JP6338100B2 - Joint structure between pillars and building - Google Patents

Description

  The present invention relates to a joint structure between columns and a building.

Conventionally, a composite structure building in which columns of different structures are joined together, such as a building in which reinforced concrete columns and concrete-filled steel pipe columns are joined in a vertical direction, is known. As a structure of a pillar of such a composite structure building, a lower layer composed of concrete-filled steel pipe columns, a boundary layer composed of one layer height disposed above the lower layer, and disposed above the boundary layer The thing provided with the upper layer part comprised by the reinforced concrete pillar is proposed (refer the following patent document 1).
The boundary layer in the column structure of the above composite structure building consists of the steel pipe that forms the outer shell, the main bars inserted into the steel pipe, the strips wound around the main bars, the concrete filled in the steel pipes, And a stud provided at a lower portion of the steel pipe.

JP 2009-2006 JP

  However, in the structure of the pillar of the composite structure building described in Patent Document 1 above, the boundary layer cannot sufficiently resist the axial force acting from the upper floor, so there is a possibility that it will buckle out of plane.

  Then, this invention is made | formed in view of the said situation, and provides the junction structure and building of columns which can suppress an out-of-plane buckling.

In order to achieve the above object, the present invention employs the following means.
That is, the column-to-column connection structure according to the present invention includes a concrete portion and a first column of reinforced concrete having a column main reinforcing bar extending in the vertical direction in the concrete portion, and a steel structure or filling disposed above the first column. It is a joining structure of columns that join the second column of the steel pipe concrete structure, and the first column and the second column are joined via a stress switching unit, and the stress switching unit is A lower part of the second pillar, an outer peripheral side of the lower part of the second pillar, continuous with the pillar main bars and extending in the vertical direction from the concrete part, and surrounding all the main bars. A steel pipe that is arranged over the entire length in the vertical direction and is formed in a rectangular tube shape that extends in the vertical direction, and a filled concrete portion that is filled in the steel pipe, and the steel pipe includes a peripheral surface of the steel pipe. To protrude One, the vertical direction in a plurality of spaced apart, characterized in that suppressing ribs plane buckling of the steel pipe is formed.

  In the joining structure of the columns configured as described above, the first column and the second column are established by fixing the main reinforcement portion of the first column and the lower portion of the second column to the filled concrete portion filled in the steel pipe. And are joined. Moreover, since the rib which suppresses an out-of-plane buckling is provided in the steel pipe arrange | positioned at the outer peripheral side of the 2nd pillar, it can resist the axial force which acts on a 2nd pillar. Therefore, out-of-plane buckling of the steel pipe can be suppressed.

  Moreover, as for the joining structure of the pillars which concern on this invention, it is preferable that the said rib is formed over the perimeter of the circumferential direction of the said steel pipe.

  In the joining structure of the columns configured as described above, the ribs are formed over the entire circumference in the circumferential direction of the steel pipe, so that out-of-plane buckling of the steel pipe can be suppressed in the circumferential direction.

  Moreover, in the joint structure between columns according to the present invention, the concrete of the filled concrete portion may be fiber reinforced concrete.

  In the joint structure between the columns configured as described above, cracks of the fiber reinforced concrete due to the axial force can be suppressed by the bridging effect of the fiber reinforced concrete filled in the steel pipe. Therefore, the out-of-plane buckling of the steel pipe can be effectively suppressed.

  Moreover, the building of pillars which concerns on this invention is a building provided with the junction structure of pillars as described in any one of the above.

  In the building of columns configured in this way, the steel pipe disposed on the outer peripheral side of the second column is provided with ribs that suppress out-of-plane buckling, so that the axial force acting on the second column Can resist. Therefore, out-of-plane buckling of the steel pipe can be suppressed.

  According to the column-to-column junction structure and the building according to the present invention, out-of-plane buckling can be suppressed.

