JP6529009B2 - Construction method of foundation for building - Google Patents

Description

  The present invention relates to a foundation structure for a building, a construction method of a foundation for a building, and a formwork used therefor, according to a building such as a house.

  Conventionally, as a foundation structure for a building such as a house, for example, a technique disclosed in Japanese Utility Model Application Publication No. 3-22359 (Patent Document 1) or Patent No. 3179738 (Patent Document 2) is known. In this foundation structure for buildings, as shown in FIG. 9, a cloth foundation 100 is provided on the outer periphery, and a plurality of columnar support foundations 101 (also referred to as column foundations) are erected inside the cloth foundation 100. Is configured. A foundation (not shown) is installed on the cloth foundation 100 and the pillar foundation 101. As a result, (a) the ventilation property of the space under the floor can be improved, and the generation of molds can be suppressed to improve the durability of the building. (B) It is possible to widen the underfloor space, and to facilitate the construction and maintenance of underfloor piping and the like. (C) It has the advantage of being able to reduce the amount of formwork and the amount of concrete.

  The construction method of such a foundation for a building is described in the prior art, for example, in the above-mentioned Patent Document 2, and as shown in FIG. 10, an embedded type of foundation 100 for cloth foundation on the top of the footing 102 built beforehand. A formwork (not shown) is installed, and an embedded support form 103 (also referred to as a column formwork) for the support base 101 is installed inside the cloth base formwork. Subsequently, concrete is poured into the cloth foundation form and the column form 103 and cured. After curing, the fabric foundation form and the support form 103 are left as part of the structure to construct the fabric foundation 100 and the support foundation 101. The embedded cloth foundation form and the pillar form 103 are provided with a height adjustment mechanism (not shown) in order to adjust the height of the foundation.

Japanese Utility Model No. 3-22359 Patent No. 3179738 gazette

  By the way, in the pillar foundation 101 of the conventional foundation structure for a building, although formed in a cylindrical shape, it can not be said that the supporting strength of the foundation installed in this is necessarily good. In addition, in the construction method, since the embedded type support column 103 is used, there is a problem that the cost is increased. In particular, those equipped with a height adjustment mechanism are expensive. In order to solve this, it is conceivable to use a cylindrical support form (not shown) which can be used repeatedly, but since it is cylindrical, a large frictional resistance with the support occurs when the support form is removed. As a result, the workability of the construction becomes worse.

The present invention has been made in consideration of the above problems, improves the supporting strength of the base of the column foundation construction easily and to improve the construction workability, for buildings and allow inexpensive basic an object of the present invention is to provide a construction how.

  The foundation structure for a building according to the present invention for achieving such an object is a solid foundation made of concrete having horizontal reinforcements laid inside and concrete made erected on the outer periphery of the solid foundation. A plurality of concrete columns each having a cloth foundation and a standing reinforcing bar group erected at a predetermined position on the inner side of the cloth foundation and connected to the horizontal reinforcing bar group and connected to the solid foundation. A foundation is provided, and the support foundation is formed into a frustum shape by a support form frame whose internal space is formed into a frustum shape and removed after the formation. The frustum shape means the shape of a truncated pyramid such as a triangular frustum or a square frustum, or a truncated cone.

  According to this configuration, when the pillar foundation is constructed, the pillar formwork is installed at a predetermined position on the inner side of the cloth foundation, and concrete is cast on it, cured and solidified, then the pillar formwork is Remove. As a result, a pillar foundation having erected rebar groups inside is constructed on a solid foundation. In this case, since the support form is finally removed by molding, the support form can be formed in a relatively simple shape, and can be repeatedly used, so that the cost can be reduced. In addition, when removing the support form, since the support form is formed in a frustum shape in the internal space, it is easily removed from the support foundation, so that removal can be performed extremely easily. Workability can be improved. Furthermore, since the column formwork is removed, the height of the column foundation can be adjusted according to the amount of injected concrete, and there is no need to provide a height adjustment mechanism as in the past, so installation work is easier. Cost reduction can be achieved.

