JP7598026B2 - Beam joint structure and method for manufacturing the beam joint structure - Google Patents

Description

The present invention relates to a beam joint structure and a method for manufacturing a beam joint structure.

For example, at the end of an H-shaped beam that is joined to a column, a scallop is formed by cutting out a portion of the web that contacts the flange. By forming the scallop, it is possible to prevent interference between the weld formed on the flange at the end of the H-shaped beam and the web. However, cracks can occur due to strain concentration at the scallop, which is a cross-sectional defect, and the flange can break as the cracks propagate.

To address this issue, for example, Patent Document 1 describes a technique for reinforcing the portion of the H-section beam where the scallop is formed by joining a tapered plate to the outside of the flange. Patent Document 2 describes a technique for reinforcing the scallop by filling it with welding after welding the flange. Patent Document 3 describes a technique in which the opening edge on the flange side of the scallop is formed in a straight line spaced away from the inner surface of the flange, and the groove surface for welding formed on the flange extends beyond the inner surface of the flange to the web side and intersects with the opening edge of the scallop.

JP 2013-7194 A JP 2015-224427 A JP 2020-133218 A

The technology of Patent Document 3 mentioned above makes it possible to prevent strain concentration and fracture at the bottom of the scallop that contacts the flange. However, Patent Document 3 only describes the case where the groove formed at the flange end of the H-shaped cross section beam opens toward the web, a so-called internal groove. For example, in the case of on-site welding, the lower flange side is an internal groove, but on the upper flange side, the groove formed at the flange end opens toward the opposite side from the web, a so-called external groove, so the configuration of the lower flange side described in Patent Document 3 cannot be adopted. Also, for example, in the case of factory welding, an external groove may be formed regardless of the top or bottom of the flange.

The present invention aims to provide a beam joint structure and a manufacturing method for a beam joint structure that can prevent strain concentration and breakage when a groove that opens toward the opposite side of the web is formed at the end of the flange in a beam joint structure formed between an H-shaped cross-section beam and a support member.

[1] A beam joint structure formed between an H-shaped cross-section beam and a support member, wherein a groove is formed at an end of at least one flange of the H-shaped cross-section beam facing the support member in the material axis direction, the end of the web in the material axis direction is opened toward the opposite side to the web of the H-shaped cross-section beam, a scallop is formed at the end of the web in the material axis direction, the opening edge of the scallop is formed away from the inner surface of at least one flange, the beam joint structure includes first and second side end faces and first and second plate surfaces, a notch is formed in the first plate surface that does not penetrate to the second plate surface and is open only to the second side end face side, and a groove is formed between the second side end face and the first plate surface. A backing metal is placed such that the length of the notch in the intersecting direction is greater than or equal to the width of the intersection between the at least one flange and the web, the first side end face is abutted against a support member, and further, the first plate face is abutted against at least one of the inner surface of the at least one flange and the bottom surface of the notch and the opening edge of the scallop, and an area is formed at the bottom of the groove which is surrounded by the bottom surface of the notch, the convex portion between the notch and the first side end face, and the end face of the web continuing to the opening edge of the scallop, the area is filled with weld metal, and the groove is further filled with weld metal.
[2] A beam joining method for joining an H-shaped cross-section beam to a support member, the beam having an H-shaped cross-section beam including a first and second side end faces and a first and second plate surface, a notch formed in the first plate surface that does not penetrate to the second plate surface and is open only to the second side end face side, and a length of the notch in the direction of the intersection between the second side end face and the first plate surface is equal to or larger than the length of the first plate surface. A manufacturing method for a beam joint structure includes the steps of: placing a backing metal that is equal to or greater than the width of the intersection between the at least one flange and the web, abutting the first side end face against a support member, and further abutting the first plate surface against the inner surface of the at least one flange, or the bottom surface of the notch against the opening edge of the scallop; filling or stacking weld metal in a groove-shaped area formed at the bottom of the groove and surrounded by the bottom surface, the convex portion between the notch and the first side end face, and the end surface of the web continuing to the opening edge of the scallop; and filling or stacking weld metal in the groove.

