JP2000265477A - Reinforcing method and reinforcing structure for building footing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reinforce a footing rising part without cutter work, and to cope with not only a long-term load but also a short-term load by fixing a reinforcing material to the side surface upper side of the rising part. SOLUTION: A carbon fiber sheet 11 for a long-term load is fixed to the side surface upper side of a rising part La of a continuous footing L by an adhesive. Then, stress not less than a difference between tensile strength possessed by the rising part La and tensile stress generated on the upper side of the rising part La increased by an enlargement is borne by the sheet 11. Next, when a horizontal load acts on a bearing wall W of an opening part X, upward vertical force acts on the left end of the wall W and the right end of the opening part X. The bending moment also increases in the footing L according to an increase by fastening the wall W and the footing L. Then, a carbon fiber sheet 12 for a short-term load is adhered to the inside surface lower side of the rising part La in a part of hole down hardware 40. Next, the sheet 12 is also adhered to a part of hardware 41. Thus, a building footing can be easily and efficiently reinforced by fastening a sill and the footing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foundation of a building, and more particularly to a method and a structure for reinforcing a foundation of a building for the purpose of strengthening the foundation of an existing wooden building.

[0002]

2. Description of the Related Art In recent years, the revision of the Building Standard Law and the like has made it possible to construct a wooden three-story house. However, when constructing a wooden three-story house by extension, unlike the case of a new construction, it is necessary to reinforce the existing two-story foundation to conform to the three-story standard.

[0003] As a conventional technique of such foundation reinforcement, for example, Japanese Patent Application No. 8-34467 (Japanese Unexamined Patent Application Publication No. 10-1689).
No. 02 publication). This is because, as shown in FIG. 7, in order to cope with an increase in bending stress (in the direction of the arrow) acting on the cloth foundation L, the tensile strength of the rising part La of the cloth foundation L is increased. A long rod-shaped reinforcing material r is embedded in a concave portion p formed on the upper side surface.

[0004]

However, in the above-mentioned prior art, the drilling of the recess p in the rising portion La is a manual operation using a cutter or the like, so that it takes a great deal of time. In particular, this problem is serious because the worker must work under the floor.

[0005] Further, the above-mentioned prior art deals with an increase in a long-term vertical load such as a fixed load and a load, but can deal with an increase in a short-term horizontal load such as an earthquake load. Not something.

[0006] In view of the above problems, the present invention can reinforce the rising portion of the foundation without complicated cutter work.
It is an object of the present invention to provide a method of reinforcing a building foundation and a reinforcing structure that can handle not only long-term loads but also short-term loads.

[0007]

That is, the invention according to claim 1 is a method for reinforcing a cloth foundation comprising a horizontal footing portion and a vertical rising portion, wherein a reinforcing material is provided on an upper side surface of the rising portion. Is a method of reinforcing a building foundation characterized by fixing, in a cloth foundation comprising a horizontal footing part and a vertical rising part,
A reinforcing structure for a building foundation, wherein a reinforcing material is fixed to an upper side surface of the rising portion.

According to such a reinforcing method and a reinforcing structure, a reinforcing material having a predetermined length is simply fixed to the upper side surface of the rising portion without drilling a recess in the rising portion with a cutter or the like, and the method is simple and efficient. The foundation can be reinforced. The reinforcing method and the reinforcing structure are intended to cope with an increase in a long-term vertical load such as a fixed load or a loaded load, similarly to the above-described conventional technology.

The invention according to claim 3 is a method for reinforcing a cloth foundation comprising a horizontal footing portion and a vertical rising portion, wherein the rising portion and a base above the rising portion are tightly joined to each other. A method for reinforcing a building foundation characterized by being integrated, wherein the invention according to claim 4 is a cloth foundation comprising a horizontal footing part and a vertical rising part, wherein the rising part and a base thereabove. Is a reinforcing structure for a building foundation characterized by being tied together.