It is a schematic front view which shows the building which concerns on one Embodiment of this invention. It is a longitudinal cross-sectional view which shows the structure of the junction structure of the pillars in the building which concerns on one Embodiment of this invention. FIG. 3 is a cross - sectional view taken along line AA in FIG. 2, showing a configuration of a joint structure between columns in a building according to an embodiment of the present invention. It is a schematic front view which shows the building which concerns on the modification of one Embodiment of this invention.

(Building)
The building which concerns on one Embodiment of this invention is demonstrated using drawing.
As shown in FIG. 1, a building 100 according to the present embodiment includes a floor slab F0 on the first basement floor extending in the horizontal direction, a first column 1 made of reinforced concrete extending in the vertical direction from the floor slab F0, and And a second column 2 made of filled steel pipe concrete, which is disposed above one column 1.
Furthermore, the building 100 includes a third pillar 3 disposed on the upper side of the second pillar 2, and a floor slab F1 on the first floor extending in the horizontal direction from a joint portion between the second pillar 2 and the third pillar 3. ing.

  That is, the 1st pillar 1 and the 2nd pillar 2 are used as the pillar of the 1st underground, and the 3rd pillar 3 is used as the pillar of the ground 1st floor. The 1st pillar 1 and the 2nd pillar 2 are joined via the stress switching part 5 mentioned later (joint structure of pillars).

(First pillar)
As shown in FIGS. 2 and 3, the first pillar 1 has a plurality of main reinforcing bars 10 extending in the vertical direction with a predetermined interval in the horizontal direction, and a vertical interval so as to bundle the plurality of main reinforcing bars 10. A plurality of hoops 12 disposed and a first concrete portion 13 that is concrete filled in a substantially rectangular shape in plan view so as to cover the plurality of main bars 10 and the plurality of hoops 12. Yes.

  The plurality of main bars 10 are arranged at intervals so as to be along the outer peripheral surface of the first concrete portion 13 in plan view. The main muscle 10 extends to the upper part of the section X and the section X. Of the main reinforcement 10, a portion arranged in the section X is a column main reinforcement 11, and a portion arranged above the section X is a main reinforcement 70 constituting a stress switching unit 5 described later. That is, the column main reinforcement 11 and the main reinforcement 70 are continuously formed of, for example, steel bars for reinforced concrete.

  Further, the band 12 is arranged in the horizontal direction over the range of the section X. That is, the band 12 is wound around the column main bar 11 of the main bars 10.

  Further, the first concrete portion 13 is filled in the range of the section X. That is, the main reinforcement 70 protrudes upward from the upper surface of the first concrete part 13.

(Second pillar)
The second column 2 is disposed over a vertical section Y located above the section X, and is a square tube-shaped steel pipe (hereinafter referred to as a square steel pipe) 21 and a concrete filled in the square steel pipe 21. And a concrete portion 22.
In addition, the steel pipe 21 of the 2nd pillar 2 is not restricted to a rectangular tube shape, A cylindrical shape may be sufficient and the said shape can be selected suitably.

  The second column 2 is arranged inward of the first column 1 in plan view so that each side of the second column 2 is parallel to each side of the first column 1.

  A base plate 23 having a substantially rectangular shape in plan view is provided at the lower end of the square steel pipe 21. The outline of the base plate 23 in plan view is larger than the outline of the square steel pipe 21 in plan view and smaller than the outline of the first column 1 in plan view.

  Further, a substantially circular opening 23A penetrating in the vertical direction is formed in a substantially central portion of the base plate 23 in plan view.

  The square steel pipe 21 of the second pillar 2 is arranged over the range of the section Y. The second concrete portion 22 is filled over the section Y.

(Stress switching part)
The stress switching unit 5 is disposed over a section Z extending from the upper side of the section X to the lower portion of the section Y. The stress switching part 5 includes a lower part 2A of the second pillar 2, a main reinforcing part 70 of the main reinforcing part 10 of the first pillar 1 arranged on the outer peripheral side of the lower part 2A, and a bonded steel pipe 50 that surrounds the main reinforcing part 70. (Steel pipe) and a filled concrete portion 80 filled in the bonded steel pipe 50 are provided.

