JP2022136379A - Method for manufacturing steel pipe sheet pile with mechanical joint pipe - Google Patents

Abstract

To provide a manufacturing method which manufactures a steel pipe sheet pile, including a joint pipe on outer peripheral surfaces of a steel pipe body and a mechanical joint pipe provided at an end of the steep pipe body, while securing circularity of the mechanical joint pipe.SOLUTION: A manufacturing method of a steel pipe sheet pile having a mechanical joint pipe of the invention includes: a first pipe attachment step S1 in which a first pipe 15 is attached to an outer peripheral surface which is spaced apart from an end of a steel pipe body 3 by a distance of 200 mm or longer; a first slit formation step S3 in which a first slit 15a is formed at the first pipe 15 after the first pipe attachment step S1; a mechanical joint pipe attachment step S5 in which a mechanical pipe joint 9 is attached after the first slit formation step S3; a second pipe attachment step S7 in which a second pipe 17 provided with a second slit 17a is fixed to the outer peripheral surface of the steel pipe body 3 and an end of the first pipe 15 and one end part of the second pipe 17 are welded after the mechanical joint pipe attachment step S5; and a slit communication step S9 in which communication between the first slit 15a and the second slit 17a is established after the second pipe attachment step S7.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a steel pipe sheet pile having a mechanical joint pipe such as a screw type at the end of a steel pipe body, and a joint pipe extending in the pipe axial direction on the outer peripheral surface of the steel pipe body and the mechanical joint pipe. .

Conventionally, with respect to the steel pipe sheet piles 23 shown in FIGS. 8 and 9, welding has been mainly used to connect the upper and lower steel pipe sheet piles 23 to each other in the pipe axial direction. Mechanical joints are increasingly being used in place of welding because welding and inspection takes a long time in the field or in the field where many short pipes must be connected due to headroom restrictions. There are various types of mechanical joints, but a commonly used structure is, for example, a threaded joint.
By providing such a mechanical joint at the end of the steel pipe main body 3 in advance at the time of manufacture, it is possible to connect the upper and lower steel pipe sheet piles 23 by rotationally fitting the screw joint at the work site. can save time.

On the other hand, the steel pipe sheet piles 23 are provided with joint pipes 7 for connecting the adjacent steel pipe sheet piles 23 to each other on the outer peripheral surface of the steel pipe body 3 . This joint pipe 7 is also attached to the outer peripheral surface of the steel pipe main body 3 in advance at the time of manufacture in the same manner as the mechanical joint described above. Sometimes.

On the other hand, Patent Literature 1 discloses a steel pipe sheet pile in which the roundness of pipe ends is ensured and a manufacturing method thereof. In the method disclosed in Patent Document 1, "at least a nail is welded to the inner peripheral part of the pipe end of the steel pipe sheet pile, which is most affected by heat shrinkage, and other parts that are not affected by heat shrinkage. It is said that the roundness and flatness of the pipe ends can be ensured by joining the ribs that fix the pipes to each other. The "claw" in Patent Document 1 is the same as the joint pipe 7 provided on the outer peripheral surface of the steel pipe body 3 described above.

In addition, in Patent Document 1, even when mechanical joints are attached to the ends of the steel pipe sheet piles, "Since the flatness of the pipe ends of the steel pipe sheet piles is maintained, the mechanical joints and the steel pipe sheet piles can be welded uniformly. Because the entire circumference can be welded under certain conditions, mechanical joints can be attached with uniform welding quality without bending.”

JP 2009-166084 A

In the method of Patent Document 1, after the joint pipe 7 is attached to the outer peripheral surface of the steel pipe body 3, the mechanical joint is attached to the end of the steel pipe body. Not done.
In such a steel pipe sheet pile 23, after the upper and lower steel pipe sheet piles 23 are connected to each other by a mechanical joint at the construction site, it is necessary to separately weld the joint pipe 7 to the portion where the joint pipe 7 of the upper and lower steel pipe sheet piles 23 is connected. (part shown in gray in FIG. 8).

