JP2010090595A - Joint structure of pillar and beam and beam member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joint structure of a pillar and a beam of a pillar/beam frame of a steel structure which makes possible the adoption of a steel frame having a small cross section for a beam and which does not need a high degree of welding technique during construction. <P>SOLUTION: In the joint structure 10 of the pillar 20 and the beam 30, the beam 30 is made of H-beam, and the joint structure 10 is provided with a diaphragm 21 and a leaf-formed cover plate 40. The diaphragm 21 is projected from the surface of the pillar 20, and the upper-and-lower flanges 31 of the beam 30 are welded and connected to the diaphragm 21. One end of the leaf-formed cover plate 40 is connected to the pillar 20, and the leaf-formed cover plate 40 is attached to the outer peripheral surface of the flange 31 of the beam 30. The part of the cover plate 40 other than the end on the pillar side of the outer peripheral edge is continuously connected to the outer peripheral surface of the flange 31 by fillet welding 41. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a column-to-beam joint structure capable of reducing a beam cross section.

  In steel-framed column beam structures, when an external force such as an earthquake or wind is input, generally, the stress of the beam is maximized at the end, so that the end of the beam is required to have high strength. Therefore, conventionally, a steel frame having a large cross section has been used as a beam having the required strength at the beam end. However, the stress at the center of the beam is smaller than at the beam end. For this reason, it is not economical to use a steel frame having a large cross section as described above.

Therefore, as shown in FIG. 10A, the side plate 640 is welded to both sides of the flange 31 of the H-shaped steel constituting the beam 30, and the side plate 640 is connected to the column together with the flange. (For example, refer to Patent Document 1). In this way, by welding the side plate 640, as shown in the graph of FIG. 10B, the cross-sectional rigidity and strength of the beam to which the side plate is attached are increased, and the bending acting on the beam 30 is increased. When the moment increases, the first yielding point (that is, the cross section where the strength of the beam is determined: hereinafter referred to as a critical cross section) is located closer to the center than the beam end of the side plate 640. Since the bending moment acting on the cross section at this portion is smaller than that at the beam end, an H-shaped steel having a small cross section as compared with the case without the side plate 640 can be adopted as the steel material constituting the beam 30.
Japanese Patent Laid-Open No. 11-210158

  Here, since the stress flows from the flange of the beam to the side plate at the end on the beam center side of the part where the side plate is attached, the outer end of the flange on the beam center side that is the weld of the flange and the side plate Will concentrate stress.

However, the weld end of the flange and the side plate is the start or end of welding, and is easily affected by heat. If the weld quality is poor, the weld end is easily broken and the toughness is reduced. For this reason, the welding operation of the side plate has to be welded so that the toughness does not decrease at the weld end portion on the beam center side, and an advanced welding technique is required. In addition, the side plate may be inclined due to the heat effect of welding, which requires high technology in production.
In the side plate method, the beam flange spreads at the end, so it is necessary to make the column core and beam core substantially the same. For mounting the outer wall around the outer periphery of the building, the slab can be ejected or attached separately. Hardware is required.

The present invention has been made in view of the above problems, and the purpose thereof is to adopt a steel frame having a small cross section as a steel material constituting the beam, and an advanced welding technique is unnecessary during construction. It is to provide a steel beam-to-column connection structure.
Another object of the present invention is to make it possible to mount the beam eccentrically with respect to the column in order to eliminate the need for a slab or a special hardware for mounting the outer wall around the outer periphery.

  The column beam connection structure of the present invention is a column-beam connection structure, wherein the beam is made of H-shaped steel, one end is connected to a side surface of the column, and is attached to the flange surface of the H-shaped steel. A cover plate made of a steel plate is provided, and the cover plate is continuously fillet welded to the flange surface at the outer peripheral edge except for the column side end.

  In the above-mentioned column beam connection structure, the column may be provided with a diaphragm at a position corresponding to the upper and lower flanges of the H-shaped steel, and the upper and lower flanges of the beam and a cover plate may be connected to the diaphragm. .

  In addition, the cover plate may be formed in a shape such that the width is narrowed toward the end portion on the beam center side. At this time, the beam has the bending moment generated with an increase in load. The cross-sectional design may be such that the position of the end portion of the cover plate on the center side of the beam first reaches the bending strength.

  In addition, the cover plate may be formed with a reduced width portion that narrows in the middle portion in the longitudinal direction of the beam. At this time, the beam has the above-described bending moment generated with an increase in load. The cross-sectional design may be such that the position of the reduced width portion of the cover plate first reaches the bending strength.

  The beam member of the present invention is a beam member made of H-shaped steel, and includes a cover plate made of a steel plate attached to the flange surface of the H-shaped steel, and the cover plate is connected to a column on the outer peripheral edge thereof. The portion excluding the end on the side to be formed is continuously fillet welded to the flange surface.

