JP7517164B2 - Formwork for slab foundation and its construction method - Google Patents

Description

The present invention relates to a formwork for a continuous foundation and a construction method thereof.

Patent Document 1 describes a formwork for a slab foundation. The procedure for constructing the formwork in Patent Document 1 is as follows. First, a multipurpose trapezoidal spacer is placed on the compacted ground. Next, a thin plate base formwork is placed on top of the multipurpose trapezoidal spacer in parallel with the foundation reinforcement.

JP 2003-268781 A

However, because thin plate base formwork is already folded when shipped from the factory, it takes up a lot of space in transport vehicles and at construction sites. Also, while thin plate base formwork makes it easy to adjust the length of the footing in a slab foundation, it is not possible to adjust its width. Therefore, to obtain a footing ground pressure that corresponds to the bearing capacity of the ground, it is necessary to manufacture thin plate base formwork for each footing width.

The present invention was made in consideration of the above-mentioned circumstances, and its purpose is to provide a formwork for a continuous footing that does not require a large amount of footing formwork and that allows the footing's ground pressure to be adjusted according to the bearing capacity of the ground, and a construction method for the same.

(1) The formwork for a slab footing according to the present invention comprises a base, a rising formwork supported by the base, a bendable flat footing formwork, and guide members extending to both sides from the base. The footing formwork is curved so as to bulge upwards, with its upper end fixed to the base or the rising formwork and its lower end fixed to the guide members.

With the above configuration, the dimensions of the footing can be changed at the fixed position of the guide member of the footing formwork. The footing formwork is flat and not bulky.

(2) The guide member has multiple through holes arranged along the extension direction for fixing the lower end of the footing formwork.

With the above configuration, the dimensions of the footing can be easily determined based on the position of the through holes.

(3) Marks indicating multiple fixing positions corresponding to the multiple through holes of the guide member are provided on the lower end of the footing formwork.

The above configuration allows the dimensions of the completed footing to be appropriate. This eliminates waste of fresh concrete and allows the area of the bottom end of the footing to be appropriate. In addition, footings of various shapes can be constructed using a single footing formwork.

(4) The upper end of the footing formwork is located between the base and the rising formwork.

According to the above configuration, the upper end of the footing formwork is sandwiched between the base and the rising formwork, so the footing formwork is less likely to separate from the base. This prevents the fresh concrete from leaking out of the upper end of the footing formwork due to the pressure of the fresh concrete when it is poured.

(5) The footing formwork is made of steel and is buried in the ground together with the slab.

With the above configuration, the footing formwork will eventually turn into iron sand even if it is left buried. In other words, the footing formwork does not impose a burden on the environment.

(6) The method for constructing the formwork for a slab footing of the present invention involves placing a base on the foundation, extending guide members to both sides from the base, curving the flat footing formwork so that it bulges upward, fixing the upper end of the footing formwork to the base, and fixing the lower end of the footing formwork to the guide members, and placing the riser formwork on the base.

According to the above construction method, the footing formwork is not bulky and can be easily transported to the construction site. In addition, a single type of footing formwork can be used to create formwork with a variety of footing dimensions.

(7) In the above construction method, the upper end of the footing formwork is sandwiched between the base and the rising formwork.

The present invention provides a formwork for a continuous footing that is not bulky and allows the footing's ground pressure to be adjusted according to the bearing capacity of the ground, and a construction method for the same.

Schematic diagram showing the state before assembly of the formwork 100 for a slab foundation. 3A and 3B are front and plan views of the base 110. FIG. 1 is a perspective view of a footing formwork 140. Schematic diagram showing the assembled state of the formwork 100 for the slab foundation. Schematic diagram showing a footing formwork 140 fixed to a guide member 120. FIG.

The following describes an embodiment of the present invention. This embodiment is merely one example of the present invention, and it goes without saying that it can be modified as appropriate without departing from the spirit of the present invention.

