Concrete structure reinforcing method, and concrete structure assembly

Abstract

Provided are a concrete structure assembly and a concrete structure reinforcing method with which a concrete structure buried in the ground can be easily reinforced from the outside. This concrete structure (10) reinforcing method serves to reinforce a concrete structure (10) that is embedded in the ground and has a bottomed cylindrical shape, the method being characterized by including: removing a lid (40) that closes an upper end part of the concrete structure (10); excavating a ground (E) outside a peripheral wall (11) of the concrete structure (10); loading an uncured foundation member (mortar) in a mined area (S) in the ground (E), and integrating the same with the peripheral wall (11); placing an annular member (30) so as to be supported from below by an upper end part of the peripheral wall (11) and an upper end part of the cured foundation member; and installing the lid (40) on the upper side of the annular member (30).

Description

Method for reinforcing a concrete structure and concrete structure assembly

[0001] This disclosure relates to a method for reinforcing a concrete structure and a concrete structure assembly.

[0002] Since facilities exposed to the external environment deteriorate over time, reinforcement techniques are being developed for concrete structures buried underground. For example, in the case of a cylindrical handhole made of concrete with a bottom, it has been disclosed that deterioration of the handhole can be suppressed by installing a reinforcing member such as an aramid fiber sheet inside the handhole (for example, Non-Patent Document 1).

[0003] Airec Giken Co., Ltd., "Handhole reinforcement technology," [online], [searched May 31, 2023], Internet: <https: / / www.airec.co.jp / products / renovation / handhole.html>

[0004] However, with the method disclosed in Non-Patent Document 1, if there are a large number of cables and hardware inside the handhole, the space available for installing the reinforcing member is limited. As a result, there are cases where the limited reinforcing member alone is not enough to sufficiently suppress deterioration of the handhole, and there is room for improvement in this regard.

[0005] Therefore, in consideration of the above points, an object of the present disclosure is to provide a method for reinforcing a concrete structure and a concrete structure assembly that can easily reinforce a concrete structure buried underground from the outside.

[0006] In order to solve the above problems, the method of reinforcing a concrete structure according to the present disclosure is a method of reinforcing a concrete structure buried in the ground and having a cylindrical shape with a bottom, and is characterized by including: removing a lid that closes the upper end of the concrete structure; excavating the ground outside the peripheral wall of the concrete structure; filling the excavated area of ​​the ground with unhardened foundation material to integrate it with the peripheral wall; placing a ring-shaped member so that it is supported from below by the upper end of the peripheral wall and the upper end of the hardened foundation material; and installing the lid above the ring-shaped member.

[0007] In addition, 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; a foundation portion integrally formed on the outside of the peripheral wall of the concrete structure; a ring-shaped member supported from below by the upper end of the peripheral wall and the upper end of the foundation portion; and a lid body installed above the ring-shaped member and closing the upper end of the concrete structure.

[0008] According to the present disclosure, it is possible to provide a method for reinforcing a concrete structure and a concrete structure assembly that can easily reinforce a concrete structure buried underground from the outside.

[0009] Fig. 1 is a front cross-sectional view of a concrete structure assembly according to an embodiment of the present disclosure; Fig. 2 is a flowchart showing the procedure for carrying out a method for reinforcing a concrete structure according to an embodiment of the present disclosure; Fig. 3 is a front cross-sectional view showing each step of the method for reinforcing a concrete structure according to an embodiment of the present disclosure; Fig. 4 is a front cross-sectional view showing each step of the method for reinforcing a concrete structure according to an embodiment of the present disclosure;

[0010] Hereinafter, a concrete structure assembly 100 according to an embodiment of the present disclosure and a method for reinforcing a concrete structure 10 will be described with reference to the drawings.

[0011] The concrete structure assembly 100 according to this embodiment is a structure assembly for forming so-called handholes, manholes, etc. As shown in Fig. 1, the concrete structure assembly 100 includes a concrete structure 10 buried in the ground and having a cylindrical shape with a bottom, a mortar base 20 integrally provided on the outside of a peripheral wall 11 of the concrete structure 10, a ring-shaped member 30 supported from below by the upper end of the peripheral wall 11 and the upper end of the base 20, and a lid 40 disposed above the ring-shaped member 30 and closing the upper end of the concrete structure 10. In this embodiment, mortar is the base material for forming the base 20.