According to the above configuration, the groove-shaped area is filled by filling or layering the weld metal, and the opening edge of the scallop can be integrated with the backing metal or the weld metal of the groove, so that no geometric discontinuity is formed, and the concentration of strain that occurs at the geometric discontinuity and the resulting breakage of the flange can be prevented.

1 is a cross-sectional view showing an entire beam joint structure according to one embodiment of the present invention; FIG. 4 is a cross-sectional view showing the structure of a welded portion according to a reference example. 1 is a perspective view of a backing metal used in a beam joint structure according to one embodiment of the present invention; FIG. 4 is a cross-sectional view showing the structure of a welded portion using the backing metal shown in FIG. 3, and the cross-sectional view of the backing metal is taken along line IV-IV in FIG. FIG. 13 is a diagram for explaining an embodiment of the present invention in which an analysis was performed. FIG. 13 is a diagram for explaining a comparative example in which an analysis was performed. FIG. 13 is a diagram for explaining a comparative example in which an analysis was performed. FIG. 13 is a diagram for explaining a comparative example in which an analysis was performed. FIG. 5B is a diagram showing distortions calculated by FEM analysis in the embodiment shown in FIG. 5A. FIG. 5C is a diagram showing strain calculated by FEM analysis in the comparative example shown in FIG. 5B. FIG. 5D is a diagram showing strain calculated by FEM analysis in the comparative example shown in FIG. 5C. FIG. 5E is a diagram showing strain calculated by FEM analysis in the comparative example shown in FIG. 5D.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. Note that in this specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals to avoid redundant description.

Figure 1 is a cross-sectional view showing the entire beam joint structure according to one embodiment of the present invention. In this embodiment, the beam joint structure between the H-shaped section beam 1 and the support member 2 is formed by on-site welding. The H-shaped section beam 1 includes an upper flange 11, a lower flange 12, and a web 13. The support member 2 includes, for example, a steel pipe column and a diaphragm attached thereto, but is not limited to this example. The upper flange 11 and the lower flange 12 of the H-shaped section beam 1 are each joined by welding to the support member 2, specifically, for example, the end face of the diaphragm.

As described above, the beam joint structure according to this embodiment is formed by on-site welding, so the upper flange 11 side has an outer groove, and the lower flange 12 side has an inner groove. Specifically, as shown in the figure, a groove 111 is formed at the end of the upper flange 11 facing the support member 2 in the material axis direction, which opens toward the opposite side of the web 13, and a groove 121 is formed at the end of the lower flange 12 facing the support member 2 in the material axis direction, which opens toward the web 13 side. Note that this example is not limiting. As already mentioned, for example, in the case of factory welding, the groove is an outer groove regardless of the top and bottom of the flange. Therefore, the problems that may occur in the case of an outer groove as described below, and the solution method according to this embodiment are applicable to at least one flange (whether it is the upper flange or the lower flange, or whether it is one or both) of the H-shaped cross section beam joined to the support member.

At the ends of the web 13 in the material axis direction, scallops 131 and 132 are formed, which are notches for avoiding interference between the welds formed on the upper flange 11 and the lower flange 12 and the web 13. In the illustrated example, the scallops 131 and 132 are composite circular shapes including a small-radius arc portion located on the center side of the web 13 and a large-radius arc portion located on the upper flange 11 or lower flange 12 side, but this example is not limited to this and various scallop shapes can be applied. In the scallops 131 and 132, the opening edges 131A and 132A on the upper flange 11 or lower flange 12 side are formed away from the inner surface 11S of the upper flange 11 and the inner surface 12S of the lower flange 12, respectively. Here, the inner surface 11S of the upper flange 11 and the inner surface 12S of the lower flange 12 refer to the surfaces of the respective flanges on the web 13 side. Due to the shape of the scallops 131 and 132, the opening edges 131A and 132A do not intersect with the flanges, and therefore it is possible to avoid concentration of strain and breakage that may occur at the intersection of the opening edges and the flanges. The distance between the opening edge of the scallop and the inner surface of the flange is not particularly limited as long as it is spaced apart, but it is preferable that the distance is 2 mm to 13 mm because it is necessary to avoid concentration of strain and breakage by intersecting the toe of the welded part of the flange and the web in a welded assembled H-shaped cross-section beam, and the toe of the fillet in a rolled H-shaped steel and the arc of the scallop, and to avoid cutting the inner surface of the flange during cutting of the scallop. The height of the scallop opening may be a height that allows welding work to be performed on the welded part, and if the opening is too wide, it is not preferable from the viewpoint of strength. The height of the scallop opening is substantially preferably 25 mm to 40 mm.