[Stretching direction X, width direction Y, height direction Z]
In each figure, mutually orthogonal arrows X, Y, and Z are shown. Arrow X indicates the extension direction X in which the completed slab will extend. Arrows Y and Z indicate the width direction Y and height direction Z of the completed slab. The width direction Y indicates the left-right direction when a person's viewing direction is aligned with the extension direction X, and is also the extension direction in which the guide member 120 extends from the base 110.

[Configuration of the formwork 100 for the strip foundation]
1 and 4, a formwork for a slab footing (hereinafter also simply referred to as a "formwork") 100 is assembled at a construction site of a house. The formwork 100 is installed at a foundation top 200 (see FIG. 4) and is used when pouring concrete for the slab footing. The slab footing has a footing portion and a rising portion.

In detail, the formwork 100 comprises a plurality of bases 110, a plurality of pairs of guide members 120, a plurality of rising formworks 130, and a plurality of footing formworks 140.

[Base 110]
1, each base 110 is a resin molded product having the same thickness as the other bases 110. Each base 110 has a small thickness in the extension direction X. In detail, the dimension of each base 110 in the extension direction X is sufficiently smaller than the dimension of the footing formwork 140 in the extension direction X.

2(A) and 2(B) are a front view and a plan view of each base 110. In FIG. 2, each base 110 has end faces 111B, 111T and side faces 111L, 111R. The end faces 111B, 111T are the lower end face and the upper end face of the base 110, and are parallel and flat to each other. The end face 111B contacts the ground work top end 200 (see FIG. 4) when the base 110 is placed on the ground work top end 200. Two rising formwork pieces 130 (see FIG. 4) are placed on the end face 111T. The end face 111T supports the two rising formwork pieces 130 from below.

Each base 110 has protrusions 112L, 112R. Protrusions 112L, 112R are thin plate-like in the height direction Z. Protrusion 112L protrudes leftward from the upper left corner of base 110. The upper end face of protrusion 112L is flush with end face 111T (i.e., parallel with no step). Protrusion 112R protrudes rightward from the upper right corner of base 110 and has a shape symmetrical to protrusion 112L.

Nails 150 are driven into the protrusions 112L and 112R to secure the footing formwork 140 (see FIG. 4) during assembly of the formwork 100. A triangular rib 113L is provided between the protrusion 112L and the side surface 111L for reinforcement. A triangular rib 113R is provided between the protrusion 112R and the side surface 111R.

[Guide member 120]
Each base 110 has a pair of guide members 120. The pair of guide members 120 has guide members 120L and 120R. The guide members 120L and 120R are resin molded products and are integrated with the base 110. The guide member 120L extends leftward from the lower left corner of the base 110. The guide member 120R extends rightward from the lower right corner of the base 110. Each of the guide members 120L and 120R is thin in the height direction Z and has a rectangular shape that is elongated in the width direction Y in a plan view. In addition, the lower end surface of each of the guide members 120L and 120R is flush with the end surface 111B.

Each guide member 120L, 120R has a number of through holes 121 arranged along the width direction Y for fixing the lower end of the footing formwork 140. In this embodiment, the multiple through holes 121 include through holes 121A to 121C. Through holes 121A, 121B, 121C are formed at positions where the footing widths are, for example, 410 mm, 520 mm, and 600 mm, respectively.

[Rising formwork 130, footing formwork 140]
Each rising formwork 130 is a formwork for a rising portion, and is made of a metal such as stainless steel or iron. Each rising formwork 130 has a substantially rectangular shape that is long in the extension direction X. In detail, each rising formwork 130 has a flat plate 131, a plurality of vertical ribs 132, and a plurality of horizontal ribs 133. The flat plate 131 has a substantially rectangular shape that extends in the extension direction X and the height direction Z and is long in the extension direction X. The plurality of vertical ribs 132 and the plurality of horizontal ribs 133 are arranged in a lattice pattern on one main surface of the flat plate 131. In detail, the plurality of vertical ribs 132 extend in the height direction Z and are arranged at intervals in the extension direction X. The plurality of horizontal ribs 133 extend in the extension direction X and are arranged at intervals in the height direction Z.

