JP6703303B2 - Beam-column connection and beam-column joining method - Google Patents

Description

The present invention relates to a structure of a column-beam joint in which a flange of an H-section steel and a flange of a beam are welded and joined together through a groove, and a method of welding and joining these columns and beams through a groove. Regarding

BACKGROUND ART Conventionally, in a joint portion between an H-shaped steel column and a beam used in a steel frame structure, a joint portion in which a column flange and a beam flange are welded and joined is used.

FIG. 8: is a figure explaining the structure of the conventional beam-column joint part. In the column-beam joint portion 10, the flange 21 of the column 20 (hereinafter, referred to as the column flange 21) and the flange 31 of the beam 30 (hereinafter, referred to as the beam flange 31) are completely formed through the rectangular groove 40. Joined by penetration welding. That is, the backing metal 50 is provided on the bottom of the groove 40, the weld metal 60 is embedded in the groove 40, and the column flange 21 and the beam flange 31 are directly welded.

For example, when the steel frame structure receives an earthquake force, a tensile force acts on the beam 30 and a stress acts on the column flange 21 in the plate thickness direction.

On the other hand, stress is likely to concentrate on the shape notch 70 formed between the column flange 21 and the backing plate 50. There are various factors of stress concentration, but for example, it is due to the discontinuity in shape of the column flange 21 and the backing plate 50. Further, the panel zone surrounded by the columns 20 and the beams 30 undergoes shear deformation, whereby the column flange 21 is locally bent and deformed to widen the shape notch 70, thereby increasing stress concentration. In addition, the local deformation of the beam flange 31 caused by the slip of the web bolt joint expands the shape notch 70, thereby increasing the stress concentration.

Then, the material of the column flange 21 that is in contact with the steel material near the welding, that is, the weld metal 60 is deteriorated. When the welding heat affected zone 71 in which the material is deteriorated is in agreement with the direction orthogonal to the direction in which the stress acts (hereinafter referred to as the stress orthogonal direction), the bottom portion 70a of the shape notch 70 (hereinafter referred to as the notch bottom 70a). .) as a starting point along the welding heat-affected zone 71 and cracks may occur (break line P in the figure).

For example, in Patent Document 1, after using a backing metal having a surface on which a gently curved surface is formed, the pillar and the beam are welded, the backing metal is removed, and both the members of the pillar and the beam are covered. It is disclosed to form a welded portion having a continuous gentle curved surface. By increasing the effective cross-sectional area of the weld metal in this way, the stress acting on the beam-column joint is reduced.

Further, Patent Documents 2 and 3 disclose that a notch is formed on the surface of a backing metal used for welding a column and a beam, respectively. Even in such a case, the effective sectional area of the weld metal is increased, and the stress acting on the column-beam joint is reduced.

Further, in Patent Document 4, a diaphragm provided on a pillar is projected to the beam side, and a supporting portion that allows a lower flange of the beam to be mounted is provided on a protruding portion of the diaphragm. End tabs that restrict the positions of the flange widthwise are provided. By forming the end tab integrally with the diaphragm, the shape notch is eliminated, and the stress acting on the post-beam joint is reduced.

Moreover, in patent document 5, the thickening process is performed on the first steel material to be welded and the first steel material end portion and the second steel material end portion are butt-welded via a groove, It is disclosed that continuous makeup welding is performed on the butt welded portion in a predetermined range of the thickened portion of the steel material. Reinforcing the portion where stress concentrates in this way suppresses breakage.

Further, Non-Patent Document 1 discloses that the lower flange of the beam is welded by complete penetration welding using a rectangular groove, and then the backing metal is removed, the back is suspended, and then repair welding is performed. By removing the backing metal in this way, the welding defects that are likely to occur in the initial layer welding are eliminated, and the shape notch caused by the backing metal is eliminated, and the stress acting on the column-beam joint is reduced. ing.

JP-A-5-8033 JP-A-59-1094 JP, 2011-136350, A JP-A-6-240745 JP, 2003-117654, A

AISC358-10 Prequalified Connections for Special and Intermediate Steel Frames Frames for Seismic Applications, 2010, incl. Supplement No. 1

However, when the joining method described in Patent Document 1 is used, it is necessary to form a concave curved surface on the surface of the backing plate, and further it is necessary to remove the backing plate, which requires many processing steps and is costly.