  The lower part 2 </ b> A of the second pillar 2 is a part arranged in the section Z of the second pillar 2. Further, the main reinforcement portion 70 is a portion of the main reinforcement 10 of the first pillar 1 that protrudes upward from the upper surface of the first concrete portion 13 and extends in the vertical direction, that is, a portion disposed in the section Z. The main muscle portion 70 extends to a position lower than the upper end of the section Z.

  The joining steel pipe 50 is a square tubular steel pipe extending in the vertical direction. The bonded steel pipe 50 is disposed over the entire length in the vertical direction, that is, over the entire length of the section Z.

  The outer shape in plan view of the bonded steel pipe 50 is substantially the same as the outer shape in plan view of the first column 1. Further, the bonded steel pipe 50 is disposed in contact with the upper side of the first column 1 so that the outer peripheral surface of the bonded steel pipe 50 is flush with the outer peripheral surface of the first column 1.

Further, the outer shape in plan view of the bonded steel pipe 50 is larger than the outer shape in plan view of the second pillar 2. That is, the lower part 2 </ b> A of the second pillar 2 is disposed inside the bonded steel pipe 50.
In this way, the bonded steel pipe 50 is disposed from the upper end of the first column 1 to the lower portion of the second column 2.

  An upper ridge 51 is formed on the upper end of the bonded steel pipe 50. The upper ridge 51 is formed in an annular shape in plan view so as to protrude inward from the inner peripheral surface of the bonded steel pipe 50 over the entire circumference in the circumferential direction, that is, along the inner peripheral surface of the bonded steel pipe 50. .

Further, a plurality of ribs 60 are formed in the bonded steel pipe 50 below the upper ridges 51 with intervals in the vertical direction. The rib 60 is formed in an annular shape in plan view so as to protrude inward from the inner peripheral surface of the bonded steel pipe 50 over the entire circumference in the circumferential direction, that is, along the inner peripheral surface of the bonded steel pipe 50. A plurality of ribs 60 are provided over the entire length of the section Z.
In the present embodiment, the rib 60 is provided up to a position above the lower end of the second pillar 2.

The rib 60 has a function of suppressing the out-of-plane buckling of the bonded steel pipe 50 against the axial force acting on the second column 2.
The rib 60 has a plurality of through holes 60A (see FIG. 3) penetrating in the vertical direction. The through hole 60A functions as a vent hole or a concrete passage hole when the filled concrete portion 80 is filled in the bonded steel pipe 50.

  Moreover, the inclined surface 52 formed so that it might go to the inner side of the 1st pillar 1 gradually toward the inner side of the 1st pillar 1 is provided in the lower end of the joining steel pipe 50 toward the upper direction from the downward direction.

  On the upper side of the inclined surface 52 of the bonded steel pipe 50, there is a lower convex strip 53 that protrudes inward from the inner peripheral surface of the bonded steel pipe 50 over the entire circumference in the circumferential direction. It is formed along the peripheral surface.

  The upper ridge 51 and the lower ridge 53 have a function of preventing deformation of the bonded steel pipe 50 against the support pressure acting on the bonded steel pipe 50 by the input shear force from the second column 2. doing.

  The filled concrete portion 80 is fiber-reinforced concrete filled in the bonded steel pipe 50 and outside the square steel pipe 21 of the second column 2 over the entire length of the bonded steel pipe 50. Fiber reinforced concrete is a concrete material in which synthetic fiber, steel fiber, or the like is combined with concrete.

  In this embodiment, steel fibers having a density of 7.85 g / cm 3, a tensile strength of 700 N / mm 2, a length of 30 mm, and a diameter of 0.6 mm are employed as the fibers. Moreover, the mixing rate of this fiber is a maximum of 0.75 vol. %.

