JP7132406B2 - tube structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to pipe structures, and more particularly to pipe structures such as homogeneous curved pipes and straight pipes.

For example, when burying a tubular body such as a homogeneous curved pipe or a straight pipe in the ground, the tubular body is buried in the concrete body by pouring concrete around the outer circumference of the tubular body for reinforcement against loads such as earth pressure. is known (see Patent Document 1, etc.).

JP-A-2005-121062

The stress state can change suddenly at the boundary between the part of the pipe buried in the concrete and the part protruding from the concrete (that is, near the end face of the concrete). For example, when internal pressure is applied to the tubular body, expansion of the portion of the tubular body buried in the concrete body is almost prevented, while expansion of the portion protruding from the concrete body is allowed. Therefore, the portion of the tubular body near the end surface of the concrete body is likely to be damaged by stress concentration.

In order to solve the above problems, the pipe structure according to the present invention includes:
a tubular body;
a concrete body covering the outer periphery of the tubular body so that the end surface intersects the tubular body;
an annular stress dispersing material provided on the peripheral surface of the tubular body in the vicinity of the end face and dispersing stress generated in the tubular body;
characterized by comprising
According to the present invention, the stress dispersing action of the stress dispersing material can alleviate a sudden change in the state of stress in the tubular body near the end surface of the concrete body. As a result, stress concentration can be suppressed and damage to the tubular body can be prevented.

It is preferable that the stress dispersing material is provided on the outer peripheral surface of the tubular body.
By providing the stress dispersing material on the outer peripheral surface of the tubular body instead of the inner peripheral surface, it is possible to avoid a reduction in the cross-sectional area of the inner space of the tubular body.

The stress dispersing member includes a deformation restraining member that protrudes from the end face to the outside of the concrete body along the tubular body and restrains deformation of the tubular body, and the deformation restraining force of the deformation restraining member is applied to the concrete body. is preferably lower than the deformation constraint force of
As a result, deformation of the portion of the tubular body covered by the concrete body is suppressed or prevented. The deformation of the portion of the tubular body provided with the deformation restricting member is suppressed by a weaker force than the portion covered by the concrete body. Deformation is allowed in a portion of the tubular body outside the deformation restricting member. As a result, sudden changes in the stress state of the tubular body can be reliably alleviated, and the stress can be reliably dispersed.

It is preferable that the deformation restraint includes fiber-reinforced plastic.
As a result, it is possible to reliably develop a deformation restraining force on the tubular body.

It is preferable that the thickness of the deformation restricting member decreases with increasing distance from the end surface.
As a result, the deformation constraint force can be decreased as the distance from the end face of the concrete body increases, and the sudden change in the stress state can be reliably alleviated.

The stress dispersing member may include a deformation-allowing member that extends along the tubular body from the end face toward the inner side of the concrete body and allows deformation of the tubular body.
As a result, deformation is suppressed or prevented in the portion of the concrete body on the far side of the deformation-allowing material in the tubular body. The portion of the tubular body provided with the deformation-allowing material is allowed to deform by the deformation-allowable amount of the deformation-allowing material. Deformation of the portion of the pipe protruding from the concrete body is sufficiently permitted. As a result, sudden changes in the stress state of the tubular body can be reliably alleviated, and the stress can be reliably dispersed.

It is preferable that the deformation-allowing material includes an elastic material.
As a result, the portion of the tubular body provided with the deformation-allowing material can be allowed to deform by the elastically deformable amount of the deformation-allowing material.

It is preferable that the thickness of the deformation-allowing material decreases from the end face toward the inner side of the concrete body.
As a result, the deformation tolerance can be increased as the concrete body approaches the end face from the deep side, and a sudden change in the stress state can be reliably alleviated.

The pipe structure according to the present invention is suitable for homogeneous bent pipes. That is, the tubular structure includes the tubular body and an outer surface connecting member, the tubular body includes a plurality of unit tubes, each unit tube having an inclined end surface oblique to its own axis, It is preferable that the inclined end faces of adjacent unit pipes abut against each other, and the outer surface connecting member straddles between the outer peripheral surfaces of the adjacent unit pipes to connect these unit pipes.
In the pipe structure made of the homogeneous curved pipe, the deformation restraint member is configured by an outer surface connecting member in the concrete body that is in the immediate vicinity of the end face and extends to the outside of the end face along the pipe body. is preferred.
This makes it possible to efficiently construct the outer surface connecting member and the deformation restraining member in the homogeneous curved pipe.
In addition, the pipe structure according to the present invention is not limited to the bent pipe structure such as the homogenous bent pipe, and may be a straight pipe structure.

