JP4362981B2 - Connection structure of steel pipe and steel pipe pile - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a steel pipe connection structure, and more particularly to a steel pipe pile connection structure used as a foundation pile or an anchor for structures such as civil engineering and construction.
[0002]
[Prior art]
Steel pipes have limitations on the length of steel pipes due to restrictions on manufacturing equipment and transportation. Therefore, steel pipe piles used as foundation piles for structures such as civil engineering and construction are not suitable. There are many cases where two or more steel pipe piles are connected in the length direction at the site buried in the ground.
[0003]
Conventionally, as shown in FIG. 5, the connection structure of steel pipe piles is such that the ends of two steel pipes 30 and 60 provided with grooves are brought into contact with each other, and a core ring 40 is disposed on the inner surface of the welded portion. A structure for connecting by a welded joint 50 has been known.
When connecting steel pipe piles 30 and 40 with such joints (circumferential welds) 50, it takes a long time to perform welding on-site, which may interfere with other operations or obtain good welding results. Had the disadvantage of requiring skilled skills.
[0004]
Therefore, as a steel pipe pile connection structure that eliminates these disadvantages, a male thread portion screwed on one outer peripheral surface of one pile body and an inner peripheral surface of the other end of the other pile main body were screwed. A connection structure has been proposed in which a female screw part is screwed to form a connection part.
For example, in Japanese Patent Application Laid-Open No. Hei 6-93054, as shown in FIGS. 6 (a) and 6 (b), steel pipe piles 30 and 60 are screwed together and connected in the length direction by a connecting portion 100. A connection structure has been proposed.
[0005]
However, in the connection portion 100 proposed in Japanese Patent Laid-Open No. 6-93054, when a certain amount of bending moment M acts on the ground, the connection portion 100 is plastically deformed so that one screw thread becomes the other screw thread. There was a problem that a mountain crossing that would exceed the limit could occur and the screw would come off.
Moreover, what connected the threaded coupling manufactured separately from the pile main body to the pile main body edge as a connection structure of a steel pipe pile is known.
[0006]
For example, Japanese Patent Laid-Open No. 10-8458 proposes steel pipe piles 600 and 700 formed by attaching threaded joints 200 and 300 to pile bodies 400 and 500 as shown in FIG.
However, in order to produce the joints 200 and 300 as shown in FIG. 7, a thick steel pipe is required separately, and there is a problem that the structural cost for manufacturing the thick steel pipe increases.
[0007]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to eliminate the problems in the connection part of the steel pipe and steel pipe pile according to the prior art, and the steel pipe and steel pipe pile having high bending strength at the connection part can be easily connected. It is to provide a connection structure.
[0008]
[Means for Solving the Problems]
The present invention relates to a steel pipe connection structure in which one steel pipe and the other steel pipe are connected in the length direction. The other steel pipe is circumferentially formed on one end of the main body, a male thread portion screwed on the outer surface, and an inner surface. An inner surface reinforcing member joined along the inner surface, and the other steel pipe has a female thread portion screwed on the inner surface at one end of the main body and an outer surface reinforcing member joined along the circumferential direction to the outer surface, The steel pipe connection structure is characterized in that the one steel pipe and the other steel pipe are connected by a screw connection between the male screw part and the female screw part.
[0009]
In the present invention, it is preferable that the inner surface reinforcing member and the outer surface reinforcing member are joined to each steel pipe body by an adhesive.
Moreover, this invention is the connection structure of the said steel pipe, The connection structure of the steel pipe pile characterized by a steel pipe being a steel pipe pile.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The connection structure of the steel pipe of the present invention will be described in detail with reference to FIGS. 1 to 3 by taking as an example the case where the steel pipe is a steel pipe pile.
Fig.1 (a) and FIG.1 (b) are partial longitudinal cross-sectional views which show the state before and after the connection of the steel pipe pile which concerns on embodiment of this invention.
[0011]
Moreover, FIG. 2 is principal part sectional drawing of the steel pipe pile which concerns on embodiment of this invention, FIG. 3 is a fragmentary sectional view which shows the joining state of the reinforcement member used for this invention.
1 and 2, 1 is a male thread part, 4 is a female thread part, 2 is an inner surface reinforcing member, 5 is an outer surface reinforcing member, 3, 6 is a pile body, 7, 8 are steel pipe piles, and 10 is a connection part. is there.
Here, the connection part 10 shown in FIG. 1 (b) and FIG. 2 is a screw coupling part with the male screw part 1 and the female screw part 4, L shown in FIG. 2 is the length of the connection part, D is the outer diameter of the pile body, d is the inner diameter of the pile body.