  And, since the constructed pillar foundation is formed in a frustum shape, it spreads toward the solid foundation, and the pressure from the foundation is widely transmitted to the solid foundation, so the stability is improved. , The support strength of the base can be greatly improved. In addition, since the pillar foundation has inside erected reinforcement bars connected and connected to the horizontal reinforcement group of the solid foundation, the bond strength with the solid foundation is strong and reinforcement is also strong. Also in this respect, the support strength of the base can be greatly improved. Furthermore, the air flow is smoother as compared to a cylindrical shape.

  And as needed, it is set as the structure which set internal angle (theta) with respect to the solid foundation of the outer surface of the said support | pillar to 65 degrees <= (theta) <= 85 degrees. Desirably, 70 ° ≦ θ ≦ 80 °. Within this range, support stability and air circulation can be reliably ensured.

  Moreover, the outer shape of the said standing installation rebar group is formed in the frustum shape substantially similar to the outer shape of the said support | pillar foundation as needed. The outer shape of the erected reinforcing bar group means an outer shape formed by being rotated about the vertical central axis of the erected reinforcing bar group. This makes it possible to equalize the so-called "fogging" of the outer side of the reinforcing bar group to the surface of the column foundation, and secure the strength of the column foundation.

  Furthermore, if necessary, a fixing anchor bolt having an external thread projecting from the upper surface of the support base and having a fixed anchor bolt for fixing the support installed on the support base is embedded in the support base. The anchor anchor bolt can be used to securely fix the base.

Further, according to the construction method of a foundation for a building of the present invention for achieving the above object, a concrete solid foundation having a laid horizontal reinforcement group inside and concrete erected on an outer peripheral portion of the solid foundation And a plurality of concrete reinforcing bars provided at a predetermined position on the inner side of the cloth foundation and connected to the horizontal reinforcing bar group and standing erected therein and continuously connected to the solid foundation The foundation for a building is constructed by constructing a foundation for a building which is formed into a frustum shape by a column formwork which is provided with a column foundation and the inner space is formed into a frustum shape and removed after formation. There,
Rebar group construction step of constructing the above horizontal rebar group and erection rebar group,
A solid foundation construction step of placing a concrete in a state in which the standing reinforcing steel group is exposed to the horizontal reinforcing steel group and constructing a solid foundation;
Cloth foundation construction process to construct cloth foundation around the above solid foundation,
After the above solid foundation construction process, a pillar foundation construction process of placing concrete on the erected rebar group exposed from the constructed solid foundation to construct a pillar foundation,
The pillar foundation construction process
A pillar formwork installation step of covering the erection reinforcement group in the interior space of the pillar formwork and installing the same on the solid foundation;
A forming step of casting concrete in the installed support form after the support form installation process to form a support foundation;
After the forming step, the step of removing the support form frame from the formed support foundation is provided.

  According to this configuration, when constructing the pillar foundation, the horizontal reinforcing bar group and the standing reinforcing bar group are constructed in the reinforcing bar group construction process, and the horizontal reinforcing bars are exposed in the solid foundation construction process. We cast concrete in group and build solid foundation. In the cloth foundation construction process, for example, reinforcing bars for the cloth foundation are provided in advance in the reinforcing bar group construction process, and after the solid foundation construction process, a formwork for the cloth foundation is installed and concrete is cast Once cured and solidified, remove the form and build a cloth foundation around the solid foundation. In the cloth foundation construction process, for example, a block-shaped cloth foundation is constructed on a solid foundation, or, as shown in the above-mentioned prior art, an embedded cloth foundation form for cloth foundation is placed on a solid foundation; A cloth foundation may be provided by an appropriate method, such as placing concrete on this cloth foundation formwork and constructing it.