As shown in Figures 1 and 3, before the assembly of the formwork 100, each footing formwork 140 is a thin, flat iron plate that is elastically deformed by bending forces applied from the outside. Each footing formwork 140 has two rectangular main surfaces 141A and 141B. A plurality of marks 142 and a mark 143 are marked on the main surface 141A. Each mark 142 and 143 is a line that is parallel to each long side of the main surface 141A. Each mark 142 is marked on the main surface 141A at a position close to one long side. Here, the one long side is a side that substantially contacts the foundation top end 200 after the assembly of the formwork 100. The mark 143 is marked on the main surface 141A at a position close to the other long side. The other long side is a side that substantially contacts the base 110 after the assembly of the formwork 100.

In this embodiment, the multiple marks 142 are three marks 142A to 142C. The marks 142A to 142C are marked at positions on the main surface 141A that correspond to the through holes 121A to 121C (see FIG. 2), respectively. In detail, the marks 142A, 142B, and 142C are marked at positions on the main surface 141A where the footing widths are 410 mm, 520 mm, and 600 mm, respectively.

As shown in FIG. 5, the portion of each footing formwork 140 with the mark 143 is overlapped with either the protrusion 112L or the protrusion 112R of the base 110 and fixed with a nail 150, as will be explained in the construction method described later.

Also, as shown in FIG. 5(A), if the width of the footing is set to 410 mm to obtain a footing ground pressure that corresponds to the bearing capacity of the ground, the part of the footing formwork 140 with the mark 142A is overlapped with the through hole 121A of either the guide member 120L or the guide member 120R extending from the base 110, and then fixed to the ground work with the nail 150.

In addition, if the width of the footing is set to 520 mm (see FIG. 5(B)) or 600 mm (see FIG. 5(C)) to obtain the desired ground pressure, the parts of the footing formwork 140 with marks 142B and 142C are overlapped with the through holes 121B and 121C of the guide member 120L or the guide member 120R, respectively, and fixed to the ground with nails 150.

Here, in order to obtain the desired ground pressure, the width of the bottom end surface of the footing that comes into contact with the top end of the foundation 200 is important. In other words, the part of the footing other than the bottom end surface is not important in terms of obtaining the desired ground pressure. If the footing formwork 140 bulges too much upward between the protrusion 112L of the base 110 and the guide member 120L, fresh concrete will be wasted. Therefore, it is preferable that the footing formwork 140 is close to a straight line, as shown by the virtual line V in Figure 5, when viewed in a plane from the extension direction X, between the protrusion 112L of the base 110 and the guide member 120L. The position of each mark 142 on the footing formwork 140 is determined from this perspective.

The minor angle between the footing formwork 140 and the top edge of the foundation work 200 may be set at approximately 45 degrees. To satisfy this regulation, the height of the base 110 is changed. However, the minor angle between the footing formwork 140 and the top edge of the foundation work 200 is not limited to 45 degrees and may be another angle.

[Assembly of formwork 100 (construction method)]
The construction method includes a base installation step, a footing formwork installation step, and a riser formwork installation step. The footing formwork installation step includes a first fixing step and a second fixing step.

The worker carries out the base installation process. In the base installation process, as shown in FIG. 4, multiple bases 110 are placed on the ground work top end 200 with a gap in the extension direction X. In detail, in each base 110, the end face 111B is in direct contact with the ground work top end 200, the end face 111T faces upward, and the side faces 111L and 111R face left and right, respectively. The gap is slightly shorter than the length of the footing formwork 140. Hereinafter, two bases 110 adjacent to each other in the extension direction X on the ground work top end 200 are also referred to as adjacent bases 110.

In addition, due to the base installation process, the guide members 120L, 120R extend from the lower left and right corners of each base 110 to the left and right (i.e., both sides) along the ground work top edge 200. As a result, in the guide members 120L, 120R, the through holes 121A, 121B, 121C (see Figures 1 and 2) are lined up in the width direction Y in this order when viewed from the base 110. Each of the through holes 121A to 121C indicates a fixing position for fixing the footing formwork 140 to the ground work top edge 200 with a nail 150. Here, the distance between the through holes 121A of the guide members 120L, 120R is approximately 410 mm. The distance between the through holes 121B is approximately 520 mm, and the distance between the through holes 121C is approximately 600 mm.

