Concrete structure assembly and method for manufacturing concrete structure assembly

Abstract

Provided are a concrete structure assembly that is capable of performing necessary reinforcement thereon while minimizing narrowing of an internal space to a concrete structure buried in the ground, and a method for manufacturing the concrete structure assembly. The concrete structure assembly (100) according to the present disclosure is characterized by comprising: a concrete structure (10) that is buried in the ground and has a bottomed cylindrical shape, the concrete structure (10) having a peripheral wall (11) and a bottom wall (13) that closes the lower end part of the peripheral wall (11); and a reinforcing wall (20) that is provided only on the upper surface of the bottom wall (13) of the concrete structure (10), the reinforcing wall being integrated with the bottom wall (13).

Description

Concrete structure assembly and method for manufacturing the same

[0001] FIELD OF THE DISCLOSURE This disclosure relates to concrete structural assemblies and methods for manufacturing concrete structural assemblies.

[0002] The development of reinforcement technology for concrete structures buried underground is progressing. For example, take the concrete cylindrical handholes with bottoms. In the past, handholes installed at the edge of roads were designed to withstand the weight of people and other loads. For this reason, it is assumed that some of these handholes are made of unreinforced concrete without using rebar.

[0003] However, while road widths have been expanded in recent years, handholes that were previously installed at the edge of roads remain in the same locations, and it is anticipated that they may not necessarily be located at the edge of the expanded road. Therefore, since the weight of a vehicle may be placed on handholes that were designed on the assumption that the weight of a person or the like will be placed on them, a construction method has been disclosed in which the four corners of handholes that lack strength are reinforced with steel materials and an aramid fiber sheet or the like is placed on the inner surface, thereby reinforcing the insufficient strength of the handholes without excavation (for example, Non-Patent Document 1).

[0004] Airec Giken Co., Ltd., "Handhole reinforcement technology," [online], [searched December 4, 2023], Internet: <https: / / www.airec.co.jp / products / renovation / handhole.html>

[0005] However, with the method disclosed in Non-Patent Document 1, when reinforcing members such as steel members are installed at the four corners of the inside of the handhole, the space inside the handhole becomes narrow. Therefore, if there are a large number of cables and hardware equipment to be housed inside, it may not be possible to arrange them inside the reinforced handhole, and there is room for improvement in this regard.

[0006] Therefore, in consideration of the above points, an object of the present disclosure is to provide a concrete structure assembly and a method for manufacturing a concrete structure assembly that can provide necessary reinforcement to a concrete structure buried underground while minimizing narrowing of the internal space.

[0007] In order to solve the above-mentioned problems, the concrete structure assembly according to the present disclosure is characterized by comprising: a concrete structure buried in the ground and having a cylindrical shape with a bottom, the concrete structure having a peripheral wall and a bottom wall that closes the lower end of the peripheral wall; and a reinforcing wall that is provided integrally with the bottom wall only on the upper surface of the bottom wall of the concrete structure.

[0008] In addition, in order to solve the above-mentioned problems, the manufacturing method of a concrete structure assembly according to the present disclosure is a manufacturing method of a concrete structure assembly that reinforces a concrete structure that is buried underground and has a cylindrical shape with a bottom, wherein the concrete structure has a peripheral wall and a bottom wall that closes the lower end of the peripheral wall, and the manufacturing method of the concrete structure assembly is characterized in that it includes providing a reinforcing wall integrally with the bottom wall only on the upper surface of the bottom wall of the concrete structure.

[0009] According to the present disclosure, it is possible to provide a concrete structure assembly and a method for manufacturing a concrete structure assembly that can provide necessary reinforcement to a concrete structure buried underground while minimizing narrowing of the internal space.

[0010] Fig. 1 is a front cross-sectional view of a concrete structure assembly according to one embodiment of the present disclosure. Fig. 2 is a conceptual diagram showing distortion of each portion when a load is applied to a concrete structure assembly. Fig. 3 is a flowchart showing the procedure for implementing a method for manufacturing a concrete structure assembly according to one embodiment of the present disclosure. Fig. 4 is a front cross-sectional view showing each step (first half) of a method for manufacturing a concrete structure assembly according to one embodiment of the present disclosure. Fig. 5 is a front cross-sectional view showing each step (second half) of a method for manufacturing a concrete structure assembly according to one embodiment of the present disclosure.