On the other hand, in order to save manpower and labor in on-site construction, there is a demand to preliminarily attach the joint pipe 7 to the outer peripheral surface of the mechanical joint at the time of manufacture so that the work of installing the joint pipe 7 at the site is unnecessary. was there.
However, if the pipe, which is the raw material of the joint pipe 7, is welded to the outer peripheral surface of the mechanical joint during manufacture, the circularity of the mechanical joint changes due to the heat effect during installation. After the pipes are welded together, a slit 7a extending in the pipe axial direction is formed in the pipe in order to form a joint pipe 7 having a C-shaped cross section (see FIG. 9). A deformation occurs in which the part that formed the is about to open. As a result, stress is redistributed in the steel pipe body 3 welded to the joint pipe 7 and in the mechanical joint, and the out-of-roundness of the mechanical joint further changes.

In the case of a mechanical joint such as the threaded joint described above, which is connected by rotational fitting, the change in roundness increases the resistance during fitting, resulting in deterioration of work efficiency or failure to fit. I had a problem with it disappearing.

The present invention has been made in order to solve the above problems. It is an object of the present invention to provide a manufacturing method while ensuring the degree.

(1) A method for manufacturing a steel pipe sheet pile having a mechanical joint pipe according to the present invention has a mechanical joint pipe at the end of a steel pipe body, and the outer peripheral surface of the steel pipe body and the mechanical joint pipe is provided in the pipe axial direction. In a method for manufacturing a steel pipe sheet pile having an extending joint pipe, a first pipe attaching step of attaching a first pipe, which is a part of the joint pipe, to the outer peripheral surface of the steel pipe body at a distance of 200 mm or more from the end of the steel pipe body by welding. and, after the first pipe attaching step, a first slit forming step of forming a first slit extending in the pipe axial direction in a portion of the first pipe excluding the end portion, and after the first slit forming step, the After the mechanical joint pipe mounting step of mounting the mechanical joint pipe to the end portion of the steel pipe body, and the mechanical joint pipe mounting step, a second slit extending in the pipe axial direction is provided in advance in a portion excluding one end portion. A second pipe, which forms the joint pipe together with the first pipe, is arranged so that the one end portion is brought into contact with the end portion of the first pipe, and the second slit is coaxial with the first slit of the first pipe. a second pipe mounting step of fixing to the outer peripheral surface of the steel pipe body so as to be positioned at the end of the first pipe and welding the end of the first pipe and one end of the second pipe; and the second pipe mounting step and a slit connecting step of forming slits in the ends of the first pipe and the second pipe to connect the first slit and the second slit.

(2) In addition, in the above (1), in the first pipe mounting step, the first pipe is arranged so that its end is located within 500 mm from the end of the steel pipe body, and In the second pipe mounting step, the second pipe is fixed to the steel pipe body by partial welding.

In the present invention, the first pipe constituting the joint pipe is attached and the slit is formed before the mechanical joint pipe is attached. Welding joints minimizes the thermal effects during installation of joint pipes and the effects during slit processing, and the joint pipes are provided on the outer peripheral surface of the steel pipe body and the mechanical joint pipes provided at the ends. The steel pipe sheet pile can be manufactured while ensuring the roundness of the mechanical joint pipe.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing explaining the process of the manufacturing method of the steel pipe sheet pile concerning one embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing explaining the manufacturing method of the steel pipe sheet pile concerning one embodiment of this invention. FIG. 3 is an end view of the vicinity of the upper and lower connecting portions of the steel pipe sheet pile according to the embodiment of the present invention; 4 is a cross-sectional view taken along line AA in FIG. 3; FIG. FIG. 10 is an explanatory diagram of Comparative Example 1 in Examples. FIG. 10 is an explanatory diagram of Comparative Example 2 in Examples. It is a graph for demonstrating the effect of the example of this invention in an Example. It is a side view of the conventional steel pipe sheet pile. It is a top view of the conventional steel pipe sheet pile.

A method for manufacturing a steel pipe sheet pile according to an embodiment of the present invention includes a mechanical joint pipe at the end of a steel pipe body and a joint pipe extending in the pipe axial direction on the outer peripheral surface of the steel pipe body and the mechanical joint pipe. A steel pipe sheet pile is manufactured, and as shown in FIGS. 1 and 2, a first pipe installation step S1, a first slit formation step S3, a mechanical joint pipe installation step S5 and a second pipe installation step S7 and a slit connecting step S9.
Prior to the description of the manufacturing method, first, the steel pipe sheet pile according to the present embodiment will be described in detail with reference to FIGS. 3 and 4. FIG.

