JP7195081B2 - Scallops and beam end joints using the scallops - Google Patents

Description

The present invention relates to scallops at the ends of the webs of H-section beams and beam end field joints using scallops to form H-section beam end field joints.

In steel-framed buildings in which beams, columns, and the like are made of steel-framed members, beams and columns are sometimes joined at a construction site during construction. In particular, in the case of H-section beams using H-section members as beams, the ends of the web of the H-section beam and the columns are welded or bolted at the construction site, and the ends of the upper and lower flanges of the H-section beam are joined. Beam end joints are widely and commonly used, in which beams and columns are welded at the construction site. At this time, in order to weld the end of the lower flange of the H-section beam to the column, the end of the web of the H-section beam is provided with a welding hole, usually called a scallop. The scallop is a partial notch in the end of the web of the H-section beam near the lower flange of the H-section beam, and the weld between the lower flange of the H-section beam and the column passes through this scallop. It is formed across the web of H-section beams.

The H-section member used for the H-section beam includes a welded assembled H-section and a rolled H-section steel. A welded assembly H-section is formed by welding the intersections of a pair of upper and lower flanges and a web. For this reason, fillets are provided at the intersections of the pair of upper and lower flanges with the web, the fillets being widened in the thickness direction of the web by the weld metal. Also, the rolled H-section steel is integrally formed by rolling into an H-shaped cross section consisting of a pair of upper and lower flanges and a web. At this time, a fillet portion, which is generally called a fillet portion, is provided at each intersection between the pair of upper and lower flanges and the web so as to be wide in the thickness direction of the web.

By the way, there is a risk that the lower flange of the H-section beam may break during an earthquake due to the concentration of strain on the scallops of the beam end field joints as described above, and measures to prevent this are required. For this reason, conventionally, measures have been taken to reinforce the shape of the scallops that can alleviate the concentration of strain on the scallops and the scallops.

For example, in Non-Patent Document 1, as a scallop shape that can alleviate the concentration of strain on the scallop, a shape that combines arcs with two curvature radii, and the curvature radius of the arc of the portion connected to the flange is A compound circular scallop is disclosed having a shape of 10 mm and an arc radius of curvature remote from the flange of 35 mm. Furthermore, in Non-Patent Document 1, as the shape of the scallop that can alleviate the concentration of strain on the scallop, the radius of curvature of the 1/4 circular arc of the portion connected to the flange is 10 mm. A modified B-type scallop is disclosed which is shaped with an extending straight portion. In addition, in Non-Patent Documents 2 and 3, as a scallop shape that can alleviate the concentration of strain on the scallop, a circular arc portion and a flange that extends linearly from the circular arc portion and is connected to the scallop A scalloped shape is disclosed.

On the other hand, in Patent Document 1, as a measure to reinforce the scallops, a steel frame column beam flange weld joint is a groove consisting of a beam flange, a plate-shaped member joined to the outside of the flange, and a through diaphragm of the steel frame column. A structure is disclosed in which the joint is formed by full penetration welding, the plate member is a tapered plate whose thickness linearly decreases from the thick portion to the thin portion, and the web of the beam is provided with scallops.
Further, Patent Document 2 discloses a structure in which the scallops are filled by welding or the like as a countermeasure for reinforcing the scallops.

JP 2013-7194 A JP 2015-224427 A

Architectural Institute of Japan: Technical Guideline for Steel Construction - Factory Production Edition, Japan, February 15, 2007, 5th edition, p. 208-211 Tadao Nakagome, Tetsuya Fujita: Mechanical Performance of Ends of Rolled H-beams Welded and Joined to Square Steel Pipe Columns by Diaphragm Type. Proceedings No. 455, January 1994, p. 187-196 J. M. Rickles, J.; W. Fisher, Le-Wu Lu, E.M. J. Kaufmann; Development of improved welded moment connections for earthquake-resistant design, Journal of Constructional Steel Research, 2002, No. 58, p. 565-604

However, the scallops disclosed in Non-Patent Documents 1 to 3 have the problem that strain is concentrated in the vicinity of the portion where the scallop and the lower flange of the H-section beam are connected, which is usually called the scallop bottom. In other words, there is a problem that the concentration of strain on the scalloped bottom causes a crack to occur in this portion during an earthquake, and this crack propagates to the outer surface of the lower flange of the H-shaped cross-section beam. If this crack progresses to the outer surface of the lower flange of the H-shaped cross-section beam, the lower flange of the H-shaped cross-section beam will be fractured starting from this crack, which may impair the seismic performance of the steel frame building. For this reason, a scallop shape capable of alleviating the concentration of strain on the scallop bottom is currently in demand. In addition, if strain is concentrated on the scalloped bottom and cracks occur in this area during an earthquake, the cracks that have occurred are difficult to see because there are other steel frames such as columns to which the H-shaped cross-section beams are joined. , there is a problem that diagnosis of damage after an earthquake becomes difficult.
In addition, in the structure as disclosed in Patent Document 1, although it is possible to reduce the stress at the ends of the beams, there is the problem that it takes time and effort to prepare and connect tapered plates for reinforcement. Similarly, even in the structure of Patent Document 2, there is a problem that it takes time and effort to fill the scallops by welding or the like for reinforcement.

