Joint structure

Abstract

The present invention provides a joint structure that enables increased resistance to bending moments at the connection point of a steel pipe. [Solution] In one embodiment of the joint structure 10, the inner joint pipe 18 of one steel pipe 14 is fitted into the outer joint pipe 16 of one steel pipe 12, a pin member 32 is inserted from the outer through hole 22 side of the outer joint pipe 16 to the inner through hole 24 side of the inner joint pipe 18, and a bolt B is screwed through the hole in the pin member 32 into the inner female thread member 28 of the inner joint pipe 18, thereby connecting the steel pipes. The structure includes an outer support member 40 provided on the outside of the outer through hole of the outer joint pipe 16 so as to surround the outer through hole and has a hole into which the pin member is fitted, and an inner support member 44 provided on the inside of the inner through hole of the inner joint pipe 18 and on the outside of the female thread member so as to surround the inner through hole and has a hole into which the pin member is fitted.

Description

Technical Field

[0001] The present disclosure relates to a joint structure for connecting steel pipes used, for example, in steel pipe piles, steel sheet piles, steel pipes for pipe roof methods, building columns, water pipes, etc.

Background Art

[0002] Conventionally, in the construction of long steel pipe piles, steel sheet piles, etc., due to transportation and manufacturing convenience, steel pipes of fixed lengths are carried into the construction site, and each steel pipe is connected by welding at the construction site to obtain the desired length.

[0003] However, such connection work by welding requires skilled techniques and strict construction management regarding ensuring working conditions such as climate conditions and quality control of the welded parts. Furthermore, the proportion of time spent on such welding work in the construction time is large, causing a long construction period.

[0004] On-site, various joint structures for mechanically connecting steel pipes using bolts, etc. have been proposed. For example, Patent Document 1 attaches an outer joint pipe to the end of one steel pipe to be connected, and attaches an inner joint pipe that fits into the hollow part of the aforementioned outer joint pipe to the end of the other steel pipe, and discloses a joint structure having a configuration in which the inner joint pipe is fitted into the hollow part of the outer joint pipe to connect the steel pipes. A coupling pin is inserted into the pin holes of both joint pipes with their centers aligned. The pin is a pinned pin having a flange portion that abuts against the outer peripheral surface of the outer joint pipe at its outer end, and a bolt through-hole penetrates through its central portion. This pin is inserted from the pin hole of the outer joint pipe into the pin hole of the inner joint pipe until its tip surface makes surface contact with the outer surface of a female screw member provided on the inner joint pipe. Then, a retaining bolt is inserted into the aforementioned bolt through-hole of the pin and screwed into the screw hole of the aforementioned female screw member to fix the pin, thereby coupling the fitting state of the outer joint pipe and the inner joint pipe and achieving the connection of the steel pipes.

Prior Art Documents

[0005] [Patent Document 1] Patent No. 5762853 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Incidentally, in recent years, bridges, offshore wind power generation facilities, and other structures have tended to become larger, and the forces acting on their steel pipes tend to become stronger. Therefore, it is desirable to further increase the resistance to bending moments at the connections of steel pipes.

[0007] The present disclosure aims to provide a joint structure that enables increased resistance to bending moment at the connection point of a steel pipe. [Means for solving the problem]

[0008] One aspect relating to this disclosure is, In a joint structure that connects steel pipes by fitting the inner joint pipe of one end of one steel pipe into the outer joint pipe of the other end of one steel pipe, inserting a pin member from the outer through-hole side of the outer joint pipe to the inner through-hole side of the inner joint pipe, and screwing a bolt through the bolt hole of the pin member into the inner female thread member of the inner joint pipe, An outer support member is provided on the outside of the outer through-hole of the outer joint pipe so as to surround the periphery of the outer through-hole and has a hole into which the pin member is fitted, An inner support member is provided on the inside of the inner through-hole of the inner joint pipe and on the outside of the female thread member, surrounding the periphery of the inner through-hole, and having a hole into which the pin member is fitted. Joint structure equipped with To provide.

[0009] According to the joint structure described above, by providing an outer support member and an inner support member, the resistance to bending moment around the pin member can be further increased. Therefore, this joint structure can increase the resistance to bending moment at the connection point of the steel pipe.

