How to construct a structure
By fixing formwork to reinforcing materials and using concrete as a core material, the method addresses labor shortages and mortar loss issues, improving workability and adhesion in concrete structure construction.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- KAJIMA CORP
- Filing Date
- 2022-08-01
- Publication Date
- 2026-05-12
AI Technical Summary
Existing construction methods for concrete structures face complications due to the need for multiple trades, labor shortages, and issues with lath mesh causing mortar loss and adhesion problems when used as a core material.
A method involving fixing formwork to reinforcing materials, pouring concrete inside, and applying a cement-based hardening agent to form the outer shell, utilizing the concrete as a core material and embedding shear reinforcement bars to support lateral pressure.
Improves workability by eliminating mortar loss, ensuring adhesion performance, and simplifying construction by reducing the need for separate formwork members and labor, while enhancing the adhesion and aesthetic appearance of the finished product.
Smart Images
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Abstract
Description
Technical Field
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[0001] The present invention relates to a method for constructing a structure and the like.
Background Art
[0002] When constructing a concrete structure such as a wall, it has been common to assemble reinforcing bars, assemble a formwork, place concrete, and demold after curing to a predetermined age.
[0003] Thus, when constructing a concrete structure, multiple trades are mixed, and the work is complicated. In recent years, there has been a tendency for a shortage of construction skilled workers, especially a significant decrease in the number of carpenters, and it is expected that it will become difficult to secure carpenters in the future.
[0004] Therefore, in recent years, the development of a simpler construction method has been demanded. As an example, in Patent Document 1, after forming the outer shell portion of a structure by a spraying method of a cement-based material such as mortar, concrete is placed inside using the outer shell portion as a formwork, thereby constructing the structure. This can simplify the construction of the structure by replacing the conventional wooden formwork with the sprayed outer shell portion and can cope with the shortage of workers.
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0006] Patent Document 1 also describes the use of lath mesh as a core material when spraying mortar, etc. This method is highly versatile because it facilitates the installation of the core material and improves the adhesion of the mortar, etc. However, when using lath mesh as a core material, the mortar, etc. can pass through the mesh during spraying, resulting in loss of mortar, etc. and reducing workability.
[0007] Furthermore, the spraying pressure can cause the lath mesh to bulge inward, potentially leading to problems with the finished product and loss of mortar and other materials due to this deformation. In addition, if the interior of the structure is made of reinforced concrete, mortar and other materials that pass through the lath mesh may adhere to the reinforcing steel located inside the lath mesh, raising concerns about a decrease in the adhesion performance between the reinforcing steel and the concrete.
[0008] This invention has been made in view of the above-mentioned problems, and aims to provide a method for constructing a structure that can improve workability. [Means for solving the problem]
[0009] The present invention, which solves the aforementioned problems, is a method for constructing a structure, comprising the steps of: (a) fixing a formwork to a reinforcing material embedded in the structure and filling the inside of the formwork with concrete to form the interior of the structure; and (b) applying a hardening agent made of cement-based material to the outer surface of the interior of the structure to form the outer shell of the structure, thereby constructing the structure, and on the outside of the formwork, the outer shell This is a method for constructing a structure characterized by the placement of reinforcing bars embedded in the section.
[0010] In this invention, the concrete inside the structure, which is poured in advance, serves as the core material when cement-based materials such as mortar are applied to form the outer shell. This eliminates waste due to the mortar passing through, thereby improving workability. The formwork is fixed to the reinforcing material of the structure, eliminating the need for separate members to fix the formwork, thus reducing labor during construction.
[0011] Furthermore, because the concrete inside the structure is poured first, even if the reinforcing material is located inside the formwork, the adhesion performance between the reinforcing material and the concrete can be naturally ensured. In addition, there is no risk of deformation of the core material due to spraying pressure, etc., and there is no concern that problems with the finished product may arise.
[0012] The formwork is made of lath mesh, and it is desirable that the lath mesh be left on the outer surface inside the structure. This improves the adhesion of hardening materials such as mortar when applying them to the outer surface of the interior of a structure.