Then, the worker performs reinforcing bar arrangement by assembling reinforcing bars on each base 110. Note that the reinforcing bars are not shown in Figure 4.

The worker performs the first fixing process. In the first fixing process, the footing formwork 140 is aligned with the adjacent base 110, and then the footing formwork 140 is fixed to the adjacent base 110. In detail, both ends of the mark 143 are aligned on each of the protrusions 112L of the adjacent base 110. Then, the footing formwork 140 and each of the protrusions 112L are punched out with nails 150 from the position of the mark 143 on each of the protrusions 112L of the footing formwork 140. Using the same procedure, another footing formwork 140 is fixed to each of the protrusions 112R of the adjacent base 110 with nails 150.

The worker performs the second fixing process. In the second fixing process, the two footing formworks 140 and the guide members 120L and 120R are aligned, and then the two footing formworks 140 are fixed to the guide members 120L and 120R. In detail, the worker selects one of the three marks 142 marked on each footing formwork 140 based on the load of the entire house to be built and the bearing capacity of the foundation. Next, in one footing formwork 140, both ends of the selected mark 142 are aligned on the corresponding through holes 121 in each guide member 120L of the adjacent base 110. Then, in the footing formwork 140, the footing formwork 140 is punched out with a nail 150 from the position of the selected mark 142 on each guide member 120L. As a result, the footing formwork 140 is fixed to the foundation via the guide member 120L. Using a similar procedure, another footing formwork 140 is fixed to each guide member 120R of the adjacent base 110 with nails 150.

In the mounting process of the footing formwork, the upper end of the footing formwork 140 is fixed to one of the protruding pieces 112L, 112R of the adjacent base 110. The lower end of the footing formwork 140 is fixed to one of the guide members 120L, 120R. In detail, as shown in FIG. 5(A), when the width of the footing is 410 mm, the lower end of the footing formwork 140 is fixed using the mark 142A and the through hole 121A. As shown in FIG. 5(B), when the width of the footing is 520 mm, the lower end of the footing formwork 140 is fixed using the mark 142B and the through hole 121B. As shown in FIG. 5(C), when the width of the footing is 600 mm, the lower end of the footing formwork 140 is fixed using the mark 142C and the through hole 121C. As a result, the footing formwork 140 is generally linear when viewed in a plan view from the extension direction X between the protrusion 112L and the guide member 120L, but is curved and bulges slightly diagonally upward.

The order of the first and second fixing steps may be reversed.

After the footing formwork installation process, the worker performs the rising formwork installation process. In detail, in the rising formwork installation process, the two rising formworks 130 are placed on the end faces 111T of the adjacent bases 110 as shown in FIG. 4, and are spanned between them so as to face each other with a gap in the width direction Y. At this time, each rising formwork 130 is placed on the upper end of the footing formwork 140. As a result, the upper end of the footing formwork 140 is clamped between the rising formwork and the end face 111T of the adjacent base 110. The position of each rising formwork 130 relative to each base 110 is determined by a jig such as a width stopper (not shown).

This concludes the explanation of the construction method for the formwork 100. After assembling the formwork 100, the footing formwork 140 is backfilled, and then the ready-mix concrete is poured.

[Function and effect of formwork 100]
According to the formwork 100, the footing formwork 140 is not bulky because it has a flat plate shape before the formwork 100 is assembled. In other words, the footing formwork 140 is easy to transport.

The width of the footing can be changed by the through holes 121 used to fix the footing formwork 140. When a worker fixes the footing formwork 140 to the top edge of the foundation 200 with nails 150, if the guide member 120 is not present, it is difficult for the worker to know where to drive the nails 150. As a result, the width of the footing may vary. However, with the formwork 100 according to the embodiment, the base 110 has the guide member 120, so that the worker can easily know where to drive the nails 150. As a result, the width of the footing is less likely to vary.