[0010] Preferably, the outer support member is in contact with the outer joint pipe, and the inner support member is in contact with the inner joint pipe and the female thread member. With this configuration, the resistance to bending moment around the pin member can be further increased simply by adding the outer support member and the inner support member.

[0011] Preferably, the pin member has a tip surface located at one end and a radial projection located at the other end in the axial direction of the pin member. In this case, when connecting the steel pipes, the pin member is inserted from the outer through-hole side to the inner through-hole side until the radial projection abuts against the outer support member. This configuration allows the radial projection to press the outer support member against the outer joint pipe, and allows the outer support member to suitably receive the bending moment around the outer joint pipe.

[0012] Preferably, the pin member has a tip surface located at one end and a radial projection located at the other end in the axial direction of the pin member. In this case, when connecting the steel pipes, the pin member is inserted from the outer through-hole side to the inner through-hole side until the tip surface of the pin member abuts against the female thread member. With this configuration, the fitting holes, including the outer and inner through-holes, can be filled with the pin member, thereby sufficiently increasing the strength of the pin member or fitting holes, and furthermore, the inner support member can suitably receive the bending moment around the inner joint pipe.

[0013] Preferably, the pin member has a tip surface located at one end and a radially protruding portion located at the other end in the axial direction of the pin member. In this case, the bolt preferably has a head that contacts the pin member in the axial direction of the pin member when connecting the steel pipes and a male threaded portion that can be screwed into the female threaded member. With this configuration, the outer support member and the inner support member can be firmly held between the radially protruding portion of the pin member and the female threaded member, and thus the outer joint pipe and the inner joint pipe can be more firmly held and fixed by the outer support member and the inner support member. [Effects of the Invention]

[0014] According to the joint structure of the above embodiment, since it has the above configuration, the resistance to bending moment at the connection part of the steel pipe can be suitably increased. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 shows an example of steel pipes connected using a joint structure according to one embodiment, where (a) is a top view and (b) is a front view. [Figure 2] Figure 2 shows a cross-sectional view of the steel pipe along line II-II in Figure 1(b). [Figure 3] Figure 3 is a cross-sectional view illustrating the connection of steel pipe members in the steel pipe shown in Figure 1, showing the case where the outer joint pipe of one steel pipe member and the inner joint pipe of the other steel pipe member are at separate locations. [Figure 4] Figure 4 is a cross-sectional view illustrating the connection of steel pipe members in the steel pipe shown in Figure 1, where the outer joint pipe of one steel pipe member and the inner joint pipe of the other steel pipe member are in their predetermined positions, and the pin members, which are connecting members, are not yet attached. [Figure 5] Figure 5 is a cross-sectional view illustrating the connection of steel pipe members in the steel pipe shown in Figure 1, showing the outer joint pipe of one steel pipe member and the inner joint pipe of the other steel pipe member in predetermined positions, and showing the state in which the connecting pin member is being inserted. [Figure 6]FIG. 6 is a cross-sectional view for explaining the connection of steel pipe materials in the steel pipe shown in FIG. 1, showing a state in which an outer joint pipe of one steel pipe material and an inner joint pipe of the other steel pipe material are in a predetermined position and a pin member as a connecting member is inserted. [Figure 7] FIG. 7 is a cross-sectional view for explaining the connection of steel pipe materials in the steel pipe shown in FIG. 1, showing a completed connection state in which an outer joint pipe of one steel pipe material and an inner joint pipe of the other steel pipe material are in a predetermined position and a pin member as a connecting member is inserted and bolted. [Figure 8] FIG. 8 is an enlarged view of part VIII in FIG. 2. [Figure 9] FIG. 9 is a diagram showing the FEM analysis result of the joint structure according to an embodiment.

MODE FOR CARRYING OUT THE INVENTION

[0016] Hereinafter, the joint structure according to an embodiment of the present disclosure will be described based on the drawings.