[0010] The reinforcing method and the reinforcing structure utilize the bending strength of the existing base. For example, the rising part and the base can be connected to each other without drilling a recess in the rising part with a cutter or the like. Tightening with a stainless steel plate or the like to integrate them together allows the existing foundation to bear the insufficient amount of tensile stress to be borne by the rising portion, and can easily and efficiently reinforce the building foundation. The reinforcing method and the reinforcing structure are intended to cope with an increase in a long-term vertical load such as a fixed load or a load, similarly to the first or second aspect of the present invention. .

According to a fifth aspect of the present invention, there is provided a method of reinforcing a cloth foundation comprising a horizontal footing portion and a vertical rising portion, wherein the end of the load-bearing wall to which an upward vertical load is applied is connected to the load-bearing wall. The lower side of the rising portion is connected to the side surface of the cloth foundation with a connecting hardware. Of such connecting portions located at the corners of the cloth foundation, the lower portion extends from the connecting portion to the end of the load-bearing wall adjacent thereto. A reinforcing material is fixed to the lower side surface of the rising portion, and a reinforcing material is provided on the upper side surface of the lower rising portion so that the connecting portion other than the connecting portion straddles the left and right sides of the connecting portion in side view. A method for reinforcing a building foundation, characterized in that a fixed portion or a rising portion below the fixed portion and a base above the fixed portion are fixed to each other by a reinforcing material, and the two are integrated. Standing perpendicular to the footing In cloth foundation consisting of Ri part,
Regarding the end of the load-bearing wall on which an upward vertical load is applied, a connecting hardware for connecting the load-bearing wall and a side surface of a rising portion below the load-bearing wall, and a connecting portion located at a corner of the cloth base among such connecting portions, From the connecting portion to the end of the bearing wall adjacent to the connecting portion, the reinforcing material fixed to the lower side of the rising portion below the connecting portion, and the connecting portion other than the connecting portion, straddling the left and right sides of the connecting portion in a side view. Thus, a reinforcing member fixed to the upper side surface of the lower rising portion or a reinforcing member fixed to both the lower rising portion and the base so as to integrate the lower rising portion with the base above the lower rising portion is provided. This is the reinforcement structure of the building foundation. Note that the term “load-bearing wall end” here is a concept that includes both ends of the opening in a load-bearing wall having an opening.

According to the reinforcing method and the reinforcing structure, it is possible to cope with an increase in a short-term horizontal load such as an earthquake load without forming a recess in a rising portion with a cutter or the like. That is, when the building weight increases due to the extension, the end of the load-bearing wall on which the vertical load acts is connected to the cloth foundation in order to prevent the lifting of the load-bearing wall due to an increase in the horizontal load. The bending moment acting on the fabric foundation via the simple connection increases. Specifically, the tensile load acting on the lower side of the rising portion increases at the connecting portion located at the corner portion of the cloth foundation, and the tensile load acting on the upper side of the rising portion increases at the other connecting portions. Will increase. Therefore, by separating the connecting portion depending on whether the tensile load increases above or below the rising portion, and by fixing the reinforcing material on the upper side surface or the lower side surface of the rising portion, respectively, easily and efficiently. The fabric foundation can be reinforced.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Loads acting on buildings are broadly classified into long-term loads such as fixed loads and loading loads, and short-term loads such as seismic force and wind pressure. When the building is expanded, the weight of the building increases, so that both the long-term load and the short-term load acting on the cloth foundation increase, and it is necessary to reinforce the cloth foundation accordingly. Thus, FIG. 1 shows a state in which both the long-term load countermeasure and the short-term load countermeasure are applied to one cloth foundation. In the following, in order to explain the contents of FIG. 1, the long-term load countermeasures and the short-term load countermeasures will be described separately, and then the relationship between them will be described. In the description, the same elements will be denoted by the same reference symbols, without redundant description.

