JP7009141B2 - Column-beam joint structure - Google Patents

Description

The present invention relates to a column-beam joint structure in which a square steel pipe column and a steel beam are joined to a steel column core arranged at a joint between a square steel pipe column and a steel beam.

A through-diaphragm type or an inner diaphragm type is adopted for a column-beam joint in a steel-framed building in which a square steel pipe is applied as a steel column and H-shaped steel is applied as a steel beam. The through-beam type column-beam joint structure has a structure in which a through-diaphragm is welded and fixed so as to project to the outside of the column core at a position corresponding to the upper and lower flanges of the steel beam in a column core made of a square steel pipe. A flange of a steel beam made of H-shaped steel is welded to the through diaphragm overhanging to the outside, and upper and lower square steel pipe columns are welded to the upper and lower through diaphragms. When the beam formation of the left and right steel beams is different, in addition to the upper and lower through diaphragms, the inner diaphragm is welded and joined in the column core at a position corresponding to the flange of the steel beam having a low beam formation, for example.

However, in these beam-column joints of the through-diaphragm type and the inner diaphragm type, the man-hours for manufacturing the beam-column joints tend to increase, and the welding length tends to be long, so that the manufacturing is generally complicated. There is a problem that it takes time to manufacture and the manufacturing cost tends to be high.

Therefore, a column-beam joining hardware for joining columns and beams of a so-called non-diaphragm type building, which omits the diaphragm, has been proposed. More specifically, at all four locations of the internal corners of the square cross-section pipe having substantially the same outer diameter as the outer diameter of the pillar of the square cross-section pipe to be joined and having a plate thickness equal to or larger than the plate thickness of the pillar. , A column-beam joint metal fitting in which a thick portion formed over a longer range than the beam formation of the beam to be joined is integrally cast and molded (see, for example, Patent Document 1).

Japanese Patent No. 4337962

However, since the beam-column joint metal fitting described in Patent Document 1 is integrally cast and molded from cast steel, ductile cast iron, etc., the thickness and height of the beam-column joint metal fitting, and the overall dimensions and shape are different. It is necessary to prepare a mold according to the shape and size of each, and it is inevitable that the mold manufacturing cost will increase when manufacturing the column-beam joint metal fittings of various shapes and dimensions, and as a result, the column-beam joint metal fittings. The manufacturing cost is high.

The present invention has been made in view of the above problems, and a steel column core that can meet the requirements of various shapes and dimensions is applied as the manufacturing cost is as low as possible, and the structure is as simple as possible. It is an object of the present invention to provide a beam-column joint structure having high rigidity.

In order to achieve the above object, one aspect of the steel column core according to the present invention is a non-diaphragm type steel column core disposed at a joint portion between a square steel pipe column and a steel beam.
In the steel column core, four steel plates are joined to each other via a welded portion, and the cross-sectional shape orthogonal to the stretching direction is rectangular.
It is characterized in that the thickness of the steel plate is thicker than the thickness of the square steel pipe column.

According to this aspect, since four steel plates are joined to each other through welds to form a steel column core forming a panel zone, it is easy to manufacture and has various shapes and dimensions. By welding a steel plate according to the requirement, a steel column core having various shapes and dimensional variations can be obtained without increasing the manufacturing cost. Further, since the thickness of the steel plate is thicker than the thickness of the square steel pipe column, the axial force and bending from the square steel pipe column can be effectively transmitted to the high-rigidity steel column core.

Further, another aspect of the steel column core according to the present invention is characterized in that the formation of the steel column core is higher than that of the steel beam.
According to this aspect, the formation of the steel column core is higher than that of the steel beam, that is, there is a predetermined extra length between the upper and lower ends of the steel column core and the steel beam. The joint between the column core made of steel and the steel beam can be a rigid joint. Further, when a seismic retrofit brace (or a buckling restraint brace) is present in the steel frame frame, the seismic retrofit brace can be connected to the extra length portion. If there is no extra length, it may be necessary to join seismic retrofitting braces to, for example, square steel pipe columns, and take reinforcement measures at the joints of the square steel pipe columns.

