JP5754262B2 - Beam-column joint structure - Google Patents

Description

  The present invention relates to a column beam joint structure for welding a through-diaphragm of a steel column such as a square steel pipe column or a weld box column and a steel beam such as an H-shaped steel or an I-shaped steel having parallel flanges in the vertical direction.

  When a bending moment (sometimes called bending) is applied to a beam-to-column welded joint where a steel beam made of H-section steel is welded to a steel column made of a closed-type cross-section column such as a steel pipe column or welded box column, Is prone to damage.

  FIG. 9 shows the moment distribution M near the beam end weld and the beam end weld, and FIG. 9B shows the moment distribution M near the beam end weld of the structure shown in FIG. In the vicinity of the welded portion of the beam end (the welded portion 40 of the diaphragm (also called through diaphragm) 3 and the bracket (also called the steel beam) 2), the moment is maximized, and the stress in the vicinity of the welded portion 40 is maximized. The beam side of the beam end welded portion is coupled to the steel beam 2 by a gusset 12 with bolts 9.

  Further, the axial force of the beam flange corresponding to the moment is transmitted to the square steel pipe column via the beam flange 2 c of the bracket 2 and the diaphragm 3. When the column has a hollow cross section such as a square steel pipe, the beam web often does not work effectively, and the force acts on the beam flange more.

  At this time, stress tends to concentrate on the width end portion of the welded portion 40 (the flange width end portion of the bracket 2) as a force flow, and weld defects are likely to occur in this portion, so when the beam is deformed. Is likely to cause a destructive phenomenon at the weld.

  Therefore, Patent Document 1 proposes a beam-to-column welded joint using a widened flange at the beam end. FIG. 8 shows the case of a welded assembly type H-section steel, but it requires a steel plate with a large area and the yield is poor. Moreover, the process becomes somewhat complicated for the H-section steel having parallel flanges on the upper and lower sides. In order to widen the beam end with the rolled H-shaped steel, it is necessary to prepare a rolled H-shaped steel with a wide width and cut the flange so as to have a predetermined shape.

  FIG. 7 shows a case where a triangular horizontal rib plate 11 is welded to the flange side surface of the beam flange 2a to widen the beam end portion, but the horizontal rib plate 11 is likely to be warped or twisted due to welding heat. Furthermore, the flange material deteriorates due to the influence of welding heat or a welding defect occurs at the end (rib tip) of the horizontal rib plate on the beam center side. For this reason, there is a risk that the beam 2 may brittlely break near the tip of the rib.

  In addition, Patent Document 2 discloses that even when a steel frame having a small cross section is used for the beam from the economical viewpoint as a beam-to-column connection structure of a steel-framed column beam frame, the beam end portion where the maximum stress is generated is not broken. Describes joining a cover plate to the top of the beam flange.

  Although various joint structures have been proposed as described above, the welded joint structures shown in FIGS. 6 and 5 are often used in actual construction. FIG. 6 shows a case where the steel beam (beam bracket) 2 grooved on the beam flange 2a is welded to the steel column 1 in the case of factory welding (FIGS. 6A and 6C). The end of the beam bracket 2 on the side of the steel pipe column 1 is processed so that the beam flange 2a and the through diaphragm 3 that reinforces the steel column 1 are completely melted and joined by welding.

  Therefore, the groove 4 of the beam flange 2a is processed so that a root gap is obtained in the groove portion of the diaphragm 3 through the beam flange 2a in a state where the beam web 2b is in contact with the steel column 1 (FIG. 6). (B)).

  The steel beam (beam bracket) 2 and the steel pipe column 1 are welded in a state where the backing metal 50 is tack welded to the beam flange 2a by fillet welding, but the welding is performed at the welded portion of the steel pipe column 1 and the beam web 2b. As possible, scallops 5 are formed above and below the beam web 2b. In addition, the end tab 51 is provided in the both ends of the beam width direction of the backing metal 50, and the welding defect in the beam width end part is prevented by welding to this end tab.

  FIG. 5 shows a case of on-site welding, and a gusset plate 8 that holds the steel beam 2 in advance is attached to the steel column 1 by welding so that a steel beam 2 can be suspended between the steel columns 1 and 1 to form a column beam structure. (FIG. 5A).