According to the present invention, by attaching the cover plate, the end portion on the beam center side of the cover plate having a small bending moment acting compared to the end portion becomes a critical cross section, so that the cross section of the beam can be suppressed. In addition, because the cover plate is attached to the beam by fillet welding at the outer periphery excluding the column side edge, welding is continuous in the critical cross section, and this part is less likely to be affected by heat. Even without it, welding work can be performed.
Further, in the present invention, the beam flange width is not increased unlike the side plate method, so that it is possible to attach the beam eccentrically with respect to the column, particularly by decentering the beam around the outer periphery of the building. This eliminates the need for a spring slab or special hardware for mounting the outer wall.

Hereinafter, a first embodiment of a column-to-beam joint structure in a steel-framed column beam frame according to the present invention will be described with reference to the drawings.
1A and 1B show a joint structure 10 of a column 20 and a beam 30 according to this embodiment, where FIG. 1A is a top view and FIG. 1B is a side view. 2 is an enlarged cross-sectional view in a direction crossing the beam 30 at the upper part of the beam 30, and FIG. 3 is an enlarged view of a portion A in FIG. As shown in FIG. 1, the joining structure 10 of this embodiment is a structure for joining the column 20 and the beam 30 in a steel-framed column beam frame.

  The beam 30 is made of H-shaped steel having a narrower flange width than the steel pipe constituting the column 20. A cover plate 40 is attached to the outer surface of the upper and lower flanges 31 of the beam 30 so that the ends on the beam end side (left side in FIG. 1) coincide. The cover plate 40 is formed so that the portion from the end on the beam end side to the intermediate portion has a constant width, and the width gradually decreases from the intermediate portion toward the beam central portion (right side in FIG. 1). Made of steel plate. The cover plate 40 is attached to the outer surface of the flange 31 by applying fillet welds 41 to the portion of the outer peripheral edge excluding the edge on the beam end side. The length of the cover plate 40 is determined so that the weld length of the fillet weld 41 that can withstand the stress transmitted from the flange 31 to the cover plate 40 can be secured. In the present embodiment, the cover plate 40 is shown to be narrower than the flange 31. However, the cover plate 40 may have the same width as the flange 31 or larger than the flange width.

The column 20 is made of a steel pipe having a rectangular cross section. At the height position where the flange 31 of the beam 30 of the column 20 is connected, a through diaphragm type diaphragm 21 projects from the surface. The diaphragm 21 is constructed integrally with the pillar 20 by dividing a steel pipe constituting the pillar 20 into a plurality of parts and sandwiching a steel plate at a height corresponding to the upper and lower flanges 31 of the beam 30.
Further, the diaphragm may be an inner diaphragm that is formed in a pillar through a pillar.

  In the joining structure 10 of this embodiment, the beam 30 previously welded with the cover plate 40 is attached to the side of the pillar 20 so that the upper and lower flanges 31 and the diaphragm 21 attached to the pillar 20 are located at the same height. The web 32 is welded to the column 20, and the flange 31 and the cover plate 40 are connected to the diaphragm 21 by full penetration welding 42.

  FIG. 4B is a graph showing the bending strength of the beam 30 and the distribution of bending moment generated in the beam 30 when an external force is applied to the column beam frame. The horizontal axis represents the beam shown in FIG. It is shown corresponding to 30 positions. As shown in the figure, the bending strength of the beam 30 joined by the joining structure 10 of the present embodiment is such that the width of the cover plate 40 is constant from the beam end to the position corresponding to the middle part of the cover plate 40. Therefore, it becomes a constant value. Further, in the portion from the position corresponding to the middle portion of the cover plate 40 to the position corresponding to the end portion on the beam center side of the cover plate 40, the cover plate 40 has a shape in which the width gradually decreases toward the beam center side. Therefore, along with this, the bending strength of the beam gradually decreases. The bending strength of the beam in the portion closer to the center of the beam than the position corresponding to the end on the center side of the beam of the cover plate 40 is a constant value.

  On the other hand, the bending moment acting on the beam 30 is maximized at the end of the beam and decreases in proportion to the distance from the end toward the center of the beam 30. In the present embodiment, when the bending moment acting on the beam 30 increases, the cover plate 40 first has a bending moment at the end portion on the beam center side at a position where it hits the end portion on the beam center side of the cover plate 40 of the beam 30. The width, thickness, length, and strength of the cover plate 40 are designed to exceed the bending strength of the beam 30 (ie, yield first). Thereby, the edge part of the beam center side of the cover plate 40 becomes a critical section.

  Here, when designing the required cross section of the beam 30, it is necessary to design the yield so as not to yield in the critical cross section with respect to the design bending load. When a cover plate or the like is not provided as in the prior art, the bending strength of the beam is constant regardless of the position, so that the critical cross section is located at the beam end and the beam end can withstand the bending strength. The cross section needs to be designed.

