JP2000144901A - Splice plate and beam joint construction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permit easy repairing during earthquake by avoiding the plasticization of a beam as a main structural member by forming a plasticized portion in a central part of a splice plate for jointing the flange of a bracket provided at a steel column to the flange of the beam. SOLUTION: At a splice plate 1 for jointing the flange of H-shaped bracket provided at the steel column to the flange of a beam, a plasticized portion 2 which is tapered from both the sides to a narrow neck portion is formed at the central part of the splice plate 1 as a rectangular beam-jointing member made of regular steel is formed. And the splice plate 1 is provided with a plurality of bolt hole 3. Thus, the cross sectional area of the center portion becomes smaller compared to a friction jointing portion for fastening bolts other than the bolt holes 3, and thus the plasticized portion 2 can restrict the strains in a range where the plastic fatigue characteristics are not disturbed so that the plasticization advances and the local concentration of strains disappear and the rupture tends to hardly occur.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beam joint member and a beam joint structure, and more particularly to a column-beam joint portion in which a beam end is prevented from being broken and damping of a structure is effectively added.

[0002]

2. Description of the Related Art In the current seismic design method for buildings, in order to stay within the elastic limit in case of small and medium-sized earthquakes, in the case of large earthquakes, the earthquake input energy is mainly absorbed by plasticizing the beam ends,
Design to prevent collapse. On the other hand, the joints (ends of beams) and joints of columns and beams can safely transmit the force acting at the time of holding horizontal strength (the maximum strength before collapse when forming the mechanism), and the plastic If it is anticipated, the design must be made so as not to break until the expected plastic deformation occurs. Therefore, the beam joint is provided so as to avoid a beam end (a range of 1/10 of the span or twice the length of the beam from the column, that is, a range of usually 1 m to 1.2 m) where plasticization is assumed. Further, when it is necessary to provide a beam joint at a place where plasticization is assumed, the safety factor α (1.2 to 1..
3) The joint is designed so as not to be broken by the force (bending and shearing) multiplied by 3).

FIG. 13 is a perspective view showing a conventional beam joint structure. In the conventional beam joint structure shown in FIG. 13, a beam 22 is rigidly joined to a joint in a strong axis direction of an H-shaped steel column 21 by welding, and a beam 22 is rigidly joined to a joint in a weak axis direction by a beam joint 23. This is the case when they are joined. FIG.
It is a perspective view which shows another conventional beam joint part structure shown by 9176 gazette. Another conventional beam joint structure shown in FIG. 14 is an example in which the beam end is devised so that the beam end is not broken. A connection 27 formed at the end of an H-shaped steel beam 26 is welded with a weld 28. Connected to the box-shaped column 25 by bolts 29, one of the flange members 26a and 26b of the H-shaped steel beam 26 has an uneven taper, and concentrates damage on a portion where the width is reduced, and stresses the beam end. To some extent.

FIG. 15 is a perspective view showing another conventional beam joint structure disclosed in Japanese Patent Application Laid-Open No. 6-341246. In another conventional beam joint structure shown in FIG. 15, a part having a large bending moment at the beam end is formed by superimposing a high-strength material and a low-strength material using ultra-soft steel at the beam end. In the example, an opening 34 or 35 is provided in the low-yield stress steel 33, and the outer peripheral portion and the opening 34 or 35 of the low-yield stress steel 33 are welded to the structural material 36 to form the low-yield stress steel 33 and the structural material 36. Are combined to form a composite steel material, and the composite structural material is used for a joint between the column 31 and the beam 32 and the like. In addition to the above, examples of using ultra-mild steel at the beam end are disclosed in JP-A-3-223383 and Reference 1 “Experimental research on hysteretic energy absorption characteristics of steel structural frames with ultra-low yield point steel (p1441-p144).
3) "-Summary of the Architectural Institute of Japan Annual Meeting (Hokuriku),
[Issued August 1992]].

FIG. 16 is a document 2 “Research on practical use of a member end mounting type hysteresis damper (p. 703 to p. 7).
06)-Summary of Architectural Institute of Japan Annual Meeting (Kanto),
[Issued March 1997]]
FIG. 6 is a perspective view showing two conventional beam joint structures. FIG.
Another conventional beam joint structure shown in FIG. 1 is that a triangular damper 42 is disposed at each corner of a column-beam joint 41 to absorb energy by plastic deformation of a low-strength material and reduce damping. Is to be granted.