ADVANTAGE OF THE INVENTION According to this invention, the sudden change of the stress state in the end surface vicinity of the concrete body in a tubular body can be relieved, and damage to a tubular body can be prevented.

FIG. 1 is a plan view showing a main part of a pipe structure according to a first embodiment of the present invention, with a protective concrete (concrete body) sectioned. 2 is a cross-sectional view of circle II of FIG. 1; FIG. FIG. 3 shows a modification of the first embodiment, and is a cross-sectional view corresponding to FIG. FIG. 4 shows another modification of the first embodiment, and is a sectional view corresponding to FIG. FIG. 5 shows another modification of the first embodiment, and is a plan view corresponding to FIG. FIG. 6 is a cross-sectional view of circle VI of FIG. FIG. 7 is a plan view showing the main part of the pipe structure according to the second embodiment of the present invention, with a concrete body in cross section. 8 is a cross-sectional view of circle VIII of FIG. 7. FIG. FIG. 9 is a plan view showing the main part of the pipe structure according to the third embodiment of the present invention, with a concrete body in cross section. 10 is a cross-sectional view of circle portion X of FIG. 9. FIG. FIG. 11 shows a modification of the third embodiment, and is a sectional view corresponding to FIG. FIG. 12 shows another modification of the third embodiment, and is a cross-sectional view corresponding to FIG. FIG. 13 shows another modification of the third embodiment, and is a plan view corresponding to FIG. 14 is a cross-sectional view along line XIV-XIV in FIG. 13. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.
<First embodiment>
1 and 2 show a first embodiment of the invention. As shown in FIG. 1, a pipe structure 1 is provided, for example, as a sewage pipe, an agricultural water pipe, or the like. The pipe structure 1 comprises a homogeneous curved pipe 2 and protective concrete 3 (concrete body). The homogeneous curved pipe 2 is obtained by obliquely cutting a raw material pipe, for example, to obtain a plurality of unit pipes 11, and one unit pipe 11 of two adjacent unit pipes 11 is rotated 180° with respect to the other unit pipe 11. After that, the cut end faces are abutted against each other and connected. Thereby, the tube axis of the homogeneous bent tube 2 is bent by a predetermined angle (for example, 90°).

Specifically, the homogeneous bent pipe 2 has a bent pipe body 10 (pipe body) and an outer surface connecting member 20 . The curved pipe body 10 includes multiple unit pipes 11 . A plurality of unit tubes 11 are arranged in a row. At least one end face 11 e of each unit pipe 11 is inclined with respect to the axis of the unit pipe 11 . The oblique end faces 11e of adjacent unit pipes 11 are abutted against each other to be connected.

One end (the upper end in FIG. 1) of the curved pipe body 10 has an outer circumference that is enlarged to form a socket 2a. The other end of the curved pipe body 10 (right end in FIG. 1) serves as a spigot 2b. A bent portion 2c is formed between the socket 2a and the insert 2b. A spigot for another tube (not shown) is inserted into the socket 2a. The spigot 2b is inserted into a socket of another tube (not shown).
The receptacle 2a of the bent pipe body 10 may have a structure in which the outer circumference is thinned without being expanded in diameter to receive the receptacle 2b. Alternatively, a structure may be adopted in which a collar serving as the socket 2a is provided at one end of the bent pipe body 10 and slightly enlarged in diameter to receive the socket 2b.

Each unit pipe 11 and thus the curved pipe body 10 is composed of a hard resin pipe such as a fiber reinforced plastic pipe (FRP pipe) or a fiber reinforced plastic composite pipe (FRPM pipe). FRP pipes and FRPM pipes may be produced by a filament winding molding method.

Outer surface connecting members 20 are arranged between adjacent unit pipes 11 in the curved pipe body 10 . The outer surface connecting member 20 is made of fiber reinforced plastic (FRP). Specifically, as shown in FIG. 2 , the outer surface connecting member 20 includes a cloth-like body 21 (reinforcing fiber) and a filling resin 22 . Examples of the material of the cloth-like body 21 include glass fiber, carbon fiber, aramid fiber, and the like. The cloth-like body 21 may be a woven cloth such as a roving cloth, or may be a nonwoven fabric (a non-directional cloth-like body) such as a glass mat. The cloth-like body 21 in FIG. 2 is schematically illustrated for convenience of drawing. The filling resin 22 is impregnated into the cloth-like body 21 . Components of the filling resin 22 include unsaturated polyester resins, epoxy resins, vinyl ester resins, and the like.