[0012] 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.

[0013] The concrete structure 10 is a concrete box having a cylindrical structure with a bottom and a rectangular outer shape in a plan view. The concrete structure 10 has a peripheral wall 11 that surrounds an internal space N from the outside in the left-right and depth directions, and a bottom wall 13 that closes the lower end of the peripheral wall 11. The peripheral wall 11 has a through-hole (not shown), and a cable pipe 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 concrete structure 10 is made of inexpensive unreinforced concrete that does not use reinforcing bars, but the concrete structure 10 is not limited to this form. Furthermore, the concrete structure 10 may have a shape other than a rectangular shape in a plan view, such as a substantially circular shape.

[0014] A mortar foundation 20 is integrally provided on the outside of the peripheral wall 11 of the concrete structure 10. The foundation 20 surrounds the peripheral wall 11 from the outside, and in this embodiment, has a rectangular outer shape in plan view, similar to the peripheral wall 11. The foundation 20 can be firmly adhered to the outer surface of the peripheral wall 11 of the concrete structure 10 using, for example, an epoxy resin-based two-component joint adhesive. Note that the peripheral wall 11 and the foundation 20 may be fixed together using other types of adhesives or by methods other than adhesives.

[0015] In this specification, claims, etc., the terms "integrate" and "integrally provided" refer to a state in which the foundation portion 20 is firmly fixed to the peripheral wall 11 of the concrete structure 10 in an undetachable manner.

[0016] The mortar used for the foundation 20 can be, for example, a high-filling, ultra-rapid-setting mortar that has low viscosity in an unhardened state. This allows the mortar to be quickly poured into the area S (see FIG. 3A ) excavated outside the peripheral wall 11 of the concrete structure 10 to quickly form the foundation 20. By providing the mortar foundation 20 outside the peripheral wall 11, the load applied from the ground via the annular member 30 can be distributed between the concrete structure 10 and the foundation 20. This prevents deterioration of the concrete structure 10, allowing the concrete structure 10 to continue to be used safely for a long period of time.

[0017] An annular member 30 is placed on the upper end of the peripheral wall 11 and the upper end of the foundation 20 of the concrete structure 10. As shown in FIG. 1 , the annular member 30 includes a circular concrete base material 31 placed on the upper end of the peripheral wall 11 and the upper end of the foundation 20, and an annular metal member 32 placed on the upper surface of the annular base material 31. The annular base material 31 and the annular metal member 32 have substantially the same cross-sectional shape in a plan view, and in this embodiment, the outer shape is substantially rectangular so as to cover the upper ends of the peripheral wall 11 and the foundation 20 from above. However, the annular member 30 may have a shape other than a rectangle, such as a substantially circular shape, to match the shape of the peripheral wall 11, etc. in a plan view.

[0018] As described above, the annular member 30 of this embodiment has a double structure including the annular base material 31 made of concrete and the annular metal member 32 made of metal. With this configuration, when the lid body 40 (described later) is placed above the annular member 30, the lid body 40 is directly supported from below by the hard annular metal member 32, thereby suppressing deformation of the lid body 40. Therefore, the load from the ground can be transmitted evenly to the annular member 30.

[0019] In this embodiment, the material of the annular base material 31 may be, for example, ultra-high strength fiber reinforced concrete (UFC) such as Ductal (registered trademark) concrete. Furthermore, the material of the annular metal member 32 may be, for example, a general structural rolled steel such as SS400. However, the present invention is not limited to these embodiments, and various other materials may be used for the annular base material 31 and the annular metal member 32.

