JP7774018B2 - Concrete structure construction method - Google Patents

Description

This disclosure relates to a formwork unit that does not require removal and allows concrete to be poured without using formwork supports, and a concrete structure construction method that uses the formwork unit.

During the construction process of concrete structures by pouring concrete, formwork for defining the area to be filled with concrete raw materials is often formed by assembling multiple panels (hereinafter sometimes referred to as "removable panels") that can be removed from the concrete structure after construction. Technology related to such formwork for pouring concrete is described, for example, in the following Patent Documents 1 to 3.

Japanese Patent Application Publication No. 7-279410 Japanese Patent Application Laid-Open No. 2004-183466 JP 2012-224990 A

For example, if the concrete structure to be formed has a stepped structure, the removable panels that define the side wall surfaces of the stepped structure must be removed after the concrete structure is constructed. Therefore, traditionally, the removable panels are assembled with their bottom ends raised above the floor surface (i.e., the removable panels are assembled with a specified gap between their bottom ends and the floor surface).

However, when concrete is poured with the removable panel installed in this manner, partial leakage of unhardened concrete, i.e., overflow, occurs from the gap between the removable panel and the floor surface. As this overflowing concrete hardens, an excess slope is formed compared to the intended inside corner shape. In order to form the appropriate inside corner shape, work must be carried out to remove the excess (chipping work). Repair work may also be required for the areas that have been removed. The need for such work undesirably increases the work, time, and cost required to construct a concrete structure with a stepped section.

Furthermore, in order to streamline panel removal work after the construction of a concrete structure, the assembly of removable panels may be simplified. In such cases, the removable panels are prone to distortion due to the weight and load (e.g., impact load) of the concrete raw materials filled and flowing within the compartment defined by the formwork. If the assembled removable panels become distorted, the resulting concrete structure will also become distorted. Concrete structures with such distortion need to be repaired, and the need for such repairs undesirably increases the work, time, and cost required for constructing the concrete structure.

In addition, the removed panels needed to be cleaned before they could be reused, which was time-consuming and generated a large amount of wastewater. Furthermore, panels that could not be reused even after cleaning were discarded, resulting in the problem of large amounts of industrial waste being generated after the concrete structure was constructed.

On the other hand, when constructing a concrete structure without using the above-mentioned removable panels, it is common to apply mortar with a trowel or other tool. When applying mortar with a trowel or other tool to a surface other than the upward-facing surface, applying a thick layer of mortar at once is prone to peeling. Therefore, a method is adopted in which the mortar is applied thinly and then applied again after it has hardened to a certain extent to reach the desired thickness. However, this method is undesirable because it increases the work, time, and cost required for constructing a concrete structure. Furthermore, even after the mortar has hardened, it is prone to peeling, particularly on the side walls of walls, ceilings, and downward-facing surfaces such as the bottoms of beams, which can collapse in an earthquake or other event.

The present disclosure has been devised under these circumstances, and its purpose is to provide a form unit that does not need to be removed, for pouring concrete without using formwork supports.
Another object of the present disclosure is to provide a non-removable prefabricated formwork unit for concrete pouring without the use of formwork shoring.
Another object of the present disclosure is to provide a method for constructing a concrete structure using the prefabricated formwork unit.
Another object of the present disclosure is to provide a renovation method for renovating a concrete structure using the prefabricated formwork unit.

To solve the above problem, the present disclosure provides a formwork unit for pouring concrete without using formwork shoring,
The apparatus includes an embedded panel, a connecting member, a first fastener, a flange, and a second fastener,
The connecting member has a separator portion and a male thread portion provided at one end of the separator portion,
the second fastener has a head and a male thread;
the embedded panel has a hole through which the male thread portion of the second fastener can pass;
The flange has a hole through which the male thread of the second fastener can pass and an end surface for contacting the surface of the embedded panel,
the first fastener is a convex member having an end surface for contacting the rear surface of the embedded panel, and a shaft portion of the convex member has an internal thread portion that threadably engages with the external thread portion of the connecting member and the external thread portion of the second fastener;
The sum of the contact area of the flange with the surface of the buried panel and the contact area of the first fixing device with the back surface of the buried panel is 2% or more of one surface area of the buried panel.
To provide a formwork unit for pouring concrete.

The present disclosure also provides a method for fixing a panel to a surface of the buried panel, the method comprising: a) providing a fastener for fastening a panel to a surface of the buried panel; b) providing a fastener for fastening a panel to a surface of the buried panel; c) providing a fastener for fastening a panel to a surface of the buried panel;
To provide the form unit, which is a form unit for forming a form for pouring concrete by assembling a plurality of embedded panels in a line in the height direction so that they are flush with each other.

The present disclosure also provides the formwork unit, which includes a flanged second fastener having a flange-shaped head and a male threaded portion, instead of the flange and second fastener.

The present disclosure also provides the formwork unit, in which the embedded panel has a longitudinal dimension of 2000 mm or less, a transverse dimension of 1000 mm or less, and a thickness of 15 mm or less.

The present disclosure also provides a method for manufacturing a buried panel having a thickness of 15 mm or less,
The form unit is a form unit in which a plurality of embedded panels are aligned and assembled in a flush manner in the height direction to form a form for pouring concrete.

The present disclosure also provides a formwork unit as described above, in which the surface of the embedded panel that is installed facing the inside of the concrete-filled section includes an adhesion-improving surface.

The present disclosure also provides a formwork unit as described above, further comprising a connector for connecting two adjacent embedded panels flush with each other.

The present disclosure also provides a formwork unit as described above, further comprising a connector for connecting two adjacent embedded panels in a perpendicular manner to each other.

The present disclosure also provides the formwork unit, further comprising a height adjustment device for adjusting the height position of the embedded panel.

The present disclosure also provides a formwork unit for pouring concrete structures having a step structure of 1 m or less.

The present disclosure also provides a prefabricated formwork unit for forming a formwork for pouring concrete without using formwork shoring,
The apparatus includes an embedded panel, a connecting member, a first fastener, a flange, and a second fastener,
The connecting member has a separator portion and a male thread portion provided at one end of the separator portion,
the second fastener has a head and a male thread;
the embedded panel has a hole through which the male thread portion of the second fastener can pass;
The flange has a hole through which the male thread of the second fastener can pass and an end surface for contacting the surface of the embedded panel,
the first fastener is a convex member having an end surface for contacting the rear surface of the embedded panel, and a shaft portion of the convex member has an internal thread portion that threadably engages with the external thread portion of the connecting member and the external thread portion of the second fastener;
The sum of the contact area of the flange with the surface of the buried panel and the contact area of the first fixing device with the back surface of the buried panel is 2% or more of one surface area of the buried panel,
The assembled formwork unit is provided in such a manner that the male thread part of the second fixing tool is inserted into the hole of the buried panel from the surface side of the buried panel with a flange sandwiched therebetween, and the male thread part of the second fixing tool protruding to the back side of the buried panel and the male thread part of the connecting member are screwed together with the female thread part of the first fixing tool whose end face is abutted against the back side of the buried panel.

The present disclosure also provides a method for constructing a concrete structure by pouring concrete using the prefabricated formwork unit, comprising:
Step 1: arranging prefabricated formwork units so that the front side of the embedded panel of the prefabricated formwork units forms at least one surface of a concrete structure, thereby defining a compartment to be filled with concrete raw materials;
a step 2 of fixing the prefabricated formwork unit by connecting an end of the separator portion of the placed prefabricated formwork unit to a non-movable portion located inside the concrete filling section to form a formwork;
and (3) supplying concrete raw materials into the formed formwork.

The present disclosure also provides a concrete structure construction method in which the concrete structure is a concrete structure having a step structure of 1 m or less.

The present disclosure also provides the concrete structure construction method, wherein the concrete structure is at least one structure made of concrete selected from the group consisting of stairs, rising steps, thresholds, and beams.

The present disclosure also provides a method for renovating a concrete structure by pouring concrete using the prefabricated formwork unit, comprising:
A process 1' of fixing an end of the separator portion of the prefabricated formwork unit to a surface to be repaired of a concrete structure to form a formwork;
and supplying concrete raw materials into the formed formwork.

The present disclosure also provides a concrete structure in which the embedded panel included in the formwork unit forms at least one surface selected from the top, bottom, and side surfaces of the concrete structure.

The formwork unit disclosed herein reinforces the connection between the embedded panel and the connecting member with flanges and other components, making it possible to form a formwork that can withstand the weight of the concrete raw materials and loads (e.g., impact loads) without using formwork shoring. Furthermore, use of the formwork unit disclosed herein reduces the work, time, and cost required to construct a concrete structure, and allows for the formation of a strong, aesthetically pleasing concrete structure through simple and speedy operation.

Furthermore, by using the formwork unit of the present disclosure, it is possible to stop or reduce the use of panels that are removed after construction and become industrial waste. Therefore, by using the formwork unit of the present disclosure, it is also possible to reduce the environmental burden.

For example, when the concrete structure to be formed is a ceiling or the like, conventional construction methods have had problems such as peeling and collapse. However, the concrete structure obtained using the formwork units disclosed herein has embedded panels that make up at least part of its surface, which are firmly fixed to the steel frames that form the foundation and framework. This prevents parts of the concrete structure from peeling or collapsing, dramatically improving earthquake resistance.

By using the formwork unit disclosed herein to renovate a concrete structure, the surface of the concrete structure to be renovated can be renovated simply, quickly, and beautifully. Furthermore, the renovated concrete structure can also be endowed with excellent earthquake resistance.

1 is a perspective view showing an example of a form unit X of the present disclosure. FIG. 10A-10C illustrate variations of buried panels of the present disclosure. FIG. 10 is a perspective view showing another example of a form unit X of the present disclosure. FIG. 10 is a perspective view showing an example of a second fixing device of the present disclosure. 1A is a perspective view showing an example of a fixture 30 according to the present disclosure, and FIG. 1B is a cross-sectional view showing the example. 10 illustrates a variation of the buried panel of the present disclosure. 10 illustrates a variation of the buried panel of the present disclosure. FIG. 1 is a cross-sectional view showing an example of a prefabricated formwork unit according to the present disclosure. FIG. 10 is a cross-sectional view showing another example of the prefabricated formwork unit of the present disclosure. FIG. 10 is a cross-sectional view showing another example of the prefabricated formwork unit of the present disclosure. 1 is a schematic diagram showing an example of a method for assembling a prefabricated formwork unit in a concrete structure construction method according to the present disclosure. FIG. FIG. 10 is a schematic diagram (side view) showing another example of a method for assembling prefabricated formwork units in the concrete structure construction method of the present disclosure. FIG. 13 is a top view of an example of assembly of the prefabricated formwork unit shown in FIG. 12. FIG. 10 is a schematic diagram (side view) showing another example of a method for assembling prefabricated formwork units in the concrete structure construction method of the present disclosure. FIG. 10 is a schematic diagram showing another example of a method for assembling prefabricated formwork units in the concrete structure repair method of the present disclosure. 10A and 10B are diagrams illustrating a prefabricated formwork unit according to a second embodiment. 10A and 10B are diagrams illustrating a prefabricated formwork unit according to a second embodiment. 10A and 10B are diagrams illustrating a concrete structure constructed using the prefabricated formwork unit according to the second embodiment. FIG. 10 is a diagram showing a form unit according to a second embodiment. 10 is a schematic perspective view of the first embedded panel according to the second embodiment, viewed from the back side. FIG. A schematic oblique view of the second embedded panel of embodiment 2 viewed from the back side. A schematic oblique view of the third embedded panel of embodiment 2 viewed from the back side. FIG. 10 is a schematic perspective view of an auxiliary member according to a second embodiment. 10A to 10C are diagrams illustrating the procedure of a concrete pouring step according to a second embodiment.

[Formwork unit]
The formwork unit X of the present disclosure is a formwork unit for pouring concrete without using formwork supports,
The apparatus includes an embedded panel 10, a connecting member 20, a first fastener 30, a flange 23, and a second fastener 40,
The connecting member 20 has a separator portion 21 and a male thread portion 22 provided at one end of the separator portion 21,
The second fastener 40 has a head 41 and a male thread 42.
The embedded panel 10 has a hole 13 through which the male thread portion 42 of the second fastener 40 can pass,
The flange 23 has a hole 24 through which the male thread portion 42 of the second fastener 40 can pass and an end surface 23A for contacting the surface of the embedded panel 10,
The first fastener 30 is a convex member having an end surface 31 for abutting the rear surface of the embedded panel 10, and has an internal thread portion 33 on the shaft portion of the convex member that threadably engages with the external thread portion 22 of the connecting member 20 and the external thread portion 42 of the second fastener 40,
The sum of the contact area of the flange 23 with the surface of the embedded panel and the contact area of the first fastener 30 with the back surface of the embedded panel is 2% or more of one surface area of the embedded panel.

Formwork units X are assembled to form prefabricated formwork units Y.

Formwork unit X is suitable as a formwork unit for forming a formwork for pouring concrete structures with step structures of 1 m or less (including, for example, step structures for modular baths and water return step structures) without using formwork supports.

(Buried panel 10)
The embedded panel 10 is a sheathing (i.e., a formwork placed in a position that is in direct contact with the concrete) that shapes the concrete structure, and is a component that forms at least a part of the concrete structure without being removed after the concrete raw materials have hardened.

The buried panel 10 is a rectangular plate having a surface 11 and an opposite surface 12. Materials for the buried panel 10 include inorganic materials such as thermoplastic resin, thermosetting resin, metal, cement, and ceramics; wood, paper, and laminated or mixed materials thereof. Lightweight construction is particularly important for stepped structures less than 1 meter in height (e.g., stepped structures for modular baths and water-repellent stepped structures). Therefore, in addition to thermoplastic resin plates, thin fiber-reinforced cement plates, laminated wood and thermosetting resin plates such as plywood, and lightweight metal plates such as aluminum plates can be used. Biodegradable plastic plates can also be used, which are expected to reduce environmental impact when disposing of unnecessary buried panels 10 during the demolition or repair of concrete structures. In this embodiment, a flat fiber-reinforced cement plate is used.