Furthermore, the footing formwork 140 bulges upward after the footing formwork installation process (see FIG. 5). This shape allows the formwork 100 to have strength after assembly. In detail, the footing formwork 140 bulges upward after the formwork 100 is assembled and before the ready-mix concrete is poured, allowing it to withstand the load from above of soil and the like caused by backfilling.

In addition, each guide member 120 has a plurality of through holes 121 formed at a plurality of predetermined locations. Each footing formwork 140 has a plurality of marks 142 at a plurality of predetermined locations. This makes it easier for the worker to understand where to drive the nails 150 into the footing formwork 140 to obtain the desired footing width, and allows the dimensions of the completed footing to be appropriate (see FIG. 5). This makes it possible to reduce waste of ready-mix concrete and to make the area of the bottom end of the footing appropriate. Also, footings of various shapes can be constructed with a single footing formwork 140.

In addition, after the formwork 100 is assembled, the upper end of the footing formwork 140 is clamped between the rising formwork and the end surface 111T of the adjacent base 110. The footing formwork 140 is unlikely to separate from the base 110. This prevents the fresh concrete from leaking out of the upper end of the footing formwork 140 due to the pressure of the fresh concrete when it is poured.

The footing formwork 140 is made of iron and is buried in the ground together with the slab. Even if the footing formwork 140 remains buried, it will eventually turn into iron sand. In other words, the footing formwork 140 does not place a burden on the environment. Although the base 110 is made of resin, it remains in the slab, so there is no need to consider the environmental burden.

[Modification]
In the embodiment, the upper end of the footing formwork 140 is fixed to the base 110. However, this is not limited thereto, and the upper end of the footing formwork 140 may be fixed to the rising formwork 130.

In the embodiment, the guide members 120L and 120R are integral with the base 110. However, this is not limited thereto, and the guide members 120L and 120R may be separate from the base 110.

In the embodiment, the number of each of the marks 142 and the through holes 121 is three. However, the number of each of the marks 142 and the through holes 121 may be at least one. Furthermore, the positions of these are not limited to 410 mm, 520 mm, and 600 mm, and may be appropriately determined as necessary.

Reference Signs List 100: Formwork for slab footing 110: Base 120: Guide member 121: Multiple through holes 121A to 121C: Through holes 130: Rising formwork 140: Footing formwork 142: Multiple marks 142A to 142C: Marks 143: Mark

Claims (5)

With the base,
A rising formwork supported by the base;
A bendable flat-plate-shaped footing formwork;
A formwork for a slab foundation comprising guide members each extending from the base to both sides,
The guide member has a plurality of through holes for fixing the lower end of the footing formwork aligned along the extension direction,
A plurality of marks indicating a plurality of fixing positions corresponding to a plurality of through holes of the guide member are provided on a lower end portion of the footing formwork,
The footing formwork has an upper end which is fixed to the base or the rise formwork, and a lower end which is fixed to the guide member from one of the multiple fixing positions by a nail which passes through one of the multiple through holes which corresponds to the fixing position , thereby forming a curved formwork for a slab footing which bulges upward. The formwork for a slab foundation according to claim 1 , wherein an upper end of the footing formwork is located between the base and the riser formwork. 3. The formwork for a strip footing according to claim 1 or 2 , wherein the footing formwork is made of iron and is buried in the ground together with the strip footing. A base is placed on the foundation and guide members are extended from the base to both sides.
While curving a flat footing form so as to bulge upward, an upper end of the footing form is fixed to the base, and a lower end of the footing form is fixed to the guide member by nailing the lower end of the footing form from one of the fixing positions indicated by a plurality of marks on the lower end to a through hole corresponding to the fixing position among a plurality of through holes arranged in the extension direction of the guide member,
A method for constructing formwork for a slab foundation in which a rising formwork is placed on the base. 5. The method for constructing a form for a slab foundation according to claim 4 , wherein an upper end of the footing form is sandwiched between the base and the rising form.

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