JP2017166122A - Steel beam and column-beam joint structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steel beam and a column-beam joint structure that prevent buckling of a web when exposed to horizontal external force caused by an earthquake, etc.SOLUTION: A steel beam 1 has an H-shaped cross-section with a flange 2 made of a steel material with yield strength higher than the material of a web 3, and is stiffened at an end portion. A plurality of longitudinal stiffening members 6 is disposed on the web 3 at the end portion, orthogonally to an axial direction of the beam, and at a prescribed interval in the axial direction. As such, the stiffening members 6 stiffen the end portion of the beam so as to restrict out-of-plane deformation of the web 3 at the end portion of the beam. The configuration suppresses buckling of the web accompanied by rapid decline in load resistant capacity of the member, caused by local buckling of the flange 2 at the end portion of the beam on a flexural compression side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a steel beam and a beam-column joint structure whose ends are stiffened.

When a load is applied to the steel beam that constitutes the structure due to an earthquake, etc., it is effective in shear buckling, and the local buckling of the flange is gently constrained to ensure deformation capacity and excessive strength The thing of patent document 1 is known as an example of the steel beam and column beam junction structure which can suppress a raise.
In the steel beam described in Patent Document 1, the end of the steel beam having an H-shaped cross section is stiffened by a stiffening member, and the stiffening member is provided on the web of the end of the steel beam. The longitudinal stiffener is orthogonal to the longitudinal direction of the steel beam, and the upper and lower ends of the vertical stiffener are not joined to the flange of the steel beam.

In addition, by stiffening the web with a lateral stiffener to increase the bending strength, the lateral stiffener suppresses the occurrence of local buckling of the web and prevents the early loss of yield strength. As an example of the structure, one described in Patent Document 2 is known.
The stiffening structure of the hybrid H-shaped steel beam described in Patent Document 2 includes the flange plate yield strength ff, the web plate yield strength fw, and the flange plate related to the center axis of the hybrid H-section steel web height h. The relationship between the section modulus Zf and the section modulus Zw of the web plate is expressed by a function satisfying the relationship defined by a predetermined formula, and the web plate is attached with a stiffener at the beam end joined to the column member. It is characterized by being stiffened.

In addition, the strength deterioration due to local buckling deformation of the compression flange is compensated by a reinforcing portion arranged in the vicinity of the neutral axis of the cross section of the structural member, while preventing sudden deterioration of the structural strength of the structural member. The thing of patent document 3 is known as an example of the reinforcement structure of the structural member which is going to ensure stable deformation performance. The reinforcing structure described in Patent Document 3 is such that a predetermined section including a section in which plasticization due to bending torsional deformation of the flange is taken into account near the neutral axis of the member cross section of the structural member, on the compression side of the flange by plasticization. A reinforcing portion having a predetermined cross section for compensating for the bending strength deterioration of the flange is provided in parallel with the flange.

JP 2014-51822 A Japanese Patent Laying-Open No. 2015-105543 JP-A-6-17507

  By the way, it is a large cross-section and high-strength H-shaped cross-section beam used in super high-rise buildings and large-scale distribution warehouses, and in particular, it can achieve both reduction in member weight and improvement in cross-section efficiency (bending rigidity) and bending strength. In the case of a thin-walled web and a welded and assembled H-shaped cross-section (BH) beam using a high-strength flange for the thin-walled web, the strength of the member can be suddenly lowered against a horizontal external force acting due to an earthquake or the like. There is a risk of web clipping failure. That is, the flange is thick and wide, the web is thin (the width-thickness ratio is large), and the yield stress of the flange is high with respect to the web. The BH beam has a U-shaped curved buckling on the flange at the end of the beam. If it occurs, the web is thin and low in strength, so the web in the vicinity of the compression side flange may be crushed, and there is a risk of causing clipping failure with a sudden drop in the load bearing capacity of the member.

  On the other hand, as in the steel beam described in Patent Document 1, the web at the end of the beam is stiffened by using both a vertical stiffener extending in a direction orthogonal to the axial direction of the beam and a horizontal stiffener extending in the axial direction of the beam. Even in this case, clipping failure may occur in a beam having an H-shaped cross section made of a steel material having a high yield stress of the flange relative to the web.

  Moreover, in the stiffening structure of the hybrid H-shaped steel beam described in Patent Document 2, a horizontal stiffener is installed for the purpose of reinforcing the bending strength of a low-strength web, but a vertical stiffener is installed for countermeasures against web clipping failure. As a result, clipping failure may occur in a beam having an H-shaped cross section made of a steel material having a high yield stress of the flange relative to the web.