  The bearing strength magnification of this fiber reinforced concrete is about 1.3 times the bearing strength magnification of plain concrete. Moreover, the yield strength of fiber reinforced concrete is about 1.2 times that of plain concrete.

  In the present embodiment, the first pillar 1, the second pillar 2, and the stress switching unit 5 are integrally formed of a precast concrete member, so that the fiber reinforced concrete is formed on the base plate 23 of the second pillar 2. The inside of the second pillar 2 is also filled through the opening 23A.

  That is, the second concrete part 22 of the second pillar 2, the filled concrete part 80 in the bonded steel pipe 50, and the first concrete part 13 of the first pillar 1 are integrally formed of fiber reinforced concrete.

In the joining structure of the pillars configured as described above, the main bar portion 70 of the first pillar 1 and the lower part 2A of the second pillar 2 are filled in the joining steel pipe 50 disposed on the outer peripheral side of the second pillar 2. It settles in the filled concrete part 80. Thereby, the 1st pillar 1 and the 2nd pillar 2 are joined.
Moreover, since the rib 60 which suppresses an out-of-plane buckling is provided in the joining steel pipe 50 of the outer peripheral side of the 2nd pillar 2, it can resist the axial force which acts on the 2nd pillar 2. FIG. Therefore, out-of-plane buckling of the bonded steel pipe 50 can be suppressed.

  Moreover, since the rib 60 is formed over the whole circumference of the joining steel pipe 50, the out-of-plane buckling of the joining steel pipe 50 can be suppressed over the whole circumference in the circumferential direction.

  The first concrete portion 13 of the first pillar 1, the second concrete portion 22 of the second pillar 2, and the filled concrete portion 80 in the bonded steel pipe 50 are made of fiber reinforced concrete. Therefore, cracking of the fiber reinforced concrete due to the axial force can be suppressed by the crosslinking effect of the fiber reinforced concrete. Therefore, the out-of-plane buckling of the bonded steel pipe 50 can be effectively suppressed.

  Moreover, since the inclined surface 52 is provided in the lower end of the joining steel pipe 50, the force which acts on the joining steel pipe 50 and the filling concrete part 80 of the zone Z goes down toward the 2nd pillar 2 along the inclined surface 52. Communicated. Therefore, cracks and the like do not occur in the filled concrete portion 80 and the first concrete portion 13 of the first pillar 1. Further, the axial force transmission prevents the first concrete portion 13 and the filled concrete portion 80 around the inclined surface 52 from falling off.

  In addition, when the stress switching unit is provided on the ground floor, a horizontal force acts greatly on the joint structure between the columns during an earthquake. For this reason, the length of the joining steel pipe 50 is lengthened so as to reduce the input shear force to the joining steel pipe 50, the plate thickness of the joining steel pipe 50 is increased in order to avoid the shear yield of the joining steel pipe 50, filled concrete In order to prevent the shear displacement by causing the part 80 and the bonded steel pipe 50 to behave integrally, it is necessary to take a design measure such as providing several protrusions such as bar steels by welding or the like along the material axial direction inside the bonded steel pipe 50. . However, when the stress switching unit 5 is provided on the basement floor such as the first basement floor as in the embodiment described above, the force acting on the joint structure between the columns is more than the axial force. Is relatively large, so there is no need to take the above measures, or a slower response is possible than when it is installed on the ground floor.

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

For example, as in the modification shown in FIG. 4, the stress switching unit 105 may be disposed so as to contact the upper surface of the floor slab F <b> 0. In this case, the column main reinforcement 11 (refer FIG. 2), the band 12 (refer FIG. 2), and the 1st concrete part 13 (refer FIG. 2) which comprise the 1st pillar 101 are provided in the area X1. In addition, the main reinforcement part 70 (refer FIG. 2) following the column main reinforcement 11 is extended to the area Z1.
The second pillar 102 is disposed over the section Y1.
The stress switching unit 105 is disposed over a section Z1 extending from the upper side of the section X1 to the lower portion of the section Y1.

