JP7143781B2 - Beam end joint - Google Patents

Description

TECHNICAL FIELD The present invention relates to a beam end joint portion in which a beam end of an H-section beam is welded to a box-shaped section column.

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, at the construction site, the end of the web of the H-section beam and the column are welded or bolted, and the upper and lower flanges of the H-section beam are welded or bolted. Beam end joints are often formed by welding the ends to the diaphragm of the column. 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 formed by partially notching 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. are formed across the web of the H-section beam through this scallop.

The H-section member used for the H-section beam includes a weld assembled H-section member and a rolled H-section steel. A welded assembly H-section member is formed by welding the intersections of a pair of upper and lower flanges and a web. For this reason, at the intersections of the pair of upper and lower flanges and the web, connecting portions are formed by the weld metal so as to be wide in the thickness direction of the web. 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, at the intersections of the pair of upper and lower flanges and the web, there are provided connecting portions, generally called fillet portions, formed 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-shaped cross-section beam may break during an earthquake due to strain concentration on the scallops of the beam end 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 and to reinforce the scallops so as to reduce the concentration of strain on 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 a scallop shape 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, and the 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, 5th Edition, February 2007 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 J. M. Rickles, J.; WFisher, Le-Wu Lu, E.M. J. Kaufmann; Development of improved welded moment connections for earthquake resistant design, Journal of Constructional Steel Research, 58 (2002), 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. That is, there is a problem that strain is concentrated on the scalloped bottom, and cracks are generated in this portion during an earthquake, and the cracks propagate 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 part 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.

On the other hand, when using a cold column such as a square steel pipe or a box-shaped cross-section column such as a welded box-shaped cross-section as a column to join an H-section beam, the degree of strain concentration at the scallop bottom is It is known to depend on stress transfer efficiency.
That is, when the plate thickness of the box-shaped cross-section column is thin, the peripheral wall of the box-shaped cross-section column (hereinafter sometimes referred to as a skin plate) tends to cause out-of-plane deformation at the beam web joint. It becomes difficult to transmit the stress of the beam web to the skin plate, so strain tends to concentrate on the scalloped bottom, which may lead to premature breakage of the beam end joint.
In order to prevent early breakage of the beam end joints, we reviewed the scallop shape and increased the thickness of the skin plate of the box-shaped cross-section column to prevent out-of-plane deformation of the skin plate at the beam web joint. , to facilitate transmission of beam web stresses to the skin plate.
However, if the thickness of the skin plate of the box-shaped cross-section column is too thick, the weight of the steel frame will increase, impairing economic efficiency, and there will be defects in the welding between the column material and the diaphragm that form the box-shaped cross-section column, or between the columns. There is a possibility that problems other than early fracture of the beam end joint may occur.

The present invention has been made in view of the above circumstances, and by suppressing the occurrence of cracks in the scalloped bottom and preventing the fracture of the lower flange of the H-shaped cross-section beam, early fracture of the beam end joint can be prevented. It is an object of the present invention to provide avoidable beam end joints.

但し、_ｗＭ_ｐは前記Ｈ形断面梁のウェブの全塑性曲げ耐力、_ｓＭ_ｕは前記箱形断面柱の面外降伏の影響を考慮した前記Ｈ形断面梁のウェブの最大曲げ耐力である。 In order to achieve the above object, a beam end joint according to the present invention is a beam end joint in which a beam end of an H-shaped cross-section beam is welded to a box-shaped cross-section column,
A scallop is provided at the end of the web of the H-section beam,
The scallops are
a first open end positioned on the lower flange side of the H-section beam;
a second open end located on a side opposite to the first open end;
a first open edge extending from the first open end away from the end of the web;
a second open edge extending from the second open end and away from the end of the web;
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 portion on the web side of a connecting portion provided at a portion where the web and the lower flange intersect. having a first arc portion at one end on the open end side, the tangent of which is parallel to the inner surface of the lower flange;
The third opening edge has a second circular arc portion formed in an arc shape connecting the first opening edge and the second opening edge,
The radius of curvature of the first arc portion is larger than the radius of curvature of the second arc portion,
The following formula (1) is satisfied, where _αw is the stress transmission efficiency of the beam-web joint, which is the joint between the web at the end of the H-shaped cross-section beam and the box-shaped cross-section column.

However, _w M _p is the total plastic bending strength of the web of the H-section beam, and _s M _u is the maximum bending strength of the web of the H-section beam considering the influence of the out-of-plane yield of the box-shaped section column. .

但し、ｔ_ｂｗは梁ウェブの厚み、ｄは梁ウェブの高さ、Ｆ_wは梁ウェブの降伏強さを表す。 Here, the total plastic bending strength _w M _p of the web of the H-shaped cross section beam (hereinafter sometimes referred to as beam web) can be expressed by the following equation (2).

where _tbw is the thickness of the beam web, d is the height of the beam web, and _Fw is the yield strength of the beam web.

