JP6786224B2 - Column-beam structure with anti-vibration structure - Google Patents

Description

The present invention relates to a column-beam structure having a vibration-reducing structure against earthquake motion.

In recent years, buildings have been required to maintain a certain function and suppress damage even in the event of a large earthquake motion, and it has become an issue to suppress the building deformation angle at the time of maximum response to about 1/100. For this reason, vibration control structures and seismic isolation structures are becoming widespread, but costs, design and site restrictions for the installation of vibration control and seismic isolation devices, and vibration control and seismic isolation against unexpected disturbances. There are many issues to consider, such as safety issues due to device performance. In addition, when performing ordinary seismic design for reinforced concrete and steel-framed buildings without using these devices, it is economical and architectural to suppress the building deformation angle at the maximum response to about 1/100. It is necessary to secure a fairly large building strength that can cause major obstacles in a planned manner. This is because the yield deformation angle is about 1/150 to 1/100 in a normal structure, so that large energy absorption cannot be expected before that, and the damping effect cannot be exerted efficiently.

Patent Documents 1 and 2 are examples of techniques for obtaining a vibration damping effect by improving the structural members of an existing building. Patent Document 1 shows FIG. 10 as a beam-column joint structure of a steel structure that solves the lack of ductility of a welded portion at a beam-column joint in a steel structure, improves ductility by about 5 times on average, and enhances seismic performance. We propose the structure shown. Patent Document 2 proposes the structure shown in FIG. 11 as a vibration damping structure that can be expected to suppress excessive deformation of the steel frame structure and improve the energy absorption capacity at the time of a large earthquake.

Japanese Unexamined Patent Publication No. 8-4112 Japanese Unexamined Patent Publication No. 2003-129565

In the structure of Patent Document 1, as shown in FIG. 10, in the H-shaped steel beam (97) joined to the box column (96) by welding (91) and bolt (94), a pair of upper and lower flange plates (81) are formed. , 82) is cut out to provide a notch (80), and the range of this notch (80) is 2D or less (D: beam back). In the section (98) where the notch (80) is provided, the flange yields evenly and the plastic hinge length becomes long, so it can be expected that the ductility of the beam-column joint and the seismic resistance of the building will be improved. However, this structure is a technology devised to solve the lack of ductility of the welded part, and since the cross section of the part away from the beam end is cut out, the bending strength of the beam member itself does not have a notch. Compared to the yield strength in the case, it is only about 10 to 20% smaller, and the yield deformation angle is also smaller by that amount. For this reason, there is a problem that a large amount of energy cannot be expected to be absorbed by the time the building deformation angle reaches about 1/100 to 1/75, and the damping effect cannot be efficiently exerted.

In the vibration damping structure of Patent Document 2, as shown in FIG. 11, a plate-shaped reinforcing material (104) is provided on the beam portion near the column (101), and one end (4a) of the reinforcing material (104) is a column. The other end (4b) is fixedly connected to the beam (103) at a distance from the column. The beam (103) is made of H-section steel and has two horizontal flanges (3a, 3b) and a vertical web plate (3b) located between these flanges. (102) is a share plate. Further, the intermediate range between both ends of the reinforcing member (104) is supported by the beam (103) so as not to be constrained in the beam axial direction and to be constrained in the orthogonal direction of the beam axis. There is. When bending stress is generated in the beam during an earthquake, the column side end of the beam yields in advance, plastic deformation increases, and energy is absorbed. At this time, since the intermediate range of the reinforcing material can move in the material axial direction of the beam relative to the beam, it hardly deforms. Then, when the plastic deformation of the beam further increases, the intermediate range of the reinforcing material resists and prevents further deformation of the beam. Therefore, excessive deformation of the building can be suppressed, and at the same time, large energy absorption can be expected. However, the mechanism of these effects is complicated, and it is considered that a large amount of data is required to verify the effects, so that there is a problem in terms of practical use. In addition, a large number of loose holes are formed in the intermediate range between both ends of the reinforcing material in the axial direction of the beam material, and the beam and the reinforcing material are joined by buckling stiffening bolts (105) inserted into these loose holes. As a result, the beam flange has a cross-sectional defect and the structural details are complicated. For this reason, there are problems such as a decrease in the bending strength of the beam and an increase in cost. Further, there is a problem that the damping effect cannot be efficiently exhibited because the intermediate range of the reinforcing material does not resist unless the plastic deformation of the beam increases to some extent.