  Then, in the column foundation construction process, concrete is cast on the erected reinforcing bar group exposed from the constructed solid foundation to construct a column foundation. In this case, first, in the supporting column form setting process, the supporting column formwork is placed on the solid foundation by covering the erection reinforcing steel group in the internal space thereof. Next, in a forming step, concrete is placed in the installed support form, and then the concrete is cured and solidified to form a support foundation. Finally, in the support form removal process, the support form is removed from the formed support foundation. As a result, a pillar foundation having erected rebar groups inside is constructed on a solid foundation. In this case, since the support form is finally removed by molding, the support form can be formed in a relatively simple shape, and can be repeatedly used, so that the cost can be reduced. In addition, when removing the support form, since the support form is formed in a frustum shape in the internal space, it is easily removed from the support foundation, so that removal can be performed extremely easily. Workability can be improved. Furthermore, since the column formwork is removed, the height of the column foundation can be adjusted according to the amount of injected concrete, and there is no need to provide a height adjustment mechanism as in the past, so installation work is easier. Cost reduction can be achieved.

  And, since the constructed pillar foundation is formed in a frustum shape, it spreads toward the solid foundation, and the pressure from the foundation is widely transmitted to the solid foundation, so the stability is improved. , The support strength of the base can be greatly improved. In addition, since the pillar foundation has inside erected reinforcement bars connected and connected to the horizontal reinforcement group of the solid foundation, the bond strength with the solid foundation is strong and reinforcement is also strong. Also in this respect, the support strength of the base can be greatly improved. Furthermore, the air flow is smoother as compared to a cylindrical shape.

In addition, if necessary, through holes in the vertical direction are formed in advance, and a pressing member is installed at the upper end of the support pillar so as to press the support pillar against the solid foundation, and the solid foundation A presser anchor bolt having a lower end portion to be embedded and a tip end portion having a male screw portion inserted through the through hole of the presser member, and a presser anchor bolt penetrated through the through hole of the pressing member Prepare a presser nut screwed to the male screw portion and tightened to press the support frame against the solid foundation side via the presser member,
In the reinforcing bar group construction step, the presser anchor bolt is installed so that the lower end portion thereof faces the horizontal reinforcing bar group and the tip end projects from the standing reinforcing bar group , and the axis of the presser anchor bolt is the above Install along the vertical central axis P of the column foundation,
In the column support frame installation step, the column support frame is placed on a solid foundation, and then the pressing member is inserted into the male screw portion of the presser anchor bolt through the through hole thereof to the upper end of the column support frame. After that, the press nut is screwed into the male screw portion of the presser anchor bolt and tightened, and the presser member presses the support form against the solid foundation.
In the support form removing process, before the support form is removed, the support nut and the support member are removed from the support anchor bolt.

  As a result, since the support form can be pressed against the solid foundation by this pressing member, when casting concrete in the installed support form in the forming process, the support form will not be shaken, and the concrete can be reliably made. It can be filled.

Furthermore, if necessary, an indicator nut indicating the upper surface position of the support base is screwed in advance to the male screw portion of the presser anchor bolt,
Prior to the forming step, the position adjustment of the indicator nut is performed to define the upper surface position of the support base by the indicator nut. The indicator nut can be locked as a so-called double nut by screwing a lock nut into the male screw portion.
Since the position adjustment of the indicator nut is performed by a simple operation of rotating the indicator nut, the installation work is easy and cost can be reduced. Thereby, since the upper surface position of the above-mentioned pillar foundation is specified by the index nut, when casting concrete in the forming step, it is sufficient to pour the concrete up to the position where the index nut is present. Support foundations of Moreover, since it is not necessary to provide a height adjustment mechanism like before, construction work is easy that much, and it can aim at cost reduction.

Furthermore, if necessary, it has a tip portion in which a male screw portion is embedded in the column foundation and made to project from the upper surface of the column foundation in advance, and the foundation installed on the column foundation is fixed Prepare a fixed anchor bolt for
Before the forming step, the fixed anchor bolt is installed so that the lower end side faces the erected reinforcing bar group and the tip end projects from the erected reinforcing bar group , and the fixed anchor bolt is the axis is the above Set a predetermined distance away from the vertical central axis P of the above pillar base on which the presser anchor bolt is installed,
After the support form removal process, a portion of the presser anchor bolt protruding from the upper surface of the support base is cut.
Thereby, since the presser anchor bolt which became unnecessary is cut | disconnected, a fixed anchor bolt can be provided in a suitable position, and versatility can be improved.

