JP5115012B2 - Column and beam welded joint structure - Google Patents

Description

  The present invention relates to a welded joint structure of a column and a beam used when joining a steel column such as a square steel pipe column or a welded box column and a steel beam such as an H-shaped steel or an I-shaped steel having parallel flanges above and below by welding. It is about.

  When joining steel pillars, such as a square steel pipe pillar and a welding box pillar, and steel beams, such as H-shape steel and I-shape steel, joining is performed using welding (for example, refer to patent documents 1). As an example, a welded joint structure as shown in FIGS. 3 and 4 is employed. By the way, when welding steel columns such as steel pipe columns and steel beams such as H-shaped steel, a diaphragm is installed on the steel columns to increase the rigidity of the welded joints and to smooth the transmission of stress. It is common to weld the flange (beam flange) of a steel beam (beam bracket) to the diaphragm. As a method of installing the diaphragm, a through-diaphragm method in which the diaphragm is installed through the steel tube column or a steel tube column. There is an outer diaphragm method in which a diaphragm is installed on the outer periphery of the outer periphery, and FIG. 3 and FIG.

  First, FIG. 3 shows a case of factory welding in which a through diaphragm and a beam flange are welded in advance in a factory, (a) is a side view, (b) is a view taken along arrow B-B in (a), (c) ), The height position of the upper and lower beam flanges 2a and 2a at the joint between the steel column 1 of the square steel pipe column and the steel beam (beam bracket) 2 of the H-shaped steel as shown in FIG. Correspondingly, diaphragms 3 and 3 are installed through the steel column 1. And, when joining the end portion of the beam flange 2a to the through diaphragm 3 by welding, a groove 4 is provided at the connection end portion of each beam flange 2a, and scallops 5 are provided above and below the connection end portion of the beam web 2b, The backing metal 50 that forms the bottom of the groove 4 is temporarily welded to the beam flange 2a, and is butted against the diaphragm 3 through the beam flange 2a, and then is welded to the groove 4 (butt welding). ) 7, the beam flange 2 a is welded to the through diaphragm 3. At the same time, the beam web 2 b is fixed to the skin plate 1 a of the steel column 1 by fillet welding 6.

  Note that end tabs 51 are provided at both ends of the backing metal 50 in the beam width direction, and welding to the end tabs 51 prevents welding defects at the beam width ends.

Next, FIG. 4 is a case of on-site welding in which the through diaphragm and the beam flange are welded on site, (a) is a side view, (b) is a view taken along the line BB of (a), and (c). As shown in the detailed view of part A of FIG. 5A, the gusset plate 8 is previously attached to the skin plate 8 of the steel column 1 by fillet welding or the like, and a backing metal 50 is attached to the flange 2a of the steel beam 2. Attach the steel beam 1 between the steel columns 1 and 1 at the site, temporarily fix the beam web 2b to the gusset plate 8 with bolts 9, and then perform butt welding 7 of the through diaphragm 3 and the beam flange 2a. After the end of welding, the bolt 9 is finally tightened to join the steel column 1 and the steel beam 2.
Japanese Patent Laid-Open No. 3-176526

  However, during the 1995 Hyogoken-Nanbu Earthquake, the conventional welded joint as described above suffered a lot of damage against the bending moment. The damage consists of various cracks and fractures such as welds at the beam end, near the scallop, and near the end tab. The main cause is due to the welded structure itself, such as a defect in the weld, a scalloped shape, and a shape discontinuity due to the end tab, in addition to the material toughness reduction. In particular, when the column has a hollow cross section such as a square steel pipe, the beam web 2b often does not work effectively, and when the force concentrates on the beam flange 2a, a crack generated from the scallop bottom or end tab develops, There were many examples in which the beam flange 2a was broken.

  The present invention has been made in view of the above, and in a welded joint structure in which a diaphragm installed on a steel column and a flange end of a steel beam are joined by butt welding, the beam flange and the diaphragm are butt-matched with a simple configuration. It is an object of the present invention to provide a welded joint structure between a column and a beam that can reinforce a welded joint and can surely prevent breakage of a beam flange against a bending moment.

  In order to solve the above problems, the present invention has the following features.

  [1] In a welded joint structure in which a diaphragm installed on a steel column and a flange end of the steel beam are joined by butt welding when joining a steel column and a steel beam having an H-shaped cross section, the butt welded portion is straddled. The connection plate is extended from the steel column side to the steel beam side, and the connection plate is attached to the flange of the steel beam and fixed by welding, and the steel column side of the connection plate is fixed to the diaphragm by welding. This is a welded structure of columns and beams.