  Furthermore, in the reinforcing structure of the structural member described in Patent Document 3, when a bending moment acts on the beam, in order to compensate for a decrease in yield strength due to torsional buckling of the compression-side beam flange, Various types of stiffening members are installed, but the effect on the clipping failure of the web is not expected, so in the H-shaped cross-section beam made of steel with a high yield stress of the flange against the web, Clipping destruction may occur. Further, in FIG. 8 of Patent Document 3, it is disclosed that a reinforcing member made of a strip is horizontally attached to an H-shaped steel beam, and that a vertical rib is provided on the web at a predetermined interval. The force is provided so that the force is better transmitted from the web to the reinforcing material, and the effect on the clipping destruction of the web as described above cannot be expected.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a steel beam and column beam joint structure capable of suppressing clipping failure of a web against a horizontal external force acting due to an earthquake or the like.

In order to achieve the above object, a steel beam of the present invention is a steel beam in which a beam end portion of a beam having an H-shaped cross section made of a steel material having a high yield stress of a flange with respect to a web is stiffened.
The web at the beam end is provided with a plurality of vertical stiffening members that are orthogonal to the axial direction of the beam and are arranged at predetermined intervals in the axial direction.

Here, in order to stiffen the beam end, the stiffening length (Ls) for providing a plurality of longitudinal stiffening members at the beam end is assumed to be plasticized by an earthquake or the like. For example, when the inner span of a column is L,
It is sufficient if Ls ≧ 0.1L.

In the present invention, the web at the beam end is provided with a plurality of vertical stiffening members that are orthogonal to the axial direction of the beam and arranged at predetermined intervals in the axial direction. The member stiffens to constrain the out-of-plane deformation that occurs in the web at the beam end. As a result, it is possible to suppress the clipping failure of the web accompanied by a sudden decrease in the proof stress of the member due to the local buckling of the flange at the beam end on the bending compression side.
In addition, the longitudinal stiffening member provided on the web at the beam end gently restrains the flange via the web and allows local buckling to occur at the flange. As a result, after the plasticization of the beam end Excellent plastic deformation performance can be imparted while suppressing breakage of the beam end welds and a sudden decrease in load bearing capacity due to an excessive increase in yield strength.

In the above configuration of the present invention, when the flange width is B,
It is preferable that at least one of the plurality of longitudinal stiffening members is provided at a distance within 2.0 B from the beam end.

Here, the distance from the beam end of the vertical stiffening member is set in this way when all of the plurality of vertical stiffening members are provided at a distance exceeding 2.0 B from the beam end. This is because the out-of-plane deformation that occurs in the web at the beam end cannot be effectively restrained, and there is a possibility that clipping of the web may occur.
Further, the distance of at least one longitudinal stiffening member from the beam end is preferably set to 50 mm or more from the viewpoint of manufacturing when the beam end is joined to a column or the like.

  According to such a configuration, since at least one of the plurality of longitudinal stiffening members is provided within a distance of 2.0 B from the beam end, local buckling of the flange at the beam end on the bending compression side Therefore, it is possible to more reliably suppress the clipping failure of the web accompanying the sudden decrease in the proof stress of the member.

  Moreover, the said structure of this invention WHEREIN: It is preferable that the vertical stiffening member in the distance within 2.0B from the said beam end part is provided in both surfaces of the said web among the said vertical stiffening members.

  According to such a configuration, the vertical stiffening members provided on both surfaces of the web at the beam end portion restrain the out-of-plane deformation that occurs on both surfaces of the web at the beam end portion, thereby further preventing clipping of the web. It can be effectively suppressed.

  Moreover, the said structure of this invention WHEREIN: It is preferable that the space | interval of the said vertical stiffening member adjacent to the axial direction of the said beam is less than 2.0B.

  Here, the interval between the longitudinal stiffening members adjacent to each other in the axial direction of the beam is set as described above. When the interval between the adjacent vertical stiffening members exceeds 2.0B, the gap is generated in the web at the beam end portion. This is because out-of-plane deformation cannot be effectively constrained, and there is a possibility that the clipping destruction of the web may occur.

  According to such a configuration, since the interval between the longitudinal stiffening members adjacent to each other in the axial direction of the beam is within 2.0B, the plurality of vertical stiffening members are not subjected to out-of-plane deformation that occurs in the web at the beam end. Since the stiffening is performed so as to restrain the web, it is possible to more reliably suppress the clipping failure of the web accompanied by a sudden decrease in the proof stress of the member due to the local buckling of the flange at the end of the beam on the bending compression side.

  Moreover, in the said structure of this invention, it is preferable that the upper-lower-end part of the said vertical stiffening member is not joined with the said flange, respectively, and the predetermined clearance gap is provided between the said flanges.

  Here, if the predetermined gap between the upper and lower ends of the longitudinal stiffening member and the flange is S and the beam formation is H, 0.005 ≦ S / H ≦ 0.05 (about 10 mm ≦ S ≦ 50 mm) It is preferable to set the gap S so as to be.