In the embodiment described above, the portion extending in the vertical direction from the floor slab F0 is the first column 1 made of reinforced concrete, whereas in this modification, the portion extending in the vertical direction from the floor slab F0 is the stress switching unit 105. It is. Therefore, since the stress switching part 105 can be provided directly on the floor slab F0 without providing a reinforced concrete part that is weaker than the stress switching part 5, the axial strength can be improved.
The first column may be arranged so that the upper end of the first concrete portion of the first column reaches the middle of the floor slab F0 in the thickness direction, and the stress switching unit may be arranged continuously therewith. That is, the lower end of the stress switching part may reach the middle of the floor slab F0 in the thickness direction.

  For example, in embodiment shown above, the 1st pillar 1, the 2nd pillar 2, and the stress switching part 5 were mentioned as an example, and the case where it was comprised with the precast concrete member was demonstrated. However, this invention is not restricted to this, It is applicable also to the structure which builds the stress switching part 5 and the 2nd pillar 2 after constructing the 1st pillar 1 in a construction site. For example, fiber reinforced concrete may be filled into the filled concrete portion 80, and the inside of the second pillar 2 may be filled with normal concrete or the like. In this case, since the inside and the outside of the second pillar 2 are partitioned in the vertical direction by the base plate 23, fiber reinforced concrete is placed on the filling concrete portion 80 (outside of the second pillar 2), and Ordinary concrete can be laid inside each other.

  Further, the case where the rib 60 is formed so as to protrude inward from the inner peripheral surface of the bonded steel pipe 50 has been described as an example. However, the present invention is not limited to this, and the rib 60 may be formed so as to protrude outward from the outer peripheral surface of the bonded steel pipe 50.

  Moreover, the case where the 2nd pillar 2 was comprised by the filling steel pipe concrete structure was mentioned as an example, and was demonstrated. However, the present invention is not limited to this, and can also be applied to the case where the second pillar 2 is constructed of steel.

  Moreover, the case where the stress switching part 5 was provided in the first basement was described as an example. However, the present invention is not limited to this, and can be applied to the case where the stress switching unit 5 is provided on another floor below the ground or on the ground floor.

DESCRIPTION OF SYMBOLS 1 ... 1st pillar 2 ... 2nd pillar 2A ... Lower part 5 of 2nd pillar ... Stress switching part 11 ... Column main reinforcement 13 ... First concrete part (concrete part)
50 ... Joined steel pipe (steel pipe)
60 ... rib 70 ... main reinforcement 80 ... filled concrete part 100 ... building

Claims (4)

Columns that join a first column of reinforced concrete having a column part reinforcing bar extending vertically in the concrete part and the concrete part, and a second column of steel structure or filled steel pipe concrete structure arranged above the first column A joining structure of
The first column and the second column are joined via a stress switching unit,
The stress switching part is
A lower portion of the second pillar;
A main bar portion that is disposed on the outer peripheral side of the lower portion of the second column, and that extends continuously from the concrete portion and protrudes in the vertical direction from the concrete portion;
A steel pipe that surrounds all of the main reinforcing bars and that is disposed over the entire length in the vertical direction and is formed in a rectangular tube shape that extends in the vertical direction ;
A filled concrete portion filled in the steel pipe,
A plurality of ribs are formed on the steel pipe so as to protrude from the peripheral surface of the steel pipe and at intervals in the vertical direction, and ribs for suppressing out-of-plane buckling of the steel pipe are formed. To join the pillars.   The said rib is formed over the perimeter of the circumferential direction of the said steel pipe, The joining structure of the columns of Claim 1 characterized by the above-mentioned. The concrete of the said filling concrete part is fiber reinforced concrete, The joining structure of the pillars of Claim 1 or Claim 2 characterized by the above-mentioned.   The building provided with the joining structure of the pillars as described in any one of Claims 1-3.

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