As shown in FIG. 1, the outer surface connecting member 20 straddles between the outer peripheral surfaces of the adjacent unit pipes 11, and the filling resin 22, which is annularly wound in the circumferential direction of each unit pipe 11, is applied or applied. It is adhered to the curved pipe body 10 due to its adhesiveness when uncured. Adjacent unit pipes 11 are connected to each other via outer surface connecting members 20 . Adjacent outer surface connecting members 20 are separated from each other in the outer peripheral portion 2o of the homogeneous curved pipe 2. As shown in FIG. In the inner peripheral portion 2i of the homogeneous bent pipe 2, the adjacent outer surface connecting members 20 are slightly overlapped or connected to each other. Adjacent outer surface connecting members 20 may be separated from each other in the inner peripheral portion 2i as well.

The thickness of the outer connecting member 20 or the number of layers of the cloth-like body 21 is set according to the required pressure resistance of the homogeneous curved pipe 2 and the like. The required pressure resistance (internal pressure) of the homogeneous curved pipe 2 is, for example, about 0.5 MPa. If higher pressure resistance is required, it can be met by increasing the number of layers of the cloth-like body 21 .

Although detailed illustration is omitted, the homogeneous bent pipe 2 is laid underground. As shown in FIG. 1, protective concrete 3 is placed around the bend 2c for reinforcement against loads such as earth pressure. As a result, the protective concrete 3 covers the outer periphery of the bent portion 2c. In other words, the bent portion 2c is embedded in the protective concrete 3. The socket 2a and the spigot 2b protrude from the protective concrete 3, respectively. Two end faces 3e of the protective concrete 3 intersect the homogeneous bent pipe 2. As shown in FIG. The protective concrete 3 may be reinforced concrete or a concrete body without reinforcing bars.

As shown in FIG. 1, a deformation restricting member 30 (stress dispersing member) is provided in a portion of the homogeneous bent pipe 2 near the end face 3e. The deformation restricting member 30 is made of fiber reinforced plastic (FRP). Specifically, as shown in FIG. 3B, the deformation restraint member 30 includes a cloth-like body 31 (reinforcing fiber) and a filling resin 32 . Examples of the material of the cloth-like body 31 include glass fiber, carbon fiber, aramid fiber, and the like. The cloth-like body 31 may be a woven cloth such as a roving cloth, or may be a nonwoven fabric (a non-directional cloth-like body) such as a glass mat. The cloth-like body 31 in FIG. 2 is schematically illustrated for convenience of drawing. The filling resin 32 is impregnated into the cloth-like body 31 . Components of the filling resin 32 include unsaturated polyester resins, epoxy resins, vinyl ester resins, and the like.

As shown in FIG. 2, the deformation restricting member 30 protrudes from the end face 3e along the curved tubular body 10. As shown in FIG. The deformation restraint member 30 is annular so as to surround the outer peripheral surface of the curved tubular body 10 . The filling resin 32 of the deformation restricting material 30 is adhered to the curved pipe body 10 by adhesiveness at the time of application or at the time of uncuring. A portion of the deformation restraint member 30 on the side of the protective concrete 3 (left side in FIG. 2) slightly enters the protective concrete 3 . The width W30e of the portion _30e of the deformation restricting member 30 overhanging the protective concrete 3 is sufficiently larger than the width W30d of the portion _30d of the deformation restricting member 30 embedded in the protective concrete 3 ( _W30e > _W30d ). For example, the width W _30e of the projecting portion 30e is W _30e =several cm to several tens of cm, preferably W _30e =about 5 cm to 30 cm. The width W _30d of the embedded portion 30d is W _30d =several mm to several cm, preferably W _30d =about 5 mm.

The deformation restraint member 30 is separated from the nearest outer surface connecting member 20 . In particular, the deformation restricting member 30 is separated from the outer surface connecting member 20 also in the inner peripheral portion 2i of the homogeneous curved pipe 2. As shown in FIG. In addition, in the inner peripheral portion 2i, the deformation restricting member 30 and the outer surface connecting member 20 may be overlapped or connected.