[0006]

The conventional beam joint structure shown in FIG. 13 can prevent the breakage of the beam joint, but cannot prevent the breakage of the beam end where the stress becomes larger than that of the beam joint. This is because this beam end portion has scallops and the like and tends to concentrate stress. Further, depending on welding conditions, welding defects, material deterioration, and the like are likely to occur. In the Hyogoken-Nanbu Earthquake, beam end welds were frequently broken. Furthermore, even if the weld is sound and withstands a large earthquake, plasticization occurs at the beam end. As described above, when the beam end is broken or the beam end is plasticized due to the earthquake, it is necessary to replace the beam, and there has been a problem that repair requires a great deal of cost and labor.

Another conventional beam joint structure disclosed in Japanese Patent Application Laid-Open No. 10-159176 shown in FIG. 14 has a notch in a flange portion of an H-shaped steel beam as a base material.
Not only the proof strength but also the rigidity is reduced. In addition, it is uneconomical to cut and degrade the cross-sectional performance. Furthermore, since the notched portion is plastically concentrated at the time of the earthquake, the toughness and elongation capacity of the portion are required, and a high-quality steel material is required, which is uneconomical. Also, repairs after the earthquake had to be cut and rejoined in order for the beam base material to be plasticized, and there was also a problem that it was necessary to support and was difficult.

Further, another conventional beam joint structure shown in Japanese Patent Application Laid-Open No. Hei 6-341246 in FIG.
Still another conventional beam joint structure shown in Document 2 of No. 6 is an example of a type in which an energy absorbing member is provided at a beam end, and the difference in distortion between the main structure and a low-strength material or a damper is reduced. There was a drawback that it was small and could not efficiently absorb energy. Furthermore, in order to efficiently absorb energy, the one shown in Document 2 of FIG.
The distance from the beam flange of the main structure must be increased, and the size of the damper increases. In addition, it is necessary to join not only to the beam but also to the column, and there is a problem that the joining is difficult particularly when the column is a closed section material such as a square steel pipe.

SUMMARY OF THE INVENTION The present invention has been made in order to solve such problems, and a beam joint member and a beam joint structure which facilitate repairing during an earthquake by preventing plasticity of a beam as a main structural member. The purpose is to obtain.

[0010]

According to a first aspect of the present invention, there is provided a splice plate for joining a flange of a bracket provided on a steel column to a flange of a beam, and a substantially central portion of the splice plate. And a plasticized portion is formed on the substrate.

According to a second aspect of the present invention, the plasticized portion of the splice plate is formed by narrowing a substantially central portion thereof.

The plasticized portion of the splice plate according to the third aspect of the present invention has a substantially central portion formed of a steel material having a lower yield point than both side portions.

According to a fourth aspect of the present invention, there is provided a splice plate having a stiffening rib which permits plastic deformation of a plasticized portion and suppresses out-of-plane deformation.

According to a fifth aspect of the present invention, there is provided a beam joint structure wherein a flange of a beam is joined to a bracket provided on a steel column by a fixing means via a splice plate having a plasticized portion at a substantially central portion.

A splice plate having a beam joint structure according to a sixth aspect of the present invention includes a stiffening rib which allows plastic deformation of the plasticized portion and suppresses out-of-plane deformation.

According to a seventh aspect of the present invention, there is provided a beam joint structure in which an attachment plate is interposed between a splice plate and a fixing means.

According to a first aspect of the present invention, there is provided a splice plate for joining a flange of a bracket provided on a steel column and a flange of a beam, wherein a plasticized portion is formed substantially at a central portion of the splice plate. Therefore, in the conventional slice plate formed with the same cross section, when used as a beam joint member, plasticization progresses at the cross-sectional defect portion of the bolt hole, and strain is concentrated locally, so it is easy to break, If the splice plate is frequently replaced and the splice becomes plastic, the thickness of the plate becomes thinner, the axial force of the bolt decreases, and the frictional force decreases. Because the plasticized part formed in the part can keep the strain within the range that does not hinder the plastic fatigue characteristics, plasticization progresses, and the strain does not concentrate locally Ri, less likely to break, no longer is also frequent replacement of the splice plate.