[0020] The lid body 40 includes an upper lid 41 that closes the concrete structure 10, and a receiving frame 42 into which the upper lid 41 fits. In this embodiment, the upper lid 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 lid 41 is fitted into the receiving frame 42 and thereby closes the upper end of the concrete structure 10. In this embodiment, the upper lid 41 can be made of cast iron such as spheroidal graphite cast iron (FCD700). The upper lid 41 may have an outer shape other than a rectangular shape, such as a substantially circular shape.

[0021] 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 annular member 30. 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 other than a rectangular shape, such as a substantially circular shape.

[0022] When manufacturing the concrete structure assembly 100 having the above configuration, workers remove the cover 40 and the annular member 130 that was previously used from the "(1) Before Construction" state shown in FIG. 3A (step S101 in FIG. 2). After removing the cover 40 and other components, the ground E outside the circumferential wall 11 of the concrete structure 10 is excavated to form an area S (step S102 in FIG. 2), as shown in "(2) Removal of Cover and Excavation of Ground" in FIG. 3A. This excavation of the ground E is intended to provide an area S for forming the mortar foundation 20 outside the circumferential wall 11. Therefore, as shown in "(2) Removal of Cover and Excavation of Ground" in FIG. 3A, it is preferable to excavate the space above the area S in addition to the area S for forming the foundation 20. It is preferable that the area S formed by excavation be provided only on the outside of the upper portion of the circumferential wall 11. This allows the placement of the foundation 20 for dispersing the load on the concrete structure 10 to be limited to the outer side of the upper part of the perimeter wall 11. Therefore, the foundation 20 can be placed without being obstructed by buried objects such as pipelines, and the load on the concrete structure 10 can be dispersed.

[0023] The height position at which the region S and the foundation portion 20 are provided is preferably within half the total height of the peripheral wall 11 from the upper end of the peripheral wall 11 .

[0024] It is preferable to thoroughly clean the outer surface of the peripheral wall 11 that contacts the area S to prevent contamination by soil or the like from the ground E. This allows the outer surface of the peripheral wall 11 and the mortar base 20 to be fixed with a predetermined adhesive strength in the next step.

[0025] Next, the worker applies adhesive to the outer surface of the peripheral wall 11 that contacts the area S (step S103 in FIG. 2). This adhesive is applied to improve the adhesion between the mortar and the outer surface of the peripheral wall 11 when unhardened mortar is filled into the area S formed by excavation in the next step. For example, an epoxy resin-based two-component joint adhesive can be used as the adhesive.

[0026] Next, workers fill unhardened mortar into the area S outside the excavated perimeter wall 11, and harden it to form the foundation 20 (see step S104 in FIG. 2 and "(3) Filling mortar" in FIG. 3A). The mortar to be filled into the area S can be, for example, a high-filling, ultra-fast-hardening mortar that has low viscosity in an unhardened state. This allows the mortar to be quickly poured into the area S (see FIG. 3A) excavated outside the perimeter wall 11 of the concrete structure 10, quickly forming the foundation 20. The viscosity and other properties of the mortar can be selected appropriately depending on the required dimensional accuracy, formation time, etc.

[0027] Next, the worker places the annular member 30 so that it is supported from below by the upper end of the peripheral wall 11 and the upper end of the hardened mortar (see step S105 in FIG. 2 and "(4) Placing the annular member" in FIG. 3B). As described above, the annular member 30 has a dual structure including a circular concrete base member 31 placed on the upper end of the peripheral wall 11 and the upper end of the foundation 20, and a circular metal member 32 placed on the upper surface of the base member 31. With this configuration, when the cover 40 is placed above the annular member 30, the cover 40 is directly supported from below by the hard annular metal member 32, thereby suppressing deformation of the cover 40. Note that the annular member 30 does not necessarily have to have a dual structure and may be, for example, a plate-shaped annular member made of ultra-high-strength fiber-reinforced concrete or metal.

[0028] Next, the worker places the lid 40 on the annular member 30 (see step S106 in FIG. 2 and "(5) Placement of the lid" in FIG. 3B). To place the lid 40, first place the receiving frame 42 on the annular base material 31, and then fit the outer edge of the upper lid 41 into the recess of the receiving frame 42 to close the upper end of the concrete structure 10. Also, as shown in "(5) Placement of the lid" in FIG. 3B, it is preferable to backfill the area outside the lid 40 with soil.

