JP6999170B2 - Formwork for pit construction and pit construction method - Google Patents

Description

The present invention relates to a pit-building formwork and a pit-building method in which a formwork body installed in an excavation hole is buried after the concrete is placed and hardened.

At a vehicle maintenance shop, tests are conducted to inspect lift devices that raise the vehicle from the floor, weight scales that measure the weight of the vehicle, brakes, speedometers, etc. in order to maintain and repair the bottom part of the vehicle. Various equipment such as machines will be installed in the pit dug down from the floor.
When installing these devices, a frame for securing space for the pit is formed from concrete in the excavation hole dug down from the floor, and concrete is placed between the frame and the peripheral wall of the excavation hole to form the pit. Form.
As a technique related to the construction of such a pit, although a refueling device is installed, the one described in Patent Document 1 is known.

In the refueling device described in Patent Document 1, a steel pit as a fall prevention member to be buried in the island is fastened to the bed with anchor bolts so that the upper end of the steel pit by the steel rectangular frame is exposed. By fastening the bed and the housing body with bolts, the housing body is installed on the island via the bed.

In the refueling device described in Patent Document 1, a steel pit made of a rectangular steel frame is used as a formwork to form a pit in the island, and the steel pit is buried as it is after the concrete is hardened, and the upper end thereof is filled. It is stated that it will be buried in the island so that it will be exposed.

Japanese Patent No. 3975678

Here, a conventional pit construction method in which equipment is installed in the pit will be described with reference to the drawings.
As shown in FIG. 5 (A), a reinforcing bar R is arranged on the bottom surface D1 of the excavation hole D, concrete is poured, and as shown in FIG. 5 (B), a bottom plate P1 is formed to form a flat surface. Form.
Next, as shown in FIG. 5C, a peripheral wall formwork F for forming a peripheral wall of the pit is formed on the batholith P1 with a wooden plate or the like, and concrete is poured into the peripheral wall formwork F. do. At this time, an L-shaped metal fitting A called an angle is installed at the edge of the peripheral wall formwork F which is a pit.
Then, as shown in FIG. 5 (D), by placing concrete between the peripheral wall D2 of the excavation hole D and the peripheral wall formwork F, a pit P in which the concrete is surrounded and the equipment is installed is formed. The concrete.

However, this conventional pit construction method requires two concrete placements. In the example shown in FIG. 5, when the concrete for the batholith P1 in the figure (B) is placed, the casting formwork F in the figure (C) cannot be installed without waiting for the hardening. It takes time.

Therefore, an object of the present invention is to provide a pit construction formwork and a pit construction method capable of shortening the construction period.

The formwork for pit construction of the present invention is installed in an excavation hole on the floor surface, and the formwork body formed by the frame member surrounding the pit in which the equipment is installed is buried after the cast concrete is hardened. The formwork body is provided with a height positioning member for opening a gap between the formwork body and the bottom surface of the excavation hole.

The pit construction method of the present invention is for pit construction in which a formwork body formed by a frame member that is installed in a drilling hole on a floor surface and surrounds a pit in which equipment is installed is buried after the placed concrete is hardened. In the method using a formwork, a step of arranging the pit construction formwork provided with a height positioning member below the formwork body in a drilling hole, and the formwork body and the above. A step of placing concrete up to the floor surface between the peripheral wall of the drilling hole and a step of placing concrete having a thickness to be the bottom of the drilling hole inside the formwork body.
It is characterized by including a step of hardening the concrete.

According to the present invention, since the formwork body is provided with a height positioning member for opening a gap between the formwork body and the bottom surface of the excavation hole, the formwork body is installed in the excavation hole and concrete. Since a layer with the thickness of the bottom plate is formed under the formwork body just by placing the bottom plate, the bottom plate can be formed when it is hardened. Further, by placing concrete on the outside of the formwork body, a floor surface can be formed around the formwork body. Therefore, the concrete casting can be completed in one casting process.

The height positioning member can be a foot portion provided at the lower end of the formwork body. By positioning the formwork body from the bottom of the excavation hole with the foot, the thickness of the bottom of the pit can be easily adjusted.

The height positioning member can be connected to the upper end of the formwork body to form a hanging portion for suspending the formwork body in the excavation hole. By simply suspending the formwork body from the excavation hole, the height of the formwork body can be positioned regardless of the state of the bottom surface of the excavation hole.

If an outward flange portion is formed on either one or both of the upper end and the lower end of the formwork body, concrete enters between the flange portions and is firmly held, so that the formwork body is held firmly. Can be firmly fixed to concrete. Further, if the flange portion is formed at the upper end of the form body, the opening edge portion of the pit can be reinforced.