In the second aspect of the present invention, the plasticized portion of the splice plate is formed by narrowing the substantially central portion thereof, so that the plasticized portion can be easily formed only by cutting the splice plate. be able to.

According to a third aspect of the present invention, the plasticized portion of the splice plate is formed of a steel material having a lower yield point than the both sides at substantially the central portion thereof. The rigidity under a constant load can be increased as compared with the one formed with the above, and the elongation ability is large, so that it is also effective as a damper.

According to a fourth aspect of the present invention, since the splice plate has stiffening ribs that allow plastic deformation of the plasticized portion and suppress out-of-plane deformation, the plasticized portion plasticizes and loses rigidity. The stiffening ribs prevent the splice plate from buckling out of plane.

According to a fifth aspect of the present invention, in the beam joint structure, a beam flange is joined to a bracket provided on a steel column by a fixing means via a splice plate having a plasticized portion at a substantially central portion. Because the plasticized part of the splice plate plasticizes before the beam that is the base material, only the splice plate needs to be replaced, and repair is easier and repair is easier than when the base material is plasticized It is economically easy.

According to the sixth aspect of the present invention, the splice plate having the beam joint structure has stiffening ribs that allow plastic deformation of the plasticized portion and suppress out-of-plane deformation.
When the plasticized portion loses rigidity due to plasticization, the stiffening ribs prevent the splice plate from buckling out of plane.

According to the seventh aspect of the present invention, since the attachment plate is interposed between the splice plate having the beam joint structure and the fixing means, local stress caused by the pressing by the fixing means is dispersed, and the plasticized portion is further plasticized. When the rigidity is lost, the splint plate prevents the splice plate from buckling out of plane.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a perspective view showing a beam joint member according to Embodiment 1 of the present invention. In the figure, 1 is a splice plate which is a rectangular beam joint member made of ordinary steel, 2 is a plasticized portion formed by tapering the center portion of the splice plate 1 from both sides to form a narrow neck, 3 is a splice plate 11 Are provided in the plurality of bolt holes. The splice plate 1 is tapered from both sides at the center and is narrowed to form a plasticized portion 2.
Is formed, the cross-sectional area of the central portion is smaller than that of the frictional joint portion that tightens the other bolts. The cross-sectional area ratio between the central portion of the splice plate 1 and the frictional joint is determined by considering the loss of the bolt hole 3 and further considering the yield ratio of the plasticized portion 2 so that plasticization does not spread to the frictional joint. It is determined. The length of the plasticized portion 2 is set in a range not exceeding 10%, particularly preferably 5%, which is the amount of distortion of the splice plate 1, in consideration of the rotation of the maximum beam.

When a slice plate, which is a conventional beam joint having the same cross-section as shown in FIG. 13 and the like, is used as a beam joint member, plasticization proceeds at a cross-sectional defect portion of a bolt hole, and local distortion occurs. Is concentrated, so it is easy to break, replacement of beam joints is frequent, and when the splice is plasticized, the thickness becomes thinner, the axial force of the bolt decreases, the frictional force decreases, and the bolt slips. There was a problem. On the other hand, in the splice plate 1 which is the beam joint member according to the first embodiment of the present invention, the plasticized portion 2 formed by giving a taper to the center portion and having a narrow neck does not disturb the plastic fatigue characteristics. Since the plasticization can be suppressed within the range, plasticization progresses, distortion does not concentrate locally, breakage becomes difficult, and replacement of the splice plate 1 becomes less frequent.

Embodiment 2 FIG. FIG. 2 shows Embodiment 2 of the present invention.
It is a perspective view which shows the beam joint member of FIG. In the figure, 1 is a splice plate which is a rectangular beam joint member made of ordinary steel, 3 is a plurality of bolt holes provided in the splice plate 1, and 4 is a low yield point steel formed at a central portion of the splice plate 1. It is a plasticized part. As the low yield point steel forming the plasticized portion 4, a low-strength steel material, for example, L
Y100, LY160, LY235 and the like are used.
In this case, a portion other than the central portion of the splice plate 1 is formed of ordinary steel, the central portion serving as the plasticized portion 4 is formed of low yield point steel, and the two are joined by welding or the like.