[0017] FIGS. 1(a) and (b) show a steel pipe 1 connected using a joint structure 10 according to an embodiment, and FIG. 2 shows a cross-sectional view of the steel pipe 1 along line II-II in FIG. 1(b). However, the line II-II in FIG. 1(b) extends so as to include the pipe axis of the steel pipe 1. FIGS. 3 to 7 are cross-sectional views for explaining the flow of connection at the connection portion of the steel pipe 1 in FIG. 1, showing the joint structure 10, the joint J, or the periphery of the corresponding portions in the same cross-section as FIG. 2. FIG. 8 is an enlarged view of part VIII in FIG. 2 of the steel pipe 1. The steel pipe 1 described here can be used for steel pipe piles, steel pipe sheet piles, etc. or a part thereof.

[0018] The steel pipe 1 is manufactured by connecting steel pipe materials 12 and 14. Each of the steel pipe materials 12 and 14 is a steel pipe formed in a cylindrical shape from steel. The steel pipe materials 12 and 14 are connected to each other by a joint, that is, a joint J. The joint structure 10 is applied to this joint J.

[0019] As shown in Figure 2, the joint J comprises an outer joint pipe 16 fixed to one end of one steel pipe material 12 and an inner joint pipe 18 fixed to one end of the other steel pipe material 14. The outer joint pipe 16 is fixed to the steel pipe material 12 by welding, and the inner joint pipe 18 is fixed to the steel pipe material 14 by welding via a flange member 20.

[0020] As shown in Figures 3 to 7, the flange member 20 has a constant thickness in the direction along the pipe axis A1 (hereinafter referred to as the pipe axis direction), and is formed in an annular shape with an outer diameter approximately the same as the outer diameter of the steel pipe material 14 and an inner diameter smaller than the inner diameter of the steel pipe material 14. The annular outer circumference of one end face of the flange member 20 is welded to the end face of the steel pipe material 14, and the inner edge side portion is fixed in a state where it protrudes radially inward from the steel pipe material 14, and the inner joint pipe 18 is fixed to the other end face by welding.

[0021] The end face 20a of the flange member 20 on the joint pipe side is designed as a stopper, and is configured so that the tip 16a of the mating outer joint pipe 16 can abut against it. The end face 20a on the joint pipe side is formed as an annular recess so that the tip 16a of the outer joint pipe 16 can fit into it, but is not limited to this.

[0022] On the other hand, an annular stopper member 21 is fixed to the inner surface of the outer joint pipe 16 by welding or the like. The stopper member 21 is provided so that the tip 18a of the inner joint pipe 18 is stopped against it. Furthermore, a fitting groove may be formed in the tip 18a of the inner joint pipe 18 into which the outer surface 21a of the stopper member 21 is fitted. This further enhances the watertightness of the joint structure 10 of the joint J. Note that although the stopper member 21 has a circular cross-section here, it may have other cross-sectional shapes.

[0023] The steel pipes 12 and 14 are movable relative to each other, and therefore the outer joint pipe 16 and the inner joint pipe 18 are movable relative to each other. Both joint pipes 16 and 18 are cylindrical in shape. Both joint pipes 16 and 18 are movable relative to each other in the axial direction along the pipe axis A1, in the circumferential direction around the pipe axis A1, and / or in the radial direction centered on the pipe axis A1, so that the inner joint pipe 18 can be fitted into the hollow part of the outer joint pipe 16, and the outer joint pipe 16 and the inner joint pipe 18 can be positioned in predetermined positions. When the joint members 16 and 18 are in predetermined positions, the tip portion 16a of the outer joint pipe 16 should abut against the joint pipe side end face 20a of the flange member 20. Also, when the joint members 16 and 18 are in predetermined positions, the tip portion 18a of the inner joint pipe 18 should abut against the outer surface portion 21a of the stopper member 21.

[0024] As shown in Figure 3, the outer joint pipe 16 is formed in a cylindrical shape, i.e., a tube shape, from steel or the like, as described above, and has a tapered fitting widening portion 16b on its inner circumference that widens as it moves toward the inner joint pipe 18 in the pipe axis direction. On the other hand, the inner joint pipe 18 is formed in a cylindrical shape, i.e., a tube shape, from steel or the like, and has a tapered fitting narrowing portion 18b on its outer circumference that narrows in diameter as it moves toward the outer joint pipe 16 in the pipe axis direction. As shown in Figure 4, this fitting narrowing portion 18b is fitted into the fitting widening portion 16b, so that the outer joint pipe 16 and the inner joint pipe 18 are superimposed radially.

