JP2021195805A - Joint structure of column and beam - Google Patents

Abstract

To provide a joint structure of a column and a beam capable of enhancing the frame rigidity.SOLUTION: A joint structure 100 of a column and a beam is a joint structure of an H-shaped steel beam and a column of a concrete filled steel tube structure that comprises a steel pipe 21 that extends in a vertical direction and is formed in a cylindrical shape, a main bar 22 that is arranged inside the steel pipe 21 and extends in the vertical direction, and a concrete section 23 that is filled inside the steel pipe 21. The joint structure is characterized by having an upper diaphragm 31 and a lower diaphragm 32 that are installed on an outer surface 21a of the steel pipe 21, have a contour that is circular in plan view, and are joined to upper and lower flanges 11, 12 of the beam 1, and a plurality of cotters 33 that protrude inward from an inner surface 21d of the steel pipe 21.SELECTED DRAWING: Figure 1

Description

The present invention relates to a joint structure of columns and beams.

Conventionally, a joint structure of a concrete-filled steel pipe structure (CFT structure) column in which a steel pipe is filled with reinforcing bars and concrete and a steel frame structure (S structure) beam has been known.

In Patent Document 1, a recess (notch) recessed from the side surface of the column is provided, and the end of the beam is inserted into the recess to reach the inside of the column to join the column and the beam. A beam penetration type has been proposed.

Patent Document 2 proposes an outer diaphragm type in which an outer diaphragm is welded to the outer surface of the column, and the outer diaphragm and the flange of the beam are welded to join the column and the beam.

By adopting a circular outer diaphragm that forms a circular ring in a plan view, it is possible to formulate a frame plan that fits well with the outer wall, etc., and join details of diagonal beams, compared to a rectangular outer diaphragm that forms a rectangular ring in a plan view. Can be simplified.

Further, the upper and lower columns are joined by a main bar (joined reinforcing bar) arranged inside the steel pipe and filled concrete, and the edges of the upper and lower steel pipes are cut off.

Japanese Unexamined Patent Publication No. 2016-142062 JP-A-2017-160754

However, in the circular outer diaphragm, when the outer diaphragm resists the tensile force from the beam, it is more easily deformed in the plate surface inward direction and the plate surface outer direction than the rectangular outer diaphragm, and the stress state is complicated. There is a problem that the pillars may come off from the part, leading to a decrease in the rigidity of the frame.

Therefore, the present invention has been made in view of the above circumstances, and provides a joint structure between a column and a beam capable of increasing the frame rigidity.

In order to achieve the above object, the present invention employs the following means.
That is, the joint structure between the column and the beam according to the present invention is filled in the steel pipe formed in a cylindrical shape extending in the vertical direction, the main bar arranged inside the steel pipe and extending in the vertical direction, and the inside of the steel pipe. It is a joint structure of a pillar of a concrete-filled steel pipe structure having a steel pipe and a beam of H-shaped steel, and is provided on the outer surface of the steel pipe and has an outer shape in a circular shape in a plan view, above and below the beam. The upper diaphragm and the lower diaphragm to be joined to the flange and a plurality of cotters protruding inward from the inner surface of the steel pipe are provided, and at least two of the beams are arranged orthogonally to the pillar in a plan view. The line connecting the center of the steel pipe and the extending direction of the beam is defined as the first virtual line, and the line extending between the two first virtual lines orthogonal to the center of the steel pipe in plan view is the second. It is a virtual line, and the cotter is arranged on the second virtual line.

In the joint structure of the column and the beam configured in this way, a plurality of cotters protruding inward from the inner surface of the steel pipe are provided. By fixing the cotter to the concrete portion, the adhesiveness between the steel pipe and the concrete portion is enhanced, and the frame rigidity can be enhanced.
Further, a beam is joined on the first virtual line in the steel pipe, and a cotter is provided on the second virtual line between the first virtual lines orthogonal to each other. Therefore, the fixing property with the concrete portion in the vicinity of the second virtual line (the portion not joined to the beam) in the steel pipe is improved, and the rigidity in the column axial direction can be reinforced.

Further, the joint structure between the column and the beam according to the present invention is filled in the steel pipe formed in a cylindrical shape extending in the vertical direction, the main bar arranged inside the steel pipe, and the main bar extending in the vertical direction, and the inside of the steel pipe. It is a joint structure of a pillar of a concrete-filled steel pipe structure having a steel pipe and an H-shaped steel beam, which is provided on the outer surface of the steel pipe and has an outer shape of a circular shape in a plan view, above and below the beam. It is characterized by comprising an upper diaphragm and a lower diaphragm to be joined to the flange, and stiffening portions provided on at least one of the upper part and the lower part of the upper diaphragm and the lower diaphragm.