Similar to the beam joint member of the first embodiment, the cross-sectional area ratio between the central portion, which is the plasticized portion 4 made of the low yield point steel, of the splice plate 1 and the frictional joint is also determined. Is determined so that the plasticization does not spread to the frictional joint in consideration of the yield ratio of the plasticized portion 4 and the yield ratio. In the case of the beam joint member according to the second embodiment, the rigidity of the joint member can be increased because the cross-sectional area ratio between the central portion and the friction joint can be increased. Plasticizing part 4
Is set to a range not exceeding 20%, preferably 10%, which is the distortion amount of the splice plate 1, in consideration of the rotation of the maximum beam. (The uniform elongation is 20% for ordinary steel and 4 for low yield steel.
(Because it is about 0%, it is desirable not to exceed this 1/2, and to take into account plastic fatigue, it is more preferable that it be 1/2.)

In the splice plate 1 which is the beam joint member according to the second embodiment of the present invention, the plasticized portion 4 formed of a low yield point steel at the center portion suppresses the strain to a range that does not hinder the plastic fatigue characteristics. As a result, plasticization progressed, strain did not concentrate locally, it became difficult to break, and the splice plate 1 was replaced less frequently. Further, the beam joint member according to the second embodiment of the present invention includes:
The rigidity under a constant load can be increased as compared with the first embodiment in which the plasticized portion 2 having a tapered substantially central portion and a slender neck is formed, and since it has a large elongation ability, it can also be used as a damper. It is valid. The plasticized portion 4 of the beam joint member according to the second embodiment has a central portion formed of a low yield point steel. However, when the central portion is formed of a steel material having a lower yield point than both side portions, the present invention is also applicable. It goes without saying that the invention is applied.

FIG. 3 shows a modified example of the beam joint member according to the second embodiment of the present invention. In this modified example, a plasticized portion 4 formed of a low-yield-point steel at the center of a splice plate 1 is formed.
Are wider than the widths at both ends of the splice plate 1. FIG. 4 shows another modification of the beam joint member according to the second embodiment of the present invention. In this modified example, the width of the plasticized portion 4 formed of the low yield point steel at the center of the splice plate 1 is narrower than the width of both ends of the splice plate 1. Each modified example has the same operation and effect as the beam joint member according to the second embodiment of the present invention.

Embodiment 3 FIG. 5 shows Embodiment 3 of the present invention.
It is a perspective view which shows the beam joint member of FIG. Embodiment 3
The splice plate 1 has two stiffening ribs 5 at the center in the width direction on one surface thereof, which allow plastic deformation of the plasticized portion 2 having a slender neck and suppress out-of-plane deformation. These two stiffening ribs 5 are arranged at intervals so as to leave a gap in the central portion of the splice plate 1. This gap allows the expansion and contraction of the plasticized portion 2 of the splice plate 1 to be absorbed by the rotation of the beam joint.

The two stiffening ribs 5 prevent the splice plate 1 from buckling out of plane when the plasticized portion 2 having a slender neck is plasticized and loses rigidity. In the third embodiment, two stiffening ribs 5 are provided. However, one stiffening rib 5 may be provided, and the provided position is not limited. Further, the splice plate 1 having the stiffening ribs 5 has the plasticized portion 2 having a slender neck. However, the splice plate 1 may have the plasticized portion 4 formed of a low yield point steel. Of course.

Embodiment 4 FIG. FIG. 6 shows Embodiment 4 of the present invention.
It is a perspective view which shows the beam joint member of FIG. Embodiment 4
In this embodiment, two attachment plates 6 are applied to a splice plate 1 having a plasticized portion 2 having a slender neck. Reference numeral 7 denotes a plurality of bolt holes provided in the attachment plate 6.
As will be described later, by attaching an attachment plate 6 between the splice plate 1 and a bolt serving as a fixing means, local stress caused by holding down the bolt is dispersed by the attachment plate 6, and the plasticized portion 2 is further plasticized to be rigid. Plate 6 when you lose
Suppresses the out-of-plane buckling of the splice plate 1. Also,
The two attachment plates 6 are arranged so that there is a gap at the center of the splice plate 1. This gap allows the expansion and contraction of the plasticized portion 2 of the splice plate 1 to be absorbed by the rotation of the beam joint. In the fourth embodiment, the splice plate 1 has the plasticized portion 2 having a slender neck. However, it is a matter of course that the splice plate 1 may have the plasticized portion 4 formed of a low yield point steel. .

