JP4863783B2 - Steel pipe joint structure and steel pipe joining method - Google Patents

Description

  The present invention relates to a steel pipe joint structure and a steel pipe joining method, and more particularly to a steel pipe joint structure and a steel pipe joining method capable of butt welding a structural steel pipe of a steel structure building at an arbitrary angle. Is.

  As a conventional welding method for butt welding structural steel pipes, various methods such as a stepping method, a backing plate slide method, a backing plate metal touch method, and a backing plate projecting method are known. As an improvement of this type of welding method, the end plate is fixed flush with each small face of the steel pipe to be joined, and an annular steel intermediate member is inserted between the end plates to form a welding gap. JP-A-8-239909 (Patent Document 1) discloses a welding method for butt-welding a small end surface of a steel pipe.

  Any of these conventional welding methods is used when joining steel pipes with axial cores in a straight pipe form. However, when joining steel pipes whose shaft cores are relatively inclined, the small end surfaces of the steel pipes are cut in a direction inclined with respect to the axial center of the steel pipe, and an elliptical small end surface is formed in the joint portion. . For this reason, it is difficult to insert the backing plate, the backing steel pipe, etc. into the small edge portion of the steel pipe, and it is also difficult to accurately inscribe the backing plate etc. against the inner peripheral surface of the small edge portion. Butt welding between steel pipes has to depend on advanced steel pipe cutting skills and steel pipe welding skills of welding experts, or expensive cast steel truss nodes have to be used.

As a steel structure that requires butt welding between steel pipes having relatively inclined shaft cores, a dome having a single-layer lattice structure is exemplified. The single-layer lattice dome is to rigidly join steel pipes constituting a lattice member by welding to simultaneously achieve high rigidity and light weight of the steel structure frame. This kind of single-layer lattice dome has a relatively small amount of steel and the number of joints compared to a steel structure frame of the same scale multi-layer truss structure, and is advantageous from the viewpoint of construction cost reduction, shortening the construction period, etc. In recent years, it has attracted much attention as a roof structure for large spaces such as stadiums because of its excellent design freedom in daylighting and shading and effective use of internal space.
JP-A-8-239909

  In such a single-layer lattice structure, steel pipes oriented in an arbitrary direction must be joined at a joint portion. Especially for medium- or large-scale single-layer lattice structures, such a joint structure must be applied everywhere, so that it depends on advanced steel pipe cutting skills and steel pipe welding skills of welding experts etc. That is difficult in reality. For this reason, a method of welding a steel pipe to a truss node using a special and dedicated joint member such as a cast steel truss node has been generally adopted.

  However, the use of this type of joint member not only increases the construction cost and lengthens the construction period, but also the appearance of the joint member has a relatively large influence on the design of the structure. Therefore, a steel pipe joint capable of butt welding a single-layer latticed steel pipe without using such a joint member and without depending on advanced steel pipe cutting skills and steel pipe welding skills of welding experts etc. Development of the structure was requested.

  The present invention has been made in view of such circumstances, and the object of the present invention is not to use a special and dedicated joint member such as a cast steel truss node, but also to an advanced welding expert. An object of the present invention is to provide a steel pipe joint structure and a steel pipe joining method capable of butt-welding the joint ends of steel pipes whose axis cores are relatively inclined without depending on the steel pipe cutting skill and the steel pipe welding skill.

As a result of earnest research to achieve the above object, the present inventor has paid attention to the fact that it has become possible to cut the end of a steel pipe with high precision by the development of recent three-dimensional laser cutting technology, The present invention has been achieved based on such findings. That is, the present invention
In the steel pipe joint structure for butt welding the joint ends of steel pipes whose axis is relatively inclined,
The fore end portion of the steel pipe constituting the end of the joint has a fore end surface having an inclination angle with respect to the central axis of the steel pipe, and the outer peripheral surface of the flat plate having a metal touch surface is partially in the opening of the end end portion. The outer peripheral surface of the flat plate has a contour in which a generatrix with respect to the metal touch surface is oriented substantially parallel to a central axis of the steel pipe and inscribed in the opening of the fore edge, the metal touch surface is A steel pipe joint structure is provided which is positioned at a position protruding from the small edge portion.