[0013] It is desirable that shear reinforcement bars are embedded inside the structure so that the lateral pressure during concrete filling is supported by the shear reinforcement bars. In this invention, by utilizing the shear reinforcement bars of the structure as separators, the installation of separators in conventional formwork can be omitted, simplifying construction. However, in some cases, the rigidity of the main reinforcement bars and distribution bars alone may be sufficient to resist lateral pressure.
[0014] The formwork is a reinforcing material for the structure and the outer shell It is desirable that the reinforcement bars embedded in the section be fixed to the inside of the main reinforcement and distribution reinforcement. This allows the formwork to be fixed to the reinforcing material in a simple manner.
[0015] Furthermore, it is desirable that the formwork be fixed using a fixing jig. This allows the formwork to be easily and securely fixed to the reinforcing material.
[0016] It is desirable that shear reinforcement bars are embedded inside the structure, and that the fixing jig used is an anchoring jig for the end of the shear reinforcement bars. In this invention, the formwork can be efficiently fixed using a shear reinforcement fixing jig, which leads to a reduction in construction time and materials. [Effects of the Invention]
[0017] The present invention provides a method for constructing a structure that can improve workability.
Brief Description of the Drawings
[0018] [Figure 1] A diagram showing the construction method of the structure 1. [Figure 2] A diagram showing the lath net 3. [Figure 3] A diagram showing the fixing jig 5. [Figure 4] An example of fixing the lath net 3 inside the main reinforcement bars 21 and the distribution reinforcement bars 22. [Figure 5] A diagram showing the fixing jig 5a. [Figure 6] A diagram showing the reinforcing bar 4. [Figure 7] A diagram showing the mesh bar 6 and the net 7. [Figure 8] An example of using the thin-diameter reinforcing bar 8. [Figure 9] An example of using the sheet material 9. [Figure 10] An example of using the separator 10.
Modes for Carrying Out the Invention
[0019] Hereinafter, preferred embodiments of the present invention will be described in detail based on the drawings.
[0020] FIG. 1 is a cross-sectional view showing each step of the construction method of the structure 1 according to an embodiment of the present invention. In this embodiment, a wall-shaped structure 1 is constructed, and each view in FIG. 1 shows a vertical cross-section in the thickness direction of the structure 1. The thickness direction of the structure 1 corresponds to the left-right direction in each view.
[0021] In this embodiment, as shown in FIG. 1(a), first, the reinforcing bars 2, which are the reinforcing materials embedded in the structure 1, are assembled. In this embodiment, as the reinforcing bars 2 of the structure 1, main reinforcement bars 21, distribution reinforcement bars 22, and shear reinforcement bars 23 are arranged.
[0022] The main reinforcement bars 21 are vertical reinforcement bars, and multiple bars are arranged at intervals on both sides of the thickness direction of the structure 1, in the extension direction in the plane of the structure 1 (hereinafter simply referred to as the extension direction). The extension direction of the structure 1 is perpendicular to the thickness direction of the structure 1 in the plane, and corresponds to the plane normal direction in Figure 1.
[0023] The distribution reinforcement bars 22 are horizontal reinforcement bars, and are arranged on both sides of the thickness direction of the structure 1, along the extension direction of the structure 1. The distribution reinforcement bars 22 are arranged in multiple vertical layers with spacing between them.
[0024] The shear reinforcement bars 23 are horizontal reinforcement bars and are arranged along the thickness direction of the structure 1. The shear reinforcement bars 23 are arranged in multiple vertical rows with spacing between them, and these multiple vertical rows of shear reinforcement bars 23 are arranged in multiple rows with spacing between them in the extension direction of the structure 1.
[0025] In this embodiment, after the reinforcing bars 2 are placed, the lath mesh 3 is fixed to the reinforcing bars 2 on both sides in the thickness direction of the structure 1, as shown in Figure 1(b). The lath mesh 3 functions as formwork when the concrete C is filled, as will be described later.