In the joint structure of the column and the beam configured in this way, the tensile rigidity in the beam tensile direction is reinforced by the stiffening portions provided on at least one of the upper part and the lower part of the upper diaphragm and the lower diaphragm, and the frame rigidity is enhanced. be able to.

Further, in the joint structure between the column and the beam according to the present invention, the stiffening portion may be arranged on a line connecting the center of the steel pipe and the extending direction of the beam.

In the column-beam joint structure configured in this way, the stiffening section is generally placed on the line connecting the center of the steel pipe and the extending direction of the beam when designing the upper and lower diaphragms ( Damage to the upper and lower diaphragms near the expected yield line (such as with a pointer) is suppressed.

According to the joint structure of the column and the beam according to the present invention, the frame rigidity can be increased.

It shows the joint structure of a column and a beam which concerns on 1st Embodiment of this invention, is (a) a horizontal sectional view, and (b) (a) is a sectional view taken along the line AA. It shows the joint structure of a column and a beam which concerns on 2nd Embodiment of this invention, is (a) a horizontal sectional view, and is (b) (a) a BB line sectional view. The analysis result which confirms the effect of the stiffening part in the joint structure of a column and a beam which concerns on the 2nd Embodiment of this invention is shown.

(First Embodiment)
The joint structure between the column and the beam according to the first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a joint structure of a column and a beam according to the first embodiment of the present invention, (a) a horizontal sectional view, and (b) (a) a sectional view taken along line AA.
As shown in FIG. 1, in the joint structure 100 of the column and the beam of the present embodiment, the steel-framed beam 1 is joined to the column 2 of the concrete-filled steel pipe structure. In this embodiment, four beams 1 are arranged orthogonally to the pillar 2 in a plan view. The number of beams 1 can be set as appropriate.

Each beam 1 is made of H-shaped steel. The beam 1 has an upper flange 11, a lower flange 12, and a web 13.

The upper flange 11 and the lower flange 12 are arranged apart from each other in the vertical direction. The upper flange 11 and the lower flange 12 are formed in a plate shape. The plate surfaces of the upper flange 11 and the lower flange 12 are arranged along the horizontal plane.

The web 13 connects the upper flange 11 and the lower flange 12. The web 13 is formed in a plate shape. The plate surface of the web 13 is arranged along the vertical plane.

The column 2 has a steel pipe 21, a plurality of main bars 22, and a concrete portion 23. The steel pipe 21 is formed in a cylindrical shape with the vertical direction as the axial direction. The steel pipe 21 has a steel pipe main body 21b arranged above and below the beam 1 and a closing plate 21c arranged at a height corresponding to the beam 1. Both the steel pipe main body 21b and the closing plate 21c are formed in a cylindrical shape with the vertical direction as the axial direction. The steel pipe body 21b and the closing plate 21c are metal touched without welding.

The main bar 22 is arranged along the inside of the steel pipe 21. The main bars 22 are arranged at intervals in the circumferential direction. The main bar 22 extends in the vertical direction. In the present embodiment, 24 main bars 22 are arranged, but the number of main bars 22 can be appropriately set. The concrete portion 23 is filled inside the steel pipe 21. The main bar 22 is fixed to the concrete portion 23.

The column-beam joint structure 100 includes an upper diaphragm 31, a lower diaphragm 32, and a plurality of cotters 33.

The upper diaphragm 31 and the lower diaphragm 32 have a function of transmitting a load from the beam 1 to the column 2. The upper diaphragm 31 and the lower diaphragm 32 are provided so as to project radially outward from the outer surface 21a of the steel pipe 21. The upper diaphragm 31 and the lower diaphragm 32 are joined to the steel pipe 21 by welding or the like. In the present embodiment, the upper diaphragm 31 and the lower diaphragm 32 are joined between the steel pipe main body 21b and the closing plate 21c.

The upper diaphragm 31 is arranged at substantially the same height as the upper flange 11 of the beam 1. The thickness of the upper diaphragm 31 is slightly thicker than the thickness of the upper flange 11. The upper diaphragm 31 is joined to the upper flange 11 by welding or the like.

The lower diaphragm 32 is arranged at substantially the same height as the lower flange 12 of the beam 1. The thickness of the lower diaphragm 32 is slightly thicker than the thickness of the lower flange 12. The lower diaphragm 32 is joined to the lower flange 12 by welding or the like.