  After the beam web 2b sandwiched between the gusset plates 8 is temporarily fixed with bolts 9, butt welding 7 is performed. After the welding is finished, the bolts 9 are finally tightened to join the steel column 1 and the steel beam 2. Also in the case of field welding, the end on the steel pipe column 1 side of the steel beam (bracket) 2 is processed so that the beam flange 2a and the through diaphragm 3 that reinforces the steel column 1 are joined by complete penetration welding. However, the groove 4 of the beam flange 2a is processed so that a downward welding operation is possible (FIG. 5B).

JP-A-11-210158 JP 2010-90595 A

  However, the conventional welded joint shown in FIGS. 5 and 6 suffered much damage when a strong bending moment (sometimes referred to as bending) was applied in the 1995 Hyogoken-Nanbu Earthquake. The damage is due to the occurrence and fracture of various cracks in the welded end of the beam, in the vicinity of the scallop, near the end tab, etc., in addition to the deterioration of the toughness of the material, defects in the weld, scalloped shape, end tab and through diaphragm 3 and beam flange This was due to the welded structure itself, such as a discontinuity in shape due to the difference in plate thickness 2a.

  In particular, when the column has a hollow cross section such as a square steel pipe, the beam web 2b often does not effectively contribute to the beam end strength, and stress concentrates on the beam flange 2a, so that a crack generated from the scallop bottom or the end tab is generated. A number of examples of progress and breakage of the beam flange 2a were observed.

  The present invention has been made in view of the above-mentioned damage state in the beam-column joint, and prevents the occurrence of weld defects in the welded joint between the column side and through diaphragm and beam flange, and the beam end is reinforced. An object of the present invention is to provide a beam-column joint structure capable of preventing the beam flange from being broken even when bending is caused by an earthquake or the like.

The object of the present invention can be achieved by the following means.
(1) A beam-to-column connection structure in which beams made of shaped steel having upper and lower flanges are welded to a steel column, wherein the steel column and the beam are joined by a steel column beam flange welded joint and a steel column beam A web weld joint,
The steel column beam flange welded joint is a joint obtained by completely melting and welding the groove part of the beam flange and the plate-like member joined to the outside thereof and a through diaphragm of the steel column,
The steel column beam web welded joint is a welded portion where the butted portion of the steel column and the web of the beam is welded,
The beam web is provided with scallops for welding the steel column beam flange welded joint and the steel column beam web welded joint,
The plate-like member is a taper plate that linearly decreases in thickness from a thick part to a thin part, has a plate width substantially the same as the flange width of the beam, and the end on the steel column beam flange welded joint side is A column having an appropriate length on the beam side and fillet welded to the beam flange as a thick portion of a plate thickness obtained by subtracting the plate thickness of the flange of the beam from the plate thickness of the through diaphragm Beam joint structure.
(2) The plate member has a portion where the plate thickness decreases in a cross section excluding both ends in the plate length direction, has a plate width substantially the same as the flange width of the beam, and the steel pipe column beam flange weld The thickness of the end portion on the joint side is a plate thickness obtained by subtracting the plate thickness of the flange of the beam from the plate thickness of the through-diaphragm, and is fillet welded to the beam flange with an appropriate length on the beam side. The column beam connection structure according to (1), which is characterized.

  According to the present invention, it is possible to prevent the beam flange from being broken even if a strong bending moment due to a large earthquake acts on the column beam connection structure, which is extremely useful in the industry.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the case of factory welding with the beam-column joining structure which concerns on one Example of this invention, (a) is a side view, (b) is the A section detailed drawing of (a), (c) is (a). B-B arrow view, (d) is a cc arrow view of (a). The figure which shows the other groove shape in the column beam junction structure shown in FIG. The figure which shows the other plate-shaped member in the beam-column joining structure shown in FIG. It is a figure explaining the case of field welding in the column beam connection structure concerning other examples of the present invention, (a) is a side view, (b) is the A section detailed drawing of (a), (c) is (a). BB arrow view of (a), cc arrow view of (a). It is a figure which shows the case of field welding with the welding joint part structure of the conventional pillar and beam, (a) is a side view, (b) is the A section detail drawing of (a), (c) is B- of (a). B arrow view. It is a figure which shows the case of the factory welding of the welding joint part structure of the conventional pillar and beam, (a) is a side view, (b) is the A section detail drawing of (a), (c) is B- of (a). B arrow view. Conventional example (column beam welded joint using a flange with a triangular horizontal rib plate welded to the flange side of the bracket at the beam end) Conventional example (column beam welded joint using a widened flange at the beam end) (A) is an example of a beam end welding part, (b) is a figure explaining the moment distribution M of the said beam end welding part vicinity.