  In addition, in order to achieve the above object, a column formwork used in the method of installing a foundation for a building according to the present invention is a column formwork for forming the column foundation, and the internal space is formed in a frustum shape. It has composition. The post form can be formed into a relatively simple shape, and can be repeatedly used, so that the cost can be reduced. In addition, when removing the support form, since the support form is formed in a frustum shape in the internal space, it is easily removed from the support foundation, so that removal can be performed extremely easily. Workability can be improved. Furthermore, since the column formwork is removed, the height of the column foundation can be adjusted according to the amount of injected concrete, and there is no need to provide a height adjustment mechanism as in the past, so installation work is easier. Cost reduction can be achieved.

  In this case, it is effective that the wall thickness is constant and integrally formed in a tubular shape. The shape is extremely simple and, for example, it can be easily made of metal or hard resin, and the cost can be further reduced. Moreover, since the whole support | pillar formwork becomes a frustum shape, many can be piled up and conveyance and storage can be made easy.

  According to the present invention, when the pillar foundation is constructed, it is molded with the pillar form frame which is finally removed, so that the pillar form frame can be formed into a relatively simple shape, and repeated use Cost reduction can be achieved because it can be done. In addition, when removing the support form, since the support form is formed in a frustum shape in the internal space, it is easily removed from the support foundation, so that removal can be performed extremely easily. Workability can be improved. Furthermore, since the column formwork is removed, the height of the column foundation can be adjusted according to the amount of injected concrete, and there is no need to provide a height adjustment mechanism as in the past, so installation work is easier. Cost reduction can be achieved.

  And, since the constructed pillar foundation is formed in a frustum shape, it spreads toward the solid foundation, and the pressure from the foundation is widely transmitted to the solid foundation, so the stability is improved. , The support strength of the base can be greatly improved. In addition, since the pillar foundation has inside erected reinforcement bars connected and connected to the horizontal reinforcement group of the solid foundation, the bond strength with the solid foundation is strong and reinforcement is also strong. Also in this respect, the support strength of the base can be greatly improved. In addition, the air flow is smoother as compared to the cylindrical shape, and so on.

It is a perspective view showing a foundation for buildings concerning an embodiment of the invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a top view which shows the foundation structure for buildings which concerns on embodiment of this invention. It is a perspective view which shows the principal part of the foundation structure for buildings which concerns on embodiment of this invention in the state which installed the base. It is sectional drawing which shows the principal part of the foundation structure for buildings which concerns on embodiment of this invention. It is process drawing which shows the construction method of the foundation for buildings which concerns on embodiment of this invention. The support | pillar form frame which concerns on embodiment of this invention used by the construction method of the foundation for buildings which concerns on embodiment of this invention is shown, (a) is a perspective view, (b) is a top view, (c) is a front. FIG. The construction method of the foundation for buildings which concerns on embodiment of this invention WHEREIN: The state of the formation process of a support | pillar foundation construction process is shown, (a) is sectional drawing, (b) is a top view. It is a disassembled perspective view which shows the support | pillar form frame which concerns on another embodiment of this invention used by the construction method of the foundation for buildings which concerns on embodiment of this invention. It is a perspective view which shows an example of the conventional foundation structure for buildings. In the construction method of the foundation for buildings in the past, it is a sectional view showing the construction state of a pillar foundation.

Hereinafter, based on an accompanying drawing, a foundation structure for buildings, a construction method of a foundation for buildings, and a formwork used for the same according to an embodiment of the present invention will be described.
As shown in FIG. 1 to FIG. 4, the foundation structure K for a building according to the embodiment of the present invention includes a solid solid foundation 1 made of concrete having a horizontal rebar group 2 laid therein and an outer periphery of the solid foundation 1. A solid foundation 1 made of concrete erected on a part and a standing reinforcing steel group 11 erected at a predetermined position inside the textile foundation 3 and connected to the horizontal reinforcing steel group 2 inside the solid foundation 1 And a plurality of concrete support foundations 10 which are connected to each other.

