JP2018035637A - Design method for structure for joining columns together, and structure for joining columns together - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a design method for a structure for joining columns together, which can prevent a side wall of a joint steel pipe from causing out-of-plane deformation, even when a horizontal force acts on the joint steel pipe, and the structure for joining the columns together.SOLUTION: Fillet welding makes ribs 37 provided in upper and lower parts of an inner peripheral surface of a side wall except a corner part 39 of a joint steel pipe 31 in such a manner as to protrude inward from the inner peripheral surface. The upper rib 37 of the joint steel pipe 31 has such shape dimensions as to satisfy the following conditional expressions (1)-(5).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for designing a junction structure between columns and a junction structure between columns.

  Conventionally, a composite structure building is known in which reinforced concrete columns and concrete-filled steel pipe columns are joined in a vertical direction, such as columns of different structures are joined together. As such a composite structure building, a lower layer portion having a reinforced concrete column, a boundary layer provided in a height range of one layer disposed above the lower layer portion, and a filled steel pipe concrete disposed above the boundary layer An upper layer portion having a built-in pillar has been proposed (see Patent Document 1 below).

In the boundary layer in the above composite structure building, there is a switching portion (stress switching portion) comprising a joining steel pipe forming the outer shell, a main bar inserted into the joining steel pipe, and concrete filled in the joining steel pipe. Is provided. In order to suppress deformation and out-of-plane buckling of the bonded steel pipe, ribs (bonded steel pipe out-of-plane deformation prevention material) are provided along the inner peripheral surface of the bonded steel pipe at the upper and lower ends of the inner peripheral surface of the bonded steel pipe. It is provided all around.
According to such a configuration, for example, the structure of the upper layer part and the structure of the lower layer part can be switched at the boundary layer of only one basement floor.

JP 2013-181350 A

  In the composite structure building described in Patent Document 1, axial force from above acts on the base plate of the concrete-filled steel pipe column, so that the side surface of the joint steel pipe is pushed out of the plane in the stress switching part. Power works. Furthermore, when a horizontal force is applied during an earthquake, the vicinity of the upper end of the bonded steel pipe is deformed out of plane at the end, and a structure that can suppress this is desired.

  The present invention has been made in view of the above circumstances, and even when a horizontal force is applied, a method for designing a joint structure between columns and columns that can suppress out-of-plane deformation of the upper side surface of the joined steel pipe. It is an object to provide a joint structure.

In order to achieve the above object, the present invention employs the following means.
That is, the method for designing a column-to-column connection structure according to the present invention includes a stress switching between a first column of reinforced concrete and a second column of steel or filled steel tubular concrete disposed above the first column. A method of designing a joining structure between columns that are joined via a portion, wherein the stress switching portion is disposed on an outer peripheral side of a lower portion of the second pillar and a lower portion of the second pillar, A main reinforcing bar extending in the vertical direction from the concrete part, surrounding the main reinforcing part, and a rectangular bonded steel pipe disposed in the vertical direction, and a concrete part filled in the bonded steel pipe, And ribs are provided by fillet welding so that ribs protrude inward from the inner peripheral surface on the upper and lower portions of the inner peripheral surface of the side wall excluding the corners of the bonded steel pipe, and the ribs on the upper portion of the bonded steel pipe The following conditional expressions (1) to (5) Characterized in that a shape dimensioned to foot.

However,
M _y1 : Yield bending moment (N · mm) at the end in the horizontal (plate thickness) direction of the upper part of the bonded steel pipe
M _y2 : Yield bending moment (N · mm) at the center in the horizontal (plate thickness) direction of the upper part of the bonded steel pipe
h _RIB : Length of rib in the vertical direction (mm)
t _p : thickness of the bonded steel pipe (mm)
F: F value of the material of the bonded steel pipe or F value of the material of the rib (N / mm ² )
Q _max : Maximum shear force (N) that can occur in ribs fillet welded to a bonded steel pipe
B _p : width of the bonded steel pipe (mm)
τ _w : degree of shear stress (N / mm ² ) acting on the welded portion between the bonded steel pipe and the rib
S: Safety factor L _n : Length (mm) of the non-welded part (between fillet welds)
L _w : Length of one fillet weld part (mm)
a: Throat thickness of fillet welded part or 0.7s (mm)
s: Leg length of fillet welded part (mm)
t _RIB : Rib thickness (mm).