The present invention aims to review the shape of the scallops in view of the above circumstances, and can alleviate the concentration of strain on the scallop bottom without providing a separate structure for reinforcement. To provide a scallop and a beam end field joint that can suppress the occurrence of cracks in the H-section beam and prevent the fracture of the lower flange of the H-shaped cross-section beam.

In order to solve the above problems, the present invention employs the following means.
That is, the scallop according to the present invention is provided at the end of the web of the H-section beam to form the beam end field joint of the H-section beam, the scallop on the lower flange side of the H-section beam. and a second open end located on the side opposite to the first open end, from the first open end in a direction away from the end of the web a first opening edge extending from said second opening edge, a second opening edge extending away from said end of said web, said first opening edge and said second opening edge; and the first opening edge is a toe on the web side of a fillet provided at the intersection of the web and the flange. The third opening has a first arcuate portion which is formed in an arc shape so as to intersect and whose tangent line is parallel to the inner surface of the lower flange at one end on the side of the first opening end. The edge portion has a second arc portion formed in an arc shape connecting the first opening edge portion and the second opening edge portion, and the radius of curvature of the first arc portion is the second arc portion. It is characterized by being larger than the radius of curvature of the second circular arc portion.
The purpose of the scallop according to the present invention is to alleviate the strain concentration at the bottom of the scallop on the lower flange side.

According to this configuration, with respect to the curvature radius of the second arc portion in the third opening edge connecting the first opening edge and the second opening edge, the lower flange side By increasing the radius of curvature of the first arc portion at the first opening edge located at , shear deformation of the web can be easily caused around the scallop. As a result, it is possible to relax the concentration of strain on the scalloped bottom, and to suppress the occurrence of cracks in the scalloped bottom. Here, the scalloped bottom in the present invention means the vicinity of one end of the first circular arc portion on the first opening end side. Furthermore, since the first opening edge is formed in an arc shape so as to intersect the web-side toe of the fillet, the thickness of the H-shaped cross section in the width direction is relatively large. Ductile cracking can be intentionally initiated at the web-side toe of the fillet, which is much smaller. Since this ductile crack does not propagate to the flange, it propagates stably in the axial direction along the web side toe of the fillet, which has a smaller tensile stress than the flange. It is possible to prevent the lower flange from breaking and impairing the seismic performance of the steel frame building.

Further, the first arc portion and the second arc portion are connected at a portion where the arc formed by the first arc portion and the arc formed by the second arc portion are a common tangent line. It can be a thing.
According to this configuration, the first circular arc portion and the second circular arc portion are continuously connected, so that the concentration of strain on the scalloped bottom can be further alleviated. It is possible to further suppress the occurrence of cracks.

In addition, in the scallop shape as described above, a linear portion including the first opening end and arranged in parallel with the inner surface of the nearest lower flange is provided, and the first arc portion of the first arc portion may be connected to the linear portion.
According to this configuration, a sufficient space for welding the lower flange and the column can be secured, the welding between the flange and the column can be stably performed, and welding defects can be prevented. can be done.

Furthermore, in the present invention, it is preferable that the radius of curvature of the first circular arc portion is 2.5 times or more the radius of curvature of the second circular arc portion.
As a result, the concentration of strain on the lower flange side of the scallops can be alleviated, and the occurrence of cracks from the scallops can be stably suppressed.

In addition, it is desirable that the size of the scallops as described above is as small as possible in order to stably secure the proof stress of the beam end field joints. It is preferable that the dimension of the scallop in the direction from the lower flange side to the upper flange side is 15 mm or more.

In addition, the formation of the scallops as described above is usually performed by cutting, but in order to smooth the cut surface of the circular arc portion and suppress the occurrence of cracks, it is preferable to increase the radius of curvature as much as possible in terms of cutting. . At this time, it is preferable that the scallop is formed by cutting with a cutter so that the radius of curvature of the second arc portion is 6 mm or more.

According to the present invention, concentration of strain on the scallop bottom can be alleviated without providing a separate structure for reinforcement, cracking on the scallop bottom can be suppressed, and the lower flange can be breakage can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows the outline|summary of the beam-end field joint part of embodiment. FIG. 2 is a detailed view of part A in FIG. 1; FIG. 2 is a cross-sectional view taken along a cutting line II in FIG. 1; FIG. 3 is a side view showing details of the scallops that are the first aspect of the embodiment; FIG. 11 is a side view showing details of the scallops that are the second aspect of the embodiment; FIG. 11 is a side view showing details of a scallop that is the third aspect of the embodiment; FIG. 11 is a side view showing details of a scallop that is the fourth aspect of the embodiment; FIG. 3 is a model diagram showing the entire analytical model used in the examples. It is an explanatory view for explaining a deflection angle. Analysis model No. 12 is a distribution diagram showing the equivalent plastic strain distribution in No. 12. FIG. Analysis model No. 45 is a distribution diagram showing the equivalent plastic strain distribution in 45. FIG. Analysis model No. 12 is a distribution diagram showing the plastic shear strain distribution in No. 12. FIG. Analysis model No. 24 is a distribution diagram showing the plastic shear strain distribution at 24. FIG. 4 is a graph showing the relationship between the ratio of the radius of curvature of the first circular arc portion to the radius of curvature of the second circular arc portion based on analysis results and the maximum equivalent plastic strain.