In view of the above-mentioned problems of the prior art, the present invention is not inferior in cost to the conventional seismic structure, and is restricted by the design and site conditions as compared with the conventional vibration control structure and seismic isolation structure. It is also an object of the present invention to provide a column-beam structure having a vibration-damping structure capable of absorbing a large amount of energy from a small deformation level and efficiently exerting a vibration-damping effect.

In a beam-column structure having a vibration-reducing structure for achieving the above object, a plastic hinge portion is provided at a beam end portion and / or a column end portion of a building, and the rigidity and / or yield resistance of the plastic hinge portion is the plastic hinge. A vibration-reducing structure is provided by configuring the beam end and / or the column end so as to be smaller than the rigidity and / or yield resistance other than the portion, and the plastic hinge portion yields at the plastic hinge portion. Is configured such that the deformation angle of the building starts at at least 1/150, the column and the beam are made of reinforced concrete, and are joined at a beam- column joint, and the beam end and the beam-beam joint are joined. It is characterized in that a bending crack-inducing joint is provided near the center of the beam width so that a predetermined cover thickness of the reinforcing bar can be secured at the boundary of the beam .
A beam-column structure having another vibration-reducing structure for achieving the above object is provided with a plastic hinge portion at the beam end portion and / or the column end portion of the building, and the rigidity and / or yield resistance of the plastic hinge portion is increased. A vibration-reducing structure is provided by configuring the beam end and / or the column end so as to be smaller than the rigidity and / or yield resistance other than the plastic hinge portion, and the plastic hinge portion is the plastic hinge. The yield in the section is configured so that the deformation angle of the building starts at at least 1/150, the column and the beam are made of reinforced concrete and are joined at the column-beam joint, and the column end and the beam are joined. It is characterized in that a bending crack-inducing joint is provided near the center of the column width and / or column formation so that a predetermined cover thickness of the reinforcing bar can be secured at the boundary with the joint .
A beam-column structure having another vibration-reducing structure for achieving the above object is provided with a plastic hinge portion at the beam end portion and / or the column end portion of the building, and the rigidity and / or yield resistance of the plastic hinge portion is increased. A vibration-reducing structure is provided by forming the beam end and / or the column end so as to be smaller than the rigidity and / or yield resistance other than the plastic hinge portion, and the plastic hinge portion is the plastic hinge. Yield in the section is configured such that the deformation angle of the building begins at least 1/150, the beam and the column are of steel construction, and the beam member and / or column except for the region corresponding to the plastic hinge portion. The plastic beam portion is formed by reinforcing the member with a steel plate.

According to the column-beam structure having this vibration-reducing structure, the yield at the plastic hinge portion starts at a deformation angle of at least 1/150 of the building, and the yield deformation angle is smaller than before, so that a large energy is absorbed from a small deformation level. It is possible to efficiently exert the vibration damping effect. In this way, it is possible to exhibit excellent energy absorption performance as compared with the conventional design method, and it is possible to significantly reduce the building deformation angle (response) at the time of a large earthquake. In addition, the vibration-reducing structure can be realized simply by devising the cross-sectional shape and reinforcement arrangement of the structural members, so it is comparable in cost to the conventional seismic-resistant structure and compared to the conventional vibration-damping structure and seismic isolation structure. However, it is not restricted by the design and site conditions.