  [2] A predetermined number of holes are respectively provided on the steel beam side and the steel column side of the connection plate, and the holes are filled with a weld metal, and the connection plate is fixed to the flange of the steel beam and the diaphragm. The welded joint structure of a column and a beam according to the above [1].

  [3] The welded joint structure between a column and a beam according to [1] or [2], wherein the connecting plate protrudes outward from the width end portion of the flange of the steel beam.

  In the present invention, in a welded joint structure in which a diaphragm installed on a steel column and a flange end of a steel beam with an H-shaped cross section are joined by butt welding, the diaphragm extends from the steel column side to the steel beam side across the butt weld. Since the existing connecting plate is fixed to the beam flange and diaphragm by welding, the butt weld joint can be reinforced with a simple configuration, and the beam flange can be reliably prevented from breaking due to bending moment. it can.

  A welded structure of a column and a beam according to an embodiment of the present invention will be described below. Here, a description will be given by taking a through-diaphragm welding connection structure as an example.

  FIG. 1 shows a welded joint structure between a column and a beam according to a first embodiment of the present invention, which is a welded joint structure by factory welding in which a through diaphragm and a beam flange are welded in advance in a factory. In FIG. 1, (a) is a side view, (b) is a view taken along the line BB of (a), (c) is a view taken along the line CC of (a), and (d) is an A view of (a). FIG.

  FIG. 2 shows a welded joint structure between a column and a beam according to a second embodiment of the present invention, which is a welded joint structure by field welding in which a through diaphragm and a beam flange are welded on site. 2, (a) is a side view, (b) is a view taken along the line B-B of (a), (c) is a view taken along the line CC of (a), and (d) is an A view of (a). FIG.

  As shown in FIGS. 1 and 2, in any of the embodiments, in the welded joint structure shown in FIG. 3 or FIG. 4, the butt weld 7 is used to reinforce the butt weld 7. The connecting plate 10 is installed so as to straddle.

  In other words, in the first and second embodiments of the present invention, a steel beam (H-shaped steel or I-shaped steel is parallel to a through diaphragm 3 installed on a steel column (closed-section column such as a steel pipe column) 1. In a welded joint structure in which the end of the flange 2a of the flange 2) is joined by butt welding using a backing metal 50, the steel column side is connected to the steel beam side so as to straddle the butt weld 7 The plate 10 is extended, the connecting plate 10 is attached to the beam flange 2a and fixed by welding, and the end of the connecting plate 10 on the steel column side is passed through and fixed to the diaphragm 3 by welding. The weld joint 7 at the end of 2a is reinforced.

  Here, the connecting plate 10 has, for example, a width in the beam width direction that is a length obtained by combining the conventional backing metal 50 and both end tabs 51, and a length in the beam material length direction is the number of the widths of the backing metal 50. A rectangular plate that is doubled. Incidentally, here, the connecting plate 10 is divided into two in the beam width direction. The thickness of the connecting plate 10 is equal to or greater than the thickness of the backing metal 50. Note that the length and thickness of the connecting plate 10 in the beam material length direction may be appropriately determined from the beam length of the steel beam 2 and the flange thickness.

  In addition, a slit 11 that is slightly larger than the welding width is formed in a portion of the connecting plate 10 that straddles the butt weld portion 7 so that the connecting plate 10 does not interfere with the butt weld portion 7.

  Such a connecting plate 10 is fixed to the beam flange 2a of the steel beam 2 and the through diaphragm 3 of the steel column 1 by welding. At that time, a predetermined number of holes 10a are provided in the connecting plate 10 along the length direction of the steel beam, and the holes 10a are filled and welded 12 so that the connecting plate 10 is fixed to the beam flange 2a and connected. A predetermined number of holes 10 a are provided at the end of the plate 10 on the steel column side, and the holes 10 a are filled and welded 12 so that the connecting plate 10 is passed through and fixed to the diaphragm 3.

  The shape of the hole 10a provided in the connecting plate 10 can be changed depending on the strength required by the designer for the connecting plate 10, and may be not only a perfect circle but also an ellipse. Any shape. Further, the number of holes 10a may be determined as appropriate so that a desired bonding strength can be obtained. Further, as shown in FIGS. 1 and 2, the connecting plate 10 may be not only divided into two but also one.

  In the welded joint structure as described above, in the case of the first embodiment (factory welding) shown in FIG. 1, after the butt welding of the steel column 1 and the steel beam 2 is performed, the connecting plate 10 is filled and welded 12. Thus, the construction procedure is to fix to the beam flange 2 a of the steel beam (beam bracket) 2 and the through diaphragm 3 of the steel column 1.