但し、ｔ_ｃは箱形断面柱のスキンプレートの厚み、ｂ_ｊは箱形断面柱の降伏領域の幅、ｄ_ｊは箱形断面柱の塑性領域の高さで、柱の水平補剛材（例えばダイアフラム等）の内法間距離、Ｆ_cは角形断面柱の降伏強さ、Ｈ_wはスカラップなどによる欠損を考慮した梁ウェブの高さを表す。 Also, the maximum bending strength of the beam web considering the influence of the out-of-plane yield of the box-shaped cross-section column can be expressed by the following equation (3).

where _tc is the thickness of the skin plate of the box-section column, _{bj is the width of the yield zone of the box-section column, dj is} the height of the plastic zone of the box-section column, and the horizontal stiffener of the column ( For example, a diaphragm, etc.), F _c is the yield strength of the square section column, and H _w is the height of the beam web considering damage due to scallops and the like.

Here, the stress transmission efficiency α _w ≥ 0.48 is set because if α _w is less than 0.48, the thickness of the beam web becomes thicker, or the thickness of the skin plate of the box-shaped cross-section column becomes thinner. As a result, the skin plates of box-shaped cross-section columns tend to deform out of plane at the beam web joints, making it impossible for the beam web to bear the bending moment of the beam end, and strain tends to concentrate on the scalloped bottom. This is because there is a risk of premature breakage of the beam end joint.
Also, the upper limit of α _w is not particularly defined and can be set as appropriate. The distortion of the _scalloped bottom can be suppressed as _αw increases. It is possible to cause problems other than premature breakage of the beam end joints, such as defects in the welding between the column material and the diaphragm that form the column, or between the column materials. In addition, it is desirable to keep the plate thickness of tc so as to satisfy the following formula (4).

Since one of the objects of the present invention is to reduce the concentration of strain on the bottom of the scallops, the scallops may of course be provided on the upper flange side at the end of the web.

In the present invention, with respect to the radius of curvature of the second arc portion in the third opening edge connecting the first opening edge and the second opening edge, on the lower flange side By increasing the curvature radius of the first circular arc portion at the first opening edge located, shear deformation of the web can be easily caused around the scallop. As a result, it is possible to alleviate the concentration of strain on the scalloped bottom, and 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 portion of the connecting portion, the thickness of the H-shaped cross section in the width direction is relatively increased. Cracks can be intentionally initiated at the web-side toes of the small joints. Since this crack does not propagate in the outer surface direction of the flange, it propagates stably in the axial direction along the toe on the web side of the connecting portion, 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 out-of-plane deformation of the skin plate is suppressed as the stress transmission efficiency α _w of the beam web joint increases. In other words, the greater the stress transmission efficiency _αw at the beam web joint, the more difficult the out-of-plane deformation of the skin plate occurs at the beam web joint, and the more stable the bending moment borne by the beam end of the beam web. , strain is less likely to concentrate on the scalloped bottom. That is, the greater the stress transmission efficiency α _w of the beam web, the lower the risk of premature breakage of the beam end joint starting from the scallop bottom.
Therefore, a full-scale beam end fracture experiment was conducted to determine how much the stress transmission efficiency _αw of the beam web should be increased to avoid cracking from the scallop bottom and early fracture of the beam end joint. (This beam end fracture experiment will be described in the experimental examples to be described later.) Thus, the lower limit of the stress transmission efficiency α _w of the beam web joint was found that can avoid early fracture of the beam end joint. This lower limit is 0.48.
Therefore, in the above equation (2), the beam web thickness t _bw , the beam web height d, and the beam web yield strength F _w are appropriately set, and in the above equation (3), the skin plate of the box-shaped cross-section column thickness t _c of skin plate, width b _j of skin plate, height d _j of plastic region of box-shaped cross-section column, yield strength of box-shaped cross-section column F _c , beam web height H _w is appropriately set to satisfy α _w = _{s Mu} / _w M _p ≥ 0.48, early breakage of the beam end joint can be avoided.

Further, in the configuration of the present invention, the first circular arc portion and the second circular arc portion are tangent to a common arc formed by the first circular arc portion and the second circular arc portion. may be connected at any part.
According to such a configuration, the first circular arc portion and the second circular arc portion are continuously connected, so that the concentration of strain on the scallop bottom can be further alleviated, and the scallop It is possible to further suppress the occurrence of cracks in the bottom.

Further, in the configuration of the present invention, the first opening edge has a straight portion arranged in parallel with the inner surface of the lower flange that includes the first opening end and is closest to the first opening edge. may be connected to the linear portion at one end on the first opening end side of the circular arc portion.
According to such a 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 do.

