Column-beam joint structure

Abstract

To provide a column-beam joint structure that can suppress increase in construction costs of buildings while giving concrete forming columns bearing force to withstand the force from a beam at a column-beam joint.SOLUTION: A column-beam joint 13 of a building is a point where a column 11 intersects with a point where steel beams 12 intersect with each other. The column-beam joint 13 is surrounded by a blocking plate 15 placed at a portion where it is sandwiched between the intersecting beams 12. First concrete 21 is used as concrete forming the column 11. The inside of a portion surrounded by the blocking plate 15 at the column-beam joint 13 is filled with second concrete 22, which has a higher strength than the first concrete 21. The second concrete 22 protrudes toward at least one of the column 11 located above the column-beam joint 13 and the column 11 located below the column-beam joint 13, thereby becoming a part of the concrete forming the column 11 on the protruding side.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a beam-column joint structure. [Background technology]

[0002] When a building is constructed using the RC column and S beam construction method (RCS construction method) or the like, a column-beam joint is provided in the building where the steel beams intersect with the columns. As shown in Patent Document 1, such a column-beam joint is surrounded by a closing plate that is placed in the part sandwiched between the intersecting beams. The inside of the part of the column-beam joint surrounded by the closing plate is filled with concrete. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-106108 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned building, the portion of the column-beam joint surrounded by the blocking plate is filled with concrete, and the beam of the column-beam joint passes through the concrete. Since the beam is in contact with the concrete that forms the column, the concrete is subjected to upward or downward forces from the beam. Therefore, the concrete is required to have bearing strength, which is the durability when subjected to the force from the beam. However, if the entire column were made of high-strength concrete with the intention of ensuring the bearing strength required of the concrete, the cost of building would increase by the amount of such high-strength, expensive concrete used. [Means for solving the problem]

[0005] The means for solving the above problems and their effects will be described below. The column-beam joint structure that solves the above problem is applied to a column-beam joint where a reinforced concrete column also intersects with a steel-framed beam. The column-beam joint is surrounded by a blocking plate that is placed in the area sandwiched between the intersecting beams. A first concrete is used as the concrete that forms the column. The inside of the area surrounded by the blocking plate in the column-beam joint is filled with a second concrete that is stronger than the first concrete. The second concrete protrudes toward at least one of the column located above the column-beam joint and the column located below the column-beam joint, thereby becoming part of the concrete that forms the column on the protruding side.

[0006] According to the above configuration, for at least one of the upper and lower columns of the column-beam joint, the concrete forming the column at the portion in contact with the beam of the column-beam joint is the second concrete, and the other portion is the first concrete. As a result, when a force from the beam acts on the column, the force is received by the concrete forming the portion of the column in contact with the beam of the column-beam joint, i.e., the second concrete having a higher strength than the first concrete. For this reason, the concrete forming the column can have a bearing capacity to receive the force. In addition, the first concrete having a lower strength than the second concrete is used as the concrete forming the column in the portion of the column other than the portion in contact with the beam of the column-beam joint. As a result, the amount of the second concrete used as the concrete forming the column can be reduced, thereby suppressing the increase in the cost of building.

[0007] In the above-mentioned beam-column joint structure, the second concrete protrudes toward both the column located above the beam-column joint and the column located below the beam-column joint. According to the above configuration, for both the upper and lower columns of the column-beam joint, the concrete forming the columns at the portion in contact with the beam of the column-beam joint is the second concrete, and the other portions are the first concrete. Therefore, when an upward force from the beam acts on the column located above the column-beam joint, the second concrete forming the portion of the column in contact with the beam of the column-beam joint bears the force. Also, when a downward force from the beam acts on the column located below the column-beam joint, the second concrete forming the portion of the column in contact with the beam of the column-beam joint bears the force. As a result, the concrete forming the column located above the column-beam joint and the concrete forming the column located below the column-beam joint can be provided with the bearing strength to bear the force.

[0008] In the above-mentioned column-beam joint structure, the protrusion amount H1 of the part of the second concrete protruding from the part surrounded by the closing plate of the column-beam joint toward the column located above the column-beam joint is determined as follows. That is, when a straight line L1 is determined that extends from the edge in the width direction of the top surface of the beam located at the column-beam joint toward the upper side and the outer side of the beam in the width direction to the side surface of the column located above the column-beam joint, and the distance from the intersection point of the straight line L1 and the side surface to the height position of the top surface of the beam is X1, the protrusion amount H1 is set to be equal to or less than the distance X1. Also, the protrusion amount H2 of the part of the second concrete protruding from the part surrounded by the closing plate of the column-beam joint toward the column located below the column-beam joint is determined as follows. In other words, a straight line L2 is defined extending downward and outward in the width direction from the width edge of the underside of the beam located at the column-beam joint to the side surface of the column located below the column-beam joint, and the distance from the intersection of the straight line L2 with the side surface to the height position of the underside of the beam is defined as X2, and the above-mentioned protrusion amount H2 is set to be less than or equal to the distance X2.