The buried panel 10 has a longitudinal dimension of, for example, 300 to 2420 mm.
The dimension in the short side direction is, for example, 20 to 2420 mm. In particular, from the viewpoint of reducing the manufacturing costs and transportation costs of the buried panel 10 and facilitating the assembly work of the buried panel 10, the dimension in the long side direction is preferably 300 to 2000 mm, and the dimension in the short side direction is preferably 20 to 1000 mm (particularly, 50 to 600 mm).

In this specification, when the embedded panel 10 is assembled to form a formwork for pouring concrete, the surface that is installed facing the inside of the concrete filling section 80 is referred to as surface 11, and the surface that is installed facing the outside of the concrete filling section 80 is referred to as surface 12.

Examples of flat fiber-reinforced cement boards include slate boards, calcium silicate boards, and slag gypsum boards. Slate boards contain, for example, cement, fiber (excluding asbestos), and admixtures as primary raw materials. Calcium silicate boards contain, for example, calcareous raw materials, siliceous raw materials, fiber (excluding asbestos), and admixtures as primary raw materials. Slag gypsum boards contain, for example, slag, gypsum, fiber (excluding asbestos), and admixtures as primary raw materials. JIS A 5430 specifies standards for these fiber-reinforced cement boards. From the perspective of water resistance, slate boards and calcium silicate boards are preferred as fiber-reinforced cement boards. Commercially available slate boards include, for example, "Selflex" manufactured by A&A Material Co., Ltd. Commercially available calcium silicate boards include, for example, "Hilac M" manufactured by A&A Material Co., Ltd. An example of a commercially available slag gypsum board is "Tiger Board" manufactured by Yoshino Gypsum Co., Ltd.

The thickness of the buried panel 10 is, for example, 2 mm or more, preferably 3 mm or more, more preferably 4 mm or more, particularly preferably 5 mm or more, and most preferably 6 mm or more. This configuration is preferable from the perspective of ensuring the strength of the buried panel 10, and therefore is preferable for preventing damage and deflection of the buried panel 10 during transportation and assembly, and when pouring concrete. Furthermore, the thickness of the buried panel 10 is, for example, 15 mm or less, preferably 12 mm or less, more preferably 10 mm or less, even more preferably 9 mm or less, particularly preferably 8 mm or less, and most preferably 7 mm or less. This configuration is preferable from the perspective of reducing the weight of the buried panel 10, and therefore is preferable from the perspective of reducing manufacturing and transportation costs of the buried panel 10 and making it easier to assemble the buried panel 10.

When used in step structures less than 1m in height (such as step structures for modular baths or water return step structures), it is preferable that the embedded panels are thin, as they are lightweight and easy to transport.

When a fiber-reinforced cement board is used as the embedded panel 10 and is used in a stepped structure with a height of 1 m or less (such as a stepped structure for a modular bath or a stepped structure for water return), the thickness of the embedded panel 10 is preferably 3 mm to 10 mm, and particularly preferably 5 mm to 8 mm.

The weight of the buried panel per ^m2 is, for example, 0.5 to 15 kg, and a range of 1 to 12 kg is preferable, and 2 to 11 kg is more preferable, as it provides both strength and lightness.

The buried panel 10 has a hole through which the male threaded portion 42 of the second fastener 40 passes, i.e., a through-hole 13 that passes between the surfaces 11 and 12 of the buried panel 10.

The number of through holes 13 that the buried panel 10 has is determined based on the size and shape of the buried panel 10, the stress acting on the buried panel 10 due to the weight of the concrete to be filled, and other factors, but is, for example, in the range of 1 to 20, preferably 1 to 10. The through holes 13 may be provided in a line, at the four corners, at the four corners and in the center, or in a zigzag pattern.

When a fiber reinforced cement board having a thickness of 3 mm to 10 mm is used for a stepped structure having a height of 1 m or less (for example, a stepped structure for a unit bath or a stepped structure for water return), the number of through holes 13 per 1 ^m2 of the installed embedded panel 10 is preferably 10 to 10.
The thinner the embedded panel 10, the more through holes can be used, reducing the work, time, and cost required for constructing a concrete structure, and allowing for a strong and aesthetically pleasing concrete structure to be formed through simple and speedy operation.

When a fiber-reinforced cement board having a thickness of 5 mm to 8 mm is used for constructing a unit bath step having a height of 200 mm, the number of through holes 13 per 1 ^m2 of the installed buried panel 10 is preferably 10 to 30, more preferably 14 to 25, and more preferably 16 to 22.

Furthermore, when a fiber-reinforced cement board having a thickness of 5 mm to 8 mm is used as the embedded panel 10 to construct a water-repellent step having a height of 60 mm, the number of through holes 13 per 1 ^m2 of the installed embedded panel 10 is preferably 30 to 50, and more preferably 36 to 46.

The embedded panel 10 may have a recess into which the flange 23 can be embedded so that the flange 23 is flush with the embedded panel 10 when the formwork unit X is assembled or when a concrete structure is constructed using the prefabricated formwork unit Y.

Surface 11 may be provided with an adhesion-improving surface over part or all of its surface. The adhesion-improving surface is, for example, a surface suitable for bonding with concrete, and is a surface that has been treated to improve adhesion to concrete. Providing an adhesion-improving surface can strengthen the bond with concrete and prevent the embedded panel 10 from peeling off from the concrete surface.

When used in a stepped structure with a height of 1m or less (such as a stepped structure for a modular bath or a water return stepped structure), after the poured concrete has hardened, the upper edge of the embedded panel 10 that extends above the concrete surface must be scraped and/or cut with a sander or similar tool to adjust the height to the concrete surface. Therefore, there is no need to provide an adhesive improvement surface in the upper area where the height of the embedded panel is adjusted.

The adhesion-improving surface of the buried panel 10 (e.g., a buried panel 10 that is a flat fiber-reinforced cement board) may be, for example, a hardened mortar layer surface, a textured surface, a mechanically roughened surface, or a combination of these. From the standpoint of mass production and economic efficiency of the buried panel 10, the hardened mortar layer surface is preferred as the adhesion-improving surface of the buried panel 10.

The surface of the hardened mortar layer on the embedded panel 10 can be formed by applying mortar to the area of the fiber-reinforced cement board where the adhesion-improving surface is to be formed, and then allowing it to harden. Examples of such mortar include polymer cement mortar, epoxy resin mortar, and cationic mortar.

Polymer cement mortar is, for example, a mortar that is a mixture of cement, fine aggregate, water, and a polymer dispersion or a re-emulsified powdered resin. Examples of polymer dispersions include ethylene vinyl acetate resin (EVA) and acrylic resin. Commercially available ethylene vinyl acetate resins that can be used as polymer dispersions include "Cellmighty 10" manufactured by Daicel FineChem Co., Ltd. and "HOUN Sealer N" manufactured by Houn Co., Ltd. Commercially available acrylic resins that can be used as polymer dispersions include "Super Petrock 400" manufactured by Asahi Kasei Corporation.

Cationic mortar is, for example, a mortar that is a mixture of cement, fine aggregate, water, and a cationic polymer dispersion or a cationic re-emulsifiable powdered resin. Examples of cationic polymer dispersions include cationic styrene-butadiene rubber and cationic acrylic resin. Commercially available cationic styrene-butadiene rubber that can be used as a cationic polymer dispersion includes "Celtal" manufactured by Daicel FineChem Co., Ltd. Commercially available cationic acrylic resin that can be used as a cationic polymer dispersion includes "CellCation" manufactured by Daicel FineChem Co., Ltd.

Epoxy resin mortar is, for example, a mortar that is a mixture of epoxy resin and fine aggregate. An example of a commercially available epoxy resin mortar is "K Mortar" manufactured by Konishi Co., Ltd.

Examples of fine aggregates in the mortar mentioned above include silica sand, river sand, obsidian perlite, perlite perlite, and calcium carbonate powder. The mortar may contain one type of fine aggregate, or two or more types of fine aggregate.

When the adhesion-improving surface of the buried panel 10 is the surface of a hardened mortar layer, the thickness of the hardened mortar layer is preferably 0.5 mm or more, more preferably 1 mm or more, and even more preferably 1.5 mm or more, from the perspective of ensuring high adhesive strength to the concrete raw material. Furthermore, from the perspective of reducing the weight and improving workability of the buried panel 10, and from the perspective of reducing the manufacturing and transportation costs of the buried panel 10, the thickness of the hardened mortar layer is preferably 10 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less.

When polymer cement mortar or cationic mortar is applied to a fiber-reinforced cement board, much of the water in the applied mortar is absorbed by the fiber-reinforced cement board, causing the mortar to dry out. Mortar in a dry-out state can inhibit the hydration reaction, resulting in poor hardening and adhesion. To prevent this dry-out, it is preferable to adjust the fiber-reinforced cement board's water absorption before applying the mortar. Methods for adjusting water absorption include spraying water onto the fiber-reinforced cement board and applying a water absorption regulator to the fiber-reinforced cement board. Examples of such water absorption regulators include water absorption regulators for cement mortar coatings, which are primarily composed of synthetic resin emulsions or polymer dispersions. Examples of synthetic resins used in such water absorption regulators include acrylic resins, vinyl acetate resins, ethylene vinyl acetate resins, and synthetic rubbers. Commercially available water absorption regulators for use on cement mortar include, for example, "Cellmighty 10," "Celltite 10," "Celllock J," and "Cell Primer J" manufactured by Daicel FineChem Ltd., "HOUN Sealer N" manufactured by Houn Co., Ltd. (all of which contain ethylene vinyl acetate resin), and "Multi Primer" and "Pertus AC-300" manufactured by Showa Denko Kenzai Co., Ltd. (all of which contain acrylic resin).

The above-mentioned uneven surface serving as the adhesion-improving surface of the embedded panel 10 can be formed, for example, during the manufacturing process of the fiber-reinforced cement board used to form the embedded panel 10, by press-molding or extrusion-molding the fiber-reinforced cement board using a mold such as a template with a predetermined uneven shape on the surface that contacts the area where the adhesion-improving surface is to be formed.

The mechanically roughened surface described above as the adhesion-improving surface of the embedded panel 10 can be formed, for example, by roughening the area where the adhesion-improving surface is to be formed on the fiber-reinforced cement board that will form the embedded panel 10 by performing a mechanical roughening process such as sanding or chipping.

The surface 12 of the embedded panel 10 may be provided with a decorative surface or the adhesion-improving surface over part or all of its surface.

If a decorative surface is provided over part or all of the surface 12 of the embedded panel 10, after constructing the concrete structure using the formwork unit X, there is no need to apply a new mortar finish or paint to the outer surface of the embedded panel 10, which is preferable from the standpoint of work efficiency.

If the surface 12 of the embedded panel 10 includes an adhesive-improved surface, the adhesive-improved surface of the embedded panel 12 is suitable for tiling after installation.

The decorative surface may be, for example, a smooth surface, a cured paint film surface, or a surface to which a decorative sheet is attached.

The smooth surface can be formed, for example, during the manufacturing process of the fiber-reinforced cement board to form the embedded panel 10, by press-molding or extrusion-molding the fiber-reinforced cement board using a mold such as a template with a smooth surface that comes into contact with the area where the decorative surface is to be formed. A known example of a panel (fiber-reinforced cement board) with such a smooth surface is the "flexible board (decorative board finish type)," a type of slate board from the Fiber-Reinforced Cement Board Association.

The cured paint film surface can be formed by applying a paint to the portion of the fiber-reinforced cement board that will form the embedded panel 10 where the decorative surface is to be formed, followed by curing. Usable paints include, for example, organic paints, inorganic paints, and organic-inorganic hybrid paints. From the perspective of durability of the resulting cured paint film surface, inorganic paints and organic-inorganic hybrid paints are preferred. Examples of organic paints include acrylic resin paints, epoxy paints, urethane resin paints, fluororesin paints, polyester paints, and vinyl organosol paints. Examples of inorganic paints include alkyl silicate paints, inorganic paints containing photocatalytic titanium oxide, silica sol paints, alkali metal salt paints, metal alkoxide paints, cement lysine paints, and cement stucco paints. Examples of organic-inorganic hybrid paints include organic-inorganic hybrid paints containing siloxane bonds, metal alkoxide paints, ceramic paints, and organic-inorganic hybrid paints containing photocatalytic titanium oxide. These paints may contain other additives in addition to the pigments, such as fillers, thickeners, leveling agents, defoamers, and stabilizers.

Examples of decorative sheets for forming the decorative sheet attachment surface include vinyl chloride decorative sheets, thermoplastic resin decorative sheets, thermosetting resin decorative sheets, thin decorative sheets, and so-called P tiles. Vinyl chloride decorative sheets can be produced, for example, by printing a pattern on an opaque vinyl chloride sheet kneaded with a pigment, heat-adhering a transparent vinyl chloride film to the printed surface, and optionally embossing the printed surface. Embossing can be performed, for example, by applying pressure with a roll having an uneven surface. Thermoplastic resin decorative sheets can be produced in a manner similar to that used for vinyl chloride decorative sheets, except that various plastic resins are used instead of vinyl chloride resin as the sheet constituent resin. Thermosetting resin decorative sheets can be produced by layering decorative paper with a basis weight of 55 to 200 g/ ^m² impregnated with a thermosetting resin such as melamine resin, diallyl phthalate resin, or polyester resin on a base sheet such as kraft paper impregnated with the same thermosetting resin, and then hot-pressing the resulting laminate using a multi-stage hot press or a continuous molding press. The thin decorative sheet can be produced, for example, by applying a colored solid print to tissue paper with a basis weight of approximately 30 g/ ^m² , printing a design on the solid print surface, and then painting the printed surface with an amino alkyd resin paint or polyurethane resin paint. The decorative sheet used to form the decorative sheet attachment surface is preferably a polyvinyl chloride decorative sheet or a P tile. The decorative sheet can be attached to the fiber-reinforced cement board that forms the embedded panel 10 via an adhesive resin such as a urethane resin, vinyl resin, or acrylic resin.

Particularly preferred examples of the embedded panel 10, which is a flat fiber-reinforced cement board as described above, include the one described in Japanese Patent Application Laid-Open No. 8-312092 (which does not contain asbestos) and the "Cell Kekomi Panel" and "Cell Slim Step Board" manufactured by Daicel FineChem Co., Ltd.