[0029] As described above, the reinforcement method for the concrete structure 10 according to this embodiment is a method for reinforcing the concrete structure 10, which is buried underground and has a cylindrical shape with a bottom, and includes the steps of removing the cover 40 covering the upper end of the concrete structure 10, excavating the ground E outside the peripheral wall 11 of the concrete structure 10, filling the excavated area S of the ground E with unhardened foundation material (mortar) to integrate it with the peripheral wall 11, placing the annular member 30 so that it is supported from below by the upper end of the peripheral wall 11 and the upper end of the hardened foundation material, and installing the cover 40 above the annular member 30. By adopting this configuration, the load applied from the ground to the concrete structure 10 through the cover 40 can be distributed to the foundation 20. Therefore, deterioration of the concrete structure 10 can be suppressed, allowing the concrete structure 10 to continue to be used safely for a long period of time.

[0030] Furthermore, in this embodiment, the method further includes applying an adhesive to the outer surface of the peripheral wall 11 that contacts the mined area S in the ground E. By adopting such a configuration, the adhesion between the foundation 20 and the outer surface of the peripheral wall 11 can be improved, so that the load from the ground that is applied to the concrete structure 10 through the lid 40 can be more reliably distributed to the foundation 20, thereby suppressing deterioration of the concrete structure 10.

[0031] In this embodiment, the annular member 30 is configured to include a concrete annular base material 31 and an annular metal member 32 placed on the upper surface of the annular base material 31. By adopting this configuration, when the lid body 40 is placed above the annular member 30, the lid body 40 is directly supported from below by the hard annular metal member 32, thereby suppressing deformation of the lid body 40. Therefore, the load from the ground can be transmitted evenly to the annular member 30.

[0032] In this embodiment, the lid body 40 is configured to have an upper lid 41 that closes the concrete structure 10 and a receiving frame 42 into which the upper lid 41 fits. By adopting such a configuration, the upper lid 41 can be easily positioned by fitting the upper lid 41 into the recess of the receiving frame 42, thereby closing the concrete structure 10.

[0033] In this embodiment, the excavation of the ground E outside the peripheral wall 11 is configured to excavate the ground E outside the upper part of the peripheral wall 11. By adopting such a configuration, the foundation 20 for distributing the load on the concrete structure 10 can be placed only outside the upper part of the peripheral wall 11. Therefore, the foundation 20 can be placed without being obstructed by buried objects such as pipelines, and the load on the concrete structure 10 can be distributed.

[0034] In this embodiment, the foundation material is mortar. By adopting this configuration, the foundation 20 for dispersing the load on the concrete structure 10 can be easily formed in the ground E by forming an area S in the ground E and filling it with mortar.

[0035] Furthermore, the concrete structure assembly 100 according to this embodiment is configured to include a concrete structure 10 buried in the ground and having a cylindrical shape with a bottom, a foundation 20 provided integrally with the outer side of a peripheral wall 11 of the concrete structure 10, an annular member 30 supported from below by the upper end of the peripheral wall 11 and the upper end of the foundation 20, and a lid 40 installed above the annular member 30 and closing the upper end of the concrete structure 10. By adopting this configuration, the load applied from the ground to the concrete structure 10 can be distributed to the foundation 20 through the lid 40. Therefore, deterioration of the concrete structure 10 can be suppressed, and the concrete structure 10 can be used safely for a long period of time.

[0036] 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.

[0037] For example, in the present embodiment, the peripheral wall 11 and the foundation 20 of the concrete structure 10 are firmly fixed together by bonding them with an adhesive, but the present invention is not limited to this. The peripheral wall 11 and the foundation 20 may be firmly fixed together by adhesive strength obtained during the hardening process of mortar.

[0038] In addition, in this embodiment, the concrete structure assembly 100 is formed by filling unhardened mortar into the area S excavated from the ground E, but this is not limited to this. For example, the concrete structure assembly 100 may be manufactured by placing the foundation 20 formed in advance in a separate process in the excavated area S and fixing it to the peripheral wall 11 by adhesive or the like. The foundation 20 may also be formed from a material other than mortar.