Further, when the backing metal described in Patent Documents 2 and 3 is used, it is necessary to form a notch on the surface of the backing metal, and thus the number of processing steps is large and the cost is high.

In addition, when the column-beam joint section described in Patent Document 4 is used, complicated processing is required for the diaphragm, and thus the cost is high.

Further, when the joining method described in Patent Document 5 is used, it is necessary to subject the first steel material to pressure-intensifying processing, and further, it is necessary to carry out make-up welding after butt welding, resulting in many processing steps and cost.

Further, when the welding method described in Non-Patent Document 1 is used, the welding of the column-beam joint is performed at the construction site, and therefore the welding posture becomes upward during the repair welding, which complicates the construction procedure.

As described above, even if any of the column-beam joints described in Patent Documents 1 to 5 and Non-Patent Document 1 is used, the processing is complicated and the cost is high.

The present invention has been made in view of the above point, and the flange of the H-section steel column and the flange of the H-section steel beam are welded and joined by simple processing to suppress the breakage of the column-beam joint portion. The purpose is to

In order to achieve the above-mentioned object, the present invention provides a column-beam joint part in which a flange of an H-section steel column and a flange of an H-section steel beam are welded and joined together via a groove. Due to the backing metal provided at the bottom, the end located on the most column side in the shape notch formed between the backing metal and the flange of the column, in the weld metal embedded in the groove Located on the beam side of the end located on the most pillar side, the pillar is provided on the outer surface of the flange of the pillar facing the beam, and includes a protruding portion protruding toward the beam side, A backing metal is abutted on the beam side portion of the protrusion, the shape notch is formed between the backing metal and the protrusion, and the weld metal is on the flange side of the column. The groove surface is embedded in the groove formed by the flat outer surface of the flange of the post .

Before SL protrusion is fixed to the beam that faces the outer surface of the flange of the column, it may be another other backing strip from said backing strip. The other backing metal may be fillet-welded and fixed to the outer surface of the flange of the column, and the fillet-welded metal may be embedded in the groove together with the weld metal.

According to another aspect of the present invention, there is provided a column-beam joining method for welding a flange of an H-section steel and a flange of a beam of H-section steel by welding through a groove, and backing the bottom of the groove. In a shape notch formed between the backing metal and the flange of the column, which is caused by the backing metal in the welding process, has a welding process of providing gold and embedding a weld metal in the groove. The end located on the most pillar side is arranged on the beam side with respect to the end located on the most pillar side in the weld metal embedded in the groove, and before the welding step, with the beam in the flange of the pillar. Protrusions that protrude toward the beam are formed on opposing outer surfaces, and in the welding step, the weld metal is applied to the groove with the backing metal abutting against the beam-side surface of the protrusion. It is characterized by being embedded in .

Before SL protrusions, other backing strip that is different from the backing strip, formed by fixing and fillet welded to the beam that faces the outer surface of the flange of the column, in the welding process, the The weld metal may be embedded in the groove together with the fillet-welded metal in a state where the backing metal is in contact with another backing metal.

According to the present invention, in the structure of the H-shaped steel beam-column joint portion, the beam-column joint portion is positioned by shifting the shape notch to the beam side as compared with the end portion of the weld metal on the column side. The stress acting on the heat-affected zone of the column flange welding can be reduced, and breakage at the column-beam joint can be suppressed. Moreover, unlike the prior art, complicated processing is unnecessary, and the manufacturing cost can be reduced. Therefore, the column-beam joint portion can be efficiently manufactured.

It is explanatory drawing which shows the pillar and beam provided with the pillar-beam connection part concerning 1st Embodiment. It is explanatory drawing which shows the structure of the pillar-beam connection part concerning 1st Embodiment. It is explanatory drawing which shows the structure of the beam-column connection part concerning 1st Embodiment, (a) shows the whole structure of a beam-column connection part, (b) shows the enlarged view of a shape notch part. .. It is explanatory drawing which shows the structure of the beam-column joint part concerning 2nd Embodiment, (a) shows the whole structure of the beam-column joint part, (b) shows the enlarged view of a shape notch part. .. It is explanatory drawing which shows the structure of the beam-column joint part concerning 3rd Embodiment, (a) shows the whole structure of the beam-column joint part, (b) shows the enlarged view of a shape notch part. .. It is explanatory drawing which shows the cross-sectional dimension of the pillar (beam) in an Example. The analysis result of an Example is shown, (a) shows stress distribution, (b) shows strain distribution. It is explanatory drawing which shows the structure of the conventional beam-column joint part, (a) shows the whole structure of a column-beam joint part, (b) shows the enlarged view of a shape notch part.