  According to the above-described configuration of the present invention, the generatrix end is formed such that the generatrix of the outer peripheral surface of the flat plate with respect to the metal touch surface is oriented substantially parallel to the central axis of the steel pipe, Inserted into the opening. The outer peripheral surface of the flat plate is only partially inserted into the joint end opening, and the metal touch surface is positioned at a position protruding from the joint end opening. By bringing the flat metal touch surface into surface contact with the metal touch surface of the member to be butt welded, a welding gap is formed around the flat plate portion protruding from the end opening. According to such a configuration, the flat plate is disposed at the joint end of the steel pipe whose axis is relatively inclined, and the metal touch surfaces are brought into surface contact with each other, so that the steel pipe joint ends are opposed to each other. A welding gap can be formed, and a welding backing can be formed on the root portion of the welding gap by a flat plate outer peripheral surface. Thus, according to the steel pipe joint structure of the above configuration, a special and dedicated joint member such as a cast steel truss node is not used, and it does not depend on advanced steel pipe cutting skills and steel pipe welding skills of welding experts etc. The joint ends of steel pipes whose shaft cores are relatively inclined can be butt welded.

The present invention also provides a steel pipe joint structure for butt welding the joint ends of steel pipes whose axis is relatively inclined.
The fore end portion of the steel pipe constituting the end of the joint has a fore end surface having an inclination angle with respect to the central axis of the steel pipe, and the outer peripheral surface of the flat plate having a metal touch surface is partially in the opening of the end end portion. Inserted into
The small edge portion and the flat plate have a positioning mechanism that restricts the relative position of the flat plate and the steel pipe when the flat plate is inserted into the opening of the small edge portion, and mechanically restricts the insertion position and relative rotation of the flat plate. Providing a characteristic steel pipe joint structure.

  According to the above configuration of the present invention, since the flat plate can be accurately positioned at the small edge portion of the steel pipe by the positioning mechanism, the flat plate positioning work is simplified and the work efficiency of the joining work is improved. In addition, the flat plate inserted in the opening of the steel pipe edge part is in surface contact with the metal touch surface of the other steel material to be welded, and a welding gap is formed around the flat plate part. Can be easily welded. Thus, according to the steel pipe joint structure having such a configuration, a special and dedicated joint member such as a cast steel truss node is not used, and it depends on advanced steel pipe cutting skills and steel pipe welding skills of welding experts and the like. It is possible to butt-weld the joint ends of steel pipes whose axis is relatively inclined.

The present invention further provides a steel pipe joint structure for butt welding the joint ends of steel pipes whose axis is relatively inclined.
The fore end portion of the steel pipe constituting the end of the joint has a fore end surface having an inclination angle with respect to the central axis of the steel pipe, and the outer peripheral surface of the flat plate having a metal touch surface is partially in the opening of the end end portion. Inserted into
The flat plate provides a steel pipe joint structure having a positioning mechanism for positioning a relative position of the metal touch surfaces facing each other.

  When joining relatively inclined steel pipes, it is difficult to accurately align the opposing metal touch surfaces. However, according to the above configuration of the present invention, the positioning of the metal touch surfaces can Since the positions can be accurately determined and the steel pipes can be butt-welded with high precision, the work efficiency of the steel pipe assembly work is improved. Further, by bringing the metal touch surface of the flat plate into surface contact with the metal touch surface of the member to be butt welded, a welding gap is formed around the flat plate portion, so that the end of the steel pipe can be relatively easily moved. Can be welded. Thus, according to the steel pipe joint structure having such a configuration, a special and dedicated joint member such as a cast steel truss node is not used, and it depends on advanced steel pipe cutting skills and steel pipe welding skills of welding experts and the like. It is possible to butt-weld the joint ends of steel pipes whose axis is relatively inclined.

From another point of view, the present invention provides a steel pipe joining method for butt welding the joint ends of steel pipes whose axis is relatively inclined.
Cutting the fore end surface forming an angle of inclination with respect to the central axis of the steel pipe to form the end part of the joint end,
The outer peripheral surface of a flat plate having a metal touch surface is partially inserted into the opening of the fore edge, the outer peripheral surface of the flat plate is inscribed in the opening of the fore edge, and the metal touch surface protrudes from the fore edge. To position,
The metal touch surface is brought into surface contact with the metal touch surface of a member to be butt welded, and a welding gap is formed by the protrusion of the metal touch surface, and a welding backing is rooted by the outer peripheral surface of the welding gap. A steel pipe joining method is provided.

The present invention is also a steel pipe joining method of butt welding the joint ends of steel pipes whose axis is relatively inclined.
Inserting a flat plate having a metal touch surface that is partially inserted into the opening of the fore end while cutting the fore end with an inclination angle with respect to the central axis of the steel pipe to form the end of the end of the end Forming a mechanical engagement element for regulating position and relative rotation in the flat plate and the fore edge,
When the flat plate is inserted into the opening of the small opening, the relative position of the flat plate and the steel pipe is determined by the mechanical engagement element, and the insertion position and the relative rotation of the flat plate are limited by the mechanical engagement element. A steel pipe joining method is provided.