[0012]
The male thread portion 1 is screwed on the outer surface of the pile body 3 over a range of a length L from one tip of the pile body 3. The female thread portion 4 is screwed on the inner surface of the pile body 6 over a range of a length L from one tip of the pile body 6.
And one steel pipe pile 7 which has the said external thread part 1 has the inner surface reinforcement member 2 joined along the circumferential direction to the inner surface of the edge part by which the external thread part 1 of the pile main body 3 is screwed. The other steel pipe pile 8 having the female thread portion 4 has an outer surface reinforcing member 5 joined along the circumferential direction to the outer surface of the pile body 6 on which the male thread portion 4 is screwed. .
[0013]
Thus, the steel pipe pile which concerns on the form of the Example of this invention is the connection structure of the steel pipe pile which connects one steel pipe pile 7 and the other steel pipe pile 8 to a length direction, and the steel pipe pile 7 is a pile main body. 3 has a male thread portion 1 screwed on the outer surface and an inner surface reinforcing member 2 joined to the inner surface along the circumferential direction, and a steel pipe pile 8 is threaded on one end portion of the pile body 6 and on the inner surface. A steel pipe pile 7 and a steel pipe pile having a female threaded portion 4 and an outer surface reinforcing member 5 joined to the outer surface of the other end portion along the circumferential direction. 8 is configured to be connected.
[0014]
In addition, in the case of the steel pipe piles 7 and 8 which concern on embodiment shown in FIG. 1, FIG. 2, joining of the inner surface reinforcement member 2 and the pile main body 3, and joining of the outer surface reinforcement member 5 and the pile main body 6 are an adhesive agent. In this case, the entire contact surface is joined.
Moreover, as the inner surface reinforcing member 2 and the outer surface reinforcing member 5, for example, a steel material or a steel plate can be used, and a steel band is preferable in terms of strength, cost, and the like.
[0015]
Here, the thickness t ₂ of the inner surface reinforcing member 2 and the outer surface reinforcing member 5 when the axial tensile strength at the ends of the steel pipe piles 7 and 8 after reinforcement is equal to or higher than the axial tensile strength of the pile main bodies 3 and 6 and The yield point σ ₂ may satisfy the formula (1).
t ₀ × σ ₁ ≦ (t ₁ × σ ₁ + t ₂ × σ ₂ ) (1)
Here, t ₀ is the thickness of the center of the pile body, t ₁ is the tip thickness of the pile body, and σ ₁ is the yield point of the pile body. Here, it goes without saying that the thickness of the inner surface reinforcing member 2 and the thickness of the outer surface reinforcing member 5 do not have to be the same.
[0016]
In the steel pipe piles 7 and 8 according to this embodiment, the inner surface reinforcing member 2 and the outer surface reinforcing member 5 are pile main bodies 3 and 6 in which the male screw portion 1 and the female screw portion 4 are respectively screwed to reduce the thickness. However, the present invention is not limited to this, and the pile main body 3 in which the inner surface reinforcing member 2 and the outer surface reinforcing member 5 are reduced in thickness. , 6 may be joined to a partial range of the lengthwise section of the inner surface or the outer surface, respectively.
[0017]
For example, FIGS. 3B and 3C show a case where the inner surface reinforcing member 2 is joined to a partial range of the lengthwise section of the inner surface at the end of the pile body 3.
In addition, 11 shown to Fig.3 (a)-(c) is a junction part, and joining of the outer surface reinforcement member 5 and the pile main body 6 which are not shown in figure is also the same junction part.
Here, when joining the inner surface reinforcement member 2 and the outer surface reinforcement member 5 to the pile main bodies 3 and 6, respectively, it is preferable to join them with an adhesive.
[0018]
The reason for this is that according to the bonding with the adhesive, the inner surface reinforcing member 2 and the outer surface reinforcing member 5 can be bonded to the pile main bodies 3 and 6 on the entire contact surface, respectively, so that the bending strength is effectively increased. Because you can.
In the case of a steel pipe pile that is buried in the ground and receives a bending force or the like, it is desirable to use an epoxy resin or an acrylic resin as the adhesive.
[0019]
In addition, in this invention, as shown in FIG.3 (c), between the upper-lower-end surface of the reinforcement member 2 and the inner surface of the pile main body 3 can also be welded and joined along the circumferential direction. The same applies to the end surface of the reinforcing member 5 (not shown) and the outer surface of the pile body 6.