In the pipe structure 1 configured as described above, the homogenous curved pipe 2 is subjected to internal water pressure of, for example, about 0.5 MPa at maximum. Alternatively, it is also assumed that a higher internal water pressure is applied. Since the bent portion 2c is constrained by the protective concrete 3 against such high internal water pressure, expansion deformation is almost prevented. On the other hand, the socket 2a and the spigot 2b outside the deformation restraining member 30 are not restrained by the protective concrete 3 and are not restrained by the deformation restraining member 30, which will be described later, so expansion deformation is allowed.
A portion of the curved pipe body 10 provided with the deformation restricting member 30 is restrained by the deformation restricting member 30, and expansion deformation is suppressed. The deformation restraint force by the deformation restraint member 30 is lower than the deformation restraint force by the protective concrete 3 . As a result, a sudden change in the stress state of the bent tube body 10 near the end surface 3e can be alleviated, and the stress can be dispersed. By providing the embedded portion 30d so that the deformation restraint member 30 straddles the end face 3e of the protective concrete 3, the discontinuity of the stress state on the end face 3e of the curved pipe body 10 can be reliably alleviated. As a result, stress concentration can be suppressed, and damage to the curved pipe body 10 can be prevented.
Furthermore, the deformation restraint member 30 can increase the resistance to the shear stress that occurs when the protective concrete 3 subsides unevenly.
By providing the deformation restricting member 30 not on the inner peripheral surface of the curved pipe body 10 but on the outer peripheral surface, it is possible to avoid the loss of the cross-sectional area of the homogeneous curved pipe 2 and thus the conductance.

Next, another embodiment of the present invention will be described. In the following embodiments, the same reference numerals are given to the drawings to duplicate the configurations already described, and the description thereof is omitted.
FIG. 3 relates to a modification of the first embodiment. The deformation restricting member 30 in this modification does not have the embedded portion 30d. The entire deformation restraining member 30 is arranged outside the protective concrete 3 . An end surface of the deformation restraint member 30 facing the protective concrete 3 is in contact with the end surface 3e.

FIG. 4 relates to another modification of the first embodiment. The deformation restricting member 30 in this modified mode has a thickness that decreases with increasing distance from the end face 3e. Thereby, the deformation restraining force can be gradually reduced as the distance from the end face 3e increases. Therefore, the discontinuity of the stress state can be relieved reliably. In particular, it is possible to alleviate a sudden change in the state of stress at the tip of the deformation restricting member 30 (the end on the side opposite to the end surface 3e).

5 and 6 relate to another modification of the first embodiment. In this modified form, the outer surface connecting member 20E in the protective concrete 3 in the immediate vicinity of the end face 3e is continuous with the deformation restricting member 30. As shown in FIG. Specifically, the outer surface connecting member 20E covers the entire outer peripheral surface of the curved tubular body 10 from the connection portion between the unit tubes 11 in the immediate vicinity of the end surface 3e to the end surface 3e, and further extends along the curved tubular body 10. It extends out of 3e. A portion of the outer surface connecting member 20E extending from the end face 3e constitutes a deformation restricting member 30 (stress dispersion member). Therefore, the deformation restricting member 30 is integrated with the outer surface connecting member 20E.
According to this modification, the deformation restricting member 30 can also be manufactured at the same time by manufacturing the outer surface connecting member 20E. As a result, the construction of the outer surface connecting member 20E and the deformation restraining member 30 can be made more efficient, and the construction of the homogeneous curved pipe 2 can be made more efficient.

<Second embodiment>
7 and 8 show a second embodiment of the invention. As shown in FIG. 7, in the tubular structure 1B, the tubular body 10S is composed of a straight tube. The straight pipe body 10S is composed of a hard resin pipe such as a fiber reinforced plastic pipe (FRP pipe) or a fiber reinforced plastic composite pipe (FRPM pipe). FRP pipes and FRPM pipes may be produced by a filament winding molding method.

The straight pipe body 10S is partially embedded in the concrete body 3B. The concrete body 3B may be made of reinforced concrete, or may be made of concrete that does not contain reinforcing bars. The straight pipe body 10S extends out from the end surface 3e of the concrete body 3B.