  According to such a configuration, since the upper and lower ends of the vertical stiffening member are not joined to the flange, and a predetermined gap is provided between the vertical stiffening member and the flange, a local portion of the flange is provided by the vertical stiffening member. Buckling is allowed. Therefore, the local buckling of the flange of the steel beam can be restrained gently, and an excessive increase in the proof stress can be suppressed while ensuring the deformability.

  Moreover, the said structure of this invention WHEREIN: It is preferable that the horizontal stiffening member extended in the axial direction of a beam is provided in the web of the said beam end part. That is, it is preferable that not only the plurality of vertical stiffening members but also a horizontal stiffening member extending in the axial direction of the beam is provided on the web at the beam end. Further, a plurality of the lateral stiffening members may be arranged in parallel apart from each other in the vertical direction of the web.

  According to such a configuration, since the web can be restrained by the longitudinal stiffening member and the lateral stiffening member provided on the web at the beam end portion, both local buckling and shear buckling that can occur in the web are provided. The suppression effect with respect to can be further enhanced.

  Moreover, the column beam connection structure of the present invention is characterized in that the steel beam is bonded to a column.

  In the present invention, the plurality of longitudinal stiffening members provided on the web at the beam end stiffen so as to constrain the out-of-plane deformation that occurs on the web at the beam end. Because it is possible to suppress the clipping failure of the web accompanied by a sudden decrease in the proof stress of the member due to local buckling, and gently restrain the local buckling of the flange, while ensuring deformation capacity, it is possible to suppress an excessive increase in proof stress, The strength of the steel beam will not increase excessively. Therefore, the soundness of the beam-to-column joint between the steel beam and the column can be maintained.

In the configuration of the present invention, the steel beam includes a beam joint portion joined to the column, and a beam body portion joined to the beam joint portion via a splice plate,
The splice plate may serve as the longitudinal stiffening member, and the web of the beam joint portion and the web of the beam main body portion may be joined to each other.

  According to such a configuration, the spliced plate can easily and reliably join the beam joint portion and the beam main body portion, and the strength of the member suddenly decreases due to local buckling of the flange at the beam end portion on the bending compression side. The accompanying clipping failure of the web can be suppressed.

Further, in the configuration of the present invention, the steel beam is joined to the column via the splice plate,
The splice plate may serve as the longitudinal stiffening member, and the column and the steel beam web may be joined to each other.

  According to such a configuration, the web of the column and the steel beam can be firmly joined by the splice plate, and the web is clipped with a sudden decrease in the proof stress of the member due to the local buckling of the flange at the beam end on the bending compression side. Destruction can be suppressed.

  According to the present invention, since a plurality of longitudinal stiffening members are provided at predetermined intervals on the web at the beam end, the longitudinal stiffening members restrain the out-of-plane deformation that occurs on the web at the beam end. Stiffen. Therefore, it is possible to suppress the clipping destruction of the web against a horizontal external force acting due to an earthquake or the like.

The column beam junction structure concerning a 1st embodiment of the present invention is shown, (a) is a side view and (b) is an AA line sectional view in (a). It is a graph which shows the beam end moment M / Mp by FEM analysis, and member angle (theta) / thetap relationship. The column beam joining structure concerning the 2nd Embodiment of this invention is shown, (a) is a side view, (b) is the sectional view on the AA line in (a). The column beam joining structure concerning the 3rd Embodiment of this invention is shown, (a) is a top view, (b) is a side view. The column beam joining structure concerning the 4th Embodiment of this invention is shown, (a) is a top view, (b) is a side view. The column beam joining structure concerning the 5th Embodiment of this invention is shown, (a) is a top view, (b) is a side view.

Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
1A and 1B show a column beam connection structure according to a first embodiment, in which FIG. 1A is a side view and FIG. 1B is a cross-sectional view taken along line AA in FIG.

In FIG. 1 (a) and FIG.1 (b), the code | symbol 1 shows a steel beam. The steel beam 1 has an H-shaped cross section formed by welding steel plates, and is formed so as to connect the flanges 2 and 2 between a pair of upper and lower flanges 2 and 2. Web 3.
Such a steel beam 1 is an H-shaped cross-section beam made of a steel material having a high yield stress of the flange 2 with respect to the web 3, and particularly when it is not stiffened as described later, it has a high strength and thickness. In the combination of the thick and wide flange 2 and the low-strength and thin web (large width-thickness ratio) web 3, clipping failure of the web 3 due to the U-shaped buckling of the flange 2 is likely to occur.