As described above, since the steel pipe pile of the present invention is configured to be connected by screw connection, when embedding the steel pipe pile on the ground, one steel pipe pile and the other steel pipe pile are easily connected. As part of or the entire lengthwise section of the end of the pile body that is thin can be reinforced with a reinforcing member, the screw at the connecting portion can be removed as compared to the case without reinforcement. The bending strength up to can be increased.
[0020]
Furthermore, since the male screw portion 1 and the female screw portion 4 are directly screwed to the pile main bodies 3 and 4 and a steel hand can be used for the inner surface reinforcing member 2 and the outer surface reinforcing member 5, a threaded joint is used. The manufacturing cost is lower than when it is attached to the main bodies 3 and 4. It is also possible to increase the bending strength until the screw at the connecting portion is removed up to the bending strength of the pile body.
[0021]
Even when the steel pipe pile described above is a steel pipe, as in the case of the steel pipe pile, since it is configured to be connected by screw connection, it can be easily connected and the pile body that is thin Since part or all of the lengthwise section of the end portion is reinforced by the reinforcing member, the bending strength at the connecting portion can be increased.
[0022]
【Example】
For steel pipe piles (steel grade: SKK400, yield point σ ₁ : 235 MPa) with an outer diameter D of 600 mm and a thickness t ₀ of 16 mm, with or without reinforcement as shown in FIGS. A bending test was performed for comparison. In addition, the tip thickness t ₁ of the pile body is 7 mm, the connecting portion length L is 100 mm, and the inner surface reinforcing material and the outer surface reinforcing material are each made of steel having a length t ₂ of 12 mm and a width of 150 mm (steel type: SM490, yield point σ ₂ : 325 MPa) A reinforcing band was used. The test results are shown in FIG.
[0023]
Fig.4 (a) is the graph which compared the bending strength of the steel pipe pile of an Example with the case without reinforcement, FIG.4 (b) is the schematic of a test method.
In the embodiment in which the reinforcement as shown in FIGS. 1 and 2 is applied, the bending strength until the screw is removed at the connecting portion is improved as compared with the case without the reinforcement. In FIG. 4A, the mark ● represents the yield strength of the pile body. The reinforcing members were joined by fillet welding at the ends of the reinforcing members.
[0024]
【The invention's effect】
According to the structure of the steel pipe and the steel pipe pile of the present invention, the steel pipes or the steel pipe piles can be easily connected to each other, and the bending strength at the connection portion can be increased.
[Brief description of the drawings]
FIG. 1 is a partial longitudinal sectional view showing a state before and after connection of steel pipe piles according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a main part of a steel pipe pile according to an embodiment of the present invention.
FIG. 3 is a partial cross-sectional view showing a joined state of a reinforcing member used in the present invention.
FIG. 4A is a graph comparing the bending strength of a steel pipe pile of an example with that of a steel pipe pile without reinforcement, and FIG. 4B is a schematic diagram of a test method.
FIG. 5 is a longitudinal sectional view of a main part of a conventional steel pipe pile.
FIG. 6 is a partial longitudinal sectional view of another conventional steel pipe pile.
FIG. 7 is a longitudinal sectional view of a main part of another conventional steel pipe pile.
[Explanation of symbols]
1, 4 Thread part 2, 5 Reinforcement member 3, 6 Pile body 7, 8 Steel pipe pile
10 Connection
11 Junction L Connection length t ₀ Pile body center thickness t ₁ Pile body tip thickness t ₂ Reinforcement member thickness σ ₁ Pile body yield point σ ₂ Reinforcement member yield point D Pile body outer diameter d Pile Inner diameter of main body

Claims (3)

In the steel pipe connection structure that connects one steel pipe and the other steel pipe in the length direction,
The one steel pipe has a male thread portion screwed on the outer surface at one end portion of the main body and an inner surface reinforcing member joined along the circumferential direction to the inner surface, and the other steel pipe is threaded on the inner surface at one end portion of the main body. An outer surface reinforcing member joined to the outer surface along a circumferential direction, and the one steel pipe and the other steel pipe are connected and configured by screw connection of the male screw part and the female screw part. A steel pipe connection structure characterized by comprising: The steel pipe connection structure according to claim 1, wherein the inner surface reinforcing member and the outer surface reinforcing member are joined to each steel pipe body by an adhesive. The steel pipe connection structure according to claim 1 or 2, wherein the steel pipe is a steel pipe pile.

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