FIG. 3 is an end view of a state in which the upper and lower steel pipe sheet piles are connected in the pipe axis direction, and the vicinity of the connecting portion is cut in the pipe axis direction, and FIG. .
As described above, the steel pipe sheet pile 1 according to the present embodiment has the mechanical joint pipe 5 at the end of the steel pipe main body 3, and the joint extending in the pipe axial direction on the outer peripheral surface of the steel pipe main body 3 and the mechanical joint pipe 5 A tube 7 is provided.

The mechanical joint pipe 5 has an outer joint pipe 9 having a female thread and an inner joint pipe 11 having a male thread. It is placed inside. FIG. 3 shows an example in which an inner joint pipe 11 is provided at the lower end of the steel pipe body 3 on the upper side in the figure, and an outer joint pipe 9 is provided at the upper end of the steel pipe body 3 on the lower side in the figure.

As shown in FIG. 4, the outer joint pipe 9 and the inner joint pipe 11 are provided with tapped holes 9a and 11a for inserting anti-rotation bolts 13, so that the outer joint pipe 9 and the inner joint pipe 11 are connected. By inserting the anti-rotation bolt 13 into the tapped holes 9a and 11a in the fitted state, it is possible to prevent the inner joint pipe 11 from rotating in the opposite direction and becoming disengaged.

A joint pipe 7 extending in the direction of the pipe axis is provided at a position facing each other on the outer peripheral surfaces of the steel pipe body 3 and the mechanical joint pipe 5 (the outer joint pipe 9 and the inner joint pipe 11). In a state where the upper and lower steel pipe sheet piles 1 are connected by fitting, the end portion of the joint pipe 7 on the side of the upper steel pipe sheet pile 1 provided with the inner joint pipe 11 and the lower end portion provided with the outer joint pipe 9 The ends of the joint pipes 7 on the steel pipe sheet pile 1 side are in contact or close to each other.

Each step of the method for manufacturing the steel pipe sheet pile 1 configured as described above will be specifically described below with reference to FIGS. 1 and 2 . Note that FIG. 2 illustrates a case where the outer joint pipe 9 is provided at the end of the steel pipe body 3 .

<First pipe mounting process>
The first pipe mounting step S1 is, as shown in FIG. 2(a), a step of mounting a first pipe 15, which will be a part of the joint pipe 7, on the outer peripheral surface of the steel pipe body 3 at a distance a from the end. .
The first pipe 15 is attached by full-length welding, and the distance a between the end of the first pipe 15 and the end of the steel pipe body 3 is set to 200 mm or more. The reason for setting the distance a to 200 mm or more is as follows.

The end portion of the first pipe 15 is a portion to be welded to the second pipe 17 in the subsequent second pipe mounting step S7. If the distance a is 200 mm or more, the mechanical joint pipe 5 is less likely to be thermally affected when the first pipe 15 and the second pipe 17 are welded together, so the influence on roundness can be reduced.
In addition, by providing a distance a of 200 mm or more between the end of the first pipe 15 and the end of the steel pipe body 3, this portion can be used as a portion to be fixed on a workbench or the like. Workability in the mounting work and in the subsequent steps is improved.

<First slit forming step>
In the first slit forming step S3, after the first pipe attaching step S1, as shown in FIG. 2B, a first slit 15a extending in the pipe axial direction is formed in a portion of the first pipe 15 excluding the end portion. It is a process.
The first slit 15a is formed by fusion cutting (gas cutting, plasma cutting, etc.).
The reason for forming the first slit 15a except for the end of the first pipe 15 is as follows.

When a slit is formed in the first pipe 15 over the entire length in the pipe axial direction, the slit is deformed to open as described above. Such deformation causes a problem that the end face of the first pipe 15 and the end face of the second pipe 17 do not match when welding to the second pipe 17 in the subsequent second pipe mounting step S7.

In this respect, in the present embodiment, since the first slit 15a is not formed at the end of the first pipe 15, the shape of the end is maintained, and the above problem does not occur.
Considering the prevention of deformation of the end portion of the first pipe 15 and workability in the slit connecting step S9, the distance b between the pipe end of the first pipe 15 and the first slit 15a is preferably about 20 mm to 80 mm. preferable.