1. Long-term load measures Long-term loads are mainly vertical loads, for example, Fig. 2 (a)
As shown in FIG.
When weight acts, mechanically as shown in FIG.
Considering the cloth foundation L below the load-bearing wall W as a four-point support beam
It can be considered that an evenly distributed vertical load acts on this.
Wear. Then, the distribution of bending moment generated in this beam is shown.
FIG. 2 (c) shows the state where the maximum bending was performed just below the opening X.
Moment _LM has occurred. Therefore, concre
Consider that materials are inherently vulnerable to tension
And the long-term bending stress that occurs in the fabric foundation when building is added
To make up for the shortage of
It is necessary to supplement the tensile strength above the rising part of the fabric foundation.
You. The long-term load countermeasure of the present invention is based on this concept.
Along the upper side of the rising portion La
Means (means 1) for fixing the base and the existing base 20 have
In order to utilize the tensile strength, the base 20 and the rising portion La are tightly connected.
There is a means (means 2) for connecting the two together.

<Means 1> FIG. 3 (a) is a perspective view showing an embodiment of a reinforcing method or a reinforcing structure for a building foundation according to the present invention in which measures against a long-term load are taken, and FIG. It is a principal part longitudinal cross-sectional view. Here, the symbol Lb is the cloth foundation L
Reference numeral 11 indicates a carbon fiber sheet for long-term load as a reinforcing material.

As shown in FIG. 1, the rising portion L of the cloth foundation L
The carbon fiber sheet 11 for long-term load is fixed to the upper side of the side surface a by using an adhesive without forming a recess with a cutter or the like. Here, the use of carbon fiber as a reinforcing material not only satisfies the structurally necessary conditions of high tensile strength and small elongation under tensile load, but also is excellent in that it is light and deformable. Because it is a material. Therefore, as a reinforcing material instead of the carbon fiber sheet 11 for long-term load, a sheet material made of a material such as glass fiber or aramid fiber which satisfies the same conditions can be used.

Further, the reason why the carbon fiber sheet 11 for long-term load is fixed to the upper side surface of the rising portion La is that the maximum bending moment _LM is generated above the rising portion La as described above. Here, in the present embodiment, the long-term load carbon fiber sheet 11 is fixed over the entire length of the rising portion La, but the present invention is not limited to this, and the necessary long-term load carbon fiber sheet is required. 11
May be calculated by structural calculation, and the carbon fiber sheet 11 for long-term load having the area or more may be used (see FIG. 1). Then, when applied to the cloth foundation L below the load-bearing wall W having the opening X, the carbon fiber sheet 11 for a long-term load at this time is formed on the upper side surface of the rising portion La, It is fixed to the left and right with the center immediately below the part X as the center.

In this embodiment, the rising portion L
The carbon fiber sheet for long-term load 11 is fixed to both side surfaces of the carbon fiber sheet 11 for long-term load, but the present invention is not limited to this.
May be fixed. In this case, it is desirable that the long-term load carbon fiber sheet 11 be fixed to the inner surface of the rising portion La. This is because if it is fixed to the outer side surface of the rising portion La, it may be difficult to settle down in relation to the exterior finish or the like. The adhesive used here must be capable of firmly fixing the long-term load carbon fiber sheet 11 to the side surface of the rising portion La, and the adhesive strength must be long. Desirably, the material strength exceeds the material strength of concrete or concrete, such as an epoxy resin, a polyimide resin, or a urethane resin.

In such a method or structure for reinforcing a foundation of a building, the difference between the tensile strength originally possessed by the rising portion La and the tensile stress generated above the rising portion La that has been increased by the extension is at least as large as the difference between the tensile strength and the tensile stress. Since the long-term load carbon fiber sheet 11 (including the adhesive) bears the stress, the long-term load carbon fiber sheet 11 can compensate for the insufficient strength of the rising portion La and efficiently reinforce the existing cloth foundation L. it can.

The underfloor ventilation notch Lc is shown in the drawing, but the carbon fiber sheet 11 for long-term load is fixed to the rising portion La at the underfloor ventilation notch Lc. Of course, it is not necessary. The fabric foundation to be reinforced according to the present invention is not necessarily a notch L for underfloor ventilation.
It is not necessary that the cutout Lc be provided, for example, by using a base receiving plate (see Japanese Patent Application Laid-Open No. 10-237877) to eliminate the underfloor ventilation notch Lc.