When the material of the embedded panel 10 is a material other than fiber-reinforced cement board, i.e., inorganic materials such as thermoplastic resins, thermosetting resins, metals, ceramics, wood, paper, or laminated or mixed materials thereof, methods for providing an adhesion-improving surface include forming an uneven surface 11, roughening the surface using a mechanical or chemical method, embedding an adhesion-improving material that may include a porous or foamed layer into the surface 11, fitting it in with a wooden frame, gluing (melting, hardening), or fastening with screws.

The adhesion improving material, which may include the porous layer or foam layer, may be in the form of a plate, cloth, sponge, or particle aggregate.

The adhesion improving material, which may include the porous layer or foam layer, can be appropriately selected from concrete, glass, ceramic, porcelain, diatomaceous earth, stone, wood, paper, natural fiber, charcoal, thermoplastic resin, and thermosetting resin, depending on the material of the buried panel used.

In particular, when embedding or adhering an adhesion improving material to the embedded panel 10, it is preferable to use a combination that allows for easy adhesion to each other.

For example, for embedded panels made of fiber-reinforced polyurethane, it is preferable to use urethane sponge foam as an adhesion improving material.

Furthermore, if a component that forms a perimeter with a continuous surface is embedded into the surface 11, fitted with a wooden frame, glued (melted and hardened), or fastened with screws, the embedded panel 10 can be fixed to the concrete structure by the hardening of the poured concrete itself.

In particular, when components forming a perimeter with a continuous surface are embedded into surface 11 and fitted with wood joinery, glued (melted, hardened), or fastened with screws, and the stepped structure is 1m or less in height (such as a stepped structure for a modular bath or a stepped structure with a water return function), workers may need to stack and transport multiple buried panels 10. To prevent misalignment even when multiple panels are stacked and to facilitate easy transport without adding bulk, the components forming the perimeter with a continuous surface on the 11 faces of the facing buried panels 10 can be arranged so that they do not overlap. Alternatively, the components forming the perimeter with a continuous surface can be placed in a bag or similar and carried over the shoulder, allowing them to be easily fitted into the buried panel 10 when it is installed.

For example, a thin metal member for fitting can be fixed to a thin plywood board to form a buried panel, and a thin metal member for fitting can also be fixed to a wooden member whose periphery is formed by the continuous surfaces of a square pillar with a hollow center, making it possible to easily perform fitting and fixing work at the construction site.

(Connecting member 20)
The connecting member 20 is a member that extends from the surface 11 of the embedded panel 10 to the inside of the concrete filling section 80 when assembling the formwork unit X to form the concrete filling section 80, and determines the width of the concrete filling section 80.

As shown in Figure 1, the connecting member 20 is a rod-shaped member having a separator portion 21 and a male thread portion 22 provided at one end of the separator portion 21.

The separator section 21 may be straight or may be bent at any number of points.

The length of the separator section 21 can be selected appropriately depending on the width of the concrete-filled section 80.

The male thread portion 22 is a threaded portion that is coaxial with the separator portion 21 and is provided at one end of the separator portion 21. The diameter of the male thread portion 22, i.e., the diameter at the crest of the thread (nominal diameter), is approximately the same as that of the separator portion 21.

The end of the separator portion 21, i.e., the end opposite the end where the male thread portion 22 is provided, is connected to a non-movable portion located inside the concrete filled section 80 when the prefabricated formwork unit Y is assembled to form the concrete filled section 80. The end of the separator portion 21 may be threaded. If the end of the separator portion 21 is threaded, it can be screwed to the non-movable portion.

The length of the male thread portion 22 need only be long enough to threadably engage with the female thread portion 33 of the first fastener 30 and secure the connecting member 20 to the embedded panel 10.

(Tsuba 23)
The flange 23 is a planar member having a hole 24 through which the male thread portion of the second fastener 40 can pass and an end face 23A for abutting against the surface of the buried panel. When assembling the formwork unit X, the hole 24 of the flange 23 is aligned with the opening of the surface 12-side hole of the hole 13 of the buried panel 10, and with the flange 23 abutting against the buried panel 10, the male thread portion of the second fastener 40 is inserted into the hole 13 and hole 24 and screwed to the female thread portion of the first fastener 30, thereby reinforcing the connection between the buried panel 10 and the connecting member 20, and when concrete raw material is filled into the formwork formed by assembling the prefabricated formwork unit Y, this prevents the buried panel 10 from being distorted by the weight of the concrete raw material or a load (e.g., an impact load, etc.). The formwork unit X of the present disclosure includes a flange 23, and therefore has the strength to withstand the weight of the concrete raw materials and loads (e.g., impact loads), and concrete can be poured without reinforcing the formwork with formwork supports.

The number of holes 24 in the flange 23 is at least one, and may be two or more (for example, two to four). When there are two or more holes 24, it is possible to secure two or more adjacent buried panels 10 together. This allows the adjacent buried panels 10 to be firmly joined together, providing durability that can withstand high lateral pressure.

The thickness of the flange 23 is, for example, 2 mm to 20 mm, preferably 3 mm to 10 mm.

There are no particular restrictions on the planar shape of the flange 23, but it may be circular, rectangular, polygonal, etc.

The total contact area of the flange 23 with the surface of the embedded panel and the contact area of the first fixing device with the back surface of the embedded panel is preferably at least 0.5% of one surface area of the embedded panel 10, as this provides excellent reinforcement for the formwork unit X. Furthermore, in order to be able to withstand higher lateral pressures, it is preferable for this total to be at least 2%, and even more preferably at least 5% of one surface area of the embedded panel 10.

Therefore, when form unit X is a form unit that forms a concrete pouring form by assembling multiple embedded panels in a line in the height direction so that they are flush with each other, the sum of the contact area of the flange with the surface of the embedded panel and the contact area of the first fixing device with the back surface of the embedded panel is preferably 5% or more of the surface area of one of the embedded panels 10, more preferably 10% or more, and particularly preferably 20% or more.

It is preferable that the area of the contact surface 23A of the flange 23 against the buried panel 10 (i.e., the area of the protruding portion of the flange 23) be changed appropriately depending on the size of the buried panel 10 and the number of separator portions 21 used per buried panel.
For example, when using an embedded panel 10 with dimensions (length x width) of 200 to 350 mm x 1820 mm and seven connecting members 20 are attached in a zigzag pattern, the area is, for example, 2 to 10%, preferably 3 to 7% (Figure 2(a)).
When using an embedded panel 10 with dimensions (length x width) of 60 to 80 mm x 1820 mm and attaching five connecting members 20 in a row, the protruding area of the flange 23 is, for example, 5 to 15%, preferably 8 to 12% (Figure 2(b)).
When using an embedded panel 10 with dimensions (length x width) of 60 to 80 mm x 1820 mm and attaching four connecting members 20 in a row, the protruding area of the flange 23 is, for example, 5 to 20%, preferably 10 to 18% (Figure 2(c)).

Furthermore, the thinner the embedded panel 10, the greater the area of the contact surface 23A of the flange 23 against the embedded panel 10, thereby reducing the work, time, and cost required to construct the concrete structure, and allowing for simple and speedy operation to form a strong, aesthetically pleasing concrete structure.

The material from which the flange 23 is made is not particularly limited, and can be various metals (e.g., steel, stainless steel, titanium steel), high-rigidity ceramics, thermosetting plastics, thermoplastic engineering plastics, various durable coated materials, etc.

The flange 23 may have color, gloss, a pattern, a surface finish (e.g., unevenness), or intricate details on the surface 23b opposite the surface 23A that contacts the embedded panel 10.

Furthermore, the flange 23 may be provided with hooks on the surface 23b from which lighting fixtures, LCD panels, etc. can be hung. It may also be provided with holes into which the hooks can be attached. There is no particular limit to the number of hooks or holes that can be installed.

(First fixture 30)
The first fastener 30 is a member that is installed on the back side (surface 11 side) of the buried panel 10, and is a member that fixes the connecting member 20 and the second fastener 40 to the buried panel 10.

As shown in Figure 1, the first fastener 30 is a convex member having an end surface 31 for contacting the rear surface of the embedded panel, and the shaft of the convex member has a through-hole with an internal thread 33 that threads onto the external thread 22 of the connecting member 20 and the external thread 42 of the second fastener 40.

5, the first fixing device 30 may include a convex main body 32 and a base 34 provided at one end of the main body. The base 34 has a shape that protrudes from the end of the convex main body 32 in a direction substantially perpendicular to the axial direction of the convex main body 32. The surface of the base 34 opposite to the surface on which the convex main body 32 is provided becomes the embedded panel abutting end surface 31.

The protruding length of the base portion 34 is, for example, approximately 10 to 100 mm, preferably 20 to 50 mm. There are no particular restrictions on the shape of the base portion 34 in plan view, and it can be, for example, circular, rectangular, polygonal, etc.

Furthermore, the sum of the contact area of the flange 23 (or flange-shaped head 44 described below) with the surface of the buried panel 10 and the contact area of the first fixing device 30 with the back surface of the buried panel 10 is preferably 0.5% or more of one surface area of the buried panel 10, in order to provide excellent reinforcing effect for the formwork unit X. Furthermore, in order to be able to withstand higher lateral pressures, it is preferable that this be 2% or more of one surface area of the buried panel 10, more preferably 3.5% or more, and particularly preferably 5% or more.

(Second fixture 40)
The second fastener 40 is a member for fastening the flange 23 to the buried panel 10 from the front side (surface 12 side) of the buried panel 10. As shown in Figure 1, the second fastener 40 has a head 41 and a male threaded portion 42. The male threaded portion 42 is threadedly engaged with the female threaded portion 33 of the first fastener 30.

Then, the second fastener 40 can be fixed to the buried panel 10 by inserting the male threaded portion 42 into the hole 24 of the flange 23, and then inserting it into the hole 13 of the buried panel 10 from the back side (surface 11 side) of the buried panel 10, and then screwing the female threaded portion 33 of the first fastener 30 into the male threaded portion 42 protruding from the front side (surface 12 side) of the buried panel 10.

The head 41 of the second fastener 40 needs only to be of a size that does not pass through the hole 13 in the embedded panel 10.

The length of the male thread portion 42 of the second fastener 40 need only be long enough to threadably engage with the female thread portion 33 of the first fastener 30 and secure the flange 23 to the embedded panel 10.

(Second fixing device with flange)
In the form unit X of the present disclosure, the flange 23 and the second fastener 40 may be included as separate members as described above, or may be included as a single member. That is, the flange 23 and the second fastener 40 may be replaced with a flanged second fastener 43 having a flange-shaped head portion 44 and an external thread portion 42.

The total contact area of the flange-shaped head 44 of the flange-equipped second fastener 43 against the surface of the buried panel 10 and the contact area of the first fastener 30 against the back surface of the buried panel 10 is preferably at least 0.5% of one surface area of the buried panel 10, in order to provide excellent reinforcement for the formwork unit X. Furthermore, in order to be able to withstand higher lateral pressures, it is preferable for it to be at least 2%, more preferably at least 3.5%, and particularly preferably at least 5% of one surface area of the buried panel 10.

As shown in Figure 3, the second flanged fastener 43 is a component having a flange-shaped head 44 and a male thread 42 connected to it. As shown in Figure 3, the number of male threads 42 connected to the flange-shaped head 44 is at least one, but may be two or more (e.g., two to four).

If the flanged second fastener 43 has multiple male threads 42, it can be used across multiple adjacent buried panels 10 to firmly connect the adjacent buried panels 10 and provide durability that can withstand high lateral pressure.

(Connector)
The formwork unit X may further include a connector 50A as shown in FIG. 6( a). The connector 50A is used to connect two adjacent embedded panels 10, which are assembled during the construction of a concrete structure, so that their surfaces 12 are flush with one another. In this embodiment, the connector 50A includes at least a flat plate 51 and a predetermined number of fasteners 52 (FIG. 6( a) exemplarily illustrates a connector 50A including four fasteners 52). When two adjacent embedded panels 10 are connected by the connector 50A, the flat plate 51 is applied across the two adjacent embedded panels 10, for example, to the surfaces 12 (outer surfaces) of the two embedded panels 10. The fasteners 52 are, for example, drill screws. When the fasteners 52 are drill screws, the flat plate 51 across the two adjacent embedded panels 10 is secured by the fasteners 52 inserted from the surface 12 side of the embedded panel into through-holes 13 drilled through the flat plate 51 and each embedded panel 10. In such a connector 50A, the flat plate 51 may be applied to the surface 11 (inner surface) of two adjacent buried panels 10 across the two adjacent buried panels 10, and the fastening material 52 may be a bolt. When the fastening material 52 is a bolt, the flat plate 51 across the two adjacent buried panels 10 is fixed by the bolt (fastening material 52) inserted from the surface 12 side of the buried panel into a through hole 13 drilled so as to penetrate the flat plate 51 and each buried panel 10, and a nut fastened to the threaded portion of the bolt on the surface 11 side.

Providing such connectors 50A on formwork unit X is preferable for properly forming a flat sidewall surface spanning multiple embedded panels 10 in the concrete structure formed using formwork unit X. Furthermore, after forming the sidewall surface using such connectors 50A, the fastening materials 52 and, if a flat plate 51 is attached to surface 12, the flat plate 51 can be removed from the sidewall surface, and the relatively small embedded panel through-holes 13 where the fastening materials 52 were inserted can be repaired by filling at least the outer opening ends with mortar, thereby ensuring a good aesthetic appearance for the sidewall surface.

The number of fasteners 52 provided in one set of connectors 50A is four in FIG. 6(a), but may be two, three, five, or more. Also, the number of connectors 50A used to connect two adjacent embedded panels 10 in one set is one in FIG. 6(a), but may be two, three, or more.

Instead of the connector 50A shown in Figure 6(a), the formwork unit X may be equipped with a flat joiner (or H-joiner), for example, as shown in Figure 12(a) of Japanese Patent Publication No. 4103729.