An embodiment according to the present invention will be described below with reference to FIGS. 1 to 14. FIG. FIGS. 1 and 2 show a beam end field joint 100 of this embodiment, which comprises a column 110 and a beam 1 connected to the column 110 . The column 110 is configured by axially connecting a plurality of column members 111 made of steel material and formed in the shape of a square tube.
A pair of diaphragms 112 , 112 for connecting with the beam 1 are provided at the column-beam joint 110 a where the column 110 and the beam 1 are connected. Each diaphragm 112 is a so-called through diaphragm formed in a substantially rectangular plate shape, and is disposed on both upper and lower end sides of the beam-to-column joint 110a. are sandwiched between them. Each diaphragm 112 is integrated with the column-to-beam joint 110a and the column member 111 by welding or the like with the peripheral portion projecting from the side surface 111a of the column member 111 .
In addition, the beam end field joint portion is not limited to a through-diaphragm type structure as in the present embodiment. A configuration in which the beam 1 is connected to the beam 1 via a column 110 or a diaphragm may be used.

The beam 1 is usually formed by an H-section beam. In this embodiment the beam 1 is formed by a welded assembled H-section. The beam 1 extends in one direction (horizontal direction) as a whole, and includes a web 10 and both ends of the web 10 in a direction orthogonal to the axial direction (hereinafter referred to as ends of the web (10) in a direction orthogonal to the axial direction). are sometimes referred to as "edges".) 10b, and a pair of flanges 20 connected to 10b.
The web 10 extends in the axial direction of the beam 1 with the direction orthogonal to the axial direction of the web 10 , that is, the web width direction as the height direction of the beam 1 . A pair of flanges 20 extend axially of the beam 1 and are connected to the opposite edges 10b, 10b of the web 10. As shown in FIG. The pair of flanges 20 protrude from the web 10 at substantially right angles to the thickness direction of the web 10 at both upper and lower ends of the web 10 . An axial end of the beam 1 is connected to the peripheral surface of the column 110 . Of the pair of flanges 20, 20, the lower flange 20 is called a lower flange, and the upper flange 20 is called an upper flange.
Here, in the present invention, the axial end portion of the beam connected to the column is referred to as an axial end portion (1a), and the portions of the axial end portion of the beam where the web and the flange are connected to the column are referred to as axial ends. (10a, 20a).

As shown in FIG. 3, the connecting H-shaped cross section in this embodiment has fillets 30 formed by welding at the intersections of the web 10 and the pair of flanges 20 . That is, the fillet portion 30 is formed by melting the welding material or the welding material and the base material. The fillets 30 are formed at the edges 10b, 10b of the web 10 between both web surfaces 11, 11 of the web 10 and the inner surfaces 21, 21 of the pair of flanges 20 facing toward each other. It is In other words, the fillets 30 are provided on each web surface 11, 11 so as to sandwich the web 10 at each edge 10b, 10b of the web 10. As shown in FIG.
Further, as shown in FIG. 3 , in this embodiment, the fillet portion 30 extends from the web toe portion 31 connected to the web surface 11 of the web 10 to the inner surface 21 of the flange 20 in the cross section of the beam 1 viewed in the axial direction. It is formed in a triangular shape having a linear inclined surface that connects up to the flange toe portion 32 connected to the flange, and is further formed in an isosceles triangular cross section in this embodiment. fillet height Hf, which is the size of each side along the web surface 11 of the web 10 and the inner surface 21 of the flange 20 at the fillet 30, i.e., the distance from the inner surface 21 of the flange 20 to the web toe 31; The fillet width Wf, which is the distance from the web surface 11 of the web 10 to the flange toe 32, is, for example, about 3 to 30 mm.

In addition, the cross section of the fillet portion 30 is not limited to a triangular shape. The web toe 31 to the flange toe 32 may be connected by an arc-shaped concave curved surface, and the tangent to the concave curved surface at the web toe 31 and the flange toe 32 is the web surface 11 of the web 10 and the flange 20 . may be connected so as to be parallel to the inner surface 21 of the . Also, the web toe portion 31 and the flange toe portion 32 may be connected by a convex curved surface.
In this embodiment, as described above, the fillet portion 30 is formed by performing fillet welding of the web 10 and the flange 20, and the fillet portion 30, the web 10 near the fillet portion 30, and the flange A weld is formed by each part with 20 .