[0011] Hereinafter, a concrete structure assembly 100 according to an embodiment of the present disclosure and a method for manufacturing the concrete structure assembly 100 will be described with reference to the drawings.

[0012] The concrete structure assembly 100 according to this embodiment is a structure assembly for forming a so-called handhole, manhole, or the like. As shown in FIG. 1 , the concrete structure assembly 100 includes a cylindrical concrete structure 10 buried in ground E, which has a peripheral wall 11 and a bottom wall 13 that closes the lower end of the peripheral wall 11, and a mortar reinforcing wall 20 that is provided integrally with and along the upper surface of the bottom wall 13 of the concrete structure 10. That is, the concrete structure assembly 100 is a structure reinforced by providing the reinforcing wall 20 on the upper surface of the bottom wall 13 of the concrete structure 10 buried in the ground. The concrete structure assembly 100 also includes a cover 40 that is disposed on the upper end of the peripheral wall 11 and closes the upper end of the concrete structure assembly 100. In this embodiment, mortar is the reinforcing material for forming the reinforcing wall 20.

[0013] The up-down direction, left-right direction and depth direction of the concrete structure assembly 100 correspond to the up-down direction, left-right direction and direction perpendicular to the plane of the paper in FIG.

[0014] The concrete structure 10 is a concrete box having a bottomed cylindrical structure with a rectangular outer shape in a plan view. The concrete structure 10 includes a peripheral wall 11 that surrounds an internal space N from the left-right and depth directions, and a bottom wall 13 that closes the lower end of the peripheral wall 11. A through-hole is provided in the peripheral wall 11, and a cable pipe 30 for laying cables such as communication cables and power transmission cables extends through the through-hole to the outside of the concrete structure 10. In this embodiment, the vertical distance from the upper surface of the bottom wall 13 to the lower end of the cable pipe 30 is 40 mm or more. Therefore, the thickness of the reinforcing wall 20 can be as thick as 40 mm. In this embodiment, the concrete structure 10 is formed of inexpensive unreinforced concrete without using rebar, but this is not limited to this configuration. Furthermore, the concrete structure 10 may have a shape other than a rectangular shape in a plan view, such as a substantially circular shape.

[0015] A mortar reinforcing wall 20 is integrally provided on the upper surface of the bottom wall 13 of the concrete structure 10. The reinforcing wall 20 is integrally formed with the bottom wall 13 only on the upper surface of the bottom wall 13 along the bottom wall 13. By reinforcing the upper surface of the concrete bottom wall 13 with the mortar reinforcing wall 20 in this way, as shown by the arrow in FIG. 2 , even if a large load that was not anticipated when the concrete structure 10 was manufactured and placed, such as the weight of a vehicle, is applied to the lid body 40, excessive tensile loads on the bottom wall 13 can be reduced. The load applied to the lid body 40 can be, for example, T-20 (a load of approximately 80 kN) as specified by the Ministry of Land, Infrastructure, Transport and Tourism.

[0016] That is, an excessive load applied to the cover 40 results in a large compressive stress on the peripheral wall 11, and the peripheral wall 11 presses the outer edge of the bottom wall 13 downward with a large force, causing the bottom wall 13 to warp upward and be pulled outward with a large tensile stress. In FIG. 2 , the distortions due to the compressive stress on the peripheral wall 11 and the tensile stress on the bottom wall 13 are indicated by dashed lines. In this embodiment, the reinforcing wall 20 is integrally formed with the bottom wall 13 along only the upper surface of the bottom wall 13. With this configuration, the tensile stress on the bottom wall 13 is suppressed by the reinforcing wall 20 provided on the upper surface of the bottom wall 13. Therefore, by integrally forming the reinforcing wall 20 with the bottom wall 13 along only the upper surface of the bottom wall 13, the concrete structure 10 can be reinforced without significantly reducing the internal space of the concrete structure 10 (although the height of the bottom portion increases slightly). This suppresses deterioration of the concrete structure 10, allowing the concrete structure 10 to be used safely for a long period of time.