Moreover, in the configuration of the present invention, the radius of curvature of the first circular arc portion may be 2.5 times or more the radius of curvature of the second circular arc portion.
According to such a configuration, it is possible to alleviate the strain concentration on the lower flange side of the scallops and stably suppress the occurrence of cracks from the scallops.

In addition, the size of the scallop, which is the dimension of the first opening end and the second opening end in the direction from the lower flange side to the upper flange side, stably secures the proof stress of the beam end joint. For this reason, it is desirable to make it as small as possible, but from the viewpoint of welding workability between the flange and the column, the dimension of the scallop in the direction from the lower flange side to the upper flange side may be 15 mm or more.

The scallops are usually formed by cutting a portion of the web by cutting. In order to smooth the cutting surface of the circular arc portion and suppress the occurrence of cracks, it is necessary to make the radius of curvature as large as possible in terms of cutting. preferably. Therefore, the radius of curvature of the second arc portion may be 6 mm or more.

According to the present invention, by suppressing the occurrence of cracks in the scalloped bottom formed in the web of the H-shaped cross-section beam and preventing the fracture of the lower flange of the H-shaped cross-section beam, Premature rupture can be avoided.

It is a perspective view which shows the outline|summary of the beam-end joint part of embodiment. FIG. 2 is a detailed view of part A in FIG. 1; FIG. 2 is a cross-sectional view cut along the cutting line BB 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 at 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. 7 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. It is a side view which shows the shape of the scallop in an experimental example, (a) and (b) are side views of the shape of the conventional scallop, (c) is a side view of the shape of the scallop according to the present invention. It is a side view which shows the structure of the loading test apparatus in an experimental example. It is a graph which shows the relationship between a fracture|rupture life and a plasticity factor (half amplitude) in an experimental example. It is a graph which shows the relationship between the stress transmission efficiency of a beam web and the fracture life in an experimental example.

An embodiment according to the present invention will be described below.
FIG. 1 shows a beam in which the end of an H-section beam 1 (hereinafter also abbreviated as beam 1) is welded to a box-shaped cross section pillar 110 (hereinafter sometimes abbreviated as pillar 110). 2 is an enlarged view of the A circle portion in FIG. 1. FIG.
The beam end joint 100 is formed, for example, by welding at a construction site, and includes a column 110 and a beam 1 connected to the column 110 .
The column 110 is configured by axially connecting a plurality of box-shaped column members 111 made of steel and column-to-beam joints 110a to which the beams 1 are connected. In addition, in this embodiment, the example which used the square steel pipe as the column material 111 is shown.
The column-to-beam joint 110a includes a column member 111A and a pair of diaphragms 112, 112 provided on both upper and lower end sides of the column member 111A and used for connection with the beam 1. As shown in FIG. The height dimension of the column member 111A used in the column-to-beam joint 110a is determined by the peripheral edges of the pair of diaphragms 112 and 112 and the axial ends of the pair of flanges 20 and 20 of the beam 1 to be connected, which will be described later. are large enough to face each other.
Each diaphragm 112 is a so-called through-diaphragm formed in a substantially rectangular plate shape. It is sandwiched by the material 111B. Each diaphragm 112 is integrated with the beam-to-column joint 110a and the column 111A by welding or the like in a state in which the peripheral portion protrudes outward (horizontally) from the peripheral surface 111a of each column 111A.
In addition, the column-to-beam joint is not limited to the through-diaphragm type structure as in the present embodiment. and may be connected via a pillar or diaphragm.

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 beam. The beam 1 extends in one direction (horizontal direction) as a whole and extends between the web 10 and both ends in the height direction perpendicular to the axial direction of the web 10 (hereinafter referred to as the height perpendicular to the axial direction of the web (10)). 10b, 10b and a pair of upper and lower flanges 20, 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 , 20 extend in the axial direction of the beam 1 and are connected to both upper and lower ends of the web 10 , that is, both edges 10 b , 10 b of the web 10 . Moreover, the pair of flanges 20 , 20 protrude from the web 10 at substantially right angles to the thickness direction of the web 10 at both upper and lower end portions 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 embodiment, the axial end of the beam 1 connected to the column 110 is referred to as an axial end (1a), and the web 10 and the flange 20 are connected to the column 110 at the axial end of the beam. The portions to be formed are referred to as shaft ends (10a, 20a), respectively.