If a reinforcing portion for connecting the flange portions is formed with a gap between the outer wall of the formwork body and the outer wall of the formwork body, the frame member of the formwork body is prevented from bending or twisting, and the concrete is flanged. Since concrete enters between the outer wall and the reinforcing portion when entering between the portions, the formwork body can be further firmly fixed to the concrete.

The flange portion is formed at the outward portion and the tip of the outward portion, and is a downward portion facing downward at the upper end of the formwork body and an upward facing portion at the lower end of the formwork body. Can be provided.
When the concrete is placed, the concrete enters the inside of the flange portion so as to be embraced, so that the flange portion can be more firmly fixed to the concrete.

According to the present invention, since concrete is placed on the outside of the formwork body, a floor surface can be formed around the formwork body, so that the concrete can be placed in one casting process. Can be completed. Therefore, the construction period can be shortened.

It is a perspective view which shows the formwork for pit construction which concerns on Embodiment 1 of this invention. (A) to (D) are diagrams for explaining each process of the pit construction method using the pit construction form shown in FIG. 1. It is a figure for demonstrating the modification of the formwork for pit construction which concerns on Embodiment 1 of this invention, and is sectional drawing of the frame member of the formwork body. It is a figure which shows the formwork for pit construction which concerns on Embodiment 2 of this invention. (A) to (E) are diagrams for explaining each process of the conventional pit construction method.

(Embodiment 1)
The pit construction formwork according to the first embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the pit construction formwork 10 is a formwork for constructing a pit that is installed in an excavation hole on a floor surface, is buried after the cast concrete is hardened, and equipment is installed. The pit construction formwork 10 has a steel formwork body 20 formed of a plate-shaped member surrounding the pit in which the equipment is installed.

In the first embodiment, the formwork body 20 is formed in a rectangular shape in a plan view. In the formwork body 20, frame members 20p formed of plate-shaped members corresponding to each side are connected to each other by nuts and bolts.
The vertical length of the frame member 20p is such that when the adjuster bolt described later is erected in the excavation hole, the upper end 20t of the form body 20 is at the same position as the floor surface where the excavation hole is opened. It is formed.

An outward flange portion 22 is formed at the upper end 20t of the form main body 20 (frame member 20p). Further, an outward flange portion 23 is also formed on the lower end 20b of the formwork main body 20.
Between the flange portion 22 and the flange portion 23, a reinforcing portion 24 made of a rectangular plate material connects both ends to the flange portion 22 and the flange portion 23, and leaves a gap between the flange portion 22 and the outer wall 21 of the formwork body 20. It is formed in a state of being.
The brace portion 25 is connected to both adjacent frame members 20p of the form body 20 by bolts and nuts. Therefore, the brace portion 25 can be removed by removing the inner nut screwed into the bolt from the bolt through which the frame member 20p and the brace portion 25 are inserted from the outside.

An adjuster bolt 30 that serves as a foot portion that functions as a height positioning member is provided at the lower end 20b of the formwork body 20. The adjuster bolt 30 has a length that positions the formwork body 20 at a height equal to or higher than the thickness of the batholith.

A pit construction method using the pit construction formwork according to the first embodiment of the present invention configured as described above will be described with reference to the drawings.
First, the worker mounts the frame member 20p of the formwork body 20 in a disassembled state on the vehicle and transports it to the installation location. Then, the worker assembles the formwork body 20 by connecting the frame member 20p with nuts and bolts at the installation location. Since the formwork body 20 can be disassembled, it is easy to transport.
Next, as shown in FIG. 2A, in the reinforcing bar arrangement step, reinforcing bars R for reinforcing the bottom plate and the peripheral portion of the pit are arranged on the bottom surface D1 of the excavation hole D dug down from the floor surface.

Next, as shown in FIG. 2B, the pit construction formwork 10 shown in FIG. 1 is arranged in the excavation hole D in the installation process. At this time, the adjuster bolt 30 is adjusted so that the position of the lower end 20b of the formwork body 20 is the height position of the surface plate.

Next, in the placing step, concrete is placed on the outer side 20o of the formwork body 20 (between the outer wall 21 and the peripheral wall D2 of the excavation hole D). The formwork body 20 has a downward gap due to the adjuster bolt 30. Therefore, concrete can be poured from the outer side 20o of the formwork body 20 to the inner side 20i by passing under the formwork body 20.
Further, when the concrete on the inner side 20i is insufficient due to the pouring from the outer side 20o of the formwork main body 20, concrete may be directly poured into the frame from above the formwork main body 20 and the concrete may be poured on the inner side 20i.
The concrete inside the formwork body 20 is up to the thickness of the lower end 20b of the formwork body 20. The concrete on the outer side 20o has a height up to the opening of the excavation hole D.