[0017] For example, a high-filling, ultra-fast-setting mortar that has low viscosity in an unhardened state can be used as the material for the reinforcing wall 20. This allows the mortar to be quickly poured onto the top surface of the bottom wall 13 of the concrete structure 10, thereby quickly forming the reinforcing wall 20. However, this is not limiting, and a mortar with a high viscosity or a material other than mortar may also be used as the material for the reinforcing wall 20.

[0018] The reinforcing wall 20 can be firmly adhered to the upper surface of the bottom wall 13 of the concrete structure 10 by, for example, an epoxy resin-based two-component joint adhesive. Note that the bottom wall 13 and the reinforcing wall 20 may be fixed together using other types of adhesives or by a method other than adhesives.

[0019] It is preferable that the material of the reinforcing wall 20 has a higher tensile strength than the material of the bottom wall 13. This makes it possible to more reliably eliminate the lack of strength caused by excessive tensile stress applied to the bottom wall 13 of the concrete structure 10.

[0020] The thickness of the reinforcing wall 20 is preferably 25 mm or more. With this configuration, even when a load conforming to the T-20 standard is applied to the cover 40, the tensile stress generated in the bottom wall 13 can be kept below the allowable tensile stress of concrete. Furthermore, by making the thickness of the reinforcing wall 20 40 mm or less, interference between the reinforcing wall 20 and the cable pipe 30 can be suppressed.

[0021] In this specification, claims, etc., the terms "integrate" and "integrally provided" refer to a state in which the reinforcing wall 20 is firmly and irremovably fixed to the bottom wall 13 of the concrete structure 10.

[0022] The cover body 40 includes an upper cover 41 that closes the concrete structure assembly 100, and a receiving frame 42 into which the upper cover 41 fits. In this embodiment, the upper cover 41 is a plate-like member having a rectangular outer shape that is shorter in both the left-right and depth directions than the outer shape of the concrete structure 10. The upper cover 41 is fitted into the receiving frame 42 and thereby closes the upper end of the concrete structure assembly 100. In this embodiment, the upper cover 41 can be made of cast iron, such as spheroidal graphite cast iron (FCD700). The upper cover 41 may have an outer shape other than a rectangular shape, such as a substantially circular shape.

[0023] The receiving frame 42 is a frame member having a recess into which the top cover 41 fits. In this embodiment, the receiving frame 42 has a substantially rectangular outer shape corresponding to the outer shape of the top cover 41, and is installed on the upper surface of the peripheral wall 11. The receiving frame 42 may be made of cast iron such as spheroidal graphite cast iron (FCD600). The receiving frame 42 may also have an outer shape such as a substantially circular shape in addition to a rectangular shape.

[0024] When manufacturing the concrete structure assembly 100 having the above configuration (reinforcing the concrete structure 10), the worker temporarily removes the lid 40 and the stored contents S that had been stored in the concrete structure 10 up to that point, from the state of "(1) Before construction" shown in FIG. 4A, as shown in "(2) Temporary removal of the lid and stored contents" (step S101 in FIG. 3).

[0025] Next, after removing the cover 40 and the like in step S101, as shown in "(3) Surface Preparation" in Fig. 4A, a surface preparation is performed on the upper surface of the bottom wall 13 of the concrete structure 10 (step S102 in Fig. 3). This surface preparation on the upper surface of the bottom wall 13 includes, for example, cleaning the bottom wall 13 or surface treatment of a surface treatment area 60 on the upper surface of the bottom wall 13 using a metal brush or the like. Note that the surface treatment area 60 includes not only the upper surface of the bottom wall 13 but also the lower inner surface of the peripheral wall 11 with which the reinforcing wall 20 abuts.