Further, another aspect of the steel column core according to the present invention is characterized in that the welded portion is a submerged arc welded portion.
According to this aspect, since the welded portion is formed by submerged arc welding even in arc welding, a large diameter wire is continuously arranged at the welded portion and a large current is passed to form the welded portion. Therefore, it is possible to form a welded portion having extremely high manufacturing efficiency and excellent quality.

Further, one aspect of the column-beam joint structure according to the present invention is a column-beam joint structure in which a square steel pipe column and a steel beam are joined to a non-diaphragm type steel column core.
In the steel column core, four steel plates are joined to each other via a welded portion, and the cross-sectional shape orthogonal to the stretching direction is rectangular.
It is characterized in that the thickness of the steel plate is thicker than the thickness of the square steel pipe column.

According to this aspect, since the thickness of the steel plate is thicker than the thickness of the square steel pipe column, it is possible to form a column-beam joint structure having high rigidity while being a non-diaphragm type.

Further, another aspect of the beam-column joint structure according to the present invention is characterized in that the formation of the steel column core is higher than that of the steel-framed beam.
According to this aspect, since the formation of the steel column core is higher than that of the steel beam, the joint portion between the steel column core and the steel beam can be rigidly joined.

Further, another aspect of the beam-column joint structure according to the present invention is characterized in that the square steel pipe column has four corners having curvatures, and the four corners also exist within the thickness of the steel column core. do.
According to this aspect, even when a square steel pipe column having curved corners is applied, the axial force from the square steel pipe column can be obtained by allowing the entire cross section of the square steel pipe column to exist within the cross section (thickness) of the steel column core. Bending can be effectively transmitted to a highly rigid steel column core.

Further, in another aspect of the beam-column joint structure according to the present invention, the plurality of steel-framed beams joined to the steel column core are stepped beams having different beam formations, which is higher than that of steel-framed beams having relatively high beam formation. Is also characterized by high growth of the steel column core.
According to this aspect, when a plurality of stepped beams having different beam formations are joined to the steel column core, the formation of the steel column core is higher than that of the steel-framed beam having the highest beam formation. The joint between the steel column core and all steel beams with different beam formation can be rigidly joined.

Further, in another aspect of the beam-column joint structure according to the present invention, the thickness tp of the steel plate satisfies all of the following three conditional equations (A), (B), and (C) based on the yield line theory. It is characterized by being thick.

本態様によれば、降伏線理論に基づいた条件式を満たすように鋼製コラムコアを形成する鋼製プレートの厚みが設定されていることにより、鋼製コラムコアがノンダイアフラム形式を適用しながらも、十分な構造耐力を有する柱梁接合部構造を提供することができる。

According to this aspect, the thickness of the steel plate forming the steel column core is set so as to satisfy the conditional expression based on the yield line theory, so that the steel column core applies the non-diaphragm type. Also, it is possible to provide a beam-column joint structure having sufficient structural strength.

Further, in another aspect of the beam-column joint structure according to the present invention, the formation of the steel column core is higher than that of the steel column core, and the upper end and / or the lower end of the steel column core and the steel beam are formed. It is characterized in that there is a surplus portion between the upper end and / or the lower end, and the surplus length lp of the surplus portion has a length satisfying the following conditional expression (D).

本態様によれば、降伏線理論に基づいた条件式を満たすように余長部の余長ｌｐが設定されていることにより、鋼製コラムコアがノンダイアフラム形式を適用しながらも、鋼製コラムコアと鉄骨梁の接合部を剛接合とすることができる。

According to this aspect, the extra length lp of the extra length portion is set so as to satisfy the conditional expression based on the yield line theory, so that the steel column core applies the non-diaphragm type, but the steel column. The joint between the core and the steel beam can be a rigid joint.

As can be understood from the above description, according to the beam -column joint structure of the present invention, a steel column core capable of meeting various shape and dimension requirements at the lowest possible manufacturing cost is applied . It is possible to provide a beam-column joint structure whose structure is as simple as possible and which is highly rigid.

It is a perspective view of an example of a steel column core which concerns on embodiment. It is an arrow view of FIG. 1 in the II direction. It is a perspective view of an example of the column-beam joint structure which concerns on embodiment. It is an arrow view of FIG. 3 in the IV direction. FIG. 3 is a sectional view taken along line VV of FIG. It is a figure explaining the out-of-plane bending yield mechanism.

