JP4734840B2 - Beam-column joint - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint having an inner diaphragm type steel pipe and an H-shaped steel, and particularly to a building structure requiring an earthquake resistance in a column-beam joint having an inner diaphragm type steel pipe column and an H-shaped steel beam. It relates to a suitable one.

  In some cases, the joints between steel columns and beam flanges in buildings and other structures are broken without sufficient deformation during earthquakes, and the earthquake resistance of buildings and other structures may be impaired.

As a cause of this, although the bending moment becomes maximum at the time of an earthquake at the joint, the toughness drop due to welding and welding defects occur, and in the case of the two-inner diaphragm type, the electroslag that joins the diaphragm to the inside of the column It has been pointed out that a notch-shaped gap is generated in the weld and a crack starting from the gap occurs.

  FIG. 7 is a partial perspective view for explaining a part of the internal structure of the beam-column joint using the inner-diaphragm type steel pipe column. In the column 100 of the beam-column joint 700, the beam flange 200 joint and The inner diaphragm 400 is attached to the position.

  FIG. 8 is an enlarged view of the mounting portion of the inner diaphragm 400. Four rounds of the diaphragm 400 are welded to the inner side of the column skin plate 100 by an electroslag welding method, and the figure shows the welded portion. When welding column members of high-rise buildings, the welding heat input is 500 to 1500 kJ / cm, and the weld heat affected zone outside the weld metal 600 reaches a depth of 20 to 100 mm from the surface of the column skin plate 100. The diaphragm 400 has a welding heat affected zone of about 25 to 50 mm.

  For this reason, the column skin plate 100 is bent and deformed by heat shrinkage after welding, and voids a1 and a2 are generated in the portion where the column skin plate 100 and the backing metal 500 for electroslag welding contact. When a bending moment due to a material axial stress from the beam flange 200 and the beam web 300 acts on the inner diaphragm 400 during an earthquake, the gaps a1 and a2 act as notches, and the column beam joint is broken. A state is shown in which the tip of the gap a1 is located at a distance l1 from the position where the diaphragm 400 and the backing metal 500 where the bending moment is greatest.

  Patent Document 1 relates to a method for manufacturing an electroslag welded joint having excellent fracture resistance. After welding, a groove is provided in the part so that a gap does not occur in the part where the backing metal and the column skin plate are in contact with each other due to thermal contraction. It is described that the two are welded together.

According to the invention described in Patent Document 1, since the backing metal and the column skin plate are welded, even if the inner diaphragm is joined to the column skin plate by electroslag welding, there is no gap between the two after welding. It is possible to obtain a column beam joint with excellent earthquake resistance.
JP-A-8-155661

  However, the electroslag welding method described in Patent Document 1 requires a groove processing of the backing metal and a step of welding the backing metal and the column skin plate. In addition, the groove must be assembled in the narrow interior of the pillar, and the burden on the operator is great. Furthermore, if a notch-like defect such as a cold crack occurs in the welded portion, the earthquake resistance is not improved.

  Therefore, the present invention provides a column-to-column connection that provides excellent seismic resistance even when a notch-shaped gap (hereinafter referred to as a notch) is generated in an electroslag welded portion for attaching a diaphragm to a column in an internal diaphragm type steel column. The purpose is to provide a department.

The object of the present invention can be achieved by the following means.
1. This is a joint that joins the inner diaphragm type steel pipe and the H-shaped steel, and the groove section of electroslag welding that attaches the inner diaphragm to the steel pipe skin plate using the backing metal is the same as the inner diaphragm and backing metal . In the meantime, the spacer plate is provided between the backing metal on the web side of the H-shaped steel and the inner diaphragm, and the length of the side along the steel pipe skin plate is longer than the thickness of the inner diaphragm, Furthermore, the steel pipe skin plate on the groove cross-sectional side of the electroslag welding has a width of the inner dimension of the backing metal that holds the inner diaphragm from both sides and 1/2 to 1/3 of the plate thickness of the inner diaphragm. A junction having a groove having a depth.
2. A joint that joins an inner diaphragm type steel pipe column and an H-shaped steel beam, and the groove section of electroslag welding that attaches the inner diaphragm to the steel pipe skin plate using a backing metal is the inner diaphragm. A spacer plate is provided between the backing plate which is at least the web side of the beam and the inner diaphragm between the inner plate and the backing plate, and a rectangle whose length along at least the steel pipe skin plate is longer than the plate thickness of the inner diaphragm In addition, the steel pipe skin plate, which is the groove cross-sectional side of the electroslag welding, has a width of the inner dimension of the backing metal that sandwiches the inner diaphragm from both sides and 1/2 to 1 of the plate thickness of the inner diaphragm. A beam-column joint characterized by having a groove with a depth of / 3.