The present invention further provides a steel pipe joining method for butt welding the joint ends of steel pipes whose axis is relatively inclined.
Cutting the fore end surface forming an angle of inclination with respect to the central axis of the steel pipe to form the end part of the joint end,
The outer peripheral surface of a flat plate having a metal touch surface is partially inserted into the opening of the fore edge, and a mechanical engagement element for positioning the relative position of the opposing metal touch surface is engaged with the flat plate. By this, the steel pipe joining method characterized by positioning the relative position of metal touch surfaces is provided.

  According to the steel pipe joint structure and the steel pipe joining method of the present invention, without using a special and dedicated joint member such as a cast steel truss node, it also depends on advanced steel pipe cutting skills and steel pipe welding skills such as welding experts. It is possible to butt-weld the joint ends of the steel pipes whose shaft cores are relatively inclined without doing so.

  According to a preferred embodiment of the present invention, the mechanical engagement element for restricting the insertion position and relative rotation of the flat plate is formed in the flat plate and the small plate portion as a small plate portion and a flat plate positioning mechanism, and the relative position of the flat plate and the steel pipe Is determined by a mechanical engagement element when the flat plate is inserted into the opening of the fore edge, and the insertion position and relative rotation of the flat plate are limited by the mechanical engagement element. For example, as a mechanical engagement element, a slit or a groove is formed in a small portion of a steel pipe, and similarly, as a mechanical engagement element, a protrusion or a tenon is formed on an outer peripheral surface of a flat plate. The flat plate is inserted into the fore end of the steel pipe with the projections or ridges aligned with the slits or grooves, the projections abut against the end of the slit, and the insertion of further flat plates is restricted. With such a positioning mechanism, the positioning work of the flat plate can be simplified and the work efficiency of the joining work can be improved.

  According to a further preferred embodiment of the present invention, the positioning mechanism between the metal touch surfaces has a mechanical engagement element for positioning the relative position of the opposing metal touch surfaces, and the relative position between the metal touch surfaces is The mechanical engagement element is positioned by engaging the flat plate. The mechanical engagement element is formed of, for example, a rectangular cross-section key member that can be locked in a rectangular cross-section slot or slot formed in a flat plate.

  The key member performs substantially the same function as an erection piece mounted on the outer surface of the steel pipe, but unlike a conventional erection piece, it can be buried in the steel pipe joint. For this reason, by adopting such a key member, it is possible to omit the conventional work of cutting and removing the erection piece from the steel pipe and performing the grinder application processing of the piece engaging portion.

  The steel pipe joint structure of the present invention is not only a steel pipe joint structure that butt welds the joint ends of two steel pipes, but also butt welds with the joint ends of multiple (three or more) steel pipes as a single joint. It can be applied to steel pipe joint structure. Therefore, the present invention can be used extremely effectively as a steel pipe joint structure of a medium-scale or large-scale single-layer lattice structure.

  As an application of the present invention, a second flat plate or a flat plate assembly may be further interposed between the ends of the steel pipe in which the metal touch surface is formed by the flat plate. The metal touch at the end of the steel pipe joint is butt welded to the metal touch surface of the second flat plate or flat plate assembly, and the steel pipes are joined via the second flat plate or flat plate assembly. The second flat plate or the flat plate assembly constitutes a stress transmission means for the steel pipe. If desired, an erection piece having a simple structure for positioning the steel pipe and the second flat plate or flat plate assembly is used. The erection piece engages with, for example, the second flat plate or the flat plate assembly and also engages with the steel pipe and / or the flat plate at the end of the steel pipe to regulate the relative position between the second flat plate or the flat plate assembly and the steel pipe. .

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a side view partially showing a rigid connection truss structure provided with a steel pipe joint structure of the present invention.

  FIG. 1 shows an integral frame rigidly connected truss structure in which a steel pipe 1 having a true circular cross section is butt welded at a joint (joint) 2. In the truss structure shown in FIG. 1, steel pipes 1 having the same pipe diameter and the same thickness are rigidly connected as an upper chord material and a lower chord material. The central axes X and Y of the steel pipe 1 intersect at an angle α (0 ° <α <180 °). A steel flat plate 10 constituting a welding backing plate is internally provided at the end of each steel pipe 1. The key member 20 is engaged with the slots (long holes) 15 and 16 of the opposing flat plate 10, and the flat plate 10 is mutually locked by the key member 20. The joint end of the steel pipe 1 is integrally joined by a weld metal 30 of butt welding. The joint 2 of the upper steel pipe 1 shown as the upper chord and the joint 2 of the lower steel pipe 1 shown as the lower chord have substantially the same joint structure. A steel pipe 3 having a relatively small diameter is joined to the steel pipe 1 and the joint 2. After the butt welding of the steel pipe 2, the small diameter steel pipe 3 shown as an oblique member is fillet welded to the steel pipe 1 and the joint 2 according to a conventional welding method.