Embodiment 5 FIG. FIG. 7 is a sectional view showing a beam joint structure according to the fifth embodiment of the present invention. In the fifth embodiment, the upper and lower flanges 12a and 11b of the H-shaped bracket 11 joined to the steel column 10
a and 12b are joined by a bolt 13 and a nut 14 as fixing means via a splice plate 1 having a plasticized portion 2 or 4 formed at the center. Further, a web portion 11c of the H-shaped bracket 11 and a web 12c of the beam 12 are connected by a bolt 13 and a nut 14 via a connecting plate 15. At this time, the H-shaped bracket 11
And upper and lower flange portions 11a, 11b and web portion 11c of the beam 12 and upper and lower flange portions 12a, 12b and web portion 12c of the beam 12.
There is a gap between them. This gap allows the expansion and contraction of the plasticized portion 2 of the splice plate 1 to be absorbed by the rotation of the beam joint.

Fifth Embodiment of the Present Invention Having the Structure
In the beam joint structure described above, the upper and lower flange portions 11a and 11b of the H-shaped bracket 11 provided on the steel column 10 are connected to the upper and lower flanges 12a and 12b of the beam 12 via the splice plate 1 having the plasticized portion 2 or 4 at the center. Therefore, in the event of a large earthquake, the plasticized portion 2 or 4 of the splice plate 1 plasticizes prior to the beam 12 as the base material during a large earthquake. Therefore, only the spliced plate 1 that has been plasticized needs to be replaced, and as compared with the case where the base material beam 12 is plasticized, no support work is required, repair is easy, and it is economically easy.

Embodiment 6 FIG. FIG. 8 shows Embodiment 6 of the present invention.
It is sectional drawing which shows the beam joint structure of FIG. Embodiment 6
The difference from the fifth embodiment is that the splice plate 1 having the stiffening ribs 5 is used, and the upper and lower flange portions 11a and 11b of the H-shaped bracket 11 and the upper and lower flanges 12a and 12b of the beam 12 are respectively provided. That is, the two splice plates 1 were joined together. Other configurations are the same as in the fifth embodiment. Embodiment 6
Similarly to the fifth embodiment, in the case of a large earthquake, the plasticized portion 2 or 4 of the splice plate 1 plasticizes prior to the beam serving as the base material, and in this case, the plasticized splice plate 1 It is only necessary to replace only the beam 12 of the base material.
It does not require any support work, is easier to repair, and is economically easier than plasticizing. Also, by using two splice plates 1, the upper and lower flange portions 11a and 11b of the H-shaped bracket 11 and the upper and lower flanges 12a of the beam 12,
The rigidity of the connection with the splice plate 12b is increased, and each splice plate 1 is provided with the stiffening rib 5, so that when the plasticized portion 2 or 4 becomes plastic and loses rigidity, the splice plate 1 is prevented from buckling out of plane. I do.

Embodiment 7 FIG. 9 is a sectional view showing a beam joint structure according to Embodiment 7 of the present invention. The difference between the seventh embodiment and the fifth embodiment is that two splice plates 11 are used for each of the upper and lower flange portions of the H-shaped bracket 20 and the upper and lower flanges of the beam. And a pair of attachment plates interposed between the bolts. Other configurations are the same as in the fifth embodiment. Similarly to the fifth embodiment, the beam joint structure according to the seventh embodiment also includes a beam 12 in which the plasticized portion 2 or 4 of the splice plate 1 is a base material during a large earthquake.
In this case, only the spliced plate 1 that has been plasticized need be replaced. In comparison with the case where the base material beam 12 is plasticized, no support work is required, and repair is easy and economical. It is easy. Further, by using two splice plates 1, the flange portion 1 of the H-shaped bracket 11 can be formed.
The rigidity of the connection between 1a, 11b and the upper and lower flanges 12a, 12b of the beam 12 is increased. Further, a pair of attachment plates 6 are provided between the splice plate 1 and the bolts 13 serving as fixing means.
, The local stress caused by holding down the bolt 13 is dispersed by the attachment plate 6, and when the plasticized portion 2 is plasticized and loses rigidity, the attachment plate 6 prevents the splice plate 1 from buckling out of plane. Suppress.