In the illustrated example, on the lower flange 12 side, the inclined surface 121S of the groove 121 extends beyond the inner surface 12S of the lower flange 12 to the opening edge 132A of the scallop 132. During welding, a backing metal (not shown) is abutted against the outer surface of the lower flange 12, i.e., the surface opposite the web 13, to fill or stack the weld metal in the groove 121, and then the opening edge 132A of the scallop 132 is smoothly connected to the support member 2 side by decorative welding. This prevents a shape discontinuity from occurring at the end of the web 13 in the material axis direction, making it easier to transmit the stress of the H-shaped cross section beam 1 to the support member 2. The configuration of such a weld part on the lower flange 12 side has already been described, for example, in JP 2020-133218 A, but is not limited to this example and various types of groove shapes and welding methods for the lower flange can be applied.

On the other hand, on the upper flange 11 side, the inner surface 11S of the upper flange 11 hits the bottom of the groove 111, which is the opposite to the lower flange 12 side, so the configuration of the welded part is not the same as that of the lower flange 12 side. In addition, the opening edge 131A of the scallop 131 is a part of the web 13 that protrudes from the inner surface 11S of the upper flange 11 and remains, so it interferes with the backing metal (not shown) that is abutted against the inner surface 11S of the upper flange 11 along the bottom of the groove 111. For example, if the backing metal is divided and placed on both sides of the web 13, it is possible to fill or stack the weld metal 41 in the groove 111 and weld it as shown in Figure 2, but a geometric discontinuity 13X occurs at the end of the web 13 in the material axis direction following the opening edge 131A of the scallop 131. At such a geometric discontinuity 13X, there is a possibility that strain concentration or breakage may occur.

Therefore, in this embodiment, the above problem is solved by using a backing metal of the shape described below on the upper flange 11 side of the beam joint structure.

Figure 3 is a perspective view of a backing metal used in a beam joint structure according to one embodiment of the present invention. Figure 4 is a cross-sectional view showing the structure of a welded portion using the backing metal shown in Figure 3, and the backing metal is a cross-sectional view taken along line IV-IV in Figure 3. As shown in Figure 3, the backing metal 3 is a plate-shaped member having plate surfaces 31, 32, side end surfaces 33, 34, and end surfaces 35, 36 as a whole. One side end surface 33 is abutted against the support member 2 in the beam joint structure as shown in Figure 4. In addition, a notch 311 is formed in the plate surface 31, which is open to the side end surface 34 side opposite to the side end surface 33. Since the notch 311 does not penetrate to the plate surface 32 on the opposite side, a bottom surface 312 of the notch 311 that constitutes a surface one step lower than the plate surface 31 is formed. The bottom surface 312 abuts against the opening edge 131A of the scallop 131 in the beam joint structure, or the plate surface 31 abuts against the inner surface 11S of the upper flange 11 in a portion other than the notch 311 not shown in FIG. 4. At this time, the gap that occurs when one of the bottom surface 312 and the opening edge 131A of the scallop 131, or the plate surface 31 and the inner surface 11S of the upper flange 11 is not abutted is preferably 2 mm or less, more preferably 1 mm or less, and more preferably both are abutted. In this application, "abutting" means that at least a portion of the abutting parts or at least a portion of the abutting surfaces are in contact with each other. It is not necessary that they are in close contact with no gaps or that all of the abutting surfaces are in contact.

