Reinforcement bar installation structure and method

Abstract

To provide a reinforcing-bar embedded structure and a method capable of preventing transfer of axial compressive loads from the reinforcing-bar to a steel pipe, without inhibiting an adhesion effect between the reinforcing-bar and concrete in an area outside the steel pipe placement range.SOLUTION: A reinforcing-bar embedded structure 41 relating to the present invention is composed of a newly installed axial direction reinforcing-bar 37 embedded in concrete 34 in a form in which the reinforcing-bar is inserted through a steel pipe 38, and a tubular insulating member 42 made of a fiber-based material is inserted and positioned between the newly installed axial direction reinforcing-bar 37 and the steel pipe 38 so that the outer surface of the insulating member is in substantial contact with the inner surface of the steel pipe 38, and the separated space between the newly installed axial direction reinforcing-bar 37 and the insulating member 42 is filled with a filler 43. The insulating member 42 is arranged to block transmission of a compressive load along the axial direction of the newly installed axial direction reinforcing-bar 37 from the circumferential surface of the reinforcing-bar to the inner surface of the steel pipe 38 via the filler 43.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a reinforcing bar embedding structure and method that are primarily applicable to reinforced concrete. [Background technology]

[0002] When constructing structural members with reinforced concrete, in columns, tie bars are placed around the main bars, in beams, stirrups are placed around the main bars, and in walls, shear reinforcement is placed perpendicular to the wall surface to span the distribution bars that are placed perpendicular to the main bars.

[0003] These shear reinforcement bars, including tie bars and stirrups, have the functions of restraining the concrete and preventing buckling of the main bars, and the combined use of these functions can improve the toughness of reinforced concrete members.

[0004] On the other hand, since shear reinforcement bars are arranged by interlacing them with main reinforcement bars and distribution bars, construction tends to be inherently complicated. However, in cases where intermediate tie bars are essential, such as in large-section piers, the various types of reinforcement bars are interlaced in a more complex manner, making the arrangement extremely complicated, and there is a risk that the gap between the reinforcement bars, which is required to ensure the filling ability of the concrete, may not be sufficiently secured.

[0005] As a result, it may not be possible to place sufficient shear reinforcement bars, which could result in buckling of the main reinforcement bars, spalling of the cover concrete, and concrete collapse. In order to prevent this, measures are needed to suppress buckling of the main reinforcement bars.

[0006] Here, a configuration is known in which the main reinforcement bars are inserted into the circular pipe 1e to prevent the main reinforcement bars from buckling (Patent Document 1), but with the configuration described in this patent document, it is not possible to expect load transmission via adhesion between the circular pipe 1e and the concrete spreading around it, so cracks in the concrete spreading around the circular pipe 1e do not disperse in response to bending deformation, leading to the occurrence of localized cracks, and as a result, the stress at the compression edge becomes excessive, causing the concrete to collapse early, resulting in a structure with poor toughness.

[0007] In order to solve this problem, the applicant has discovered that by dividing the multiple main reinforcements into rebars inserted into steel pipes and embedded in concrete (main reinforcements belonging to a first group; hereinafter also referred to as the first main reinforcements) and rebars arranged so as to be embedded in the concrete and exposed to the concrete (main reinforcements belonging to a second group; hereinafter also referred to as the second main reinforcements), the second main reinforcements can exert their crack dispersion function, thereby preventing localized cracking in the concrete that would occur if only the first main reinforcements were used, and that the first main reinforcements can exert their own buckling prevention function via the steel pipes while also preventing buckling of the second main reinforcements by ensuring the soundness of the shear reinforcement (Patent Document 2). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 8-105157 [Patent Document 2] Patent Publication No. 2022-76500 Summary of the Invention [Problem to be solved by the invention]

[0009] According to the invention described in Patent Document 2, while load transmission between the steel pipe through which the first main reinforcement is inserted and the surrounding concrete cannot be expected as in the past, the second main reinforcement transmits load between the steel pipe and the surrounding concrete, thereby exerting the function of dispersing cracks that occur in the concrete. This makes it possible to avoid the situation in the past where localized cracks are caused by the circular pipe 1e and the concrete quickly collapses due to these cracks, and the first main reinforcement exerts its own anti-buckling function without being hindered by such early collapse of the concrete.