  Incidentally, in the case of factory welding, since welding can be performed in an optimal welding posture such as downward welding or sideways welding, the connection plate 10 is positioned on the lower surface side in the lower beam flange 2a, and the upper beam flange 2a and A vertically symmetrical structure can be obtained.

  Since the bending moment is transmitted from the diaphragms 3 and 3 to the steel column 1 through the upper and lower flanges 2a and 2a, and the shearing force is transmitted to the steel column 1 through the beam web 2b, the beam web 2b has a fillet. It is fixed to the skin plate 1a of the steel column 1 by welding.

  On the other hand, in the case of the second embodiment (field welding) shown in FIG. 2, the gusset plate 8 is previously attached to the skin plate 8 of the steel column 1 by fillet welding or the like, and the flange 2a of the steel beam 2 is attached to the flange 2a. The backing metal 50 is attached, the steel beam 2 is suspended between the steel columns 1 and 1 at the site, the beam web 2b is temporarily fixed to the gusset plate 8 with the bolt 9, and the through diaphragm 3 and the beam flange 2a are butted together. Welding 7 is performed, and after completion of welding, the bolt 9 is finally tightened to join the steel column 1 and the steel beam 2. Thereafter, similarly to the case of the first embodiment (factory welding), the connecting plate 10 is fixed to the diaphragm 3 through the beam flange 2a by filling welding.

  In the field welding, since downward welding is generally preferable, the connection plate 10 is positioned on the upper surface side in the lower beam flange 2a to have the same positional relationship as the upper beam flange 2a. Thereby, it is possible to perform the filling welding 12 downward also in the lower beam flange 2a side.

  In the welded structure of a column and a beam according to the embodiment of the present invention configured as described above, the bending moment is transmitted from the diaphragm 3 to the steel column 1 through the beam flange 2a, and the shearing force is transmitted to the beam. It is transmitted to the skin plate 1a of the steel column 1 through the web 2b. At this time, the joining end portion of the beam flange 2a is reinforced by the connection plate 10, so that the beam flange 2a is reliably broken against the bending moment. Can be prevented.

  Furthermore, as shown in FIG. 1 and FIG. 2, the stress from the steel beam 2 can flow smoothly into the steel column 1 by fixing the connecting plate 10 so as to protrude from the width end of the beam flange 2 a. Further effects can be obtained.

  In addition, in said embodiment, although the case where a steel beam is attached to a steel column only from one side is shown, it cannot be overemphasized that a plurality of steel beams are attached according to an outer pillar, a middle pillar, and an inner pillar. .

  Further, in the above-described embodiment, the through-diaphragm weld joint structure has been described as an example, but the present invention can also be applied to an outer diaphragm weld joint structure.

  Furthermore, in the above-described embodiment, the description is limited to closed cross-section columns such as steel pipe columns, but the present invention is also applicable to open cross-section columns such as H-shaped steel columns.

It is a figure which shows the welding junction structure (factory welding) of the pillar and beam which concerns on the 1st Embodiment of this invention. It is a figure which shows the welding junction structure (field welding) of the pillar and beam which concerns on the 2nd Embodiment of this invention. It is a figure which shows the example of the welding junction part structure (factory welding) of the conventional column and a beam. It is a figure which shows the example of the welding junction part structure (field welding) of the conventional column and a beam.

Explanation of symbols

1 Steel columns (closed-section columns such as steel pipe columns)
1a Steel column skin plate 2 Steel beam (beam with parallel flanges of H-shaped steel and I-shaped steel)
2a Beam flange 2b Beam web 3 Through diaphragm 4 Groove 5 Scallop 6 Fillet weld (fillet weld)
7 Butt welding (butt welding)
8 Gusset plate 9 Bolt 10 Connection plate 10a Hole 11 Slit 12 Fill welding (fill weld)
50 backing metal 51 end tab

Claims (2)

  When joining a steel column and a steel beam with an H-shaped cross section, in a welded joint structure in which the diaphragm installed on the steel column and the flange end of the steel beam are joined by butt welding, the steel column straddles the butt weld The connection plate is extended from the side to the steel beam side, the connection plate is fixed to the flange of the steel beam by welding, and the steel column side of the connection plate is fixed to the diaphragm by welding. A column characterized by providing a predetermined number of holes on each of the steel beam side and the steel column side of the plate, filling the holes with weld metal, and fixing the connecting plate to the flange of the steel beam and the diaphragm; Beam welded joint structure. The column and beam welded joint structure according to claim 1, wherein the connection plate protrudes outward from the width end of the flange of the steel beam and is fixed.

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