As shown in FIG. 8, a deformation restricting member 30 made of fiber reinforced plastic (FRP) is provided in the vicinity of the end surface 3e of the straight tube 10S. As in the first embodiment (FIG. 2), the deformation restricting member 30 slightly enters the concrete body 3B and protrudes from the end surface 3e along the straight pipe body 10S. The width W _30e of the portion 30e of the deformation restricting member 30 overhanging the concrete body 3B is sufficiently larger than the width W _30d of the portion 30d of the deformation restricting member 30 embedded in the concrete body 3B (W _30e >W _30d ). . For example, the width W _30e of the projecting portion 30e is W _30e =several cm to several tens of cm, preferably W _30e =about 5 cm to 30 cm. The width W _30d of the embedded portion 30d is W _30d =several mm to several cm, preferably W _30d =about 5 mm.

According to the second embodiment, when the internal water pressure acts on the straight pipe 10S, the straight pipe 10S in the concrete body 3B is restrained by the concrete body 3B, so expansion deformation is almost prevented. On the other hand, the straight pipe 10S outside the deformation restricting member 30 outside the concrete body 3B (on the right side in FIG. 8) is not restricted by the concrete body 3B and is not restricted by the deformation restricting member 30 described later, so it expands. Deformation is allowed.
A portion of the straight tube 10S provided with the deformation restricting member 30 is restrained by the deformation restricting member 30, and expansion deformation is suppressed. The deformation restraint force by the deformation restraint member 30 is lower than the deformation restraint force by the concrete body 3B. As a result, a sudden change in the stress state of the straight tubular body 10S in the vicinity of the end surface 3e can be alleviated and the stress can be dispersed. As a result, stress concentration can be suppressed and damage to the straight pipe body 10S can be prevented.

As a modification of the second embodiment, the deformation restricting member 30 may be composed of only the overhanging portion 30e and may not include the embedded portion 30d, as in the modification of FIG. The thickness of the deformation restricting member 30 may decrease as the distance from the end face 3e increases, as in the deformation mode of FIG.

<Third Embodiment>
9 and 10 show a third embodiment of the invention. As shown in FIG. 9, in the tubular structure 1C, a deformation-allowing material 40 (stress dispersing material) is provided near the end surface 3e of the straight tubular body 10S. The deformation-allowing material 40 is made of an elastic material. The material of the elastic body preferably has a lower elastic modulus (higher flexibility) than the FRP constituting the straight pipe body 10S. rubber, etc.) and foamed plastics.

A deformation-allowing material 40 is interposed between the concrete body 3B and the straight pipe body 10S. The deformation-allowing member 40 is annular so as to surround the outer periphery of the straight pipe body 10S in the concrete body 3B. The deformation-allowing member 40 extends from the end face 3e to the far side (left side in FIG. 10) of the concrete body 3B. The end surface of the deformation-permitting member 40 facing the outside of the concrete body 3B and the end surface 3e are flush with each other. The width W ₄₀ of the deformation-permitting member 40 along the axis of the straight tubular body 10S is W ₄₀ =several cm to several tens of cm, preferably W ₄₀ =about 5 cm to 15 cm.

According to the third embodiment, when internal water pressure acts on the straight pipe body 10S, the straight pipe body 10S on the far side (left side in FIG. 10) of the deformation-allowing member 40 in the concrete body 3B is pushed by the concrete body 3B. Due to the restraint, expansion deformation is mostly prevented. On the other hand, the straight pipe body 10S outside the concrete body 3B is not restrained by the concrete body 3B, so expansion deformation is allowed.
The portion of the straight pipe body 10S in the concrete body 3B provided with the deformation-allowing material 40 is allowed to expand and deform by the amount that the deformation-allowing material 40 can compress. The tolerance for expansion deformation of the straight pipe body 10S due to the compression of the deformation-allowing material 40 is smaller than the tolerance for expansion deformation outside the concrete body 3B. As a result, a sudden change in the stress state of the straight tubular body 10S in the vicinity of the end surface 3e can be alleviated and the stress can be dispersed. As a result, stress concentration can be suppressed and damage to the straight pipe body 10S can be prevented.

FIG. 11 relates to a modification of the third embodiment. In this modified form, the end portion of the deformation-permitting member 40 facing the outside of the concrete body 3B protrudes slightly from the end surface 3e.