  On the other hand, according to the present embodiment, the position corresponding to the end of the cover plate 40 on the beam center side of the cover 30 is a critical cross section. The bending moment acting on the beam 30 when an external force is applied to the column beam frame is smaller at the beam center than at the beam end. Therefore, according to the present embodiment, the necessary cross section of the steel material constituting the beam 30 is provided. Can be suppressed. That is, as the H-shaped steel constituting the beam 30, one having a smaller width, height, or plate thickness than the conventional one, or one having a low strength can be employed.

  Further, as described above, in the present embodiment, since the outer peripheral edge except the edge on the beam end side of the cover plate 40 is connected by the fillet weld 41, the welding becomes continuous in the critical cross section, resulting in a thermal effect. The end of the easy fillet weld is not located in the critical section. For this reason, even if there is no advanced welding technique, the operation | work which welds the cover plate 40 to the beam 30 can be performed.

  In addition, since stress tends to be concentrated on a sharp corner, usually, if there is a sharp corner on the cover plate 40, the fillet weld 41 around this portion tends to break. However, in the present embodiment, since the cover plate 40 has a shape in which the width gradually decreases from the intermediate portion toward the center of the beam, the corner corner portion becomes an obtuse angle and the force that the flange 31 bears is applied from the flange 31 to the cover plate 40. It is possible to alleviate the stress concentration that occurs during transmission to

  Conventionally, since side plates are attached to both sides of the beam 30 in the horizontal direction, the beam 30 cannot be connected to the horizontal end of the column, but in this embodiment, the upper and lower surfaces of the beam 30 are not connected. Since the cover plate 40 is attached to the beam 20, the beam 30 can be connected to the horizontal end of the column 20 so that the degree of freedom of the joining position of the beam 30 to the column 20 is increased. In this way, by attaching the beam 30 to the column 20 in an eccentric manner, a protruding slab for mounting the outer wall and hardware for mounting are unnecessary around the outer periphery of the building.

  In the present embodiment, the case of using the cover plate 40 in which the end portion on the beam center side is formed in a straight line has been described. For example, as shown in FIG. A cover plate 140 formed in an arc shape may be used. The cover plate 140 having such a shape can be attached to the beam 30 by fillet welding the outer peripheral edge other than the beam end, and the corner corner on the beam center side of the cover plate 140 becomes an obtuse angle, resulting in stress concentration. Can be relaxed.

  Further, as shown in FIG. 6A, a cover plate 240 having a reduced width portion 240A whose width is reduced in a smooth arc shape at the intermediate portion may be used. When such a cover plate 240 is used, the critical cross section is located at the reduced width portion 240A as shown in the graph of FIG. 6B, but the outer peripheral edge of the cover plate 240 is beamed by the fillet weld 41. Since the end of the fillet weld 41 is not located at a position corresponding to the critical section, it is possible to prevent breakage of the welded section in the critical section. When the cover plate 240 having such a configuration is employed, since the critical cross section is located in the reduced width portion 240A, a yield strength that yields a prior yield to the bending moment generated in the beam 30 is obtained at the position of the critical cross section. What is necessary is just to use the steel material which has as the beam 30. FIG.

In addition, the cover plates attached to the upper and lower flanges 31 in the above embodiment can have different thicknesses, or one of them can be omitted. For example, as shown in FIG. 7, when a bending moment that generates a tensile force on the upper side of the beam 30 is applied to a column beam joint in which a concrete floor 50 is constructed on the beam 30. The cover plate 40A attached to the beam 30 and the upper flange 31 and the upper flange 31 resist the tensile force. On the other hand, when a bending moment that generates a compressive force acts on the upper side of the beam 30, the cover plate 40B and the lower flange 31 attached to the beam 30 and the lower flange 31 bear the tensile force. Since the concrete floor 50 bears the compressive force, the tensile force borne by the lower cover plate 40B is reduced accordingly. For this reason, the thickness of the cover plate 40B attached to the lower flange 31 can be reduced or omitted.
On the contrary, when the state in which the tensile force is applied to the upper side of the beam 30 and the state in which the tensile force is applied to the lower side are repeated, the lower flange 31 is greatly repeated compared to the upper flange 31 to which the concrete floor 50 is attached. Since it becomes easy to break by receiving stress, the thickness of the lower cover plate 40B is made larger than the upper cover plate 40A, and the strength on the lower flange 31 side is increased compared to the upper flange 31 side. it can.
In the present embodiment, the case where one cover plate 40 is attached to each of the outer surfaces of the upper and lower flanges has been described. However, the present invention is not limited to this, and as shown in FIG. If welding is possible, a plurality of cover plates 440 may be attached.
In the above embodiment, the cover plate is attached to the upper surface of the upper flange and the lower surface of the lower flange. However, the present invention is not limited to this, and as shown in FIG. A cover plate 540 may be attached to the upper surface of 31. In such a case, cover plates 540 may be attached to both surfaces of the flange 32 with the web 32 interposed therebetween, as shown in FIG.