Embodiments of the present invention will be described below with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configuration are designated by the same reference numerals, and a duplicate description will be omitted.

The present invention, in the beam-column joint, by providing the welding heat-affected zone with an angle to the column flange side from the stress orthogonal direction starting from the shape notch, or by locating the shape notch on the beam side. , Reduce the stress at the risk of fracture and further reduce strain. The welding heat-affected zone shown here refers to a portion of the column flange base material which is close to the weld metal in the column flange and whose material is changed by welding heat input. The stress acts in the plate thickness direction of the column flange, and the stress orthogonal direction is the direction orthogonal to the stress, that is, the material axis direction of the column flange.

FIG. 1 shows a column 20 and a beam 30 provided with a column-beam joint portion 10 according to the first embodiment of the present invention. The column-beam joint portion 10 is a joint portion that joins a beam flange 31 of a beam 30 formed of H-section steel to a column flange 21 of a column 20 formed of H-section steel, and is an upper beam. It is provided on both the flange 31 and the lower beam flange 31. Note that, in FIG. 1, other members are not shown in order to facilitate understanding of the present invention. For example, at the joint between the column 20 and the beam 30, the column flange 21 and the web 32 of the beam 30 may be bolted. Further, another beam may be joined to the web 22 of the pillar 20. In addition, the column 20 may be provided with a stiffener.

As shown in FIG. 2, in the column-beam joint portion 10, the column flange 21 facing the beam 30 is formed with a cutout portion 80 that is cut out in the plate thickness direction. The notch 80 includes a notch 80 a inclined from the outer surface of the column flange 21, and a notch 80 b extending in the material axis direction inside the column flange 21. The depth D of the notch 80 in the plate thickness direction, that is, the distance between the outer surface of the column flange 21 and the notch 80b is 2 mm or more. Further, in the cutout portion 80a, the inclination angle θ from the outer surface of the column flange 21 is 45 degrees or more.

Various methods can be used to form the cutout portion 80. For example, the outer surface of the column flange 21 may be cut, or the outer surface of the column flange 21 (a region of a welding initial layer portion described later) may be gouged.

Then, as shown in FIG. 3, a backing metal 50 is provided on the bottom of the groove 40 having a substantially rectangular cross section formed between the column flange 21 and the beam flange 31, and the groove 40 including the cutout portion 80 is provided. The weld metal 60 is embedded and completely melted and welded. In this way, the column-beam joint portion 10 is formed between the column flange 21 and the beam flange 31.

Also in the post-beam joint portion 10, a shape notch 70 due to the backing plate is formed between the column flange 21 and the backing plate 50, as in the conventional case shown in FIG.

On the other hand, in the column flange 21 that is in contact with the weld metal 60, the welding heat-affected zone 71 whose material has deteriorated is formed along the notch 80. That is, the welding heat-affected zone 71 includes a welding heat-affected zone 71a inclined from the outer surface of the column flange 21 along the notch 80a, and a welding heat-affected zone 71b extending along the notch 80b in the material axis direction. Composed of.

The welding heat-affected zone 71a is inclined from the stress orthogonal direction (corresponding to the material axis direction of the column 20) to the column flange 21 side starting from the end 70b located closest to the column 20 in the shape notch 70 (notch bottom 70a). Therefore, it is possible to reduce the stress in the welding heat affected zone 71a from the shape notch 70. Further, since the welding heat-affected zone 71b is located closer to the column flange 21 side than the end portion 70b of the shape notch 70, the stress in the welding heat-affected zone 71b can also be reduced. Since the welding heat affected zone 71 does not coincide with the stress orthogonal direction starting from the end 70b of the shape notch 70 as described above, the stress acting on the welding heat affected zone 71 can be sufficiently reduced, and the beam It is possible to suppress breakage in the joint portion 10.

Moreover, in this embodiment, since the depth D of the notch 80 is set to 2 mm or more, the stress acting on the welding heat affected zone 71 can be sufficiently reduced. The critical significance of setting the lower limit of the depth D of the cutout portion 80 to 2 mm will be described in Examples described later.