[0009] According to the above configuration, when an upward force from a beam acts on a column located above the beam-column joint, the force is received by the second concrete forming the portion of the column that contacts the beam of the beam-column joint. The stress in the second concrete based on the action of the force is generated so as to spread toward the portion of the column formed by the first concrete. This increases the area of ​​the first concrete of the column that receives the stress from the second concrete. Although there is an upper limit to such an increase in area, the increase in area is kept below the upper limit by setting the overhang amount H1 to the distance X1 or less. This makes it possible to prevent the second concrete from being used in an excessively large amount as the concrete forming the column.

[0010] Furthermore, when a downward force from a beam acts on a column located below the beam-column joint, the force is received by the second concrete that forms the portion of the column that contacts the beam of the beam-column joint. The stress in the second concrete based on the action of the force is generated so as to spread toward the portion of the column that is formed by the first concrete. This causes the area of ​​the first concrete of the column that receives the stress from the second concrete to be expanded. Although there is an upper limit to this expansion of area, the expansion of the area is kept below the upper limit by setting the overhang amount H2 to be equal to or less than the distance X2. This makes it possible to prevent the second concrete from being used in an excessively large amount as the concrete that forms the column.

[0011] In the above-mentioned beam-column joint structure, the inclination angle A1 of the straight line L1 relative to the upper surface of the beam is considered to be a value in the range of 45° or more and less than 90°, and the inclination angle A2 of the straight line L2 relative to the lower surface of the beam is considered to be a value in the range of 45° or more and less than 90°.

[0012] When an upward force from a beam acts on a column located above a beam-column joint, a stress based on the force is generated in the second concrete that forms the part of the column that contacts the beam at the beam-column joint, spreading toward the part of the column formed by the first concrete. It is estimated that the stress acting on the second concrete spreads at an angle of 45° to the top surface of the beam toward the part of the column formed by the first concrete.

[0013] Furthermore, when a downward force from a beam acts on a column located below a beam-column joint, a stress based on the force is generated in the second concrete that forms the portion of the column that contacts the beam at the beam-column joint, spreading toward the portion of the column formed by the first concrete. It is estimated that the stress acting on the second concrete spreads at an angle of 45° to the underside of the beam toward the portion of the column formed by the first concrete.

[0014] According to the above configuration, the inclination angle A1 of the straight line L1 is set to a value within a range of 45° or more and less than 90°, and the inclination angle A2 of the straight line L2 is set to a value within a range of 45° or more and less than 90°. By determining the inclination angles A1 and A2 in this manner, the distances X1 and X2, which are the upper limits of the overhang amounts H1 and H2, are appropriately determined. As a result, the area of ​​the first concrete of the pillar that receives the above-mentioned stress from the second concrete is appropriately determined by setting the overhang amounts H1 and H2 to be equal to or less than the distances X1 and X2.

[0015] In the above-mentioned beam-column joint structure, the inclination angles A1 and A2 and the overhang amounts H1 and H2 can be determined as follows: The inclination angles A1 and A2 are each set to 45°. The overhang amount H1 is set to the distance X1. The overhang amount H2 is set to the distance X2.

[0016] According to the above configuration, by setting the inclination angles A1 and A2 to 45°, the distances X1 and X2, which are the upper limits of the protrusion amounts H1 and H2, are more appropriately determined. Furthermore, by setting the protrusion amounts H1 and H2 to the distances X1 and X2, the area of ​​the first concrete of the pillar that receives the above stress from the second concrete is more appropriately determined. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 is a perspective view showing a column-beam joint in a building. [Diagram 2] 2 is a cross-sectional view showing the column-beam joint and its periphery in FIG. 1 as viewed from the direction of arrows II-II. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, one embodiment of a beam-column joint structure will be described with reference to Figs. As shown in Figure 1, a building constructed using the RC column and S beam construction method (RCS construction method) has reinforced concrete columns 11 and steel beams 12. The steel frame that forms the beam 12 has plate-shaped webs 12a that stand upright in the vertical direction, and flanges 12b that protrude horizontally from both the top and bottom ends of the webs 12a. The flanges 12b extend in the longitudinal direction of the steel frame.