[0010] In addition, the first main bar is prevented from buckling by the steel pipe, which also reduces the burden on the shear reinforcement holding the first main bar. As a result, the shear reinforcement more securely restrains the internal concrete and also firmly holds the second main bar, preventing it from buckling.

[0011] As a result, both the first and second main bars are able to reliably absorb energy through hysteretic damping associated with compression and tension, thus making it possible to significantly improve the toughness of reinforced concrete.

[0012] However, when a compressive axial force is applied to a reinforcing bar inserted into a steel pipe, the filler material between the steel pipe and the reinforcing bar is pressed against the inner surface of the steel pipe due to the Poisson effect, and friction occurs between the steel pipe and the inner surface, causing a compressive load to be transmitted from the reinforcing bar to the steel pipe. In such a situation, the steel pipe used to prevent buckling itself becomes more susceptible to buckling, giving rise to the problem that there is a concern that the reinforcing bar's ability to prevent buckling may be reduced.

[0013] In addition, the compressive load flowing through the steel pipes had the same effect as if the amount of reinforcing steel had been increased, and due to the balance of the load borne by the reinforcing steel and the concrete, shear cracks in the concrete would occur first, reducing the deformation capacity and raising the concern that this could lead to shear failure.

[0014] One possible solution would be to apply a stripping agent to the inside of the steel pipe beforehand and then cover the reinforcing bar with it. However, this not only takes time to apply the agent, but also causes the stripping agent to migrate from the inside of the steel pipe to the periphery of the reinforcing bar when the steel pipe is being covered. If the stripping agent migrates beyond the buckling prevention range, i.e., beyond the range in which the steel pipe is arranged, it could impair the adhesion between the reinforcing bar and the concrete. [Means for solving the problem]

[0015] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a reinforcing bar embedding structure and method that can prevent axial compressive load from being transmitted from the reinforcing bar to the steel pipe without impeding the adhesion between the reinforcing bar and concrete in areas other than the area where the steel pipe is placed.

[0016] In order to achieve the above object, the reinforcing bar embedded structure according to the present invention comprises, as described in claim 1, a reinforcing bar embedded in a concrete structure. Each individual Steel Pipe Independently In the form of an insertion Together with the steel pipe In a structure with reinforcing bars embedded in concrete, A tubular insulating member made of a fibrous material is inserted and positioned between the reinforcing bar and the steel pipe, and a filler is filled in the space between the reinforcing bar and the insulating member with the outer peripheral surface of the insulating member substantially abutting the inner peripheral surface of the steel pipe, a filler is filled in the space between the insulating member and the steel pipe with the inner peripheral surface of the insulating member substantially abutting the outer peripheral surface of the reinforcing bar, or a filler is filled in the space between the reinforcing bar and the insulating member and the space between the insulating member and the steel pipe with the insulating member spaced apart from the inner peripheral surface of the steel pipe and the outer peripheral surface of the reinforcing bar, respectively, and the insulating member is configured to block the transmission of a compressive load along the axial direction of the reinforcing bar from the peripheral surface of the reinforcing bar to the inner peripheral surface of the steel pipe via the filler.

[0017] In addition, the reinforcing bar embedded structure of the present invention is configured such that the insulating member is inserted and positioned so that its outer peripheral surface substantially abuts the inner peripheral surface of the steel pipe, and the filler material is filled in the space between the reinforcing bar and the insulating member.

[0018] In addition, in the reinforcing bar embedded structure according to the present invention, the insulating member is formed by rolling the sheet material so that the edges of the sheet material overlap each other.