<Means 2> FIG. 4 (a) is a perspective view showing another embodiment of a method of reinforcing a building foundation or a reinforcing structure according to the present invention in which a long-term load countermeasure is taken.
Is a longitudinal sectional view of the main part. Here, reference numeral 20 denotes an existing base, and reference numeral 30 denotes a stainless steel plate.

As shown in FIG.
a is tightly connected to the base 20 by the stainless steel plate 30 without forming a recess with a cutter or the like, and both are integrated. The term "integration" as used herein means that both members behave as a single beam with respect to bending load, for which a predetermined shear force is transmitted between them. is necessary.

Therefore, in the present embodiment, the stainless steel plate 30 bent so as to have a crank sectional shape is fixed with a predetermined adhesive along the upper side surface of the rising portion La and the side surface of the base 20. , Rising part La and base 2
It is configured such that a predetermined shearing force is transmitted between zero. Here, the use of the stainless steel plate 30 for binding the rising portion La and the base 20 not only satisfies the structurally necessary condition that the tensile strength is large and the elongation with respect to the tensile load is small, but also Because it is light and easy to bend. Therefore, in place of the stainless steel plate 30, a sheet material made of a material such as carbon fiber, glass fiber, and aramid fiber that satisfies the same conditions can be used. Further, as the adhesive, an epoxy-based resin, a polyimide-based resin, a urethane-based resin, or the like is used, and the performance required for these is the same as in the case of <Means 1> described above.

Further, in this embodiment, the stainless steel plate 30 is fixed over the entire length of the rising portion La, but as described above, the stainless steel plate 30 applies a predetermined shearing force between the rising portion La and the base 20. Since it is for transmission, if the safety can be confirmed by the structural calculation, the stainless steel plate 30 should be fixed only to the portion where the shearing force is maximum, that is, the fulcrum B and the fulcrum C shown in FIG. 2 (c). (See FIG. 1). In the present embodiment, the stainless steel plate 30 is fixed to the rising portion La and the inner surface of the base 20. However, the present invention is not limited to this, and the rising plate La is fixed to the outer surface or both side surfaces of the base 20. May be done. In addition, if the rising portion La and the base 20 can be tied together and the two can be integrated, there is no need to employ a means of fixing the stainless steel plate 30 with an adhesive as shown in the present embodiment, and an appropriate design can be adopted. Changes are possible.

When the rising portion La and the base 20 are thus tightly joined and integrated, the tensile strength originally possessed by the rising portion La and the upper portion of the rising portion La which has been increased by the extension are increased. Since the existing base 20 bears a stress greater than or equal to the generated tensile stress, the existing fabric foundation L can be efficiently reinforced.

As in the case of <Means 1>, a notch Lc for underfloor ventilation is shown in the figure, but the stainless steel plate 30 is attached to the rising portion La at the notch Lc for underfloor ventilation. Needless to say, there is no need to fix. The cloth base to be reinforced according to the present invention does not necessarily have to have the notch Lc for underfloor ventilation. For example, the cloth foundation for underfloor ventilation is provided by using a base receiving plate (see Japanese Patent Application Laid-Open No. 10-237877). It may be such that the notch Lc is eliminated.

2. Short-term load measures The short-term load is mainly horizontal load, for example, as shown in FIG.
When a rightward horizontal load is applied to the load-bearing wall W having the opening X as shown in FIG. 5B, the cloth foundation below the load-bearing wall W is mechanically supported at three points as shown in FIG. Therefore, it can be considered that an upward vertical load acts on the free end A. Since a fulcrum reaction force is generated upward at the fulcrum C of the beam, the left end of the load-bearing wall W and the opening X
It can be seen that an upward vertical force acts to lift the load-bearing wall W from the cloth foundation L at the right end. Therefore,
Since such an upward vertical force increases with an increase in the building weight due to the extension, the load-bearing wall W and the cloth foundation L are placed at the left end (fulcrum A) of the load-bearing wall W and the right end (fulcrum C) of the opening X.
And it is necessary to prevent the bearing wall W from rising.