[0019] Such a building has a column-beam joint 13. The column-beam joint 13 is a location in the building where beams 12 intersect with each other and where the beams 12 intersect with the column 11. Between the intersecting beams 12 at the column-beam joint 13, closing plates 15 bent into an L shape are disposed at positions corresponding to the outer surfaces of the columns 11. The closing plates 15 are joined to the webs 12a and flanges 12b of the beams 12.

[0020] In the RC-column / S-beam construction method for buildings, after forming a column 11 of reinforced concrete construction, an intersection of beams 12 is placed at the top end of the column 11. Furthermore, in the portion surrounded by a closing plate 15 at the intersection of beams 12 (column-beam joint 13), reinforcing bars 16 for forming a column 11 above the column-beam joint 13 are passed through and concrete is poured. After that, a column 11 above the column-beam joint 13 is formed above the column-beam joint 13. In the RC-column / S-beam construction method for buildings, the columns 11 and beams 12 are formed in stages toward the upper part in this manner. In the column-beam joint 13 of a building built using the RC-column / S-beam construction method, the closing plate 15 provides shear resistance and also restrains the concrete in the column-beam joint 13.

[0021] A first concrete 21 is used as the concrete forming the pillar 11. The inside of the portion surrounded by the closing plate 15 in the column-beam joint 13 is filled with a second concrete 22 having a higher strength than the first concrete 21. The second concrete 22 having a higher strength than the first concrete 21 is more expensive than the first concrete 21.

[0022] The second concrete 22 protrudes toward both the column 11 located above the column-beam joint 13 and the column 11 located below the column-beam joint 13, thereby becoming part of the concrete forming the column 11. For this reason, of the concrete forming the column 11, the concrete in the portion in contact with the column-beam joint 13 becomes the second concrete 22, and the concrete in other portions becomes the first concrete 21. The second concrete 22 of the concrete forming the column 11 comes into contact with the beam 12 at the column-beam joint 13.

[0023] <Regarding the second concrete 22 that protrudes from the column-beam joint 13 into the column 11> 2 shows the amount of protrusion H1 of the second concrete 22 protruding from the portion surrounded by the closing plate 15 of the column-beam joint 13 toward the column 11 located above the column-beam joint 13. It is considered that the amount of protrusion H1 is equal to or less than the distance X1. More specifically, the amount of protrusion H1 in this embodiment is set to the distance X1.

[0024] The distance X1 is determined as follows: A straight line L1 is defined, which extends from the edge in the width direction of the upper surface of the beam 12 located at the column-beam joint 13 toward the upper side and the outer side of the beam 12 in the width direction to the side surface of the column 11 located above the column-beam joint 13. Then, the distance from the intersection P1 between the straight line L1 and the side surface to the height position of the upper surface of the beam 12 is determined as the distance X1.

[0025] The inclination angle A1 of the straight line L1 with respect to the upper surface of the beam 12 is set to a value within a range of 45° or more and less than 90°. The range here is preferably 45° to 70°, and more preferably 45° to 55°, for example. In this embodiment, the inclination angle A1 is set to 45°.

[0026] 2 also shows the amount of protrusion H2 of the second concrete 22 protruding from the portion surrounded by the closing plate 15 of the column-beam joint 13 toward the column 11 located below the column-beam joint 13. It is considered that the amount of protrusion H2 is equal to or less than the distance X2. More specifically, the amount of protrusion H2 in this embodiment is the distance X2.

[0027] The distance X2 is determined as follows: A straight line L2 is defined, which extends downward from the widthwise edge of the underside of the beam 12 located at the column-beam joint 13 toward the outer side of the beam 12 in the widthwise direction to the side surface of the column 11 located below the column-beam joint 13. The distance from an intersection P2 between the straight line L2 and the side surface to the height position of the underside of the beam 12 is determined as the distance X2.

[0028] The inclination angle A2 of the straight line L2 with respect to the upper surface of the beam 12 is set to a value within a range of 45° or more and less than 90°. The range here is preferably 45° to 70°, and more preferably 45° to 55°. In this embodiment, the inclination angle A2 is set to 45°.

[0029] Next, the effects of the column-beam joint structure of this embodiment will be described. (1) The portion of the column-beam joint 13 surrounded by the closing plate 15 is filled with the second concrete 22. This second concrete 22 protrudes onto the column 11 located above the column-beam joint 13, and also protrudes onto the column 11 located below the column-beam joint 13. For this reason, of the concrete forming the column 11 located above the column-beam joint 13, the concrete at the portion in contact with the column-beam joint 13 becomes the second concrete 22, and the concrete at the other portion becomes the first concrete 21. Also, of the concrete forming the column 11 located below the column-beam joint 13, the concrete at the portion in contact with the column-beam joint 13 becomes the second concrete 22, and the concrete at the other portion becomes the first concrete 21.

