JP2023005950A - H-shaped steel beam for weld assembling, and column-beam joint structure - Google Patents

Abstract

To provide an H-shaped steel beam for weld assembling and a column-beam joint structure allowing plastic deformation performance and weld-construction efficiency upon production to be improved at the same time.SOLUTION: An H-shaped steel beam 1 for weld assembling is obtained by welding and joining a beam web 5 and a beam flange 3, has a scallop 9 at a boundary part between the beam web 5 and the beam flange 3 at a beam material axial direction end part which is a joint part between itself and a column 7, and has a non-welded area (a) starting from a scallop bottom 10 at a boundary between the beam flange 3 and the beam web 5, where the beam flange 3 and the beam web 5 are not welded and joined in a material axis direction.SELECTED DRAWING: Figure 1

Description

There is an application for exception to loss of novelty

TECHNICAL FIELD The present invention relates to a welded assembled H-section steel beam in which a beam web and a beam flange are welded together, and a column-to-beam connection structure using the welded assembled H-shaped steel beam.

Column-beam joints of steel structures are required to exhibit sufficient plastic deformation performance to prevent brittle fracture and collapse of steel structures against large deformation of beams during earthquakes. In other words, the shape and characteristics of the weld near the beam end are important parts for the seismic safety of the building. It can be said that artificiality is large. In addition, recently, steel materials with higher strength than SN400 and SN490 steel materials for building structures are being widely applied to beams, and the importance of production control to ensure the quality of welds is increasing.

The welded assembled H-section beam dealt with in the present invention is efficiently manufactured by combining three thick steel plates and joining the beam flange and the beam web by submerged arc welding, which is the most common manufacturing method. However, at both ends in the material axial direction, that is, at the start and end of the weld, from the viewpoint of quality and shape control of the welded part, the submerged arc welding is stopped several tens of mm short of both ends, and manual or semi-automatic welding such as gas shielded arc welding is performed. In many cases, the beam flange and beam web are welded at the end.

In addition, a notch called a scallop must be provided in the beam web at the end of the beam in order to allow the welding line between the beam flange and the column and the backing metal therefor to pass through. The beam flange and beam web are generally welded by fillet welding or partial penetration welding, and there is an unwelded portion near the center of the thickness of the beam web near the bottom of the scallop.
In order to avoid the unwelded portion from being exposed on the surface, in the gas-shielded arc welding described above, boxing welding including the scalloped bottom is often performed.

On the other hand, based on past earthquake damage and experimental research, it has been pointed out that there is a danger that cracks may develop in the thickness direction of the beam flange starting from this scallop bottom, leading to early brittle fracture (for example, Patent document 1). In addition, cracks from this scalloped bottom may grow ductile and combine with ductile cracks generated from the beginning and end of the column-to-beam flange weld, leading to fracture. This mechanism will be described later.

In any case, suppressing the generation and propagation of cracks in the thickness direction of the beam flange from the scalloped bottom leads to an improvement in seismic safety of the column-to-beam joint. From this point of view, proposals for devising the shape of the scallops to suppress crack generation (Non-Patent Document 1 and Patent Document 1) and proposals for suppressing crack growth from the scallop bottom (Patent Documents 2 and 3) ) is done.

Non-Patent Document 1 shows that the arc-shaped scallop is not a simple 1/4 circle, but a compound circle that combines small circles with a radius of about 10 mm near the boundary with the beam flange. , the cross-sectional changes of the beam flange and beam web at the scalloped bottom are moderated.
Patent document 1 also proposes a compound circular scalloped shape.
In this case, after the scalloped bottom is scalloped as described above, the scalloped portion is cut with a bar-shaped grinder or the like to form a smooth shape with respect to the beam flange.

In addition, in Patent Documents 2 and 3, it is not premised on a composite circular scallop, and the presence or absence of box welding is not clear. It is expected to have the effect of deterring the progress of

Japanese Patent Application Laid-Open No. 2020-23785 JP-A-2001-248231 JP-A-11-315581

Architectural Institute of Japan: Technical Guideline for Steel Construction - Factory Production, 6th Edition, Section 4.8 Scalloping, pp.235-253, 2018.1

In the case of Non-Patent Document 1 and Patent Document 1, it is necessary to cut the boxing weld with a rod-shaped grinder or the like to make it smooth against the beam flange, but the beam web and the boxing weld must be cut with a grinder or the like. In addition, there is a problem that the work of forming into a predetermined shape requires a great deal of processing time, and that there is a risk of damaging the beam flange, which is a healthy portion, during cutting.