In the weld assembled H-section beam 1 of this embodiment, as shown in FIG. 3, connecting portions 30 formed by welding are provided at respective portions where the web 10 and the pair of flanges 20, 20 intersect. there is That is, the connecting portion 30 is formed by melting the welding material or the welding material and the base material. The connecting portions 30 are provided at both 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, 20, which are inner surfaces facing each other. formed. In other words, the connecting portion 30 is provided on each web surface 11 , 11 so as to sandwich the web 10 at each edge 10 b , 10 b of the web 10 .
Further, as shown in FIG. 3 , in this embodiment, the connecting 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 axial cross section of the beam 1 . It is formed in a triangular shape having a linear inclined surface connecting up to the flange toe portion 32 to be connected, and is further formed in an isosceles triangular cross section in this embodiment. 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 joint 30, i.e. the distance from the inner surface 21 of the flange 20 to the web toe 31 in the height direction (beam length direction) The leg length s _w and the leg length s _f in the horizontal direction (flange width direction), which is the distance from the web surface 11 of the web 10 to the nearest flange toe 32, are, for example, about 3 to 30 mm.

Note that the cross section of the connecting 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 connecting portion 30 is formed by performing fillet welding of the web 10 and the flange 20. A weld is formed by each part.

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, as shown in FIG. 1, the end connection structure 200 of the H-shaped cross-section member of the present embodiment includes a flange weld portion 40 for welding the axial end 20a of the flange 20 of the beam 1 to the column 110, and the web of the beam 1. and a web weld 50 that welds the shaft end 10a of 10 to the post 110. As shown in FIG. In addition, on the lower surface side of the flange welded portion 40, a backing metal 45 is provided to prevent 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. there is
Further, 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 peripheral surface 111a of the column material 111A forming the column-to-beam joint 110a. ing. In this way, the beam ends of the H-section beam 1 are welded to the box-shaped section column 110 .

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 to penetrate through 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 . Also, 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.

As shown in FIG. 4, since 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, two 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, the center of the web 10 sandwiched between the pair of flanges 20, 20 in the web width direction and a flanking second open end 60b. 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 of the connecting portion 30, and the tangent line is the flange portion 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 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 radius of curvature R1 of the first arc portion 71 is set to 2.5 times or more the radius of curvature R2 of the second arc portion 72 is that the concentration of strain 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 the scallop 60 formed 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, 20 separate from each other (the height of the beam 1 It is desirable that the height dimension _Srh of the scallop 60 in the direction) be as small as possible in order to stably secure the proof stress of the beam end joint 100, but from the viewpoint of welding workability between the flange 20 and the column 110 , The dimension of the scallop 60 in the direction from the lower flange 20 side to the upper flange 20 side is preferably 15 mm or more. Further, the height dimension _Srh of the scallops 60 may be 35 mm or less in order to more efficiently transmit the moment to the web 10 as well 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 is connected to the first straight portion 73 and crosses the connecting portion 30 . and a web forming portion 71d formed along the web surface 11 of .

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 embodiment, the height dimension _Srh 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 embodiment, the height dimension _Srh 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 _Srf 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 31 of the connecting portion 30 to the inner surface 21 of the flange 20. less than the leg length height _sw in the vertical direction. Thereby, the first arc portion 71 connected to the first straight portion 75 intersects the web toe portion 31 .
In this embodiment, the height dimension _Srh of the scallop 60 is determined by the separation 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 _Srf represented by the distance between one end 71a of the first circular 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 connecting portion 30 to the inner surface 21 of the flange 20. is smaller than the leg length _sw in the height direction. Thereby, the first arc portion 71 connected to the first straight portion 73 intersects the web toe portion 31 .
In this embodiment, the height dimension _Srh 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 scallops 60 can be alleviated, and cracking from the scallops 60 can be suppressed. Since the first circular arc portion 71 is formed so as to intersect the web toe portion 31 of the connecting portion 30, even if a ductile crack occurs, the width is relatively narrow. Cracks can occur near the web toe 31 where the cross-section changes from the 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 crack can be propagated so as not to lead to early fracture, and the beam end 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. In addition, by keeping the height of the scallop 60 low, the moment can be transmitted more efficiently by the web 10, so that the strain concentration on the flange 20 side of the scallop 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 distortion 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.

但し、_ｗＭ_ｐはＨ形断面梁１のウェブ（梁ウェブ）１０の全塑性曲げ耐力、_ｓＭ_ｕは箱形断面柱１１０（より具体的には、柱梁接合部１１０ａにおいて、Ｈ形断面梁１の梁端１０ａが接合された周壁（スキンプレート））の面外降伏の影響を考慮したＨ形断面梁１の梁ウェブ接合部１２０の最大曲げ耐力である。 Furthermore, in this embodiment, if the stress transmission efficiency of the beam web joint 120, which is the joint between the web 10 of the beam end 10a of the H-shaped cross-section beam 1 and the box-shaped cross-section column 110, is _αw , the following (1 ) satisfies the formula

However, _w M _p is the total plastic bending resistance of the web (beam web) 10 of the H-shaped cross section beam 1, and _s M _u is the box-shaped cross section column 110 (more specifically, the H-shaped cross section It is the maximum bending strength of the beam web joint 120 of the H-section beam 1 considering the influence of the out-of-plane yield of the peripheral wall (skin plate) to which the beam end 10a of the beam 1 is joined.