  FIG. 2 is a side view partially showing another rigid connection truss structure provided with the steel pipe joint structure of the present invention.

  The truss structure shown in FIG. 2 is also an integral frame rigid connection truss structure in which a steel pipe 1 having a true circular cross section is butt welded at a joint (joint) 2. The central axes X and Y of the steel pipe 1 intersect at an angle β (180 ° <β <360 °), and the steel flat plates 10 housed in the small ends of the steel pipes 1 are mutually connected by the key member 20. The joint end of the steel pipe 1 is rigidly connected by a weld metal 30 of butt welding. The upper and lower joint portions 2 have substantially the same joint structure, and a relatively small diameter steel pipe 3 is fillet welded to the steel pipe 1 and the joint portion 2.

  FIG. 3 is an enlarged longitudinal sectional view, an enlarged side view, and a schematic perspective view of the fore edge portion showing the joining portion 2 of the upper steel pipe 1 shown in FIG. 1 in a state before joining, and FIG. It is the expansion longitudinal cross-sectional view and the expansion side view which show the state which equipped the elliptical flat plate. 1 and 2 also has a joint structure that is substantially the same as the joint structure shown in FIGS. 3 and 4, so that the present invention will be described below with reference to FIGS. The joint structure will be described.

The end of each steel pipe 1 is laser-cut in advance by a three-dimensional (3D) laser processing machine. The cut end face (small facet) at the end of the joint is machined into an inclined surface having inclination angles α ₁ and α ₂ with respect to the central axes X and Y. As shown in FIG. 3C, an elliptical facet is formed at the end of the joint, and the facet has a horizontal minor axis Z that intersects the central axes X and Y. The fore edge is tapered so as to ensure the groove angle α ₃ of the welding gap, and a pair of left and right slits (grooves) 4 are formed. The slit 4 is disposed on the minor axis Z of the facet. The slit 4 opens in the facet and extends in parallel with the central axes X and Y over a predetermined length.

The side surfaces 13 and 14 of the flat plate 10 have an elliptical contour that can be inscribed in the opening of the steel pipe 1. The flat plate 10 has a cylindrical shape having an elliptical cross section, and the angles θ ₁ and θ ₂ formed by the cylindrical buses M ₁ and M ₂ and the bottom surface or top surface (side surfaces 13 and 14) are inclined angles α ₁ , It is set to be alpha ₂ and the same angle. Accordingly, the buses M ₁ and M ₂ are oriented parallel to the central axes X and Y of the steel pipe 1 and the inner peripheral surface 5.

  On the outer peripheral surface 11 of the flat plate 10, a pair of left and right protrusions (holograms) 12 that can be inserted into or fitted into the slit 4 are integrally formed. When the projection 12 and the slit 4 are aligned and the flat plate 10 is inserted into the small edge portion of the steel pipe 1, the projection 12 abuts the end portion of the slit 4 and further insertion of the flat plate 10 is prevented. Accordingly, the protrusion 12 and the slit 4 constitute a positioning mechanism that mechanically restricts the insertion position and relative rotation of the flat plate 10 while determining the relative position of the flat plate 10 and the steel pipe 1 when the flat plate 10 is inserted into the small opening. To do.

As shown in FIG. 4, the protrusion 12 is fitted into the slit 4, the outer peripheral surface 11 of the flat plate 10 is inscribed in the inner peripheral surface 5 of the fore edge, and the side surface 14 of the flat plate 10 is a distance S ₁ from the fore edge surface. It stops at the protruding position. FIG. 4 shows a state where the flat plate 10 is inserted into the fore edge.

The side surface 14 of the flat plate 10 forms an elliptical metal touch surface at an angle α ₁ with respect to the central axes X and Y at the end of each steel pipe 1. Slots (long holes) 15 and 16 having a rectangular cross section into which the key member 20 can be inserted are drilled in the opposing flat plate 10. The locking portion 21 of the key member 20 is locked in the slot 15 formed in one flat plate 10, and the locking portion 22 of the key member 20 is locked in the slot 16 formed in the other flat plate 10. To do.

  FIG. 5 is an enlarged longitudinal sectional view and an enlarged side view of the steel pipe joint showing a state in which the flat plate 10 is in surface contact. FIG. 6A is an enlarged longitudinal sectional view of the key member 20 and the slots 15 and 16. FIG. 6B is a cross-sectional view taken along the line II of FIG.