The upper diaphragm 31 and the lower diaphragm 32 have a predetermined thickness in the vertical direction and are formed in an annular plate shape. As shown in FIG. 1A, the outer peripheral surface 30a of the upper diaphragm 31 and the lower diaphragm 32 has a substantially circular shape. Of the outer peripheral surfaces of the upper diaphragm 31 and the lower diaphragm 32, the portion 30b joined to the upper flange 11 and the lower flange 12 has a linear shape corresponding to the end faces of the upper flange 11 and the lower flange 12.

It is provided so as to project inward in the radial direction from the inner surface 21d of the closing plate 21c of the cotter 33 and the steel pipe 21. The cotter 33 is made of a metal material such as a steel plate piece. The cotter 33 is joined to the inner surface 21d of the closing plate 21c by welding or the like.

In the present embodiment, the cotters 33 are arranged at four locations at equal intervals in the circumferential direction on the inner surface 21d of the closing plate 21c, and in three rows above and below. The cotter 33 suppresses the vertical displacement of the concrete portion 23. The number and arrangement positions of the cotters 33 can be appropriately set.

In a plan view, the line connecting the center O of the steel pipe 21 and the extending direction of the beam 1 is defined as the first virtual line L1. In a plan view, a line orthogonal to the center O of the steel pipe 21 and extending to the middle (center) of two adjacent first virtual lines L1 is referred to as a second virtual line L2. The cotter 33 is arranged on the second virtual line L2.

As shown in FIG. 1 (b), the cotter 33 has an upper end portion 21u (height position directly below the upper diaphragm 31), a lower end portion 21w (height position directly above the lower diaphragm 32), and a vertical direction of the closing plate 21c. It is installed in the center of. The cotter 33 may be arranged below with a gap from the upper end portion 21u of the closing plate 21c, or may be arranged above with a gap from the lower end portion 21w of the closing plate 21c.

The cotter 33 has a rectangular shape in a vertical cross-sectional view passing through the center O of the steel pipe 21 and the cotter 33. As shown in FIG. 1A, in the horizontal cross-sectional view, the surface joined to the inner surface 21d of the closing plate 21c has a shape (curved surface) corresponding to the inner surface 21d of the closing plate 21c, but is substantially rectangular. It has a shape. Since the horizontal cross section of the cotter 33 is substantially rectangular, it is possible to obtain the anti-slip reaction force of the concrete portion 23 more efficiently than, for example, a cotter having a circular cross section. It is preferable that the cotter 33 is formed with a slight taper in order to avoid stress concentration.

In the joint structure 100 of the column and the beam configured in this way, a plurality of cotters 33 protruding inward from the inner surface 21d of the steel pipe 21 are provided. By fixing the cotter 33 to the concrete portion 23, the adhesiveness between the steel pipe 21 and the concrete portion 23 is enhanced, and the frame rigidity can be enhanced.

Further, the beam 1 is joined on the first virtual line L1 in the steel pipe 21, and the cotter 33 is provided on the second virtual line L2 between the first virtual lines L1 orthogonal to each other. Therefore, the fixability of the steel pipe 21 to the concrete portion 23 near the second virtual line L2 (the portion not joined to the beam 1) is improved, and the rigidity in the column axial direction can be reinforced.

(Second embodiment)
Next, the joint structure between the column and the beam according to the second embodiment will be described mainly with reference to FIGS. 2 and 3. The components having the same functions as the components of the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 2 shows a joint structure of a column and a beam according to a second embodiment of the present invention, (a) a horizontal sectional view, and (b) (a) a sectional view taken along line BB.
As shown in FIG. 2, the joint structure 100A between the column and the beam of the present embodiment includes an upper diaphragm 31 and a lower diaphragm 32, and a plurality of upper stiffening portions 34 and a lower stiffening portion 35.

The upper stiffening portion 34 is provided on the upper surface (upper portion) of the upper diaphragm 31 and the lower diaphragm 32. The lower stiffening portion 35 is provided on the lower surface (lower portion) of the upper diaphragm 31 and the lower diaphragm 32. The upper stiffening portion 34 and the lower stiffening portion 35 are plate-shaped members having a predetermined thickness in the vertical direction. The upper stiffening portion 34 and the lower stiffening portion 35 are made of a metal material such as a steel plate.

The upper stiffening portion 34 and the lower stiffening portion 35 are provided at four positions at intervals in the circumferential direction. In this embodiment, it is arranged on the first virtual line L1. The width of the upper stiffening portion 34 and the lower stiffening portion 35 is longer than the width of the upper flange 11 and the lower flange 12 of the beam 1.