  According to the present invention, the shape of the electroslag weld metal that attaches the diaphragm to the column becomes a flat oval shape along the column skin plate.

  For this reason, the notch tip formed parallel to the column skin plate between the column skin plate and the backing metal is separated from the joining position between the column skin plate and the beam flange where the bending stress is maximized. The stress value acting to open the aperture is reduced.

  2 In addition, since the acting direction of stress is along the column skin plate, the force for opening the notch tip is reduced, and combined with the effect 1, the occurrence of breakage from the notch tip is suppressed.

  3 In particular, a great effect can be obtained at the notch on the beam web side in which a bending moment is generated in the column skin plate by a material axial stress.

  According to the present invention, in electroslag welding in which an inner diaphragm is attached to a column, at least a groove width along the column skin plate is longer than the plate thickness of the inner diaphragm, and a flat weld metal is obtained. It is characterized by. In the following description, the column will be described as a square steel pipe and the beam as an H-shaped steel.

  FIG. 1 is a schematic cross-sectional view illustrating the structure of a column beam joint according to an embodiment of the present invention. In the figure, 1 is a column skin plate, 2 is a beam flange attached to the column skin plate 1, and 3 is a beam. Web, 4 is a diaphragm, 5 is a backing metal used for electroslag welding, 6 is an electroslag weld metal, 7 is a spacer sandwiched between the diaphragm 4 and the backing metal, 8 is a scallop, 9 is a beam flange 2 and a column skin. The joint portion 10 of the plate 1 is a force flow indicating the stress acting on the diaphragm 4 from the beam flange 2, 11 is the axial stress acting on the column skin plate 1 from the beam web 3, and 12 is the groove portion. The figure shows a state after welding, and notches a1 and a2 are generated between the backing metal 5 and the column skin plate 1.

  In the column beam joint according to the present invention, a spacer 7 is sandwiched between the backing metal 5 and the diaphragm 4 at the groove portion of electroslag welding for joining the diaphragm 4 and the column skin plate 1, and the groove portion 12 is formed. A rectangular shape along the column skin plate 1 is used.

  The stress acting on the tip of the notch a1 decreases as the plate thickness of the spacer 7 is increased and the distance l2 between the tip of the notch a1 and the diaphragm 4 is increased. The plate thickness of the spacer is preferably 2 mm or more and 10% or less of the plate thickness of the diaphragm 4, more preferably 5 mm or more and 5% or less of the plate thickness of the diaphragm 4.

  If it is less than 2 mm, the stress acting on the tip of the notch a1 is not sufficiently reduced, and it is difficult to assemble the groove. Therefore, if it is 2 mm or more, the contact area between the column skin plate 1 and the weld metal 6 increases. The stress acting on the tip of the notch a1 can be reduced by about 10%, which is preferable.

  If it exceeds 10% of the plate thickness of the diaphragm 4, the amount of deposited metal increases by 20% or more, which increases welding heat input and welding material costs, so it is made 10% or less, and more preferably 5% or less of the plate thickness.

  The position of the spacer 7 is not particularly limited. Although it may be arranged on both sides of the diaphragm 4 and between the backing metal 5, when arranged only on one side, it is preferably arranged on the beam web 3 side.

  That is, the tensile stress from the beam flange 2 mainly flows to the diaphragm 4 as shown as the force flow 10, but the material axial stress 11 from the beam web 3 generates a bending moment in the column skin plate 1.