  When the side surface 14 of the flat plate 10 is brought into surface contact, the locking portion 21 of the key member 20 is inserted into the slot 15, and the locking portion 22 of the key member 20 is inserted into the slot 16. The slot penetrating portions 23 and 24 of the key member 20 are accommodated in the slots 15 and 16, respectively. The locking portions 21 and 22 are locked to the side surface (back surface) 13 of the flat plate 10 in each steel pipe 1.

  The key member 20 is made of a steel member having a square cross section having substantially the same width as the width of the slots 15 and 16, and the step portion 25 formed between the slot penetrating portions 23 and 24 includes the locking portion 21, The relative positions of the flat plates 10 are regulated in cooperation with the plate 22. The flat plate 10 whose relative position is fixed by the key member 20 holds the side surfaces 14 in a surface contact state. Thus, the key member 20 and the slots 15 and 16 constitute a positioning mechanism that positions the relative positions of the opposing metal touch surfaces (side surfaces 14).

  Since the edge surface of the steel pipe 1 is pre-grooved by a three-dimensional (3D) laser processing machine, the metal touch surface (side surface 14) is positioned at a position protruding from the edge surface of the steel pipe 1. As shown in FIG. 5, a welding gap 40 having a groove angle γ is formed between the facets of the steel pipe 1. A protruding portion of the outer peripheral surface 11 is exposed at the root portion of the welding gap 40, and the exposed portion of the outer peripheral surface 11 constitutes a welding backing.

  FIG. 7 is an enlarged longitudinal sectional view and an enlarged side view of a steel pipe joint portion showing a state in which the joint end of the steel pipe 1 is butt welded.

  The joint end of the steel pipe 1 is butt welded by welding one side of the welding gap 40 from the outside, and the steel pipe 1 is rigidly connected by the weld metal 30. Appropriate surpluses are made if desired. The flat plate 10 and the key member 20 remain in the steel pipe 1 and are buried in the joint 2.

  Thus, according to the steel pipe joint structure and the steel pipe joining method of the above configuration, the protrusion 12 and the slit 4 are aligned, the flat plate 10 is inserted into the small edge portion of the steel pipe 1, and the key member 20 and the slots 15, 16 are used for metal By relatively positioning the touch surfaces (side surfaces 14), the metal touch surfaces of the steel pipes 1 facing each other can be brought into surface contact with each other, and at the same time, a welding gap 40 for butt welding can be formed. Therefore, the joint end of the inclined steel pipe 1 does not use a special and dedicated joint member such as a cast steel truss node, and does not depend on advanced steel pipe cutting skills and steel pipe welding skills of welding experts, Butt welding is relatively easy.

  FIG. 8 is a partial view of a single-layer lattice dome provided with the joint structure of the present invention, and FIG. 9 is a partially enlarged sectional view of the steel pipe joint shown in FIG.

  FIG. 8 shows a steel structure framework of a single-layer lattice structure in which a steel pipe 1 having a true circular cross section is rigidly contacted at a joint portion (joint portion) 2. This steel structure frame constitutes a dome-like roof of a large space such as a stadium. In the joint portion 2, a large number of steel pipes 1 (four steel pipes 1 in this example) having the same pipe diameter and the same thickness are joined via a cross-shaped flat plate assembly 50.

As shown in FIG. 9, the fore edge portion of the steel pipe 1 is laser-cut in advance by a three-dimensional laser processing machine, and the fore edge portion has a fore edge surface (cut surface) parallel to the vertical joining surfaces 51 a and 51 b of the flat plates 51 and 52. . The flat plates 51 and 52 constitute a second flat plate inserted between the ends of the plurality of steel pipes. A flat plate 60 is inserted into the fore edge. Flat 60 is configured to protrude from the small surface of the steel pipe 1 by welding gap width S _2, the vertical joint surfaces 51a, contacts 51b and the surface. The steel pipe 1 is butt-welded to the flat plate assembly 50 by welding one side from the outside a welding gap formed between the facet surface and the vertical joint surfaces 51a and 51b.

  10 and 11 are exploded perspective views showing the structure of the end of the steel pipe 1 and the flat plate assembly 50. FIG.

  A flat plate 60 having the same function as the above-described flat plate 10 is inserted into the end of the steel pipe 1, and the flat plate 60 is inscribed in the small opening of the steel pipe 1. The flat plate assembly 50 is an assembly in which flat plates 51 and 52 having a circular outline and the same plate thickness are assembled.

  The flat plate 51 is formed with a top-opening vertical slit 53, and the flat plate 52 is formed with a bottom-opening vertical slit 54. A vertical bracket 55 that can be connected to another structural member by bolting or the like projects from the upper portion of the flat plate 51. By assembling the flat plates 51 and 52 with the slits 53 and 54 aligned, the flat plates 51 and 52 are assembled at right angles, and the cross-shaped flat plate assembly 50 shown in FIG. 11 is assembled. If desired, the contact portions of the flat plates 51 and 52 are partially welded, and the flat plate assembly 50 is integrated.

