JPH06193055A - Steel pipe pile with screw joint - Google Patents

Abstract

(57) [Abstract] [Purpose] To complete the joining work of the steel pipes that make up the steel pipe pile in a short time and very easily. [Structure] A female screw is formed on the end of the steel pipe 1 constituting the steel pipe pile 3, and at the both ends of the coupling 2 for joining two or more steel pipes 1 in the longitudinal direction thereof, the male screw of the steel pipe 1 is screwed. Cut the screw.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel pipe pile constructed in the field of civil engineering, construction, and marine structures, for example, to prevent landslides.

[0002]

2. Description of the Related Art Steel pipe piles used for landslide prevention, etc.
There are some that can reach up to several tens of meters, but due to restrictions on production equipment, transportation from the production site, construction restrictions on the consumption site, etc., the length of one steel pipe pile produced is limited. Therefore, the present steel pipe pile is used by joining two or more steel pipes in the longitudinal direction.

As a method for joining steel pipes to this steel pipe pile, conventionally, as shown in FIG. 4, the ends of the steel pipes provided with grooves 6 are butted, and a core ring 7 is interposed on the inner surface of the welded portion, and the above-mentioned opening is performed. Circumferential welding in 6 above, or JP-A-64
No. 33313 proposed in FIG. 5, that is, the sleeve 8 is loosely fitted to the outer periphery of the joint portion of the steel pipe, and then the solidification material 9 is filled into the inner surface of the sleeve 8 to fix the steel pipe and the sleeve 8 together. The method of doing was done.

[0004]

However, in the method of circumferential welding, the welding operation requires a long time (about 2 hours per welding). In a welding operation, a skilled technique is required to obtain a good joining result. Since the welding work is carried out at the construction site where the steel pipe pile is used, the progress of other work is hindered during the welding work, and it becomes difficult to efficiently perform the work of installing the steel pipe pile. It is necessary to select the welding material according to the material of the steel pipe pile. In the case of high-strength steel, it is necessary to perform heat treatment after welding, and the heat treatment work is also extremely difficult. Inspection of the weld by radiation is required after the welding operation. There was the above problem.

Further, in the method disclosed in JP-A-64-33313, in order to firmly fix the steel pipe and the sleeve, it is necessary to remove foreign matters such as scale and oil on the surface of the steel pipe. If a filling and solidifying material having a higher compressive strength than the steel pipes to be joined is not used, when the bending force acts, the filling and solidifying material 9a on one side is compressed and the filling material 9b on the other side is compressed as shown in FIG. The sleeve 8 is peeled off, and the strength of the entire joint is reduced. There was the above problem.

The present invention was devised in view of the above problems of the prior art, and it is an object of the present invention to provide a steel pipe pile capable of completing the joining work of the steel pipes in a very short time and very easily. .

[0007]

Therefore, the steel pipe pile according to the present invention is a steel pipe pile formed by joining two or more steel pipes in the longitudinal direction via a coupling, wherein the steel pipe end portion and the coupling end are It is characterized in that the parts are screwed together.

Further, in the present invention, in order to strengthen the joining of the steel pipes, an abutting shoulder is provided so that the steel pipe and the coupling abut each other when the steel pipe end portion and the coupling end portion are screwed together. Of course, the coupling and the steel pipe may be formed.

[0009]

[Operation] To join steel pipes forming a steel pipe pile, only the ends of the steel pipe and the coupling need to be screwed together, which eliminates the need for welding work and filling work of the filling and solidifying material as in the past.
The work will be completed in a very short time and easily.

Further, when abutting shoulders are formed on the coupling and the steel pipe such that the steel pipe and the coupling abut each other when the two are screwed together,
In addition to the screwing action, the steel pipe and the coupling are firmly fixed to each other in the butting shoulder, so that the joint becomes stronger and the strength of the steel pipe pile is increased.

[0011]

Embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following examples.

FIG. 1 shows an embodiment of a steel pipe pile 3 according to the present invention. FIG. 1 (a) shows a steel pipe 1 forming the steel pipe pile 3 and FIG. 1 (b) shows a coupling 2. . In this embodiment, the steel pipe pile 3 has a size of 318.5 mmφ × 23.0 mmt.

The steel pipe 1 is cut with a tapered male screw which is screwed into a female screw of a coupling 2 described later within a range of a length of 300 mm from the end thereof.

The coupling 2 has a cylindrical shape having an inner diameter larger than the outer diameter of the steel pipe 1, and has an outer diameter of 364 mm, and the male screw of the steel pipe 1 is provided at both ends thereof. Tapered female threads are cut at both ends so that they can be screwed together.