  Since the bending moment becomes larger as the scallop 8 (beam flange 2) is closer and acts to open the notch a1, when the spacer 7 is arranged on the beam web 3 side, the distance l2 between the tip of the notch a1 and the beam flange 2 is set. Is preferable and the bending moment is reduced.

  Although FIG. 1 shows a case where the groove portion 12 is rectangular, the groove portion 12 may be square. However, even in the case of a square, the length of the side along the pillar skin plate in the groove portion 12 is longer than the plate thickness of the diaphragm 4.

  FIG. 2 shows a column beam joint in which spacers 7 are arranged only on the beam web 3 side. Compared with the case where the spacers 7 are arranged on both sides of the diaphragm 4, the amount of deposited metal can be reduced, so that the welding heat input can be reduced and deterioration of the toughness of the heat affected zone can be suppressed. Moreover, a small amount of welding material is sufficient, and the construction cost can be reduced.

  FIG. 3 shows another embodiment of the present invention, and shows a case where a notch portion having a depth corresponding to the thickness of the spacer 7 is provided in the backing metal 5a in order to make the shape of the groove portion rectangular. Although the figure shows a case where notches are provided in the backing metal 5a on both sides of the diaphragm 4, it may be processed only on the backing web 5a on the beam web side where the material axial stress mainly acts from the beam web.

  FIG. 4 shows another embodiment of the present invention, and further shows a case where a groove 1a having a depth d is provided in the column skin plate 1 in order to reduce the stress acting on the tip of the notch.

  9A and 9B are diagrams for explaining the effect of providing the groove 1a. FIG. 9A shows a conventional example, and FIG. 9B shows an example of the present invention. Since the weld metal part 6 of electroslag welding approaches the beam flange 2 by the depth of the groove 1a, the main stress 16 flows in parallel to the notches a1 and a2, and the occurrence of fracture starting from the notch is caused. It becomes possible to suppress.

  The dimension of the groove 1a is such that the depth d is 10 mm or more, preferably 1/2 to 1/3 of the diaphragm thickness, and the width is left and right in order to prevent defects such as electroslag welding burnout and inadequate penetration. The inner size of the backing metal is about the same size.

  When machining the notches and grooves shown in FIGS. 3 and 4 described above, it is preferable to prevent the welding defect by attaching an R to the corner. In addition, this invention is not limited to a column beam junction, It can apply to the junction which manufactures the T-shaped member which consists of a horizontal member and a member perpendicular | vertical to this horizontal member using electroslag welding.

  Hereinafter, the effect of the present invention will be described using examples.

  The inner-diaphragm column beam-to-column joints were manufactured under various groove processing conditions, and the forcible displacement was applied to the end of the beam in the event of an earthquake, and the fracture condition was observed.

The column is made of 590 N / mm grade ² steel, and a 40 mm thick diaphragm is welded to a skin plate with a thickness of 60 mm by electroslag welding (welding material: 640 N / mm grade ² solid wire diameter 1.6 mm). It was.

The columns and beams were welded with a semi-automatic CO ₂ gas shield (welding material: 540 N / mm class ² , diameter 1.4 mm).

  The column had a cross section of 600 mm × 600 mm and a length of 3.5 m (distance between fulcrums), and the beam was H-900 × 300 × 18 × 32 and a length of 4 m (loading point distance).

  Example 1 of the present invention is a case where the groove portion shown in FIG. 1 is used and a groove portion obtained by cutting a groove is used for the pillar skin plate. In the groove portion, a spacer plate (plate thickness 12 mm, width 20mm) is sandwiched between the diaphragm and the backing metal on the web side of the beam, and a U-shaped groove with a depth of 20mm is cut into the column skin plate with the same width as the inner dimension of the backing metal. It was processed into a rectangular shape with a groove cross-sectional dimension of 52 mm on the column skin plate side and 40 mm on the diaphragm side. The welding heat input was 1000 kJ / cm.

  In Invention Example 2, a rectangular groove having the same dimensions as in Invention Example 1 was manufactured using a steel material of 50 mm × 50 mm square instead of the spacer plate, and electroslag welding was performed.