[0019] In addition, the reinforcing bar embedding method according to the present invention is as described in claim 4. Each individual Steel Pipe Independently After inserting the reinforcing bar, place the reinforcing bar together with the steel pipe in the concrete pouring area, or place the reinforcing bar in the concrete pouring area and then insert the reinforcing bar into the concrete pouring area. Each individual Steel Pipe Independently Then, concrete is poured into the concrete pouring area to insert the reinforcing bar into the steel pipe. Together with the steel pipe In a method for embedding reinforcing bars in concrete, A reinforcing bar embedding method comprising inserting and arranging a cylindrical insulating member made of a fiber-based material between the reinforcing bar and the steel pipe so that the outer peripheral surface of the insulating member substantially contacts the inner peripheral surface of the steel pipe, filling a space between the reinforcing bar and the insulating member with a filler, and then pouring concrete into the concrete pouring area, The insulating member is formed by rolling a sheet material so that edges of the sheet material overlap each other, When the insulating member is inserted between the reinforcing bar and the steel pipe, the insulating member is expanded in diameter by its restoring force, so that the outer peripheral surface of the insulating member substantially abuts against the inner peripheral surface of the steel pipe.

[0020] In addition, in the reinforcing bar embedding method according to the present invention, the filler is made of a hydraulic material, and the insulating member is configured so as to prevent water absorption therein.

[0021] In the reinforcing bar embedding structure and method of the present invention, when a reinforcing bar is inserted into a steel pipe and embedded in concrete, a tubular insulating member made of a fibrous material is inserted between the reinforcing bar and the steel pipe, and a filler material is filled in the space between the reinforcing bar and the insulating member, and a filler material is filled in the space between the insulating member and the steel pipe, or a filler material is filled in the space between the reinforcing bar and the insulating member and the space between the insulating member and the steel pipe, respectively, and the insulating member is configured to block the transmission of compressive load along the axial direction of the reinforcing bar from the peripheral surface of the reinforcing bar to the inner peripheral surface of the steel pipe via the filler material.

[0022] In this way, the compressive load generated in the axial direction of the reinforcing bar does not act on the steel pipe due to the load transmission blocking effect of the insulating member, even if the filler material between the reinforcing bar and the steel pipe expands laterally due to the Poisson effect, thus making it possible to prevent the steel pipe from buckling.

[0023] The reinforcing bar embedding structure and method of the present invention can be applied to reinforcing bar that is newly wrapped around existing reinforcing bar when carrying out earthquake reinforcement, but it can also be applied when constructing new reinforcing bar structures.

[0024] In the present invention, an insulating member made of a fibrous material is defined as a material in which various types of fibers, such as vegetable fibers and polymeric fibers, are intertwined and glued together. Ordinary paper is a typical example of this, but nonwoven fabrics are also included in this definition.

[0025] The load transmission blocking action of insulating materials is generally as follows: (a) Barrier action due to the fact that there is virtually no friction between the outer surface of the insulating material and the inner surface of the steel pipe. (b) Barrier effect due to the substantial absence of friction between the circumferential surface of the reinforcing bar and the inner circumferential surface of the insulating material. (c) The insulating material is made of a fiber-based material, and therefore the insulating material itself does not have shear resistance, resulting in an interrupting effect. In the case of (a), the filler is filled in the space between the reinforcing bar and the insulating material, in the case of (b), the space between the insulating material and the steel pipe, and in the case of (c), both of these spaces are filled with the filler.

[0026] Here, in the case of (b), when the reinforcing bar is a deformed reinforcing bar, a small clearance is formed between its circumferential surface and the insulating member, and there is a concern that the effect of the steel pipe in restraining the reinforcing bar in bending will be slightly reduced by the amount of that clearance. In the case of (c), if the insulating member has slight shear resistance, there is a concern that the load transmission and blocking effect of the insulating member will be reduced by that amount, and a small compressive load will be transmitted to the steel pipe. However, in the case of (a), that is, if the insulating member is inserted and positioned so that its outer circumferential surface substantially abuts the inner circumferential surface of the steel pipe, and filler is filled in the space between the reinforcing bar and the insulating member, then by appropriately selecting the constituent material of the insulating member and the type of steel pipe, it is possible to substantially eliminate friction between the outer circumferential surface of the insulating member and the inner circumferential surface of the steel pipe, and so the load transmission and blocking effect of the insulating member will be reliably exerted.

[0027] The insulating member may be cylindrical, particularly in the cases of (b) and (c), but particularly in the case of (a), if the sheet material is rolled so that the edges of the sheet material overlap, the insulating member can be expanded in diameter according to the inner diameter of the steel pipe, either naturally by its own restoring force or by the pressure applied when filling the filler material. This prevents the filler from coming into contact with the inner surface of the steel pipe, yet allows the outer surface to be securely abutted against the inner surface of the steel pipe.