  In the present embodiment, the diaphragm type diaphragm 21 is provided through the column 20. However, the present invention is not limited to this, and an outer diaphragm type diaphragm or an inner diaphragm type diaphragm may be provided. Further, in this embodiment, the flange 31 is connected to the diaphragm 21 protruding from the surface of the column 20 by full penetration welding 42, but the diaphragm does not necessarily have to protrude from the surface of the column 20 and is flush with the column 20. Further, the flange 31 may be attached to the diaphragm or the column surface and welded.

  Further, the cover plate 40 does not need to be attached to the flange 31 in advance, and the cover plate 40 may be attached after the beam 30 is connected to the column 20.

  Moreover, in this embodiment, although the pillar 30 was comprised with the rectangular steel pipe, you may comprise not only this but steel pipe concrete. In this case, it is not always necessary to provide a diaphragm on the pillar.

The junction structure of the pillar of this embodiment and a beam is shown, (A) is a top view, (B) is a side view. It is an expanded sectional view of the direction which crosses the beam of the upper part of a beam. It is an enlarged view of the A section of FIG. (A) shows the beam-column joint structure of the present embodiment, (B) is a graph showing the bending strength of the beam and the distribution of bending moment generated in the beam when an external force is applied to the column beam frame, The horizontal axis corresponds to the beam position shown in FIG. It is a figure which shows the case where the cover plate which formed the edge part of the beam center side in the smooth circular arc shape was used. (A) is a figure which shows the case where the cover plate provided with the reduced width part to which a width | variety reduces to a smooth circular arc shape in the intermediate part is used, (B) is the bending strength of the beam in such a case, and a column It is a graph which shows distribution of the bending moment which arises in a beam when external force acts on a beam frame, and a horizontal axis is made to correspond to a position of a beam shown in (A). It is a vertical sectional view showing a beam-column joint when a concrete floor is constructed on the upper part of the beam. It is a figure which shows a column beam junction part at the time of dividing | segmenting a cover plate. The case where a cover plate is attached to the lower surface of the upper flange and the upper surface of the lower flange is shown, (A) is a vertical cross-sectional view, and (B) is an enlarged cross-sectional view in a direction crossing the upper beam of the beam. (A) is a figure which shows a mode that the column beam was connected using the conventional side plate, (B) is the bending strength of a beam in such a case, and when external force acts on a column beam frame, It is a graph which shows distribution of the bending moment which arises, and the horizontal axis is made to correspond to the position of the beam shown to (A).

Explanation of symbols

10, 110, 210, 410, 510 Joint structure 20 Column 21 Diaphragm 30 Beam 31 Flange 32 Web 40, 40B, 140, 240, 440, 540 Cover plate 41 Fillet weld 50 Floor

Claims (7)

It is a joint structure of columns and beams,
The beam is made of H-shaped steel,
A cover plate made of a steel plate, one end of which is connected to the side surface of the column and attached to the flange surface of the H-shaped steel;
The cover plate has a column beam joint structure in which a portion of the outer peripheral edge excluding the column side end is continuously welded to the flange surface. The beam-column joint structure according to claim 1,
The column is provided with a diaphragm at a position corresponding to the upper and lower flanges of the H-shaped steel,
A beam-column joining structure, wherein upper and lower flanges and a cover plate of the beam are connected to the diaphragm. The beam-column joint structure according to claim 1 or 2,
The beam-to-column connection structure according to claim 1, wherein the cover plate is formed in a shape such that a width thereof decreases toward an end portion on a beam center side. The beam-column joint structure according to claim 3,
The beam-to-column connection is characterized in that the beam is cross-sectionally designed so that the position of the end portion on the beam center side of the cover plate first reaches the bending strength with respect to a bending moment generated with an increase in load. Construction. The beam-column joint structure according to claim 1 or 2,
The said cover plate is a column beam connection structure characterized by the reduced width part which becomes narrow in the longitudinal direction intermediate part of the said beam being formed. The beam-column joint structure according to claim 5,
The beam-to-column connection structure is characterized in that the beam is cross-sectionally designed so that a position of the reduced width portion of the cover plate first reaches a bending strength against a bending moment generated with an increase in load. A beam member made of H-shaped steel,
A cover plate made of a steel plate attached to the flange surface of the H-shaped steel;
The beam member, wherein the cover plate is continuously fillet welded to the surface of the flange except for the end portion on the side connected to the outer peripheral column.

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