JPH11280147A - Earthquake resisting type column and beam joint construction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an earthquake resisting type column-beam joint construction by improving the earthquake resistance of a building, simplifying joint construction, rationalizing welding, and reducing the weight of steel framing. SOLUTION: For an earthquake resisting type column-beam joint construction, basically in a beam formed by H-section steel, the plastic deformation point is set for the base metal of beam, and the joint strength is made larger than the strength of base metal at the plastic deformation point, and the base metal of beam is subjected to plastic deformation prior to the joint portion. Then, to actually achieve this, the width of a flange 9 at the beam end portion 7 is enlarged within a predetermined range by installing a stiffening plate with a material as same as the roll material of base metal, and also it is taken into consideration that enlargement of the width of the flange 9 is performed with a built material provided at the end portion of the base metal. In addition, a slope is provided at the base metal side of the flange 5 with the width increased, and a strain stopper is provided for the flange 5 attached only to the web 7 between the upper and lower flanges 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earthquake-resistant column / beam joint structure, and more particularly to an improvement in seismic resistance by setting a plastic deformation point on a beam base material to increase plastic deformation capacity and plastic resistance. In addition, the present invention relates to an earthquake-resistant column-beam joint structure that also simplifies the joint structure, rationalizes welding, and reduces the weight of steel frames.

[0002]

2. Description of the Related Art Looking at the situation of damage caused by a great earthquake, even buildings built with conventional seismic design, which is said to be sufficiently resistant to a great earthquake, are severely damaged. In particular, there are many cases where the column-beam joints of steel-framed buildings do not sufficiently exert their plastic deformation capacity, causing severe damage to the buildings. The main factors are
Insufficient proof stress of beam joints, brittle fracture due to stress concentration coming from the shape of the joints, etc., have been pointed out, and much has been pointed out about securing sufficient plastic deformation capacity of column / beam joints. The conventional column / beam joint is configured as shown in FIG. 8, and the joint is set at a plastic deformation point in design. Therefore,
In the girder 30, the central member 31 is formed of H steel as a roll material, and at both ends 32, in order to improve the strength of the joint,
A built material 33 separately welded at a factory or the like is integrated by welding. The proof strength of the connection part 34 is calculated as a structure in which the diaphragm provided on the column and the flange 35 of the built-in material are welded, and the proof strength is calculated only at the flange part, and the bonding strength of the web part is taken into consideration. Absent. For this reason, the flange 35 of the built material is often made of a material thicker than that of the base material. However, on the other hand, in order to complement this from the viewpoint of the reliability of the welded portion, in practice, the joining of the web portion is also carefully performed. For this reason,
A shear plate 36 is welded to the pillar, and the pillar and the beam are connected to the large beam end 32 and the shear plate 36 by a high-strength bolt 37.
It is integrated by joining with. Therefore, the unit cost of the steel frame has become high, and the number of steel frames and the number of shear plates and bolts of the girder members have also increased, causing the transmission of bending stress.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to improve the seismic resistance of a building. In addition, the present invention aims to improve the seismic resistance of a building. It is intended to provide a beam joint structure.

[0004]

According to the present invention, there is provided an earthquake-resistant column according to the present invention.
The beam joint structure is basically a beam formed of H-section steel, in which the plastic deformation point is set on the beam base material, the joint strength is made larger than the base material strength at the plastic deformation point, and the beam joint structure is preceded. The beam base material is plastically deformed.To achieve this concretely, the flange width at the beam end is increased within a predetermined range by installing a reinforcing plate of the same material as the base material roll material. ,or,
It is considered that the flange width is increased by using a built-in material provided at the end of the base material. Further, the present invention is characterized in that an inclined flange is provided on the base material side of the flange having an increased width, and a flange is provided between the upper and lower flanges to prevent distortion of the flange provided only on the web.

[0005]

FIG. 1 shows an earthquake-resistant column according to the present invention.
It is the top view and side view for demonstrating a beam joining structure. In the figure, 1 is a column of CFT and 2 is a girder. A diaphragm 3 and a shear plate 4 are attached to the column 1. The girder 2 is H steel of a roll material having a flange 5, and a reinforcing member 8 is welded to the flange 5 from a position of a plastic deformation point 6 set in the base material to an end 7 of the girder. The attachment of the reinforcing member 8 can be performed at any time and there is no particular limitation. However, from the viewpoint of product accuracy in consideration of thermal stress due to welding, welding at a well-managed factory is recommended. . As a welding method, butt welding, partial penetration welding, etc. are used. Adoption is desirable.