[0028] The filler can be made of any material as long as the bending deformation of the reinforcing bars within the steel pipe is substantially restrained by substantially eliminating any play in the reinforcing bars within the steel pipe; however, if the filler is made of a hydraulic material, typically cement paste, and the insulating material is configured so as to prevent water absorption into it, it will be possible to increase the ease of procurement of the filler while preventing a decrease in rigidity or shrinkage of the insulating material due to water absorption, and ultimately to prevent the occurrence of play in the reinforcing bars within the steel pipe.

[0029] A typical example of a specific configuration of insulating material to prevent water absorption inside is when it is made of what is generally called waterproof paper, such as paraffin paper (oil paper), which is made by impregnating kraft paper with paraffin to give it hydrophobic properties. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 shows a diagram of an earthquake-resistant reinforcement structure 11 constructed using the buried steel bar structure of the present invention and a wall-type bridge pier 1 to which it is applied, where (a) is a side view, (b) is a horizontal cross-sectional view along line AA, and (c) is a horizontal cross-sectional view along line BB. [Diagram 2] 1A and 1B are diagrams of earthquake-resistant reinforcement structures, in which (a) is a horizontal cross-sectional view of an earthquake-resistant reinforcement structure 11' according to a conventional configuration, (b) is a horizontal cross-sectional view of an earthquake-resistant reinforcement structure 11, and (c) is a vertical cross-sectional view along line CC. [Diagram 3] 1A and 1B are diagrams showing a reinforcing bar embedded structure 41 according to this embodiment, in which (a) is a vertical cross-sectional view including the material axis, and (b) is a partial perspective view. [Figure 4] 5 is a graph showing the function of the reinforcing bar embedding structure 41 according to the present embodiment. [Diagram 5] 1A and 1B are diagrams of a reinforced concrete structure relating to a modified example, where (a) is a horizontal cross-sectional view and (b) is a vertical cross-sectional view along line DD. [Figure 6] FIG. 13 is a detailed horizontal cross-sectional view of a reinforcing bar embedded structure according to another modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a reinforcing bar embedding structure and method according to the present invention will be described with reference to the accompanying drawings.

[0032] FIG. 1 shows an earthquake-resistant reinforcement structure 11 constructed using the buried steel bar structure of the present invention, and a wall-type pier 1 to which it is applied. As shown in the figure, the earthquake-resistant reinforcement structure 11 is constructed by wrapping a newly constructed RC section 12 around the base 2 of the wall-type pier 1, which is a reinforced concrete column member, as the existing RC section that is the target of earthquake reinforcement.

[0033] The wall-type pier 1 is erected at its base 2 on an RC footing 3 and connected to a superstructure 5 at its top 4, so that vertical and horizontal loads from the superstructure are transmitted to the ground 6 via the RC footing 3.

[0034] The height range of the wall-type pier 1 excluding the base 2, which is representative of the top 4, is wrapped with reinforced concrete 12' to form an earthquake-resistant reinforcement structure 11'.

[0035] FIG. 2 shows an earthquake-resistant reinforcement structure 11' and an earthquake-resistant reinforcement structure 11. As can be seen in FIG. 2(a), the top 4 is made of concrete 21, axial reinforcing bars 22 embedded in the concrete, and shear reinforcement bars 23 surrounding it. The top is wrapped with reinforced concrete 12', which is also made of concrete 24, axial reinforcing bars 25 embedded in the concrete, and shear reinforcement bars 26 surrounding it, to form the earthquake-resistant reinforcement structure 11'. However, since the reinforced concrete 12' is a conventionally known structure, a detailed explanation will be omitted here.

[0036] As shown in Figures 1(b) and 1(c), the earthquake-resistant reinforcement structure 11 is constructed by wrapping a leg 2 consisting of existing concrete 31, existing axial rebar 32 embedded in the existing concrete, and surrounding it with shear reinforcement 33, around which is wrapped a new RC section 12 consisting of new concrete 34, new axial rebar 37 embedded in the new concrete, and surrounding it with shear reinforcement 36, and the existing axial rebar 32 is embedded in the existing concrete 32 while being exposed to the existing concrete.