In the backing metal 3 as described above, the notch 311 is not open on the side end face 33 side, so a convex portion 313 is formed with respect to the bottom face 312 of the notch 311 between the side end face 33 that abuts against the support member 2 and the notch 311. By making the distance L ₁ from the notch 311 to the side end face 33, i.e., the length of the top of the convex portion 313, less than the distance L ₂ between the upper flange 11 at the bottom of the groove 111 and the support member 2, a groove-shaped region 111G is formed at the bottom of the groove 111 as shown in FIG. 4. The region 111G is surrounded by the bottom face 312 of the notch 311, the convex portion 313, and the end face 13E of the web 13 that continues to the opening edge 131A of the scallop 131.

The convex portion 313 does not necessarily have to be a trapezoidal portion as shown in the figure. For example, the notch 311 side of the convex portion 313 may be a surface inclined with respect to the bottom surface 312 instead of a surface perpendicular to the bottom surface 312. In this case, the convex portion 313 does not necessarily have to have a shape having a flat surface at the top as shown in Figures 3 and 4, and the cross section of the top may be a shape forming an acute angle. In this case, the distance L ₁ shown in Figure 4, i.e., the length of the top of the convex portion 313, becomes 0, and if there is even a small length L ₂ of the gap at the bottom of the groove 111, the region 111G is formed.

In the welded portion on the upper flange 11 side as described above, the weld metal 41 is first filled or layered to fill the region 111G, and then the weld metal 42 is filled or layered in the groove 111. By filling the region 111G with the weld metal 41, the opening edge 131A of the scallop 131 is integrated with the backing metal 3 and the weld metal 42 of the groove 111 via the weld metal 41. Therefore, in this embodiment, no geometric discontinuity is formed as described above with reference to FIG. 2, and it is possible to prevent the concentration of strain that occurs at the geometric discontinuity and the resulting breakage of the flange.

In order to form the above-mentioned welded portion, the length B (see FIG. 3) of the notch 311 in the direction of the intersection between the side end surface 34 and the plate surface 31 in the backing metal 3 is equal to or greater than the width of the intersection between the upper flange 11 and the web 13. Here, for example, when the H-shaped section beam 1 is a rolled H-shaped steel, the width of the intersection between the flange and the web corresponds to the dimension obtained by adding the width of the fillet portion formed during rolling to the plate thickness of the web. Also, when the H-shaped section beam 1 is a welded H-shaped section beam, the width of the intersection between the flange and the web corresponds to the dimension obtained by adding the plate thickness of the web to the leg length of the welded portion with the flange. Also, in the backing metal 3, the depth D ₁ (see FIG. 3) of the bottom surface 312 of the notch 311 with respect to the plate surface 31 is equal to the height D ₂ (see FIG. 4) of the opening edge 131A of the scallop 131 with respect to the inner surface 11S of the upper flange 11. Incidentally, there is no particular upper limit to the length B of the notch 311, but from the viewpoint of preventing weld burn-through from the notch during welding work, in the case of a rolled H-shaped steel beam, it is preferable that the width be equal to or less than the dimension obtained by adding the thickness of the web to the width of the fillet portion plus 10 mm, or in the case of a welded assembled H-shaped cross section beam, that the width be equal to or less than the dimension obtained by adding the thickness of the web to the leg length of the weld with the flange plus 10 mm.

The following describes the analysis results showing the effect of the beam joint structure according to the embodiment of the present invention. Figures 5A to 5D are diagrams for explaining the embodiment and comparative example of the present invention in which the analysis was performed. Figures 6A to 6D are diagrams showing the strain calculated by FEM analysis in the embodiment and comparative example shown in Figures 5A to 5D, respectively. Figures 5A and 6A show an embodiment of the present invention in which a backing metal having a notch is used to form a groove-like area at the bottom of the groove formed in the upper flange and fill it with weld metal. Figures 5B and 6B show a comparative example in which the opening edge of the scallop is cut vertically to widen the gap with the support member and a backing metal with a rectangular cross section is abutted against it. Figures 5C and 6C show a comparative example in which the opening edge of the scallop is cut into a tapered shape opening at an angle of 60° toward the web side and a backing metal with a trapezoidal cross section including an inclined surface at an angle of 60° is abutted against it. Figures 5D and 6D show a comparative example in which the opening edge of the scallop is machined into a concave curved surface and a backing metal with a cross-sectional shape that includes a corresponding convex curved surface is abutted against it.