FIG. 5 (c) showing the bending moment distribution of the beam shown in FIG.
It can be seen that a positive bending moment is acting on and a negative bending moment is acting on the fulcrum C. Therefore, since the load-bearing wall W and the cloth foundation L are tied to each other, the bending moment acting on the cloth foundation L increases with the increase in the building weight due to the extension, and therefore, it is considered that concrete is originally a material which is originally vulnerable to tension. Then, it is necessary to complement the tensile strength below the rising portion La from the fulcrum A to the fulcrum B with the tensile strength above the rising portion La for the fulcrum C.

The fulcrum A corresponds to a corner when the building is viewed in plan. Further, the bearing wall W is because it is divided by the opening X, the right end of the opening X can be said that the left edge of the bearing wall W _2. Therefore, "from the left end of the load-bearing wall W (fulcrum A) to the left end of the opening X (fulcrum B)
To over "means," bearing walls W _1, W bearing wall W ₁ for the lifting of the _anti-2, W ₂ and cloth basic L and a connecting portion that Tightened the (fulcrum A, the fulcrum C) corner of the fabric foundation L of those located in the section for (fulcrum a), it is possible that the ends of the shear wall W ₁ adjacent thereto from the connecting portion (fulcrum a) over the (fulcrum B) ". Similarly, "About the right end of the opening X"
Means that the connecting portions (fulcrum A and fulcrum C) of the load bearing walls W ₁ , W ₂ and the cloth foundation L other than the corners of the cloth foundation L in order to prevent the bearing walls W ₁ , W ₂ from rising. (The fulcrum C). "

Based on the above concept, a short-term load countermeasure for the cloth foundation L will be described with reference to FIG. FIG. 1 is a perspective view illustrating an embodiment of a method for reinforcing a building foundation or a reinforcing structure according to the present invention in which a short-term load measure is taken. Here, reference numeral 21 is a lateral joist, and reference numerals 40 and 41 are used.
Is a hole-down metal member which is a connecting metal member for connecting the rising portion La and the bearing wall W.

As shown in the drawing, the portion of the hole-down hardware 40 located at the corner of the cloth foundation L
From the corner to the end of the adjacent load-bearing wall, the short-term load carbon fiber sheet 12
Is glued. And about the site | part of the hole-down hardware 41 which is not located in the corner of the cloth foundation L, it straddles this right and left so that this hole-down hardware 41 may be straddled in side view,
The short-term load carbon fiber sheet 12 is bonded so that the upper side of the inner surface of the rising portion La therebelow and the inner surface of the base 20 are tightly connected. The bonding position of the short-term load carbon fiber sheet 12 is the same as that of <means 2> described in the long-term load countermeasures. However, for the portion of the hole-down hardware 41, the same mode as in <Means 1> may be adopted. That is, the hole-down metal part 41 reinforces the upper side surface of the rising portion La therebelow.
The concept is the same as the long-term load measures described above. In this case, the hole down hardware 4
Although 0 and 41 are attached to the outside of the rising portion La and the carbon fiber sheet 12 for short-term load is attached to the inside of the rising portion La, in the present invention, both may be attached to the opposite sides, or the same side surface may be used. It may be attached to.

3. Relationship between long-term load measures and short-term load measures It is necessary to note that the long-term load measures and short-term load measures described above can be performed separately and independently. That is, as a result of verification by structural calculation, it may be sufficient to take only long-term load countermeasures, or it may be sufficient to take only short-term load countermeasures. FIG.
As shown in Figure 2, it may be necessary to take both long-term and short-term load measures. In FIG. 1, attention must be paid to the parts of the hole-down hardware 41 which are different from those in other figures.

[0033]

As described above, according to the method for reinforcing a building foundation and the reinforcing structure according to the present invention, a side face of the rising portion can be obtained without forming a recess in the rising portion with a cutter or the like as in the prior art. Simple and efficient reinforcement of the building foundation by fixing a reinforcing material of a predetermined length to the base or by tying the foundation to the foundation using the bending strength of the existing foundation And can handle short-term loads as well as long-term loads.

[Brief description of the drawings]

FIG. 1A is a side view showing an embodiment of a method for reinforcing a building foundation or a reinforcing structure according to the present invention, in which both measures against a long-term load and measures against a short-term load are applied.