[0037] On the other hand, the newly-constructed axial reinforcing bars 37 are embedded in the newly-constructed concrete 34, each inserted independently into an individual steel pipe 38. As shown in FIG. 3, a cylindrical insulating member 42 is inserted between the newly-constructed axial reinforcing bars 37 and the steel pipe 38 so that the outer peripheral surface of the insulating member substantially abuts the inner peripheral surface of the steel pipe 38, and the space between the newly-constructed axial reinforcing bars 37 and the insulating member 42 is filled with a filler 43.

[0038] The insulating member 42 is designed to block the compressive load along the axial direction of the newly-installed axial rebar 37 from being transmitted from the peripheral surface of the rebar through the filler material 43 to the inner surface of the steel pipe 38, and together with the newly-installed axial rebar 37, the steel pipe 38 and the filler material 43, constitutes the buried rebar structure 41.

[0039] It is preferable to use a structural steel pipe with no irregularities on its inner and outer surfaces for the steel pipe 38 so that it will not buckle due to compressive forces acting from the newly constructed axial reinforcing bars 37 or from the newly constructed concrete 34 through the filling material 43 and insulating member 42.

[0040] The filler 43 is intended to prevent gaps from occurring between the newly installed axial reinforcing bar 37 and the insulating member 42 in order to effectively utilize the buckling prevention function of the steel pipe 38, and can be made of, for example, cement paste.

[0041] As can be clearly seen in FIG. 3(c), the insulating member 42 is made by rolling a sheet material so that the edges of the sheet material overlap, and can be made of, for example, craft paper.

[0042] To construct the earthquake-resistant reinforcement structure 11 of this embodiment, prior to wrapping the newly constructed RC section 12, unevenness is created in advance on the surface of the leg section 2 by roughening or the like so that the newly constructed RC section will be integrated with the existing RC section, the leg section 2.

[0043] Next, the newly-installed axial rebar 37 is placed around the leg 2, and then a steel pipe 38 is placed over the newly-installed axial rebar. An insulating member 42 is placed between the newly-installed axial rebar 37 and the steel pipe 38 so that the outer surface of the insulating member substantially abuts the inner surface of the steel pipe 38. Next, the space between the newly-installed axial rebar 37 and the insulating member 42 is filled with filling material 43, thereby constructing a rebar embedded structure 41 around the leg 2.

[0044] The insulating member 42 is inserted into the steel pipe 38 by rolling the sheet material so that the edges of the sheet material overlap. If the insulating member is configured so that it exerts a restoring force in the radial expansion direction, it will naturally expand in diameter inside the steel pipe 38 after being inserted into the steel pipe, so that the outer peripheral surface of the insulating member 42 can be reliably abutted against the inner peripheral surface of the steel pipe 38.

[0045] The steel pipes 38 may be arranged together in the concrete pouring area with the newly-installed axial reinforcing bar 37 inserted through them, or with the insulating member 42 further inserted between the newly-installed axial reinforcing bar 37 and the steel pipes 38.

[0046] Next, the shear reinforcement 36 is wound around the newly installed axial reinforcing bar 37, and then concrete is poured in the concrete pouring area.

[0047] As described above, according to the reinforcing bar embedding structure 41 and method of this embodiment, when the newly-installed axial reinforcing bar 37 is inserted into the steel pipe 38 and embedded in the newly-installed concrete 34, a tubular insulating member 42 is placed between the newly-installed axial reinforcing bar 37 and the steel pipe 38 so that the outer surface of the insulating member substantially abuts the inner surface of the steel pipe 38, and the space between the newly-installed axial reinforcing bar 37 and the insulating member 42 is filled with filler material 43.Therefore, even if the filler material 43 filled between the newly-installed axial reinforcing bar 37 and the steel pipe 38 expands laterally due to the Poisson effect, the insulating member 42 blocks the transmission of the compressive load in the axial direction of the newly-installed axial reinforcing bar 37 to the inner surface of the steel pipe 38.

[0048] Therefore, the above-mentioned compressive load does not act on the steel pipe 38, and thus it becomes possible to prevent the steel pipe 38 from buckling.