<Mechanical fitting pipe installation process>
In the mechanical joint pipe mounting step S5, after the first slit forming step S3, as shown in FIG. It is a process.
Attachment of the outer joint pipe 9 is performed by all-around welding.

<Second pipe mounting process>
The second pipe mounting step S7 is a step of mounting the second pipe 17 after the mechanical joint pipe mounting step S5, as shown in FIG. 2(d).
The second pipe 17 constitutes the joint pipe 7 together with the first pipe 15 and has a length extending from the end of the outer joint pipe 9 to the end of the first pipe 15 . Further, the second pipe 17 is provided with a second slit 17a extending in the axial direction in a portion other than one end.
The reason why the second slit 17a is formed excluding one end of the second pipe 17 is to prevent deformation of the end like the first slit 15a of the first pipe 15 . Also, the distance c between the end of the second pipe 17 and the second slit 17a is preferably about 20 mm to 80 mm, like the distance b of the first pipe 15. As shown in FIG.

The attachment of the second pipe 17 is performed as follows.
First, one end of the second pipe 17 is brought into contact with the end of the first pipe 15, and the second slit 17a and the first slit 15a of the first pipe 15 are positioned on the same axis.
Next, the second pipe 17 is fixed to the outer peripheral surface of the steel pipe body 3 by welding or the like.
Then, the end of the first pipe 15 and one end of the second pipe 17 are welded together in the circumferential direction.

As described above, since slits are not formed in the ends of the first pipe 15 and one end of the second pipe 17, the shapes of the pipe ends are maintained, and welding can be performed in the circumferential direction without problems.

In addition, when considering the thermal effect on the outer joint pipe 9 when fixing the second pipe 17 to the outer peripheral surface of the steel pipe body 3, the second pipe 17 is partially welded to the steel pipe body 3 (also referred to as assembly welding). You can fix it by In this case, if the distance a (see FIG. 2(a)) in the first pipe mounting step S1 is within 500 mm and the length of the second pipe 17 is not excessively long, the mounting strength of the second pipe 17 can be ensured. Therefore, it is preferable.

<Slit communication process>
In the slit connecting step S9, after the second pipe attaching step S7, as shown in FIG. This is a step of connecting the
By connecting the first slit 15a and the second slit 17a, the joint pipe 7 composed of the first pipe 15 and the second pipe 17 and provided with the slit 7a over the entire length is formed.

FIG. 2 shows an example of manufacturing the steel pipe sheet pile 1 having the outer joint pipe 9 at the end of the steel pipe body 3, but when manufacturing the steel pipe sheet pile 1 having the inner joint pipe 11 at the end of the steel pipe body 3 do the same for
However, in the case of the steel pipe sheet pile 1 having the inner joint pipe 11, the length of the second pipe 17 attached in the second pipe attaching step S7 is the length of the portion of the inner joint pipe 11 where the thread is not formed, specifically the inner joint pipe When the outer joint pipe 9 is fitted to 11 (see FIG. 3), the length extends from the portion where the pipe end of the outer joint pipe 9 abuts to the end of the first pipe 15 .

As described above, in the present embodiment, before the mechanical joint pipe 5 is attached to the steel pipe body 3, the first pipe 15 is attached and the first slit 15a is formed. Heat during the process and redistribution of stress when forming the first slit 15 a do not affect the roundness of the mechanical joint pipe 5 .
In addition, the second pipe 17 is also provided with a second slit 17a in advance, and is fixed to the steel pipe body 3 and welded to the first pipe 15. Small impact.

As described above, according to the present invention, the thermal effect during installation of the joint pipe 7 and the effect during slitting are minimized. The steel pipe sheet pile 1 having the joint pipe 7 on the outer peripheral surface can be manufactured while ensuring the circularity of the mechanical joint pipe 5 . Therefore, the fitability of the mechanical joint pipe 5 is ensured, and the attachment of the joint pipe 7 is not required during construction at the site, which contributes to labor saving and labor saving.

