Beam end joint structure

Abstract

To provide a beam end joint structure where an H-shaped cross section beam is joined to a support member, in which, when a fillet uncut part is formed at a scallop, a weld zone of an external bevel is suitably formed.SOLUTION: A beam end joint structure comprises: a bevel formed at an end part in a material axis direction of a first flange in an H-shaped cross section beam and opened toward a side opposite to a web; a scrap formed at the first flange side of the end of the web in the material axis direction and separated from the web side face of the first flange by an un-cut part of a fillet; and a backing strip forming a bottom part of the bevel. A first member of the backing strip comprises: a first face; and a second face, where the first face is brought into contact with or close to the web side face of the first flange, and the part on the first face side of the second face is brought into contact with or close to the un-cut part. The second member comprises: a third face in which at least a part is brought into contact with the second face; and a fourth face located on a side opposite to the first face with the web in between and brought into contact with or close to the web side face of the first flange.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a beam end joint structure. [Background technology]

[0002] For example, at the end of an H-shaped beam that is joined to a column, a scallop is formed by cutting out a part of the web that contacts the flange. By forming the scallop, it is possible to prevent interference between the welded part formed on the flange at the end of the H-shaped beam and the web. However, during an earthquake, strain is concentrated in the scallop, which is the missing part of the cross section, causing cracks, and the flange can break as the cracks propagate.

[0003] To address this problem, for example, Patent Document 1 describes a technique for reinforcing the portion of an H-section beam where a 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 for leaving a part of the fillet between the flange and the web uncut when forming the scallop, and forming the opening edge of the scallop on the flange side in a straight line spaced apart from the inner surface of the flange. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-7194 A [Patent Document 2] JP 2015-224427 A [Patent Document 3] JP 2020-133218 A Summary of the Invention [Problem to be solved by the invention]

[0005] According to the technology of the above-mentioned Patent Document 3, it is possible to suppress the concentration of strain and fracture at the bottom of the scallop that contacts the flange, and among them, the scallop having a fillet remaining part, which is listed as one of the embodiments, is expected to suppress fracture even more. However, Patent Document 3 describes the case where the groove formed at the flange end of the H-shaped cross section beam opens to the web side, so-called an inner groove. For example, in the case of on-site welding, the lower flange side is an inner groove, but the upper flange side is a so-called outer groove, in which the groove formed at the flange end opens to the opposite side from the web. Also, for example, in the case of factory welding, there are cases where the outer groove is formed regardless of the top and bottom of the flange. In the case of an outer groove, the backing metal and the fillet remaining part, which is one form of Patent Document 3, interfere with each other at the bottom of the groove, so the configuration of the fillet remaining part described in Patent Document 3 cannot be adopted using a backing metal composed of a normal one.

[0006] Therefore, the present invention aims to provide a beam end joint structure that can properly form an outer groove weld even when a fillet remaining portion is formed in the scallop, in a beam end joint structure that joins an H-shaped cross-section beam to a support member. [Means for solving the problem]

[0007] [1] A beam end joining structure for joining an H-shaped section beam having a first flange, a second flange and a web to a support member facing an end of the H-shaped section beam in a material axis direction, the beam end joining structure comprising: a groove formed at the end of the first flange in the material axis direction and opening toward the opposite side to the web; a scallop formed on the first flange side of the end of the web in the material axis direction and separated from the web side surface of the first flange by a fillet uncut portion between the first flange and the web; and a backing metal forming the bottom of the groove, the backing metal being formed on the same side as the first surface and adjacent to the longitudinal end of the first surface. a first member including a third surface having at least a portion in contact with the second surface and a fourth surface formed on the opposite side of the third surface, the fourth surface being brought into contact with or into contact with the web side surface of the first flange on the opposite side of the web from the first surface, and a weld formed by filling or stacking weld metal in the groove. [2] The beam end joint structure described in [1], wherein the first member further includes a connection surface that forms a sloped surface or curved surface between the first surface and the second surface corresponding to the shape of the fillet. [3] A beam end joint structure as described in [1], wherein one end face in the longitudinal direction of the second member forms a sloped or curved surface corresponding to the shape of the fillet. [4] The beam end joint structure described in [1], wherein the first member further includes a side wall portion formed at one end of the second surface in the width direction. [5] The beam end joint structure described in [1], wherein the first member further includes an end wall portion formed at the end portion opposite the first surface in the longitudinal direction of the second surface. [6] The first member further includes a through hole penetrating from a surface opposite to the second surface to the second surface, and the second member further includes a bolt hole formed in the third surface at a position corresponding to the through hole when the third surface is brought into contact with the second surface. The beam end joint structure described in [1]. [7] The beam end joint structure described in [6], wherein the through hole is a long hole extending in the longitudinal direction of the first member. Effect of the Invention