Further, in this embodiment, since the inclination angle θ of the cutout portion 80a is 45 degrees or more, the stress acting on the welding heat affected zone 71a can be dispersed, and the stress can be sufficiently reduced. it can. Further, since the inclination angle θ is 45 degrees or more, the weld metal 60 can be appropriately embedded in the cutout portion 80.

The weld metal 60 is harder than the base metal (that is, the pillar 20 and the beam 30). Therefore, compared with the base metal, the weld metal 60 is less likely to rupture inside from the shape notch 70 in the stress orthogonal direction.

Next, a method of joining the column 20 and the beam 30 through the column-beam joint portion 10 having such a configuration will be described. First, as shown in FIG. 2, the notch 81 is formed on the outer surface of the column flange 21 by cutting or gouging. In the case of cutting, the notch 81 is formed in the factory, and in the case of gouging, the notch 81 is formed at the construction site.

After that, after the backing plate 50 is assembled and welded to the beam flange 31, the column flange 21 is further assembled and welded to the backing plate 50. Thus, as shown in FIG. 3, the backing plate 50 is provided on the bottom of the groove 40.

After that, the weld metal 60 is embedded in the groove 40 including the cutout portion 80, and complete penetration welding is performed (welding process in the present invention). Then, the column-beam joint portion 10 is formed, and the column 20 and the beam 30 are thereby joined.

According to the present embodiment, it is possible to reduce the stress acting on the column/beam joint portion 10 and suppress the breakage in the column/beam joint portion 10. By suppressing the fracture in this way, the tensile force acting on the beam 30 due to, for example, seismic force can be appropriately transmitted to the column 20.

Moreover, the notch 80 can be formed in the column flange 21 by a simple process such as a cutting process or a gouging process, and the conventional complicated process is not required. Therefore, it is possible to easily form the column-beam joint portion 10, and it is possible to reduce the manufacturing cost. Especially in the case of cutting, since the notch can be processed in the factory, the work load at the construction site can be reduced, and the manufacturing accuracy can be easily secured by machining. Further, in the case of gouging processing, it is a work at a construction site, but it is possible to perform manufacturing processing without a large-scale device such as a cutting machine.

Further, the formation of the cutout portion 80 and the installation of the backing plate 50 can be prepared in advance at a steel frame processing factory, and the work at the construction site can be limited to the main welding work. Therefore, the construction period can be shortened.

Next, with reference to FIG. 4, a configuration of the column/beam joint portion 10 according to the second embodiment of the present invention will be described.

The column 20 includes a protrusion 23 on the outer surface of the column flange 21 that faces the beam 30. The projecting portion 23 is formed in a substantially rectangular cross section that is long in the material axis direction of the column 20, and in this embodiment, it projects from the outer surface of the column flange 21 in the direction in which the beam 30 is located. It is extended in the width direction of the column flange 21 by any means such as carving. The backing plate 50 is in contact with the surface of the protruding portion 23 on the beam 30 side. On the other hand, the column flange 21 does not have the cutout portion 80 provided in the first embodiment.

In the beam-column joint portion 10 of the present embodiment, the shape notch 70 is formed between the backing plate 50 and the protruding portion 23. Therefore, in the groove 40, the groove surface on the side of the column flange 21 is formed by the flat outer surface of the column flange 21 (that is, the outer surface without the cutout portion 80 as in the first embodiment), and the welding is performed. The metal 60 is embedded in this groove 40.

On the other hand, the welding heat-affected zone 71 is formed along the flat outer surface of the column flange 21, and the welding heat-affected zone 71 is in a stress orthogonal direction starting from the end 70b of the shape notch 70 located closest to the column 20. It does not match. Therefore, it is possible to enjoy the same effect as that of the first embodiment, that is, it is possible to sufficiently reduce the stress acting on the welding heat-affected zone 71 and suppress the breakage in the beam-column joint section 10.

Here, in the method of joining the column 20 and the beam 30 of the present embodiment, first, as shown in FIG. 4, the protrusion 23 is formed on the outer surface of the column flange 21, and then the backing plate 50 is attached to the beam flange 31. Assemble and weld. Any of the formation of the protrusions 23 and the assembly welding of the backing plate 50 may be performed first. Then, the backing plate 50 is assembled and welded to the protrusion 23. Thus, the groove 40 is formed. After that, the weld metal 60 is embedded in the groove 40, and complete penetration welding is performed (welding process in the present invention). Then, the column-beam joint portion 10 is formed. In the present embodiment, it is not necessary to form the notch 80 in the column flange 21 as in the first embodiment, so that the column 20 can be formed relatively easily.