In the beam-column structure having yet another vibration-reducing structure for achieving the above object, a plastic hinge portion is provided at the beam end portion and / or the column end portion of the building, and the rigidity and / or yield resistance of the plastic hinge portion is provided. A vibration-reducing structure is provided by configuring the beam end and / or the column end so that is smaller than the rigidity and / or yield resistance other than the plastic hinge portion, and the length of the plastic hinge portion is increased. The area from the beam end to 1/2 or less of the beam and / or from the column end to the column or the column width is 1/2 or less , the beam and the column are made of steel, and the area corresponding to the plastic hinge portion is defined. Except for this, the beam member and / or the column member is reinforced with a steel plate to form the plastic hinge portion .

According to the column-beam structure having this vibration-reducing structure, the length of the plastic hinge portion is reduced from the beam end to the beam formation and / or from the column end to the column formation or the column width to 1/2 or less of the yield deformation of the building. The angle becomes smaller than before, and a large amount of energy can be absorbed from a small deformation level to efficiently exert the vibration damping effect. In this way, it is possible to exhibit excellent energy absorption performance as compared with the conventional design method, and it is possible to significantly reduce the building deformation angle (response) at the time of a large earthquake. In addition, the vibration-reducing structure can be realized simply by devising the cross-sectional shape and reinforcement arrangement of the structural members, so it is comparable in cost to the conventional seismic-resistant structure and compared to the conventional vibration-damping structure and seismic isolation structure. However, it is not restricted by the design and site conditions.

In the column-beam structure having the vibration-reducing structure, the column and the beam are made of reinforced concrete and are joined at a column-beam joint, and the cross-sectional area of the main bar at the plastic hinge portion is the main bar of the portion where the plastic hinge does not occur. The plastic beam portion can be constructed by making it relatively small compared to the cross-sectional area of.

Further, the column and the beam are made of reinforced concrete and are joined at the beam-column joint so that only the beam and / or a part of the main bar of the column is fixed to the beam-column joint. , A plastic beam can be constructed.

Further, the column and the beam are made of reinforced concrete and are joined at a column-beam joint so that a predetermined cover thickness of the reinforcing bar can be secured at the boundary between the beam end and the beam-column joint . By providing a bending crack-inducing joint near the center of the beam width, it is possible to concentrate the plastic strain on the beam end, improve the energy absorption performance at the time of an earthquake, and control damage other than the beam end.

Further, the column and the beam are made of reinforced concrete and are joined at a column-beam joint so that a predetermined cover thickness of the reinforcing bar can be secured at the boundary between the column end and the column-beam joint . By providing bending crack-inducing joints near the center of the column width and / or column formation, plastic strain is concentrated on the column ends, improving energy absorption performance during an earthquake and controlling damage other than the column ends. Can be done.

Further, the beam and the column are made of steel, and the cross-sectional area of the beam member and / or the column member in the plastic hinge portion is made relatively smaller than the portion where the plastic hinge does not occur, so that the plastic hinge portion can be made. Can be configured.

Further, the beam and the column are made of steel, and the plastic hinge portion can be formed by reinforcing the beam member and / or the column member with a steel plate other than the plastic hinge portion.

According to the column-beam structure having the vibration-reducing structure of the present invention, the cost is comparable to the conventional seismic structure, and the design and site conditions are restricted as compared with the conventional vibration-damping structure and seismic isolation structure. In addition, it can absorb a large amount of energy from a small deformation level and efficiently exert a vibration damping effect.