[0008] In the above configuration, the backing metal is divided into a first member and a second member, and the first surface formed on the first member and the fourth surface formed on the second member are brought into contact with or close to the web side surface of the flange, respectively, and the second surface formed stepwise downward from these surfaces is brought into contact with or close to the fillet remaining portion. In this way, interference between the backing metal and the fillet remaining portion can be avoided, thereby allowing the outer groove weld to be properly formed. [Brief description of the drawings]

[0009] [Figure 1] 1A to 1C are diagrams illustrating an example of a beam end joint structure according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 11 is a cross-sectional view showing a modified example of the backing metal. [Figure 4] FIG. 2 is a perspective view of the backing plate shown in FIG. 1. [Diagram 5] 5 is a diagram for explaining the effect of preventing welding defects in the example of FIG. 4. FIG. [Figure 6] 5 is a diagram showing a case where the side wall portion does not need to be formed in the example of FIG. 4. FIG. [Figure 7] FIG. 13 is a perspective view showing a modified example of the backing metal. [Figure 8] 13A-13C show examples of configurations for connecting two parts of a backing metal. [Figure 9] 13A-13C show examples of configurations for connecting two parts of a backing metal. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0011] FIG. 1 is a diagram showing an example of a beam-end joint structure according to an embodiment of the present invention. The beam-end joint structure 1 joins an H-shaped section beam 2 to a support member facing the end in the material axis direction. In the illustrated example, the support member includes a column 3 made of a square steel pipe or the like and diaphragms 31 and 32. The diaphragms 31 and 32 are inserted in the middle of the column 3 and welded to the column 3. The ends in the material axis direction of the upper flange 21 and the lower flange 22 of the H-shaped section beam 2 are joined to the diaphragms 31 and 32 by welds 41 and 42, respectively. Meanwhile, the end in the material axis direction of the web 23 is welded to the side surface 33 of the column 3 by a weld 43. The splice plate 34 is used to position the H-shaped section beam during construction and as a backing metal for the weld 43. Alternatively, the end of the web 23 in the material axis direction and the side surface 33 of the column 3 may not be welded, but the column 3 and the splice plate 34 may be welded together, and the H-shaped cross section beam and the column 3 may be joined by bolts via the splice plate 34. In another example, the diaphragm may be an internal diaphragm structure in which the diaphragm is attached to the inside of the column 3, and both the upper flange 21 and the lower flange 22 may be joined to the side surface 33 of the column 3 via welds.

[0012] At the ends of the upper flange 21 and the lower flange 22 of the H-shaped cross section beam 2 in the material axis direction, grooves 211, 221 are formed for filling or stacking the weld metal of the welds 41, 42. Backing metals 51, 52 are arranged at the bottoms of the welds 41, 42. For example, when the welds 41, 42 are constructed at a construction site, the groove 211 on the upper flange 21 side is an outer groove opened toward the opposite side to the web 23, and the groove 221 on the lower flange 22 side is an inner groove opened toward the web 23 side. Since various already known groove shapes and welding methods can be applied to the welds of the inner groove, detailed explanations of the welds 42 and the backing metal 52 are omitted. For example, when the welds 41, 42 are constructed at a factory, the lower flange 22 side is also an outer groove and is constructed in the same manner as the weld 41 on the upper flange 21 side described below.

[0013] Scallops 6, 7 are formed on the upper flange 21 side and the lower flange 22 side of the end of the web 23 in the material axis direction to avoid interference with the welded parts 41, 42. The scallops 6, 7 are separated from the web 23 side surfaces of the upper flange 21 and the lower flange 22 by fillet uncut parts 61, 71. The fillet uncut parts 61, 71 are parts of the fillets 24, 25 (welded parts joining the flange and web in the case of a welded assembled H-shaped cross section beam, and joint parts between the integrally molded flange and web in the case of a rolled H-shaped steel) between the upper flange 21 and the lower flange 22 and the web 23 that are not cut when the scallops 6, 7 are machined by cutting. The fillet uncut parts are formed to relieve the concentration of strain at the bottom of the circular arc part on the flange side of the scallop during, for example, an earthquake. In addition, when the flange of a welded H-section beam is bent toward the web, a fillet may be left uncut so that the flange surface is not cut off during scalloping. Note that the shapes of the scallops 6 and 7 shown in the figure are only examples, and various known scallop shapes can be used.