[0025] As shown in Figure 4, when the outer joint pipe 16 and the inner joint pipe 18 are superimposed and positioned in a predetermined location, the through hole 22 of the outer joint pipe 16 (hereinafter referred to as the outer through hole) 22 and the through hole 24 of the inner joint pipe 18 (hereinafter referred to as the inner through hole) 24 overlap in the superimposing direction, i.e., radially, and preferably their axes coincide and are continuous. This forms a fitting hole 26 including the outer through hole 22 and the inner through hole 24. The hole shapes of these holes 22, 24, and 26 are designed to be cylindrical with a constant inner diameter. For example, the outer through hole 22 may be referred to as the first pin hole, and the inner through hole 24 may be referred to as the second pin hole.

[0026] The outer joint pipe 16 is provided with a plurality of outer through holes 22 at equal intervals in the circumferential direction, and the inner joint pipe 18 is provided with a plurality of inner through holes 24 at equal intervals in the circumferential direction. When the outer joint pipe 16 and the inner joint pipe 18 are positioned in predetermined locations, each of the outer through holes 22 is continuous with the corresponding inner through hole 24. Here, the plurality of outer through holes 22 are located in the same pipe axis direction in the outer joint pipe 16 and are arranged at 45° intervals (=θ in Figure 1(a)) in the circumferential direction, and the plurality of inner through holes 24 are located in the same pipe axis direction in the inner joint pipe 18 and are similarly arranged at 45° intervals (=θ in Figure 1(a)) in the circumferential direction. Therefore, when the outer joint pipe 16 and the inner joint pipe 18 are positioned in predetermined locations, eight fitting holes 26 are formed, each including the outer through holes 22 and the inner through holes 24. Note that the number of fitting holes 26 formed in this way is not limited to eight, and the arrangement of the fitting holes 26 is not limited to 45° intervals. The number and arrangement of the fitting holes 26 should be determined according to the required strength of the steel pipe 1, steel pipe materials 12, and 14.

[0027] An internal thread member 28 is provided on the inner circumferential surface 18i side of the internal joint pipe 18, that is, on the opposite side of the internal joint pipe 18 from the external joint pipe 16 when the external joint pipe 16 and the internal joint pipe 18 are positioned in a predetermined location. The internal thread member 28 is a substantially circular plate-shaped member and is provided to close the internal through-hole 24 from the inside of the internal joint pipe 18. An internal thread hole 30 is formed in this internal thread member 28, penetrating in the direction of its plate thickness. This internal thread hole 30 has an inner diameter smaller than the inner diameters of the external through-hole 22 and the internal through-hole 24, respectively. The axis A2 of this internal thread hole 30 (see Figure 4) coincides with the axis of the internal through-hole 24. When the external joint pipe 16 and the internal joint pipe 18 are positioned in a predetermined location, the axis of the external through-hole 22 coincides with the axis of the internal through-hole 24 and the axis A2 of the internal thread hole 30. The female threaded member 28 is a member that functions like a nut having a female threaded hole 30, and may also be called a nut plate. The axis A2 of the female threaded hole 30 coincides with the axis 32A of the pin member 32 when the pin member 32 is fitted into the fitting hole 26, as will be described later.