  The column beam connection structure according to the present invention is a connection structure in which a beam flange of a steel beam reinforced with a tapered plate-like member is welded to a side surface or through diaphragm of a steel column by complete penetration welding.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a case where a beam-column joint structure according to an embodiment of the present invention is manufactured by factory welding, FIG. 1 (a) is a side view of a beam-column joint, and FIG. 1 (b) is FIG. FIG. 1C is a view for explaining a welding joint part in a detailed view of A part of FIG. 1B, and FIG. 1 (d) is a view taken along the line cc in FIG. 1 (a) and illustrates a state in which the beam web is attached to the steel column.

  In these drawings, 1 is a steel column, 1a is a skin plate, 2 is a steel beam, 2a is a beam flange, 2b is a beam web, 3 is a through diaphragm, 4 is a groove, 5 is a scallop, 6 is a fillet weld, 7 is a butt weld, 10 is a plate-like member, and 50 is a backing metal.

  The joint between the steel column 1 and the steel beam 2 shown in the figure includes (a) a steel column beam flange welded joint where the through diaphragm 3 of the steel column 1 and the beam flange 2a are welded together, and (b) the steel column 1 and the beam web 2b. Steel beam-to-beam web welded joints.

  The steel column beam flange welded joint is a joint in which the plate-like member 10 joined to the outer side of the beam flange 2a (opposite side of the beam web 2b) and the beam flange 2a are welded to the diaphragm 3, and through the diaphragm 3 side. The beam-shaped groove 4 in which the beam flange 2a and the plate-like member 10 side are grooved obliquely in a straight line is welded. The beam flange 2a and the plate-like member 10 are welded.

  The plate-like member 10 welded to the outside of the beam flange 2a (the surface opposite to the beam web 2b) is a taper plate that linearly decreases in thickness from the thick part to the thin part. Have

  It is assumed that the plate member 10 has a thick portion at the end of the steel pipe column beam flange welded joint, and the plate thickness of the diaphragm 3 is subtracted from the plate thickness of the diaphragm 3 through the plate thickness. The length of the plate member 10 is set to an appropriate length.

  Since the groove 4 has a root gap to which the backing metal 50 is applied, and the plate thickness of the through diaphragm 3 and the total plate thickness of the plate member 10 joined to the beam flange 2a are substantially equal over the weld length, A complete penetration welding butt weld 7 having no weld defects is obtained. When the thickness of the thick portion of the plate-like member 10 is thin, welding defects are unlikely to occur, and therefore groove processing that is an extension of the groove surface of the beam flange 2a applied to the end portion 10a is omitted (FIG. 2). .

  The length of the plate-like member 10 in the beam length direction may be appropriately determined according to the desired beam rigidity, and is not particularly defined in the present invention, but is several times the width of the backing metal 50 in the beam length direction. Is desirable.

  FIG. 3 shows an example of the plate-like member 10 that is used when reinforcing the beam end portion and making a critical cross section preceded by yielding from the beam end portion toward the center of the beam. In the plate-like member 10 having a substantially inverted triangular cross section in the plate length direction, a portion that becomes a critical cross section is a portion that becomes a flat top in the substantially inverted triangular cross section, and a portion that has a minimum plate thickness in the cross section in the plate length direction. It is. In this case as well, the plate width is substantially the same as the flange width of the beam, and the plate thickness is obtained by subtracting the plate thickness of the beam flange from the plate thickness of the diaphragm through the plate thickness of the steel pipe column beam flange weld joint side. The plate-like member 10 has an appropriate length on the beam side and is fillet welded to the beam flange.

  The steel beam-to-beam flange welded joint of the beam-to-column welded joint according to the present invention is a complete penetration welded part, and there is no discontinuous part of the plate thickness in the vicinity of the welded part of the through diaphragm 3 and the beam flange 2a. Excellent.

  The steel pipe column beam web welded joint is a joint part in which the beam web 2b is welded to the skin plate 1a of the steel pipe column 1 by fillet welding 6, and a groove having an appropriate shape is formed according to the plate thickness of the beam web 2b. Apply. When the plate thickness is thin, groove processing is not necessary. When the plate thickness is thick, a labyrinth with a straight skin plate 1a is used so as to achieve complete penetration welding. The groove processing may be performed on either side or one side of the beam web 2b.

  The beam web 2b is provided with a scallop 5 for avoiding interference between the turn welding of the fillet weld portion 6 and the backing metal 50 of the steel pipe column beam flange weld joint. The bending is transmitted to the steel column 1 via the upper and lower beam flanges 2a, and the shearing force is transmitted to the steel column 1 via the beam web 2b. Fix to 1a.

