KR20240004686A - Joint pipe and its manufacturing method, design method, joint pipe-attached steel pipe and its manufacturing method, design method, steel pipe pile, and steel pipe pile construction method - Google Patents

Abstract

A joint pipe that can reduce the effort of straightening the end when mounted on a steel pipe and can be applied to small-diameter steel pipe piles, and its manufacturing method and design method; a steel pipe with a joint pipe and its manufacturing method and design method; a steel pipe pile; and a steel pipe. For the purpose of providing a pile construction method, the joint pipe (1) is a screw-type or plug-in type joint pipe that is mounted on the end of the steel pipe (3) and joins the steel pipe (3), and is attached to the steel pipe (3). In a state in which the outer diameter of the proximal end 1a to be joined is larger than the outer diameter of the steel pipe 3, the inner diameter of the proximal end 1a is smaller than the inner diameter of the steel pipe 3, and the pipe axis is aligned with the steel pipe 3, the proximal end 1a ) The amount of protrusion from the outer peripheral surface of the steel pipe (3) is 9 mm or less.

Description

Joint pipe and its manufacturing method, design method, joint pipe-attached steel pipe and its manufacturing method, design method, steel pipe pile, and steel pipe pile construction method

The present invention relates to a joint pipe used for joining steel pipes, and in particular to a screw-type or plug-in type joint pipe used for small-diameter steel pipe piles, a manufacturing method thereof, a design method, a steel pipe with a joint pipe, a manufacturing method thereof, and a design. It relates to a method, a steel pipe pile, and a construction method of a steel pipe pile.

There is a limit to the length of steel pipe piles for manufacturing or transportation reasons, and it is necessary to join multiple steel pipe piles at the construction site. Conventionally, welding has been used to join these steel pipes, but in recent years, mechanical joints have been increasingly used from the viewpoint of shortening construction time and improving quality control. In particular, for steel pipe piles of small diameter (for example, 406.4 mm or less), equipment for welding can be omitted, and various mechanical joints have been developed and used.

Types of mechanical joints include, for example, screw-type joints as disclosed in Patent Document 1 and those that are joined by inserting a shear key as disclosed in Patent Document 2. This mechanical joint is composed of a pair of joint pipes. Joint pipes, separate from the steel pipe that becomes the main body of the pile, are often manufactured by cutting a short steel pipe, and are previously welded and mounted on the steel pipe of the pile main body at the factory. As shown in Patent Documents 1 and 2, the outer diameter of the joint pipe is generally set to the same diameter as the pile body. This is because there are concerns that the joint protrudes outward from the pile, resulting in a decrease in constructability and a decrease in the frictional force exerted on the main surface when used as a steel pipe pile. For the same reason, for example, in the field of road bridge foundations, the range that does not affect surface friction is limited to 9 mm or less.

Japanese Patent Publication No. 10-311028 Japanese Patent Publication No. 2009-138382

As described above, the joint pipe used in the mechanical joint is manufactured separately from the steel pipe of the pile body and then mounted on the steel pipe by an attachment method such as welding. At this time, especially in the case of a thin structure such as a small-diameter steel pipe pile, the roundness of the end portion is likely to deteriorate, and misalignment may occur when the joint pipe and the steel pipe are brought together. Here, misalignment refers to the radial deviation that occurs between the outer surface shape of the end of the joint pipe and the outer surface shape of the end of the steel pipe when the joint pipe and the steel pipe are in contact, or the radial deviation that occurs in the inner shape of the end of the joint pipe and the inner shape of the end of the steel pipe. refers to the deviation of If there is misalignment, the unevenness of the joint cross section of the joint pipe and the steel pipe in the radial direction becomes non-uniform in the circumferential direction. That is, in some parts of the circumferential direction, the joint pipe becomes a step protruding outward, and in other parts, the steel pipe becomes a step protruding outward. If such uneven steps occur in the joint cross section, there is a risk that stress transmission may become uneven in the circumferential direction when used as a steel pipe with a joint pipe. Therefore, before welding the joint pipe and the steel pipe, it was necessary to correct the end portion (misalignment correction), which was laborious.