[0026] After the base preparation in step S102, adhesive 50 is applied to the upper surface of the bottom wall 13 of the concrete structure 10 (step S103 in FIG. 3), as shown in "(4) Application of Adhesive" in FIG. 4B. As shown in FIG. 4B, adhesive 50 may be applied not only to the upper surface of the bottom wall 13 but also to the lower inner surface of the peripheral wall 11 against which the reinforcing wall 20 abuts. The adhesive 50 applied to the upper surface of the bottom wall 13 may be, for example, an epoxy resin-based two-component joint adhesive. However, this is not limited to this embodiment, and other types of adhesives may also be used. Furthermore, the reinforcing wall 20 may be fixed to the bottom wall 13 by a method other than an adhesive.

[0027] After applying the adhesive 50 in step S103, the reinforcing wall 20 is placed on the upper surface of the bottom wall 13 (step S104 in FIG. 3 ), as shown in “(5) Installing the reinforcing wall” in FIG. 4B . The reinforcing wall 20 can be quickly formed by, for example, quickly pouring a high-fill, ultra-fast-hardening mortar, which has low viscosity in an unhardened state, onto the upper surface of the bottom wall 13 of the concrete structure 10. However, the present invention is not limited to this, and the reinforcing wall 20 may be made of a high-viscosity mortar or a material other than mortar.

[0028] In the present specification and claims, "a reinforcing wall provided only on the upper surface of the bottom wall" means that the reinforcing wall 20 is provided on the upper surface of the bottom wall, and the reinforcing wall 20 is not provided along the inner surface of the peripheral wall 11. Note that even if the reinforcing wall 20 is provided on the upper surface of the bottom wall 13 along the bottom wall 13 and the outer edge of the reinforcing wall 20 abuts against the inner surface of the lower part of the peripheral wall 11, this does not mean that the reinforcing wall 20 is provided along the inner surface of the peripheral wall 11, and it is a "reinforcing wall provided only on the upper surface of the bottom wall."

[0029] After the reinforcing wall 20 is installed in step S104, the stored object S is returned to the internal space N of the concrete structure 10 and the internal space N is covered with the lid 40, as shown in "(6) Completed" in Fig. 4B, thereby completing the installation of the concrete structure assembly 100. In this embodiment, since the cable pipe 30 is disposed 40 mm or more above the upper surface of the bottom wall 13, even if the thickness of the reinforcing wall 20 is increased to 40 mm, the reinforcing wall 20 will not interfere with the cable pipe 30.

[0030] The concrete structure assembly 100 and the manufacturing method for the concrete structure assembly 100 according to this embodiment do not require as many steps as the method described in Patent Document 1, and the only area reinforced is the upper surface of the bottom wall 13. Therefore, as shown in Table 1 below, the construction period can be shortened by about two days compared to the reinforcing method described in Patent Document 1.

[0031]

[0032] In the method described in Patent Document 1, installing the reinforcing material requires many steps, such as applying an acrylic resin primer to the top surface of the bottom wall, attaching aramid resin, and applying an acrylic resin top coat, as well as installing steel members at the four corners of the peripheral wall, and therefore requires a long installation time of approximately 15 hours. In contrast, in the manufacturing method for the concrete structure assembly 100 of this embodiment, it is only necessary to pour mortar onto the top surface of the bottom wall 13 of the concrete structure 10 to form the reinforcing wall 20, and the installation time for the reinforcing material can be shortened to approximately 4 hours.

[0033] As described above, the concrete structure assembly 100 according to this embodiment is a concrete structure 10 buried underground and having a cylindrical shape with a bottom. The concrete structure 10 has a peripheral wall 11 and a bottom wall 13 closing the lower end of the peripheral wall 11, and is configured to include a reinforcing wall 20 provided integrally with the bottom wall 13 only on the upper surface of the bottom wall 13 of the concrete structure 10. By adopting this configuration, the tensile stress acting on the bottom wall 13 is suppressed by the reinforcing wall 20 provided on the upper surface of the bottom wall 13. Therefore, by forming the reinforcing wall 20 integrally with the bottom wall 13 only on the upper surface of the bottom wall 13 along the bottom wall 13, it is possible to reinforce the concrete structure 10 for its insufficient strength without significantly reducing the internal space of the concrete structure 10 (by only slightly increasing the height of the bottom). This suppresses deterioration of the concrete structure 10, allowing the concrete structure 10 to be used safely for a long period of time.