  The column foundation 10 is formed in a frustum shape by a column formwork M (FIGS. 6 and 7) according to the embodiment of the present invention in which the internal space e is formed in a frustum shape and removed after molding. The frustum shape means the shape of a truncated pyramid such as a triangular frustum or a square frustum, or a truncated cone. In the embodiment, it is formed in a truncated cone shape. The column formwork M according to the embodiment of the present invention will be described later. Further, the internal angle θ with respect to the solid foundation 1 of the outer surface of the column foundation 10 is set to 65 ° ≦ θ ≦ 85 °. Desirably, 70 ° ≦ θ ≦ 80 °. In the embodiment, θ = 75 °. The height H of the pillar base 10 is set to H = 350 mm to 400 mm, and the diameter D of the bottom is set to D = 500 mm to 550 mm. In the embodiment, H = 380 mm and D = 530 mm are set. Furthermore, the outer shape of the erected reinforcing bar group 11 is formed in a frustum shape substantially similar to the outer shape of the support base 10. The outer shape of the erected reinforcing bar group 11 is an outer shape formed by being rotated about the vertical central axis P of the erected reinforcing bar group 11. As a result, the thickness T of the so-called "fogging" to the outer surface of the reinforcing bar group and the surface of the column base 10 can be equalized, and the strength of the column foundation 10 can be reliably ensured. It is set to T = 40 mm-60 mm.

  In addition, a fixed anchor bolt 20 is embedded in the column base 10 and has an external thread 21 projecting from the upper surface of the column base 10 for fixing a base B installed on the column base 10. The fixed anchor bolt 20 is provided at a position spaced apart from the vertical central axis P of the column foundation 10 by a predetermined distance. The fixing anchor bolt 20 can be used to securely fix the base B.

  Next, the construction method of the foundation for buildings according to the embodiment of the present invention will be described. The construction method of the foundation for a building according to the embodiment is to construct the foundation structure K for a building according to the above-mentioned embodiment as shown in FIG. 5 to FIG. 7, and in the embodiment of the present invention The pillar formwork M concerned is used.

As shown in FIG. 6 and FIG. 7, the column formwork M according to the embodiment of the present invention is to form the column foundation 10 described above, and the internal space e is formed in a frustum shape. The frustum shape means the shape of a truncated pyramid such as a triangular frustum or a square frustum, or a truncated cone. In the embodiment, it is formed in a truncated cone shape. Specifically, the column formwork M is made of a rigid resin such as vinyl chloride, and has a constant thickness t and is integrally formed in a tubular shape. The thickness t is set to t = 5 mm to 15 mm. In the embodiment, t = 12 mm is set.
The column formwork M has a relatively simple shape and can be used repeatedly, so that the cost can be reduced.

Further, in the method of constructing a foundation for a building according to the embodiment, as shown in FIG. 7, the pressing member 30, the pressing anchor bolt 31, the pressing nut 32, and the pressing washer 33 are prepared in advance. The pressing member 30 is a member made of a lumber of wood, having a vertical through-hole 34 formed thereon, and being a member mounted on the upper end of the column mold M for holding the column mold M against the solid foundation 1 . The presser anchor bolt 31 has a lower end portion embedded in the solid foundation 1 and a tip end portion which is inserted into the through hole 34 of the presser member 30 and in which a male screw portion 35 is formed. Further , the presser anchor bolt 31 is installed such that its axis is along the vertical central axis P of the column foundation 10. The presser nut 32 is screwed into the male screw portion 35 of the presser anchor bolt 31 penetrated through the through hole 34 of the presser member 30, tightened, and the support form frame M to the solid foundation 1 side through the presser member 30. Press. The presser washer 33 is interposed between the presser nut 32 and the presser member 30.