FIGS. 2A and 2B are diagrams for explaining the concept of a long-term load countermeasure in the present invention. FIG. 2A shows a state in which a long-term equally distributed vertical load acts on a load-bearing wall, and FIG. Shows a beam to model the stress state of the fabric foundation,
(C) shows the distribution of the bending moment generated in the beam.

FIG. 3A is a perspective view showing an embodiment of a method for reinforcing a building foundation or a reinforcing structure according to the present invention in which a long-term load countermeasure is applied, and FIG. It is.

FIG. 4 (a) is a perspective view showing another embodiment of a method for reinforcing a building foundation or a reinforcing structure according to the present invention in which a long-term load countermeasure is taken, and FIG. FIG.

5A and 5B are diagrams for explaining the concept of a short-term load countermeasure in the present invention. FIG. 5A shows a state in which a short-term horizontal load is applied to a load-bearing wall, and FIG. 5B shows a cloth foundation below the load-bearing wall. 3A and 3B show a beam for modeling the stress state of FIG.

FIG. 6 is a perspective view illustrating an embodiment of a method for reinforcing a building foundation or a reinforcing structure according to the present invention, in which measures against short-term load are applied.

7A is a perspective view showing a conventional method of reinforcing a building foundation or a reinforcing structure, and FIG. 7B is a longitudinal sectional view of a main part thereof.

[Explanation of symbols]

 L ... cloth foundation La ... rising part Lb ... footing part Lc ... notch for underfloor ventilation W ... load-bearing wall X ... opening p ... recess r ... rod-shaped reinforcing material 11 ... carbon fiber sheet for long-term load (reinforcing material) 12 … Carbon fiber sheet (reinforcing material) for short-term load 20… base 21… side joist 30… stainless steel plate 40, 41… hole down metal fittings

Claims (6)

[Claims] 1. A method for reinforcing a fabric foundation comprising a horizontal footing portion and a vertical rising portion, wherein a reinforcing material is fixed to an upper side surface of the rising portion. . 2. A reinforcing structure for a building foundation, wherein a reinforcing material is fixed to an upper side surface of the rising portion in a cloth foundation including a horizontal footing portion and a vertical rising portion. 3. A method of reinforcing a fabric foundation comprising a horizontal footing portion and a vertical rising portion, wherein the rising portion and a base above the rising portion are integrated to integrate them. How to reinforce building foundations. 4. A reinforcement for a building foundation, comprising: a cloth foundation having a horizontal footing portion and a vertical rising portion, wherein the rising portion and a base above the rising portion are integrated to be integrated with each other. Construction. 5. A method for reinforcing a fabric foundation comprising a horizontal footing portion and a vertical rising portion, wherein a load-bearing wall end on which an upward vertical load acts is provided with the load-bearing wall and a side surface of the lower rising portion. And a connecting hardware, and among such connecting portions, those located at the corners of the cloth foundation, from the connecting portion to the end of the load-bearing wall adjacent thereto, on the lower side surface of the rising portion below the connecting portion. A reinforcing member is fixed, and a reinforcing member is fixed to an upper side of a lower rising portion or a rising portion below the connecting portion other than the connecting portion so as to straddle right and left of the connecting portion in a side view. A method of reinforcing a building foundation, characterized in that a reinforcing material is fixed to a base above the base and the two are integrated. 6. A fabric base comprising a horizontal footing portion and a vertical rising portion, wherein a connecting hardware for connecting the bearing wall and a side surface of the rising portion below the bearing wall to which an upward vertical load is applied. Of such connecting portions, those located at the corners of the cloth foundation, from the connecting portion to the end of the load-bearing wall adjacent thereto, a reinforcing material fixed to the lower side surface of the lower rising portion, For the connecting portion other than the connecting portion, so as to straddle the left and right sides of the connecting portion in a side view, the reinforcing material fixed to the upper side surface of the lower rising portion or the lower rising portion and the base above it. And a reinforcing material fixed to the both so as to integrate the two.