[0034] In this embodiment, the tensile strength of the material of the reinforcing wall 20 is set to be greater than the tensile strength of the material of the bottom wall 13. By adopting such a configuration, it is possible to more reliably eliminate the lack of strength caused by excessive tensile stress applied to the bottom wall 13 of the concrete structure 10.

[0035] In this embodiment, the thickness of the reinforcing wall is set to 25 mm or more, which makes it possible to suppress excessive tensile stress acting on the bottom wall 13 of the concrete structure 10 to an allowable tensile stress or less.

[0036] Furthermore, the manufacturing method of the concrete structure assembly 100 according to this embodiment is a method for manufacturing the concrete structure assembly 100 by reinforcing a concrete structure 10 having a cylindrical shape and a bottom and buried underground. The concrete structure 10 has a peripheral wall 11 and a bottom wall 13 closing the lower end of the peripheral wall 11. The manufacturing method of the concrete structure assembly 100 is configured to include providing a reinforcing wall 20 integrally with the bottom wall 13 only on the upper surface of the bottom wall 13 of the concrete structure 10. By adopting this configuration, the tensile stress acting on the bottom wall 13 is suppressed by the reinforcing wall 20 provided on the upper surface of the bottom wall 13. Therefore, by forming the reinforcing wall 20 integrally with the bottom wall 13 only on the upper surface of the bottom wall 13 along the bottom wall 13, it is possible to reinforce the concrete structure 10 for its insufficient strength without significantly reducing the internal space of the concrete structure 10 (by only slightly increasing the height of the bottom). Therefore, deterioration of the concrete structure 10 can be suppressed, allowing the concrete structure 10 to be used safely for a long period of time.

[0037] Although the present disclosure has been described based on the drawings and examples, it should be noted that those skilled in the art would easily be able to make various modifications and alterations based on the present disclosure. Therefore, it should be noted that these modifications and alterations are included within the scope of the present invention. For example, the functions included in each component, step, etc. can be rearranged so as not to cause logical inconsistencies, and multiple components, steps, etc. can be combined or divided into one.

[0038] For example, in the present embodiment, the bottom wall 13 and the reinforcing wall 20 of the concrete structure 10 are firmly fixed together by bonding them with the adhesive 50, but the present invention is not limited to this. The bottom wall 13 and the reinforcing wall 20 may be firmly fixed together by adhesive strength obtained during the hardening process of mortar.

[0039] In addition, in this embodiment, the reinforcing wall 20 is formed by filling the area on the top surface of the bottom wall 13 with unhardened mortar, but this is not limited to this. For example, the concrete structure assembly 100 may be manufactured by placing the reinforcing wall 20 formed in advance in a separate process on the top surface of the bottom wall 13 and fixing it to the bottom wall 13 by adhesive or the like. The reinforcing wall 20 may also be formed from a material other than mortar.

[0040] In order to confirm the reinforcing effect of the above embodiment, a finite element analysis was carried out on a solid model of the concrete structure assembly 100 of this embodiment, and the effect of reducing the tensile stress acting on the bottom wall 13 was confirmed.

[0041] In carrying out the finite element method analysis, the values ​​shown in Table 2 were used as the physical property values ​​of each part. In addition, the conditions shown in Table 3 were used as the constraint conditions between each member. The loading condition was that a T-20 load (80 kN) was applied to the lid 40.

[0042] The dimensions of the concrete structure 10 are as follows: external dimensions (left and right): 1000 mm, (depth): 600 mm, (top and bottom): 800 mm; internal dimensions (left and right): 800 mm, (depth): 400 mm, (top and bottom): 650 mm.