Embodiment 8 FIG. FIG. 10 is a sectional view showing a beam joint structure according to Embodiment 8 of the present invention. The difference between the eighth embodiment and the fifth embodiment is that two splice plates 1 are used for the upper and lower flange portions 11a and 11b of the H-shaped bracket 11 and the upper and lower flanges 12a and 12b of the beam 12, respectively. Further, the splice plate 1 located outside the H-shaped bracket 11 and the beam 12 is provided with a stiffening rib 5, and the H-shaped bracket 1
1 and the splice plate 1 located inside the beam 12, the splice plate 1 and the bolt 1
3 with a pair of attachment plates 6 interposed therebetween. Other configurations are the same as in the fifth embodiment.

The beam joint structure according to the eighth embodiment also has a splice plate 1
The plasticized portion 2 or 4 plasticizes prior to the beam 12 as the base material, in which case only the spliced plate 1 that has been plasticized need be replaced, compared to the case where the beam 12 of the base material is plasticized. It does not require any support and is easy to repair and economically easy. Also, by using two splice plates 1, the upper and lower flange portions 11a,
The rigidity of the joint between the upper flange 1b and the upper and lower flanges 12a and 12b of the beam 12 is increased. Further, the eighth embodiment has a better workability than the sixth and seventh embodiments and is realistic.

In the beam joint structure according to the eighth embodiment shown in FIG. 10, when the plasticized portion 2 of the splice plate 1 is a LY235 low-yield point steel having a thickness of 12 mm and a cross-sectional area ratio of 07,
Referring to the load-displacement relationship between the column and the beam, which is the test result shown in FIG. 12, regarding the cross-shaped test piece of the column and the beam in FIG. 11, the deformation with respect to the load is small as indicated by the solid line. Irrespective of the proof stress, the plasticized portion 2 of the splice plate 1 yielded below the plastic proof stress of the beam 12, and the plasticization of the beam could be prevented. In the case of the beam joint structure according to the fifth embodiment shown in FIG. 7, when the plasticized portion 2 of the splice plate 1 is a LY235 low-yield-point steel having a thickness of 12 mm and a cross-sectional area ratio of 07,
Referring to the diagram showing the load-displacement relationship between the column and the beam, which is the test result shown in FIG. 12, for the cruciform test piece of the column and the beam in FIG. Out-of-plane buckling of the plasticized portion 2 of the splice 1 occurs in the vicinity, causing a decrease in proof stress, and it is necessary to replace the splice plate 1 on which the plasticized portion 2 is formed. In the case of the conventional beam joint structure, in the case of a splice plate formed of ordinary ordinary steel, the proof stress is similar to that of the fifth embodiment,
The bolt slipped near the maximum deformation, and the splice plate was broken at the third repetition.

[0040]

As described above, according to the first aspect of the present invention, there is provided a splice plate for joining a flange of a bracket provided on a steel column and a flange of a beam, wherein the splice plate is provided at a substantially central portion of the splice plate. Since the plasticized part is formed, in the conventional slice plate formed with the same cross section, when used as a beam joint member, plasticization progresses at the cross-sectional defect of the bolt hole, and strain concentrates locally Therefore, it is easy to break, the splice plate is frequently replaced, and when the splice is plasticized, the thickness of the plate becomes thinner, the axial force of the bolt decreases, the frictional force decreases, and the problem of slipping the bolt occurs. On the other hand, the plasticized part formed in the substantially central part can suppress the strain to a range that does not interfere with the plastic fatigue characteristics, so plasticization progresses and strain concentrates locally No longer with, less likely to break, there is an effect that replacement of the splice plate also become less frequent.

According to the second aspect of the present invention, the plasticized portion of the splice plate is formed by narrowing the substantially central portion thereof, so that the plasticized portion can be easily formed only by cutting the splice plate. There is an effect that can be.

According to the third aspect of the present invention, since the plasticized portion of the splice plate is formed of a steel material having a lower yield point at the substantially central portion than at both sides, the plasticized portion having a narrow neck at the substantially central portion is formed. The rigidity under a constant load can be increased as compared with the one in which the portion is formed, and the elongation ability is large, so that it is effective as a damper.