[0026] The lath mesh 3 is a mesh-like member with numerous openings (mesh holes). For the lath mesh 3, for example, steel blind metal can be used. Figure 2(a) shows an elevation view of the blind metal, in which hexagonal openings 31 are arranged vertically and horizontally. Also, as shown in Figure 2(b), by orienting the openings 31 of the blind metal upwards, leakage of concrete C during filling can be suppressed.
[0027] The lath mesh 3 can be secured to the outside of the main reinforcement bars 21 or distribution reinforcement bars 22 by tying it with binding wire or the like. Alternatively, as shown in Figure 3, it is also possible to secure the lath mesh 3 to the outside of the main reinforcement bars 21 or distribution reinforcement bars 22 (distribution reinforcement bars 22 in the example of Figure 3) using a fixing jig 5, which allows for easy and reliable securing of the lath mesh 3. Note that "outside" refers to the external side of the structure 1, and the internal side of the structure 1 is referred to as "inside".
[0028] The fixing jig 5 in Figure 3 has a configuration in which a male screw 52 is screwed into a female screw hole provided on the wall surface of a C-shaped clamp 51. The tip of the male screw 52 is pressed against the reinforcing bar 22 inserted inside the clamp 51 to attach it to the reinforcing bar 22. The male screw 52 passes through the lath mesh 3, and a nut 53 is screwed onto it from the outside. The lath mesh 3 is sandwiched between the nut 53 and the clamp 51, thereby fixing the lath mesh 3 to the reinforcing bar 22. It is also possible to fix the lath mesh 3 to the main reinforcing bar 21 in a similar manner. This is also the case in other examples described later, and in examples where the target of fixing is the reinforcing bar 22, it is also possible to fix it to the main reinforcing bar 21 in a similar manner.
[0029] After fixing the lath mesh 3 in this manner, concrete C is poured and filled inside the lath mesh 3, as shown in Figure 1(c). The interior of the structure 1 is formed as the concrete C hardens. The lateral pressure applied to the lath mesh 3 during the filling of concrete C is supported by the shear reinforcement bars 23 via the main reinforcement bars 21 or distribution bars 22 that fix the lath mesh 3.
[0030] After forming the interior of the structure 1 in this way, the hardening agent H is sprayed and applied to the outer surface of the interior of the structure 1, as shown in Figure 1(d). In this embodiment, the lath mesh 3 is left on the outer surface, and irregularities are formed on the outer surface as illustrated in Figure 2(b), thereby improving the adhesion of the hardening agent H.
[0031] The hardening agent H is a cement-based material such as mortar or concrete, and it provides cover over the reinforcing bars 2. For example, using high-strength mortar as the hardening agent H can increase the durability of the structure 1. Alternatively, ultra-high-strength fiber-reinforced concrete can be used as the hardening agent H, and the bending toughness due to the inclusion of high-tensile-strength steel fibers can reduce the amount of reinforcing bars 2 in the structure 1.
[0032] The hardening agent H can be sprayed using a spraying machine on the outside of the lath mesh 3. After spraying, the surface of the hardening agent H can be smoothed by, for example, manual trowel finishing to improve the aesthetic appearance of the structure 1.
[0033] After this, curing is performed to harden the hardening agent H, thereby forming the outer shell of structure 1. By forming the interior and outer shell of structure 1 in this way, structure 1 is constructed. It is also possible to add known hardening accelerators to the hardening agent H to speed up the hardening process.
[0034] As explained above, in this embodiment, the concrete C inside the structure 1, which has been poured in advance, serves as the core material when a hardening agent H such as mortar is applied to form the outer shell. This eliminates the loss caused by the mortar passing through as described above, and improves the constructability of the structure 1. By fixing the lath mesh 3 to the reinforcing bars 2 of the structure 1, there is no need to provide separate members for fixing the formwork, thus saving labor during construction.
[0035] Furthermore, since the concrete C inside structure 1 is poured first, the adhesion performance between the reinforcing bars 2 and concrete C is naturally ensured, and there is no concern about impairing the structural performance of structure 1. In addition, there is no risk of deformation of the core material due to spraying pressure, and there is no concern about problems with the finished product.