  Moreover, the column-to-column connection structure according to the present invention includes a first column made of reinforced concrete and a second column made of steel or filled steel pipe concrete arranged above the first column via a stress switching unit. A joined structure of joined columns, wherein the stress switching portion is disposed on the lower side of the second column and on the outer peripheral side of the lower portion of the second column, and extends vertically from the concrete portion of the first column. A projecting and extending main reinforcing bar portion, surrounding the main reinforcing bar portion, and having a rectangular joined steel pipe arranged in the vertical direction in plan view, and a concrete portion filled in the joining steel pipe, The upper and lower portions of the inner peripheral surface of the side wall excluding the corner portion are provided by fillet welding so that the rib protrudes inward from the inner peripheral surface, and the rib at the upper portion of the bonded steel pipe has the following conditional expression: Geometric dimensions that satisfy (6) to (10) Characterized in that it.

However,
M _y1 : Yield bending moment (N · mm) at the end in the horizontal (plate thickness) direction of the upper part of the bonded steel pipe
M _y2 : Yield bending moment (N · mm) at the center in the horizontal (plate thickness) direction of the upper part of the bonded steel pipe
h _RIB : Length of rib in the vertical direction (mm)
t _p : thickness of the bonded steel pipe (mm)
F: F value of the material of the bonded steel pipe or F value of the material of the rib (N / mm ² )
Q _max : Maximum shear force (N) that can occur in ribs fillet welded to a bonded steel pipe
B _p : width of the bonded steel pipe (mm)
τ _w : degree of shear stress (N / mm ² ) acting on the welded portion between the bonded steel pipe and the rib
S: Safety factor L _n : Length (mm) of the non-welded part (between fillet welds)
L _w : Length of one fillet weld part (mm)
a: Throat thickness of fillet welded part or 0.7s (mm)
s: Leg length of fillet welded part (mm)
t _RIB : Rib thickness (mm).

  According to such an invention, the ribs are provided by fillet welding on the upper and lower portions of the inner peripheral surface of the side wall excluding the corner portion of the joining steel pipe having a rectangular shape in plan view of the stress switching portion. Since the corner portion of the bonded steel pipe has high geometrical rigidity and it is not necessary to provide a rib at the corner portion, the rib can be easily formed and joined.

  And the rib of the shape suitable for the joining steel pipe is fillet welded to the inner peripheral surface of the side wall of the joining steel pipe so as to satisfy the conditional expressions (1) to (10) as described above. Out-of-plane deformation of the upper part of the bonded steel pipe at the end when horizontal force is applied is suppressed. Here, it is considered that a horizontal force acts on the upper side wall of the welded steel pipe to which the rib is welded, and yield hinges are formed at three ends of the joined steel pipe at both ends and the central part. It is confirmed that the shear stress acting on the welded portion is less than the allowable stress.

  As a result, according to the present invention, in the joint structure between columns in which out-of-plane deformation is suppressed by welding ribs to the side walls excluding the corners of the rectangular joining steel pipe, the horizontal direction is applied to the joining steel pipe due to an earthquake or the like. Even if a force acts, it is possible to prevent out-of-plane deformation that occurs on the upper side wall of the bonded steel pipe at the end.

In the joint structure between columns according to the present invention, the main reinforcing bars may be connected by a reinforcing bar joint provided at a lower part of the stress switching part.
In the joining structure of the columns configured as described above, the first column, the second column, and the stress switching unit are configured by the precast member, and the upper portion of the first column and the lower portion of the second column are connected by the stress switching unit. At this time, after the upper part of the first pillar and the lower part of the second pillar are arranged at predetermined positions, the main bar portion can be arranged around the lower part of the second pillar, and the work efficiency is good.

  According to the column-to-column connection structure design method and the column-to-column connection structure according to the present invention, even if a horizontal force acts on the stress switching portion where the columns of different structures are bonded to each other, It is possible to prevent out-of-plane deformation on the side wall.

(A) is a schematic sectional drawing which shows the joining structure of the pillars concerning embodiment of this invention, (b) is AA sectional drawing of (a). (A) is a horizontal direction sectional view of a stress switching part, (b) is a stress figure which acts on the side of a joined steel pipe in the BB line of (a). (A) is a horizontal direction sectional view of a stress switching part in the position of a rib, and (b) is a vertical direction sectional view of a stress switching part.

The building which concerns on embodiment of this invention is demonstrated using drawing.
1A and 1B are schematic front views showing a column-to-column junction structure according to an embodiment of the present invention. In the following drawings, in order to make the configuration easy to understand, a portion to be indicated by a broken line may be indicated by a solid line.
As shown in FIG. 1, in the building 10 which concerns on this embodiment, the 1st pillar 11 made from a reinforced concrete is extended to the floor slab 13 of the first basement floor. The second pillar 12 made of filled steel pipe concrete is disposed so as to penetrate the floor slab 14 on the first floor in the vertical direction.

The first pillar 11 and the second pillar 12 are one layer between the floor slab 13 on the first basement floor and the floor slab 14 on the first floor above the ground, and are joined via a stress switching portion 15 (to be described later). Joint structure). The first pillar 11 is a second-floor pillar, and the lower portions of the stress switching unit 15 and the second pillar 12 are first-floor pillars.
In the present embodiment, the first pillar 11, the second pillar 12, and the stress switching unit 15 may each be composed of a precast concrete member.