Examples of such a combination of the flange 2 and the web 3 include the following examples.
(1) Assuming that the yield stress level (fF) of the flange and the yield stress level (wF) of the web,
fF ≧ 385 N / mm ² , wF ≦ 325 N / mm ² (or fF / wF ≧ 385/325).
(2) d / tw ≧ 100√ (235 / wF) in the relationship between the inner height (d) of the web, the plate thickness (tw), and the yield stress (wF).
(3) As a ratio of the cross-sectional area (Aw) of the web and the cross-sectional area (Af) of the one-side flange,
Af / Aw ≧ 1.0.
(4) As a ratio of the thickness (tw) of the web and the thickness (tf) of the flange,
tf / tw ≧ 3.0.

The beam end of the steel beam 1 is stiffened by a stiffening member 5. The stiffening member 5 includes a vertical stiffener (vertical stiffening member) 6 and a horizontal stiffener (horizontal stiffening member) 7.
The vertical stiffener 6 is provided on the web 3 at the beam end of the steel beam 1 and is disposed orthogonal to the axial direction of the beam (left-right direction in FIG. 1A). Two vertical stiffeners 6 are provided at predetermined intervals in the axial direction of the beam.
The vertical stiffener 6 is formed of a rectangular plate-shaped steel plate that is long in the vertical direction, and protrudes from the surface of the web 3 outward at a substantially right angle. Further, the vertical stiffener 6 is welded so as to face both surfaces of the web 3 at the beam end. That is, a total of four vertical stiffeners 6 are provided with two pairs sandwiching the web 3.
The upper and lower ends of the vertical stiffener 6 are not joined to the flanges 2 and 2, and a predetermined gap is provided between the upper and lower ends of the vertical stiffener 6 and the flanges 2 and 2. Further, the protruding length of the vertical stiffener 6 from the web 3 is set to be equal to or shorter than the protruding length of the flange 2 from the web 3.
Note that the upper and lower end portions of the vertical stiffener 6 need not be joined to the flanges 2 and 2 by welding or the like, and may simply be in contact with the flanges 2 and 2.

Here, when the flange width of the flange 2 is B, the first vertical stiffener 6 on the side close to the beam end among the vertical stiffeners 6 and 6 adjacent in the axial direction of the beam is within 2.0 B from the beam end. The distance is provided. That is, if the distance between the beam end and the first vertical stiffener 6 on the side close to the beam end is Ls1, Ls1 ≦ 2.0B.
Moreover, the space | interval of the 1st vertical stiffener 6 and the 2nd vertical stiffener 6 adjacent to the axial direction of a beam is set within 2.0B. That is, if the interval between adjacent vertical stiffeners 6 and 6 is Ls2, Ls2 ≦ 2.0B.

Here, FEM analysis was performed with the stiffener number (stiffening interval) of the vertical stiffener at the beam end of the hybrid beam (H-section beam made of steel with high yield stress of the flange relative to the web) as the analysis variable. Since it implemented, this is demonstrated.
Under the analysis conditions as shown in Table 1, the analysis models No1 to No3 were analyzed.

Here, H (mm) is the beam formation, B (mm) is the flange width, tw (mm) is the thickness of the web, and tf (mm) is the thickness of the vertical stiffener.
Hereinafter, conditions are common to Nos. 1 to 3.
[Material properties (degree yield stress)] Flange: fF = 385N / mm ^2, the web: wF = 325N / mm ²
[Gap between vertical stiffener and beam flange s] 30mm

The analysis model models only half of the intra-column span considering symmetry, stiffens the web at one end of the beam member as a fixed end with longitudinal and lateral stiffeners, and longitudinal and lateral stiffeners on the web. The bending test type of cantilever beams with the other end corresponding to the center of the intra-column span not subjected to stiffening as the free end and the free end as the loading point.
The formulas for calculating the moment M at the beam end and the member angle θ are as follows.
M = P · (L / 2)
θ = δ / (L / 2)
Here, P is the loading point load and δ is the vertical displacement of the loading point.

The analysis results are as follows.
FIG. 2 shows the relationship between the beam end moment M / Mp and the member angle θ / θp by FEM analysis. The vertical axis and the horizontal axis are normalized by the total plastic moment Mp and the total plastic moment equivalent elastic member angle θp, respectively. In No. 1 and No. 2 in which the vertical stiffener installation interval ls> 2.0B, a sudden decrease in the proof stress was confirmed around θ / θp = 5, leading to clipping of the web, but the vertical stiffener installation interval ls ≦ 2. In No. 3 set to 0B, the clipping failure of the web did not occur until θ / θp = 10, and the suppression effect of the clipping failure of the web and the improvement of the plastic deformation ability according to the present invention were confirmed.
Therefore, as described above, if the distance between the beam end and the first vertical stiffener 6 on the side close to the beam end is Ls1, Ls1 ≦ 2.0B, and adjacent to the beam axial direction. When the interval between the first vertical stiffener 6 and the second vertical stiffener 6 is Ls2, Ls2 ≦ 2.0B.
The distance from the beam end to the first vertical stiffener 6 on the side close to the beam end is preferably set to 50 mm or more from the viewpoint of manufacturing when the beam end is joined to a column or the like.