The formwork unit X may further include a connector 50B as shown in Fig. 6(b). The connector 50B is used to connect two adjacent embedded panels 10 assembled during the construction of a concrete structure so that they are perpendicular to each other or so that their surfaces 11 intersect, and in this embodiment includes at least a bent plate 53 and a predetermined number of fastening members 54 (Fig. 6(b) exemplarily shows a connector 50B including four fastening members 54). When two adjacent embedded panels 10 are connected by the connector 50B, the bent plate 53 is applied across the two adjacent embedded panels 10, for example, to the surfaces 12 (outer surfaces) of the two panels. The fastening members 54 are, for example, drill screws. When the fastening members 54 are drill screws, the bent plates 53 are fixed across two adjacent buried panels 10 by the fastening members 54 inserted from the surface 12 of the buried panels into the through holes 13 drilled so as to penetrate the bent plates 53 and each buried panel 10. In such a connector 50B, the bent plates 53 may be applied to the surface 11 (inner surface) of the two adjacent buried panels 10, or the fastening members 54 may be bolts. When the fastening members 54 are bolts, the bent plates 53 are fixed across two adjacent buried panels 10 by the bolts (fastening members 54) inserted from the surface 12 of the buried panels into the through holes 13 drilled so as to penetrate the bent plates 53 and each buried panel 10, and nuts fastened to the threaded portions of the bolts on the surface 11 side.

Providing such connectors 50B on formwork unit X is preferable for properly forming sidewall surfaces, including adjacent planes that are connected laterally and form a predetermined angle, such as a right angle, in the concrete structure formed using formwork unit X. Furthermore, after forming the sidewall surface using such connectors 50B, the fasteners 54 and, if a bent plate 53 is attached to face 12, the bent plate 53 can be removed from the sidewall surface, and the relatively small embedded panel through-holes 13 into which the fasteners 54 were inserted can be repaired by filling at least the outer opening ends with mortar, thereby ensuring a good aesthetic appearance for the sidewall surface.

The number of fasteners 54 provided in one set of connectors 50B is four in FIG. 6(b), but may be two, three, five, or more. Also, the number of connectors 50B used to connect two adjacent embedded panels 10 in one set is one in FIG. 6(b), but may be two, three, or more.

The two embedded panels 10 shown in Figure 6(b) are arranged to form a stepped portion including an external corner of a concrete structure (an arrangement in which a stepped portion including an external corner is formed on the side of the surface 11 where the adhesion-improved surface is provided). In contrast, when the front side (surface 12 side) and back side (surface 11 side) of each embedded panel 10 shown in Figure 6(b) are swapped, the arrangement of the two embedded panels 10 is an arrangement in which a stepped portion including an internal corner of a concrete structure (an arrangement in which a stepped portion including an internal corner is formed on the side of the surface 11 where the adhesion-improved surface is provided).

Instead of the connector 50B as shown in Figure 6(b), the formwork unit X may be equipped with an outside corner joiner (or inside corner joiner, L-shaped joiner), for example, as shown in Figure 12(b) of Japanese Patent Publication No. 4103729.

Outside corner joiners, made for example from aluminum or polyvinyl chloride resin, are commercially available from companies such as Soken Co., Ltd., Fukubi Chemical Industry Co., Ltd., Shinwa Co., Ltd., and Sato Kozai Co., Ltd., and these can be used.

(Height adjustment tool)
The formwork unit X may further include a height adjuster 60A as shown in Figures 7(a) and 7(b). This configuration is preferable for accurately positioning the embedded panel 10 at the assembly height when constructing a concrete structure using the formwork unit X.

The height adjustment device 60A is used to adjust the height position of the embedded panel 10 that is assembled during the construction of a concrete structure, and includes a support member 61 and a leg member 62 that supports the support member 61.

In this embodiment, the receiving member 61 has a groove for receiving the buried panel 10 that is wider than the thickness of the buried panel 10. Alternatively, the receiving member 61 may not have a groove for receiving the buried panel. For example, the receiving member 61 may have a flat plate of various shapes as a buried panel abutment portion. The flat plate may have an upward folded structure that abuts against the surface 11 or 12 of the buried panel and helps to position the buried panel 10. Alternatively, the receiving member 61 may have a buried panel support rod-shaped member as a buried panel abutment portion. The rod-shaped member may have an upward folded structure that abuts against the surface 11 or 12 of the buried panel and helps to position the buried panel 10, or may be V-shaped or U-shaped. These configurations in which the receiving member 61 does not have the above-mentioned groove are preferred from the viewpoint of ensuring flexibility in the installation location and orientation of the buried panel 10 when assembling it.

The back surface of the receiving member 61 (the surface opposite to the surface that receives the embedded panel 10) preferably has a thread structure or nut portion for connecting to the leg member 62. In Figure 7(a), a thread structure extending vertically from the back surface of the receiving member 61 is provided.

The leg member 62 is a member that supports the receiving member 61. Furthermore, the leg member 62 may have any configuration as long as it is capable of performing the function of adjusting the height position of the embedded panel 10 using the height adjustment device 60A. The leg member 62 includes at least a rod-shaped member.

The rod-shaped member can be a separator, such as that used in the connecting member 20 described above, or two or more separators connected via connecting fittings 63, 66 (e.g., turnbuckles or joint nuts).

One end of the rod-shaped member preferably has a threaded structure or nut for connecting to the receiving member 61. The other end of the rod-shaped member preferably has a base with a predetermined shape and structure suitable for contacting an existing floor surface, etc. In Figure 7(a), one end of the rod-shaped member has a nut, and a threaded structure extending vertically from the back surface of the receiving member 61 is threadedly engaged with the nut, while the other end is supported by a pyramidal base that contacts the floor surface.

Alternatively, the leg member 62 may be a base having a support end face suitable for abutting against an existing flat floor surface and a threaded hole opening on the side opposite the end face, into which one end of a double-ended bolt or a bar screw is threaded, and the other end of the base forms the threaded structure. An example of a base having a support end face and a threaded hole is the first fixture 30 shown in Figure 5. The leg member 62 is constructed by installing the base portion 34 of the first fixture 30 so that it abuts against the flat floor surface, and then threading a double-ended bolt or a bar screw into the female thread portion 33 on the convex body 32.

Alternatively, the leg member 62 may be a rod-shaped member having the other end embedded in existing concrete (a so-called anchor bolt), or a rod-shaped member having the other end welded to a steel member such as a steel frame or rebar, or a rod-shaped member having the other end connected to a steel member such as a steel frame or rebar via a connecting fitting. Examples of the connecting fittings include "Sepa Grip" sold by Okabe Co., Ltd., "SK Univa" and "Domaster" sold by Kyoei Seisakusho Co., Ltd., "Tetsukabuto (with nut)" sold by Nippon Temporary Construction Co., Ltd., "KS Guts" sold by Kunimoto Shokai Co., Ltd., "Sepajime" sold by Inui Sangyo Co., Ltd., "Wire Clip KM Clip" sold by Kondotec Co., Ltd., the "Joint fitting for connecting a separator to a reinforcing bar or round bar" described in JP 2008-214911 A, and the "Connecting fitting for connecting a reinforcing bar to a separator" described in JP 2003-013600 A.

Figures 7(a) and 7(b) show an example of a height adjustment device 60A having two pairs of leg members 62; the height adjustment device 60A may have one pair of leg members 62, or three or more pairs of leg members 62.

The height adjustment device 60A shown in Figure 7(b) supports two adjacent buried panels 10 in a connected state and simultaneously performs the height adjustment function for these buried panels 10. Providing such a height adjustment device 60A on the formwork unit X is preferable for accurately positioning the assembly height of the buried panels 10 when constructing a concrete structure using the formwork unit X.

The formwork unit X may further include a height adjuster 60B as shown in Figure 7(c). The height adjuster 60B is used to adjust the height of two adjacent embedded panels 10 that are to be assembled during the construction of a concrete structure while connecting the two adjacent embedded panels 10 so that their surfaces 11 intersect at a predetermined angle, such as a right angle, and includes a receiving member 64 and a leg member 65 that supports the receiving member 64. Providing such a height adjuster 60B on the formwork unit X is preferable for accurately positioning the assembly height of two adjacent embedded panels 10 that intersect when constructing a concrete structure using the formwork unit X.

In this embodiment, the receiving member 64 has a groove for receiving the buried panel that is wider than the thickness of the buried panel 10. Alternatively, the receiving member 64 may not have a groove for receiving the buried panel. For example, the receiving member 64 may have a flat plate of various shapes as a buried panel abutment. The flat plate may have an upwardly folded structure that abuts against surface 11 or surface 12 of the buried panel and can also be used to determine the position of the buried panel 10. Alternatively, the receiving member 64 may have a rod-shaped member for supporting the buried panel as a buried panel abutment. These configurations in which the receiving member 64 does not have the above-mentioned groove are preferable from the perspective of ensuring freedom of assembly location and orientation when assembling the buried panel 10.

Figure 7(c) shows an example of a height adjustment device 60B having three sets of leg members 65. The height adjustment device 60B may have one set of leg members 65, two sets of leg members 65, or four or more sets of leg members 65. The configuration of the leg members 65 in the height adjustment device 60B is the same as the configuration of the leg members 65 in the height adjustment device 60A.

[Assembly formwork unit]
The prefabricated formwork unit Y of the present disclosure is a prefabricated formwork unit that forms a formwork for pouring concrete without using formwork shoring, and is formed by assembling the above-mentioned formwork units X.

As shown in Figures 8 to 10, the prefabricated formwork unit Y is constructed by inserting the male threaded portion 42 of the second fastener 40, with the flange 23 sandwiched between them, into the hole 13 of the buried panel 10 from the front side of the buried panel 10, and screwing the male threaded portion 42 of the second fastener 40 protruding from the back side of the buried panel 10 and the male threaded portion 22 of the connecting member 20 into the female threaded portion 33 of the first fastener 30, whose end face abuts against the back side of the buried panel 10.

As long as the prefabricated formwork unit Y has the above structure, there are no particular restrictions on the assembly procedure.

When formwork unit X includes a flanged second fastener 43 instead of the flange 23 and second fastener 40, the assembled formwork unit Y is configured as shown in Figure 9, with the male threaded portion 42 of the flanged second fastener 43 inserted into the hole 13 of the buried panel 10 from the front side of the buried panel 10, and the male threaded portion 42 of the second fastener 40 protruding from the back side of the buried panel 10 and the male threaded portion 22 of the connecting member 20 screwed together by the female threaded portion 33 of the first fastener 30, whose end face abuts against the back side of the buried panel 10.

There is no particular limit to the number of connecting members 20 that can be attached to one embedded panel 10, but it may be, for example, 1 to 5. Furthermore, the connecting members 20 may be attached in a line, at the four corners, at the four corners and in the center, or in a zigzag pattern.

After the prefabricated formwork unit Y is assembled in the designated position, the end of the separator portion 21 of the connecting member 20 extending from the surface 11 of the embedded panel 10 can be connected to a non-movable portion located inside the concrete filling section 80, thereby easily fixing the prefabricated formwork unit Y and forming a formwork that defines the section into which the concrete raw materials will be filled.

[Concrete structure construction method]
The concrete structure construction method of the present disclosure is a method for constructing a concrete structure by pouring concrete using a prefabricated formwork unit Y,
Step 1: placing a prefabricated formwork unit Y at a predetermined position to define a section to be filled with concrete raw materials;
a step 2 of fixing the prefabricated formwork unit Y by connecting the end of the separator portion 21 of the placed prefabricated formwork unit Y to a non-movable portion located inside the concrete filling section 80, thereby forming a formwork;
and step 3 of supplying concrete raw materials into the formed formwork.

In step 1, the prefabricated formwork unit Y is assembled so that the surface 11 including the adhesive-improved surface of the embedded panel 10 faces the inside of the concrete-filled section 80.

It is also preferable that the prefabricated formwork unit Y be positioned so that the embedded panel 10 forms at least one surface selected from the upward surface, downward surface, and side wall surface of the compartment where the concrete raw material will be filled.

In step 2, for example, the end of the separator portion 21 of the prefabricated formwork unit Y extending from the surface 11 side of the embedded panel 10 can be connected to a non-movable portion located inside the concrete filling section 80, thereby fixing the prefabricated formwork unit Y in a predetermined position.

As a method for connecting the end of the separator portion 21 (the end of the separator portion 21 opposite the end having the male thread portion 22) to the non-movable portion, for example, when the prefabricated formwork unit Y is assembled to form the concrete-filled section 80, the end of the separator portion 21 may be fixed to another panel (e.g., an embedded panel 10 and/or a removable panel of another prefabricated formwork unit Y located opposite) that forms the filled section together with the prefabricated formwork unit Y. If existing concrete forms a corner of the filled section together with the prefabricated formwork unit Y, the end of the separator portion 21 may be embedded in the concrete to form a so-called anchor bolt 14. Furthermore, the end of the separator portion 21 may be welded to a steel member, such as a steel frame or rebar, present inside the concrete-filled section 80, or may be connected to the steel member via a connecting metal fitting.

Examples of the connecting fittings include those sold by Okabe Co., Ltd. under the trade name "Sepa Grip," Kyoei Seisakusho Co., Ltd. under the trade name "SK Univa" and "Domaster," Nippon Temporary Construction Co., Ltd. under the trade name "Tetsukabuto (with nut)," Kunimoto Shokai Co., Ltd. under the trade name "KS Guts," Inui Sangyo Co., Ltd. under the trade name "Sepajime," Kondotec Co., Ltd. under the trade name "Wire Clip KM Clip," the "joint fitting for connecting a separator to a reinforcing bar or a round bar" described in JP 2008-214911 A, and the "connecting fitting for connecting a reinforcing bar and a separator" described in JP 2003-013600 A.

For example, if concrete is poured using a prefabricated formwork unit Y including the flange 23 and second fixture 40, a concrete structure will be constructed with the flange 23 exposed on the surface. Depending on the material, the flange 23 may rust when exposed to wind and rain. Therefore, once the concrete has hardened, the second fixture 40 can be removed to remove the exposed flange 23, preventing the surface of the concrete structure from being contaminated by rust. The removed flange 23 can then be reused.