Next, with reference to FIG. 5, the configuration of the beam-column joint portion 10 according to the third embodiment of the present invention will be described.

The column 20 is provided with another backing plate 90 as the protrusion 23 in the second embodiment on the outer surface of the column flange 21 that faces the beam 30. The other backing plate 90 in this embodiment is a rectangular parallelepiped formed in a substantially rectangular cross section that is long in the material axis direction of the column 20, and is fixed to the outer surface of the column flange 21 by fillet welding. The backing plate 50 is in contact with the surface of the other backing plate 90 on the beam 30 side.

Therefore, in the groove 40, the groove surface on the side of the column flange 21 is formed by the flat outer surface of the column flange 21 (that is, the outer surface having no cutout as in the first embodiment), and the weld metal 60 is embedded in this groove 40. At this time, the metal of the fillet weld 91 fixing the backing plate 90 to the column flange 21 is embedded in the groove together with the weld metal 60 embedded in the groove 40.

Note that the other configurations of the column-beam joint unit 10, that is, the web 22 of the column 20, the web 32 of the beam 30, the backing plate 50, etc., are the same as those of the second embodiment shown in FIG. It is substantially the same as the configuration of the connection part 10.

In the beam-column joint portion 10 of the present embodiment, the shape notch 70 is formed between the backing plate 50 and another backing plate 90. On the other hand, the welding heat-affected zone 71 is formed along the outer surface of the column flange 21, and the welding heat-affected zone 71 does not coincide with the stress orthogonal direction starting from the end 70b located closest to the column 20 in the shape notch 70. .. Therefore, it is possible to enjoy the same effect as that of the above-described embodiment, that is, it is possible to sufficiently reduce the stress acting on the welding heat-affected zone 71 and suppress the breakage in the column-beam joint section 10.

Here, in the method of joining the column 20 and the beam 30 of the present embodiment, first, as shown in FIG. 5, another backing metal 90 is fixed to the outer surface of the column flange 21 by fillet welding. After forming the protrusion, the backing plate 50 is assembled and welded to the beam flange 31. Any of the formation of the other backing metal 90 and the assembling and welding of the backing metal 50 may be performed first. Then, the backing plate 50 is assembled and welded to another backing plate 90. Thus, the groove 40 is formed. After that, the weld metal 60 is embedded in the groove 40 together with the metal of the fillet weld 91, and complete penetration welding is performed (welding process in the present invention). Then, the column-beam joint portion 10 is formed. In the present embodiment, it is not necessary to form the cutout portion 80 as in the first embodiment, and since it is possible to install another backing plate 90 on site, workability is improved. It is extremely high, and the construction period can be shortened.

Since the other backing metal 90 provided on the pillar is fixed to the pillar flange by the fillet weld 91, it is possible to suppress the concentration of stress between the pillar flange 21 and the other backing metal 90. it can.

The preferred embodiment of the present invention has been described above with reference to the accompanying drawings, but the present invention is not limited to such an example. It is obvious to those skilled in the art that various changes or modifications can be conceived within the scope of the idea described in the claims, and naturally, they also belong to the technical scope of the present invention. Understood.

Examples of the present invention will be described below. The column-beam joint portion 10 shown in FIG. 3 was used as the present example, and the column-beam joint portion 10 shown in FIG. 8 was used as the comparative example. Then, these column-beam joints 10 were modeled by finite element analysis, and stress and strain were analyzed under the following conditions.

As shown in FIG. 6, the column 20 has a cross-sectional dimension of H1=474.6 mm, width B1=424.0 mm, flange 21 plate thickness tf1=77.0 mm, and web 22 plate thickness. The tw1 is 47.6 mm and the fillet r1 is 15.2 mm. Regarding the cross-sectional dimensions of the beam 30, the width B2 thereof is 300 mm, and the plate thickness tf2 of the flange 31 is 32 mm. The tensile strength of each of the pillar 20 and the beam 30 is 490 MPa.