In addition, as an example of a large cross-section and high-strength H-shaped cross-section beam used in a super high-rise building, a large distribution warehouse, or the like, assuming that the beam formation is H, about 800 mm ≦ H ≦ 2500 mm.
Further, the plate thickness (ts) of the longitudinal stiffener 6 may be about 0.7 ≦ tw / ts ≦ 1.5 with respect to the plate thickness (tw) of the web 3.
Further, the stiffening length (Ls) may be greater than or equal to the range in which the end of the beam is assumed to be plastic, and may be about Ls ≧ 0.1 L with respect to the inner span (L) of the column.

  Here, in the present embodiment, two vertical stiffeners 6 are provided at predetermined intervals in the axial direction of the beam, but three or more vertical stiffeners may be provided. Thus, when three or more vertical stiffeners are provided, it is preferable to provide them at equal intervals in the section of the stiffening length (Ls), but it is not necessarily limited to equal intervals. Even in such a case, if the interval between adjacent vertical stiffeners is Ls2, Ls2 ≦ 2.0B.

The lateral stiffener 7 is provided on the web 3 at the beam end, and is arranged in parallel with the axial direction of the beam. The lateral stiffener 7 is formed of a rectangular plate-shaped steel plate that is long on the left and right, and protrudes from the surface of the web 3 outward at a substantially right angle. Further, the lateral stiffener 7 is welded so as to face both surfaces of the web 3.
Two horizontal stiffeners 7 are arranged in the center of the web 3 in the vertical direction so as to sandwich the first vertical stiffener 6 on the side close to the beam end, and the left end of the horizontal stiffener 7 on the side close to the beam end and the column. 10 is provided with a gap in order to absorb a dimensional error generated in manufacturing and construction and from the viewpoint of manufacturability and workability, and the right end of the horizontal stiffener 7 is on the side closer to the beam end. The first vertical stiffener 6 is brought into contact with the central portion in the vertical direction or joined by welding or the like. Further, the left end of the lateral stiffener 7 on the side far from the beam end is brought into contact with the vertical center of the first vertical stiffener 6 on the side near the beam end, or is joined by welding or the like. The right end of 7 is brought into contact with the center in the vertical direction of the second vertical stiffener 6 on the side far from the beam end, or is joined by welding or the like. Thus, a total of four horizontal stiffeners 7 are provided at the end of the web 3 with the web 3 interposed therebetween.
The protruding length of the lateral stiffener 7 from the web 3 is set equal to the protruding length of the vertical stiffener 6 from the web 3.

The steel beam 1 configured as described above is joined to the column 10. Although the pillar 10 may have any structure, in the present embodiment, for example, the pillar 10 is constituted by a tubular steel pipe pillar 10. And the end part of the steel beam 1 is joined to the outer surface of the column 10 by welding or the like directly, or is joined by welding, bolt joining or the like via a joint formed on the column 10.
In addition, as a column to which the steel column 10 is joined, not only a steel column having a cross-sectional shape such as an H shape, a box shape, or a circular shape, but also a concrete filled steel tube column filled with concrete inside a box shape or a circular steel tube, Steel reinforced concrete columns are desirable.

  According to the present embodiment, a plurality of (two) vertical stiffeners (vertical stiffening members) 6 that are orthogonal to the axial direction of the beam and are arranged at predetermined intervals in the axial direction of the beam at the end 3 of the beam. Therefore, the plurality of vertical stiffeners 6 are stiffened so as to restrain the out-of-plane deformation occurring in the web 3 at the beam end. As a result, it is possible to suppress the clipping failure of the web accompanied by a sudden decrease in the proof stress of the member due to the local buckling of the flange 2 at the end of the beam on the bending compression side. Since the stiffener 6 restrains the out-of-plane deformation that occurs on both sides of the web 3 at the beam end, the clipping destruction of the web 3 can be more effectively suppressed.

In addition, the longitudinal stiffener 6 and the lateral stiffener 7 provided on the web 3 at the beam end portion gently restrain the flange 2 via the web 3 and allow local buckling to occur in the flange 2, resulting in the beam Excellent plastic deformation performance can be imparted while suppressing a sudden decrease in load bearing capacity due to the fracture of the welded end of the beam due to an excessive increase in yield strength after plasticization of the end portion. Therefore, the soundness of the column beam joint between the steel beam 1 and the column 10 can be maintained.
Furthermore, in the steel beam 1 and the beam-column connection structure having such a configuration, the stiffening member 5 provided on the web 3 at the beam end portion is constituted by the vertical stiffener 6 and the horizontal stiffener 7. , 7 can enhance the effect of suppressing both local buckling and shear buckling of the web 3.