但し、ｔ_ｂｗは梁ウェブ１０の厚み、ｄは梁ウェブ１０の高さ、Ｆ_wは梁ウェブ１０の降伏強さを表す。
なお、（２）式は、梁ウェブ全断面の塑性断面係数に梁ウェブの降伏強さを乗じることから求めることができる。 Here, the total plastic bending strength _w M _p of the beam web 10 can be expressed by the following equation (2).

However, _tbw is the thickness of the beam web 10, d is the height of the beam web 10, and _Fw is the yield strength of the beam web 10.
Equation (2) can be obtained by multiplying the plastic section modulus of the entire cross section of the beam web by the yield strength of the beam web.

但し、ｔ_ｃは箱形断面柱１１０（本実施形態では柱梁接合部１１０ａの柱材１１１Ａ）のスキンプレートの厚み、ｂ_ｊは箱形断面柱１１０の降伏領域の幅、ｄ_ｊは箱形断面柱１１０（本実施形態では柱梁接合部１１０ａの柱材１１１Ａ）の塑性領域の高さ、Ｆ_cは箱形断面柱（本実施形態では柱梁接合部１１０ａの柱材１１１Ａ）の降伏強さ、Ｈ_wはスカラップなどによる欠損を考慮した梁ウェブ１０の高さを表す。
ここで、箱形断面柱１１０の塑性領域の高さｄ_ｊは、箱形断面柱１１０の水平補剛材（本実施形態では柱梁接合部１１０ａのダイアフラム１１２）の内法間距離である。
なお、（３）式は、「日本建築学会：鋼構造接合部設計指針 第３版 ２０１７年２月」に記載されている式から求めることができる。 In addition, the maximum bending strength _s Mu of the beam web joint 120 of the H-shaped cross-section beam 1 considering the influence of the out-of-plane yield of the skin plate of the column-to-beam joint _110a of the box-shaped cross-section column 110 is given by the following equation (3): can be represented.

However, _tc is the thickness of the skin plate of the box-shaped cross-section column 110 (in this embodiment, the column material 111A of the beam-to-column joint 110a), _{bj is the width of the yield region of the box-shaped cross-section column 110, and dj is} the box shape. The height of the plastic region of the cross-sectional column 110 (the column material 111A of the beam-to-column joint 110a in this embodiment), and F _c is the yield strength of the box-shaped cross-section column (the column material 111A of the beam-to-column joint 110a in this embodiment) The height and _Hw represent the height of the beam web 10 taking into consideration the loss due to scallops and the like.
Here, the height _dj of the plastic region of the box-shaped cross-section column 110 is the inner distance between the horizontal stiffeners of the box-shaped cross-section column 110 (in this embodiment, the diaphragm 112 of the column-to-beam joint 110a).
The formula (3) can be obtained from the formula described in "Architectural Institute of Japan: Steel Structure Joint Design Guidelines, 3rd Edition, February 2017".

The larger the value of the stress transmission efficiency α _w of the beam-web joint expressed by the formula (1), the more the out-of-plane deformation of the skin plate is suppressed. Therefore, the greater the stress transmission efficiency _αw of the beam web joint 120, the more difficult it is for the out-of-plane deformation of the skin plate to occur at the beam web joint 120, and the bending moment borne by the beam web 10 of the H-section beam 1 is Since the web 10 is easily and stably transmitted, strain is less likely to concentrate on the scalloped bottom. That is, the greater the stress transmission efficiency _αw of the beam web joint 120, the lower the risk of early breakage of the beam end joint originating from the scallop bottom.
Therefore, a full-size beam-end fracture test described later was conducted to determine how much the stress transmission efficiency α _w of the beam web joint 120 should be increased to avoid early fracture of the beam-end joint. We found the lower limit of the stress transmission efficiency α _w of the beam end joint that can avoid early breakage of the joint. This lower limit is 0.48.

Therefore, in the above equation (2), the beam web thickness t _bw , the beam web height d, and the beam web yield strength F _w are appropriately set, and in the above equation (3), the skin plate of the box-shaped cross-section column thickness t _c , width b _j of the yield region of the box-shaped cross-section column, height d _j of the plastic region of the box-shaped cross-section column, yield strength F _c of the box-shaped cross-section column, beam web considering loss due to scallops, etc. By appropriately setting the height _Hw so that _{αw = sMu} / _wMp ≧ _0.48 , premature breakage of the beam end joint can be avoided.