[0049] In the earthquake-resistant reinforcement structure 11 in which the buried reinforcing bar structure 41 is adopted, the bending deformation of the newly-installed axial reinforcing bars 37 within the length range in which they are inserted into the steel pipe 38 is restrained by the steel pipe 38. This, combined with the buried reinforcing bar structure 41 preventing the steel pipe 38 from buckling itself, reliably prevents the newly-installed axial reinforcing bars 37 from buckling due to axial compressive force.

[0050] Here, the new-construction-side axial rebar 37 is not attached to the new-construction-side concrete 34 in the area where it is inserted into the steel pipe 38, so no load is transmitted between the new-construction-side concrete 34 and the new-construction-side concrete. However, since the new-construction-side concrete 34 is continuously integrated with the existing-construction-side concrete 31, cracks that occur in the new-construction-side concrete 34 are dispersed by the existing-construction-side axial rebar 32, so there is no risk of cracks in the new-construction-side concrete 34 concentrating near the steel pipe 38.

[0051] In this way, the buried reinforcing bar structure 41 prevents the steel pipe 38 from buckling itself, and the steel pipe prevents the buckling of the newly-constructed axial reinforcing bar 37. In addition, the existing axial reinforcing bar 32 suppresses cracking in the newly-constructed concrete 34. This combines to ensure that the newly-constructed RC section 12 absorbs energy through hysteretic damping caused by compression and tension, thereby making it possible to significantly improve the toughness of the wrapped section.

[0052] As a result, there is no longer a need to place intermediate penetrating steel materials, which were previously essential to prevent buckling of the axial reinforcing bars, through the RC column members. As a result, there is no longer any concern about damaging the reinforcing bars embedded in the RC column members when drilling insertion holes for passing the intermediate penetrating steel materials through the existing RC column members, or damaging the RC column members by repeatedly changing the drilling position.

[0053] FIG. 4 shows a reinforced concrete test specimen (test specimen corresponding to the embodiment) that mimics the reinforcing bar embedded structure 41 according to this embodiment, and a reinforced concrete test specimen (comparison test specimen) in which the insulating member is omitted from the above test specimen, and the relationship between the strain generated in the reinforcing bar and the strain generated in the steel pipe was investigated for each.

[0054] From the same figure, it can be seen that in the case of the comparison test specimen (dashed line), as the strain in the reinforcing bar increases, the strain in the steel pipe also increases, and the compressive load is transmitted from the reinforcing bar to the steel pipe, whereas in the case of the test specimen corresponding to the embodiment (solid line), even when the strain in the reinforcing bar increases, almost no strain is generated in the steel pipe, and the compressive load is not transmitted from the reinforcing bar to the steel pipe due to the load transmission blocking action of the insulating member.

[0055] Furthermore, according to the reinforcing bar embedded structure 41 of this embodiment, the insulating member 42 is inserted and positioned so that its outer surface substantially abuts the inner surface of the steel pipe 38, and the filler material 43 is filled in the space between the newly installed axial reinforcing bar 37 and the insulating member 42. Therefore, by making the insulating member 42 from smooth paper such as one-sided glossy kraft paper or coated paper and using a structural steel pipe for the steel pipe 38, it is possible to sufficiently reduce friction between the insulating member 42 and the steel pipe 38, and the load transmission blocking effect of the insulating member 42 can be reliably exerted.

[0056] Furthermore, according to the reinforcing bar embedded structure 41 of this embodiment, the insulating member 42 is formed by rolling the sheet material so that the edges of the sheet material overlap each other. Therefore, the insulating member 42 can be expanded in diameter naturally by its restoring force or by the pressure applied when filling the filler 43 in accordance with the inner diameter of the steel pipe 38. This makes it possible to ensure that the filler 43 does not come into contact with the inner peripheral surface of the steel pipe 38, and yet the outer peripheral surface of the filler 43 can be securely abutted against the inner peripheral surface of the steel pipe 38.

[0057] In this embodiment, the embedded steel bar structure of the present invention is applied to an earthquake-resistant reinforcement structure, i.e., a configuration in which new reinforced concrete is wrapped around existing reinforced concrete, but it can also be applied when constructing a new reinforced concrete structure.