Moreover, in the case of Patent Documents 2 and 3, since the beam flange is provided with the missing portion, the yield strength of the beam is inevitably lowered, and there is also the problem that processing is required.

The present invention has been made in order to solve such problems, and provides a weld assembled H-section steel beam and the weld assembled H-section steel beam that can simultaneously improve plastic deformation performance and welding efficiency during fabrication. The object is to provide a column-to-beam joint structure using

(1) The welded assembled H-section steel beam according to the present invention is formed by welding a beam web and a beam flange,
There is a scallop at the boundary between the beam web and the beam flange at the axial end of the beam material that is the joint with the column, and the scallop bottom that is the boundary between the beam flange and the beam web at the scallop is the starting point. , wherein the beam flange and the beam web have a non-welded region in which the beam flange and the beam web are not welded together in the axial direction of the material.

(2) In the above (1), the scallop bottom is characterized in that the tangent line between the scallop and the beam flange forms an angle of 90° or less with the scallop gap side.

(3) In addition, in the above (1) or (2), the column or diaphragm and the beam flange are joined by full penetration welding with a square groove, and the beam end is welded from the surface of the square groove. The distance to the scalloped bottom in the part is 10 mm or more.

(4) A column-to-beam connection structure according to the present invention is characterized in that the flange end of the welded assembled H-shaped steel beam according to any one of (1) to (3) is welded to a column. .

In the present invention, a scallop is provided at the boundary between the beam web and the beam flange at the axial end of the beam material that is the joint with the column, and the scallop bottom is the boundary between the beam flange and the beam web at the scallop. Starting from, the beam flange and the beam web have a non-welded area where the beam flange and the beam web are not welded together in the axial direction of the material, thereby eliminating the need for complicated processing and welding at the ends of the beam material in the axial direction and reducing the beam flange plate thickness It is possible to suppress the occurrence and propagation of cracks in the direction, and it is possible to realize both the improvement of processing efficiency and the improvement of deformation performance of the welded assembled H-shaped steel beam.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing of the weld assembly H-shaped steel beam which concerns on embodiment of this invention. FIG. 2 is a view taken along line AA in FIG. 1; FIG. 2 is an explanatory diagram for explaining the details of the vicinity of the slur cup shown in FIG. 1; It is explanatory drawing of the beam end part in the weld assembly H section steel beam based on a prior art example. BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing explaining the outline|summary of the test apparatus in an Example. It is explanatory drawing of the test body which concerns on an invention example (the 1). It is explanatory drawing of the test body which concerns on a prior art example. It is explanatory drawing of the test body which concerns on an invention example (the 2).

A weld assembled H-section steel beam according to one embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG.
1 and 2 are explanatory views of the welded assembled H-shaped steel beam 1 according to the present embodiment, showing a state in which the welded assembled H-shaped steel beam 1 is joined to a column 7 to form a beam-to-column joint structure. . In Figures 1 and 2, 1 is a welded assembled H-beam, 3 is a beam flange, 5 is a beam web, 7 is a column, 9 is a scallop, 10 is a scallop bottom, 11 is a flange-web weld, 13 is a back Patch 15 is the post-flange weld.
As shown in FIGS. 1 and 2, the welded assembled H-section steel beam 1 according to the present embodiment is formed by welding a beam web 5 and a beam flange 3 together.
A scallop 9 is provided at the boundary between the beam web 5 and the beam flange 3 at the axial end of the beam member, which is the joint with the column 7, and a scallop bottom 10 is provided at the boundary between the beam flange 3 and the beam web 5. As a starting point, the beam flange 3 and the beam web 5 have a non-welded region a (see the partially enlarged view of FIG. 1) where the beam flange 3 and the beam web 5 are not welded together in the material axial direction.
A detailed description will be given below.

<Pillar>
The pillar 7 is a steel pipe pillar, and the connecting portion with the beam may be either an inner diaphragm or an outer diaphragm.
In the case of the inner diaphragm, the beam ends are directly connected to the skin plate of the column 7, as shown in FIG.
In the case of an outer diaphragm, the beam ends are connected through the diaphragm.
A column-flange weld 15, which is a welded portion between the column 7 (or diaphragm 29 (see FIG. 5)) and the beam flange 3, is joined by full penetration welding using a square groove.

