floor area is 11.6 m ² =, which ^{fits within 16.0 m 2} , so that the column base 40 can be installed.
(3) The column base 40 is formed at least at an interval of 1820 mm or less along the lower part of the pillar P1 of the detached building and the internal underground beam 30B. Then, when the distance between the adjacent column bases 40 is 910 mm or more, a floor bundle 60 (see FIG. 1) is formed in the intermediate portion.

Based on the method of designing the foundation structure of the detached building of the present invention as described above, if the outer peripheral foundation, the internal underground beam, and the slab floor are arranged, and further the column base is arranged, individual doors can be arranged as in the conventional case. It is not necessary to design the column-based layout each time according to the structure of the building.
Therefore, it is possible to provide a method for designing the foundation structure of a detached building, which enables the design of the foundation structure of a detached building having a column foundation at low cost and in a short time.

FIG. 7 shows an example in which the arrangement of the column base is designed based on the design method of the foundation structure of the detached building of the present invention.
According to such an embodiment, only by specifying the outer underground beam 30A, the inner underground beam 30B, the solid foundation (slab floor) 20, etc. based on the plan view of the detached building, the column follows the above-mentioned design rule. The placement position of the base can be easily set.

Although some embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, as well as in the scope of the invention described in the claims and the equivalent scope thereof.

1 Building foundation 2 Foundation 3 Pillar 6 Large pull 7 Joist 10 Rising wall part 11 Rising wall part Main bar 11A Rising part 11B Fixing part 15 Rising wall part Concrete part 20 Solid foundation part (slab floor)
22 Slab foundation main reinforcement structure 25 Solid foundation concrete part 30 Underground beam 30A Outer ground beam 30B Inner underground beam 31 Underground beam main reinforcement structure 32 Underground beam main reinforcement 33 Stirrup (belt)
34 Diamond reinforcement reinforcement part (reinforcement reinforcement structure part)
35 Underground beam concrete part 40 Column base (columnar foundation structure)

Claims (3)

It is a method of designing the foundation structure of a detached building using a columnar foundation structure erected on a solid foundation, which is applied to a detached building of two stories or less.
An outer underground beam is provided at the bottom of the outer wall of the detached building.
Inside the outer peripheral underground beam, a solid foundation portion having a slab foundation main reinforcement structural portion having a plurality of main reinforcements intersecting each other in the horizontal direction is formed.
An endless internal underground beam is formed along the lower part of the internal bearing wall of the detached building and between the slab foundation main bar structural portions adjacent to each other to form the solid foundation portion in a plurality of sections.
For the solid foundation, the maximum size of one section should be 4550 mm or less in each of the vertical and horizontal directions.
The columnar foundation structure is formed at least at the lower part of the pillar of the detached building and along the internal underground beam at an interval of 1820 mm or less.
A method for designing a foundation structure of a detached building, which comprises forming a floor bundle in an intermediate portion when the distance between the columnar foundation structures adjacent to each other is 910 mm or more. The columnar foundation structure further formed on the solid foundation portion shall be arranged so that the floor load to be borne is 16.0 m ² or less of the floor area of the first floor portion of the detached building. The method for designing a foundation structure of a detached building according to claim 1, which is a feature. The method for designing a foundation structure of a detached building according to claim 1 or 2, wherein the columnar foundation structure has a rising height from the solid foundation of 425 mm or less and a diameter of 350 mm or more.

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