  Example 3 of the present invention is a rectangular groove having the same dimensions as Example 1 of the present invention, but the U-shaped groove of the pillar skin plate is not cut in Example 1 of the present invention, and the backing metal is made 40 mm × 60 mm. Then, electroslag welding was performed.

  In Comparative Example 1, electroslag welding was performed without cutting a U-shaped groove on the column skin plate in Example 1 of the present invention, and with a groove cross-sectional dimension of 40 mm × 40 mm.

  About the electroslag welding part of this invention example 1-3 and the comparative example 1, when the macro cross section was observed after welding, the penetration depth was 1.2-1.6 mm.

  FIG. 5 shows the test method. The forced displacement assumed at the time of an earthquake was made to act on the edge part of the beam 13 of the column-beam junction part of the column 14 and the beam 13 which were manufactured by one of the methods mentioned above. Both ends of the column 14 were fixed with pins 15.

  For the forced displacement, 2δp, 3δp, 4δp, 5δp, 6δp, 7δp, and 8δp were loaded twice each until the proof stress decreased based on the elastic deformation amount δp when the beam end total plastic moment was applied.

  FIG. 6 shows the test results. The test results were dimensionless maximum deformation (maximum displacement at the beam end / elastic deformation amount δp at the time of the total plastic moment acting on the beam end). In Examples 1-3 of the present invention, the maximum deformation was determined by the fracture of the beam. The loading of 4δp was completed twice, and the load decreased during the loading of 5δp.

  After the test, when the electroslag welded portion of the comparative example was cut, it was observed that a crack originated from the notch portion on the beam web side formed by the backing metal and the column skin plate.

The figure which shows the junction part structure which concerns on one Embodiment of this invention. The figure which shows the junction part structure which concerns on one Embodiment of this invention. The figure which shows the junction part structure which concerns on other embodiment of this invention. The figure which shows the junction part structure which concerns on other embodiment of this invention. The figure explaining the test method of an Example. Example. Conventional example. Conventional example. It is a figure explaining the flow of the main stress in a junction part, (a) shows a prior art example, (b) shows the example of this invention.

Explanation of symbols

1 Pillar skin plate
1a groove
2 Beam flange
3 Beam web
4 Diaphragm
5, 5a, 5b Back money
6 Electroslag weld metal
7 Spacer plate
8 Scallop
9 joints
10 Power flow
11 Beam axial stress of beam web
12 Groove
13 Beam (test body)
14 columns (test body)
15 pin
16 principal stress
a1, a2 Notch-shaped gap
100 pillars
200 beams
400 inner diaphragm
500 Back Money
600 weld metal
700 Beam-column joint

Claims (2)

This is a joint that joins the inner diaphragm type steel pipe and the H-shaped steel, and the groove section of electroslag welding that attaches the inner diaphragm to the steel pipe skin plate using the backing metal is the same as the inner diaphragm and backing metal . In the meantime, the spacer plate is provided between the backing metal on the web side of the H-shaped steel and the inner diaphragm, and the length of the side along the steel pipe skin plate is longer than the thickness of the inner diaphragm, Furthermore, the steel pipe skin plate on the groove cross-sectional side of the electroslag welding has a width of the inner dimension of the backing metal that holds the inner diaphragm from both sides and 1/2 to 1/3 of the plate thickness of the inner diaphragm. A junction having a groove having a depth. It is a joint that joins the inner diaphragm type steel pipe column and the H-shaped steel beam, and the groove section of electroslag welding that attaches the inner diaphragm to the steel pipe skin plate using the backing metal is the inner diaphragm and the back A spacer plate is provided between the backing metal on the web side of the beam and the inner diaphragm, and the length of the side along the steel pipe skin plate is longer than the thickness of the inner diaphragm. Furthermore, the steel pipe skin plate on the groove cross-sectional side of the electroslag welding has a width of the inner dimension of the backing metal that holds the inner diaphragm from both sides and 1/2 to 1/3 of the thickness of the inner diaphragm. A beam-column joint having a groove having a depth of 5 mm.

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