In the above-described embodiment, the screw-type mechanical joint pipe 5 has been described as an example, but the present invention is not limited to this, and effects can be obtained for other types of mechanical joint pipes. can be done. For example, in the case of a plug-in mechanical joint pipe in which the inner joint pipe is inserted into the outer joint pipe and the concave portion provided on the outer joint pipe and the convex portion provided on the inner joint pipe are engaged and connected, By applying the present invention, it is possible to manufacture steel pipe sheet piles with excellent workability on site.

Moreover, the present invention can be applied to both a steel pipe body having a mechanical joint pipe at one end and a steel pipe body having mechanical joint pipes at both ends. That is, when connecting a plurality of steel pipe sheet piles in the vertical direction, one that is placed at the top or bottom stage and has mechanical joint pipes only at the lower end or upper end of the steel pipe body, and one that is placed in the middle and has mechanical joint pipes at both ends of the steel pipe body The present invention can be applied to steel pipe sheet piles having joint pipes and steel pipe sheet piles in any case.

A specific experiment was conducted to confirm the effects of the method for manufacturing the steel pipe sheet pile 1 of the present invention, and the results will be described below.
A steel pipe body 3 having an outer diameter of 1000 mm and a plate thickness of 12 mm was used.
The joint pipe 7 or the first pipe 15 and the second pipe 17 constituting the joint pipe 7 had an outer diameter of 165.2 mm and a plate thickness of 11 mm.

As an invention example, a steel pipe sheet pile 1 was manufactured using the manufacturing method in the embodiment described in FIGS. In the example of the present invention, the distance a=300 mm, the distance b=80 mm, and the distance c=80 mm (see FIG. 2).

Further, as Comparative Examples 1 and 2, steel pipe sheet piles 19 and 21 were manufactured in a procedure different from the manufacturing method shown in FIG.
The manufacturing method in Comparative Example 1 is shown in FIG. FIG. 5, like FIG. 2, illustrates the case where the outer joint pipe 9 is provided at the end of the steel pipe body 3 (the same applies to FIG. 6 below).

In Comparative Example 1, first, as shown in FIG. 5(a), the outer joint pipe 9 was attached to the end portion of the steel pipe body 3 by all-around welding.
Next, as shown in FIG. 5B, the joint pipe 7 was attached to the outer peripheral surface of the outer joint pipe 9 and the steel pipe body 3 . At this time, the outer joint pipe 9 was not welded, and the portion of 300 mm from the end of the steel pipe body 3 indicated by the arrow in the drawing was partially welded, and the other portion was full-length welded.
Next, as shown in FIG. 5(c), a slit 7a was formed along the entire length of the joint pipe 7 attached in FIG. 5(b), and a steel pipe sheet pile 19 was manufactured. A steel pipe sheet pile 19 having an inner joint pipe 11 was similarly manufactured.

The manufacturing method in Comparative Example 2 is shown in FIG.
In Comparative Example 2, first, as shown in FIG. 6A, the outer joint pipe 9 was attached to the end portion of the steel pipe body 3 by all-around welding.
Next, as shown in FIG. 6(b), a first pipe 15, which will be a part of the joint pipe 7, was attached to the outer peripheral surface of the steel pipe body 3 at a distance of 300 mm from the end of the steel pipe body 3 by full-length welding.
Next, as shown in FIG. 6(c), a first slit 15a was formed in a portion excluding the end of the first pipe 15 attached in FIG. 6(b). The distance between the end of the first pipe 15 and the first slit 15a was set to 80 mm.

Next, as shown in FIG. 6(d), the second pipe 17 that constitutes the joint pipe 7 together with the first pipe 15 was attached. A second slit 17a is provided in advance in the second pipe 17 except for one end, and the distance between the end of the second pipe 17 and the second slit 17a is set to 80 mm.
The second pipe 17 was attached by the same method as described in FIG. 2(d), and partial welding was used to fix the second pipe 17 to the steel pipe body 3.
Next, as shown in FIG. 6(e), the joint pipe 7 composed of the first pipe 15 and the second pipe 17 is formed by connecting the first slit 15a and the second slit 17a, and the steel pipe sheet pile 21 is formed. manufactured. A steel pipe sheet pile 21 having an inner joint pipe 11 was similarly manufactured.