Hereinafter, the steel column core and the beam-column joint structure according to the embodiment will be described with reference to the attached drawings.

[Embodiment]
<Steel column core>
First, an example of the steel column core according to the embodiment will be described with reference to FIGS. 1 and 2. Here, FIG. 1 is a perspective view of an example of a steel column core, and FIG. 2 is an arrow view in the II direction of FIG. The steel column core 10 is formed of a total of four steel plates 1 and 2, two each having a different width. Grooves 2a, which are tapered and have an inclination angle of about 30 to 50 degrees, are formed at both ends of the steel plate 2 having a relatively short width in the extending direction of the steel plate 2. A long-width steel plate 1 and a short-width steel plate 2 are arranged as shown in FIG. 1, and a backing metal 4 is arranged inside the four corners along the short-width steel plate 2. In this state, the welded portion 3 is formed in the groove 2a, and the hollow and square columnar steel column core 10 is formed.

As shown in FIG. 2, the planar shape of the steel column core 10 is a square having a side length of Dp. However, depending on the cross-sectional shape of the upper pillar and the lower pillar joined to the steel column core 10, a steel column core having a shape other than a square shape, for example, a rectangular plan view shape may be used. The thickness tp of the steel plates 1 and 2 is thicker than that of the column core provided with a normal diaphragm. This thickness tp will be described in detail below.

The welded portion 3 can be formed by other arc welding methods such as arc spot, arc stud, gas shield arc, plasma welding, electro slag welding, electron beam welding, laser beam welding, and various other welding methods. It is a submerged arc welded portion 3 formed by submerged arc welding, which is most excellent in both manufacturing efficiency and quality. In the submerged arc welding method, granular flux is sprayed along the welding line, solid wire is continuously supplied into it, and an arc is generated between the base metal and the wire while being covered with flux. It is a method of melting and connecting both. According to the submerged arc welding method, since a large current is passed through a large-diameter wire, the efficiency is about ten times higher than that of normal manual welding. In addition, it generally penetrates deeply, the welding quality is stable, the bead appearance is uniform and beautiful, and a welded portion with high joint reliability can be formed. For example, it is possible to manufacture a steel column core 10 having a length about ten times as long as that of the steel column core 10 shown in FIG. 1 and to continuously manufacture the steel column core 10 shown in FIG. According to the method, the steel column core 10 can be manufactured more efficiently.

The steel column core 10 of a hollow square prism having a square view in a plan view, in which four thick steel plates 1 and 2 are joined to each other at a submerged arc weld 3, is of a non-diaphragm type. However, it is a column core with extremely high rigidity and good manufacturing efficiency. Further, by adjusting the width, length and thickness of the steel plates 1 and 2 as desired, column cores having various shapes and dimensions can be obtained.

Further, since the steel column core 10 does not have a diaphragm inside, for example, when concrete is filled in the steel column core 10 to further increase the rigidity, it is easy to fill the concrete. Can be done.

Although not shown, four steel plates of one type are used, and each steel plate has a groove only at one end, and the groove is brought into contact with the side surface of the adjacent steel plate for welding. By joining through the portions, a steel column core having the same shape and dimensions as the steel column core 10 shown in FIG. 1 can be obtained.

<Beam joint structure>
Next, the column-beam joint structure according to the embodiment will be described with reference to FIGS. 3 to 5. Here, FIG. 3 is a perspective view of an example of the column-beam joint structure, FIGS. 4 and 5 are arrow views in the IV direction of FIG. 3, and are VV cross-sectional views of FIG. In the column-beam joint structure 100, steel beams 30 and 40 made of H-shaped steel are joined to the steel plates 1 and 2 of the steel column core 10 forming the panel zone, and the upper and lower parts of the steel column core 10 are joined. Square steel pipe columns 20 having the same cross-sectional shape, which are upper columns and lower columns, are joined to the ends, respectively. Although not shown, the webs and flanges of the steel beams 30 and 40 are connected to the steel plates 1 and 2 by complete penetration welding. Further, the square steel pipe column 20 is also connected to the end faces of the steel plates 1 and 2 by complete penetration welding. Since the column-beam joint structure 100 is a non-diaphragm type structure, it is possible to eliminate the scallops provided above and below the end of the web of the steel frame beam, which is required when the beam has a diaphragm.