[0028] A pin member 32 is used to connect the outer joint pipe 16 and the inner joint pipe 18. The pin member 32 is an example of a connecting member, and is substantially cylindrical in shape, having a radially protruding portion 34 and a fitting portion 36 that fits into the fitting hole 26. The fitting portion 36 is formed in a cylindrical shape here. The radially protruding portion 34 has a larger diameter than the fitting portion 36 and is disc-shaped. The axis 32A of the pin member 32 coincides with the axis of the radially protruding portion 34 and the axis of the fitting portion 36. In the direction of the axis 32A of the pin member 32, the radially protruding portion 34 and the fitting portion 36 are arranged in order. The end face of the radially protruding portion 34 in the direction of the axis 32A is the base end face 34a and is perpendicular to the axis 32A, and the end face of the fitting portion 36 in the direction of the axis 32A is the tip face 36a and is perpendicular to the axis 32A. The pin member 32 is used to connect the pipe members 12 and 14 by fitting the fitting portion 36 into the fitting hole 26. At that time, the radially protruding portion 34 that extends radially around the entire circumference of the fitting portion 36 functions as a flange that abuts against the outer support member 40, which will be described later in this embodiment. Thus, the pin member 32 is a so-called flanged pin. The pin member 32 has a through hole (hereinafter referred to as the pin body hole) 38 that extends along its axis 32A. The pin body hole 38 is a bolt hole and opens on the base end face 34a and the tip end face 36a, respectively. A bolt B is inserted into the pin body hole 38.

[0029] Furthermore, the joint structure 10 includes an outer support member 40 and an inner support member 44.

[0030] The outer support member 40 is provided on the outside of the outer through-hole 22 of the outer joint pipe 16, surrounding the periphery of the outer through-hole 22. The outer support member 40 is provided as a doubling plate. The outer support member 40 is a substantially circular plate-shaped member and has a shape corresponding to the curved shape of the outer circumferential surface 16o of the outer joint pipe 16. The outer support member 40 is provided on the outer circumferential surface 16o of the outer joint pipe 16 by welding. The outer support member 40 has a through-hole (hereinafter referred to as an outer expansion hole) 42 that is continuous with the outer through-hole 22. The outer expansion hole 42 overlaps with the outer through-hole 22 in the overlapping direction, i.e., in the radial direction, and their axes coincide and are continuous. The outer expansion hole 42 has the same inner diameter as the outer through-hole 22, and is designed to be cylindrical with a constant inner diameter.

[0031] The inner support member 44 is provided inside the inner through-hole 24 of the inner joint pipe 18, surrounding the periphery of the inner through-hole 24. The inner support member 44 is provided as a doubling plate. The inner support member 44 is a substantially circular plate-shaped member and has a shape corresponding to the curved shape of the inner circumferential surface 18i of the inner joint pipe 18. The inner support member 44 is provided on the inner circumferential surface 18i of the inner joint pipe 18 by welding. The inner support member 44 is welded to each of the inner joint pipe 18 and the female thread member 28 so as to be sandwiched between them. The inner support member 44 has a through-hole (hereinafter referred to as an inner expansion hole) 46 that is continuous with the inner through-hole 24. The inner expansion hole 46 overlaps with the inner through-hole 24 in the overlapping direction, i.e., in the radial direction, and their axes coincide and are continuous. The inner expansion hole 46 has the same inner diameter as the inner through-hole 24, and is designed to be cylindrical with a constant inner diameter. The inner expansion hole 46, which is continuous with the inner through hole 24, is covered with the aforementioned female thread member 28. A stepped portion 28s is provided on the female thread member 28 for positioning or attaching the female thread member 28 to the inner support member 44 (see Figure 8).

[0032] Therefore, the fitting hole 26, which includes the outer through hole 22 and the inner through hole 24, is expanded to the outer expansion hole 42 of the outer support member 40, and also to the inner expansion hole 46 of the inner expansion hole 46. The fitting portion 36 of the pin member 32 is fitted into the expanded fitting hole 26. The fitting portion 36 is designed to fit snugly into the expanded fitting hole 26, preferably without any play. When fitting the pin member 32 into the fitting hole 26, it is preferable that the pin member 32 is inserted until the inner surface 34b of the radially protruding portion 34 abuts against the outer surface 40o of the outer support member 40 (see Figure 8). Also, when fitting the pin member 32 into the fitting hole 26, it is preferable that the pin member 32 is inserted until the tip surface 36a of the fitting portion 36 abuts against the outer surface 28a of the female screw member 28 (see Figure 8).

[0033] When the pin member 32 is fitted into the fitting hole 26, the bolt B is inserted into the pin body hole 38 of the pin member 32, and the male threaded portion BS of the bolt B is screwed into the female threaded hole 30 of the female threaded member 28, thereby connecting the outer joint pipe 16 and the inner joint pipe 18, and thus connecting the steel pipe materials 12 and 14.