[0036] Furthermore, in this embodiment, most of the formwork during concrete C filling can be replaced by the installation of lightweight and easily deformable lath mesh 3, simplifying construction and eliminating the need for demolding. Additionally, by applying the hardening agent H to the outer surface of the concrete C with the lath mesh 3 remaining, the adhesion of the hardening agent H is improved due to the uneven surface, and the application of the hardening agent H also improves the aesthetic appearance.
[0037] Furthermore, in this embodiment, the shear reinforcement bars 23 of the structure 1 are used to resist lateral pressure during the filling of concrete C, and by utilizing the shear reinforcement bars 23 as separators, the installation of separators in conventional formwork can be omitted, simplifying construction. However, in some cases, the rigidity of the main reinforcement bars 21 and the distribution bars 22 may be sufficient to resist lateral pressure during the filling of concrete C, in which case it is not necessary to resist lateral pressure with the shear reinforcement bars 23.
[0038] However, the present invention is not limited to the embodiments described above. For example, in this embodiment, the lath mesh 3 is fixed to the outside of the main reinforcement bars 21 and the distribution reinforcement bars 22, but as shown in Figure 4, the lath mesh 3 may be fixed to the inside of the main reinforcement bars 21 and the distribution reinforcement bars 22.
[0039] As a result, the lath mesh 3 does not peel off from the main reinforcement bars 21 and distribution bars 22 when concrete C is filled, and fixing the lath mesh 3 to the main reinforcement bars 21 and distribution bars 22 can be done by a simple method. However, the installation of the lath mesh 3 must be done in the space inside the main reinforcement bars 21 and distribution bars 22 where the shear reinforcement bars 23 are present, and it is also necessary to pass the shear reinforcement bars 23 through the lath mesh 3, so in this respect, fixing the lath mesh 3 to the outside of the main reinforcement bars 21 and distribution bars 22 is more efficient.
[0040] Furthermore, the shape and configuration of the fixing jig 5 are not particularly limited, as long as they can fix the lath mesh 3 to the reinforcing bars 2. For example, when threaded reinforcing bars are used as shear reinforcement bars 23, as shown in Figure 5(a), the permanent anchoring jig for the shear reinforcement bars 23 may be used as the fixing jig 5a for the lath mesh 3, which allows for efficient fixing of the lath mesh 3 and leads to a reduction in construction time and materials.
[0041] This fixing jig (fixing jig 5a) has a widened portion 541 for fixing at the outer end of the main body 54 through which a female screw hole passes. After arranging the main reinforcement bars 21, distribution reinforcement bars 22 and shear reinforcement bars 23 and installing the lath mesh 3, as shown in Figure 5(a), the ends of the shear reinforcement bars 23 are screwed into the female screw holes of the main body 54 through which the lath mesh 3 passes, and the widened portion 541 presses the lath mesh 3 towards the distribution reinforcement bars 22, thereby fixing the lath mesh 3 to the distribution reinforcement bars 22.
[0042] As shown in Figure 5(b), a nut 55 can also be screwed onto the tip of the shear reinforcement bar 23 that protrudes from the main body 54 and penetrates the lath mesh 3, and the lath mesh 3 can be clamped between this nut 55 and the widened portion 541 of the main body 54, thereby efficiently fixing the lath mesh 3 to the shear reinforcement bar 23. In this case, the position of the lath mesh 3 in the axial direction of the shear reinforcement bar 23 can also be adjusted by changing the position of the fixing jig 5a in the axial direction of the shear reinforcement bar 23.
[0043] Alternatively, as shown in Figure 6(a), reinforcing bars 4 may be placed on the outside of the lath mesh 3, and the distribution bars 22, lath mesh 3, and reinforcing bars 4 may be tied and fixed together with binding wire W. By providing reinforcing bars 4 on the outside of the lath mesh 3, the lath mesh 3 can be reinforced against lateral pressure when the concrete C is filled.