As a result, the concrete is cast to the thickness of the lower end 20b on the inner side 20i and higher than that on the outer side 20o. However, the viscosity of concrete is high, and the depth of the excavation hole D is such that the equipment is installed. Therefore, even if the pressure due to the thickness of the concrete is applied from the outer side 20o to the inner side 20i through the lower part, the concrete placed on the outer side 20o does not wrap around the lower part of the formwork main body 20 and flow into the inner side 20i, and the inner side 20i The height of concrete does not rise.

Therefore, as shown in FIG. 2C, concrete is poured to the thickness of the lower end 20b of the pit construction formwork 10, so that a layer having the thickness of the batholith P1 is formed below the formwork body 20. When cured, the batholith P1 can be formed. Further, as shown in FIG. 2D, concrete is cast on the outer side 20o of the formwork body 20, so that a floor surface FL can be formed around the formwork body 20.

Next, the nut connecting the brace portion 25 shown in FIG. 1 to the frame member 20p is removed, and the brace portion 25 is removed. After that, once the concrete is hardened, the equipment can be installed by the equipment installation worker in the pit P (see FIG. 2D) surrounded by the pit construction formwork 10, so that the pit construction formwork 10 can be installed. The worker who installs the formwork can finish the work without waiting for the concrete to harden.

As described above, according to the pit construction method using the pit construction formwork according to the first embodiment, the pit P can be constructed in one concrete placing step, so that the construction period can be shortened.

As shown in FIGS. 2B and 2C, the thickness of the bottom plate P1 of the pit P can be easily adjusted by positioning the formwork body 20 from the bottom surface D1 of the excavation hole D by the adjuster bolt 30. Can be done.
Since the outward flange portion 22 is formed at the upper end 20t of the formwork main body 20 shown in FIG. 1, it is possible to omit the installation of the L-shaped metal fitting that reinforces the peripheral edge portion of the pit P.

Further, since the flange portions 22 and 23 are formed on the upper end 20t and the lower end 20b of the formwork main body 20, concrete enters between the flange portions 22 and 23 and is firmly held, so that the formwork main body is held firmly. 20 can be firmly fixed to concrete.

Since the reinforcing portion 24 is formed between the flange portions 22 and 23, bending and twisting of the frame member 20p of the formwork body 20 alone is suppressed, and when concrete enters between the flange portions 22 and 23. Since concrete enters between the outer wall 21 and the reinforcing portion 24, the formwork body 20 can be further firmly fixed to the concrete.

Since the brace portion 25 is connected to the frame member 20p, deformation of the formwork body 20 until the concrete is hardened can be suppressed, and it can be easily removed after the concrete is hardened, providing a space for installing the equipment. Can be secured.

In the first embodiment, the adjuster bolt 30 is provided as a foot portion serving as a height positioning member, but as shown in FIG. 2B, between the formwork main body 20 and the bottom surface D1 of the excavation hole D. As long as a gap can be left in the space and the bottom plate P1 shown in FIG. 2C can be formed, a simple rod-shaped member may be used.

(Modified Example of Embodiment 1)
The pit construction formwork according to the modified example of the first embodiment of the present invention will be described with reference to the drawings. In FIG. 3, the same components as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.
The pit construction formwork 11 shown in FIG. 3 is a cross-sectional view of a frame member 20q of the formwork body.
In the formwork body 20x, outward flange portions 221,231 are formed at the upper end 20t and the lower end 20b.

The flange portion 221 formed at the upper end 20t of the formwork body 20x is formed of an outward facing portion 221a and a downward facing portion 221b formed at the tip of the outward facing portion 221a.
The flange portion 231 formed at the lower end 20b of the formwork body 20x is formed of an outward facing portion 231a and an upward facing portion 231b formed at the tip of the outward facing portion 231a.

In this way, the flange portions 221 and 231 are formed not only with the outward portions 221a and 231a but also with the downward portions 221b and / and the upward portions 231b. Since it is embraced inside the concrete, the flange portions 221,231 can be more firmly fixed to the concrete.

In the present embodiment, the flange portions 221,231 are formed on both the upper end 20t and the lower end 20b of the formwork main body 20x, but either one may be used. In that case, the flange portion 221 or the flange portion 231 may be omitted, or the flange portions 22 and 23 shown in FIG. 1 may be used.
However, in order to reinforce the opening edge portion of the pit P (see FIG. 5), it is desirable that the flange portions 22 and 221 are formed at least at the upper end 20t.