  The flat plate assembly 50 is placed on a jig 90 shown in FIG. The jig 90 includes a rectangular substrate 91 that can be seated on a support surface such as a work floor, and a cylindrical support portion 92 that is erected vertically to the substrate 91. A plurality of recesses 93 that can receive the flat plates 51 and 52 of the flat plate assembly 50 are formed at predetermined positions on the upper edge of the support portion 92. The flat plate assembly 50 is fixed at a predetermined position of the jig 90 with the lower edge portion inserted into the recess 93.

As shown in FIG. 10, the flat plate 60 is divided into a pair of flat plate divided pieces 61 that can be inscribed in the small opening of the steel pipe 1, and a plurality of protrusions 62 are formed on the outer peripheral surface 66 of each flat plate divided piece 61. In addition, a recess 63 that can be engaged with the erection piece 70 (FIG. 11) is formed. A plurality of recesses 6 into which the protrusions 62 can be inserted are formed in the small edge portion of the steel pipe 1, and a recess 7 that can be engaged with the erection piece 70 is formed. As shown in FIG. 11, the flat plate division piece 61 is inserted into the small opening of the steel pipe 1, and the protrusion 62 is inserted into the recess 6. The protrusion 62 abuts against the inner wall of the recess 6, and the outer side surface (metal touch surface) of the flat plate split piece 61 is positioned at a position protruding from the small edge surface of the steel pipe 1 by the welding gap width S ₂ . The left and right flat plate division pieces 61 abut on the front end of the steel tube 1 to form a vertical ridge 65 at the front end of the front end. Thus, a metal touch surface that can be brought into surface contact with the vertical joining surfaces 51 a and 51 b (FIG. 9) of the flat plates 51 and 52 is formed at the end of the steel pipe 1.

  As shown in FIGS. 10 and 11, the flat plate 52 is formed with a pair of square cross-section slots 56 into which the erection piece 70 can be inserted, and the erection piece 71 is fitted on the upper edge of the flat plate 52. A possible pair of recesses 57 is formed. The flat plate 60 and the recesses 63 and 7 of the steel pipe 1 are aligned to form a recess 8 that can engage with the erection piece 70 at the lower end of the joint end. A locking hole or recess 9 capable of locking the erection piece 71 is formed on the upper surface of the small-mouth portion of the steel pipe 1.

  The erection piece 70 is inserted into the slot 56 of the flat plate assembly 50, and the end of the steel pipe 1 is pushed against the flat plate assembly 50 so that the recess 8 of the steel pipe 1 engages the erection piece 70, thereby the flat plate 60. The outer surface (metal touch surface) and the vertical joint surfaces 51a and 51b (metal touch surface) of the flat plate assembly 50 can be brought into surface contact. The erection piece 71 is fitted in the recess 57 of the flat plate assembly 50, and both ends of the erection piece 71 are locked to the locking holes or the concave portions 9 of the steel pipe 1, so that the position of the steel pipe 1 is set to the flat plate assembly 50. Can be fixed. Therefore, the flat plate assembly 50 not only functions as a stress transmission means of the steel pipe 1, but also functions as a jig for positioning and error correction during welding.

  FIG. 12 is a cross-sectional view and a plan view showing a method for joining the steel pipe 1.

  The flat plate assembly 50 forms four right-angle corners 55, and the end of the steel pipe 1 is inserted into each corner 55. The vertical joining surfaces 51 a and 51 b (metal touch surface) of the flat plates 51 and 52 are in surface contact with the outer surface 60 a (metal touch surface) of the flat plate 60. The erection piece 70 is assembled to the flat plate assembly 50, and both end portions of the erection piece 70 are inserted into the recesses 8 of the respective steel pipes 1. The erection piece 71 is fitted in the recess 57 of the flat plate assembly 50 and is locked in the locking hole or the recess 9 of the steel pipe 1.

  13 is a cross-sectional view and a plan view showing a state in which the steel pipe 1 is assembled to the flat plate assembly 50. FIG. 14 is a cross-sectional view and a plan view showing a state in which the steel pipe 1 is butt welded to the flat plate assembly 50. FIG.

As shown in FIG. 13, a welding gap 80 having a welding gap width S ₂ is formed between the flat plate assembly 50 and the small face of the steel pipe 1. The outer peripheral surface 66 of the flat plate 60 is exposed at the root portion of the welding gap 40, and the exposed portion of the outer peripheral surface 66 constitutes a welding backing.