[0034] Next, a method for connecting steel pipes 12 and 14 using such a joint structure 10 will be described.

[0035] To connect the two steel pipes 12 and 14, first, the two joint pipes 16 and 18 are moved relative to each other in the axial direction of the pipes, taking into consideration the positions of the through holes 22 and 24, and the inner joint pipe 18 is fitted into the outer joint pipe 16.

[0036] At this time, as shown in Figures 3 and 4, the outer diameter of the narrowed-diameter fitting portion 18b of the inner joint pipe 18 is smaller than the inner diameter of the widened fitting portion 16b of the outer joint pipe 16 at the tip portion 16a. Therefore, the inner joint pipe 18 can be easily inserted into the outer joint pipe 16. After insertion, the tip portion 16a can slide toward a position where it contacts the joint pipe side end face 20a of the flange member 20, while being guided by each other. Similarly, at this time, the tip portion 18a of the inner joint pipe 18 can slide toward a position where it contacts the outer surface portion 21a of the stopper member 21.

[0037] Then, as shown in Figures 5 and 6, the pin member 32 is inserted into the fitting hole 26 formed by through holes 22, 24, 42, and 46 that are continuous in the overlapping direction, in this case in the radial direction. After that, as shown in Figure 7, the bolt B is inserted into the pin body hole 38 of the pin member 32 and screwed into the female thread hole 30 of the female thread member 28. This allows the two connecting pipes 16 and 18 to be connected.

[0038] The following describes some of the features and effects of the joint structure 10 having the above configuration.

[0039] The joint structure 10 is a joint structure that connects steel pipes 12 and 14 by fitting the inner joint pipe 18 at the end of one steel pipe 14 into the outer joint pipe 16 at the end of one steel pipe 12, inserting a pin member 32 from the outer through hole 22 side of the outer joint pipe 16 to the inner through hole 24 side of the inner joint pipe 18, and screwing a bolt B through the pin body hole 38, which is a bolt through hole in the pin member 32, into the inner female thread member 28 of the inner joint pipe 18. This joint structure 10 further includes an outer support member 40 and an inner support member 44. The outer support member 40 is provided so as to surround the outside of the outer through hole 22 of the outer joint pipe 16 and has an outer expansion hole 42 into which the pin member 32 is fitted. The inner support member 44 is provided inside the inner through-hole 24 of the inner joint pipe 18 and outside the female thread member 28, surrounding the inner through-hole 24, and has an inner expansion hole 46 into which the pin member 32 is fitted. With this joint structure 10 configuration, by providing the outer support member 40 and the inner support member 44, the resistance to bending moment around the pin member 32 can be further increased. Therefore, with the joint structure 10, the resistance to bending moment can be increased at the connection part of the steel pipe materials 12 and 14, which are steel pipes, respectively.

[0040] The outer support member 40 is in contact with the outer joint pipe 16, and the inner support member 44 is in contact with the inner joint pipe 18 and the female thread member 32. With this configuration, simply by providing the outer support member 40 and the inner support member 44, the resistance to bending moment around the pin member 32 can be further increased.

[0041] Furthermore, the pin member 32 has a tip surface 36a located at one end in the direction of the axis 32A of the pin member 32, and a radially protruding portion 34 located at the other end. Preferably, when connecting the steel pipe materials 12 and 14, the pin member 32 is inserted from the outer through hole 22 side to the inner through hole 24 side until the radially protruding portion 34 abuts against the outer support member 40. With this configuration, the radially protruding portion 34 can press the outer support member 40 against the outer joint pipe 16, thereby allowing the outer support member 40 to suitably receive the bending moment around the outer joint pipe 16.

[0042] Furthermore, when connecting the steel pipes 12 and 14, preferably, the pin member 32 is inserted from the outer through hole 22 side to the inner through hole 24 side until the tip surface 36a of the pin member 32 abuts against the outer surface 28a of the female thread member 28. This configuration allows the fitting hole 26 to be sufficiently filled with the pin member 32, thereby significantly increasing the strength of the hole. This configuration also allows the inner support member 44 to effectively receive the bending moment around the inner joint pipe 18.