The present invention has been made in consideration of the above, and its object is to provide a joint pipe capable of omitting end correction when mounted on a steel pipe, a manufacturing method thereof, and a design method; a steel pipe with a joint pipe and a manufacturing method thereof; and a design method, The object is to provide steel pipe piles and a construction method for steel pipe piles.

The joint pipe related to one aspect of the present invention is a screw-type or plug-in type joint pipe that is mounted on the end of a steel pipe and joins the steel pipe, wherein the outer diameter of the proximal end joined to the steel pipe is larger than the outer diameter of the steel pipe, and the proximal end The inner diameter of is smaller than the inner diameter of the steel pipe, and when the pipe axis is aligned with the steel pipe, the protrusion of the proximal end from the outer peripheral surface of the steel pipe is 9 mm or less.

The manufacturing method of the joint pipe according to one aspect of the present invention is a manufacturing method of manufacturing the joint pipe according to the above invention, wherein a steel pipe on which the joint pipe is mounted is selected, and the outer diameter is larger than the standard dimension of the selected steel pipe and the inner diameter is This small seamless steel pipe is selected within the standard, and the selected seamless steel pipe is used as a material for the joint pipe to form a joint fitting portion in the portion excluding the base end.

The design method of a joint pipe according to one aspect of the present invention is a design method of designing a joint pipe according to the above invention, wherein a steel pipe on which the joint pipe is mounted is selected, and the outer diameter is larger than the standard dimension of the selected steel pipe and the inner diameter is This small seamless steel pipe is selected within the standard, and the selected seamless steel pipe is used as the material for the joint pipe.

A steel pipe with a joint pipe according to one aspect of the present invention is provided with the joint pipe according to the above invention at one or both ends of the steel pipe.

The method for manufacturing a steel pipe with a joint pipe according to one aspect of the present invention includes the step of attaching the joint pipe according to the above invention to one or both ends of the steel pipe.

The design method of a steel pipe with a joint pipe according to one aspect of the present invention is a design method of designing a steel pipe with a joint pipe according to the above invention, wherein a steel pipe on which the joint pipe is mounted is selected, and an outer diameter is smaller than the standard size of the selected steel pipe. This large and small inner diameter seamless steel pipe is selected within the standard, and the joint pipe made of the selected seamless steel pipe is designed to be formed at one or both ends of the steel pipe.

A steel pipe pile according to one aspect of the present invention includes the joint pipe according to the above invention and a plurality of steel pipes joined by the joint pipe.

The construction method of the steel pipe pile according to one aspect of the present invention is a construction method of constructing the steel pipe pile according to the above invention, wherein the steel pipe with the joint pipe attached to the end is formed by standing in the ground. On top of the steel pipe, another steel pipe with the joint pipe attached to its end is placed, and the joint pipes are joined to each other.

In the present invention, the outer diameter of the base end joined to the steel pipe is larger than the outer diameter of the steel pipe, and the inner diameter of the base end is smaller than the inner diameter of the steel pipe, so that the base end is inside and outside the steel pipe on the entire circumference of the joint cross section of the steel pipe and the base end. It can be joined so that it protrudes, so uneven steps in the circumferential direction do not occur. For this reason, when used as a steel pipe with a joint pipe, uneven stress is not transmitted in the circumferential direction, and correction of the ends when mounted on a steel pipe can be omitted. In addition, when the steel pipe and the pipe axis are aligned, the protrusion from the outer peripheral surface of the steel pipe at the base end is 9 mm or less, so it does not affect the friction on the peripheral surface of the pile.

1 is an explanatory diagram illustrating a joint pipe according to an embodiment of the present invention, and is a cross-sectional view of a joint pipe (inner joint pipe) mounted on a steel pipe.
Fig. 2 is a diagram showing the fitted state of joint pipes (inner joint pipe and outer joint pipe) according to one embodiment of the present invention.

The joint pipe according to one embodiment of the present invention will be described using FIG. 1 by taking an inner joint pipe used in a screw-type mechanical joint as an example. Figure 1 is a cross-sectional view of the joint pipe 1 (inner joint pipe) and the steel pipe 3 (steel pipe 4 with the joint pipe) attached with the pipe axes aligned. As shown in FIG. 1, the joint pipe 1 of the present embodiment is attached to the end of the steel pipe 3 constituting the pile body of the steel pipe pile to join the steel pipe 3, and is joined to the steel pipe 3. The outer diameter of the proximal end 1a is larger than the outer diameter of the steel pipe 3, and the inner diameter of the proximal end 1a is smaller than the inner diameter of the steel pipe 3. Additionally, in the drawing, numeral 7 denotes a backing metal and numeral 9 denotes a weld bead.