<Scalloped>
The scallop 9 is a notch provided at the boundary between the beam flange 3 and the beam member axial end of the beam web 5. The shape of the scallop 9 is not particularly limited. Alternatively, it may be a rectangle or the like.
However, at the scallop and beam flange boundary (scallop bottom 10), it is preferable that the angle α (see the partial enlarged view of FIG. 1) formed by the tangent line 16 between the scallop 9 and the beam flange 3 to the scallop gap side is 90° or less. .

In the conventional example, since the scallop bottom 10 is box-welded, the angle .alpha. However, in the present invention, since no rounding welding is performed, the angle α at the scallop bottom is the same as the scallop notch shape, and it is desirable to set it to 90 degrees or less so that the scallop can be easily cut. That is, by setting α to 90 degrees or less, the scalloped shape can be a simple quarter circle, triangle, rectangle, or square, facilitating the web cutting operation.

Moreover, it is preferable that the distance from the groove surface of the beam flange 3 to the scallop bottom 10 is 10 mm or more. The reason will be explained based on FIG.
In CO ₂ welding with a heat input of around 30,000 J/cm, which is often used for complete penetration welding between beam flange 3 and column 7 (or diaphragm 29), the groove surface is usually at least about 3 mm (see a in Fig. 3). ) causes penetration of the weld metal. Furthermore, there is usually a heat-affected zone 17 of about 3 mm (see b in FIG. 3) where the structure may change due to welding heat and the strength and toughness may decrease.

Also in fillet welding or partial penetration welding of the flange-web weld 11, it is considered that a heat-affected zone 18 of about 3 mm (see c in FIG. 3) similarly exists on the flange surface.
If the heat-affected zones 17 and 18 of both are overlapped, there is a concern that the toughness and strength will be further deteriorated due to repeated welding heat, and that plastic deformation will be concentrated in the heat-affected zones 17 and 18. Become.
Therefore, in order to prevent the heat affected zones 17 and 18 from overlapping, it is necessary to keep the groove surface of the beam flange 3 and the toe of the flange-web weld 11 approximately 10 mm or more apart.
Considering the effects of heat shrinkage and welding errors associated with welding, and ensuring and managing the above 10 mm or more, in the present invention, the unwelded portion a extends from the scallop bottom 10 in the material axial direction. Since it exists, it is reliable if the distance d from the groove surface of the beam flange 3 to the scallop bottom 10 is 10 mm or more.

<Non-weld area>
The unwelded region a is a region where the beam flange 3 and the beam web 5 are not welded together in the material axial direction, starting from the scallop bottom 10 that is the boundary between the beam flange 3 and the beam web 5 in the scallop 9 .
The axial length of the unwelded region a is preferably 30 mm or less. The reason why it is preferable that the same length is 30 mm or less is that if the axial length of the unwelded area a is too long, the flange may locally buckle in the unwelded area, and the bending rigidity and yield strength of the beam may be impaired. Since there is a possibility that it may be
Moreover, the axial length of the unwelded region a is preferably 10 mm or more. When a solid tab made of ceramic or the like is provided to control the shape of the terminal end of the welded portion, the size of the solid tab that is easy to handle is taken into consideration.

According to the present embodiment configured as described above, plastic deformation performance is improved. The reason for this will be described in comparison with FIG. 4 showing a conventional example. FIG. 4(a) is a side view of the beam end corresponding to the partial enlarged view of FIG. 1, and FIG. 4(b) is a plan view corresponding to FIG. are given the same reference numerals.
In the example shown in FIG. 4, as shown in Patent Document 1, the beam web 5 and the beam flange 3 are joined by submerged arc welding (submerged arc welded portion 19), and the portion of several tens of mm at the beam end is gouged. Then, the scalloped bottom 10 and the scalloped bottom 10 are welded by gas-shielded arc welding (gas-shielded arc welded portion 21).