In order to demonstrate the effect of the present invention, numerical analysis was performed on a specific example of the beam end joint 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 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 for the cross section of the H-shaped cross-section beam used as the beam 1, the thickness _{Db shown} in _FIG . was used. Here, the shape of the connecting portion 30 has a leg length sw in the height direction from the inner surface 21 of the flange 20 to the web toe portion 31, and a _leg length s in the horizontal direction from the web surface 11 of the web 10 to the flange toe portion 32. _f is an equal isosceles triangle, and s _w =s _f =18 mm. Also, the length Lb from the peripheral surface of the column 110 to the end of the beam 1 in the axial direction was set to 3500 mm. The thickness t _d (see FIG. 2) of the diaphragm 112 on the column 110 side to which the shaft end 20a of the flange 20 is welded was 32 mm. Although not shown, the column 110 had an outer diameter _{Bc of 500 mm and a skin plate thickness tcf of} the column 110 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). a height L, a scallop separation distance S _rf (mm), and a height dimension S _rh of the scallops 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 _{Srf, and the height dimension Srh of} the scallop 60. As shown in FIG. 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 Intersecting with the web toe portion 31, that is, the arc portion end height Hc is set to be equal to or greater than the leg length _sw in the height direction.
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 leg length sw in the height direction was less than _w .
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 The leg length in the height direction was set to be greater than or equal to _sw .
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 leg length sw in the height direction was less than _w .

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 axis _Lb0 of the beam 1 before deformation and the axis Lb1 of the beam 1 after deformation is calculated from the angle formed by the axis _Lb1 of the beam 1 at the beam end joint). The rotation angle component φ of the peripheral surface 111a of (the angle formed by the axis _Lc0 of the peripheral surface 111a of the column 110 before deformation and the axis _Lc1 of the peripheral surface 111a of the column 110 after deformation) is subtracted from The angle of rotation when the entire cross section of the shaft end portion 1a of the beam 1 is plasticized is _θp , and the beam 1 is deformed until the angle becomes 3· _θp , which is three times this angle. Then, the equivalent plastic strain distribution and the plastic shear strain distribution at θ=3·θ _p 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. Also, as an example, NO. 12 plastic shear strain distributions are shown in FIG. 24 shows the plastic shear strain distribution of 24. Further, the maximum equivalent plastic strain εmax (%) at the scallop bottom of the scallop 60 was obtained 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. The triangular plots in the figure indicate NO. 45 results, the other plots are no. Analysis results other than 45 are shown. A dotted line P1 parallel to the horizontal axis indicates εmax=20%, and a dotted line Q1 parallel to the vertical axis indicates the ratio R1/R2=1.0.

From Tables 1 and 2 and FIG. 14, it can be seen that 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 scalloped 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 scallop 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 circular 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 in the first arc portion 71 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≧ _sw , the analysis model No. shown in FIG. As shown in 12, the distribution of plastic shear strain along the vicinity of the web toe 31 in the connecting portion 30 is widely formed in the axial direction of the beam 1, and the strain value 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≧ _sw , the ductile crack occurs in the vicinity of the web toe portion 31, and the crack that occurs is The web toe portion 31 of the connecting portion 30 having an H-shaped cross section and having a relatively small thickness in the width direction 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, the _analytical model _NO . 24, as shown in FIG. 13, the first arc portion 71 does not intersect the web toe portion 31 of the connecting portion 30, and the second arc portion 72 is also included in the connecting portion 30. A distribution of plastic shear strain along the axial direction of is not formed. Therefore, cracks occur at the first arc portion 71 . Since this crack propagates inside the connecting 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.

Experimental example

Next, the full-scale beam end fracture test described above will be described.
Using a full-scale T-shaped partial frame test specimen, constant-amplitude cyclic loading experiments with positive and negative alternation of beams were conducted, and the effect of beam cross-section and scallop shape on the number of repetitions until fracture (fracture life) at beam end joints It was confirmed. The full-scale V-shaped partial frame test specimen refers to a specimen in which a full-scale beam is used as a cantilever and joined to a column.

Table 3 shows a list of test specimens. The test specimens are V-shaped specimens with α _w and scallop shape as parameters. It is a test piece of a column-to-beam joint using rolled H-section steel. The beams LB16A, LB16F, and TM16N have the same cross-sectional shape and plate thickness, but different scallop shapes. NH09F and TM09N have the same cross-sectional shape and plate thickness as compared to LB16F and TM16N, respectively, except that the thickness of the web is thinner.