[0043] The bolt B has a head BH that contacts the base end face 34a, which is the outer surface of the pin member 32 in the axial direction of the pin member 32, when connecting the steel pipe materials 12 and 14, and a male threaded portion BS that can be screwed into the female threaded member 28. With this configuration, the outer support member 40 to the inner support member 44 can be firmly held between the radially protruding portion 34 of the pin member 32 and the female threaded member 28, and thus the outer joint pipe 16 and the inner joint pipe 18 can be more firmly held and fixed by the outer support member 40 and the inner support member 44.

[0044] Here, in order to investigate the stress distribution when a force acting in a direction that separates the steel pipes 12 and 14 is applied around one of the pin members 32 of the joint structure 10 described above, FEM analysis was performed using a computer model. The results are shown in Figure 9. In this experiment, the outer joint pipe 16 was fixed, and a force was applied to the inner joint pipe 18 in the direction of the pipe axis that separates the inner joint pipe 18 from the outer joint pipe 16. As a result, as shown in Figure 9, areas (dense areas) where strong stress is applied to the outer support member 40 and the inner support member 44 were created, confirming that the stress can be suitably distributed. In this way, by providing the outer support member 40 and the inner support member 44, the stress acting around them, i.e., the bending moment, can be suitably distributed, and thus the resistance to the bending moment at the connection part of the steel pipes 12 and 14 can be increased. Note that in Figure 9, the parts corresponding to the above components are similarly denoted by the above reference numerals for ease of understanding.

[0045] While representative embodiments of this disclosure have been described above, this disclosure is not limited thereto, and various modifications are possible. Various substitutions and modifications are permitted as long as they do not deviate from the spirit and scope of this disclosure as defined by the claims of this application. [Explanation of Symbols]

[0046] 1 Steel pipe 10 Joint structure 12, 14 Steel pipe material (steel pipe) 16. Outer joint pipe 18. Internal fitting pipe 22 Outer through hole 24 Inner through hole 26 mounting holes 28 Female threaded member 30 female screw holes 32 Pin component 34 Radial overhang 36 Insertion part 40 Outer support member 42 Outer expansion hole 44 Inner support member 46 Internal expansion holes B bolt

Claims

1. In a joint structure that connects steel pipes by fitting the inner joint pipe of one end of one steel pipe into the outer joint pipe of the other end of one steel pipe, inserting a pin member from the outer through-hole side of the outer joint pipe to the inner through-hole side of the inner joint pipe, and screwing a bolt through the bolt hole of the pin member into the inner female thread member of the inner joint pipe, An outer support member is provided on the outside of the outer through-hole of the outer joint pipe so as to surround the periphery of the outer through-hole and has a hole into which the pin member is fitted, An inner support member is provided on the inside of the inner through-hole of the inner joint pipe and on the outside of the female thread member, surrounding the periphery of the inner through-hole, and having a hole into which the pin member is fitted. A joint structure equipped with [a specific feature].

2. The outer support member is in contact with the outer joint pipe, The inner support member is in contact with the inner joint pipe and also in contact with the female thread member. The joint structure according to claim 1.

3. The pin member has a tip surface located at one end and a radially protruding portion located at the other end in the axial direction of the pin member. When connecting the steel pipes, the pin member is inserted from the outer through-hole side to the inner through-hole side until the radially protruding portion abuts against the outer support member. The joint structure according to claim 1 or 2.

4. The pin member has a tip surface located at one end and a radially protruding portion located at the other end in the axial direction of the pin member. When connecting the steel pipes, the pin member is inserted from the outer through-hole side to the inner through-hole side until its tip surface abuts against the female thread member. The joint structure according to claim 1 or 2.

5. The pin member has a tip surface located at one end and a radially protruding portion located at the other end in the axial direction of the pin member. The bolt has a head that contacts the pin member in the axial direction of the pin member when connecting the steel pipes, and a male threaded portion that can be screwed into the female threaded member. The joint structure according to claim 1 or 2.

Images