[0058] FIG. 5 shows a reinforced concrete structure relating to the above-mentioned modified example. This reinforced concrete structure is constructed as an RC column member similar to the wall-type pier 1 shown in FIGS. 1 and 2, and is constructed by arranging axial reinforcement bars 51 and axial reinforcement bars 52 alternately at regular intervals, arranging shear reinforcement bars 54 surrounding them, and embedding them in concrete 55.

[0059] Here, the axial reinforcing bars 51 are embedded in the concrete 55 in a state exposed to the concrete, as in the conventional case, but the axial reinforcing bars 52 are embedded in the concrete 55 in a state in which they are each independently inserted into an individual steel pipe 53, and an insulating member (not shown) similar to insulating member 42 is arranged between the axial reinforcing bars 52 and the steel pipe 53 so that the outer surface of the insulating member substantially abuts the inner surface of the steel pipe 53, and the space between the insulating member and the axial reinforcing bars 52 is filled with a filler material (not shown) similar to filler material 43.

[0060] The insulating member is designed to block the transmission of compressive load along the material axis of the axial reinforcing bar 52 from the peripheral surface of the reinforcing bar through the filler material to the inner surface of the steel pipe 53, and together with the axial reinforcing bar 52, the steel pipe 53 and the filler material, constitutes the buried reinforcing bar structure of the present invention.

[0061] Hereinafter, the axial reinforcing bars 52, filler material, insulating members, and steel pipes 53 in this modified example have the same configuration as the newly installed axial reinforcing bars 37, filler material 43, insulating members 42, and steel pipes 38 in the above embodiment, so detailed explanations will be omitted, but this modified example also provides the same effects as the above embodiment.

[0062] In other words, in the buried reinforcing bar structure of this modified example, even if the filler material filled between the axial reinforcing bar 52 and the steel pipe 53 expands laterally due to the Poisson effect, the compressive load in the axial direction of the reinforcing bar 52 is prevented from being transmitted to the inner surface of the steel pipe 53 by the insulating member, and therefore the above-mentioned compressive load does not act on the steel pipe 53, thereby preventing the steel pipe 53 from buckling by itself.

[0063] Furthermore, within the length range of the axial reinforcing bars 52 inserted into the steel pipe 53, their bending deformation is restrained by the steel pipe 53, which, combined with the above-mentioned effect of preventing the steel pipe 53 from buckling itself, reliably prevents the axial reinforcing bars 52 from buckling due to axial compressive force.

[0064] In this modified example, the axial reinforcement bars 51 disperse cracks that occur in the concrete 55, and therefore there is no risk of cracks in the concrete 55 concentrating near the steel pipes 53. This is different from the above embodiment.

[0065] Although not specifically mentioned in this embodiment, the insulating member 42 can be made of what is generally called waterproof paper, including paraffin paper (oil paper), which is made by impregnating kraft paper or the like with paraffin to give it hydrophobicity.

[0066] With this configuration, it is possible to prevent water from being absorbed into the interior, thereby preventing a decrease in rigidity of the insulating member or shrinkage of the insulating member due to water absorption, and ultimately preventing the occurrence of play in the reinforcing bars inside the steel pipe.

[0067] In addition, in this embodiment, the insulating member 42 is inserted and arranged so that its outer circumferential surface substantially abuts the inner circumferential surface of the steel pipe 38, and the filler 43 is filled in the space between the newly installed axial reinforcing bar 37 and the insulating member 42. (a) The barrier effect due to the substantial absence of friction between the outer surface of the insulating member and the inner surface of the steel pipe; and (c) The insulating material is made of a fiber-based material, and therefore the insulating material itself does not have shear resistance, resulting in an interrupting effect. The load transmission blocking action of the insulating member of the present invention utilizes at least one of the above two actions, and instead of the above blocking action, (b) The insulating effect due to the substantial absence of friction between the circumferential surface of the reinforcing bar and the inner circumferential surface of the insulating member; (c) The insulating material is made of a fiber-based material, and therefore the insulating material itself does not have shear resistance, resulting in an interrupting effect. At least one of the above may be used.