Further, since the first vertical stiffener 6 on the side closer to the beam end of the vertical stiffeners 6 and 6 is provided within a distance of 2.0 B from the beam end, the flange of the beam end on the bending compression side is provided. It is possible to more reliably suppress the web clipping failure accompanied by a sudden decrease in the proof stress of the member due to local buckling.
Further, since the interval between the longitudinal stiffeners 6 and 6 adjacent to each other in the axial direction of the beam is within 2.0B, the stiffening is performed so that these longitudinal stiffeners 6 and 6 restrain the out-of-plane deformation generated in the web at the beam end. To do. Therefore, it is possible to more reliably suppress the clipping failure of the web accompanied by a sudden decrease in the proof stress of the member due to the local buckling of the flange at the end of the beam on the bending compression side.

(Second Embodiment)
FIGS. 3A and 3B show a column beam connection structure according to the second embodiment, in which FIG. 3A is a side view and FIG. 3B is a cross-sectional view taken along line AA in FIG.
The steel beam 1 shown in this figure is different from the steel beam 1 of the first embodiment in that four lateral stiffeners 7 are arranged on each side of the web 3, and other configurations are shown in FIG. 1 are the same as those shown in FIG.
In the present embodiment, the two lateral stiffeners 7, 7 arranged on the both sides of the web 3 respectively in the axial direction of the beam are arranged in parallel apart from each other in the vertical direction. Since the four horizontal stiffeners 7 and 7 are provided on the both sides of the web 3 at positions where the vertical length of the web 3 is divided into three equal parts, a total of eight horizontal stiffeners 7 are provided.
In the steel beam 1 and the beam-column joint structure having such a configuration, the same effect as that of the steel beam 1 and the beam-column joint structure can be obtained, and four lateral stiffeners 7 are provided on both sides of the web 3 for a total of eight. Therefore, the effect on the local buckling and shear buckling of the web 3 is greater than that shown in FIG.

(Third embodiment)
4A and 4B show a beam-column joint structure according to a third embodiment. FIG. 4A is a plan view and FIG. 4B is a side view.
In addition, the same code | symbol is attached | subjected to the same structure as the column beam connection structure shown in FIG. 1 and FIG. 3, and the description is abbreviate | omitted or simplified.

In the present embodiment, the steel beam 1 includes a beam joint portion 1a joined to the column 10 by welding or the like, and a beam body joined to the beam joint portion 1a via a splice plate 15 and a flange joining member 16. Part 1b.
The beam joint portion 1a and the beam main body portion 1b are joined by the flange joining member 16 and the splice plate 15 in a state where the flanges 2a and 2b and the webs 3a and 3b are abutted with each other.
The flanges 2a and 2b are clamped by upper and lower flange joint members 16 and 16 and then bolted, and the webs 3a and 3b are clamped by front and back splice plates 15 and 15 and bolted. In the present embodiment, the flange 2 of the steel beam 1 is configured by the flanges 2a and 2b, and the web 3 of the steel beam 1 is configured by the webs 3a and 3b.

In addition, the splice plate 15 joins the web 3a of the beam joint portion 1a and the web 3b of the beam main body portion 1b to each other in a state of serving as a vertical stiffening member. In other words, in the present embodiment, the first vertical stiffener 6 shown in FIG. 1 is substituted by the splice plate 15, and the end portion of the steel beam 1 is connected to the splice plate 15 as the vertical stiffening member, the vertical stiffener 6, Stiffened by the lateral stiffener 7.
Further, assuming that the flange width of the flanges 2a and 2b is B, the splice plate 15 is provided at a distance within 2.0B from the beam end. That is, if the distance between the beam end portion and the center portion of the splice plate 15 (center portion in the axial direction of the beam) is Ls1, Ls1 ≦ 2.0B.
Further, the distance between the center portion of the splice plate 15 and the second vertical stiffener 6 is set within 2.0B. That is, if the distance between the center portion of the splice plate 15 and the second vertical stiffener 6 is Ls2, Ls2 ≦ 2.0B.
The upper and lower ends of the splice plate 15 are not joined to the flanges 2a and 2b, and a predetermined gap is provided between the upper and lower ends of the splice plate 15 and the flanges 2a and 2b.

In addition, two lateral stiffeners 7 are disposed on both surfaces of the web 3a of the beam joint portion 1a so as to be spaced apart from each other in parallel, and between the column 10 and the left end of the lateral stiffener 7 and between the lateral stiffeners. A gap is provided between the right end portion 7 and the splice plate 15 in order to absorb a dimensional error generated in manufacturing and construction, and from the viewpoint of manufacturability and workability.
In addition, two lateral stiffeners 7 are disposed on both sides of the web 3b of the beam main body 1b so as to be spaced apart from each other in parallel, and there is a gap between the left end of the lateral stiffener 7 and the splice plate 15. Is provided. Further, the right end portion of the horizontal stiffener 7 is brought into contact with the vertical stiffener 6 or joined by welding or the like.