(Embodiment 2)
The pit construction formwork according to the second embodiment of the present invention will be described with reference to the drawings.
In FIG. 4, the same components as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.
In the formwork 12 for pit construction shown in FIG. 4, the formwork body 20 is provided with a height positioning member for opening a gap between the formwork body 20 and the bottom surface D1 of the excavation hole D.
In the second embodiment, the height positioning member is connected to the upper end of the formwork body 20 to form a hanging portion 40 for suspending the formwork body 20 in the excavation hole D.

The hanging portion 40 includes a rod-shaped member 41 suspended from peripheral portions D2 on both sides of the excavation hole D.
The rod-shaped member 41 is fixed to the formwork body 20 by screwing a bolt 42b in a state where the rod-shaped member 41 is inserted into a nut 42a attached to the lower surface of the flange portion 22.
Further, the rod-shaped member 41 is fixed to the peripheral portion D2 by screwing bolts 43b in a state where the rod-shaped member 41 is inserted into the concrete anchors 43a driven into the peripheral portions D2 on both sides of the excavation hole D.

At this time, if the peripheral portion of the excavation hole D is uneven, the rod-shaped member 41 is in an inclined state. In that case, the thin plate 44 is inserted as a spacer under the rod-shaped member 41, or the height of the bolt 43b is adjusted so that the rod-shaped member 41 is horizontal.

The formwork body 20 suspended by the suspension portion 40 has a gap of the thickness of the batholith below the excavation hole D.
Therefore, by placing concrete in such a state, the bottom board and the floor surface around the peripheral portion of the formwork main body 20 can be formed at the same time.
The rod-shaped member 41 can be removed by placing the concrete and removing the bolts 42b and 43b after the concrete has hardened.

In this way, the formwork body 20 is suspended in the excavation hole D1 by connecting the height positioning member to the upper end of the formwork body 20 to form a hanging portion 40 for suspending the formwork body 20 in the excavation hole D. By simply lowering it, the height of the formwork body can be positioned regardless of the state of the bottom surface D1 of the excavation hole D.

The pit construction formwork according to the first and second embodiments of the present invention has been described above.
Although the pit construction formwork 10 shown in FIG. 1 is formed in a rectangular shape in a plan view, the formwork body can be deformed according to the pit shape.

The present invention is suitable for constructing a pit formed in a drilling hole dug down from a floor surface and in which equipment is installed.

10,11,12 Formwork for pit construction 20,20x Formwork body 20t Upper end 20b Lower end 20i Inner 20o Outer 20p, 20q Frame member 21 Outer wall 22,23,221,231 Flange part 221a, 231a Outward part 221b Downward part 231b Upward part 24 Reinforcement part 25 Brace part 30 Adjuster bolt 40 Suspension part 41 Rod-shaped member 42a Nut 42b Bolt 43a Concrete anchor 43b Bolt 44 Thin plate D Drilling hole D1 Bottom D2 Peripheral wall R Reinforcing bar P Pit P1 Bottom

Claims (7)

In the formwork for pit construction, the formwork body formed by the frame member that is installed in the excavation hole on the floor and surrounds the pit where the equipment is installed is buried after the cast concrete is hardened.
A pit construction formwork provided with a height positioning member in the formwork body for allowing a gap between the formwork body and the bottom surface of the excavation hole. The pit construction formwork according to claim 1, wherein the height positioning member is a foot portion provided at the lower end of the formwork body. The pit construction formwork according to claim 1, wherein the height positioning member is a hanging portion that is connected to the upper end of the formwork body and suspends the formwork body in the excavation hole. The pit-building formwork according to any one of claims 1 to 3, wherein an outward flange portion is formed on one or both of the upper end and the lower end of the form body. The pit construction formwork according to claim 4, wherein a reinforcing portion for connecting the flange portions is formed with a gap between the formwork and the outer wall of the formwork body. The flange portion is formed at the outward portion and the tip of the outward portion, and is a downward portion facing downward at the upper end of the formwork body and an upward facing portion at the lower end of the formwork body. The pit construction formwork according to claim 4 or 5. A pit construction method using a pit construction formwork in which the formwork body formed by the frame member that is installed in the excavation hole on the floor and surrounds the pit where the equipment is installed is buried after the cast concrete is hardened. In
The pit construction formwork, which is a gap below the formwork body and is provided with a height positioning member for opening a gap between the formwork body and the bottom surface of the excavation hole, is arranged in the excavation hole. And the process to do
A concrete having a height up to the floor is placed between the formwork body and the peripheral wall of the excavation hole, and concrete having a thickness that serves as the bottom of the excavation hole is placed inside the formwork body. And the process to do
A pit construction method including a step of hardening the concrete.

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