The beam 1 is connected to the column 110 by the end connection structure 200 of the H-shaped cross-section member of this embodiment. That is, the end connection structure 200 of the H-shaped cross-section member of this embodiment includes the flange weld portion 40 for welding the axial end 20a of the flange 20 of the beam 1 to the column 110, and the axial end 10a of the web 10 of the beam 1 to the column. and a web weld 50 that welds to 110 . In addition, on the lower surface side of the flange welded portion 40, a backing metal that prevents the molten metal forming the flange welded portion 40 from falling out from between the groove surface 40a of the flange 20 and the column 110 is provided. .
In this embodiment, the axial end 20a of the flange 20 is welded to the diaphragm 112 of the column 110, and the axial end 10a of the web 10 is welded to the side surface 111a of the column member 111. As shown in FIG.

A scallop 60 is provided at the axial end 10a of the web 10 in the beam 1. As shown in FIG. The scallops 60 are formed on both edges 10b, 10b on the side of the axial end 10a of the web 10 on the side of the pair of flanges 20, 20, toward the axial end 20a side of the nearest flange 20 and the axial end 10a side of the web 10. , and are provided so as to penetrate the web 10 in the thickness direction. Thereby, the flange welded portion 40 is formed from one end in the width direction of the flange 20 to the other end in the width direction across the web 10 through the scallop 60 . In addition, the web welded portion 50 is formed up to scallops 60 provided on both edges 10b, 10b of the web 10. As shown in FIG.
In this embodiment, the web 10 of the beam 1 is connected to the column 110 by welding its axial end 10a to the column 110, but the method of joining the axial ends of the web of the beam is limited to welding. It may be, for example, bolted.

As shown in FIG. 4, the scallop 60 has an opening that opens toward the axial end 20a side of the nearest flange 20 and the axial end 10a side of the nearest web 10, as described above. Includes an open end. That is, the first opening end 60a located on the nearest flange 20 side and the side opposite to the first opening end 60a, in other words, on the center side in the web width direction of the web 10 sandwiched between the pair of flanges 20 and a second open end 60b positioned thereon. More specifically, the first open end 60a is formed on the inner surface 21 side of the flange 20, and the second open end 60b is formed on the axial end 10a of the web 10, respectively.

The scallop 60 also has a first opening edge 61 , a second opening edge 62 and a third opening edge 63 . The first opening edge 61 includes a first opening end 60a and extends from the first opening end 60a in the axial direction of the beam 1 in a direction away from the axial end 1a. The second opening edge 62 includes a second opening end 60b and extends from the second opening end 60b in a direction away from the axial end 1a of the beam 1, that is, toward the axial center of the beam 1. . The third opening edge 63 connects the first opening edge 61 and the second opening edge 62 .

Specifically, the first opening edge portion 61 is formed in an arc shape so as to intersect the web toe portion 31 in the fillet portion 30, and the tangent line is at one end 71a on the side of the first opening end 60a. It has a first arcuate portion 71 that is parallel to the inner surface 21 of the flange 20 .
The shape of the second opening edge 62 is not particularly limited, but in the case of the present embodiment, it extends linearly from the second opening end 60b.
Also, the third opening edge 63 has a second circular arc portion 72 that curves from the first opening edge 61 toward the second opening edge 62 .
Here, it is desirable that the curvature radius R1 of the first circular arc portion 71 is 2.5 times or more the curvature radius R2 of the second circular arc portion 72. As shown in FIG. The reason why the curvature radius R1 of the first arc portion 71 is set to 2.5 times or more the curvature radius R2 of the second arc portion 72 is that strain concentration on the flange 20 side of the scallop 60 is alleviated. Therefore, it is possible to more stably suppress the occurrence of cracks from the scallops 60 .

In addition, in the scallop 60 constituted by the first opening edge 61, the second opening edge 62 and the third opening edge 63, the direction in which the pair of flanges 20 are separated from each other (height direction of the beam 1) It is desirable that the height dimension Hs of the scallop 60 at the scallop 60 is as small as possible in order to stably secure the yield strength of the beam end field joint 100, but from the viewpoint of workability of welding the flange 20 and the column 110, It is desirable that the dimension of 60 in the direction from the lower flange 20 side to the upper flange 20 side is 15 mm or more. Furthermore, the height dimension Hs of the scallops 60 may be 35 mm or less in order to more efficiently transmit the moment to the web 10 and further reduce the strain concentration on the flange 20 side of the scallops 60 .
Further, the radius of curvature R2 of the second circular arc portion 72 may be 6 mm or more in consideration of cutting with a cutter when forming the scallops and ensuring workability.