[0068] FIG. 6(a) is a detailed cross-sectional view showing such a modified example, in which a cylindrical insulating member 42' is inserted and positioned so that its inner surface substantially abuts the peripheral surface of the newly-installed axial reinforcing bar 37, and a filler material 43 is filled in the space between the insulating member 42' and the steel pipe 38.

[0069] In addition, instead of the load transmission blocking action according to the embodiment, (c) The insulating material is made of a fiber-based material, and therefore the insulating material itself does not have shear resistance, resulting in an interrupting effect. It is possible to use the above configuration.

[0070] FIG. 6(b) is a detailed cross-sectional view showing such a modified example, in which a cylindrical insulating member 42' is inserted between the newly-installed axial reinforcing bar 37 and the steel pipe 38, and a filler material 43 is filled in the space between the newly-installed axial reinforcing bar 37 and the insulating member 42', and in the space between the insulating member 42' and the steel pipe 38.

[0071] In these modified examples, the insulating member 42 in the embodiment is formed by rolling the sheet material so that the edges of the sheet material overlap, whereas the insulating member 42' is formed as a cylinder, which is different from the embodiment. Also, the insertion position of the insulating member 42' differs from that of the insulating member 42. However, other than that, the configuration and effects are generally similar to those of the above-described embodiment, so that description thereof will be omitted here. [Explanation of symbols]

[0072] 34 Newly constructed concrete (concrete) 37 New side axial reinforcing bars (reinforcing bars) 38,53 Steel pipe 41,41´ Reinforced concrete structure 42,42´ Insulating member 43 Filling material 52 Axial reinforcement (reinforcing bars) 55 Concrete

Claims

1. In a reinforcing bar embedded structure in which reinforcing bars are inserted independently into individual steel pipes and embedded in concrete together with the steel pipes, a cylindrical insulating member made of a fibrous material is inserted and positioned between the reinforcing bar and the steel pipe, and a filler is filled in the space between the reinforcing bar and the insulating member with an outer circumferential surface of the insulating member substantially abutting the inner circumferential surface of the steel pipe, a filler is filled in the space between the insulating member and the steel pipe with an inner circumferential surface of the insulating member substantially abutting the outer circumferential surface of the reinforcing bar, or a filler is filled in the space between the reinforcing bar and the insulating member and the space between the insulating member and the steel pipe with the insulating member spaced apart from the inner circumferential surface of the steel pipe and the outer circumferential surface of the reinforcing bar, and the insulating member is adapted to block the transmission of a compressive load along the axial direction of the reinforcing bar from the circumferential surface of the reinforcing bar to the inner circumferential surface of the steel pipe via the filler.

2. 2. A reinforcing bar embedded structure as described in claim 1, wherein the insulating member is inserted and positioned so that its outer peripheral surface substantially abuts the inner peripheral surface of the steel pipe, and the filler is filled in the space between the reinforcing bar and the insulating member.

3. 3. The reinforcing bar embedded structure according to claim 2, wherein the insulating member is formed by rolling the sheet material so that the edges of the sheet material overlap each other.

4. A reinforcing bar embedding method in which reinforcing bars are inserted into individual steel pipes and then the reinforcing bars are placed in a concrete pouring area together with the steel pipes, or reinforcing bars are placed in a concrete pouring area and then the reinforcing bars are covered with individual steel pipes, and then concrete is poured in the concrete pouring area, thereby embedding the reinforcing bars in the concrete together with the steel pipes in a state in which the reinforcing bars are inserted into the steel pipes, A reinforcing bar embedding method comprising inserting and arranging a cylindrical insulating member made of a fiber-based material between the reinforcing bar and the steel pipe so that the outer peripheral surface of the insulating member substantially contacts the inner peripheral surface of the steel pipe, filling a space between the reinforcing bar and the insulating member with a filler, and then pouring concrete into the concrete pouring area, The insulating member is formed by rolling a sheet material so that edges of the sheet material overlap each other, A reinforcing bar embedding method, characterized in that when inserting and placing the insulating member between the reinforcing bar and the steel pipe, the insulating member is expanded in diameter by its restoring force so that the outer surface of the insulating member substantially abuts the inner surface of the steel pipe.

5. 5. The reinforcing bar embedding method according to claim 4, wherein said filler is made of a hydraulic material, and said insulating member is constructed so as to prevent water absorption therein.

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