  In the case of the factory welding shown in the drawing, construction is performed by forming the butt weld 7 of the steel column 1 and the steel beam 2 including the plate member 10 after welding the plate member 10 to the beam flange 2a by fillet welding. The plate-like member 10 is connected to the beam flange 2a of the steel beam 2 and the through diaphragm 3 of the steel column.

  Further, in the case of factory welding, since welding can be performed in an optimal welding posture such as downward welding or sideways welding, the plate-like member 10 is positioned below the lower beam flange 2a, and the upper beam flange 2a A vertically symmetrical structure can be obtained.

  FIG. 4 shows a case where the beam-column joint structure according to another embodiment of the present invention is manufactured by field welding, FIG. 4 (a) is a side view of the beam-column joint, and FIG. 4 (b) is FIG. FIG. 4A is a detailed view of the A part of FIG. 4A, and FIG. 4C is a view illustrating the state of attachment of the plate-like member to the beam flange as viewed from the arrow B-B of FIG. FIG.4 (d) shows the figure explaining the attachment condition of the beam web to a steel column by the cc arrow line view of Fig.4 (a). In these figures, 8 indicates a gusset plate, and the same reference numerals as those in FIG.

  When manufacturing by field welding, the gusset plate 8 is attached to the steel column 1 by welding in advance, the steel beam 2 is suspended between the steel columns 1 and 1, and the beam web 2b is attached to the gusset plate 8 with high strength bolts 9. After the temporary fixing, the butt welding 7 including the plate-like member 10 is performed, and after the completion, the high strength bolt 9 is finally tightened to join the steel column 1 and the steel beam 2.

  In general, since upward welding is not preferable for welding, in the field welding, the plate-like member 10 is positioned on the lower beam flange 2a and has the same positional relationship as the upper beam flange 2a. Thereby, the butt welding 7 can be performed downward also on the lower beam flange 2a side.

  In the above description, the description is limited to closed cross-section columns such as steel pipe columns, but the present invention can also be applied to open cross-section columns such as H-shaped steel columns. Moreover, although the case where the steel beam is attached to the steel column from only one side is shown, it goes without saying that a plurality of steel beams are attached according to the outer column, the middle column, and the inner column.

  Moreover, the column beam joint part according to the present invention is also effective when the beam flange is directly welded to the steel plate column skin plate. In this case, the groove 4 is a groove with a straight skin plate and an obliquely processed beam flange side. Of the dimensions of the plate member, the plate thickness and the length in the beam length direction are appropriately determined according to the desired beam end strength.

DESCRIPTION OF SYMBOLS 1 Steel column 1a Skin plate 2 Steel beam 2a, 2c Beam flange 2b Beam web 3 Through diaphragm 4 Groove 5 Scallop 6 Fillet weld part 7 Butt weld part 8, 12 Gusset plate 9 High-strength bolt 10 Plate-like member 10a End part 40 welding part 50 backing metal 51 end tab

Claims (2)

A beam-to-column connection structure in which beams made of steel having upper and lower flanges are welded to a steel column, wherein the steel column and the beam are joined by a steel column beam flange welded joint and a steel column beam web welded joint. Part
The steel column beam flange welded joint is a joint obtained by completely melting and welding the groove part of the beam flange and the plate-like member joined to the outside thereof and a through diaphragm of the steel column,
The steel column beam web welded joint is a welded portion where the butted portion of the steel column and the web of the beam is welded,
The beam web is provided with scallops for welding the steel column beam flange welded joint and the steel column beam web welded joint,
The plate-like member is a taper plate that linearly decreases in thickness from a thick part to a thin part, has a plate width substantially the same as the flange width of the beam, and the end on the steel column beam flange welded joint side is A column having an appropriate length on the beam side and fillet welded to the beam flange as a thick portion of a plate thickness obtained by subtracting the plate thickness of the flange of the beam from the plate thickness of the through diaphragm Beam joint structure. The plate-like member has a portion where the plate thickness decreases in a cross section excluding both ends in the plate length direction, has a plate width substantially the same as the flange width of the beam, and is on the steel column beam flange welded joint side The thickness of the end of the diaphragm is obtained by subtracting the thickness of the flange of the beam from the thickness of the diaphragm, and is fillet welded to the beam flange with an appropriate length on the beam side. The beam-column joint structure according to claim 1.

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