It is a cross-sectional view (a) of a beam in the beam formation direction and the cross-sectional view (b) of a main part in the vicinity of a column-beam joint in the direction of BB in the reinforced concrete column-beam structure according to the first embodiment. It is a graph which shows roughly the history curve of the seismic force and the building deformation angle in the column-beam structure which has the vibration-reducing structure by 1st Embodiment, and the column-beam structure by the conventional general design method. It is the schematic for demonstrating the building deformation angle of FIG. It is the same cross-sectional view as FIG. 1 (b) for explaining the 1st modification of 1st Embodiment. A cross-sectional view (a) similar to FIG. 1 (b) for explaining a second modification of the first embodiment, and a cross-sectional view (b) similar to FIG. 1 (b) for explaining a third modification. It is a cross-sectional view (c) of a main part showing a column-beam joint portion between a column and a beam and a beam cross-sectional view (d) in the dd line direction for explaining still another modification. It is a side view (a) of the main part of a column and a beam for explaining the 4th modification of 1st Embodiment, and the cross-sectional view (b) of the column in the direction of line bb. It is the same cross-sectional view as FIG. 1 (b) for explaining the 2nd Embodiment. It is a cross-sectional view (a) of a beam formation direction and a cross-sectional view (b) of a main part in the vicinity of a column-beam joint in the BB-BB line direction in a steel-framed column-beam structure according to a third embodiment. A cross-sectional view (a) of a beam similar to FIG. 8 (a) for explaining a modified example of the third embodiment, a cross-sectional view (b) in the bb-bb line direction similar to FIG. 8 (b), and cc. It is sectional drawing (c) in the -cc line direction. It is a figure which shows the column-beam joint structure of the steel frame structure by patent document 1. FIG. It is a figure which shows the vibration damping structure of the steel frame structure by patent document 2.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a cross-sectional view (a) of a reinforced concrete beam according to the first embodiment in the beam forming direction and a cross-sectional view (b) of a main part in the vicinity of a column-beam joint in the BB line direction.

In the beam-column structure of FIGS. 1A and 1B, the beam 10 is made of reinforced concrete in which a plurality of main bars 11 are arranged in the beam concrete on the beam upper surface 10a side and the beam lower surface 10b side in the beam longitudinal direction. It is a thing. Each main bar 11 extends to the beam-column joint 12 and is fixed.

As shown in FIG. 1B, each main bar 11 has a main bar reduction portion 15 in which the cross-sectional area of the main bar is reduced at the beam end portion 19, and the main bar reduction portion 15 constitutes a plastic hinge portion. The main bar reduction portion 15 has a predetermined length L from the boundary 13 between the beam 10 and the column-beam joint portion 12, and this predetermined length L is the plastic hinge length L.

In FIGS. 1A and 1B, the cross-sectional area of the main bar 11 of the plastic hinge portion 15 at the beam end portion 19 of the beam 10 is relatively small as compared with the portion where the hinge is not generated, and the plastic hinge length L is a member. It is considerably shorter than the length.

The plastic hinge length L in FIGS. 1A and 1B is preferably H × 1/2 or less, where H is the beam formation. Since the plastic hinge length L is within the range of H × 1/2 or less, the yield area is shortened within a range where there is no structural problem, and the member rigidity up to the yield is hardly changed. The deformation angle can be reduced. That is, the plastic hinge portion 15 reliably yields at a building deformation angle of at least 1/150.

In addition, when the plastic hinge length L is gradually reduced within the range of H × 1/2 or less and there is no structural problem, the energy absorption capacity and the building deformation angle at the time of a large earthquake (as the yield deformation angle decreases) The effect of reducing the response) is increased, and for example, it is possible to easily reproduce the same stress state as during a medium earthquake in members other than the plastic hinge portion.

In the present embodiment, as compared with the case where the cross-sectional area of the plastic hinge portion 15 is not relatively small, the member rigidity up to the yield is almost the same and the yield deformation angle is small, so that it is excellent from the stage of small deformation. Shows energy absorption performance. That is, the vibration damping effect can be efficiently exhibited. Therefore, a building structure having this performance is called a vibration-reducing structure. In the vibration-damping structure, an efficient vibration-damping effect can be obtained simply by devising the cross-sectional shape and reinforcement arrangement of the structural members, so the cost is comparable to that of a normal seismic structure, and the vibration-damping structure and seismic isolation structure Compared to, it is not restricted by the design and site conditions.