FIG. 12 relates to another modification of the third embodiment. In this modified form, the thickness of the deformation-permitting member 40 decreases from the end surface 3e toward the inner side (left side in FIG. 12) of the concrete body 3B. As a result, the allowable degree of expansion deformation can be gradually increased as the concrete body 3B approaches the end surface 3e from the inner side thereof. Therefore, the discontinuity of the stress state can be relieved reliably. In particular, it is possible to alleviate a sudden change in the state of stress at the far side (left side in FIG. 12) end of the deformation-allowing member 40 .

13 and 14 relate to another modification of the third embodiment. In this modification, the deformation-allowing material 40 is provided over the entire length of the straight pipe body 10S in the concrete body 3B. Furthermore, the end portion of the deformation-allowing material 40 protrudes slightly from the end surface 3e. In addition, the end portion of the deformation-allowing member 40 may be flush with the end surface 3e. Also in this modified mode, the stress can be dispersed by alleviating a sudden change in the state of stress in the straight tube 10S.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention.
For example, a stress dispersion material such as the deformation restraint material 30 may be provided on the inner peripheral surface of the tubular body. The material of the deformation restricting member 30 is not limited to fiber reinforced plastic, and may be rubber or the like similar to that of the deformation permitting member 40 .
You may combine 1st Embodiment and 3rd Embodiment. That is, instead of the deformation restraint member 30 as the stress dispersing material of the homogeneous curved pipe 2 in the first embodiment (FIGS. 1 to 2) or its modification mode (FIGS. 3 to 6), the third embodiment (FIG. 9 10) or modified forms thereof (FIGS. 11 to 14) may be applied.

The present invention can be applied, for example, to sewage pipes and agricultural water pipes.

1, 1B, 1C Pipe structure 2 Homogeneous bent pipe 2a Socket 2b Insertion 2c Bent portion 2i Inner circumference portion 2o Outer circumference portion 3 Protective concrete (concrete body)
3B Concrete body 3e End surface 10 Curved pipe (pipe)
10S straight tube (pipe)
10e Gap 11 Unit pipe 11e Inclined end surface 20 External surface connecting member 20E External surface connecting member 21 near the end surface of the concrete body Cloth-like body 22 Filling resin 30 Deformation restraining material (stress dispersion material)
30e Projecting portion 30d Embedding portion 31 Cloth-like body 32 Filling resin 40 Deformation-allowing material (stress dispersing material)

Claims (2)

a homogenous bent pipe including a pipe body and an outer surface connecting member;
a concrete body covering the outer periphery of the tubular body so that the end surface intersects the tubular body;
an annular stress dispersing material provided on the peripheral surface of the tubular body in the vicinity of the end face and dispersing stress generated in the tubular body;
wherein the tubular body includes a plurality of unit tubes, each unit tube having an inclined end surface oblique to its own axis, and the inclined end surfaces of adjacent unit tubes are abutted against each other;
The outer surface connecting member straddles between the outer peripheral surfaces of adjacent unit pipes to connect these unit pipes,
The outer surface connecting member in the concrete body in the immediate vicinity of the end face is made of fiber-reinforced plastic bonded to the tubular body, and extends out of the end face along the tubular body, so that the stress dispersion member A tubular structure comprising: a homogenous bent pipe including a pipe body and an outer surface connecting member;
a concrete body having two end surfaces intersecting with both ends of the tubular body and covering the outer periphery of the tubular body;
an annular stress dispersing material provided on the peripheral surface of the tubular body in the vicinity of the end face and dispersing stress generated in the tubular body;
wherein the tubular body includes a plurality of unit pipes, each unit pipe having an inclined end surface oblique to its own axis, and the inclined end surfaces of adjacent unit pipes are abutted against each other to connect the outer surface The material straddles the outer peripheral surfaces of adjacent unit pipes and connects these unit pipes,
One end of the tubular body protrudes from one of the two end faces of the concrete body and serves as a socket into which another pipe is inserted, and the other end of the tubular body is the concrete body. A socket protruding from the other of the two end faces and inserted into a socket of another tube,
The stress dispersing member includes a deformation restraining member provided in the socket of the tubular body and a deformation restraining member provided in the spigot of the tubular body, and each of the deformation constraining members of the socket and the spigot A pipe structure comprising a fiber-reinforced plastic bonded to said pipe, projecting along said pipe to the outside of said concrete body and partially embedded in said concrete body. .

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