(First pillar)
Although the detailed illustration of the first pillar 11 is omitted, for example, a plurality of column main bars that are arranged at predetermined intervals in the horizontal direction and extend in the vertical direction, and a plurality of strip bars that bundle the plurality of column main bars are planar. The first concrete portion 17 filled in a substantially rectangular shape is covered and disposed.
The plurality of column main bars are arranged along the outer peripheral surface of the first concrete portion 17 and extend upward, and a rebar joint 19 is connected to the upper end. The reinforcing bar joint 19 that protrudes upward from the floor slab 13 on the first basement floor is connected to a main reinforcing bar part 21 that constitutes a stress switching part 15 described later.
In the present embodiment, the column main bars of the first column 11 are connected to the reinforcing bar joint 19, and the main bar part 21 of the stress switching unit 15 protrudes upward from the reinforcing bar joint 19.

(Second pillar)
The second column 12 includes a rectangular tubular steel tube 23 and a second concrete portion 25 filled in the rectangular steel tube 23.
The second column 12 is arranged inside the first column 11 in plan view so that each side of the second column 12 is parallel to each side of the first column 11.

  A base plate 27 having a substantially rectangular shape in plan view is provided at the lower end of the square steel pipe 23. The outline of the base plate 27 in plan view is larger than the outline of the square steel pipe 23 in plan view and smaller than the outline of the first column 11 in plan view. Further, a substantially circular concrete placement port 29 penetrating in the vertical direction is formed in the substantially central portion of the base plate 27 in plan view so as to be used for placing concrete.

(Stress switching part)
The stress switching unit 15 is arranged in a single layer between the floor slab 13 on the first basement floor and the floor slab 14 on the first floor above ground.
The stress switching unit 15 surrounds the main bar part 21, a main bar part 21 that is disposed on the outer peripheral side of the lower part of the second column 12, and extends in a vertical direction from the first concrete part 17. In addition, a joining steel pipe 31 having a rectangular shape in plan view and a concrete portion 33 filled in the joining steel pipe 31 are provided.

  The lower part of the second pillar 12 is a part of the second pillar 12 that extends downward from the floor slab 14 on the first floor above the ground. The main reinforcement portion 21 is a portion that is connected by a reinforcing bar joint 19 embedded in the lower portion of the stress switching portion 15, protrudes upward from the upper surface of the first concrete portion 17, and extends in the vertical direction. The main bar portion 21 is disposed so as to surround the outer peripheral side of the lower portion of the second column 12 and extends higher than the base plate 27 at the lower end portion of the second column 12.

The joining steel pipe 31 is a square tubular steel pipe extending in the vertical direction. The bonded steel pipe 31 surrounds the lower portion of the main reinforcing bar portion 21 and the second column 12 and is disposed over the entire length of the stress switching portion 15 in the vertical direction.
The outer shape in plan view of the bonded steel pipe 31 is substantially the same as the outer shape in plan view of the first column 11. The bonded steel pipe 31 is disposed on the upper side of the first column 11 so that the outer peripheral surface thereof is flush with the outer peripheral surface of the first column 11.
Further, the outer shape in plan view of the bonded steel pipe 31 is larger than the outer shape in plan view of the second column 12, and the lower part of the second column 12 is disposed inside the bonded steel pipe 31.

The bonded steel pipe 31 is disposed from the upper end portion of the first column 11 to the lower portion of the second column 12.
Ribs 37 are provided on the upper and lower portions of the bonded steel pipe 31 so as to protrude inward from the inner peripheral surface of the side wall 35 of the bonded steel pipe 31. The rib 37 is provided on each of the inner peripheral surfaces of the four side walls 35 excluding the corner portion 39 of the bonded steel pipe 31.
In this embodiment, the rib 37 is formed in a substantially rectangular parallelepiped plate shape, and has sufficient strength against bending and shearing caused by a horizontal force acting on the upper portion of the stress switching portion 15 as will be described later. Yes.
The ribs 37 are provided on the inner peripheral surface of the side wall 35 of the bonded steel pipe 31 and are not provided at the corners 39 of the bonded steel pipe 31 in plan view. In addition, as shown in FIG. 1A, the corner portion 39 may be formed (curved) so as to be rounded in a plan view by adopting, for example, a cold-formed square steel pipe, or four pieces. These flat steel plates may be formed at a right angle by combining them into a rectangular tube shape.