In general, the damping structure does not exert the damping effect by dampers unless the building is deformed to some extent, so the shaking of the building during a large earthquake is not so different from that of a normal building (seismic structure), but the pillars. Damage to structural members such as beams is reduced. On the other hand, in a vibration-reducing structure like this embodiment, the yield deformation angle of a building can be controlled by devising structural members such as columns and beams, so that in the event of a large earthquake, compared to a normal building (seismic structure). In addition to being able to significantly reduce the shaking of buildings in the above, damage to structural members such as columns and beams is also reduced.

FIG. 2 is a graph schematically showing the history curves of the seismic force and the building deformation angle in the column-beam structure having the vibration-reducing structure according to the present embodiment and the column-beam structure according to the conventional general design method. The column-beam structure according to the conventional general design is a structure in which the plastic hinge portion 15 as shown in FIG. 1 is not provided. FIG. 3 is a schematic view for explaining the building deformation angle of FIG.

As shown in FIG. 2, when a load is repeatedly applied to the building during a large earthquake, the beam having the vibration-reducing structure of the present embodiment yields at the plastic hinge portion provided at the beam end when there is no plastic hinge portion. It yields with a yield strength of 2/3 Qy with respect to the yield strength Qy, and deforms while drawing a history curve a. On the other hand, a beam according to a conventional general design method yields with a yield strength Qy and draws a history curve b. In the beam-column structure of the present embodiment, as shown in c of FIG. 2, the rigidity up to the yield of the member is almost the same as that of the conventional beam, so that the yield deformation angle is small. Here, assuming that the yield deformation angle corresponding to the conventional general design method is 1/150 to 1/120 and the yield strength Qy at this time is 2/3 Qy as in the present embodiment. The yield deformation angle is about 1/200. That is, the plastic hinge portion in the column-beam structure of the present embodiment is configured so that the yield deformation angle is at least 1/150. The building deformation angle θn is expressed by the following equation (1), where the height of the nth floor portion of the building is hn and the horizontal displacement of the nth floor portion during an earthquake is δn, as shown in FIG.
θn = δn / hn (n = 1, 2, 3, ...) (1)

Also relates to the equivalent damping constant h _eq as an index representing the energy absorption capacity, when calculating the equivalent damping constant h _eq of both Figures 2, h _eq 'corresponding to Column structure of this embodiment, a conventional general It is about 1.7 times larger than the h _eq of the beam according to the design method. In FIG. 2, the equivalent attenuation constants h _eq and h _eq ′ can be obtained as follows.
H _eq ´ of the present embodiment = Area of solid line surrounded by history curve a / Area of triangle surrounded by point oei Conventional h _eq = Area of broken line surrounded by history curve b / Area of triangle surrounded by point ogi

As described above, according to the present embodiment, by providing the plastic hinge portion at the beam end portion and reducing the yield deformation angle to at least 1/150, it is superior to the beam of the conventional general design method. It is possible to exhibit the energy absorption performance, and by extension, the building deformation angle (response) at the time of a large earthquake can be significantly reduced.

In the present embodiment, since the yield of the main bar 11 occurs in the reduced cross-sectional area 15, the bending strength at the time of yielding is smaller than that in the case where the cross-sectional area of the plastic hinge portion is not relatively small. However, in the column-beam structure according to the present embodiment, since the yield starts from a small deformation with a building deformation angle of at least 1/150, excellent energy absorption performance is exhibited. Therefore, as described with reference to FIG. 2, the building deformation angle (response) at the time of a large earthquake can be remarkably reduced as compared with the conventional column-beam structure, and a large energy absorption performance can be obtained. Therefore, it has high quality in terms of cost including repair of damage to structural members and maintenance of performance.

Next, first to fourth modifications of the first embodiment will be described with reference to FIGS. 4 to 6. FIG. 4 is a cross-sectional view similar to FIG. 1 (b) for explaining the first modification of the first embodiment.

In the example of FIG. 4, the cross-sectional area of the main bar of the plastic hinge portion is reduced by using a different diameter joint. A different diameter joint portion 16 is provided in the vicinity of the beam end portion 19 on the main bar 11 of the reinforced concrete beam 10. The length of the main bar 11 (the diameter is reduced) from the left end of the figure of the different diameter joint portion 16 to the boundary 13 between the beam 10 and the column-beam joint portion 12 is the plastic hinge length L. According to this example, excellent energy absorption can be achieved from a small deformation level where the building deformation angle is at least 1/150.