By making the outer diameter of the proximal end (1a) of the joint pipe (1) larger than the outer diameter of the steel pipe (3) and the inner diameter smaller than the inner diameter of the steel pipe (3), when the joint pipe (1) and the steel pipe (3) are brought together, the proximal end portion (1a) protrudes in and out of the steel pipe (3) in the entire circumferential direction. As a result, uneven steps do not occur in the circumferential direction at the butting portion of the joint pipe (1) and the steel pipe (3), so that when the steel pipe (4) with a joint pipe (steel pipe (3) with a joint pipe (1)) is used, Therefore, stress is transmitted approximately equally in the circumferential direction. Therefore, the joint pipe (1) can be mounted on the steel pipe (3) without straightening the ends of the joint pipe (1) and the steel pipe (3), thereby reducing labor.

Additionally, as described above, if the protrusion of the joint exceeds 9 mm, the friction force between the main surfaces may decrease. In this regard, as shown in FIG. 1, the joint pipe 1 of the present embodiment has the steel pipe 3 and the pipe axis (see dashed and dotted lines in the figure) aligned, and the steel pipe 3 at the base end 1a. ) The amount of protrusion a outward from the outer peripheral surface (see enlarged view of the portion surrounded by a dashed circle in the drawing) is set to 9 mm or less.

In addition, as the above-mentioned joint pipe 1, the inner joint pipe used in a screw-type mechanical joint was explained as an example, but the same applies to the outer joint pipe. Fig. 2 shows a cross-sectional view of the joint pipe 1, which is the inner joint pipe, and the joint pipe 5, which is the outer joint pipe, being fitted together. As shown in Fig. 2, also in the joint pipe 5, the outer diameter of the base end portion 5a is made larger than the outer diameter of the steel pipe 3, and the inner diameter is made smaller than the inner diameter of the steel pipe 3, so that the joint pipe 5 and In a state in which the steel pipe 3 is aligned with the pipe axis (steel pipe 11 with a joint pipe), the base end 5a protrudes in and out of the steel pipe 3 in the entire circumferential direction. As a result, as with the joint pipe 1 (inner joint pipe), uneven steps do not occur in the circumferential direction at the butting portion of the joint pipe 5 and the steel pipe 3, and the steel pipe 11 with the joint pipe (joint pipe (joint pipe) 5) When this attached steel pipe (3)) is used, stress is transmitted approximately evenly in the circumferential direction. In addition, if the protrusion of the proximal end 5a of the joint pipe 5 from the outer peripheral surface of the steel pipe 3 is set to 9 mm or less as in the joint pipe 1, the bearing capacity when the steel pipe 11 with the joint pipe is used is not reduced. .

In addition, Figures 1 and 2 show only one end of the steel pipe with a joint pipe (4) and the steel pipe with a joint pipe (11), but the steel pipe with a joint pipe of the present invention has a joint pipe attached to only one end. It is not limited to that, and also includes those in which joint pipes are mounted on both ends. Specifically, a joint pipe which is an inner joint pipe is provided at one or both ends of a steel pipe, a joint pipe which is an outer joint pipe is provided at one or both ends of a steel pipe, and a joint pipe which is an inner joint pipe is provided at one end of a steel pipe. The pipe, having a joint pipe that is an outer joint pipe at the other end, and all these aspects are included in the present invention.

Next, the manufacturing method of the joint pipe 1 will be explained. The manufacturing method of the joint pipe 1 of this embodiment selects a steel pipe on which the joint pipe 1 is mounted, and selects a seamless steel pipe with an outer diameter larger and an inner diameter smaller than the standard dimension of the selected steel pipe 3 within the standard. And, using the selected seamless steel pipe as a material for the joint pipe (1), a threaded portion is formed in the portion excluding the base end portion (1a), for example, by cutting, to form a joint fitting portion (1b). It is done. Hereinafter, it will be described in detail.