The concrete structure includes a concrete structure with a convex structural portion that protrudes upward, downward, or sideways, and a concrete structure with a convex structural portion that protrudes upward, downward, or sideways. The concrete structure is, for example, at least one structure selected from concrete stairs, rising steps (including, for example, steps for modular baths and steps for water return), thresholds, beams, window frames, ceilings, floors, pillars, walls, retaining walls, parapets, and frames.

The concrete structure is particularly preferably one with a step structure of 1 m or less (for example, a rising step of 1 m or less; a step for a modular bath, a step for water return, a floor step for wiring such as electrical cords or storage, etc.).

Concrete structures cast using a formwork consisting of multiple embedded panels aligned flush in the vertical direction are preferably concrete structures with a thickness of 20 cm or less and a height of 2 mm or less. Examples include thin walls installed on balconies to prevent falls or to separate areas; partition walls for spaces used to store disaster prevention equipment, materials, food, water, etc.; and partition walls for constructing basement spaces that can store emergency power sources, batteries for electric vehicles, spare tires, folding ladders, large tools, etc.

A method of forming a form when the concrete structure is a concrete structure including a downwardly protruding ridge structure such as a beam will be described below with reference to FIG.
The prefabricated formwork unit Y is placed on the surface of the beam 70, and the end of the separator part 21 of the placed prefabricated formwork unit Y is embedded in the beam 70 to form a so-called anchor bolt 14, thereby fixing the prefabricated formwork unit Y and forming a formwork.

The method of forming a formwork when the concrete structure is a concrete structure such as a platform that includes a special shape among upwardly protruding convex structures (more specifically, a shape in which the upper surface of a columnar structure is chamfered, i.e., a shape in which a truncated pyramidal structure is formed on the upper surface of the columnar structure) will be described below with reference to Figures 12 and 13.
First, reinforcing bars (and auxiliary steel frames, if necessary) 81 are placed inside the concrete-filled section 80 .
Next, the prefabricated formwork units Y are placed in positions that surround the sides of the concrete filling section 80 and in positions that cover the top surface of the concrete filling section 80, and the ends of the separator parts 21 of the placed prefabricated formwork units Y are connected to the reinforcing bars or auxiliary steel frames 81. This allows the prefabricated formwork units Y to be fixed, and the formwork can be formed.

Conventionally, to construct a concrete structure with a truncated pyramidal structure formed on the top surface of a columnar structure such as a platform, first, a formwork was formed using removable panels to form the columnar structure, and then concrete was applied to the top surface of the formed columnar structure using a trowel or the like without using formwork to form the truncated pyramidal structure. However, to form a truncated pyramidal structure without using formwork, it was necessary to apply concrete material layer by layer and adjust the upper surface and sidewall surfaces of the applied concrete material so that they match the intended truncated pyramidal structure, repeating this process until the intended height was reached. This was time-consuming and resulted in increased costs. However, if the prefabricated formwork unit Y is used, after assembling the columnar structural portion and the truncated pyramidal structural portion to separate them, concrete raw material is filled to first form the columnar structural portion, and then more concrete raw material is filled in, and the outer periphery of the embedded panel 10 in the prefabricated formwork unit Y, which is fixed as the upper surface of the truncated pyramidal structural portion to be formed, is used as a "contact" (i.e., a reference for the finished mortar surface), and the side portion not covered by the prefabricated formwork unit Y (the dotted line portion in Figure 12) is simply smoothed with a trowel or the like to easily form the truncated pyramidal structural portion, thereby reducing effort and cost and achieving a neat finish.

Furthermore, a formwork can be formed using removable panels to form a columnar structure, and then the prefabricated formwork unit Y of the present disclosure can be used to construct a concrete structure of the shape shown in Figure 12 only on the top surface of the formed columnar structure (the position covering the top surface of the concrete-filled section 80).

A method for forming a form for a concrete structure including a rising step will be described below with reference to FIG.
The assembled formwork unit Y is placed in the riser portion of the rising step with the lower end of the embedded panel 10 of the assembled formwork unit Y embedded below the tread or floor surface 76, and the end of the separator portion 21 of the placed assembled formwork unit Y is connected to reinforcing bars or auxiliary steel frames 81 installed inside the concrete filling section, thereby fixing the assembled formwork unit Y and forming a formwork.

After the formwork is formed, concrete raw material is supplied into the formed formwork. First, in the concrete raw material filling section formed by the prefabricated formwork unit Y, concrete raw material is supplied up to height position H1, which corresponds to the height at which the tread or floor surface 76 will be formed. Thereafter, as necessary, the supplied concrete raw material is compacted to fill it tightly, and the surface of the tread or floor surface 76 is finished with a trowel or the like, and the concrete is then cured and allowed to harden.

Next, in the concrete raw material filling section formed by formwork Y, further concrete raw material is supplied up to height position H2, which corresponds to the height at which the upper surface 77 of the rising step is formed. After this, if necessary, the supplied concrete raw material is compacted to fill it tightly, and the surface of the tread or floor surface 76 is finished with a trowel or the like, and the concrete is cured and then hardened. As a result, the embedded panel 10 of the prefabricated formwork unit Y forms the riser portion of the rising step.

Examples of concrete structures with rising steps include concrete structures with steps to prevent water leakage from modular bathrooms, concrete structures with steps for installing office floor wiring, and concrete structures with ridge structures installed to prevent rainwater from seeping in through gaps in exterior walls (e.g., ALC, ECP, parapets, etc.) when they are installed.

The concrete structure construction method of the present disclosure uses prefabricated formwork units Y that are easy to assemble and do not need to be removed after construction, thereby reducing the work, time, and cost required for constructing a concrete structure. Furthermore, when a concrete structure includes surfaces other than upward-facing surfaces, such as walls, ceilings, and beams, i.e., downward-facing surfaces and side wall surfaces, conventional construction methods have employed a method of forming a concrete structure by applying a thin layer of mortar, allowing the mortar to harden, and then applying additional layers until the desired thickness is achieved, since applying a thick layer at once tends to cause the mortar to peel off. However, the concrete structure construction method of the present disclosure makes it possible to form a concrete structure having a desired thickness by simply filling concrete once into a form formed by prefabricated formwork units Y that are firmly fixed to steel frames or the like that form the foundation and framework of the concrete structure. Furthermore, when the concrete structure after construction includes side wall surfaces such as walls or downward surfaces such as the bottom surfaces of ceilings or beams, conventional construction methods have resulted in the side wall surfaces or downward surfaces collapsing due to earthquakes or the like. However, with the concrete structure construction method disclosed herein, as described above, the prefabricated formwork units Y, which are firmly fixed to the steel frames or the like that form the foundation and framework, cover the surface of the concrete structure, thereby preventing the side wall surfaces or downward surfaces of the concrete structure from collapsing due to earthquakes or the like.

Furthermore, according to the concrete structure construction method disclosed herein, the prefabricated formwork unit Y does not need to be removed after construction. Therefore, when constructing a concrete structure having a step portion (a step structure consisting of a first upward surface, a second upward surface, and a side wall surface between these two upward surfaces), the prefabricated formwork unit Y that defines the side wall surface can be assembled without leaving a gap between it and the first upward surface. Specifically, the prefabricated formwork unit Y can be assembled so that the height of the lower end of the embedded panel 10 is the same as or lower than the above-mentioned height position H1. This prevents concrete material from leaking through gaps, eliminates the need to scrape off excess concrete formed by the leaked concrete material, and subsequently repair the scraped-off area as needed, thereby reducing the work, time, and cost required for construction.

Furthermore, because the concrete structure construction method disclosed herein uses prefabricated formwork units Y, the strength of the concrete structure can be maintained without installing rebar as densely as in the past. Therefore, by reducing the installation density of the rebar, the concrete raw materials can be filled more smoothly into the formwork, and compaction can also be performed using a ram, rod-shaped vibrator, or formwork vibrator. This prevents the formation of small pieces of brittle material in the concrete structure, resulting in a concrete structure with excellent strength and aesthetics.

When constructing a concrete structure using prefabricated formwork unit Y, as described above, the embedded panels 10 are integrated with the concrete structure being constructed to form the side wall surfaces. Furthermore, the embedded panels 10 of prefabricated formwork unit Y do not require removal after construction.

Furthermore, as described above, the prefabricated formwork unit Y does not require removal after construction, and therefore can be assembled securely when forming the formwork that defines the concrete raw material filling section 80. Furthermore, the use of the prefabricated formwork unit Y can prevent distortion of the embedded panel 10 when pouring concrete. While conventional construction methods require formwork shoring to prevent distortion of removable panels when pouring concrete, the use of the prefabricated formwork unit Y makes it possible to avoid the need for formwork shoring.

As described above, the prefabricated formwork unit Y is suitable for reducing the work, time, and costs required for constructing concrete structures.

[Method for repairing concrete structures]
The concrete structure repair method of the present disclosure is a method for repairing a concrete structure by pouring concrete using a prefabricated formwork unit Y,
A step 1' of fixing an end of the separator portion 21 of the prefabricated formwork unit Y to a surface to be repaired of a concrete structure to form a formwork;
and step 2' of supplying concrete raw materials into the formed formwork.

Step 1' will be described with reference to Figure 15. In step 1', the prefabricated formwork unit Y is positioned so as to face the surface 73 to be repaired of the concrete structure (window frame 72 in Figure 15), and the end of the separator portion 21 (more specifically, the separator portion 21 fixed in an upright state in a substantially vertical direction) of the prefabricated formwork unit Y extending from the surface 11 of the embedded panel 10 is fixed to the surface 73 to be repaired of the concrete structure, thereby forming a formwork that defines the concrete filling section 80.

Methods for fixing the end of the separator portion 21 to the surface 73 of the concrete structure to be repaired include, for example, embedding the end of the separator portion 21 into the surface 73 of the concrete structure to be repaired to form a so-called anchor bolt 14, or welding the end of the separator portion 21 to a steel member such as a steel frame or rebar, or connecting it to a steel member such as a steel frame or rebar via a connecting fitting.

The concrete structure repair method disclosed herein uses prefabricated formwork units Y that are easy to assemble and do not need to be removed after construction, thereby reducing the work, time, and cost required to repair a concrete structure. Furthermore, when the surface to be repaired of a concrete structure is a wall, ceiling, or other such surface, conventional construction methods involve applying a thin layer of concrete using a trowel or other tool, and then adding additional layers of concrete once the concrete has hardened, as this can cause peeling. However, the concrete structure repair method disclosed herein makes it possible to create a concrete structure repair section of a predetermined thickness by simply filling concrete once into the concrete-filled section 80 formed by prefabricated formwork units Y that are firmly fixed to the steel frames or other components that form the foundation or framework of the concrete structure.

Furthermore, when the surface to be repaired of a concrete structure is a downward-facing surface such as the side surface of a wall or the bottom surface of a ceiling or beam, conventional construction methods have resulted in the repaired portion of the concrete structure peeling off or collapsing after hardening due to earthquakes, etc. However, with the concrete structure construction method disclosed herein, as described above, the prefabricated formwork units Y, which are firmly fixed to the steel frames that form the foundation and framework, cover the surface of the concrete structure, preventing the repaired portion from peeling off or collapsing due to earthquakes, etc.

The "concrete structure repair portion" refers to the portion formed by repair on the surface of the concrete structure to be repaired, and the concrete structure repair portion formed by the concrete structure repair method disclosed herein is formed from the prefabricated formwork unit Y and concrete.

Furthermore, because the concrete structure renovation construction method disclosed herein uses prefabricated formwork units Y, the strength of the renovated area can be maintained even if the reinforcement is not as dense as in the past, or even if reinforcement is omitted. Therefore, by reducing the reinforcement density or omitting reinforcement, the concrete raw materials can be filled more smoothly into the formwork, and compaction can also be performed using a ram, rod-shaped vibrator, or formwork vibrator. This prevents the formation of small pieces of brittle material (so-called junk) in the renovated concrete structure, improving its strength and aesthetics.

[Concrete structures]
In the concrete structure of the present disclosure, the embedded panel 10 included in the prefabricated formwork unit Y forms at least one surface selected from the top surface, bottom surface, and side surface of the concrete structure. The top surface includes an oblique top surface, and the bottom surface includes an oblique bottom surface.

The concrete structures disclosed herein include concrete structures that include a convex structural portion that protrudes upward, downward, or laterally, and concrete structures that include a convex structural portion that protrudes upward, downward, or laterally. The concrete structures disclosed herein are, for example, at least one type of structure made of concrete selected from stairs, thresholds, beams, window frames, ceilings, floors, columns, walls, retaining walls, parapets, and scaffoldings.

The concrete structure of the present disclosure has a prefabricated formwork unit Y that is firmly fixed to the steel frame or other components that form the foundation or framework of the concrete structure, covering at least one surface selected from the top, bottom, and side of the concrete structure, eliminating the risk of concrete peeling and preventing collapse due to earthquakes, etc. Furthermore, the surface 12 of the embedded panel 10 included in the prefabricated formwork unit Y is exposed on the surface of the concrete structure, and if a decorative surface, for example, is formed on said surface 12, it will have a beautiful appearance.

The above configurations and combinations of the present disclosure are merely examples, and additions, omissions, substitutions, and modifications of the configurations may be made as appropriate without departing from the spirit of the present disclosure. Furthermore, the present disclosure is not limited to the embodiments, but is limited only by the claims.

The present disclosure will be explained in more detail below using examples, but the present disclosure is not limited to these examples.

Example 1
The concrete pouring was carried out at the same time as the concrete pouring for the floor construction of the apartment building floor where the unit bath would be installed, using the assembled formwork units shown below.
The following formwork units were used:
Buried panels: Five "Cell Slim Step Boards" manufactured by Daicel FineChem Co., Ltd. (longitudinal dimensions × lateral dimensions × thickness dimensions = 1820 mm × 200 mm × 6.5 mm, number of holes: 7, hole positions: positions shown in Figure 2(a)) were used.
First fixing tool: Seven KP Kondannetsu pads (area of end face for contacting the back surface of buried panel: 19.6 cm ² /piece) manufactured by Sankyo Tech Co., Ltd. were used per buried panel.
Second fixing device with flange: Slim head screws with flange (area of end face for contacting the buried panel surface: 1.3 cm ² /piece) were used, 7 pieces per buried panel.
In addition, predetermined connecting members were used.
In this case, the sum of the contact area of the flange portion with the embedded panel and the contact area of the first fastener with the embedded panel was 4% of one surface area of the embedded panel.

