JPH11280150A - Earthquake resisting type column beam joint construction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an earthquake resisting column and beam construction capable of improving earthquake resistance of a building, simplifying joint construction, rationalizing welding and reducing the weight of steel frame. SOLUTION: An earthquake resisting type column and beam joint construction tries to enlarge the plastic region by setting the plastic deformation point for the base material of beam and making the joint strength as same as the strength of base metal at the plastic deformation point in a beam basically formed by a H-section steel. And for actually achieving this, the width of a flange 9 of a beam end portion 7 is enlarged in a predetermined range or enlarged toward a beam end portion by installing a stiffening plate having the same material as a roll material for base metal; also, it is considered to enlarge the width of flange 9 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 a with the width increased, or a strain stopper for flange attached only to the web is provided 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 a plastic deformation by setting a plastic deformation point on a beam base material and making the joint strength the same as the base material strength at the plastic deformation point. The present invention relates to an earthquake-resistant column / beam joint structure that increases deformation capacity and plastic strength to improve earthquake resistance, and at the same time, simplifies the joint structure, streamlines welding, and achieves a reduction in steel frame weight.

[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-jointed structure is to expand the plastic region by setting the plastic deformation point on the beam base material and making the joint strength the same as the base material strength at the plastic deformation point in a beam basically made of H-section steel. In order to achieve this concretely, the flange width at the beam end is expanded in a predetermined range or expanded toward the beam end by installing a reinforcing plate of the same material as the roll material of the base material. Also, 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. 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 a rolled H steel having a flange 5 and extends from the position of the plastic deformation point 6 set in the base material to the end 7.
Up to now, the reinforcing member 8 is welded to the flange 5. 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. . Welding methods include butt welding,
Partial penetration welding or the like is used, but butt welding has a large heat capacity and changes the quality of the steel material, making it harder and easier to crack. Therefore, it is desirable to employ partial penetration welding including welding of an end flange described later.

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 resistance at the plastic deformation point 6 set on the base material is set, and then the plastic deformation resistance of the beam end is set to the same value. Therefore,
When seismic force or the like is applied to the building, the column / beam joint and the base material of the girder with the plastic deformation point set are the same, forming a wide range of plastic deformation area, expanding the plastic deformation area. Can improve the plastic deformation capacity of columns and beams. In FIG. 1, the shape of the reinforcing member 8 is tapered so as to temporarily expand toward the end of the beam to correspond to the plastic moment. However, the shape of the reinforcing member 8 is not limited to this. Other shapes such as rectangles are naturally adopted as long as they do not deviate from the gist of the present invention that the plastic deformation strength at the plastic deformation point set in the base material and the plastic deformation strength at the beam end are set to be the same. It is possible.

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, what is different from the conventional case is that
As described above, the plastic deformation point is not applied to the joint, and since the plastic deformation resistance of the base material and that of the joint are the same,
The thickness of the steel plate at the flange portion is sufficient because a steel plate having a thickness not so different from the central flange is sufficient.

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 strength at the step 13 and the joint proof strength are set. Since it is not necessary to perform a separate operation such as welding a separately formed reinforcing material, it is possible to increase efficiency in manufacturing and reduce costs.

In the embodiment shown in FIG. 3, the end flange 9 having a large width is formed on the entire built material. As the built material, a steel plate having a flange portion having the same thickness as the central portion of the roll material is used. It is manufactured by assembling and welding as an end H-shaped 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 reinforcing portion of the flange starts from the joint portion between the roll material and the built material. Therefore, the plastic proof stress at the plastic deformation point 6 set in the base material and the plastic proof stress at the joint portion are set for the welded portions.
Regardless of the plastic proof stress, even if the problem of the reliability of the welding is at the root, in the comparison setting as the design value, it will be performed based on the same properties, and it is necessary to expand the plastic range in the expected base material. It can be said to be an effective 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. In this case, a new diaphragm 16 is 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 may be tapered as shown in FIG. 1, but if it is rectangular, it is shown in FIGS. 5 (a) and 5 (b).
It is also effective to process the end portion 18 on the plastic deformation point side as shown in FIG. In the example shown in FIG. 5 (a), a notch 19 is formed at the end portion 18 at an angle of 45 degrees, whereby the thermal stress at the time of welding is distributed over the entire reinforcing material to ensure uniform quality. be able to. 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. . The example of FIG.
In addition to 9, the end in contact with the flange 5 is machined into a circle 20 by a grinder or the like, 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. Therefore, only the movement of the flange 5 during buckling is suppressed in a state where the rigidity of the beam itself is not affected at all, so that the merit of the seismic column / beam joint structure according to the present invention is further improved.

[0015]

According to the seismic column-beam joint structure of the present invention, in a beam basically formed of an H-section steel, a plastic deformation point is set to a beam base material and a joint strength is set at a base material strength at a plastic deformation point. In order to achieve this concretely, the flange width at the end of the beam is set to a predetermined range by installing a reinforcing plate of the same material as the roll material of the base material. So that it expands toward the beam end or
Also, it is considered that the flange width is increased by using a built-in material provided at the end of the base material. In addition, it is also characterized by providing a slope on the base material side of the flange whose width has been increased, or providing a strain stop for the flange attached only to the web between the upper and lower flanges, so as to increase the plastic deformation capacity and plastic proof stress. In addition to improving the earthquake resistance, the unit price of steel frames can be reduced, and the number of steel frames for large beams and the number of shear plates and bolts can be reduced. This has the effect of avoiding the transmission of information.

[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 (9)

[Claims] 1. An earthquake-resistant column / beam joint structure for a beam formed of an H-section steel, in which a plastic deformation point is set on a beam base material and a joint strength is equal to the base material strength at the 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 seismic column / beam joint structure according to claim 1, wherein the flange width at the beam end is increased toward the beam end. 4. The seismic column / beam joint structure according to claim 2, wherein the flange width is increased by installing a reinforcing plate. 5. The seismic column-beam joint structure according to claim 2, wherein the same material is used. 6. An earthquake-resistant column / beam joint structure according to claim 2, wherein the width of the flange is increased by a built-in material. 7. The seismic column / beam joint structure according to claim 6, wherein the joint is performed at an end portion of the built material. 8. The seismic 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. 9. The seismic column / beam joint structure according to claim 1, wherein a flange is provided between the upper and lower flanges to prevent distortion of the flange attached only to the web.