[0030] The beam 12 passing through the beam-column joint 13 is in contact with the second concrete 22 forming the column 11. An upward or downward force from the beam 12 acts on the column 11. When the force from the beam 12 acts on the column 11, the force is received by the second concrete 22 forming the portion of the column 11 that contacts the beam 12 at the beam-column joint 13. In detail, when an upward force from the beam 12 acts on the column 11 located above the beam-column joint 13, the force is received by the second concrete 22 forming the portion of the column 11 that contacts the beam 12 at the beam-column joint 13. When a downward force from the beam 12 acts on the column 11 located below the beam-column joint 13, the force is received by the second concrete 22 forming the portion of the column 11 that contacts the beam 12 at the beam-column joint 13.

[0031] This allows the concrete (second concrete 22) forming the portion of the column 11 in contact with the beam 12 to have the bearing strength to withstand the above force. Also, the first concrete 21, which has a lower strength than the second concrete 22, is used as the concrete forming the column 11 in the portions of the column-beam joint 13 of the column 11 other than the portion in contact with the beam 12. This makes it possible to reduce the amount of second concrete 22 used as the concrete forming the column 11, thereby preventing the cost of building from increasing.

[0032] (2) The protrusion amount H1 of the portion of the second concrete 22 protruding from the portion surrounded by the closing plate 15 of the column-beam joint 13 toward the column 11 located above the column-beam joint 13 is set to be equal to or less than the distance X1. This distance X1 is determined as follows. That is, a straight line L1 is defined that extends from the edge in the width direction of the upper surface of the beam 12 located at the column-beam joint 13 upward and toward the outer side in the width direction of the beam 12 to the side surface of the column 11 located above the column-beam joint 13. Then, the distance from the intersection point P1 between the straight line L1 and the side surface to the height position of the upper surface of the beam 12 is determined to be the distance X1.

[0033] Of the concrete forming the column 11 located above the column-beam joint 13, the second concrete 22 forming the portion in contact with the column-beam joint 13 receives an upward force from the beam 12. The stress based on the force in the second concrete 22 spreads toward the portion of the column 11 formed by the first concrete 21. This expands the area of ​​the first concrete 21 of the column 11 that receives the stress from the second concrete 22. Although there is an upper limit to this expansion of area, the expansion of the area is kept below the upper limit by setting the overhang amount H1 to the distance X1 or less. This makes it possible to prevent the second concrete 22 from being used in an excessively large amount as the concrete forming the column 11.

[0034] (3) When an upward force from the beam 12 acts on the column 11 located above the beam-column joint 13, a stress based on the force is generated in the second concrete 22 forming the portion of the column 11 in contact with the beam 12 at the beam-column joint 13, so as to spread toward the portion of the column 11 formed by the first concrete 21. It is presumed that the stress acting on the second concrete 22 spreads toward the portion of the column 11 formed by the first concrete 21 at an angle of 45° with respect to the upper surface of the beam 12. Taking this into consideration, the inclination angle A1 of the straight line L1 is set to a value within a range of 45° or more and less than 90°. By determining the inclination angle A1 in this manner, the distance X1, which is the upper limit of the protrusion amount H1, can be appropriately determined.

[0035] (4) Since the inclination angle A1 is set to 45°, the distance X1, which is the upper limit of the protrusion amount H1, is more appropriately determined. Furthermore, since the protrusion amount H1 is set to the distance X1, the area of ​​the first concrete 21 of the column 11 located above the column-beam joint 13 that receives the above-mentioned stress from the second concrete 22 is more appropriately determined.

[0036] (5) The protrusion amount H2 of the portion of the second concrete 22 protruding from the portion surrounded by the closing plate 15 of the column-beam joint 13 toward the column 11 located below the column-beam joint 13 is set to be equal to or less than the distance X2. This distance X2 is determined as follows. That is, a straight line L2 is defined that extends downward from the edge in the width direction of the underside of the beam 12 located at the column-beam joint 13 toward the outer side in the width direction of the beam 12 to the side surface of the column 11 located below the column-beam joint 13. Then, the distance from the intersection point P2 between the straight line L2 and the side surface to the height position of the underside of the beam 12 is determined to be the distance X2.