As described above, in the case of a threaded joint pipe, the joint pipe 1 is generally manufactured by cutting a short steel pipe separate from the steel pipe 3 of the pile body. Therefore, the steel pipe 3 on which the joint pipe 1 is mounted is selected, and a short steel pipe with an outer diameter larger and an inner diameter smaller than the standard dimensions (outer diameter and inner diameter) of the selected steel pipe 3 is selected as the material for the joint pipe 1. Just do it.

Here, if the difference in outer diameter between the short steel pipe and the steel pipe 3 constituting the pile main body is 18 mm or less, the protrusion amount a (see Figure 1) when mounted on the joint pipe 1 and the steel pipe 3 is 9 mm or less. Therefore, the joint pipe 1 can be manufactured simply by forming the joint fitting portion 1b (threaded portion) by cutting in the portion excluding the base end portion 1a. If the difference in outer diameter between the short steel pipe and the steel pipe (3) exceeds 18 mm, it is necessary to cut the outer peripheral surface until it becomes 18 mm or less, so the short steel pipe used as the material has an outer diameter slightly greater than the steel pipe of the pile main body. Large is preferable. In this regard, in this embodiment, the joint pipe 1 can be efficiently manufactured by using a seamless steel pipe as a short steel pipe. The reason why the joint pipe 1 can be manufactured efficiently by using a seamless steel pipe will be specifically explained in the design method described later.

Additionally, the steel pipe 4 with a joint pipe can be manufactured by attaching the joint pipe 1 to one or both ends of the steel pipe 3. A common method of attaching the joint pipe (1) to the steel pipe (3) is to place the steel pipe (3) on its side on a turning roller, and attach the joint pipe (1) by welding it to its end. In the construction of a steel pipe pile, it is important that the pipe axes of the steel pipe (3) and the joint pipe (1) coincide, so the joint pipe (1) and the steel pipe (3) are welded with this in mind. Since the joint pipe (1) and the steel pipe (3) have different outer diameters, the turning roller is rotated while the joint pipe (1) is temporarily attached to the steel pipe (3), so that the pipe axes of the joint pipe (1) and the steel pipe (3) are aligned. Just check if they match.

If the pipe axes of the joint pipe (1) and the steel pipe (3) are aligned as described above, the backing metal (7) is mounted on the inner side of the steel pipe (3) to penetrate the entire circumference from the outer side of the steel pipe (3). Main welding is done by welding. As described above, the joint pipe 1 of the present embodiment has a shape that protrudes outward from the steel pipe 3 in the entire circumferential direction when the pipe axis is aligned with the steel pipe 3, so correction of the end portion is required. There is no need for welding, and welding is easy. Additionally, depending on the required strength of the joint pipe 1, fillet welding may be used instead of penetration welding.

Next, the design method of the joint pipe 1 will be explained. The design method of the joint pipe 1 of this embodiment selects the steel pipe 3 on which the joint pipe 1 is mounted, and specifies a seamless steel pipe whose outer diameter is larger and whose inner diameter is smaller than the standard dimension of the selected steel pipe 3. It is characterized in that the selected seamless steel pipe is used as a material for the joint pipe (1). This will be explained in detail below.

As for the steel pipe (3) constituting the main body of the steel pipe pile, electro-welded steel pipes, seamless steel pipes, sheet-coated steel pipes, etc. are used. Hereinafter, since electric resistance welded pipes are generally used as steel pipe piles, the case where electric resistance welded steel pipes are used for the steel pipe 3 will be described as an example. Electrically welded steel pipes are industrial products and their outer diameter and plate thickness are standardized. Therefore, based on the ground and load conditions of the construction site, the electrically welded steel pipes that make up the steel pipe (3) are selected from the standard dimensions of electrically welded steel pipes generally used as steel pipe piles. Choose.

Next, based on the standard dimension (outer diameter) of the selected electric resistance welded steel pipe, a short steel pipe to be the material for the joint pipe 1 is selected. At this time, it is necessary to select a pipe with a larger outer diameter than the steel pipe (3), but if one size larger is selected within the same electric resistance welded steel pipe standard as the steel pipe (3), the outer diameter becomes significantly larger. Since the joint pipe 1 of this embodiment needs to have the above-described protrusion a (see Fig. 1) to 9 mm or less, a steel pipe with a significantly larger outer diameter than the steel pipe 3 is used as the material for the joint pipe 1. If so, the amount of cutting increases and costs increase.