[0014] 2 is a cross-sectional view taken along line II-II in FIG. 1. As shown in the figure, the backing metal 51 is divided into a first member 51A and a second member 51B, which are arranged at the ends of the H-shaped cross-section beam 2 in the material axis direction as a whole to form the bottom of the groove 211. The first member 51A of the backing metal 51 includes a first surface 511 that is in contact with or close to the lower surface of the upper flange 21, i.e., the surface on the web 23 side, and a second surface 512 that is adjacent to the longitudinal end of the first surface 511 and is stepped down from the first surface 511. Here, it is desirable that the lower surface of the upper flange 21 and the first surface 511 (fourth surface 514) and the lower surface of the fillet remaining portion 61 and the second surface 512 are in contact without any gaps, i.e., in contact, in order to prevent the intrusion of moisture and the generation of rust, but they do not necessarily have to be in contact and may be in close proximity. The second surface 512 is brought into contact with the second member 51B as described below, but the portion of the second surface 512 on the first surface 511 side that is not in contact with the second member 51B is brought into contact with or close to the above-mentioned fillet uncut portion 61. In order to ensure assembly accuracy, it is desirable that the close distance between the above-mentioned surfaces when they do not come into contact is 3 mm or less. Since the surface of the fillet 24 between the fillet uncut portion 61 and the lower surface of the upper flange 21 is a sloped surface or curved surface as shown in the example, it is preferable to form a sloped surface or curved surface corresponding to the shape of the fillet 24 in the connection portion 515 between the first surface 511 and the second surface 512 facing the fillet 24, thereby reducing the gap between the backing metal 51 and the fillet 24.

[0015] On the other hand, the second member 51B of the backing metal 51 includes a third surface 513 that is brought into contact with the second surface 512 of the first member 51A described above, and a fourth surface 514 formed on the opposite side to the third surface 513, and the fourth surface 514 is brought into contact with or close to the lower surface of the upper flange 21. As shown in FIG. 2, the position at which the fourth surface 514 is brought into contact with or close to the lower surface of the upper flange 21 is the opposite side across the web 23 from the position at which the first surface 511 of the first member 51A is brought into contact with or close to the lower surface of the upper flange 21. One end surface 516 in the longitudinal direction of the second member 51B faces the fillet 24 in the same manner as the connection portion 515 of the first member 51A, so that it is preferable to form a sloped surface or a curved surface corresponding to the shape of the fillet 24 on the end surface 516 as well, thereby reducing the gap between the backing metal 51 and the fillet 24. With regard to connecting portion 515 and end surface 516, an example in which an inclined surface is formed is shown in FIG. 2, and a modified example in which a curved surface is formed is shown in FIG.

[0016] In the above example, the scallop 6 on the upper flange 21 side is formed with the fillet remaining portion 61, and the groove 211 is an outer groove. In such a case, for example, a normal backing metal that covers the entire width of the upper flange 21 with one piece will interfere with the fillet remaining portion 61 and will not be able to close the bottom of the groove 211. In this embodiment, the backing metal 51 is divided into a first member 51A and a second member 51B, and the first surface 511 formed on the first member 51A and the fourth surface 514 formed on the second member 51B are brought into contact with or close to the lower surface of the upper flange 21, respectively, and the second surface 512 formed stepwise downward from these surfaces is brought into contact with or close to the fillet remaining portion 61, thereby making it possible to close the entire bottom of the groove 211. By forming the first surface 511 and the second surface 512 on the same first member 51A and configuring the backing metal 51 as a whole from two members, it is possible to minimize an increase in the number of parts. Also, by adopting a structure in which the second member 51B is placed on the second surface 512 of the first member 51A, it is possible to prevent the second member 51B from falling off during construction, thereby improving workability.