  According to the present embodiment, the splice plate 15 can easily and reliably join the beam joint portion 1a and the beam main body portion 1b, and the surface on which the splice plate 15 and the vertical stiffener 6 are formed on the web 3 at the beam end. Since the stiffening is performed so as to constrain the external deformation, it is possible to suppress the clipping failure of the web accompanied by a sudden decrease in the proof stress of the member due to the local buckling of the flange 2 at the end of the beam on the bending compression side.

Further, the splice plate 15, the vertical stiffener 6, and the lateral stiffener 7 provided on the web 3 at the beam end portion gently restrain the flange 2 via the web 3 to allow local buckling generated in the flange 2. As a result, excellent plastic deformation performance can be imparted while suppressing breakage of the beam end weld and a sudden decrease in load bearing capacity due to an excessive increase in yield strength after plasticization of the beam end.
Therefore, the soundness of the column beam joint between the steel beam 1 and the column 10 can be maintained.
Furthermore, in the steel beam 1 and the beam-column connection structure having such a configuration, the stiffening member 5 provided on the web 3 at the beam end is configured by the splice plate 15, the vertical stiffener 6, and the horizontal stiffener 7, By using the splice plate 15 and the stiffeners 6 and 7 together, the effect of suppressing both the local buckling and the shear buckling of the web 3 can be enhanced.

(Fourth embodiment)
5A and 5B show a column beam connection structure according to a fourth embodiment, in which FIG. 5A is a plan view and FIG. 5B is a side view.
In addition, the same code | symbol is attached | subjected to the structure which is common in the column beam connection structure shown in FIG.1, FIG3 and FIG.4, and the description is abbreviate | omitted or simplified.

In the present embodiment, the steel beam 1 includes a beam joint portion 1c joined to the column 10 by welding or the like, and a beam main body joined to the beam joint portion 1c via the splice plate 15 and the flange joining member 16. Part 1d.
In the third embodiment, the beam end portion of the steel beam 1 is configured by the beam joint portion 1a and the end portion of the beam main body portion 1b, whereas in the present embodiment, the beam joint portion 1c is used. The beam end portion of the steel beam 1 is configured. Therefore, the beam joint portion 1c in the present embodiment is longer in the axial direction than the beam joint portion 1a in the third embodiment.

The beam joint portion 1c and the beam main body portion 1b are joined by the flange joining member 16 and the splice plate 15 in a state where the flanges 2c and 2d and the webs 3c and 3d are abutted with each other.
The flanges 2c and 2d are clamped by the upper and lower flange joint members 16 and 16 and then bolted, and the webs 3c and 3d are clamped by the front and back splice plates 15 and 15 and bolted. In the present embodiment, the flange 2 of the steel beam 1 is configured by the flanges 2c and 2d, and the web 3 of the steel beam 1 is configured by the webs 3c and 3d.

  Further, the splice plate 15 joins the web 3c of the beam joint portion 1c and the web 3d of the beam main body portion 1d to each other while also serving as a vertical stiffening member. That is, in the present embodiment, the second vertical stiffener 6 shown in FIG. 1 is substituted by the splice plate 15, and the end portion of the steel beam 1 is connected to the splice plate 15 as the vertical stiffening member, the vertical stiffener 6, Stiffened by the lateral stiffener 7.

When the flange width of the flanges 2c and 2d is B, the first vertical stiffener 6 is provided at a distance within 2.0B from the beam end. That is, if the distance between the beam end and the first vertical stiffener 6 is Ls1, Ls1 ≦ 2.0B.
Further, the distance between the first vertical stiffener 6 and the central portion of the splice plate 15 is set within 2.0B. That is, if the interval between the first vertical stiffener 6 and the central portion of the splice plate 15 is Ls2, Ls2 ≦ 2.0B.
The upper and lower ends of the splice plate 15 are not joined to the flanges 2c and 2d, and a predetermined gap is provided between the upper and lower ends of the splice plate 15 and the flanges 2c and 2d.

Further, two lateral stiffeners 7 and 7 arranged in the axial direction of the beam on both surfaces of the web 3c are arranged in parallel apart from each other in the vertical direction. Four horizontal stiffeners 7 are provided at positions obtained by dividing the vertical length of the web 3 into three equal parts.
In the axial direction of the beam, two horizontal stiffeners 7 are arranged so as to sandwich the vertical stiffener 6, and there is a gap between the left end of the horizontal stiffener 7 on the side close to the beam end and the column 10 in terms of manufacturing and construction. In order to absorb dimensional errors caused by the above and from the viewpoint of manufacturability and workability, a gap is provided, and the right end of the horizontal stiffener 7 is brought into contact with the vertical stiffener 6 or joined by welding or the like. Further, the left end portion of the horizontal stiffener 7 on the side far from the beam end is brought into contact with the vertical stiffener 6 or joined by welding or the like, and between the right end portion of the horizontal stiffener 7 and the splice plate 15, A gap is provided in order to absorb dimensional errors that occur during manufacturing and construction, and from the viewpoints of manufacturability and workability.