In the column-beam joint 10 shown in FIGS. 3 and 8, the distance between the outer surface of the column flange 21 and the tip of the beam flange 31 is 6 mm, and the angle of inclination of the beam flange 31 is 45 degrees. The backing plate 50 has a height of 12 mm and a width of 25 mm. Then, the depth D of the cutout portion 80 was changed to 0 mm (case 1), 2 mm (case 2), and 4 mm (case 3), and a tensile force was applied to the beam flange until the beam flange became plastic. That is, Case 1 is the comparative example shown in FIG. 8, and Cases 2 and 3 are the examples shown in FIG.

In this example, the stress and strain along the weld heat affected zone 71 (boundary of the weld metal 60) from the shape notch 70 after the beam flange was plasticized were investigated. The analysis result is shown in FIG. FIG. 7A shows an equivalent stress distribution, the vertical axis shows the position from the shape notch 70, and the horizontal axis shows the equivalent stress of the welding heat affected zone 71. FIG. 7B shows the equivalent plastic strain distribution, the vertical axis represents the position from the shape notch 70, and the horizontal axis represents the equivalent plastic strain of the welding heat affected zone 71.

Referring to FIG. 7, in case 1 which is a comparative example, the stress is large and the strain is large. On the other hand, in the cases 2 and 3 which are the examples of the present invention, the stress and the strain are greatly reduced immediately after leaving the bottom of the notch. Therefore, according to the present invention, it has been found that the stress acting on the beam-column joint portion 10 can be reduced and the breakage in the beam-column joint portion 10 can be suppressed. In addition, since the analysis results of Case 2 and Case 3 do not change significantly, it was found that a sufficient effect can be enjoyed if the depth D of the cutout portion 80 is 2 mm or more.

INDUSTRIAL APPLICABILITY The present invention can be applied to a beam-column joint portion in which a H-shaped column flange and a beam flange are welded and joined in a steel structure to which seismic force acts. Further, it can be applied as it is to a beam/column joint in a steel frame structure in which seismic force need not be considered.

10 column beam connection part 20 column 21 flange 22 web 23 protrusion 30 beam 31 flange 32 web 40 groove 50 backing metal 60 weld metal 70 shape notch 71 (71a, 71b) welding heat affected zone 80 (80a, 80b) Notch 90 Other backing metal 91 Fillet welding

Claims (5)

A column-beam joint part in which a flange of an H-section steel and a flange of a beam of H-section steel are welded and joined together via a groove,
Due to the backing metal provided at the bottom of the groove, the end of the shape notch formed between the backing metal and the flange of the pillar that is closest to the pillar is embedded in the groove. Located on the beam side of the end of the weld metal that is located on the most pillar side ,
The pillar is provided on an outer surface of the flange of the pillar facing the beam, and includes a protrusion that protrudes toward the beam,
The backing plate is brought into contact with the beam-side portion of the protrusion,
The shape notch is formed between the backing plate and the protrusion,
The beam-column joint portion, wherein the weld metal is embedded in the groove formed by the flat outer surface of the flange of the column on the groove side of the column. The column-beam finish according to claim 1 , wherein the protrusion is another backing metal other than the backing metal fixed to an outer surface of the flange of the column facing the beam. Mouth. The other backing plate is fillet-welded and fixed to the outer surface of the flange of the column,
The beam-column joint portion according to claim 2 , wherein the fillet-welded metal is embedded in the groove together with the weld metal. A column-beam joining method for joining a flange of an H-section steel and a flange of a H-section steel beam through a groove,
Providing a backing metal on the bottom of the groove, and having a welding step of embedding a weld metal in the groove,
In the welding step, a weld metal that is caused by the backing metal and has an end located on the most pillar side in a shape notch formed between the backing metal and the flange of the pillar is embedded in the groove. most of the end portion located on the pillar side is disposed on the beam side in,
Before the welding step, on the outer surface of the flange of the column facing the beam, a protruding portion protruding toward the beam is formed,
In the welding step, the beam- to-column joining method is characterized in that the weld metal is embedded in the groove in a state where the backing metal is in contact with the beam-side surface of the protrusion . The projecting portion is formed by fixing another backing metal different from the backing metal by fillet-welding and fixing it to the outer surface of the flange of the column facing the beam.
In the welding process, being in contact with said backing strip to said other backing strip, characterized by embedding the weld metal to the GMA with the fillet weld metal, claim 4 The beam-column joining method described in.

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