More detailed aspects of the scallop 60 are described below.
FIG. 4 shows the scallop 60 of the first embodiment. As shown in FIG. 4, in the scallop 60 of the first aspect, the first opening edge 61 is disposed at a position on the nearest flange 20 side, and includes a first opening end 60a. It has a straight portion 73 and a first arc portion 71 connected to the first straight portion 73 .
The first straight portion 73 corresponds to the portion where the web 10 is cut out by the scallop 60 on the inner surface 21 of the nearest flange 20, and is included in the inner surface 21 of the nearest flange 20 in this embodiment. there is In addition, the first open end 60a is provided at the axial end 20a of the flange 20 that is closest thereto, and more specifically, the groove surface used when forming the flange weld portion 40 that is welded to the column 110. The end of 40a on the web 10 side is the first open end 60a.
The first circular arc portion 71 has a tangent line parallel to the inner surface 21 of the flange 20 at the position where it connects to the first straight portion 73, and gradually moves away from the flange 20 as the distance from the axial end portion 1a of the beam 1 increases. It is formed in a curved concave shape. The first circular arc portion 71 includes a fillet crossing portion 71c that is connected to the first straight portion 73 and crosses the fillet portion 30, and one end portion of the fillet crossing portion 71c opposite to the nearest flange 20. and a web forming portion 71d formed along the web surface 11 of the web 10 from the bottom.

On the other hand, the second opening edge 62 has a second straight portion 74 that is formed in a straight line including the second opening end 60 b and extends along the axial direction of the beam 1 .
The third opening edge 63 has a second arc portion 72, and one end 72a of the second arc portion 72 is connected to the first arc portion 71 of the first opening edge 61. The other end 72b is connected to the second linear portion 74 of the second opening edge portion 62. As shown in FIG.
Here, the first arc portion 71 and the second arc portion 72 are connected at a portion where the arc formed by the first arc portion 71 and the arc formed by the second arc portion 72 are a common tangent line. there is Also, at the connecting portion between the second arc portion 72 and the second straight portion 74 , the tangent line of the arc forming the second arc portion 72 and the second straight portion 74 match. Thereby, the shape of the edge of the scallop 60 composed of the first opening edge 61, the second opening edge 62 and the third opening edge 63 is continuous.
In this aspect, the height dimension Hs of the scallop 60 is determined by the distance between the first straight portion 73 and the second straight portion 74 .

Also, FIG. 5 shows a scallop 60A of the second embodiment. In addition, after giving the same code|symbol about the structure same as a 1st aspect, description is abbreviate|omitted.
As shown in FIG. 5, the first opening edge 61 in the scallop 60A of the second aspect does not have a portion corresponding to the first linear portion 73 in the first aspect, and the first arc portion 71 One end 71a on the nearest flange 20 side is the first open end 60a. One end 71 a of the first circular arc portion 71 serving as the first open end 60 a is located on the inner surface 21 of the flange 20 , and the tangent line at the one end 71 a is parallel to the inner surface 21 of the flange 20 .
In this aspect, the height dimension Hs of the scallop 60 is determined by the distance between the one end 71 a of the first circular arc portion 71 and the second linear portion 74 .

Also, FIG. 6 shows a scallop 60B of the third embodiment. Similarly, the same reference numerals are assigned to the same configurations as in the first mode, and the description thereof is omitted.
As shown in FIG. 6, in this embodiment, the groove surface 40a used to form the flange welded portion 40 extends upward (strictly speaking, the direction gradually separates from the axial end portion 1a of the beam 1 as it goes upward). ), and one end of the groove surface 40a is positioned closer to the center in the web width direction than the inner surface of the flange 20 that is the closest. One end of the groove surface 40a serves as a first open end 60a.
Specifically, the scallop 60B is configured such that the first opening edge 61 includes a first straight portion 75 including the first opening end 60a and a first arc portion 71 connected to the first straight portion 75. , and the first straight portion 75 is separated from the inner surface 21 of the flange 20 by the amount that the first opening end 60a is located on the center side in the web width direction than the inner surface of the nearest flange 20 and is formed parallel to the inner surface 21 of the flange 20 .
Here, the scallop separation distance Xs represented by the distance between the first straight portion 75 and the inner surface 21 of the flange 20 is at least the distance from the web toe portion 31 of the fillet portion 30 to the inner surface 21 of the flange 20. It is smaller than the meat height Hf. Thereby, the first arc portion 71 connected to the first straight portion 75 intersects the web toe portion 31 .
In this aspect, the height dimension Hs of the scallop 60 is determined by the distance between the first straight portion 75 and the second straight portion 74 .

Also, FIG. 7 shows a scallop 60C of a fourth embodiment. In addition, after giving the same code|symbol about the structure same as a 3rd aspect, description is abbreviate|omitted.
As shown in FIG. 7, in the scallop 60C of the fourth aspect, the first opening edge 61 does not have a portion corresponding to the first linear portion 75 in the third aspect, and the first circular arc portion 71 One end 71a is the first open end 60a. One end 71a of the first circular arc portion 71 that becomes the first open end 60a is separated from the inner surface 21 of the flange 20 as in the third aspect, and the tangent line at the one end 71a is parallel to the inner surface 21 of the flange 20. It has become.
Here, the scallop separation distance Xs represented by the distance between one end 71a of the first arc portion 71 and the inner surface 21 of the flange 20 is at least the distance from the web toe portion 31 of the fillet portion 30 to the inner surface 21 of the flange 20. is smaller than the fillet height Hf. Thereby, the first arc portion 71 connected to the first straight portion 73 intersects the web toe portion 31 .
In this aspect, the height dimension Hs of the scallop 60 is determined by the distance between the one end 71 a of the first circular arc portion 71 and the second linear portion 74 .