  According to the present embodiment, similarly to the third embodiment, the beam joint portion 1c and the beam main body portion 1d can be easily and reliably joined by the splice plate 15, and the vertical stiffener 6 and the splice plate 15 can be joined. Is stiffened so as to constrain the out-of-plane deformation that occurs in the web 3c at the beam end, so that the clipping failure of the web accompanying a sudden decrease in the proof stress of the member due to local buckling of the flange 2 at the beam end on the bending compression side Can be suppressed.

Further, the splice plate 15, the vertical stiffener 6 and the horizontal stiffener 7 provided on the web 3 (3 c) at the beam end portion gently restrain the flange 2 via the web 3, and local buckling occurring in the flange 2 is prevented. As a result, excellent plastic deformation performance can be imparted while suppressing breakage of the beam end welded portion and a sudden decrease in load bearing capacity due to an excessive increase in the yield strength after plasticization of the beam end portion.
Therefore, the soundness of the column beam joint between the steel beam 1 and the column 10 can be maintained.
Furthermore, in the steel beam 1 and the beam-column connection structure having such a configuration, the stiffening member 5 provided on the web 3 at the beam end is configured by the splice plate 15, the vertical stiffener 6, and the horizontal stiffener 7, By using the splice plate 15 and the stiffeners 6 and 7 together, the effect of suppressing both the local buckling and the shear buckling of the web 3 can be enhanced.

(Fifth embodiment)
6A and 6B show a column beam connection structure according to a fifth embodiment, where FIG. 6A is a plan view and FIG. 6B is a side view.
The steel beam 1 shown in this figure is different from the steel beam 1 shown in FIG. 3 in that the end of the web 3 of the steel beam 1 is joined to the column 10 by a splice plate 15a. 3 are the same as those shown in FIG.

The splice plate 15a is substantially half as long as the beam in the axial direction of the splice plate 15. The splice plate 15a is bolted to the web 3 on one side of the web 3. The splice plate 15a is joined to the column 10 by welding or the like at the construction site.
In the steel beam 1 and the column beam joint structure having such a configuration, the same effect as that of the second embodiment can be obtained, and there is an advantage that the column 10 and the steel beam 1 can be firmly joined.

  As mentioned above, although the example of embodiment of this invention was demonstrated in detail, all the embodiment mentioned above showed only the example of actualization in implementing this invention, and these are the technical aspects of this invention. The range should not be construed as limiting.

DESCRIPTION OF SYMBOLS 1 Steel beam 1a, 1c Beam joint part 1b, 1d Beam main-body part 2, 2a, 2b, 2c, 2d Flange 3, 3a, 3b, 3c, 3d Web 5 Stiffening member 6 Vertical stiffener (vertical stiffening member)
7 Lateral stiffener (lateral stiffener)
10 pillar 15 splice plate 16 flange joint member

Claims (9)

A steel beam in which the beam end of a beam having an H-shaped cross section made of a steel material having a high yield stress of the flange with respect to the web is stiffened,
A steel beam characterized in that a plurality of vertical stiffening members perpendicular to the axial direction of the beam and arranged at predetermined intervals in the axial direction are provided on the web at the beam end. If the flange width is B,
The steel beam according to claim 1, wherein at least one of the plurality of longitudinal stiffening members is provided at a distance within 2.0 B from the beam end.   3. The steel beam according to claim 2, wherein among the vertical stiffening members, vertical stiffening members that are within a distance of 2.0 B from the beam end are provided on both surfaces of the web. If the flange width is B,
The steel beam according to any one of claims 1 to 3, wherein an interval between the longitudinal stiffening members adjacent to each other in the axial direction of the beam is within 2.0B.   The upper and lower ends of the vertical stiffening member are not joined to the flange, respectively, and a predetermined gap is provided between the flange and the flange. Steel beam described.   The steel beam according to any one of claims 1 to 5, wherein a lateral stiffening member extending in the axial direction of the beam is provided on the web of the beam end portion.   A steel beam according to any one of claims 1 to 6, wherein the steel beam is joined to a column. The steel beam includes a beam joint portion joined to the column, and a beam body portion joined to the beam joint portion via a splice plate,
The column beam according to claim 7, wherein the splice plate joins the web of the beam joint portion and the web of the beam main body portion to each other in a state of serving also as the longitudinal stiffening member. Junction structure. The steel beams are joined to the pillars via the splice plate;
The column-beam joint structure according to claim 7, wherein the splice plate joins the column and the web of the steel beam to each other in a state of serving as the longitudinal stiffening member.

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