In the example shown in FIG. 4, when stress in the strong axial direction (vertical direction in the drawing) acts on the beam, the beam web 5 and the beam flange 3 tend to separate at the scallop bottom 10, but the scallop bottom 10 is welded. Therefore, this portion is a portion where the shape changes abruptly and where a heat-affected zone exists. In addition, generally, the boxing weld tends to be welded with a relatively small heat input, and the strength of the weld metal tends to be higher than that of the base material. Furthermore, the toe of the boxing weld and the toe of the flange end weld 15 tend to come close to each other. Therefore, the point becomes a point of discontinuity in shape and strength, and as pointed out in Non-Patent Document 1, in the welded portion between the beam web 5 and the beam flange 3, starting from the scallop bottom 10, the beam flange plate thickness direction There is a risk that the crack 23 will grow in the gap and lead to premature brittle fracture. In addition, as shown in FIG. 4B, the crack 23 from the scallop bottom 10 ductilely propagates in the beam width direction and is coupled with the ductile crack 25 generated from the beginning and end of the column-beam flange weld. This may lead to premature rupture.

On the other hand, in the present embodiment, as shown in FIGS. 1 and 2, by having a non-welded region a at the axial end of the beam material, cracks occurring in the welded portion between the beam web 5 and the beam flange 3 are eliminated. The direction of 23 tends to progress in the beam axial direction rather than in the beam flange plate thickness direction. Therefore, even if a ductile crack 25 occurs from the beginning and end of the column-flange weld 11, the direction of the crack 23 is different from the crack 23 and the distance is also far (see FIG. 2), so the example shown in FIG. As in, it becomes difficult to connect to this. Therefore, unlike the conventional example shown in FIG. 4, premature breakage due to connection of the cracks 23 does not occur.
Further, in the present embodiment, the distance X between the weld toe of the beam web 5 and the beam flange 3 and the toe of the column-flange weld 15 at the end of the beam flange (see FIG. 1 enlarged view) is (a) is further away than the conventional example shown in FIG. can be expected.

In addition, even if the crack 23 at the axial end of the beam material has progressed to some extent in the axial direction of the beam material, the beam flange 3 and the beam web 5 are joined to the column 7 by welding or bolts, so that the cross-sectional shape of the H-section steel can be obtained. is retained, the flexural rigidity and strength of the beam are not immediately impaired.
In this way, by having the non-welded region a at the axial end of the beam material as in the present embodiment, the generation and propagation of cracks in the beam flange plate thickness direction at the beam flange-beam web boundary are suppressed. It is expected to improve the deformation performance of the beam.

In addition, according to the present embodiment, in the flange-web welded portion at the axial end of the beam material of the welded assembled H-section steel, which has been a problem in the conventional technology, the smoothing of the scallop bottom by the bar grinder and the conventional technology It does not require processing such as grinder processing of the beam web as seen in .
Furthermore, in the present embodiment, the beam flange 3 and the beam web 5 are not welded at the axial ends of the beam material, and since no boxing welding by CO ₂ welding is required, only submerged arc welding can be used. It is possible to complete the joint between the beam flange 3 and the beam web 5, and it can be said that the production efficiency is high.

However, the welding of the beam flange 3 and the beam web 5 may be submerged arc welding, gas shielded arc welding, or a combination thereof. For example, in order to ensure good weld quality, submerged arc welding is stopped before the scallop 9 and gouging is performed, and then welding is performed up to the vicinity of the scallop 9 (before the unwelded portion) by gas shielded arc welding. Even in this case, it can be said that the working efficiency is higher than that of the conventional example, because no round welding or grinder treatment is required.
As described above, according to the present embodiment, it is possible to suppress the occurrence and propagation of cracks in the thickness direction of the beam flange without requiring complicated processing or welding at the ends in the axial direction of the beam material. That is, it is possible to achieve both an improvement in processing efficiency and an improvement in deformation performance of the welded assembled H-section steel beam 1 .

Also, when the beam end flange-column skin plate or diaphragm 29 full penetration weld and the scallop bottom 10 are in close proximity, if there is a conventional scallop bottom welding, the weld toes of both will be close, and the shape and weld A discontinuity in strength due to heat occurs in a narrow region, and there is a concern that cracks 23 are likely to occur.
However, since the flange-web welded portion 11 is separated from the edge by 10 mm or more as in the present embodiment, the discontinuity in shape and strength described above does not occur in a narrow region, and local concentration of strain occurs in the conventional technique. mitigated by comparison.
In the case of general CO ₂ welding, the width of the heat affected zones 17 and 18 is about 3 mm. The total width of the affected parts 17 and 18 is approximately less than 10 mm. In this embodiment, since the non-weldable area a is set to 10 mm or more, the distance from the groove surface of the beam flange 3 is 20 mm, which is approximately twice the heat-affected zone of 10 mm. Overlapping of affected parts can be reliably prevented.