For the steel pipe sheet pile 1 manufactured using the above invention example and the steel pipe sheet piles 19 and 21 manufactured using Comparative Examples 1 and 2, the circularity (maximum outer diameter - minimum outer diameter) of the mechanical joint pipe 5 was calculated. and the comparison is shown in FIG. FIG. 7 shows the circularity ratio normalized by the circularity of Comparative Example 2. As shown in FIG.
As shown in the graph of FIG. 7, the roundness ratio of the steel pipe sheet pile 1 in the example of the present invention was significantly smaller than those of Comparative Examples 1 and 2, and was reduced by 75% compared to that of Comparative Example 2.

This is because, in Comparative Examples 1 and 2, the mechanical joint pipe 5 is attached to the steel pipe body 3, and then the joint pipe 7 or the first pipe 15 is attached and slit processing is performed, whereas in the invention example, the first Since the mechanical joint pipe 5 is attached after the pipe 15 is attached to form the first slit 15a, the mechanical joint pipe 5 is affected by the heat effect during welding of the first pipe 15 and stress redistribution during slit processing. This is because it did not affect

In addition, in the steel pipe sheet piles 19 and 21 manufactured by the manufacturing methods of Comparative Examples 1 and 2, when connecting the upper and lower steel pipe sheet piles 19 and 21, the upper steel pipe sheet piles 19 and 21 cannot be rotated only by human power, Auxiliary jigs such as chain blocks and chill holes were required.
On the other hand, the steel pipe sheet pile 1 manufactured by the manufacturing method of the example of the present invention has a good degree of fit with the mechanical joint pipe 5 because the roundness is ensured. The steel pipe sheet pile 1 could be rotated, and the workability was improved compared to Comparative Examples 1 and 2.

From the results of the above examples, it is obvious that in the production of steel pipe sheet piles, the order of installation of mechanical joint pipes, installation of joint pipes, and formation of slits affects the roundness and compatibility of mechanical joint pipes. is.
According to the present invention, the outer circumferences of the steel pipe main body and the mechanical joint pipe are sufficiently secured by minimizing the thermal effect during installation of the joint pipe and the effect during slit processing to sufficiently ensure the fitability of the mechanical joint pipe. Steel pipe sheet piles can be manufactured with joint pipes on the faces.

1 steel pipe sheet pile 3 steel pipe main body 5 mechanical joint pipe 7 joint pipe 7a slit 9 outer joint pipe 9a tap hole 11 inner joint pipe 11a tap hole 13 anti-rotation bolt 15 first pipe 15a first slit 17 second pipe 17a second slit 19 Steel pipe sheet pile (Comparative example 1)
21 Steel pipe sheet pile (Comparative example 2)
23 Steel pipe sheet pile (conventional example)

Claims (2)

A method for manufacturing a steel pipe sheet pile having a mechanical joint pipe at the end of a steel pipe body and a joint pipe extending in the pipe axial direction on the outer peripheral surface of the steel pipe body and the mechanical joint pipe,
a first pipe attaching step of attaching, by welding, a first pipe to be a part of the joint pipe to the outer peripheral surface of the steel pipe body at a distance of 200 mm or more from the end of the steel pipe body;
After the first pipe attaching step, a first slit forming step of forming a first slit extending in the pipe axial direction in a portion of the first pipe excluding the end portion;
After the first slit forming step, a mechanical joint pipe attaching step of attaching the mechanical joint pipe to the end portion of the steel pipe body;
After the mechanical joint pipe mounting step, a second pipe, which is previously provided with a second slit extending in the pipe axial direction in a portion other than one end portion and which constitutes the joint pipe together with the first pipe, is attached to the first pipe. The steel pipe body is fixed to the outer peripheral surface of the steel pipe main body so that the second slit is positioned on the same axis as the first slit of the first pipe, and the first slit is brought into contact with the end of the first pipe. a second pipe attaching step of welding an end of a pipe and one end of the second pipe;
After the second pipe attaching step, a slit communicating step of forming slits in the end portions of the first pipe and the second pipe to communicate the first slit and the second slit. A method for manufacturing a steel pipe sheet pile having a mechanical joint pipe. In the first pipe mounting step, the first pipe is arranged so that the end thereof is located within 500 mm from the end of the steel pipe body,
2. The method for manufacturing a steel pipe sheet pile having a mechanical joint pipe according to claim 1, wherein said second pipe is fixed to said steel pipe body by partial welding in said second pipe mounting step.

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