The specimen parameters are α _w and scallop shape. The shapes of the scallops were three types (a), (b), and (c) as shown in FIG.
(a) is a side view showing part of a beam-to-column joint with a conventional scalloped beam web (corresponding to "Conventional" in Table 3). That is, as shown in FIG. 15(a), a compound circular scallop composed of a straight portion located on the column side, an arc 1 located on the flange side, and an arc 2 located on the web side. The radius of curvature of 1 (r1) is 10 mm and the radius of curvature of arc 2 (r2) is 35 mm. The scallop height ( _Srh ) is 35 mm, and the distance (L) between the groove and the scallop bottom is 10 mm. The scallop of (a) is adopted in LB16A, and the leg length (s _w ) in the height direction, which is the distance from the inner surface of the flange of LB16A to the web toe, is 22 mm.
(b) is a side view showing a portion of a beam-to-column joint having a beam web with conventional scallops and remaining fillets (corresponding to "fillet remaining" in Table 3). That is, it is a compound circular scallop composed of two circles, a straight portion located on the column side, an arc 1 located on the flange side, and an arc 2 located on the web side, and the radius of curvature (r1) of the arc 1 is 10 mm. , and the radius of curvature (r2) of arc 2 is 35 mm. Also, a fillet of 6 mm is left (symbol f in the figure is the height of the fillet). That is, the toe of arc 1 digs into the web by 6 mm from the surface of the flange. The height dimension (S _rh ) of the scallop and the distance (L) between the groove and the scallop bottom are the same as in the configuration (a) above. The scallop (b) is used for LB16F and NH09F, and the leg length (s _w ) in the height direction, which is the distance from the inner surface of the flange to the web toe, is 22 mm and 18 mm.
(c) shows a part of a column-to-beam joint provided with a beam web having a scalloped shape improved from the conventional type (a scalloped shape according to the present invention (regardless of whether expression (1) is satisfied or not). This is a plan view (equivalent to the "improved type" in Table 3), which is composed of two circles, a straight portion located on the column side and an arc 1 located on the flange side and an arc 2 located on the web side. In the compound circular scallop, the radius of curvature (r1) of arc 1 is 35 mm, the radius of curvature (r2) of arc 2 is 10 mm, and a fillet of 6 mm is left.That is, the toe of arc 1 is the flange The scallop height dimension ( _Srh ) is 30mm.The leg length ( _sw ) in the height direction, which is the distance from the inner surface of the flange to the web toe. are 19 mm, 12 mm, 17 mm and 18 mm for TM16N, TM09N, KB12N and KH14N, respectively.

As shown in Fig. 16, the test specimen was prepared by connecting the ends of a horizontal beam to a vertical column, fixing the upper and lower ends of the column to the reaction wall, and attaching an oil jack to the tip of the beam to apply a load. gone. The loading history was controlled with an amplitude of about _3θp , which is about three times the elastic component _θp of the beam end rotation angle at full plastic bending resistance.
In addition, an out-of-plane restraint jig was installed to restrain lateral buckling of the beam.

Experimental Results The number of repetitions Nf (life at break) until breakage is shown in FIGS. 17 and 18. FIG.
In FIG. 17, the horizontal axis indicates the rupture life Nf, and the vertical axis indicates the plasticity factor μ (magnitude of loading amplitude in the experiment).
Further, in FIG. 17, the solid line of the "experimental formula without scallops" is based on the evaluation formula of the following formula (4). It can be said that beam end joints with performance exceeding this solid line have the same performance as beam end joints without scallops.

ここで、Ｃ＝７．０（スカラップ無の梁端接合部の実験式）、β＝１．０／３．０である。

where C=7.0 (empirical formula for beam end joints without scallops) and β=1.0/3.0.

As shown in FIG. 17, the conventional scalloped beam of specimen LB16A has a stress transfer efficiency α _w of 0.47, which is less than the minimum value of 0.48 of the present invention, and the beam is You can see that the ends are broken.
In addition, the beam of test specimen LB16F, which has a fillet left in the conventional scallop, has a stress transmission efficiency α _w of 0.45, which is smaller than the minimum value of 0.48 of the present invention, and The beam ends are fractured, and it can be seen that the performance is better than the beam of the specimen LB16A, but it is lower than the "scallop-free formula".
In addition, the beam of the test piece NH09F, which has a fillet left in the conventional scallop, has a stress transmission efficiency α _w of 0.62, which is sufficiently larger than the minimum value of 0.48 of the present invention, but 12 times The beam end breaks after repeated repetitions, and although it is understood that the performance is better than that of the specimen LB16F, it is lower than the "scallop-free formula".
In addition, the beam with improved scallops of test specimen TM16N has a stress transmission efficiency _αw of 0.46, and a crack occurred at the bottom of the scallop, and the beam end broke after 11 repetitions. , even with the improved scallops, if the stress transmission efficiency α _w does not satisfy the minimum value of 0.48 of the present invention, it may fall below the "scallop no empirical formula".