  In addition, an indicator nut 40 indicating the upper surface position of the support base 10 is screwed in advance to the male screw portion 35 of the presser anchor bolt 31. Further, a lock nut 41 for locking the indicator nut 40 is also screwed.

  Furthermore, in the construction method of the foundation for a building according to the embodiment, the fixed anchor bolt 20 for fixing the base B installed on the pillar base 10 is prepared in advance. The fixed anchor bolt 20 is embedded in the column base 10 and has a tip portion on which a male screw 21 is formed to be protruded from the upper surface of the column base 10.

  The construction method of the foundation for a building according to the embodiment is, as shown in the process chart of FIG. 5, a reinforcing bar group construction process (1), a solid foundation construction process (2), a cloth foundation construction process (3), a pillar foundation construction And (4). The column foundation construction process (4) includes a column mold installation process (4-1), a forming process (4-2), and a column mold removal process (4-3). Each step will be described below.

(1) Rebar Group Building Step As shown in FIG. 7 (a), the horizontal reinforcing bar group 2 and the standing reinforcing bar group 11 are constructed on the ground floor by laying gravel or the like. The upright reinforcing bar group 11 is connected to the horizontal reinforcing bar group 2 via a binding line (not shown). In addition, at this time, the lower end portion of the presser anchor bolt 31 faces the horizontal reinforcing bar group 2 and the tip end portion protrudes from the standing reinforcing bar group 11, so that the binding wire ( Connect and install via not shown. Further, the lower end portion side of the fixed anchor bolt 20 faces the erected reinforcing bar group 11 and the tip end portion is connected to the erected reinforcing bar group 11 via a binding wire (not shown) so that the tip projects from the erected reinforcing bar group 11 Wear and install. In addition, installation of the fixed anchor bolt 20 may be installed after the solid foundation construction process as long as it is before the molding process. In addition, reinforcing bars (not shown) for the cloth foundation 3 are connected to the horizontal reinforcing bar group 2 and set upright.

(2) Solid Foundation Construction Step Concrete is cast in the horizontal reinforcement group 2 with the erection reinforcement group 11 exposed and cured to solidify the concrete, and the solid foundation 1 is constructed.

(3) Cloth foundation construction process Construct cloth foundation 3 around solid foundation 1. After covering the reinforcing bar for the cloth foundation 3 and installing the formwork for the cloth foundation 3 and placing concrete on it, curing and curing it, remove the formwork and put the cloth foundation around the solid foundation 1 Build 3 In the cloth foundation construction step, for example, a block-shaped cloth foundation (not shown) is constructed on the solid foundation 1 or, as shown in the prior art, an embedded cloth foundation type for the cloth foundation 3 A frame (not shown) may be placed on the solid foundation 1 and the cloth foundation 3 may be provided by an appropriate method, such as placing concrete on this cloth foundation formwork and constructing. In addition, the cloth foundation construction process may be performed after the pillar foundation construction process, may be performed simultaneously, or may be appropriately performed.

(4) Strut Foundation Construction Step After the solid foundation construction step, concrete is cast on the erected reinforcing bar group 11 exposed from the constructed solid foundation 1 to construct a pillar foundation 10. Follow the steps below.

(4-1) Column form installation process As shown in FIG. 7, the column form M is placed on the solid foundation 1 by enclosing the erected reinforcing steel group 11 in the internal space e. First, the column formwork M is placed on the solid foundation 1, and then the holding member 30 is inserted through the through hole 34 into the male screw portion 35 of the anchor bolt 31 to bridge the upper end of the column formwork M. Thereafter, the presser nut 32 is screwed to the male screw portion 35 of the presser anchor bolt 31 via the presser washer 33 and tightened, and the presser member 30 presses the column form M against the solid foundation 1.