[0017] In order to reduce the gap at the bottom of the groove 211, it is desirable that the height h1 of the step between the first surface 511 and the second surface 512 of the first member 51A is approximately equal to the thickness t of the second member 51B and approximately equal to the height h2 of the fillet uncut portion 61. As a non-limiting example, the fillet uncut portion 61 is formed so that the height h2 is about 2 mm to 6 mm, so it is desirable to prepare a first member 51A with a step height h1 corresponding to this and a second member 51B with a thickness t.

[0018] FIG. 4 is a perspective view of the backing metal shown in FIG. 1. As described above, the backing metal 51 includes a first member 51A and a second member 51B, and the second member 51B is placed on the second surface 512 of the first member 51A. Furthermore, as shown in the figure, the first member 51A has a side wall portion 517 formed at one end in the width direction of the second surface 512. By forming the side wall portion 517, as shown in FIG. 5, the gap generated between the second surface 512 and the end surface of the diaphragm 31 at the portion where the second surface 512 abuts or is brought close to the fillet remaining portion 61 can be closed, and welding failure can be prevented. Note that, as shown in FIG. 6, there are cases where the plate thickness of the diaphragm 31 is large, and cases where no gap is generated between the second surface 512 and the surface of the support member as in the case of the inner diaphragm described above, and in such cases, the side wall portion 517 does not need to be formed. Furthermore, by forming the side wall portion 517, the position of the second member 51B can be easily stabilized even when the second member 51B contacts only a part of the second surface 512 of the first member 51A as in the example of Fig. 3. Therefore, the side wall portion 517 may be formed regardless of the presence or absence of a gap between the diaphragm 31 as described above.

[0019] FIG. 7 is a perspective view showing a modified example of the backing metal shown in FIG. 4. In the illustrated example, the first member 51A is formed with an end wall 518 in addition to the side wall 517. The end wall 518 is formed at the end of the second surface 512 on the opposite side to the first surface 511 in the longitudinal direction. By forming the end wall 518, it is possible to more reliably prevent the second member 51B from falling off during construction. As described above, there are cases where the side wall 517 does not need to be formed, and in that case, only the end wall 518 may be formed. When the end wall 518 is formed as in the example of FIG. 7, the length of the second surface 512 of the first member 51A is longer than the length of the second member 51B, and the entire third surface 513 is in contact with the second surface 512 of the first member 51A. In other cases, the length of the second surface may be shorter than the length of the second member 51B, and only a portion of the third surface 513 may be in contact with the second surface 512.

[0020] The welded portion 41 using the backing metal 51 as described above is constructed, for example, in the following procedure. After the H-shaped cross-section beam 2 is erected in a predetermined position relative to the column 3, the backing metal 51 is placed on the bottom of the groove 211. At this time, the backing metal 51 can be transported and placed in a predetermined position with the second member 51B placed on the second surface 512 of the first member 51A, as in the example shown in FIG. 6 or FIG. 7. When placing the backing metal 51, since the first member 51A and the second member 51B can be moved independently, the backing metal 51 can be brought into close contact with the bottom of the groove 211 in accordance with, for example, the thickness of the web 23 or the shape of the fillet 24. Specifically, for example, the first member 51A is first positioned so that the first surface 511 is in close contact with the lower surface of the upper flange 21, the second surface 512 is in close contact with the fillet uncut portion 61, and the connection portion 515 is in close contact with the fillet 24, and then assembled and welded. Next, on the opposite side of the web 23, the second member 51B inserted in the gap between the upper flange 21 and the second surface 512 of the first member 51A is slid in the longitudinal direction of the backing metal 51, and positioned so that the fourth surface 514 is in close contact with the lower surface of the upper flange 21 and the end surface 516 is in close contact with the fillet 24. Since the second member 51B is inserted in the gap, assembly welding is optional. In addition to this method, there is also a method in which the second member 51B is first positioned so that it is in close contact with the lower surface of the upper flange 21 and then assembled and welded, and then, on the opposite side of the web 23, the first surface 511 of the first member 51A is positioned so that it is in close contact with the upper flange 21 and the connection portion 515 is in close contact with the fillet 24 and then assembled and welded. As a result, the bottom of the groove 211 is formed by the first surface 511, the second surface 512, and the fourth surface 514 of the backing metal 51, and the groove 211 can be filled or layered with weld metal to form the welded portion 41.