In the above first to fourth aspects, the first arc portion 71 of the first opening edge portion 61 and the second arc portion 72 of the third opening edge portion 63 are the same as the first arc portion 71 and the arc formed by the second arc portion 72 are connected at a common tangent line. However, the first arcuate portion 71 and the second arcuate portion 72 may not be connected at a common tangent portion, that is, they may be connected with an angle forming a boundary. Further, a linear portion is provided between the first circular arc portion 71 and the second circular arc portion 72, and the first circular arc portion 71 and the second circular arc portion 72 are indirectly connected. There may be.
Furthermore, although the second opening edge 62 is a linear portion in the present embodiment, it may be of any shape, such as an arc shape.

In the end connection structure 200 of the H-shaped cross-section member as described above, the second arc portion 72 in the third opening edge portion 63 connecting the first opening edge portion 61 and the second opening edge portion 62 is In addition, a first arc portion 71 is provided in the first opening edge portion 61 located on the flange 20 side, and the first arc portion 71 has a radius of curvature 2.5 times or more as large as that of the second arc portion 72. can be
As a result, concentration of strain on the flange 20 side of the scallop 60 can be alleviated, and crack generation from the scallop 60 can be suppressed. Since the first circular arc portion 71 is formed so as to intersect the web toe portion 31 in the fillet portion 30, even if a ductile crack occurs, the width is relatively small. Cracks can be generated near the web toe 31 where the cross-section changes from the narrow cross-section web 10 . In addition, even if a ductile crack occurs near the toe on the web 10 side, the generated crack is stably axially along the web toe 31 having a lower tensile stress than the flange 20. can propagate cracks. Therefore, in the end connection structure 200 of the H-shaped cross-section member as in the present embodiment, even if a separate structure is not provided for reinforcement, it is possible to delay the occurrence of initial cracks from the scallops and prevent the initial cracks from occurring. Even if a crack occurs, the ductile crack can be propagated so as not to lead to early fracture, and the beam end field joint 100 with higher safety can be obtained.

Moreover, by setting the height dimension of the scallop 60 to 15 mm or more, workability of welding between the flange 20 and the column 110 can be improved.
In addition, by setting the height dimension of the scallop 60 to 35 mm or less, the moment can be transmitted more efficiently even in the web 10, so that the yield bending strength of the joint between the column 110 and the beam 1 can be improved. can. Further, by keeping the height of the scallops 60 low, the moment can be transmitted more efficiently by the web 10, so the strain concentration on the flange 20 side of the scallops 60 can be further alleviated.
Furthermore, since the first arc portion 71 and the second arc portion 72 are connected by a common tangent line, the first arc portion 71 and the second arc portion 72 are smoothly connected without unevenness. Therefore, the concentration of strain can be further alleviated, and the occurrence of cracks can be suppressed more stably.
In addition, by setting the radius of curvature R2 of the second arc portion 72 to 6 mm or more, the concentration of strain in the second arc portion 72 can be alleviated, and the scallops can be easily cut and formed with a cutter. can be done.

Furthermore, the end connection structure 200 of the H-shaped cross-section member has the first opening edge 61 having the first opening end 60a and the inner surface 21 of the flange 20, as in the third aspect. A linear portion 75 arranged in parallel may be provided, and one end 71a of the first arc portion 71 may be connected to the linear portion 75, thereby providing a welder for welding the shaft end 20a of the flange 20. Sufficient space can be secured, the welding between the flange 20 and the column 110 can be stably performed, and welding defects can be prevented.

In order to demonstrate the effect of the present invention, numerical analysis was performed on a specific example of the beam end field joint portion 100 as in the above embodiment.
The finite element method was used as an analysis method, and ANSYS. Ver16 was used. FIG. 8 shows the entire model of the beam end field joint 100, which is an analysis model for analysis in this embodiment. As shown in FIG. 8, the analysis model is a cantilever beam type, and the width direction of the beam 1 is 1/2 in consideration of symmetry. The analytical model was created with three-dimensional solid elements using 8-node hexahedral elements. The material properties of the steel materials used for the column 110 and the beam 1 are the same material and the same material properties for both the column 110 and the beam 1, and the stress-strain curve obtained from the SN490B material test results was modeled with multiple linear components. used things.
As the cross section of the H-shaped cross-section beam used as the beam 1, the one shown in FIG. 3 was used with a thickness Db of 700 mm, a width B of 200 mm, a thickness tbw of the web 10 of 16 mm, and a thickness tbf of the flange 20 of 22 mm. Here, the fillet portion 30 has a fillet height Hf from the inner surface 21 of the flange 20 to the web toe portion 31 and a fillet width Wf from the web surface 11 of the web 10 to the flange toe portion 32. It is an equal isosceles triangle, and Hf=Wf=18 mm. Also, the length Lb from the side surface of the column 110 to the end of the beam 1 in the axial direction was set to 3500 mm. The thickness td (see FIG. 2) of the diaphragm 112 on the side of the column 110 to which the axial end 20a of the flange 20 is welded was set to 32 mm. Although not shown, the column 110 had an outer diameter Bc of 500 mm and a plate thickness tcf of 16 mm.