On the other hand, in the beams with improved scallops of test specimens TM09N, KB12N, and KH14N, for which the stress transmission efficiency _αw is 0.48 or more, cracks did not occur from the bottom of the scallops and the web toe The beam end joints were fractured at 34, 29, and 23 repetitions, respectively. Since the performance often exceeds the solid line of the "scallop-free experimental formula", it can be seen that by adopting the improved scallops even at the beam end joints with scallops, it has the same performance as the beam end joints without scallops.

In FIG. 18, the horizontal axis represents the stress transmission efficiency α _w of the beam web joint, and the vertical axis represents the rupture life Nf. LB16A and LB16F had a controlled amplitude of 3.04, which exceeded the intended 3.00, and NH09F had a controlled amplitude of 2.91, which was below 3.00. It is corrected to the rupture life when controlled with an amplitude of 0.00. Specifically, the value of coefficient C is determined from formula (4) based on the experimental results for each specimen, and the rupture life is obtained by substituting the value of C and μ = 3.00 into formula (4) again. .
The thick horizontal solid line in FIG. 18 indicates the target rupture life of the scallop-free column-to-beam joint, which is, for example, about 12.7 times. The target rupture life was calculated by substituting C=7.0, which is the coefficient of the scallop-free formula, and μ=3.00 for the plasticity ratio of the controlled deformation angle into the evaluation formula (4).

Specimen LB16A with a conventional scallop shape (α _w =0.47), Specimen LB16F with a fillet-remaining scallop shape (α _w =0.45), Specimen NH09F (α _w =0.62) , and TM16N (α _w =0.46), whose scallop shape is the new type (present invention), does not satisfy the target performance, whereas TM09N (α _w = 0.62), KB12N (α _w = 0.60), and KH14N (α _w = 0.55) satisfied the target performance.
In other words, the test specimen NH09F, which has a fillet left in the conventional scallop, has a scallop shape with R1/R2 ≤ 1.0 even if the stress transmission efficiency α _w is 0.62 and 0.48 or more. Does not meet target performance. On the other hand, the improved scallops were adopted, and all the test specimens with _αw of 0.48 or more satisfied the target performance.
In addition, it can be confirmed that there is a positive correlation between the stress transmission efficiency α _w and the rupture life Nf for the four new scalloped specimens. The regression line based on the experimental results is shown by the dotted line in FIG. It can be said that the beam end joint using the new scallop can exceed the target performance. Therefore, the point where the dotted line and the solid line of the target performance intersect was set to 0.48 as the lower limit of _αw .

Also, from Equation 3, the maximum bending strength _{s Mu} of the web of the H-section beam considering the influence of the out-of-plane yield of the column is the following equation (5) when the web is considered to be effective in all sections. Therefore, the stress transmission efficiency α _w necessarily satisfies the relationship of the following formula (6).

As described above, the embodiments, examples, and experimental examples of the present invention have been described in detail with reference to the drawings. Design changes, etc. within a range that does not deviate are also included.

1 H-shaped section beam (beam)
1a shaft end 10 web 20 flange 30 connecting portions 60, 60A, 60B, 60C scallops 60a first open end 60b second open end 61 first opening edge 62 second opening 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 S _Rh Scallop height dimension 100 Beam end joint 110 Box-shaped cross-section column (column)
120 beam web joint 200 H-section member end connection structure

Claims (6)

A beam end joint in which a beam end of an H-shaped cross-section beam is welded to a box-shaped cross-section column,
A scallop is provided at the end of the web of the H-section beam,
The scallops are
a first open end positioned on the lower flange side of the H-section beam;
a second open end located on a side opposite to the first open end;
a first open edge extending from the first open end away from the end of the web;
a second open edge extending from the second open end and away from the end of the web;
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 portion on the web side of a connecting portion provided at a portion where the web and the lower flange intersect. having a first arc portion at one end on the open end side, the tangent of which is parallel to the inner surface of the lower flange;
The third opening edge has a second circular arc portion formed in an arc shape connecting the first opening edge and the second opening edge,
The radius of curvature of the first arc portion is larger than the radius of curvature of the second arc portion,
A beam characterized by satisfying the following formula (1), where _αw is the stress transmission efficiency of a beam web joint portion that is a joint portion between the web at the end of the H-shaped cross-section beam and the box-shaped cross-section column. end joint.

However, _w M _p is the total plastic bending strength of the web of the H-section beam, and _s M _u is the maximum bending strength of the web of the H-section beam considering the influence of the out-of-plane yield of the box-shaped section column. . 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. Beam end joint according to claim 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. The beam end joint according to claim 1 or 2, wherein one end on the end side is connected to the straight portion. The beam end joint according to any one of claims 1 to 3, wherein the radius of curvature of the first arc portion is 2.5 times or more the radius of curvature of the second arc portion. The beam end joint 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. The beam end joint according to any one of claims 1 to 5, wherein the second arc portion has a radius of curvature of 6 mm or more.

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