[0021] 8 and 9 are diagrams showing an example of a configuration for connecting two parts of a backing metal. In the example of FIG. 8, a through hole 531 is formed in the first member 51A, a bolt hole 532 is formed in the second member 51B, and a bolt 533 inserted into the through hole 531 from the back side of the first member 51A is screwed into the bolt hole 532. This connects the first member 51A and the second member 51B, so that the second member 51B does not fall off the first member 51A during transportation, and for example, the backing metal 51 can be transported by holding only the first member 51A. The backing metal 51 is placed at the installation position, and when the positioning and assembly welding of the first member 51A are completed as described above, the bolt 533 is loosened and removed from the bolt hole 532 and the through hole 531, so that the second member 51B can be freely slid and positioned relative to the first member 51A.

[0022] 9, the through hole 531A formed in the first member 51A is an elongated hole extending in the longitudinal direction of the first member 51A. As a result, similarly to the example of FIG. 8, the first member 51A and the second member 51B can be connected by screwing the bolt 533 inserted through the through hole 531A into the bolt hole 532, and the second member 51B can be slid in the longitudinal direction to be positioned without removing the bolt 533.

[0023] In the above, the case where groove 211 for forming weld 41 on the upper flange 21 side is an outer groove has been described, but as already mentioned, for example, when a beam-end joint structure is constructed in a factory, groove 221 on the lower flange 22 side is also an outer groove and is constructed in the same manner as weld 41 on the upper flange 21 side. In this case, backing metal 52 forming the bottom of groove 221 is also arranged on the web 23 side of lower flange 22, opposite to the example in Fig. 1, and may be composed of a first member and a second member like backing metal 51. [Explanation of symbols]

[0024] 1...beam end joint structure, 2...H-section beam, 21...upper flange, 22...lower flange, 23...web, 24,25...fillet, 211,221...groove, 3...column, 31...diaphragm, 32...diaphragm, 33...side, 34...splice plate, 41,42,43...weld, 51,52...backing plate, 51A...first member, 51B...second member, 511...first surface, 512...second surface, 513...third surface, 514...fourth surface, 515...connection portion, 516...end surface, 517...side wall portion, 518...end wall portion, 531,531A...through hole, 532...bolt hole, 533...bolt, 6,7...scallop, 61,71...fillet remaining portion.

Claims

1. A beam end joint structure for joining an H-shaped cross-section beam having a first flange, a second flange, and a web to a support member facing an end of the H-shaped cross-section beam in a material axis direction, A groove is formed at an end of the first flange in the material axis direction and opens toward an opposite side to the web; a scallop formed on the first flange side of an end of the web in the material axis direction and separated from the web side surface of the first flange by an uncut portion of a fillet between the first flange and the web; A backing metal forming a bottom of the groove, a first member including a first surface and a second surface formed on the same side as the first surface, adjacent to a longitudinal end of the first surface, and stepping down from the first surface, the first surface being brought into contact with or close to the web side surface of the first flange, and a portion of the second surface on the first surface side being brought into contact with or close to the uncut portion; a second member including a third surface at least a portion of which is brought into contact with the second surface, and a fourth surface formed on the opposite side to the third surface, the fourth surface being brought into contact with or close to the web side surface of the first flange on the opposite side to the first surface across the web; A backing metal including: a weld formed by filling or laminating a weld metal in the groove; A beam end joint structure comprising:

2. The beam end joint structure according to claim 1 , wherein the first member further includes a connection surface that forms a sloped or curved surface corresponding to a shape of the fillet between the first surface and the second surface.

3. The beam end joint structure according to claim 1 , wherein one end face in the longitudinal direction of the second member forms a sloped surface or a curved surface corresponding to the shape of the fillet.

4. The beam-end joint structure according to claim 1 , wherein the first member further includes a side wall portion formed at one end in a width direction of the second surface.

5. The beam end joint structure according to claim 1 , wherein the first member further includes an end wall portion formed at an end portion of the second surface opposite the first surface in the longitudinal direction.

6. The first member further includes a through hole penetrating from a surface opposite to the second surface to the second surface, The beam end joint structure described in claim 1, wherein the second member further includes a bolt hole formed in the third surface at a position corresponding to the through hole when the third surface is brought into contact with the second surface.

7. The beam end joint structure according to claim 6 , wherein the through hole is a long hole extending in the longitudinal direction of the first member.

Images