[0037] Of the concrete forming the column 11 located below the column-beam joint 13, the second concrete 22 forming the portion in contact with the column-beam joint 13 receives a downward force from the beam 12. The stress based on the force in the second concrete 22 is generated so as to spread toward the portion of the column 11 formed by the first concrete 21. This causes the area of ​​the first concrete 21 of the column 11 that receives the stress from the second concrete 22 to be expanded. Although there is an upper limit to such expansion of the area, the expansion of the area is kept below the upper limit by setting the overhang amount H2 to be equal to or less than the distance X2. This makes it possible to prevent the second concrete 22 from being used in an excessively large amount as the concrete forming the column 11.

[0038] (6) When a downward force from the beam 12 acts on the column 11 located below the beam-column joint 13, a stress based on the force is generated in the second concrete 22 forming the portion of the column 11 in contact with the beam 12 at the beam-column joint 13 so as to spread toward the portion of the column 11 formed by the first concrete 21. It is presumed that the stress acting on the second concrete 22 spreads toward the portion of the column 11 formed by the first concrete 21 at an angle of 45° with respect to the lower surface of the beam 12. Taking this into consideration, the inclination angle A2 of the straight line L2 is set to a value within a range of 45° or more and less than 90°. By determining the inclination angle A2 in this manner, the distance X2, which is the upper limit of the protrusion amount H2, can be appropriately determined.

[0039] (7) Since the inclination angle A2 is set to 45°, the distance X2, which is the upper limit of the protrusion amount H2, is more appropriately determined. Furthermore, since the protrusion amount H2 is set to the distance X2, the area of ​​the first concrete 21 of the column 11 located below the column-beam joint 13 that receives the above-mentioned stress from the second concrete 22 is more appropriately determined.

[0040] The above embodiment can be modified, for example, as follows: The above embodiment and the following modified examples can be combined with each other to the extent that no technical contradiction occurs. The inclination angles A1 and A2 may be changed to values ​​other than 45° as appropriate.

[0041] The protrusion amount H1 may be less than the distance X1. Also, the protrusion amount H1 may be greater than the distance X1. The protrusion amount H2 may be less than the distance X2. Also, the protrusion amount H2 may be greater than the distance X2.

[0042] The second concrete 22 may protrude from the portion surrounded by the closing plate 15 at the column-beam joint 13 toward either the column 11 located above the column-beam joint 13 or the column 11 located below the column-beam joint 13. [Explanation of symbols]

[0043] 11…Pillar 12...beam 12a…Web 12b...Flange 13…Column beam joint 15…Blocking plate 16…Reinforced concrete 21...First Concrete 22...Second Concrete

Claims

1. This is applied to a column-beam joint where a reinforced concrete column also intersects with a steel frame beam, the column-beam joint is surrounded by a closing plate disposed in the portion sandwiched between the intersecting beams, and the inside of the portion surrounded by the closing plate in the column-beam joint is filled with concrete, A first concrete is used as the concrete for forming the pillar, The inside of the portion surrounded by the closing plate in the column-beam joint is filled with a second concrete having a strength higher than that of the first concrete, A column-beam joint structure in which the second concrete protrudes toward at least one of the column located above the column-beam joint and the column located below the column-beam joint, thereby becoming part of the concrete forming the column on the protruding side.

2. 2. The column-beam joint structure according to claim 1, wherein the second concrete protrudes toward both the column located above the column-beam joint and the column located below the column-beam joint.

3. a straight line L1 is defined extending upward and outward in the width direction from the edge of the upper surface of the beam located at the column-beam joint to the side surface of the column located above the column-beam joint, and a distance X1 is defined from the intersection of the straight line L1 and the side surface to the height position of the upper surface of the beam, a protrusion amount H1 of a portion of the second concrete protruding from a portion of the column-beam joint surrounded by the closing plate toward the column located above the column-beam joint is set to be equal to or less than the distance X1, 3. The column-beam joint structure according to claim 2, wherein a straight line L2 is defined extending downward and outward in the width direction from an edge of the underside of the beam located at the column-beam joint to a side surface of the column located below the column-beam joint, and a distance X2 is defined from an intersection of the straight line L2 and the side surface to a height position of the underside of the beam. The second concrete protrudes from a portion of the second concrete surrounded by the cover plate at the column-beam joint toward the column located below the column-beam joint by an amount H2 equal to or less than the distance X2.

4. The inclination angle A1 of the straight line L1 with respect to the upper surface of the beam is a value in the range of 45° or more and less than 90°, The column-beam joint structure according to claim 3 , wherein an inclination angle A2 of the straight line L2 with respect to the lower surface of the beam is within a range of 45° or more and less than 90°.

5. 5. The column-beam joint structure according to claim 4, wherein the inclination angle A1 and the inclination angle A2 are 45 degrees, the protrusion amount H1 is set to the distance X1, and the protrusion amount H2 is set to the distance X2.

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