[0044] The reinforcing bars 4 can also be used when the aforementioned fixing jigs 5 and 5a are used. In the example shown in Figure 6(b), the reinforcing bars 4 and the lath mesh 3 are held between the nut 53 (plate nut) and clamp 51 of the fixing jig 5, thereby fixing the lath mesh 3 to the load-bearing bars 22 and reinforcing the lath mesh 3 with the reinforcing bars 4. In the example shown in Figure 6(b), a similar effect can be achieved by pressing the reinforcing bars 4 and the lath mesh 3 toward the load-bearing bars 22 using the widened portion 541 of the main body 54 of the fixing jig 5a.
[0045] In this embodiment, a wire mesh 3 is used as the formwork when filling the concrete C, but instead of the wire mesh 3, a combination of mesh reinforcement 6 and net 7 may be used, as shown in Figure 7(a).
[0046] The mesh reinforcement 6 is a steel mesh member with larger openings (mesh size) than the lath mesh 3, and is formed by combining vertical and horizontal reinforcing bars 61 and 62 in a grid pattern. Because the mesh reinforcement 6 is more rigid than the lath mesh 3, it improves resistance to lateral pressure when concrete C is filled. The net 7 is a mesh member with a small mesh size formed from fibers or the like, and suppresses leakage of concrete C to the outside. The mesh reinforcement 6 and the net 7 may be pre-integrated to facilitate construction.
[0047] Alternatively, a mesh reinforcement 6 with a smaller mesh size may be used alone as a substitute for the lath mesh 3. In this case, the concrete mix and the mesh size of the mesh reinforcement 6 should be adjusted to prevent concrete C from leaking out when filling the concrete. The mesh reinforcement 6 can also be used in combination with the lath mesh 3 as a substitute for the reinforcing steel bars 4 mentioned above.
[0048] Alternatively, instead of the lath mesh 3, a continuous fiber reinforcement material such as an aramid fiber mesh sheet may be used. To ensure rigidity, it is necessary to increase the number of fixing points to the main reinforcement 21, distribution reinforcement 22, or shear reinforcement 23, but because it is lightweight, the fixing work to these reinforcements 2 becomes easier.
[0049] Furthermore, a sheet material without openings, such as vinyl or sandbag sheets, may be attached to the outside of the lath mesh 3 or mesh reinforcement 6 used as formwork when filling with concrete C, or the continuous fiber reinforcement material mentioned above. This can mitigate leakage of concrete C and strength reduction due to drying, leading to improved quality. However, in the process shown in Figure 1(c), the unevenness of the inner outer surface of the structure 1 becomes slightly smoother, and the adhesion of the hardening agent H is slightly reduced. The sheet material is removed after the concrete C has hardened.
[0050] Furthermore, instead of the lath mesh 3, as shown in Figure 8(a), small diameter reinforcing bars 8 can be welded together in a mesh pattern on-site, and the welding can be automated using a known automatic welding device to reduce labor during construction. As shown in Figure 8(b), the small diameter reinforcing bars 8 are fixed to metal fittings 24 such as gutters attached to the distribution bars 22 by welding, and this welding can also be automated using an automatic welding device. In addition, by using an automatic spraying device that automatically sprays the hardening agent H, it is possible to automate the entire process related to the formation of the outer shell.
[0051] As an alternative to the lath mesh 3, as shown in Figure 9, a resin sheet material 9 with an uneven surface can be fixed to the reinforcement bars 22 with the uneven surface facing inward, which can serve as a simple formwork when filling with concrete C. The sheet material 9 does not have openings, but it is removed before the application of the hardening agent H, and at that time, an uneven surface is formed on the outer surface of the concrete C inside the structure 1, thereby improving the adhesion of the hardening agent H.
[0052] Furthermore, the method of fixing the formwork such as the lath mesh 3 is not particularly limited. As shown in Figure 10(a), separators 10, single pipes 11, and end battens 12 may be arranged in the same way as in general formwork construction, and these may be used to fix the lath mesh 3 to the reinforcement bars 22. Although this increases labor costs and labor, it ensures reliable fixing of the lath mesh 3 and resistance to lateral pressure during concrete filling C.