  By welding the welding gap 80 on one side from the outside, the steel pipe 1 is butt-welded to the flat plate assembly 50 as shown in FIG. 14, and thus the steel pipe 1 is joined so as to be able to transmit stress via the flat plate assembly 50. Part 2 is formed. If desired, the weld metal 81 between the steel pipe 1 and the flat plate assembly 50 is appropriately overfilled. The flat plate 60 is buried in the joint 2 and the erection pieces 71 and 72 are welded to the steel pipe 1. If desired, the erection pieces 71 and 72 may be removed, and the recesses 8 and 9 remaining in the joint portion 2 may be appropriately finished.

  FIG. 15 is a cross-sectional view and a plan view showing a steel pipe joint structure according to a modification of the first embodiment.

FIG. 15 shows a configuration of a joint portion 2 in which four steel pipes 1 are joined using the joint structure of the first embodiment (FIGS. 1 to 7). The flat plate 60 described in the second embodiment is inserted into the end of each steel pipe 1. The flat plates 60 are in direct surface contact with each other, and a welding gap 80 having a welding gap width S ₁ × 2 is formed at the end of the steel pipe 1. The steel pipe 1 is joined by butt welding of the welding gap 80.

  FIG. 16 is a cross-sectional view and a plan view showing a steel pipe joint structure according to a modification of the second embodiment.

FIG. 16 shows a joint 2 configured to join three steel pipes 1. The steel pipe 1 struck perpendicularly to the flat plate assembly 50 has a small face perpendicular to the central axis of the steel pipe 1, and a true circular flat plate 60 ′ is inserted into the small edge of the steel pipe 1. A welding gap 80 having a welding gap width S ₂ is formed between the flat plate assembly 50 and the end of the steel pipe 1, and the steel pipe 1 is joined to the flat plate assembly 50 by butt welding of the welding gap 80.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the above-described embodiments, and various modifications or changes can be made within the scope of the present invention described in the claims. Needless to say, such variations and modifications are also included in the scope of the present invention.

  For example, in the above-described embodiment, the cylindrical flat plates 10 and 60 having a uniform elliptical cross section over the entire height are used. However, the portions of the flat plates 10 and 60 protruding from the small edge surface of the steel pipe 1 are tapered or the like. It is also possible to change the cross section by the above.

  The present invention is not limited to the number of steel pipes that can be joined to a single joint or the inclination angle between steel pipes, and steel pipes having any number and inclination angles can be joined according to the present invention.

  Furthermore, in the said Example, although demonstrated regarding the joining of the steel pipe of a perfect circular cross section, this invention is applicable to joining of the steel pipe of various cross-sectional shapes, such as an elliptical cross section and a polygonal cross section.

  The present invention is applied to a steel pipe joint structure and a steel pipe joining method in which a structural steel pipe of a steel structure is butt welded at an arbitrary angle. The steel pipe joint structure and steel pipe joining method of the present invention is a steel structure to which a joint structure for joining steel pipes at an arbitrary angle must be applied everywhere, for example, a medium-scale or large-scale single-layer lattice structure. Can be preferably used.

It is a side view which shows partially the rigid connection truss structure provided with the steel pipe joint structure which concerns on 1st Example of this invention. It is a side view which shows partially the other rigid connection truss structure provided with the steel pipe joint structure of this invention. FIG. 2 is an enlarged longitudinal sectional view, an enlarged side view, and a small-portion schematic perspective view showing a joined portion of the upper steel pipe shown in FIG. 1 in a state before joining. It is an enlarged vertical sectional view and an enlarged side view showing a state in which an elliptical flat plate is installed at the end of a steel pipe. It is the expansion longitudinal cross-sectional view and enlarged side view of the steel pipe joint part which the state which made the flat plate surface contact shows. It is an expanded vertical sectional view and II sectional view taken on the line of a key member and a slot. It is the expanded longitudinal cross-sectional view and enlarged side view of the steel pipe joint part which show the state which butt-welded the joint end of the steel pipe. It is a top view which shows partially the single layer lattice dome provided with the steel pipe joint structure which concerns on 2nd Example of this invention. It is a partial expanded sectional view of the joint part shown in FIG. It is a disassembled perspective view which shows the connection end of a steel pipe, and the structure of a flat plate assembly. It is a disassembled perspective view which shows the connection end of a steel pipe, and the structure of a flat plate assembly. It is the cross-sectional view and top view which show the joining method of a steel pipe. It is the cross-sectional view and top view which show the state which assembled | attached the steel pipe to the flat plate assembly. It is the cross-sectional view and top view which show the state which butt-welded the steel pipe to the flat plate assembly. It is the cross-sectional view and top view which show the steel pipe joint structure which concerns on the modification of 1st Example. It is the cross-sectional view and top view which show the steel pipe joint structure which concerns on the modification of 2nd Example.