The pillar 1 and the girder 2 are integrated by welding the diaphragm 3 of the pillar and the end flange 9 having a wide width and the high-strength bolt connection 10 between the shear plate 4 and the beam web. The plastic strength at the mouth is determined by the end flange 9
It is designed with only the joints. As a result, the high-strength bolted joint 10 between the shear plate 4 and the beam web is sufficiently simple enough to maintain the mutual connection relationship, and thus is configured very simply as compared with the conventional jointed structure.

For the strength of the joint, the plastic deformation strength at the beam end is set in a state corresponding to the gradient of the plastic moment after setting the plastic strength at the plastic deformation point 6 set on the base material. Therefore, as a result, the value is set to be larger than the value of the plastic proof stress at the plastic deformation point 6, which is 1.2 times in the present embodiment. This value can be arbitrarily changed depending on the shape of the beam and the set position of the plastic deformation point, but it is necessary to set it to a value exceeding at least 1.0 in order to precede plastic deformation in the base material. Therefore, when seismic force or the like is applied to the building, plastic deformation will occur in the base material of the girder where the plastic deformation point has been set before the column / beam connection. Insufficient proof stress of the part, brittle fracture due to stress concentration resulting from the shape of the joint part, etc. can be prevented beforehand.

FIGS. 2 and 3 are plan views of a girder formed by joining ends 12 of a built-in material to both ends of a center portion 11 of a roll material in the same manner as a conventional girder, and other portions are the same as those in FIG. It is. In the embodiment shown in FIG. 2, the end flange 9 having the above-mentioned wide width is formed at the end 12 of the built material, and the steel plate of the flange is cut with a step 13 in advance when the built material is processed. It is manufactured by assembling and welding what has been done. However, the difference from the conventional case is that the plastic deformation point is not at the joint as described above, so the steel plate thickness of the flange portion is sufficient with a steel plate thickness not so different from the central flange. is there.

Since the plastic deformation point 6 in the case of FIG. 2 is naturally formed in the range of the built material having the step 13, the proof stress at the step 13 and the joint proof strength are determined by the roll material. A design with a considerably higher numerical value than the form of FIG. 1 that has been formed is allowed. Therefore, there is no need to perform a separate work such as welding a separately formed reinforcing material,
Manufacturing efficiency and cost reductions are possible.

In the embodiment shown in FIG. 3, the end flange 9 having a large width is formed on the entire built material. The end material is formed by using a steel plate having a flange portion slightly thicker than the center of the roll material. It is manufactured by assembling and welding as the H-section steel 14. Since the girder is formed by joining end portions H of the built-in material to both ends of the center portion 11 of the roll material, the step portion of the flange becomes a joining portion between the roll material and the built material.
Therefore, the proof stress at the plastic deformation point 6 set on the base material and the plastic proof stress at the joint portion are set for the welded portions. All plastic proof stresses are based on the same properties in the comparison setting as design values, even if the reliability of the welding is at the root, and are effective for the expected plastic deformation in the expected base material. It can be said that it is a form.

FIGS. 4 (a) and 4 (b) are a plan view and a side view showing another form of flange reinforcement. In the above embodiment, in order to set the plastic deformation point in the base material portion of the beam and to make the plastic strength of the column / beam joint higher than the value of the base material portion in accordance with the plastic moment gradient, the flange at the beam end is used. We have responded by reinforcing it to increase its width. This basically means to increase the cross-sectional area of the flange at the joint, so that an auxiliary flange 15 is provided at the end of the beam 2 in parallel with the flange 5 as shown in FIG.
Weight to substantially increase the cross-sectional area. At this time, a stiffener 16 is newly provided also on the column side so that the auxiliary flange 15 can be welded and joined.

The reinforcing member 8 is welded 17 to the flange 5 and its shape can be considered to be rectangular as shown in FIG. 1, but it is plastically deformed as shown in FIGS. 5 (a) and 5 (b). It is also effective to machine the end 18 on the point side. FIG.
In the example shown in (a), the end portion 18 is cut at the cutout surface 1 at an angle of 45 degrees.
The thermal stress at the time of welding is distributed over the entire reinforcing material, and uniform quality can be secured. In FIG. 5A, the shape of the cutout surface 19 is displayed as a straight surface, but the shape is not limited to this shape, and may be a cutout shape having a predetermined curvature. . In the example shown in FIG. 5B, the end in contact with the flange 5 in addition to the cutout surface 19 is formed into a circle 20 by a grinder, which is effective in dispersing the stress concentrated on the end. According to experiments, it has been confirmed that when a stress is applied to the beam by these workings, it is possible to prevent the occurrence of cracks in the flange 5 at the weld end.