For the analysis, 53 types of models were analyzed by changing parameters relating to the shape of the scallop 60 . The shape of the scallop 60 used as an analysis model includes those shown in FIGS. The second opening edge portion 62 is composed only of the second linear portion 74, and the first circular arc portion 71 and the second circular arc portion 72 are continuously connected by a common tangent line. Parameters related to the shape of the scallop 60 include the radius of curvature R1 (mm) of the first arc portion 71, the radius of curvature R2 (mm) of the second arc portion 72, and the length of the first straight portion 73 (75). scallop distance Xs (mm), and the height dimension Hs of the scallop 60 . Arc portion termination height Hc, which is the height from the inner surface 21 of the flange 20 of the other end 71b of the first arc portion 71 on the side away from the shaft end portion 1a, is the radius of curvature R1 of the first arc portion 71 ( mm), the curvature radius R2 (mm) of the second circular arc portion 72, the scallop separation distance Xs, and the height dimension Hs of the scallop 60. It is determined geometrically. Tables 1 and 2 show the parameter values of each analysis model.

As shown in Tables 1 and 2, NO. In 1 to 25, while changing the above parameters, the curvature radius R1 of the first arc portion 71 is made larger than 1.0 times the curvature radius R2 of the second arc portion 72, and the first arc portion 71 is The web toe portion 31 intersects, that is, the arc portion terminal height Hc is set to be equal to or greater than the fillet height Hf.
On the other hand, NO. In 26 to 39, while changing the above parameters, the radius of curvature R1 of the first arc portion 71 is made larger than 1.0 times the radius of curvature R2 of the second arc portion 72, and the height Hc at the end of the arc portion is increased. The fillet height was less than Hf.
Also, NO. In 40 to 44, while changing the above parameters, the curvature radius R1 of the first arc portion 71 is set to be less than 1.0 times the curvature radius R2 of the second arc portion 72, and the arc portion end height Hc is set to Fillet height Hf or more.
Furthermore, NO. In 45 to 53, while changing the above parameters, the radius of curvature R1 of the first arc portion 71 is set to be less than 1.0 times the radius of curvature R2 of the second arc portion 72, and the height Hc at the end of the arc is The fillet height was less than Hf.

A load was applied to the ends of the beam 1 in the axial direction to deform the beam 1 in these analytical models. Then, as shown in FIG. 9, the rotation angle θ at the loading point of the beam 1 (the angle formed by the line L2 connecting both ends of the axis L1 of the beam 1 after deformation with respect to the axis L0 of the beam 1 before deformation) is The beam 1 was deformed until it reached an angle of 3.[theta]p, which is three times the rotation angle .theta.p when the entire cross section of the shaft end portion 1a is plasticized. Then, the equivalent plastic strain distribution and plastic shear strain distribution at θ=3·θp were determined by the finite element method. As an example, NO. 12 equivalent plastic strain distributions are shown in FIG. 45 shows the equivalent plastic strain distribution of .45. Also, as an example, NO. 12 plastic shear strain distribution is shown in FIG. 24 shows the plastic shear strain distribution of 24. Furthermore, the maximum equivalent plastic strain εmax (%) at the scallop bottom of the scallop 60 was determined based on the analysis results by the finite element method. Tables 1 and 2 show the maximum equivalent plastic strain εmax in each analysis model. FIG. 14 shows a graph plotting the relationship between the ratio R1/R2 of the curvature radius R1 of the first arc portion 71 to the curvature radius R2 of the second arc portion 72 and the corresponding maximum equivalent plastic strain εmax. A dotted line P1 parallel to the horizontal axis indicates εmax=20%. A dotted line Q1 parallel to the vertical axis indicates the ratio R1/R2=1.0.

From Tables 1 and 2 and FIG. 14, the maximum equivalent plastic strain εmax tends to decrease as the ratio R1/R2 of the radius of the first arc portion 71 to the radius of the second arc portion 72 increases. I understand. In particular, in analysis cases where R1/R2 exceeds 1.0, εmax stays at a low value of about 20% or less regardless of the numerical values of individual analysis parameters. That is, when R1/R2 exceeds 1.0, strain concentration on the scalloped bottom is relaxed compared to when R1/R2 is 1.0 or less. In addition, it is desirable to make R1/R2 larger in order to more stably alleviate the concentration of strain on the scallop bottom. It is desirable that As shown in FIG. 10, in the analysis model where R1/R2>1.0, for example, the analysis model NO. 12, the maximum equivalent plastic strain εmax at the scalloped bottom is suppressed, and in particular, the equivalent plastic strain near the one end 71a where the tangent line is parallel to the inner surface 21 of the flange 20 in the first arc portion 71 can be suppressed. It is accepted that there are That is, by setting R1/R2>1.0, it is possible to suppress the occurrence of cracks in the vicinity of the intersection between the web 10 and the flange 20 . Therefore, by adopting a structure similar to that of an analysis model in which R1/R2>1.0, cracks are suppressed from being generated in the first circular arc portion 71 during a maximum earthquake, and cracks occur in the flange 20. Extension toward the outer surface 22 (see FIG. 3) can be suppressed. On the other hand, in the analysis model with the ratio R1/R2≦1.0, the analysis model NO. As shown in 45, the maximum equivalent plastic strain εmax at the scalloped bottom increases, and the equivalent plastic strain near the one end 71a where the tangent line is parallel to the inner surface 21 of the flange 20 can be suppressed. It is accepted that the In this way, it is not possible to suppress the occurrence of cracks near the intersections of the web 10 and the flanges 20 . Therefore, in a structure such as the analysis model in which R1/R2 ≤ 1.0, a crack occurs in the first circular arc portion 71 at the time of a maximum earthquake, and the crack propagates toward the outer surface 22 of the flange 20. It is likely to progress. When the crack propagates toward the outer surface 22 of the flange 20, the high tensile stress acting on the flange 20 promotes brittle fracture of the flange.