FIG. 5 is a cross-sectional view (a) similar to FIG. 1 (b) for explaining a second modification of the first embodiment, and a cross section similar to FIG. 1 (b) for explaining a third modification. FIG. (B) is a cross-sectional view (c) of a main part showing a column-beam joint portion between a column and a beam for explaining still another modified example, and a beam cross-sectional view (d) in the dd line direction.

In the example of FIG. 5A, in the structure of FIG. 1, a slit 17 is provided as a bending crack induction joint at the boundary 13 between the beam 10 and the beam-column joint 12. In the example of FIG. 5B, in the structure of FIG. 4, a slit 17 is provided as a bending crack induction joint at the boundary 13 between the beam 10 and the beam-column joint 12. 5 (c) and 5 (d) show a plurality of slits 17 provided at both boundaries 13 between the beam 10 and the beam-column joint 12. According to the examples of FIGS. 5A and 5B, it is possible to further improve the energy absorption performance by reducing the damage of the concrete. Further, as shown in FIGS. 5C and 5D, the slit 17 is provided in a rectangular shape or near the center of the upper and lower ends of the rectangular cross section of the beam 10 after ensuring a predetermined cover thickness of the reinforcing bar. It can be a plurality of trapezoidal slits.

FIG. 6 is a side view (a) of a main part of a column and a beam and a cross-sectional view (b) of the column in the b-b line direction for explaining a fourth modification of the first embodiment. In the example of FIGS. 6A and 6B, a slit 37 is provided as a bending crack induction joint also at the boundary 33 of the column end portion. That is, at the boundary 33 between the column 30 and the column-beam joint portion 12, a plurality of rectangular or trapezoidal slits 37 are formed near the center of each side of the rectangular cross section of the column 30 after ensuring a predetermined cover thickness of the reinforcing bar. It is provided. It is possible to further improve the energy absorption performance by reducing the damage to the concrete of the columns.

<Second Embodiment>
FIG. 7 is a cross-sectional view similar to FIG. 1 (b) for explaining the second embodiment. In the second embodiment, as shown in FIG. 7, a part of the main bar is non-fixed in the reinforced concrete beam 10. That is, the central main bar 11a of the plurality of main bars 11, 11a, 11 of the reinforced concrete beam 10 is arranged up to the boundary 13 between the beam 10 and the column-beam joint 12 and fixed to the column-beam joint 12. Instead, the main bars 11 and 11 are fixed to the beam-column joint 12. The fixing portion 18 formed by the main bars 11 and 11 at the boundary 13 constitutes the plastic hinge portion. According to this embodiment, excellent energy absorption can be achieved from a small deformation level in which the building deformation angle is at least 1/150.

In the first and second embodiments described above, an example in which a plastic hinge portion is provided at the beam end portion in a reinforced concrete column-beam structure has been described, but a similar plastic hinge portion configuration may be provided at the column end portion. And the same effect can be obtained. Further, plastic hinges may be provided on both the beam end and the column end.

<Third Embodiment>
FIG. 8 is a cross-sectional view (a) of the steel-framed beam in the beam formation direction and a cross-sectional view (b) of a main part in the vicinity of the column-beam joint in the BB-BB line direction according to the third embodiment.

In the beam-column structure of FIGS. 8A and 8B, the beam 20 is a steel structure made of H-shaped steel, and a pair of upper and lower flanges 21 and 21 located in the horizontal direction on the beam upper surface 20a side and the beam lower surface 20b side. , A web 22 located in the vertical direction connecting the pair of flanges 21 and 21.