In order to demonstrate the effects of the present invention, a loading experiment was conducted using a column-beam frame.
The outline of the test apparatus 27 is as shown in FIG. 5, and the welded assembly H-shaped cross-section beam used for the test specimen is BH-600×200×16×25 (unit: mm). In FIG. 5, the parts corresponding to those in FIG. 1 are given the same numbers (the unit of dimension in the figure is mm). In addition, in the test apparatus 27, the welded assembly H-shaped cross-section beam is welded to the diaphragm 29 of the column 7. As shown in FIG.
A scallop 9 is provided at the weld joint between the column 7 and the beam, and its detailed specifications were used as experimental parameters.

The details of the design specifications of the test piece 31, which is an example of the invention, are as shown in FIG. ing.
On the other hand, the details of the design specifications of the test piece 33, which is a conventional example, are as shown in FIG. .
Both test pieces 31 and 33 use gas-shielded arc welding for the web-flange weld 11 in the vicinity of the scallop.
As shown in Fig. 5, the tip of the beam is repeatedly loaded by a hydraulic jack in alternating positive and negative directions. The value divided by the displacement that becomes the total plastic moment of the beam) was set to 3.0.

As a result of the experiment, in the specimen 31 of the example of the present invention, the number of repetitions (one turn is defined as 1 at a plasticity rate of ±3.0, and the half turn is 0.5) was 8.5, whereas the test specimen 33 of the prior art was 6.5. The superiority of the present invention has been demonstrated.
In addition, in the specimen 31 of the invention example, the crack 23 propagated slightly from the scallop bottom 10 in the axial direction of the beam material, and then turned in the plate thickness direction to reach the end, whereas the specimen 33 of the conventional example In this case, the crack 23 propagated in the thickness direction of the beam flange from the beginning, which was the expected result.

In addition, a specimen 31 as an invention example and a specimen 35 as an invention example in which only the length in the material axial direction in the non-welding region a is changed to 30 mm (details of design specifications are shown in FIG. 8 ), a finite element method analysis simulating monotonic loading was performed. In the analysis, a model that reproduces the experimental specimen was used for the weld penetration shape, flange, web, and strength of the weld metal.
As a result of the analysis, the magnitude of the maximum equivalent plastic strain at the aforementioned plasticity factor of 3.0 was 0.85 for the specimen 31, while it was 0.65 for the specimen 35. The magnitude of the equivalent plastic strain is considered to be correlated with the early and late occurrence of ductile cracking, and it was demonstrated that strain concentration is alleviated when the distance X between the toes increases.

a Unwelded area 1 Welded assembled H-beam 3 Beam flange 5 Beam web 7 Column 9 Scallop 10 Scallop bottom 11 Flange-web weld 13 Backing metal 15 Column-flange weld 16 Tangent 17, 18 Heat affected zone 19 Submerge Arc Welded Part 21 Gas Shielded Arc Welded Part 23 Crack 25 Ductile Crack 27 Test Apparatus 29 Diaphragm 31 Specimen (Invention Example)
33 Specimen (conventional example)
35 Specimen (Invention Example)

Claims (4)

A weld assembled H-shaped steel beam in which a beam web and a beam flange are welded together,
having a scallop at the boundary between the beam web and the beam flange at the axial end of the beam material that is the joint with the column;
Welded assembly H characterized by having a non-welded region where the beam flange and the beam web are not welded together in the material axial direction, starting from the scallop bottom that is the boundary between the beam flange and the beam web in the scallop. Shaped steel beam. 2. The welded assembled H-section steel beam according to claim 1, wherein at the scallop bottom, an angle formed by a tangent line between the scallop and the beam flange toward the scallop gap is 90 degrees or less. The column or diaphragm and the beam flange are joined by full penetration welding with a square groove, and the distance from the surface of the square groove to the scalloped bottom of the beam end is 10 mm or more. Item 3. The welded assembled H-section steel beam according to item 1 or 2. A column-to-beam joint structure, characterized in that the flange end of the weld assembled H-section steel beam according to any one of claims 1 to 3 is welded to a column.

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