Further, in the analysis model in which Hc≧Hf, the analysis model No. shown in FIG. 12, the distribution of plastic shear strain along the vicinity of the web toe portion 31 in the fillet portion 30 is widely formed in the axial direction of the beam 1, and it can be seen that the numerical value of the strain is also high. . That is, in the shape of the scallop 60 in which the first arc portion 71 intersects the web toe portion 31 because Hc≧Hf, the ductile crack occurs in the vicinity of the web toe portion 31, and the crack occurs in the cross section. The web toe portion 31 of the fillet portion 30 having a relatively small thickness in the width direction of the H-shape can be stably developed in the axial direction along the web toe portion 31 . That is, it is possible to suppress rupture due to cracks directed toward the outer surface 22 of the flange 20, and furthermore, clarify the location where the crack occurs, making it easy to visually recognize the crack after a large earthquake, and repair it quickly. It is also possible to do it easily. On the other hand, analysis model NO. where Hc<Hf. 24, as shown in FIG. 13, the first arc 71 does not intersect the web toe 31 of the fillet 30, and the second arc 72 is also included in the fillet 30. A distribution of plastic shear strain along the axial direction of the beam is not formed. Therefore, cracks occur at the first arc portion 71 . Since this crack propagates inside the fillet portion 30, it is difficult to detect the occurrence of the crack, and the crack propagates toward the outer surface 22 of the flange 20, thereby promoting brittle fracture of the flange.

As described above, the embodiments and examples of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to these embodiments and examples. etc. are also included.
For example, in the above embodiment, the H-section steel connected to the column has a welded H-section, but is not limited to this, and may be a rolled H-section steel. In the case of rolled H-section steel, the fillet portion 30 is also formed from the base material.

1 beam (H-shaped cross section beam)
1a axial end 10 web 20 flange 30 fillet 60, 60A, 60B, 60C scallop 60a first open end 60b second open end 61 first open edge 62 second open edge 63 third Opening edge portion 71 First arc portion 72 Second arc portion 73 First straight portion (straight portion)
R1 Curvature radius of the first arc portion R2 Curvature radius of the second arc portion Hs Scallop height dimension 100 Beam end field joint 110 Column 200 End connection structure of H-shaped cross-section member

Claims (7)

a scallop on the end of the web of the H-section beam to form a beam end field joint of the H-section beam, comprising:
a first open end positioned on the lower flange side of the H-section beam;
Having a second open end located on the side opposite to the first open end,
A first opening edge extending away from the end of the web from the first opening end and a second opening edge extending from the second opening end away from the end of the web When,
a third opening edge connecting the first opening edge and the second opening edge;
The first opening edge is formed in an arc shape so as to intersect with a toe on the web side of a fillet provided at a portion where the web and the lower flange intersect. has a first arc portion at one end on the open end side of the lower flange, the tangent of which is parallel to the inner surface of the lower flange;
The third opening edge portion has a second arc portion formed in an arc shape connecting the first opening edge portion and the second opening edge portion. A scallop having a radius of curvature greater than that of the second arc portion. The first arc portion and the second arc portion are connected at a portion where the arc formed by the first arc portion and the arc formed by the second arc portion are a common tangent line. 1. The scallop according to 1. The first opening edge includes the first opening end and has a linear portion arranged parallel to the inner surface of the nearest lower flange, and the first opening of the first arc portion. 3. The scallop according to claim 1, wherein one end of the scallop is connected to the straight portion. 4. The scallop according to any one of claims 1 to 3, wherein the radius of curvature of said first arcuate portion is 2.5 times or more the radius of curvature of said second arcuate portion. The scallop according to any one of claims 1 to 4, wherein the dimension of the scallop in the direction from the lower flange side to the upper flange side is 15 mm or more. 6. The scallop according to any one of claims 1 to 5, wherein the scallop is formed by cutting with a cutter, and the radius of curvature of the second arc portion is 6 mm or more. A beam end field joint formed using the scallop according to any one of claims 1 to 6.

Images