As a result, when the specified amount of concrete was poured using the specified method, no chipping or repair work was required due to concrete overflowing from the formwork units. Furthermore, the shape and dimensions of the space formed by the formwork units were as designed.

On the same day, almost no chipping occurred at the construction site where unit baths were being installed in all rooms in the apartment building on the same floor. Furthermore, at construction sites in different locations, no chipping or repair work was required under the same conditions.

Example 2
The same procedure as in Example 1 was carried out except that six KP Kondannetsu pads were used per buried panel. As a result, although there was almost no change in the workload, a small amount of chipping work occurred.

Example 3
The concrete pouring for the construction of a water return step in an apartment building or other collective housing complex was carried out using the assembled formwork units described below. The concrete pouring was carried out at the same time as the concrete pouring for the construction of the floor of the collective housing complex where the water return step would be installed.
The following formwork units were used:
Buried panels: Six "Cell Slim Step Boards" manufactured by Daicel FineChem Co., Ltd. (longitudinal dimensions × lateral dimensions × thickness dimensions = 1820 mm × 60 mm × 6.5 mm, number of holes: 5, hole positions: positions shown in Figure 2(b)) were used.
First fixing tool: KP Kondannetsu Pad (area of end face for contacting the back surface of buried panel: 19.6 cm ² /piece) manufactured by Sankyo Tech Co., Ltd., five of each were used per buried panel.
Second fixing device with flange: Five slim head screws with a flange of 20 mm (area of the end face for contacting the buried panel surface: 1.3 cm ² /piece) were used per buried panel.
In addition, predetermined connecting members were used.
In this case, the sum of the contact area of the flange portion with the embedded panel and the contact area of the first fastener with the embedded panel was 10% of one surface area of the embedded panel.

As a result, when the specified amount of concrete was poured using the specified method, no chipping or repair work was required due to concrete overflowing from the formwork units. Furthermore, the shape and dimensions of the space formed by the formwork units were as designed. Furthermore, even at construction sites in different locations, no chipping or repair work was required under the same conditions.

Example 4
The same procedure as in Example 3 was carried out except that four KP Kondannetsu pads were used per buried panel. As a result, although there was almost no change in the workload, a small amount of chipping work occurred.

<Embodiment 2>
Next, a second embodiment of the present disclosure will be described. The following describes a formwork unit X′ (prefabricated formwork unit Y′) in which a plurality of embedded panels 10 are unitized so as to be arranged facing each other at intervals, and a method for constructing a concrete structure using the same.

Figures 16 and 17 are diagrams illustrating the prefabricated formwork unit Y' according to embodiment 2. Figure 16 shows the prefabricated formwork unit Y' as viewed from above. Figure 17 shows the prefabricated formwork unit Y' as viewed from the side (as viewed from the direction of arrows A-A in Figure 16).

The prefabricated formwork unit Y' is installed at the boundary between the first slab construction area A1 and the second slab construction area A2, where the slabs will be constructed. The prefabricated formwork unit Y' is an assembly formed by assembling formwork units X' shown in Figure 19, and is used to construct a convex raised step (step structure) on the top surface of the slab when the slab is constructed. Here, as an example, we will explain how a step structure including a raised portion for a sash frame and a raised portion for a balcony water return is constructed in one shot (by pouring concrete once) at the boundary between the prefabricated formwork unit Y' and the slab on the indoor side (hereinafter sometimes referred to as the "first slab area") S1 and the balcony side slab (hereinafter sometimes referred to as the "second slab area") S2 during concrete pouring.

Reference numeral 100 in FIG. 16 denotes an existing steel pipe column. Reference numeral ST in FIGS. 16 and 17 denotes slab reinforcement arranged in the first slab construction area A1 and the second slab construction area A2. In FIGS. 16 and 17, the slab reinforcement ST is shown schematically, and in FIG. 17, only a portion of the slab reinforcement ST is partially illustrated for drawing purposes. The slab reinforcement ST is placed on a foundation 101 (see FIG. 17) via appropriate spacers 101A, and rebar is typically assembled in a grid pattern. The foundation 101 supports a concrete structure constructed using the prefabricated formwork unit Y' and serves as an existing base onto which concrete for constructing the concrete structure is poured. For example, the foundation 101 may be an existing half-precast deck slab. After the upper end reinforcing bars (slab reinforcement ST) of the indoor side slab S1 and the balcony side slab S2 are placed on the half-precast deck slab, the concrete raw material is poured to construct a slab integrated with the half-precast deck slab. The reinforcing bar diameter and reinforcing pitch of the slab reinforcement ST may be different between the first slab construction area A1 and the second slab construction area A2. The base 101 is not particularly limited and may be, for example, a deck plate. When constructing a dirt slab, the base 101 may be the ground or basin concrete laid on the ground.

Figure 18 is a diagram illustrating a concrete structure constructed using the prefabricated formwork unit Y' according to embodiment 2. As shown in Figure 18, the concrete structure constructed using the prefabricated formwork unit Y' is constructed as a slab (indoor-side slab S1 and balcony-side slab S2) with a raised concrete step 110 protruding from its upper surface. The raised step 110 includes a first step portion 120 located on the indoor side and a second step portion 130 located on the balcony side and connected to the first step portion 111. Here, the first step portion 120 is formed as a raised portion for a sash frame, which serves as a support for attaching a sash frame. Meanwhile, the second step portion 130 is formed as a raised portion for a balcony water return that rises from the top surface of the balcony-side slab S2 to prevent rain and water from entering the indoor side from the balcony side. However, the uses and functions of the first step portion 120 and second step portion 130 that make up the rising step 110 are illustrative and are not particularly limited. As shown in Figure 18, the first step portion 120 (rising portion for a sash frame) and the second step portion 130 (rising portion for a balcony water return) in the rising step 110 have different upper surface heights. In other words, the rising step 110 can be said to be a composite step structure that includes multiple step portions with different upper surface heights.

In Figure 18, symbol SH1 denotes the upper surface of the indoor slab S1. Symbol SH2 denotes the upper surface of the balcony slab S2. Symbol 111 denotes the upper surface of the sash frame formed as the upper surface of the first step portion 120 (sash frame rising portion) in the rising step 110. Symbol 112 denotes the upper surface of the balcony step formed as the upper surface of the second step portion 130 (balcony water return rising portion) in the rising step 110. Symbol 113 denotes the side surface rising from the indoor slab upper surface SH1 at the boundary between the indoor slab S1 and the first step portion 120 (sash frame rising portion), and is the first side surface connecting the indoor slab upper surface SH1 and the sash frame surface 111. Reference numeral 114 denotes a side surface rising from the balcony-side slab upper surface SH2 at the boundary between the balcony-side slab S2 and the second step portion 130 (rising portion for balcony water return), and is a second side surface connecting the balcony-side slab upper surface SH2 and the balcony step upper surface 112. Reference numeral 115 denotes a third side surface rising from the balcony step surface 112 at the boundary between the first step portion 120 (rising portion for sash frame) and the second step portion 130 (rising portion for balcony water return) in the rising step 110, and is connecting the balcony step upper surface 112 and the sash frame upper surface 111.

Here, the respective heights of the indoor slab top surface SH1, balcony slab top surface SH2, balcony step top surface 112, and sash frame top surface 111 are referred to as the first top surface height L1 to the fourth top surface height L4. In this embodiment, the first top surface height L1 of the indoor slab top surface SH1 and the second top surface height L2 of the balcony slab top surface SH2 are designed to be the same height, but the first top surface height L1 and the second top surface height L2 may be different. Also, as shown in Figure 18, the fourth top surface height L4 of the sash frame top surface 111 is set at a position one step higher than the third top surface height L3 of the balcony step top surface 112.

Next, the detailed structure of the prefabricated formwork unit Y' will be described.
This unit assembly includes a first buried panel 10(A), a second buried panel 10(B), and a third buried panel 10(C), and these three buried panels 10 are assembled in parallel with a gap between them. As shown in Figure 16, the first buried panel 10(A) to the third buried panel 10(C) in the prefabricated formwork unit Y' extend along the boundary between the first slab construction planned area A1 and the second slab construction planned area A2. The first buried panel 10(A) to the third buried panel 10(C) are assembled with a gap between them in the order of the first buried panel 10(A), the third buried panel 10(C), and the second buried panel 10(B) from the side of the first slab construction planned area A1.

The first buried panel 10(A) is a buried panel that forms the first side surface 113 of the rising step 110. The second buried panel 10(B) is a buried panel that forms the second side surface 114 of the rising step 110. The third buried panel 10(C) is a buried panel that forms the third side surface 115 of the rising step 110. As shown in FIG. 17, the height dimension from top to bottom of each buried panel 10(A) to (C) is the largest for the first buried panel 10(A), the next largest for the second buried panel 10(B), and the smallest for the third buried panel 10(C). The distance between the first buried panel 10(A) and the third buried panel 10(C) is not particularly limited, but may be set in the range of 50 to 200 mm, for example. Furthermore, the distance between the first buried panel 10(A) and the second buried panel 10(B) is not particularly limited, but may be set to a distance that is, for example, approximately 50 to 300 mm larger than the distance between the first buried panel 10(A) and the third buried panel 10(C).

In the embodiment shown in Figure 17, the lower ends 15A, 15B of the first buried panel 10(A) and the second buried panel 10(B) are aligned in height, with their surfaces (back surfaces) 11 facing each other. The upper ends 16A, 16C of the first buried panel 10(A) and the third buried panel 10(C) are aligned in height, with the surface (back surface) 11 of the upper region of the first buried panel 10(A) facing the surface (back surface) 11 of the third buried panel 10(C). As shown in Figure 17, the first buried panel 10(A) and the second buried panel 10(B) are connected and fixed via connecting member 20A to maintain a predetermined distance, and the first buried panel 10(A) and the third buried panel 10(C) are connected and fixed via connecting member 20B to maintain a predetermined distance. In the prefabricated formwork unit Y', the surface (back surface) 11 of each embedded panel 10(A)-(C) is arranged facing the inside of the concrete-filled section 80' defined by each embedded panel 10(A)-(C). As in the above-described embodiment, the surface (back surface) 11 of each embedded panel 10(A)-(C) may be provided with an adhesion-improving surface. Since the adhesion-improving surface has already been described in the above-described embodiment, a description thereof will be omitted here.

In the prefabricated formwork unit Y' of this embodiment, the first embedded panel 10(A) forming the first side surface 113 of the rising step 110 is positioned and fixed so that its lower end 15A is positioned at the same height as the first upper surface height L1 or lower than the first upper surface height L1 (the latter embodiment is shown in Figure 17). The second embedded panel 10(B) forming the second side surface 114 of the rising step 110 is positioned and fixed so that its lower end 15B is positioned at the same height as the second upper surface height L2 or lower than the second upper surface height L2 (the latter embodiment is shown in Figure 17). The third embedded panel 10(C) forming the third side surface 115 of the rising step 110 is positioned and fixed so that its lower end 15C is positioned at the same height as the third upper surface height L3 or lower than the third upper surface height L3 (the latter embodiment is shown in Figure 17). Additionally, the upper end 16B of the second embedded panel 10(B) is positioned at the same height as the third upper surface height L3, and the upper ends 16A, 16C of the first embedded panel 10(A) and the third embedded panel 10(C) are positioned at the same height as the fourth upper surface height L4.

Figure 19 is a diagram showing a form unit X' before assembly into a prefabricated form unit Y' according to embodiment 2. The connecting member 20A connecting the first embedded panel 10(A) and the second embedded panel 10(B) has a separator portion 21 and male thread portions 22 provided on both ends of the separator portion 21, and the above-mentioned first fasteners 30 are attached to each male thread portion 22. In other words, the connecting member 20A has substantially the same structure as the connecting member 20 shown in Figure 1, except that the separator portion 21 has male thread portions 22 provided on both ends of the separator portion 21.

The connecting member 20B connecting the first buried panel 10(A) and the third buried panel 10(C) is similar to the connecting member 20A described above, except that the separator portion 21 has a different length. In this embodiment, the connection between the buried panel 10 and each connecting member 20A, 20B is reinforced by a flanged second fastener 43, which has an integral flange-shaped head portion 44 and male thread portion 42. However, instead of the flanged second fastener 43, a second fastener 40 having a separate head portion 41 and male thread portion 42 may be used. Each buried panel 10(A) to (C) is similar to the buried panel 10 of the embodiment described above, and has through holes formed in appropriate locations to allow the male thread portion 42 to pass through.

Figure 20 is a schematic perspective view of the first buried panel 10 (A) according to embodiment 2, viewed from the surface (rear face) 11 side. Figure 21 is a schematic perspective view of the second buried panel 10 (B) according to embodiment 2, viewed from the surface (rear face) 11 side. Figure 22 is a schematic perspective view of the third buried panel 10 (C) according to embodiment 2, viewed from the surface (rear face) 11 side. Here, reference numerals 16A to 16C indicate the upper ends of the buried panels 10 (A) to (C).

First, as shown in FIG. 20, the first buried panel 10(A) has two tiers of through holes. Reference numeral 13A(1) denotes a lower tier through hole formed through the lower tier of the first buried panel 10(A). Reference numeral 13A(2) denotes an upper tier through hole formed through the upper tier of the first buried panel 10(A). The lower tier through holes 13A(1) of the first buried panel 10(A) are arranged in a horizontal row (straight line) at intervals along the width direction (longitudinal direction) of the first buried panel 10(A). Similarly, the lower tier through holes 13A(2) of the first buried panel 10(A) are arranged in a horizontal row (straight line) at intervals along the width direction (longitudinal direction) of the first buried panel 10(A). In the example shown in Figure 20, the first buried panel 10(A) has five lower through holes 13A(1) and five upper through holes 13A(2), and the corresponding lower through holes 13A(1) and upper through holes 13A(2) are arranged vertically. However, the number, position, arrangement pattern, etc. of the lower through holes 13A(1) and upper through holes 13A(2) in the first buried panel 10(A) are not particularly limited, and the example shown in Figure 20 is one example.