As shown in FIG. 4, in relation to the plane dimensions of both the steel column core 10 and the square steel pipe column 20, the cross section of the square steel pipe column 20 is completely accommodated within the cross section of the steel column core 10. The overall dimensions of both, the plate thickness tp of the steel plates 1 and 2, and the thickness ct of the square steel pipe column 20 are set. More specifically, the plate thickness tp of the steel plates 1 and 2 is a thickness that completely accommodates the cross section of the square steel pipe column 20, and at the same time, as described in detail below, the steel column core 10 has a yield line. The thickness is sufficient to satisfy the ultimate strength using the theory.

As shown in FIG. 4, the square steel pipe column 20 is a steel pipe column having a radius of curvature r at four corners and having a side length of Dp in a square view in a plan view. It is assumed that the plate thickness tp of the steel plates 1 and 2 is larger than the thickness ct of the square steel pipe column 20, but the entire cross section of the square steel pipe column 20 is completely accommodated in the cross section of the steel column core 10. It is necessary to specify the condition that the curved portions at the four corners are completely accommodated in the cross section of the steel column core 10.

The square steel pipe column 20 includes BCR (Box Column Roll cold roll formed square steel pipe for building structure, registered trademark) and BCP (Box Column Press cold pressed square steel pipe for building structure), which are cold-formed square steel pipes for building structures. Steel pipe, registered trademark) is used. These are square steel pipes manufactured by the Japan Iron and Steel Federation, which are based on SN materials (steel materials for building structures).

In FIG. 4, in order for the R portion of the square steel pipe column 20 to be accommodated in the cross section of the steel column core 10 at the corners of the four corners, the following equation (1) must be satisfied. It is necessary to satisfy the following equation (2) using the variables r and tc.

従って、ＢＣＲを適用する場合は以下の式（３）を満たすように、また、ＢＣＰを適用する場合は以下の式（４）を満たすように鋼製プレート１，２の板厚ｔｐ及び角形鋼管柱２０の厚みｔｃが設定される。

Therefore, when BCR is applied, the following formula (3) is satisfied, and when BCP is applied, the following formula (4) is satisfied. The thickness tc of the pillar 20 is set.

このように、ＢＣＲとＢＣＰでｔｐの数値範囲は相違する。

In this way, the numerical range of tp differs between BCR and BCP.

When the length of one side of the steel column core 10 is Dp and the widths of the steel beams 20 and 30 are B, the following formula (5) must be satisfied, so that the thickness ct of the square steel pipe column 20 The upper limit of is specified by the following equation (6).

このように、角形鋼管柱２０の厚みｔｃの上限値は、鋼製コラムコア１０の平面寸法と鉄骨梁２０，３０の幅寸法で変化する。

As described above, the upper limit of the thickness tc of the square steel pipe column 20 changes depending on the plane dimension of the steel column core 10 and the width dimension of the steel frame beams 20 and 30.

On the other hand, when STKR400 or STKR490, which are JIS products based on JIS G 3466 (square steel pipe for general structure), are used as the square steel pipe column 20, r is 3.0 ct or less as in the case of BCR. The plate thickness tp of the steel plates 1 and 2 and the thickness ct of the square steel pipe column 20 are set by the formula (3).

Since the entire cross section of the square steel pipe column 20 having R portions at the four corners is completely housed in the cross section of the steel column core 10, axial force, bending, etc. from the square steel pipe column 20 can be achieved. Can be effectively transmitted to the steel column core 10.