  In this state, the position adjustment of the indicator nut 40 is performed, and the indicator nut 40 defines the upper surface position of the support base 10. The index nut 40 is locked by the lock nut 41 screwed to the male screw portion 35. Since the position adjustment of the indicator nut 40 is performed by a simple operation of rotating the indicator nut 40, the installation work is easy and cost can be reduced. The position adjustment of the index nut 40 may be performed before installing the column formwork M, that is, it may be performed timely if it is before the forming process.

(4-2) Forming Step A concrete is cast in the installed column formwork M to form the column foundation 10. In this forming process, when casting concrete, the concrete is poured to a place where the index nut 40 is present. Level with a suitable iron. In this case, since the injection amount of concrete is determined by the position of the indicator nut 40 which defines the upper surface position of the column foundation 10, the column foundation 10 of the required height can be reliably constructed. For this reason, since it is not necessary to provide a height adjustment mechanism like before, construction work is easy that much, and cost reduction can be aimed at. In addition, since the column formwork M is pressed against the solid foundation 1 by the holding member 30, when casting concrete in the column formwork M, the column formwork M does not wobble and concrete is reliably It can be filled. Then cure and harden the concrete.

(4-3) Support form removing process The support form M is removed from the formed support base 10. In this case, first, the presser nut 32 is loosened, and the presser nut 32, the presser washer 33 and the presser member 30 are removed from the presser anchor bolt 31. In this state, the pillar formwork M is removed from the pillar base 10 and removed. When removing the column formwork M, the column formwork M has a very small frictional resistance because the internal space e is formed in a frustum shape, and the column formwork M is easily removed from the column foundation 10, and hence removal is extremely easy. The work efficiency can be improved accordingly. As a result, as shown in FIG. 4, a pillar foundation 10 having a standing reinforcing steel group 11 inside is constructed on the solid foundation 1.

  Then, after the support form removal process, as shown in FIG. 4, the portion of the presser anchor bolt 31 protruding from the upper surface of the support base 10 is cut. Thereby, only the fixed anchor bolt 20 projects from the upper surface of the column base 10. Since the presser anchor bolt 31 which has become unnecessary is cut, the fixed anchor bolt 20 can be provided at an appropriate position, and versatility can be improved.

In the foundation for a building thus constructed, as shown in FIG. 3, a foundation B of the building is installed to construct a building. In this case, since the fixed anchor bolt 20 is embedded in the column foundation 10, the base B can be securely fixed using the fixed anchor bolt 20.
And, since the constructed pillar foundation 10 is formed in a frustum shape, it spreads toward the solid foundation 1, and the pressure from the foundation B is transmitted to the solid foundation 1 in a wide range, so stability is achieved. Can be improved, and the support strength of the base B can be greatly improved. In addition, since the pillar foundation 10 has the erected reinforcing steel bar group 11 erected by being connected to the horizontal reinforcing steel bar group 2 of the solid foundation 1, the bond strength with the solid foundation 1 is strong, and reinforcement Also from this point of view, the supporting strength of the base B can be greatly improved. Furthermore, the air flow is smoother as compared to a cylindrical shape.

  Further, the internal angle θ with respect to the solid foundation 1 of the outer surface of the pillar base 10 is set to 65 ° ≦ θ ≦ 85 °, desirably 70 ° ≦ θ ≦ 80 °, and in the embodiment, θ = 75 °. Therefore, support stability and air circulation can be reliably ensured in this range. Furthermore, since the outer shape of the erected reinforcing bar group 11 is formed in a frustum shape substantially similar to the outer shape of the column foundation 10, it is said to be the so-called "fogging" The thickness can be made uniform, and the strength of the column base 10 can be reliably ensured.

  In the above embodiment, the column mold M is integrally formed in a cylindrical shape with a constant thickness t of a hard resin such as vinyl chloride, but the present invention is not necessarily limited thereto. For example, FIG. As shown in the above, it may be divided and formed by a metal plate or the like, and may be used in combination at the time of use, and may be appropriately changed. In addition, although the pillar formwork M and the pillar foundation 10 are formed in a truncated cone shape, the present invention is not necessarily limited to this, and may be formed in a truncated pyramid such as a triangular frustum or a square frustum. There is no excuse.