Therefore, in this embodiment, a seamless steel pipe is used as the material of the joint pipe 1. Seamless steel pipes are also standardized as industrial products, but the standards of seamless steel pipes correspond to various sizes, and the size suitable as the joint pipe 1 of this embodiment, that is, the outer diameter is slightly larger than the standard size of the electric resistance welded steel pipe described above. It is also included in the standard. Table 1 shows the specifications of the outer diameter of the electric resistance welded steel pipe used for the steel pipe 3, and also shows that a suitable seamless steel pipe is selected within the standard as the joint pipe 1 to be mounted on this.

For example, if the steel pipe 3 is an electrically welded steel pipe with an outer diameter of 165.2 mm, and the joint pipe 1 attached to it is also an electrically welded steel pipe, an electrically welded steel pipe with an outer diameter of 190.7 mm, which is one size larger, is used. When a joint pipe (1) with an outer diameter of 190.7 mm is mounted on a steel pipe (3) with an outer diameter of 165.2 mm, the protrusion amount a exceeds 9 mm, so cutting processing to reduce the outer diameter of this electric resistance welded steel pipe is required, resulting in processing costs. do.

On the other hand, if the joint pipe 1 is a seamless steel pipe, a seamless steel pipe with an outer diameter of 168.3 mm can be used. If it is a seamless steel pipe with an outer diameter of 168.3 mm, cutting to reduce the outer diameter is unnecessary, and the joint pipe 1 with a protrusion amount a of 9 mm or less can be manufactured only by cutting the joint fitting portion 1b.

Additionally, when the steel pipe 3 is an electrowelded steel pipe with an outer diameter of 406.4 mm, a seamless steel pipe with an outer diameter of 426.0 mm is used. Therefore, in order to reduce the protrusion amount a to 9 mm or less, cutting processing to reduce the outer diameter of the seamless steel pipe is necessary, but since the cutting amount is about 1 mm, processing is easy.

Additionally, what is shown in Table 1 is the standard diameter, and the end portion of the steel pipe that is actually manufactured is larger than the standard diameter because the outer diameter, inner diameter, and thickness change in the circumferential direction or become elliptical, but are smaller than the standard diameter. There is a part where you lose. Since the diameter difference between the seamless steel pipe and the electrically welded steel pipe described above is small, cases where the diameters of the electrically welded steel pipe and the seamless steel pipe deviate from the standard diameter were also examined.

In the standards for steel pipe piles, it is stipulated that the roundness defined by the following equation (1) is 1.0% or less.

Roundness = (maximum diameter - minimum diameter) / screed diameter × 100... (One)

In addition, the maximum diameter and minimum diameter in equation (1) are those at the welded portion of the steel pipe.

For example, when the roundness of the steel pipe (3) (electrically welded steel pipe) and the joint pipe (1) (seamless steel pipe) are each 1%, the largest diameter part of the steel pipe (3) and the minimum diameter part of the joint pipe (1) are butted. On the ground, it is conceivable that the steel pipe (3) protrudes outward from the joint pipe (1) in this part. This point can be prevented by adjusting the direction of each maximum diameter during alignment before welding. Therefore, it is sufficient to consider the case where the part of the steel pipe 3 that is +0.5% of the standard diameter and the part that is -0.5% of the standard diameter in the joint pipe 1 are butted together. The results are shown in Table 2.

As shown in Table 2, when comparing the value obtained by multiplying the standard diameter of the electrowelded steel pipe shown in Table 1 by 1.005 times (+0.5%) and the value obtained by multiplying the standard diameter of the seamless steel pipe by 0.995 times (-0.5%), in any case, The outer diameter of the seamless steel pipe is larger than the outer diameter of the electrowelded steel pipe. As described above, when a seamless steel pipe is used as the material for the joint pipe (1), even if deformation occurs in the electric resistance welded steel pipe (steel pipe (3)) or the seamless steel pipe (joint pipe (1)), the standard allowable If it is of this level, it can be considered that there is no problem in welding and joining the joint pipe (1) and the steel pipe (3).