As shown in FIG. 5, the column-beam joint structure 100 has two types of stepped beams and steel-framed beams 30 and 40 having different beam formations. In the illustrated example, the steel beam 40 of the relatively high beam H3 is arranged on the left side of the steel column core 10, and the steel beam 30 of the relatively low beam H2 is arranged on the right side. The height H1 of the steel column core 10 is set higher than that of the beams H2 and H3. The steel beam 40 is attached to the center of the height of the steel column core 10, and the illustrated example has an extra length portion 50 having the same extra length lp at the top and bottom. On the other hand, the steel frame beam 30 is provided with an extra length portion 50 having an extra length lp above, and an extra length portion 60 having a long extra length lp'below the steel frame beam 30. The steel beam 40 may be attached to a position other than the height center position of the steel column core 10, and therefore the upper and lower extra lengths may have different extra lengths.

As described above, when there are extra lengths lp and lp'between the steel column core 10 and the steel beam 30 and 40, these lp and lp'are described in detail below. By satisfying the above conditions, the joint portion between the steel column core 10 and the steel frame beams 30 and 40 can be rigidly joined. Further, the presence of the extra lengths lp and lp'makes it possible to make the thickness of the steel column core 10 relatively thinner than in the case where there is no extra length.

Further, although not shown, when a seismic retrofitting brace (buckling restraint brace) is present in the steel frame, the seismic retrofitting brace can be connected to the extra length portions 50 and 60, so that the extra length portion 50 can be connected. If 60 is not present, it is possible to eliminate the need for measures such as taking reinforcement measures for the square steel column 20 while connecting the seismic retrofit brace to the square steel column 20.

The column-beam joint structure having the steel column core 10 as the panel zone may be a structure having a plurality of steel-framed beams having the same step beam and no step beam, or a square shape of the upper column and the lower column. Assuming that both the steel pipe columns are housed inside the steel column core 10 in the entire cross section, the steel pipe columns may have different dimensions from each other.

<How to set the plate thickness of the steel column core based on the yield line theory>
Regarding the method of setting the plate thickness of the steel column core 10, the first method can be set by the above-mentioned methods (3) and (4). However, in reality, since the non-diaphragm type is applied, it is important to set the plate thickness of the steel column core by the yield strength between the steel column core and the joint of the steel beam. be. More specifically, a plate thickness that satisfies all three conditions: the condition 1 is to satisfy the yield strength condition, the condition 2 is to satisfy the total plastic strength condition, and the condition 3 is to satisfy the maximum strength condition. The plate thickness shall be larger than the calculated plate thickness. In determining these three conditions, a calculation based on the yield line theory is performed. Here, FIG. 6 is a view for explaining the out-of-plane bending yield mechanism, FIG. 6 (a) is a front view of the steel column core seen from the steel beam side, and FIG. 6 (b) is made of steel. It is a top view of the column core seen from above, and FIG. 6 (c) is a side view of the steel column core seen from the side. Table 1 below describes the symbols in FIG. 6 and the symbols in the formulas shown below.

図６と表１を参照しながら、上記する各条件を満たす鋼製コラムコアの板厚を検証する。

With reference to FIGS. 6 and 1, the plate thickness of the steel column core satisfying each of the above conditions is verified.

(Condition 1: Yield strength condition)
Since the yield strength condition needs to satisfy the following equation (7), the conditional equation of the equation (8) can be obtained by specifically expressing the right side and the left side of the equation (7).

式（８）を満たすｔｐの範囲が、降伏耐力の条件から規定されるｔｐの範囲となる。

The range of tp satisfying the equation (8) is the range of tp defined by the condition of yield strength.

(Condition 2: Condition of total plastic strength)
Since the condition of total plastic proof stress needs to satisfy the following equation (9), the conditional equation of equation (10) can be obtained by specifically expressing the right side and the left side of equation (9).

式（１０）を満たすｔｐの範囲が、全塑性耐力の条件から規定されるｔｐの範囲となる。

The range of tp satisfying the formula (10) is the range of tp defined from the condition of total plastic strength.

(Condition 3: Maximum proof stress condition)
Since the condition of the maximum proof stress needs to satisfy the following equation (11), the conditional equation of the equation (12) can be obtained by specifically expressing the right side and the left side of the equation (11).

式（１２）を満たすｔｐの範囲が、最大耐力の条件から規定されるｔｐの範囲となる。

The range of tp satisfying the formula (12) is the range of tp defined from the condition of maximum proof stress.