K Foundation structure for building M Formwork e Internal space 1 Solid foundation 2 Horizontal reinforcement group 3 Cloth foundation 10 Support foundation 11 Vertical reinforcement group P Vertical central axis 20 Fixing anchor bolt 21 Male thread 30 Holding member 31 Holding anchor bolt 32 Holding Nut 33 Presser washer 34 Through hole 35 Male thread 40 Index nut 41 Lock nut (1) Rebar group construction process (2) Solid foundation construction process (3) Cloth foundation construction process (4) Support foundation construction process (4-1) Support form installation process (4-2) Forming process (4-3) Support form removal process

Claims (2)

The concrete solid foundation having the horizontal rebar group laid inside, the concrete cloth foundation standing upright on the outer periphery of the solid foundation, and the horizontal reinforcement at a predetermined position inside the cloth foundation It is equipped with a plurality of concrete support pillars which have erected reinforcement bars connected in groups and erected and connected to the solid foundation inside, and the pillar foundation is formed into a frustum shape in the internal space A method of constructing a foundation for a building in which a foundation for a building formed into a frustum shape is formed by a support form which is removed after forming and
Rebar group construction step of constructing the above horizontal rebar group and erection rebar group,
A solid foundation construction step of placing a concrete in a state in which the standing reinforcing steel group is exposed to the horizontal reinforcing steel group and constructing a solid foundation;
Cloth foundation construction process to construct cloth foundation around the above solid foundation,
After the above solid foundation construction process, a pillar foundation construction process of placing concrete on the erected rebar group exposed from the constructed solid foundation to construct a pillar foundation,
The pillar foundation construction process
A pillar formwork installation step of covering the erection reinforcement group in the interior space of the pillar formwork and installing the same on the solid foundation;
A forming step of casting concrete in the installed support form after the support form installation process to form a support foundation;
And a post mold frame removing process for removing the post mold frame from the molded post foundation after the forming process .
A pressing member is formed in advance in the vertical direction through holes and is installed at the upper end of the column form frame to press the column form frame against the solid foundation, and a lower end portion embedded in the solid foundation And a screwing anchor bolt having a tip end portion having a male screw portion which is inserted into the through hole of the holding member and is screwed with a male screw portion of the holding anchor bolt penetrated through the through hole of the holding member. And prepare a presser nut which is tightened to press the support form against the solid foundation side via the presser member,
In the reinforcing bar group construction step, the presser anchor bolt is installed so that the lower end portion thereof faces the horizontal reinforcing bar group and the tip end projects from the standing reinforcing bar group, and the axis of the presser anchor bolt is the above Install along the vertical central axis P of the column foundation,
In the column support frame installation step, the column support frame is placed on a solid foundation, and then the pressing member is inserted into the male screw portion of the presser anchor bolt through the through hole thereof to the upper end of the column support frame. After that, the press nut is screwed into the male screw portion of the presser anchor bolt and tightened, and the presser member presses the support form against the solid foundation.
In the support form removing process, before removing the support form, the support nut and the support member are removed from the support anchor bolt,
A fixed anchor bolt for fixing a base to be installed on the pillar foundation, having a tip portion in which an external thread portion is formed in advance and embedded in the pillar foundation and made to project from the upper surface of the pillar foundation Prepare
Before the forming step, the fixed anchor bolt is installed so that the lower end side faces the erected reinforcing bar group and the tip end projects from the erected reinforcing bar group, and the fixed anchor bolt is the axis is the above Set a predetermined distance away from the vertical central axis P of the above pillar base on which the presser anchor bolt is installed,
A construction method of a foundation for a building characterized by cutting a portion of the presser anchor bolt protruding from the upper surface of the support base after the support frame removal process . An indicator nut indicating the upper surface position of the pillar base is screwed in advance to the male screw portion of the presser anchor bolt,
2. A method according to claim 1 , further comprising the step of adjusting the position of said indicator nut before said forming step, and defining the upper surface position of said support base by said indicator nut.

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