In addition, since the plate thickness of the seamless steel pipe can be freely set, it is easy to set the inner diameter to be smaller than the inner diameter of the steel pipe 3 (electrically welded steel pipe). This point is explained using Table 3.

Table 3 shows the general plate thickness when electric welded steel pipes of each outer diameter shown in Table 1 are used for steel pipe piles (steel pipe (3)) and the manufacturing plate thickness range of seamless steel pipes of each outside diameter shown in Table 1. For example, in Table 2, the inner diameter of an electro-welded steel pipe with an outer diameter of 165.2 mm and a plate thickness of 5.6 mm is 154 mm, and the inner diameter of an electro-welded steel pipe with an outer diameter of 165.2 mm and a plate thickness of 7.1 mm is 151 mm. In contrast, the manufacturing plate thickness range of a seamless steel pipe with an outer diameter of 168.3 mm is 4.0 mm or more and 40 mm or less. Therefore, the plate thickness can be set within this production plate thickness range so that the inner diameter is less than 154 mm or 151 mm.

Additionally, the steel pipe 4 with a joint pipe can be designed by designing the joint pipe 1 described above to be formed at one or both ends of the steel pipe 3. Specifically, the steel pipe (3) on which the joint pipe (1) is mounted is selected, a seamless steel pipe with an outer diameter larger and an inner diameter smaller than the standard dimension of the selected steel pipe (3) is selected within the standard, and the selected seamless steel pipe is used as a material. By designing the joint pipe 1 to be formed at one or both ends of the steel pipe 3, the steel pipe 4 with a joint pipe of the present embodiment can be designed.

In addition, the manufacturing method and design method of the joint pipe described above and the manufacturing method and design method of the steel pipe with joint pipe are the joint pipe (1) which is an inner joint pipe and the steel pipe with joint pipe (4) provided with the joint pipe (1). ) was explained as an example, but the same applies to the joint pipe 5, which is an outer joint pipe, and the steel pipe 11 with a joint pipe provided with the joint pipe 5.

As described above, in the joint pipe 1 of the present embodiment, the outer diameter of the proximal end 1a of the joint pipe 1 is larger than the outer diameter of the steel pipe 3, and the inner diameter of the proximal end 1a is larger than the outer diameter of the steel pipe 3. ), it is possible to reduce the effort of straightening the ends of the joint pipe (1) and the steel pipe (3) when mounting it on the steel pipe (3). In addition, when the pipe axis is aligned with the steel pipe 3, the amount of protrusion from the outer peripheral surface of the steel pipe 3 is 9 mm or less, so even when applied to a steel pipe pile, a predetermined bearing force can be exerted. In particular, when the joint pipe (1) of the steel pipe with a joint pipe (4) and the joint pipe (5) of the steel pipe with a joint pipe (11) are joined to form a steel pipe pile, the protrusion amount is all 9 mm or less, so it can be safely It is more suitable because it can provide a certain amount of support. In particular, when the present invention is applied to steel pipe piles with an outer diameter of 406.4 mm or less, commonly referred to as “small diameter”, the manufacturing effort can be greatly reduced, making it possible to lower the manufacturing cost. In addition, since steel pipe piles with an outer diameter of 406.4 mm or less are often rotary penetration piles, the present invention, which has little effect on the friction of the pile's main surface, is more preferable. Additionally, by using a seamless steel pipe as the material for the joint pipe 1, the cutting amount when cutting the material can be suppressed to a minimum, thereby reducing manufacturing costs.

In the above-described embodiment, the explanation was given as an example of a screw-type joint pipe in which the joint pipes are fitted with each other by screws formed in the joint fitting portion. However, the joint pipe, manufacturing method, and design method of the present invention are not limited to this. no. For example, by inserting the inner joint pipe into the outer joint pipe, the convex portion formed on the outer peripheral surface of the inner joint pipe and the concave portion formed on the inner peripheral surface of the outer joint pipe are engaged, so that the joint pipes fit together.

Furthermore, in the above-described embodiment, the joint fitting portions 1b and 5b of the joint pipes 1 and 5 were formed by cutting, but the present invention is not limited to this. The joint fitting portions 1b and 5b may be formed using other known or unknown techniques, and even in that case, the effect of the present invention can be obtained. However, the joint pipe of the present invention is not limited to the joint fitting part processed later on the steel pipe as the material as described above, but the joint fitting part is manufactured simultaneously using, for example, casting or a 3D printer. It's okay.