As shown in FIG. 8B, the upper and lower flanges 21 and 21 of the beam 20 have a cross-section reduction portion 25 whose cross-sectional area is reduced at the beam end portion, and this cross-section reduction portion 25 constitutes a plastic hinge portion. The cross-section reduction portion 25 has a predetermined length L2 from the boundary 24 between the beam 20 and the column-beam joint portion 23, and this predetermined length is the plastic hinge length L. The beam 20 and the beam-column joint 23 are joined by welding, for example.

Further, in FIGS. 8A and 8B, the cross-sectional area of the flange 21 of the plastic hinge portion 25 at the beam end portion of the beam 20 is relatively small as compared with the portion where the hinge is not generated, and the plastic hinge length L is It is considerably shorter than the member length.

The plastic hinge length L in FIGS. 8A and 8B is preferably H × 1/2 or less, where H is the beam formation, as in the case of FIGS. 1A and 1B. Since the plastic hinge length L is within the range of H × 1/2 or less, the yield area is shortened within a range where there is no structural problem, and the member rigidity up to the yield is hardly changed. The deformation angle can be reduced. That is, the plastic hinge portion 25 reliably yields at a building deformation angle of at least 1/150.

In the present embodiment, as compared with the case where the cross-sectional area of the plastic hinge portion 25 is not relatively small, the member rigidity up to the yield is almost the same and the yield deformation angle is small, so that it is excellent from the stage of small deformation. Shows energy absorption performance. That is, the vibration damping effect can be efficiently exhibited. Therefore, a column-beam structure having the same vibration-reducing structure as in the cases of FIGS. 1 (a) and 1 (b) can be obtained.

Further, also in the present embodiment, when a load is repeatedly applied to the building during a large earthquake, the building is deformed while drawing the history curve a in FIG. 2 to show the same energy absorption capacity. That is, by providing a plastic hinge portion at the beam end and reducing the yield deformation angle to at least 1/150, excellent energy absorption performance is exhibited as compared with the beam (steel structure) of the conventional general design method. As a result, the building deformation angle (response) at the time of a large earthquake can be significantly reduced.

In the present embodiment, since the yield of the flange 21 occurs in the reduced cross-sectional area 25, the bending strength at the time of yielding is smaller than that in the case where the cross-sectional area of the plastic hinge portion is not relatively small. However, in the column-beam structure according to the present embodiment, since the yield starts from a small deformation with a building deformation angle of at least 1/150, excellent energy absorption performance is exhibited. Therefore, as described with reference to FIG. 2, the building deformation angle (response) at the time of a large earthquake can be remarkably reduced as compared with the conventional beam-column structure (steel structure), and a large energy absorption performance can be obtained. Therefore, it has high quality in terms of cost including repair of damage to structural members and maintenance of performance.

FIG. 9 is a cross-sectional view (a) of a beam similar to FIG. 8 (a) for explaining a modified example of the third embodiment, and a cross-sectional view (b) in the bb-bb line direction similar to FIG. 8 (b). ) And cc-cc line direction cross-sectional view (c). As shown in FIGS. 9A to 9C, in this example, in a steel beam 20 made of H-section steel, flanges 21 and 21 are reinforced with steel plates 26 and 26 except for a plastic hinge portion 27 from the beam end portion. It was done. That is, the reinforcing steel plates 26 and 26 are arranged on the upper and lower surfaces of the flanges 21 and 21 of the beam 20 made of H-shaped steel, and are attached by welding, bolts and nuts or the like. At this time, the steel plates 26 and 26 are shortened by a predetermined length L from the boundary 24 between the beam-column joint 23 and the beam 20. The portion having the predetermined length L constitutes the plastic hinge portion 27, and the predetermined length L is the plastic hinge length L. According to the present embodiment, excellent energy absorption is achieved from a small deformation level of at least 1/150 of the building deformation angle as compared with a beam having a flange thickness equal to the total plate thickness of the reinforcing steel plate 26 and the flange 21. be able to.

In the third embodiment described above, an example in which a plastic hinge portion is provided at the beam end portion in the steel-framed column-beam structure has been described, but a similar structure of the plastic hinge portion can be provided at the column end portion. , The same effect can be obtained. Further, plastic hinges may be provided on both the beam end and the column end.