On the left side of the above equations (8), (10), and (12), there is a plate thickness (thickness) tp of the steel column core 10, and a plate thickness tp that satisfies all of these three equations is obtained, and the steel column core 10 is used. Set the thickness.

More specifically, the lower limit of the thickness of the steel column core 10 that satisfies the above equation (3) or (4) and satisfies all of the equations (8), (10), and (12) is calculated, and the steel is steel. By setting the thickness of the column core 10 made of steel to the calculated lower limit or more, the cross section of the square steel pipe column 20 to be joined can be completely accommodated within the thickness of the steel column core 10, and in the non-diaphragm type. It is possible to provide a steel column core 10 having a necessary and sufficient yield strength.

<How to set the extra length of the extra length of the steel column core>
Next, in setting the extra length of the extra length portion, consider the case where the yield line PP is generated on the square steel pipe column 20 side at the boundary between the steel column core 10 and the square steel pipe column 20 in FIG. The yield bending moment in the steel column core 10 per unit length of the yield line is shown by the following formula (13), and the yield bending moment in the square steel pipe column 20 is shown by the following formula (14).

鋼製コラムコア１０における余長部では、以下の式（１５）を満たすことを必要とし、従って、余長部の余長ｌｐ（もしくはｌｐ'）は以下の式（１６）のうち、大きな方の値以上を満たすことを要する。

The extra length portion of the steel column core 10 needs to satisfy the following equation (15). Therefore, the extra length portion lp (or lp') of the extra length portion is the larger of the following equations (16). It is necessary to satisfy the value of.

上式（１６）を満たす余長ｌｐ（もしくはｌｐ'）を確保するようにして、鋼製コラムコア１０に対して鉄骨梁３０，４０を接合することにより、鋼製コラムコア１０と各鉄骨梁３０，４０の接合部を剛接合とすることができ、さらには、余長ｌｐ（もしくはｌｐ'）があることにより、余長が無い場合と比べて鋼製コラムコア１０の厚みを相対的に薄くすることも可能になる。

By joining the steel frame beams 30 and 40 to the steel column core 10 so as to secure an extra length lp (or lp') satisfying the above equation (16), the steel column core 10 and each steel frame beam are joined. The joints of 30 and 40 can be rigidly joined, and further, due to the extra length lp (or lp'), the thickness of the steel column core 10 is relatively smaller than that in the case where there is no extra length. It is also possible to make it thinner.

It should be noted that the configuration or the like described in the above embodiment may be another embodiment in which other components are combined, and the present invention is not limited to the configuration shown here. This point can be changed without departing from the spirit of the present invention, and can be appropriately determined according to the application form thereof.

1,2: Steel plate, 2a: Groove, 3: Welded part (submerged arc welded part), 4: Backing metal, 10: Steel column core, 20: Square steel pipe column, 30, 40: Steel beam ( H-shaped steel), 50, 60: Extra length, 100: Beam-beam joint structure

Claims (5)

It is a column-beam joint structure in which a square steel pipe column and a steel beam are joined to a non-diaphragm type steel column core.
In the steel column core, four steel plates are joined to each other via a welded portion, and the cross-sectional shape orthogonal to the stretching direction is rectangular.
The thickness of the steel plate is thicker than the thickness of the square steel pipe column.
The formation of the steel column core is higher than the formation of the steel beam, and there is an extra length portion between the upper end and / or the lower end of the steel column core and the upper end and / or the lower end of the steel beam. A beam-column joint structure characterized in that the extra length lp of the long portion has a length satisfying the following conditional equation (D) based on the breakdown line theory .

The column-beam joint structure according to claim 1 , wherein the steel column core is formed higher than the steel column core. The column-beam joint structure according to claim 1 or 2 , wherein the square steel pipe column has four corners having curvatures, and the four corners also exist within the thickness of the steel column core. The plurality of steel-framed beams joined to the steel column core are step beams having different beam formations, and the steel column cores are made higher than the steel-framed beams having a relatively high beam formation. , The beam-column joint structure according to any one of claims 1 to 3 . Any of claims 1 to 4 , wherein the thickness tp of the steel plate is a thickness that satisfies all of the following three conditional expressions (A), (B), and (C) based on the yield line theory. The column-beam joint structure described in item 1.

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