By screwing the ends of the steel pipe 1 and the ends of the coupling 2 formed as described above, the steel pipe pile 3 of this embodiment is formed as shown in FIG. Therefore, the steel pipe pile 3 of the present embodiment can be easily formed in an extremely short time.

Next, another embodiment according to the present invention is shown in FIG. In this embodiment, abutting shoulders are formed on the coupling and the steel pipe so that the steel pipe 10 and the coupling 20 abut each other when the end of the steel pipe 10 and the end of the coupling 20 are screwed together. That is, the steel pipe 10 is formed with the outer surface shoulder 11 at a position at a predetermined distance from the tip end surface 12, and the coupling 20 has an inner surface shoulder 21 with which the tip end surface 12 of the steel pipe 10 abuts at the center thereof, and an end. An outer surface shoulder 22 with which the outer surface shoulder 11 of the steel pipe 10 abuts is formed near the portion. The structure is the same as that of the previous embodiment except that the shoulders 11, 21, 22 are formed.

Also in this embodiment, if the ends of the steel pipe 10 and the ends of the coupling 20 are screwed together, the steel pipe pile can be easily formed in a very short time. Also,
In this embodiment, the tip surface 12 of the steel pipe 10 and the inner shoulder 21 of the coupling 20 and the outer shoulder 22 of the coupling 20 and the steel pipe
Since the outer surface shoulders 11 of 10 are screwed in contact with each other, the steel pipe 10 and the coupling 20 are firmly joined, and there is no problem in the strength of the steel pipe pile. There is.

Next, a pure bending test was conducted using various sizes and materials for the first and second embodiments, and the strength was tested. The results are shown in Table 1.
Shown in. In addition, this pure bending test, as shown in FIG.
The test beam 3 is to be applied by the loading beam 5 with two points sandwiching the coupling 2 as fulcrums 4. Here, the bending yield strength ratio is the ratio of the yield stress of the joint portion and the steel pipe body, and the bending fracture load ratio is the ratio of the load of the joint portion and the steel pipe body when the joint portion breaks. % Indicates that the joint portion has a higher strength than the steel pipe body.

[0019]

[Table 1]

As shown in the above table, even in the first embodiment,
The bending yield strength ratio is 70.5% and the bending load ratio is 63.5%, which shows that there is no problem in terms of strength. Further, in the second example, the bending yield strength ratio was 95.0 to 110.9.
%, The load ratio at bending fracture is 91.8 to 118.3%, which is an extremely high value, indicating that there is no problem in terms of strength as a steel pipe pile.

Further, in the second embodiment, a test was conducted while the strength ratio was changed depending on the method of screwing the steel pipe 10 and the coupling 20, that is, the method of tightening. The results are shown in Table 2.

[0022]

[Table 2]

As shown in the above table, the strength does not change at a high value by any tightening method, and it can be seen that the structure of Example 2 can maintain high strength regardless of the tightening method. .

[0024]

As described above, according to the steel pipe pile according to the present invention, only by screwing the end portions of the steel pipe, the welding work and the filling work of the filling and solidifying material are not required unlike the prior art. The joining work can be performed easily in an extremely short time.

[Brief description of drawings]

1 shows a first embodiment of a steel pipe pile according to the present invention, (a)
FIG. 3 is a cross-sectional view of an end portion of a steel pipe with a male screw cut, (b) is a cross-sectional view of a coupling with a female screw cut, and (c) is a cross-sectional view showing a state in which a steel pipe and a coupling are screwed together.

FIG. 2 is a sectional view showing a second embodiment of the steel pipe pile according to the present invention and showing a state in which the steel pipe and the coupling are screwed together.

FIG. 3 is an explanatory diagram showing an outline of a pure bending test.

FIG. 4 is a cross-sectional view illustrating an example of a conventional method for joining steel pipe piles by welding.

FIG. 5 is a partial cross-sectional view illustrating a method for joining steel pipe piles disclosed in JP-A-64-33313.

FIG. 6 is a partial cross-sectional view illustrating one problem of the method for joining steel pipe piles disclosed in JP-A-64-33313.

[Explanation of symbols] 1,10 Steel pipe 2,20 Coupling 11,22 Outer shoulder 21 Inner shoulder

Front Page Continuation (72) Inventor Takeshige Katsumata, 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd.

Claims (2)

[Claims] 1. A steel pipe pile formed by joining two or more steel pipes in a longitudinal direction through a coupling, wherein the steel pipe end portion and the coupling end portion are screwed together. Steel pipe pile to have. 2. A steel pipe pile having a threaded joint according to claim 1, wherein when the steel pipe end portion and the coupling end portion are screwed together, a butting shoulder is provided so that the steel pipe and the coupling abut against each other. The steel pipe pile having a threaded joint portion according to claim 1, wherein the steel pipe pile is formed in a ring and a steel pipe.