[0053] In Figure 10(a), reference numerals 101 and 102 indicate a form tie (registered trademark) and a nut attached to the end of a separator 10 that penetrates the lath mesh 3, respectively. They serve to hold the single pipe 11 and end rib 12, which are positioned outside the lath mesh 3, toward the reinforcement bars 22. The separator 10 is embedded in the structure 1, but the single pipe 11, end rib 12, form tie (registered trademark) 101 and nut 102 are removed after the concrete C is filled but before the hardening agent H is applied. The end of the separator 10 can be embedded in the hardening agent H applied later, simplifying surface treatment.
[0054] As shown in Figures 10(b) and (c), the separator 10 can also be used when reinforcing bars 4 and mesh bars 6 are used, eliminating the need for single pipes 11 and saving the effort of removing them. In the example in Figure 10(b), the reinforcing bars 4 and lath mesh 3 can be pressed and fixed to the distribution bars 22 side by nuts 102 (plate nuts) screwed onto the end of the separator 10, and in the example in Figure 10(c), the mesh bars 6 and net 7 can be pressed and fixed to the distribution bars 22 side by nuts 102.
[0055] Furthermore, although the structure 1 in this embodiment is wall-shaped, the structure 1 is not limited to being wall-shaped. For example, a columnar structure 1 can also be constructed by arranging a wire mesh 3 to have a square-shaped closed cross-section, filling the inside with concrete C, and then spraying a hardening agent H.
[0056] In this embodiment, a pair of outer shells made of the hardening material H are formed at opposing positions, but in some cases, the outer shell made of the hardening material H may be formed on only one side. In that case, the opposite side of the outer shell can be various structural members, formwork and its reinforcing materials, or the ground, etc.
[0057] Furthermore, although the hardening agent H was applied by spraying in this embodiment, the method of applying the hardening agent H is not limited to spraying; it may also be applied by a plastering method. In addition, it is possible to use an automatic application device (3D printer) that automatically applies the hardening agent H based on the 3D data of the completed shape of the outer shell of the structure 1, thereby further reducing the number of workers required.
[0058] In this embodiment, reinforcing bars 2 are embedded in the structure 1 as reinforcing material for the structure 1, but in some cases, steel materials such as H-shaped steel or steel plates may be embedded as reinforcing material. In that case as well, the formwork such as wire mesh 3 can be fixed to the steel material using binding wire, fixing jigs, separators, etc.
[0059] Preferred embodiments of the present invention have been described above with reference to the attached drawings, but the present invention is not limited to these examples. It will be obvious to those skilled in the art that various modifications or alterations can be conceived within the scope of the technical idea disclosed herein, and these will naturally also fall within the technical scope of the present invention. [Explanation of Symbols]
[0060] 1: Structure 2: Reinforcement bars 3: Wire mesh 4: Reinforcing steel 5, 5a: Fixing jig 6: Mesh muscle 7: Internet 8: Small diameter reinforcing bars 9: Sheet material 10: Separator 21: Main reinforcement 22: Strength Distribution Muscles 23: Shear reinforcement
Claims
1. A method for constructing a structure, Step (a) involves fixing a formwork to a reinforcing material embedded in the structure, and filling the inside of the formwork with concrete to form the interior of the structure. (b) A step of forming the outer shell of the structure by applying a hardening agent made of cement-based material to the inner outer surface of the structure, The structure is constructed by, A method for constructing a structure, characterized in that reinforcing bars to be embedded in the outer shell are arranged outside the formwork.
2. The method for constructing a structure according to claim 1, characterized in that the formwork is made of lath mesh, and the lath mesh is left on the outer surface inside the structure.
3. Shear reinforcement bars are embedded inside the aforementioned structure. A method for constructing a structure according to claim 1, characterized in that the lateral pressure during the filling of the concrete is supported by the shear reinforcement bars.
4. The method for constructing a structure according to claim 1, characterized in that the formwork is fixed to the inside of the main reinforcement bars and distribution reinforcement bars, which are reinforcing materials of the structure and embedded in the outer shell.
5. The method for constructing a structure according to claim 1, characterized in that the formwork is fixed using a fixing jig.
6. Shear reinforcement bars are embedded inside the aforementioned structure. The method for constructing a structure according to claim 5, characterized in that a fixing jig for the end of the shear reinforcement bar is used as the fixing jig.