Next, the analysis of the joint structure 100A between the column and the beam will be described.
The effects of the upper stiffening portion 34 and the lower stiffening portion 35 were confirmed.
The upper flange 11 and the lower flange 12 have a width of 300 mm and a plate thickness of 28 mm. The upper diaphragm 31 and the lower diaphragm 32 have a plate thickness of 45 mm. Assuming that the stiffening portion is provided on both the upper and lower sides or the upper and lower sides of the upper diaphragm 31 and the lower diaphragm 32, the plate thickness of the stiffening portion is 3 mm (1.06 times) in the first embodiment, and the stiffening portion is provided in the second embodiment. The plate thickness was 6 mm (1.13 times), the plate thickness of the stiffening portion was 9 mm (1.2 times) in Example 3, and the plate thickness of the stiffening portion was 45 mm (2 times) in Example 4. The steel pipe (blocking plate) to which the diaphragm is attached is not considered. In addition, the plate thickness of the stiffening portion means the total of the upper and lower parts in the case of both upper and lower sides.

As shown in FIG. 3, it can be seen that the thicker the stiffening portion, the higher the initial rigidity and the smaller the deformation at the yield strength (2750 kN) level.

In the joint structure 100A between the column and the beam configured in this way, the upper stiffening portion 34 and the lower stiffening portion 35 provided at the upper and lower portions of the upper diaphragm 31 and the lower diaphragm 32 pull the beam in the tensile direction. The rigidity is reinforced and the frame rigidity can be increased.

Further, by arranging the upper stiffening portion 34 and the lower stiffening portion 35 on the first virtual line L connecting the center O of the steel pipe 21 and the extending direction of the beam 1, the design of the upper diaphragm 31 and the lower diaphragm 32 is performed. Damage to the upper diaphragm 31 and the lower diaphragm 32 in the vicinity of the yield line, which is generally assumed (by a pointer or the like), is suppressed.

The assembly procedure shown in the above-described embodiment, or the shapes and combinations of the constituent members are examples, and various changes can be made based on the design requirements and the like without departing from the gist of the present invention.

In the embodiment shown above, the upper stiffening portion 34 is provided on the upper part of the upper diaphragm 31 and the lower diaphragm 32, and the lower stiffening portion 35 is provided on the lower part of the upper diaphragm 31 and the lower diaphragm 32. Is not limited to this. The stiffening portion may be provided on at least one of the upper part and the lower part of the upper diaphragm 31 and the lower diaphragm 32.

1 Beam 2 Column 11 Upper flange 12 Lower flange 21 Steel pipe 21a Outer surface 21d Inner surface 22 Main bar 23 Concrete part 31 Upper diaphragm 32 Lower diaphragm 33 Cotta 34 Upper stiffening part (stiffening part)
35 Lower stiffening part (stiffening part)
100 Join structure between column and beam L1 First virtual line L2 Second virtual line O Center

Claims (3)

A concrete-filled steel pipe pillar having a steel pipe extending in the vertical direction and formed in a cylindrical shape, a main bar arranged inside the steel pipe and extending in the vertical direction, and a concrete portion filled inside the steel pipe. It is a joint structure with an H-shaped steel beam.
An upper diaphragm and a lower diaphragm which are provided on the outer surface of the steel pipe and have a circular shape in a plan view and are joined to the upper and lower flanges of the beam.
With a plurality of cotters protruding inward from the inner surface of the steel pipe,
At least two of the beams are arranged orthogonally to the pillar.
In a plan view, the line connecting the center of the steel pipe and the extending direction of the beam is defined as the first virtual line.
In a plan view, a line extending between the two first virtual lines orthogonal to the center of the steel pipe is defined as a second virtual line.
The cotter is a joint structure of a column and a beam, characterized in that it is arranged on the second virtual line. A concrete-filled steel pipe pillar having a steel pipe extending in the vertical direction and formed in a cylindrical shape, a main bar arranged inside the steel pipe and extending in the vertical direction, and a concrete portion filled inside the steel pipe. It is a joint structure with an H-shaped steel beam.
An upper diaphragm and a lower diaphragm which are provided on the outer surface of the steel pipe and have a circular shape in a plan view and are joined to the upper and lower flanges of the beam.
A column-beam joint structure comprising: a stiffening portion provided on at least one of an upper part and a lower part of the upper diaphragm and the lower diaphragm. The joint structure between a column and a beam according to claim 2, wherein the stiffening portion is arranged on a line connecting the center of the steel pipe and the extending direction of the beam.

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