Explanation of symbols

1: Steel pipe 2: Joint part 4: Slit (groove)
10: flat plate 11: outer peripheral surface 12: protrusion 13: side surface (back surface)
14: Side (metal touch surface)
15: Slot (long hole)
16: Slot (long hole)
20: Key member 30: Weld metal 40: Weld gap 50: Flat plate assembly 51, 52: Flat plate (second flat plate)
60: flat 71: erection piece 80: Welding gap M _{1, M 2:} bus theta _1, theta _2: angle alpha _1, alpha _2: inclination angle X, Y: the central axis S _1: distance (projection amount)
S ₂ : Weld gap width

Claims (8)

In the steel pipe joint structure for butt welding the joint ends of steel pipes whose axis is relatively inclined,
The fore end portion of the steel pipe constituting the end of the joint has a fore end surface having an inclination angle with respect to the central axis of the steel pipe, and the outer peripheral surface of the flat plate having a metal touch surface is partially in the opening of the end end portion. The outer peripheral surface of the flat plate has a contour in which a generatrix with respect to the metal touch surface is oriented substantially parallel to a central axis of the steel pipe and inscribed in the opening of the fore edge, the metal touch surface is A steel pipe joint structure characterized by being positioned at a position protruding from the small edge portion. In the steel pipe joint structure for butt welding the joint ends of steel pipes whose axis is relatively inclined,
The fore end portion of the steel pipe constituting the end of the joint has a fore end surface having an inclination angle with respect to the central axis of the steel pipe, and the outer peripheral surface of the flat plate having a metal touch surface is partially in the opening of the end end portion. Inserted into
The small edge portion and the flat plate have a positioning mechanism that restricts the relative position of the flat plate and the steel pipe when the flat plate is inserted into the opening of the small edge portion, and mechanically restricts the insertion position and relative rotation of the flat plate. Features a steel pipe joint structure. In the steel pipe joint structure for butt welding the joint ends of steel pipes whose axis is relatively inclined,
The fore end portion of the steel pipe constituting the end of the joint has a fore end surface having an inclination angle with respect to the central axis of the steel pipe, and the outer peripheral surface of the flat plate having a metal touch surface is partially in the opening of the end end portion. Inserted into
The said flat plate has a positioning mechanism for positioning the relative position of the said metal touch surfaces which oppose, The steel pipe joint structure characterized by the above-mentioned.   The second flat plate or the flat plate assembly is further inserted between the ends of a plurality of steel pipes each having a metal touch surface formed by the flat plate. Steel pipe joint structure. In the steel pipe joining method of butt welding the joint ends of steel pipes whose axis is relatively inclined,
Cutting the fore end surface forming an angle of inclination with respect to the central axis of the steel pipe to form the end part of the joint end,
The outer peripheral surface of a flat plate having a metal touch surface is partially inserted into the opening of the fore edge, the outer peripheral surface of the flat plate is inscribed in the opening of the fore edge, and the metal touch surface protrudes from the fore edge. To position,
The metal touch surface is brought into surface contact with the metal touch surface of a member to be butt welded, and a welding gap is formed by the protrusion of the metal touch surface, and a welding backing is rooted by the outer peripheral surface of the welding gap. The steel pipe joining method characterized by forming in. In the steel pipe joining method of butt welding the joint ends of steel pipes whose axis is relatively inclined,
Inserting a flat plate having a metal touch surface that is partially inserted into the opening of the fore end while cutting the fore end with an inclination angle with respect to the central axis of the steel pipe to form the end of the end of the end Forming a mechanical engagement element for regulating position and relative rotation in the flat plate and the fore edge,
When the flat plate is inserted into the opening of the small opening, the relative position of the flat plate and the steel pipe is determined by the mechanical engagement element, and the insertion position and the relative rotation of the flat plate are limited by the mechanical engagement element. The steel pipe joining method characterized by the above-mentioned. In the steel pipe joining method of butt welding the joint ends of steel pipes whose axis is relatively inclined,
Cutting the fore end surface forming an angle of inclination with respect to the central axis of the steel pipe to form the end part of the joint end,
A peripheral surface of a flat plate having a metal touch surface is partially inserted into the opening of the fore edge portion, and a mechanical engagement element for positioning a relative position between the opposed metal touch surfaces is engaged with the flat plate. By this, the steel pipe joining method characterized by positioning the relative position of metal touch surfaces. A second flat plate or a flat plate assembly is further inserted between the ends of a plurality of steel pipes having a metal touch surface formed by the flat plate, and the metal touch surface is butt welded to the second flat plate or the flat plate assembly; The steel pipe joining method according to any one of claims 5 to 7.

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