As shown in FIG. 6A, in the beam joint structure according to the embodiment of the present invention, no concentration of strain occurs in the portion of the upper flange 11 or the web 13 that contacts the backing metal. In contrast, in the comparative example shown in FIG. 6B, the backing metal and the opening edge of the scallop are not integrated, so that concentration of strain occurs near the shape discontinuity point of the end of the web that contacts the backing metal. In the comparative example shown in FIG. 6C and FIG. 6D, tapering and curving are performed to reduce the shape discontinuity at the end of the web that contacts the backing metal, but still, concentration of strain occurs in the cut portion of the opening edge of the scallop that contacts the backing metal. From these analysis results, it can be seen that the configuration of the embodiment of the present invention, in which a groove-shaped area is formed at the bottom of the groove with the backing metal and this area is filled with weld metal to integrate the opening edge of the scallop with the backing metal or weld metal, is effective in preventing concentration of strain and the resulting breakage of the flange.

The above describes in detail preferred embodiments of the present invention with reference to the attached drawings, but the present invention is not limited to such examples. It is clear that a person with ordinary knowledge in the technical field to which the present invention pertains can conceive of various modified or revised examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

1...H-section beam, 11...upper flange, 11S...inner surface, 111...groove, 111G...area, 12...lower flange, 12S...inner surface, 121...groove, 121S...inclined surface, 13...web, 13E...end surface, 13X...geometric discontinuity, 131...scallop, 131A...opening edge, 132...scallop, 132A...opening edge, 2...support member, 3...backing metal, 31, 32...plate surface, 33, 34...side end surface, 35, 36...end surface, 41, 42...weld metal, 311...notch, 312...bottom surface, 313...convex portion.

Claims (2)

A beam joint structure formed between an H-shaped cross-section beam and a support member,
At least one flange of the H-shaped cross section beam facing the support member has an end portion in the material axis direction thereof formed with a groove that opens toward the opposite side of the web of the H-shaped cross section beam;
A scallop is formed at an end of the web in the material axis direction, and an opening edge of the scallop is formed away from an inner surface of the at least one flange,
a backing metal is disposed, the backing metal including first and second side end faces and first and second plate faces, a notch is formed in the first plate face that does not penetrate to the second plate face and is open only to the second side end face side, and a length of the notch in a direction of an intersection between the second side end face and the first plate face is equal to or greater than a width of an intersection between the at least one flange and the web;
the first side end surface is in contact with the support member,
Furthermore, at least one of the first plate surface and an inner surface of the at least one flange, or the bottom surface of the notch and an opening edge of the scallop, is in contact with each other,
A region surrounded by the bottom surface, a convex portion between the notch and the first side end surface, and an end surface of the web continuing to an opening edge of the scallop is formed at the bottom of the groove,
A beam joint structure in which the region is filled with weld metal and the groove is further filled with weld metal. A beam joining method for joining an H-shaped cross section beam to a support member, the method comprising forming a groove at an end of at least one flange facing a support member in a material axis direction, the end of the web in the material axis direction being formed with a scallop, and the opening edge of the scallop being spaced apart from the inner surface of the at least one flange, the method comprising the steps of:
a step of disposing a backing metal including first and second side end faces and first and second plate faces, a notch being formed in the first plate face that does not penetrate to the second plate face and is open only to the second side end face side, and a length of the notch in a direction of an intersection between the second side end face and the first plate face is equal to or greater than a width of an intersection between the at least one flange and the web, the step of abutting the first side end face against the support member,
a step of abutting the first plate surface against at least one of an inner surface of the at least one flange, or a bottom surface of the notch against an opening edge of the scallop;
a step of filling or stacking a weld metal in a groove-shaped region surrounded by the bottom surface, a protrusion between the notch and the first side end surface, and an end surface of the web continuing to an opening edge of the scallop, the groove-shaped region being formed at the bottom of the groove;
and filling or laminating a weld metal in the groove.

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