FIG. 6 is a side view for explaining a flange reinforcing member attached to a beam having an earthquake-resistant column / beam joint structure according to the present invention, and FIG. 7 is a sectional view taken along the line II in FIG. As described above, since the seismic column / beam joint structure according to the present invention sets the plastic deformation point preceding the beam base material, a greater stress is applied to the flange at the center than the conventional beam. Become. For this reason, a phenomenon occurs in which the flange is partially distorted and buckled.

Therefore, it is effective to provide a flange reinforcing member 21 for suppressing the buckling of the flange on the beam base material at the center. The attached state of the flange reinforcing member 21 is shown in FIG.
As is apparent from the cross-sectional view of the beam 2 shown in FIG. 1, the flange reinforcing member 21 is attached to the web portion 22 of the beam by welding 23, and is not joined to the upper and lower flanges 5. Accordingly, only the movement of the flange 5 during buckling is suppressed without any influence on the rigidity of the beam itself, so that the advantages of the earthquake-resistant column / beam joint structure according to the present invention are further improved.

[0015]

The seismic column-beam joint structure according to the present invention basically sets the plastic deformation point on the beam base material, makes the joint strength larger than the base material strength at the plastic deformation point, and precedes the joint. In order to achieve this concretely, the width of the flange at the end of the beam is expanded within a predetermined range by installing a reinforcing plate of the same material as the roll material of the base material. And
In addition, it is considered that the width of the flange is increased by using a built-in material provided at the end of the base material. Since the attached flange has a strain stop, the plastic deformation capacity and the plastic proof strength can be increased to improve the seismic resistance, and the unit cost of steel can be reduced. Thus, the number of shear plates and bolts can be reduced, and as a result, the effect of avoiding the transmission of stress at the column / beam joint can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view and a side view showing an earthquake-resistant column / beam joint structure according to the present invention.

FIG. 2 is a plan view showing another example of the earthquake-resistant column / beam joint structure according to the present invention.

FIG. 3 is a plan view showing another example of the earthquake-resistant column / beam joint structure according to the present invention.

FIG. 4 is a plan view and a side view showing another example of the earthquake-resistant column / beam joint structure according to the present invention.

FIG. 5 is a plan view showing processing of a reinforcing material.

FIG. 6 is a side view of an earthquake-resistant column / beam joint structure using a flange reinforcing material.

FIG. 7 is a sectional view of a beam to which a flange reinforcing material is applied.

FIG. 8 is a plan view and a side view of a conventional beam-column joint structure.

[Explanation of symbols]

1 pillar 16
Diaphragm 2 Large beam 17
Welding 3 Diaphragm 18
Plastic deformation point side end 4 Shear plate 19
Notch 5 Flange 20
Circular cutting 6 Plastic deformation point 21
Flange reinforcement 7 End 22
Web part of beam 8 Reinforcement 30
Giant beam 9 End flange 31
Central member 10 High strength bolt connection 32
Beam end 11 Central part 33
Built material 12 Built material end 34
Connection 13 Step 35
Built-in flange 14 H-section steel 36
Shear plate 15 Auxiliary flange 37
High strength bolt

Claims (8)

[Claims] 1. A seismic column-beam joint structure in which a beam formed of an H-section steel is set to have a plastic deformation point at a beam base material and a joint strength is larger than a base material strength at a plastic deformation point. 2. The seismic column / beam joint structure according to claim 1, wherein the flange width at the beam end is enlarged within a predetermined range. 3. The joint structure of claim 2, wherein the width of the flange is increased by installing a reinforcing plate. 4. The seismic column / beam joint structure according to claim 2, wherein the same material is used. 5. The seismic column / beam joint structure according to claim 2, wherein the width of the flange is increased by a built-in material. 6. The seismic column / beam joint structure according to claim 5, wherein the joint is carried out at an end portion of the built material. 7. An earthquake-resistant column / beam joint structure according to claim 1, wherein an inclination is provided on a base material side of the flange having an increased width. 8. The earthquake-resistant column / beam joint structure according to claim 1, wherein a strain stop for a flange attached only to the web is provided between the upper and lower flanges.