In addition, in the above-described method of manufacturing a steel pipe with a joint pipe, an example of attaching the joint pipes 1 and 5 to the end of the steel pipe 3 by welding has been described, but the present invention is not limited to this. The joint pipes (1, 5) can be reliably joined to the steel pipe (3) with the pipe axis aligned with the steel pipe (3), can withstand various loads applied during construction or use, and can also exert bearing capacity as a steel pipe pile. If possible, other mounting methods may be used.

In addition, in the above-described embodiment, a joint pipe and a steel pipe with a joint pipe are explained, but at a construction site, etc., a steel pipe pile can be formed by connecting joint pipes of a plurality of steel pipes with a joint pipe. You can. That is, the steel pipe pile includes the joint pipe described in the above-described embodiment and a plurality of steel pipes joined by this joint pipe.

In addition, when constructing the above-mentioned steel pipe pile, a steel pipe with a joint pipe attached to the end (steel pipe with a joint pipe) is formed by standing in the ground, and on top of this steel pipe, another steel pipe with a joint pipe attached to the end is placed (another steel pipe). All you have to do is place a steel pipe with a joint pipe and join the joint pipes together.

The present invention is suitable for application to joint pipes used for joining steel pipes, especially screw-type or plug-in type joint pipes used for small-diameter steel pipe piles.

1: Joint pipe (inner joint pipe)
1a: proximal end
1b: Joint fitting part
3: steel pipe
4: Steel pipe with joint pipe attachment
5: Joint pipe (outer joint pipe)
5a: proximal end
5b: Joint fitting part
7: Backing metal
9: weld bead
11: Steel pipe with joint pipe attachment

Claims (8)

A screw-type or plug-in type joint pipe that is mounted on the end of a steel pipe and joins the steel pipe,
The outer diameter of the base end joined to the steel pipe is larger than the outer diameter of the steel pipe,
The inner diameter of the proximal end is smaller than the inner diameter of the steel pipe,
Additionally, a joint pipe in which the protrusion of the base end portion from the outer peripheral surface of the steel pipe is 9 mm or less when the steel pipe and the pipe axis are aligned. A manufacturing method for manufacturing the joint pipe according to claim 1, comprising:
Select a steel pipe on which the joint pipe is mounted,
Selecting a seamless steel pipe with an outer diameter larger and an inner diameter smaller than the standard dimensions of the selected steel pipe within the standard,
A method of manufacturing a joint pipe, wherein the selected seamless steel pipe is used as a material for the joint pipe and a joint fitting portion is formed in a portion excluding the base end portion. As a design method for designing the joint pipe according to claim 1,
Select a steel pipe on which the joint pipe is mounted,
Selecting a seamless steel pipe with an outer diameter larger and an inner diameter smaller than the standard dimensions of the selected steel pipe within the standard,
A method of designing a joint pipe, wherein the selected seamless steel pipe is used as a material for the joint pipe. A steel pipe with a joint pipe, comprising the joint pipe according to claim 1 at one or both ends of the steel pipe. A method of manufacturing a steel pipe with a joint pipe, comprising the step of attaching the joint pipe according to claim 1 to one or both ends of the steel pipe. As a design method for designing a steel pipe with a joint pipe according to claim 4,
Select a steel pipe on which the joint pipe is mounted,
Selecting a seamless steel pipe with an outer diameter larger and an inner diameter smaller than the standard dimensions of the selected steel pipe within the standard,
A method of designing a steel pipe with a joint pipe, wherein the joint pipe made of the selected seamless steel pipe is designed to be formed at one or both ends of the steel pipe. The joint pipe described in paragraph 1,
A steel pipe pile comprising a plurality of steel pipes joined by the joint pipe. A construction method for constructing the steel pipe pile according to paragraph 7,
A method of constructing a steel pipe pile, wherein a steel pipe with the joint pipe attached to an end is formed by standing in the ground, and another steel pipe with the joint pipe attached to the end is placed on top of the steel pipe, and the joint pipes are joined to each other.