[0043]

[0044]

[0045] The analysis results are shown in Table 4 below. As shown in the "Allowable Stress" row in the table, when the allowable compressive stress, tensile stress, and shear stress for the peripheral wall 11 and bottom wall 13 were -5.4 MPa, 0.29 MPa, and 0.85 MPa, respectively, the tensile stress applied to the bottom wall 13 exceeded the allowable tensile stress of 0.29 MPa when there was no reinforcing wall 20 and when the reinforcing wall 20 was 20 mm thick (only "Tensile Stress" is marked "No" in Table 4). This is because the compressive stress applied to the peripheral wall 11 caused the bottom wall 13 to warp upward in a convex shape and was pulled outward with a large tensile stress. On the other hand, when the thickness of the reinforcing wall 20 is 25 mm or more, the tensile stress generated in the bottom wall 13 is below the allowable tensile stress of 0.29 MPa ("Tensile stress" is shown as "Good" in Table 4). This shows that providing a reinforcing wall 20 with a thickness of 25 mm or more effectively reinforces the insufficient tensile strength of the bottom wall 13. It was also found that the compressive stress and shear stress were below the allowable stress in both the peripheral wall 11 and the bottom wall 13, regardless of the thickness of the reinforcing wall 20 (both "Compressive stress" and "Shear stress" are shown as "Good" in Table 4). When the allowable stress is smaller than the value listed in Table 4, increasing the thickness of the reinforcing wall 20 is expected to have the effect of reinforcing the insufficient tensile strength of the bottom wall 13.

[0046]

[0047] The above finite element analysis revealed that by making the thickness of the reinforcing wall 20 25 mm or more, the tensile stress generated in the bottom wall 13 can be suppressed to below the allowable tensile stress even under a T-20 load.

[0048] The following additional notes are provided regarding the above-described embodiments.

[0049] (Supplementary Item 1) A concrete structure assembly comprising: a concrete structure buried in the ground and having a cylindrical shape with a bottom, the concrete structure having a peripheral wall and a bottom wall closing the lower end of the peripheral wall; and a reinforcing wall provided integrally with the bottom wall only on the upper surface of the bottom wall of the concrete structure. (Supplementary Item 2) The concrete structure assembly according to Supplementary Item 1, wherein the tensile strength of the reinforcing wall material is greater than the tensile strength of the bottom wall material. (Supplementary Item 3) The concrete structure assembly according to Supplementary Item 1 or 2, wherein the reinforcing wall has a thickness of 25 mm or more. (Supplementary Item 4) A method for manufacturing a concrete structure assembly reinforced from a cylindrical concrete structure buried in the ground and having a bottom, the concrete structure having a peripheral wall and a bottom wall closing the lower end of the peripheral wall, the method comprising providing a reinforcing wall integrally with the bottom wall only on the upper surface of the bottom wall of the concrete structure.

[0050] REFERENCE SIGNS LIST 10 Concrete structure 11 Peripheral wall 13 Bottom wall 20 Reinforcement wall 30 Cable conduit 40 Lid 41 Top lid 42 Receiving frame 50 Adhesive 60 Substrate preparation area 100 Concrete structure assembly E Ground N Internal space S Stored object

Claims

1. A concrete structure assembly, which is a concrete structure having a bottomed cylindrical shape and embedded in the ground, comprising: the concrete structure having a peripheral wall and a bottom wall closing the lower end of the peripheral wall; and a reinforcing wall provided integrally with the bottom wall only on the upper surface of the bottom wall of the concrete structure.

2. The concrete structure assembly according to claim 1, wherein the tensile strength of the material of the reinforcing wall is greater than the tensile strength of the material of the bottom wall.

3. The concrete structure assembly according to claim 1 or 2, wherein the thickness of the reinforcing wall is 25 [mm] or more.

4. A method for manufacturing a concrete structure assembly for reinforcing a concrete structure having a bottomed cylindrical shape and embedded in the ground, the concrete structure having a peripheral wall and a bottom wall closing the lower end of the peripheral wall, the method for manufacturing the concrete structure assembly including providing a reinforcing wall integrally with the bottom wall only on the upper surface of the bottom wall of the concrete structure.

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