As shown in Figure 21, the second buried panel 10(B) has five through holes 13B arranged at intervals in a horizontal row (straight line) along its width direction (longitudinal direction). As shown in Figure 22, the third buried panel 10(C) has five through holes 13C arranged at intervals in a horizontal row (straight line) along its width direction (longitudinal direction). However, the number, position, arrangement pattern, etc. of the through holes 13B and 13C are not particularly limited, and the arrangement shown in Figures 21 and 22 is merely an example.

The male thread portion 42 of the flanged second fastener 43 can be inserted (passed through) into each of the through holes 13A(1), 13A(2), 13B, and 13C of each buried panel 10(A) to 10(C). (If the flanged second fastener 40 is used instead of the flanged second fastener 43, the male thread portion 42, which is separate from the head 41, can be inserted.)

17 and 19 , reference numeral 9 denotes an auxiliary member that holds the lower ends of the first buried panel 10(A) and the second buried panel 10(B). FIG. 23 is a schematic perspective view of the auxiliary member 9 according to the second embodiment. The auxiliary member 9 includes a rectangular strip-shaped base plate 91 and panel fitting portions 92 formed at both ends of the base plate 91 in the long-side direction. Each panel fitting portion 92 of the auxiliary member 9 includes a pair of holding plates 94 that are arranged opposite each other so as to form a holding groove 93 having a predetermined groove width W. Each holding plate 94 of the auxiliary member 9 extends parallel to the width direction (short-side direction) of the base plate 91. Furthermore, the holding plate 94 of each panel fitting portion 92 extends vertically upward from the upper surface 91A of the base plate 91, allowing a buried panel to be fitted into the holding groove 93. The height H of the holding groove 93 of each panel fitting portion 92 is determined by the height of the holding plate 94. In this embodiment, the lower end region of the first buried panel 10(A) is fitted into one panel fitting portion 92 (retaining groove 93) of the auxiliary member 9, and the lower end region of the second buried panel 10(B) is fitted into the other panel fitting portion 92 (retaining groove 93), thereby allowing these panels to be held in a self-supporting manner. The height H (see FIG. 19 ) and groove width W of the retaining groove 93 in the panel fitting portion 92 are preferably adjusted so that the buried panels 10(A) and 10(C) can be easily fitted into the retaining groove 93 and that the retaining posture of each buried panel 10(A) and 10(C) when fitted into the retaining groove 93 is approximately perpendicular to the base plate 91 (so that the retaining posture is not excessively tilted). The material constituting the auxiliary member 9 is not particularly limited, but examples include metal materials such as stainless steel.

In addition, the panel fitting portion 92 of the auxiliary member 9 may be formed by machining a groove into the surface of the base plate 91, instead of forming the holding groove 93 by the gap between a pair of holding plates 94 protruding from the base plate 91 as in the above configuration.

The dashed-dotted lines in Figure 19 indicate the connection relationships between the components included in the formwork unit X'. As shown in Figure 19, when connecting the first buried panel 10(A) and the second buried panel 10(B) using the connecting member 20A, the lower through-hole 13A(1) of the first buried panel 10(A) is used. That is, the buried panel back-contact end surface 31 of the first fastener 30, which is threaded onto the male thread portion 22 provided at one end of the separator portion 21 of the connecting member 20A, is abutted against the surface (back surface) 11 of the first buried panel 10(A) around the lower through-hole 13A(1). Then, the male thread portion 42 of the flanged second fastener 43, which is inserted through the lower through-hole 13A(1) from the surface (outer surface) 12, is threaded into the female thread portion 33 of the first fastener 30. Additionally, the end surface 31 of the first fastener 30 for contacting the back surface of the buried panel, which is threaded onto the male thread 22 provided on the other end of the separator portion 21 of the connecting member 20A, is brought into contact with the surface (back surface) 11 around the through hole 13B of the second buried panel 10(B). Then, the male thread 42 of the flanged second fastener 43 inserted into the through hole 13B from the surface (outer surface) 12 of the second buried panel 10(B) is threaded into the female thread 33 of the first fastener 30. This allows the first buried panel 10(A) and the second buried panel 10(B) to be connected.

On the other hand, when connecting the first buried panel 10(A) and the third buried panel 10(C) using the connecting member 20B, the upper end through-hole 13A(2) of the first buried panel 10(A) is used. That is, the buried panel back surface abutting end face 31 of the first fastener 30, which is threaded onto the male thread portion 22 provided at one end of the separator portion 21 of the connecting member 20B, is abutted against the surface (back surface) 11 around the upper through-hole 13A(2) of the first buried panel 10(A). Then, the male thread portion 42 of the flanged second fastener 43, which is inserted into the upper through-hole 13A(2) from the surface (outer surface) 12 of the first buried panel 10(A), is threaded into the female thread portion 33 of the first fastener 30. Additionally, the embedded panel backside abutting end surface 31 of the first fastener 30, which is threaded onto the male thread 22 provided on the other end of the separator portion 21 of the connecting member 20B, is brought into contact with the surface (back surface) 11 around the through hole 13C of the third embedded panel 10(C). Then, the male thread 42 of the flanged second fastener 43, inserted into the through hole 13C from the surface (outer surface) 12 of the third embedded panel 10(C), is threaded into the female thread 33 of the first fastener 30. This allows the first embedded panel 10(A) and the third embedded panel 10(C) to be connected.

In addition, in this embodiment, the lower end regions of the first buried panel 10 (A) and the second buried panel 10 (B) described above are fitted into and held in a pair of panel fitting portions 92 (retaining grooves 93) on the auxiliary member 9.

The height dimension from the lower end 15A of the first buried panel 10(A) to the center of the lower through-hole 13A(1) is equal to the height dimension from the lower end 15B of the second buried panel 10(B) to the center of the through-hole 13B. This makes it easy to align the heights of the lower ends 15A, 15B of the first buried panel 10(A) and the second buried panel 10(B) when assembling the formwork unit X' to install the prefabricated formwork unit Y'. Furthermore, the height dimension from the upper end 16A of the first buried panel 10(A) to the center of the upper through-hole 13A(2) is equal to the height dimension from the upper end 16C of the third buried panel 10(C) to the center of the through-hole 13B. This makes it easy to align the heights of the upper ends 16A, 16C of the first buried panel 10(A) and the third buried panel 10(C) when assembling the formwork unit X' to install the prefabricated formwork unit Y'.

Next, we will explain the method for constructing a concrete structure using the prefabricated formwork unit Y'. The concrete structure construction method first involves placing slab reinforcement ST in the first slab construction area A1 and the second slab construction area A2 (slab reinforcement process). That is, the slab reinforcement ST is assembled on a base 101, such as a half-precast deck slab (see Figures 16, 17, etc.).

Next, the formwork unit X' described in Figures 19 to 23 is assembled, and the resulting prefabricated formwork unit Y' is installed in the specified position as shown in Figures 16 and 17 (unit installation process). Specifically, the lower regions of the first buried panel 10(A) and the second buried panel 10(B) are connected using connecting member 20A, first fastener 30, and second fastener with flange 43, and the upper region of the first buried panel 10(A) and the third buried panel 10(C) are connected using connecting member 20B, first fastener 30, and second fastener with flange 43. At this time, the first buried panel 10(A) and the second buried panel 10(B) are connected with their respective surfaces (back surfaces) 11 facing each other. The first buried panel 10(A) and the third buried panel 10(C) are also connected with their respective surfaces (back surfaces) 11 facing each other.

In the unit installation process, the first buried panel 10(A) and the second buried panel 10(B) are assembled with their respective lower end regions fitted into a pair of panel fitting portions 92 (retaining grooves 93) on the auxiliary member 9. The auxiliary member 9 may be fixed so that the first buried panel 10(A) and the second buried panel 10(B), held in the panel fitting portions 92 (retaining grooves 93), are positioned in a specified position. In the example shown in Figure 17, the base plate 91 of the auxiliary member 9 is positioned and fixed relative to the slab reinforcement ST via a rod-shaped member or the like. In this case, the auxiliary member 9 can be fixed in a specified position and orientation by, for example, welding one end of a reinforcing bar indicated by the symbol 94 to the base plate 91 and welding the other end of the reinforcing bar 94 to a non-movable part (immovable part) such as the slab reinforcement ST. By fixing the auxiliary member 9 in a horizontal position, the bottom ends of the first embedded panel 10(A) and the second embedded panel 10(B) can be easily fixed with their heights aligned.

Furthermore, when installing the prefabricated formwork unit Y', as shown in Figure 17, the separator portion 21 of the connecting member 20A may be positioned and fixed to a non-movable portion (immovable portion) such as the slab reinforcement ST via a rod-shaped member 95. Similarly, the separator portion 21 of the connecting member 20B may be positioned and fixed to a non-movable portion (immovable portion) such as the slab reinforcement ST via a rod-shaped member 95. Furthermore, the auxiliary member 9 is an optional member and does not necessarily have to be provided. There are no particular restrictions on the specific means as long as the prefabricated formwork unit Y' can be positioned and fixed to the immovable portion (immovable portion). Note that when the rising step 110 is made of reinforced concrete, the prefabricated formwork unit Y
Reinforcement is then arranged within the concrete filling section 80' defined by each of the embedded panels 10(A) to (C) of the prefabricated formwork unit Y'. The reinforcement in the concrete filling section 80' may be arranged either before or after the prefabricated formwork unit Y' is installed.

Once the installation of the prefabricated formwork unit Y' is completed as described above, the concrete raw materials are poured into the construction location of the concrete structure (concrete pouring process). Figure 24 is a diagram illustrating the steps of the concrete pouring process according to embodiment 2.

First, as shown in the slab concrete pouring process in Figure 24(a), concrete raw material (fresh concrete) Cr1 is poured into the first slab construction area A1 and the second slab construction area A2. During this process, the concrete raw material Cr1 is filled into the first slab construction area A1 up to the first top surface height L1, and into the second slab construction area A2 up to the second top surface height L2. As described above, the lower ends of the first embedded panel 10(A) and the second embedded panel 10(B) in the prefabricated formwork unit Y' are positioned lower than the first top surface height L1 and the second top surface height L2. Therefore, at the completion of the slab concrete pouring process shown in Figure 24(a), the lower end regions of each embedded panel 10(A), 10(B) are buried in the concrete raw material Cr1.

Next, concrete raw material (fresh concrete) is filled inside the concrete filling section 80'. Specifically, as shown in FIG. 24(b), concrete raw material Cr2 is first filled into the concrete filling section 80' up to the third upper surface height L3 (first rising concrete pouring process). As shown in FIG. 17, the upper part of the concrete filling section 80' is open in the prefabricated formwork unit Y'. Therefore, in the first rising concrete pouring process, concrete raw material Cr2 may be poured into the concrete filling section 80' through the upper opening formed between the second embedded panel 10(B) and the third embedded panel 10(C), for example. Here, the first rising concrete pouring process may be performed before the concrete raw material Cr1 poured in the previous process hardens, i.e., continuously after the pouring of concrete raw material Cr1.

As described above, when the concrete raw material Cr2 is filled inside the concrete-filled section 80' up to the third upper surface height L3, the lower end regions of each embedded panel 10(A), 10(B) are embedded in the concrete raw material Cr1. Therefore, when the concrete raw material Cr2 is raised to the third upper surface height L3 in the first concrete pouring step, leakage (extrusion) of the concrete raw material Cr2 from the concrete-filled section 80' into the first slab construction area A1, the second slab construction area A2, and the first filling area R11 is prevented. As a result, the formation of an excessively inclined portion compared to the intended recessed corner shape formed by the first side surface 113 (the outer surface of the first embedded panel 10(A)) of the first step portion 120 (the sash frame rising portion) in the rising step 110 and the indoor slab upper surface SH1 is effectively prevented. Similarly, the formation of an excessively inclined portion compared to the intended recessed corner shape formed by the second side surface 114 (the outer surface of the second embedded panel 10(B)) of the second step portion 130 (the rising portion for returning water to the balcony) in the rising step 110 and the balcony-side slab upper surface SH2 can be effectively prevented. Furthermore, as described above, because there is no leakage of concrete raw material Cr2, there is no need to scrape off the resulting excess (chipping work) or perform subsequent repair work as needed, reducing the work, time, and cost required for construction.

After the first concrete pouring step is completed as described above, the concrete filling section 80' is filled with the concrete raw material Cr3 up to the fourth upper surface height L4 (second concrete pouring step) as shown in FIG. 24(c). For example, the concrete raw material Cr3 may be poured into the concrete filling section 80' through an upper opening formed between the first embedded panel 10(A) and the third embedded panel 10(C). In this case, the concrete raw material Cr3 may be poured continuously, for example, following the pouring of the concrete raw material Cr2, before the concrete raw material Cr3 poured in the previous step hardens.

Here, the area of the concrete-filled section 80' that is filled with the concrete raw material Cr3 during the second concrete pouring step is specifically referred to as the "sash frame concrete-filled section 80A." During the second concrete pouring step, the concrete raw material Cr3 is filled into the sash frame concrete-filled section 80A while the lower end region of the third embedded panel 10(C) is buried in the concrete raw material Cr2. This prevents the concrete raw material Cr3 from leaking (overflowing) from the sash frame concrete-filled section 80A onto the balcony step upper surface 112 when filling the sash frame concrete-filled section 80A with the concrete raw material Cr3 up to the fourth upper surface height L4. As a result, it is possible to effectively prevent the formation of an excessively inclined portion compared to the intended recessed corner shape formed by the third side surface 115 (the outer surface of the third embedded panel 10(C)) of the second step portion 130 (the rising portion for returning water to the balcony) in the rising step 110 and the balcony step upper surface 112. Furthermore, this also eliminates the need to scrape away excess concrete (chipping work) or perform subsequent repair work as needed, thereby reducing the work, time, and cost required for construction.