According to the fourth aspect of the present invention, since the splice plate is provided with the stiffening ribs that allow the plastic deformation of the plasticizing portion and suppress the out-of-plane deformation, the plasticizing portion is plasticized to increase the rigidity. When lost, the stiffening ribs have the effect of suppressing the splice plate from buckling out of plane.

According to the fifth aspect of the present invention, the beam joint structure has a structure in which the flange of the beam is joined to the bracket provided on the steel column by the fixing means via the splice plate having the plasticized portion at the substantially central portion. Since the plasticized portion of the splice plate plasticizes before the beam as the base material, only the splice plate needs to be replaced, and there is no need for support and repair compared to when the base material is plasticized. The effect is that it is easy and economically easy.

According to claim 6 of the present invention, the splice plate having the beam joint structure allows plastic deformation of the plasticized portion,
In addition, since the stiffening ribs for suppressing the out-of-plane deformation are provided, there is an effect that the stiffening ribs prevent the splice plate from buckling out of the plane when the plasticized portion loses rigidity due to plasticization.

According to the seventh aspect of the present invention, since the attachment plate is interposed between the splice plate having the beam joint structure and the fixing means, the local stress caused by the pressing by the fixing means is dispersed, and the plasticized portion is formed of plastic. When the rigidity is reduced and the rigidity is lost, the splice plate has an effect of suppressing the splice plate from buckling out of plane.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a beam joint member according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a beam joint member according to a second embodiment of the present invention.

FIG. 3 is a perspective view showing a modified example of the beam joint member.

FIG. 4 is a perspective view showing another modified example of the beam joint member.

FIG. 5 is a perspective view showing a beam joint member according to a third embodiment of the present invention.

FIG. 6 is a perspective view showing a beam joint member according to a fourth embodiment of the present invention.

FIG. 7 is a sectional view showing a beam joint structure according to a fifth embodiment of the present invention.

FIG. 8 is a sectional view showing a beam joint structure according to a sixth embodiment of the present invention.

FIG. 9 is a sectional view showing a beam joint structure according to a seventh embodiment of the present invention.

FIG. 10 is a sectional view showing a beam joint structure according to an eighth embodiment of the present invention.

FIG. 11 is a schematic view showing a cruciform specimen of columns and beams.

FIG. 12 is a diagram showing a load-displacement relationship between a column and a beam in a beam joint structure.

FIG. 13 is a perspective view showing a conventional beam joint structure.

FIG. 14 is a perspective view showing another conventional beam joint structure.

FIG. 15 is a perspective view showing another conventional beam joint structure.

FIG. 16 is a perspective view showing still another conventional beam joint structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Splice plate 2 Plastic part 3 Bolt hole

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tadaaki Katayama 1-1-2 Marunouchi, Chiyoda-ku, Tokyo, Japan Inside Nihon Kokan Co., Ltd. (72) Inventor Takuya Ueki 1-2-1, Marunouchi, Chiyoda-ku, Tokyo, Japan F-term (reference) in this steel pipe Co., Ltd. 2E125 AA14 AB01 AC15 AG12 BB02 BB22 BC05 BD01 BD06 BE02 CA05 EA00 3J066 AA26 BA03 BB01 BC03 BD07 BF11 BG05

Claims (7)

[Claims] 1. A splice plate for joining a flange of a bracket provided on a steel column and a flange of a beam, wherein a spliced portion is formed at a substantially central portion of the splice plate. plate. 2. The splice plate according to claim 1, wherein the plasticized portion is formed by narrowing a substantially central portion of the splice plate. 3. The splice plate according to claim 1, wherein the plasticized portion is formed of a steel material having a lower yield point than a substantially central portion of the splice plate than both side portions. 4. The splice plate according to claim 1, wherein the splice plate includes a stiffening rib that allows plastic deformation of the plasticized portion and suppresses out-of-plane deformation. 5. A beam joint structure wherein a flange of a beam is joined to a bracket provided on a steel column by a fixing means via a splice plate having a plasticized portion at a substantially central portion. 6. The beam joint structure according to claim 5, wherein the splice plate includes a stiffening rib that allows plastic deformation of the plasticized portion and suppresses out-of-plane deformation. 7. A splicing plate interposed between the splice plate and the fixing means.
The beam joint structure described.