[0039] The following additional notes are provided regarding the above-described embodiments.

[0040] (Supplementary Item 1) A method for reinforcing a concrete structure buried in the ground and having a cylindrical shape with a bottom, comprising: removing a lid closing the upper end of the concrete structure; excavating the ground outside the peripheral wall of the concrete structure; filling the excavated area of ​​the ground with unhardened foundation material to integrate it with the peripheral wall; placing an annular member so that it is supported from below by the upper end of the peripheral wall and the upper end of the hardened foundation material; and installing the lid above the annular member. (Supplementary Item 2) The method for reinforcing a concrete structure according to Supplementary Item 1, further comprising applying an adhesive to an outer surface of the peripheral wall that contacts the excavated area of ​​the ground. (Supplementary Item 3) The method for reinforcing a concrete structure according to Supplementary Item 1 or 2, wherein the annular member comprises a circular concrete base material and a circular metal member placed on the upper surface of the circular base material. (Supplementary Item 4) The method for reinforcing a concrete structure according to any one of Supplementary Items 1 to 3, wherein the lid has an upper lid that closes the concrete structure and a receiving frame into which the upper lid fits. (Supplementary Item 5) The method for reinforcing a concrete structure according to any one of Supplementary Items 1 to 4, wherein the excavation of the ground outside the peripheral wall is excavation of the ground outside an upper part of the peripheral wall. (Supplementary Item 6) The method for reinforcing a concrete structure according to any one of Supplementary Items 1 to 5, wherein the foundation material is mortar. (Supplementary Item 7) A concrete structure assembly comprising: a concrete structure buried in the ground and having a cylindrical shape with a bottom; a foundation provided integrally with the outside of the peripheral wall of the concrete structure; an annular member supported from below by an upper end of the peripheral wall and an upper end of the foundation; and a lid placed above the annular member and closing the upper end of the concrete structure.

[0041] REFERENCE SIGNS LIST 10 Concrete structure 11 Peripheral wall 13 Bottom wall 20 Foundation 30 Annular member 31 Annular base material 32 Annular metal member 40 Lid 41 Upper lid 42 Receiving frame 100 Concrete structure assembly 130 Annular member E Ground N Internal space S Area

Claims

1. A method of reinforcing a concrete structure buried in the ground and having a cylindrical shape with a bottom, comprising: removing a lid covering an upper end of the concrete structure; excavating the ground outside the peripheral wall of the concrete structure; filling the excavated area of ​​the ground with unhardened foundation material to integrate it with the peripheral wall; placing a ring-shaped member so that it is supported from below by the upper end of the peripheral wall and the upper end of the hardened foundation material; and installing the lid above the ring-shaped member.

2. The method of reinforcing a concrete structure according to claim 1, further comprising applying an adhesive to an outer surface of said perimeter wall that abuts an excavated area of ​​the ground.

3. A method for reinforcing a concrete structure as described in claim 1 or 2, wherein the annular member comprises a ring-shaped concrete base material and a ring-shaped metal member placed on the upper surface of the ring-shaped base material.

4. A method for reinforcing a concrete structure as described in claim 1 or 2, wherein the lid body has an upper lid that closes the concrete structure and a receiving frame into which the upper lid fits.

5. A method for reinforcing a concrete structure as described in claim 1 or 2, wherein the excavation of the ground outside the peripheral wall is the excavation of the ground outside the upper part of the peripheral wall.

6. The method for reinforcing a concrete structure according to claim 1 or 2, wherein the foundation material is mortar.

7. A concrete structure assembly comprising: a concrete structure buried in the ground and having a cylindrical shape with a bottom; a foundation portion integrally formed on the outside of the peripheral wall of the concrete structure; a ring-shaped member supported from below by an upper end of the peripheral wall and an upper end of the foundation portion; and a lid body installed above the ring-shaped member and closing the upper end of the concrete structure.

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