Through the above process, slabs (indoor slab S1 and balcony slab S2) with concrete steps 110 protruding from their upper surfaces can be constructed in one step by pouring concrete. This not only reduces the construction man-hours (number of days) required for the above concrete structures, but also makes it possible to construct concrete structures that are highly waterproof, strong, and durable by integrating the concrete structures.

Of course, during each of the concrete pouring processes described above, compaction can be performed as needed to pack the supplied concrete raw materials tightly, and the concrete surfaces in various locations (such as the indoor slab top surface SH1, the balcony slab top surface SH2, the sash frame top surface 111, and the balcony step top surface 112) can be finished. Of course, when finishing the concrete surfaces of the balcony slab top surface SH2 and the balcony step top surface 112, a water gradient can be added to allow for drainage of rainwater and other water. This can prevent rainwater and other water from accumulating on the balcony slab top surface SH2 and the balcony step top surface 112.

Furthermore, as shown in Figure 17, since the lower region of the third embedded panel (C) is buried in the concrete raw material Cr2, an adhesion-improving surface may be provided not only on the surface (rear surface) 11 side of the lower region, but also on the surface (outer surface) 12 side.

In addition, in this embodiment, the first side 113, second side 114, and third side 115 of the rising step 110 are all formed by the buried panels 10(A) to 10(C). This eliminates the need to remove the panels after pouring the concrete, as was previously required, reducing the work, time, and cost required for construction. The flanged second fasteners 43 used to secure the buried panels 10(A) to 10(C) may be left in place after pouring the concrete, or may be removed after a specified curing period. The female threads 33 of the first fasteners 30 and the through holes in the buried panels, which are exposed when the flanged second fasteners 43 are removed from the first fasteners 30, may be filled with mortar or the like.

As described above, the formwork unit X' in this embodiment is used to construct slabs (indoor side slab S1 and balcony side slab S2) on the upper surface of which the concrete raised step 110 is protruding, and includes a plurality of embedded panels 10(A) to 10(C), a plurality of connecting members 20A that interconnect the embedded panels 10(A) and 10(B), and a plurality of embedded panels 10(C).
The device comprises a plurality of connecting members 20B interconnecting (A) and (C), a plurality of first fasteners 30, and a plurality of second fasteners 43 with flanges, and each connecting member 20A, 20B has a separator portion 21 and a male thread portion 22 provided on both ends of the separator portion 21.

In the formwork unit X' according to embodiment 2, as in the above-described embodiments, for each of the buried panels 10(A) to 10(C), the sum of the contact area of the flange-shaped head 44 of the flanged second fastener 43 with the buried panel surface (when a combination of the second fastener 40 and flange 23 is used instead of the flanged second fastener 43, the contact area of the flange 23 with the buried panel surface) and the contact area of the first fastener 30 with the buried panel back surface is set to 2% or more of one surface area of the buried panel. This provides excellent reinforcement for the connection between each buried panel 10(A) to 10(C) and each connecting member 20A, 20B, and allows the buried panels 10(A) to 10(C) to withstand higher lateral pressure during concrete pouring.

The prefabricated formwork unit Y′ according to the second embodiment is as follows:
a first embedded panel 10(A) that is installed on the side of the first slab construction planned area A1 where the indoor side slab (first slab area) S1 will be constructed and that forms a first side surface 113 of a first step portion 120 that rises from the upper surface SH1 of the indoor side slab S1;
a second embedded panel 10(B) that is installed on the second slab construction planned area A2 side where the balcony side slab (second slab area) S2 will be constructed and that forms the second side surface 114 of the second step portion 130 that rises from the upper surface SH2 of the balcony side slab S2;
a third embedded panel 10(C) that is set between the first embedded panel 10(A) and the second embedded panel 10(B) and that forms a third side surface 115 that rises from the upper surface 112 of the second step portion 130;
a connecting member 20A, a first fixing member 30, and a second fixing member 43 (second fixing member 40) that connect the back surfaces 11 of the first embedded panel 10 (A) and the second embedded panel 10 (B) in a state where they are arranged opposite each other;
a connecting member 20B, a first fixing device 30, and a second fixing device 43 (second fixing device 40) that connect the back surfaces 11 of the first embedded panel 10 (A) and the third embedded panel 10 (C) in a state where they are arranged opposite each other;
The lower end 15A of the first embedded panel 10(A) is disposed at a position equal to or lower than the first upper surface height L1 corresponding to the upper surface SH1 of the indoor side slab S1,
The lower end 15B of the second embedded panel 10(B) is disposed at a position equal to or lower than the second upper surface height L2 corresponding to the upper surface SH2 of the balcony side slab S2,
The lower end 15C of the third embedded panel 10(C) is positioned at a position equal to or lower than the third upper surface height L3 corresponding to the upper surface 112 of the second step portion 130.
The prefabricated formwork unit Y' reduces the number of construction days required for a concrete structure by unitizing multiple embedded panels. Furthermore, by pouring concrete into the concrete-filled compartments 80' formed on the back surfaces 11 of the first embedded panel 10(A) through the third embedded panel 10(C) when pouring concrete into the first slab construction area A1 and the second slab construction area A2, the raised step 110 as a composite step structure including the sash frame raised portion 120 and the balcony water return raised portion (second step portion 130) can be constructed simultaneously with the slabs S1 and S2 (by pouring concrete in a single operation). This allows each part to be constructed at once without forming joints in the concrete that makes up the slabs (indoor slab S1, balcony side slab S2), first step portion 120 (rising portion for sash frame), and second step portion 130 (rising portion for balcony water return), thereby making it possible to construct a concrete structure that is excellent in waterproofness, strength, and durability.

Example 5
Example 5 (an example corresponding to Embodiment 2) will be described below. In Example 5, when pouring a slab, as described in the above-mentioned Embodiment 2, a prefabricated formwork unit Y' assembled from the following formwork units X' was installed at the boundary between the first slab construction planned area A1 where the indoor side slab S1 was to be constructed and the second slab construction planned area A2 where the balcony side slab S2 was to be constructed, and the prefabricated formwork unit Y' was used to construct a rising step 110 as a composite step structure including a rising portion for a sash frame and a rising portion for a balcony water return, simultaneously with the above-mentioned slabs S1 and S2.

The following formwork units X' were used:
Buried panel: "Cell Slim Step Board" manufactured by Daicel FineChem Co., Ltd. (longitudinal dimension × thickness dimension = 1820 mm × 6.5 mm) was used.
The height dimensions (short dimension perpendicular to the longitudinal and thickness directions) of the first embedded panel 10 (A) positioned on the side of the first slab construction area A1 at the boundary between the concrete filled area 80' defined inside the prefabricated formwork unit Y' and the first slab construction area A1, the second embedded panel 10 (B) positioned on the side of the second slab construction area A2 at the boundary between the concrete filled area 80' and the second slab construction area A2, and the third embedded panel 10 (C) positioned between the first embedded panel 10 (A) and the second embedded panel 10 (B) were 170 mm, 130 mm, and 70 mm, respectively.

The through holes of the first buried panel 10 (A) are arranged in a row of five upper and lower through holes spaced apart along the width direction (longitudinal direction) of the panel, as shown in Figure 20, and the upper and lower through holes are arranged in a line in the vertical direction.
As shown in FIG. 21, five through holes in the second buried panel 10(B) were arranged in a horizontal row at intervals along the width direction (longitudinal direction) of the panel.
As shown in FIG. 22, five through holes in the second buried panel 10(B) were arranged in a horizontal row along the width direction (longitudinal direction) of the panel at intervals.

First fixing tool: KP Kondannetsu Pad (area of end face for contacting the back surface of buried panel: 19.6 cm ² /piece) manufactured by Sankyo Tech Co., Ltd. was used.
Second fixing tool with flange: Slim head screw with flange (area of end face for contacting the buried panel surface: 1.3 cm ² /piece) was used.
Connecting member: A separator portion having external threads on both ends was used.
Auxiliary member: A rectangular thin stainless steel plate about 1.1 mm thick with holding grooves each having a height H of about 7 mm and a groove width W of about 7 mm formed on both ends was used as the base plate.

The first buried panel 10(A) and the second buried panel 10(B) were assembled parallel to each other with their back surfaces facing each other using the first fastener, the second fastener with a flange, and the second fastener with a flange. The first buried panel 10(A) and the second buried panel 10(B) were assembled using the lower through-hole of the first buried panel 10(A). The lower ends of the first buried panel 10(A) and the second buried panel 10(B) were aligned in height and separated by 300 mm. The lower ends of the first buried panel 10(A) and the second buried panel 10(B) were attached to the auxiliary member by fitting them into the retaining grooves of the auxiliary member. Four auxiliary members were prepared and attached to the bottom ends of the first embedded panel 10(A) and the second embedded panel 10(B) at intervals along the panel width (longitudinal) direction.

The first buried panel 10(A) and the third buried panel 10(C) were assembled parallel to each other with their back surfaces facing each other using the first fastener, the second fastener with a flange, and the second fastener with a flange. The first buried panel 10(A) and the third buried panel 10(C) were assembled using the upper end through-hole of the first buried panel 10(A), with the upper ends of the first buried panel 10(A) and the third buried panel 10(C) aligned in height and separated by a distance of 100 mm.

As described above, prefabricated formwork unit Y', assembled with first embedded panel 10(A) through third embedded panel 10(C), was installed at the boundary between the planned first slab construction area, where the indoor slab would be constructed, and the planned second slab construction area, where the balcony side slab would be constructed, i.e., at the location where a riser step would be constructed, including a sash frame rising section, which would serve as a stand for attaching the sash frames, and a balcony water return rising section. Prefabricated formwork unit Y' was fixed in place by welding the separator sections of some of the connecting members used to connect each embedded panel, and the base plates of some of the auxiliary members, to the slab reinforcement. In this case, the sum of the contact area of the flange portion (flange-shaped head) of the flanged second fastener with each buried panel 10(A) to 10(C) and the contact area of the end face of the first fastener for contacting the back surface of the buried panel was approximately 7% of one surface area of the first buried panel 10(A), approximately 4% of one surface area of the second buried panel 10(B), and approximately 8% of one surface area of the third buried panel 10(C).

The rising steps, including the rising sections for the sash frames and the rising sections for the balcony water return, the indoor slab, and the balcony side slab were constructed in a single concrete pour. As a result, there was no need for chipping or repair work due to concrete overflowing from the prefabricated formwork unit Y'. Furthermore, the shape and dimensions of the space formed by the prefabricated formwork unit Y' were as designed.

X Formwork unit Y Assembled formwork unit 10 Buried panel 11 Buried panel back side 12 Buried panel front side 13 Buried panel hole (or through hole)
14 Anchor bolt 20 Connecting member 21 Separator portion 22 Male thread portion 23 Flange 23A End surface of flange for contacting the surface of embedded panel 24 Flange hole 30 First fixing device 31 End surface for contacting the back surface of embedded panel 32 Convex body 33 Female thread portion of first fixing device 34 Base portion 40 Second fixing device 41 Head 42 Male thread portion 43 Second fixing device with flange 44 Flange-shaped head 50A, 50B Connecting device 51, 53 Flat plate 52, 54 Fastening material 60A, 60B Height adjustment device 61, 64 Receiving member 62, 65 Leg member 63, 66 Connecting metal fitting 70 Beam 71 Ceiling 72 Window frame 73 Surface to be repaired of concrete structure 74 Ground 75 Wall 76 Tread or floor surface of rising step 77 Upper surface of rising step 80 Concrete (raw material) filling section 81 Steel frame or reinforcing bar

Claims (1)

A method for constructing a concrete structure, comprising: pouring concrete using a formwork unit when pouring concrete to construct a slab including a first slab region and a second slab region; and constructing a composite step structure including a first step portion and a second step portion having different top surface heights in a convex shape on an upper surface of the slab;
The formwork unit comprises:
a first embedded panel for forming a first side surface of the first step portion rising from the upper surface of the first slab region;
a second embedded panel for forming a second side surface of the second step portion rising from the upper surface of the second slab region;
a third embedded panel for forming a third side surface rising from an upper surface of the second step portion;
Equipped with
The method comprises:
a unit installation process for assembling the formwork unit and installing it at the boundary between a first slab construction area where the first slab area is to be constructed and a second slab construction area where the second slab area is to be constructed ;
a concrete pouring process for pouring concrete raw materials into a construction location of a concrete structure;
Equipped with
In the unit installation step,
The first buried panel is installed on the side of the area where the first slab is to be constructed, the second buried panel is installed on the side of the area where the second slab is to be constructed, and the third buried panel is installed between the first buried panel and the second buried panel, and the first buried panel and the second buried panel, and the first buried panel and the third buried panel are connected with their back surfaces facing each other,
and,
The lower end of the first embedded panel is positioned at a position lower than a first upper surface height corresponding to the upper surface of the first slab region;
The lower end of the second embedded panel is positioned at a position lower than a second upper surface height corresponding to the upper surface of the second slab region;
The lower end of the third embedded panel is disposed at a position lower than a third upper surface height corresponding to the upper surface of the second step portion,
The concrete pouring step includes:
a slab concrete pouring step of pouring concrete raw materials into the first slab construction planned area and the second slab construction planned area;
Following the slab concrete pouring step, a first rising concrete pouring step is performed in which concrete raw material is poured from an upper opening formed between the second embedded panel and the third embedded panel.
Following the first concrete pouring step, a second concrete pouring step is performed to pour concrete raw materials through an upper opening formed between the first embedded panel and the third embedded panel.
Including,
In the slab concrete pouring step, concrete raw material is poured into the first slab construction planned area up to the first upper surface height, and concrete raw material is poured into the second slab construction planned area up to the second upper surface height, so that lower end regions of the first embedded panel and the second embedded panel are buried in the concrete raw material;
Before the concrete poured in the slab concrete pouring step hardens, in the rising first concrete pouring step, concrete raw material is poured up to a third upper surface height so that a lower end region of the third embedded panel is buried in the concrete raw material,
Before the concrete poured in the first concrete pouring step hardens, in the second concrete pouring step, the concrete raw material is poured up to the fourth upper surface height from a state in which the lower end region of the third embedded panel is buried in the concrete raw material,
The slab and the composite step structure are constructed together;
Concrete structure construction methods.