Although the embodiments for carrying out the present invention have been described above, the present invention is not limited to these, and various modifications can be made within the scope of the technical idea of the present invention. For example, the configuration of the beam made of reinforced concrete in FIGS. 1 and 4 to 7 is not limited to the one shown in the drawing, and it goes without saying that the number of main bars and the like can be changed as appropriate.

According to the column-beam structure having the vibration-reducing structure of the present invention, the cost is comparable to the conventional seismic structure, and the design and site conditions are restricted as compared with the conventional vibration-damping structure and seismic isolation structure. In addition, it has a vibration-damping structure that can absorb a large amount of energy from a small deformation level and efficiently exert a vibration-damping effect, and can realize a cost-effective building structure.

10 Beams 11, 11a Main bar 12 Beam joint 13 Boundary 15 Main bar reduction part, plastic hinge part 16 Different diameter joint part 17 Slit 18 Fixing part, plastic hinge part 19 Beam end 30 Pillar 37 Slit 20 Beam 21 Flange 22 Web 23 Pillar Beam joint 24 Boundary 25 Section reduction, plastic flange 26 Reinforcing steel plate 27 Plastic flange L Plastic flange length H Beam formation

Claims (4)

Plastic hinges are provided at the beam ends and / or column ends of the building.
The vibration-reducing structure is formed by configuring the beam end and / or the column end so that the rigidity and / or yield strength of the plastic hinge portion is smaller than the rigidity and / or yield strength other than the plastic hinge portion. Provided
The plastic hinge portion is configured such that the yield at the plastic hinge portion begins at a deformation angle of at least 1/150 of the building.
The column and the beam are made of reinforced concrete and are joined at a column-beam joint .
A column-beam structure having a vibration-reducing structure in which a bending crack-inducing joint is provided near the center of the beam width so that a predetermined cover thickness of the reinforcing bar can be secured at the boundary between the beam end portion and the column-beam joint portion . Plastic hinges are provided at the beam ends and / or column ends of the building.
The vibration-reducing structure is formed by configuring the beam end and / or the column end so that the rigidity and / or yield strength of the plastic hinge portion is smaller than the rigidity and / or yield strength other than the plastic hinge portion. Provided
The plastic hinge portion is configured such that the yield at the plastic hinge portion begins at a deformation angle of at least 1/150 of the building.
The column and the beam are made of reinforced concrete and are joined at a column-beam joint.
At the boundary between the column end and the column-beam joint , it has a vibration-reducing structure in which a bending crack-inducing joint is provided near the column width and / or the center of the column formation so that a predetermined cover thickness of the reinforcing bar can be secured. Column beam structure. Plastic hinges are provided at the beam ends and / or column ends of the building.
The vibration-reducing structure is formed by configuring the beam end and / or the column end so that the rigidity and / or yield strength of the plastic hinge portion is smaller than the rigidity and / or yield strength other than the plastic hinge portion. Provided
The plastic hinge portion is configured such that the yield at the plastic hinge portion begins at a deformation angle of at least 1/150 of the building.
The beam and the column are made of steel.
A column-beam structure having a vibration-reducing structure, which constitutes the plastic hinge portion by reinforcing the beam member and / or the column member with a steel plate except for a region corresponding to the plastic hinge portion. Plastic hinges are provided at the beam ends and / or column ends of the building.
The vibration-reducing structure is formed by configuring the beam end and / or the column end so that the rigidity and / or yield strength of the plastic hinge portion is smaller than the rigidity and / or yield strength other than the plastic hinge portion. Provided
The length of the plastic hinge portion shall be 1/2 or less from the beam end to the beam formation and / or 1/2 or less from the column end to the column formation or column width.
The beam and the column are made of steel.
A column-beam structure having a vibration-reducing structure, which constitutes the plastic hinge portion by reinforcing the beam member and / or the column member with a steel plate except for a region corresponding to the plastic hinge portion.

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