The upper rib 37 of the bonded steel pipe 31 is provided so that the position of the upper end of the rib 37 is aligned with the upper end of the bonded steel pipe 31. The lower rib 37 of the bonded steel pipe 31 is provided so that the position of the lower end of the rib 37 is aligned with the lower end of the bonded steel pipe 31. In addition, the rib 37 should just be provided in the upper part and the lower part of the joining steel pipe 31, respectively, and may be provided below the upper end part and above the lower end part.
These ribs 37, against a bearing capacity reaction force of Input shear force Q _D acting on the joined steel tube 31 by borrowing shear force Q _D from the second pillar 12, the upper portion of the joining steel pipe 31 is out-of-plane deformation It has a function to prevent this.

  The concrete portion 33 is concrete that is filled inside the bonded steel pipe 31 and outside the rectangular steel pipe 23 of the second column 12 over the entire length of the bonded steel pipe 31. In this embodiment, fiber reinforced concrete is adopted, but ordinary concrete may be used. The fiber reinforced concrete is a concrete material mixed with synthetic fiber, steel fiber, or the like.

In such a joint structure between columns, the rib 37 is designed as follows.
FIG. 2A is a horizontal sectional view of the stress switching portion, and FIG. 2B is a stress diagram acting on the side surface of the bonded steel pipe along the line BB in FIG. 3A is a horizontal cross-sectional view of the stress switching unit at the rib position, and FIG. 3B is a vertical cross-sectional view of the stress switching unit.
In this embodiment, as shown in FIG. 2A, a horizontal force acts on the stress switching portion 15, and a horizontal force acts on the side wall 35 on one side of the bonded steel pipe 31. As shown in FIG. 2B, first, let us consider a state in which both ends and the center of the side wall 35 on one side of the bonded steel pipe 31 reach the yield strength due to the horizontal force, and yield hinges are formed at the three locations.

但し、
Ｚ_ｚ１： 接合鋼管３１の上部の水平（板厚）方向端部における鉛直方向軸周りの断面係数（ｍｍ^３）
Ｍ_ｙ１： 接合鋼管３１の上部の水平（板厚）方向端部の降伏曲げモーメント（Ｎ・ｍｍ）
Ｆ： 接合鋼管３１の材料のＦ値またはリブ３７の材料のＦ値（Ｎ／ｍｍ^２）
ｈ_ＲＩＢ： リブ３７の鉛直方向の長さ（ｍｍ）
ｔ_ｐ： 接合鋼管３１の厚さ（ｍｍ） In this case, the yield bending moment M _y1 at the end portion in the horizontal (plate thickness) direction in the vicinity of the corner portion 39 of the bonded steel pipe 31 is expressed by Expression (11).

However,
Z _z1 : Section modulus (mm ³ ) around the vertical axis at the end in the horizontal (plate thickness) direction of the upper part of the bonded steel pipe 31
M _y1 : Yield bending moment (N · mm) at the end in the horizontal (plate thickness) direction of the upper part of the bonded steel pipe 31
F: F value of the material of the bonded steel pipe 31 or F value of the material of the rib 37 (N / mm ² )
h _RIB : Length of rib 37 in the vertical direction (mm)
t _p : Thickness (mm) of the bonded steel pipe 31

但し、
Ｚ_ｚ２： 接合鋼管３１の上部の水平（板厚）方向中央部における鉛直方向軸周りの断面係数（ｍｍ^３）
Ｍ_ｙ２： 接合鋼管３１の上部の水平（板厚）方向中央部の降伏曲げモーメント（Ｎ・ｍｍ）
Ｆ： 接合鋼管３１の材料のＦ値またはリブ３７の材料のＦ値（Ｎ／ｍｍ^２）
ｈ_ＲＩＢ： リブ３７の鉛直方向の長さ（ｍｍ）
ｔ_ＲＩＢ： リブ３７の厚さ（ｍｍ）
ｔ_ｐ： 接合鋼管の厚さ（ｍｍ） On the other hand, the yield bending moment _{My2 at the} central portion in the horizontal (plate thickness) direction of the upper portion of the bonded steel pipe 31 is expressed by Expression (12).

However,
Z _z2 : Section modulus (mm ³ ) around the vertical axis at the center in the horizontal (plate thickness) direction of the upper part of the bonded steel pipe 31
M _y2 : Yield bending moment (N · mm) at the center in the horizontal (plate thickness) direction of the upper part of the bonded steel pipe 31
F: F value of the material of the bonded steel pipe 31 or F value of the material of the rib 37 (N / mm ² )
h _RIB : Length of rib 37 in the vertical direction (mm)
t _RIB : thickness of rib 37 (mm)
t _p : thickness of the bonded steel pipe (mm)

但し、
Ｑ_ｍａｘ：接合鋼管に隅肉溶接されたリブに生じ得る最大せん断力（Ｎ）
Ｍ_ｙ１： 接合鋼管３１の上部の水平（板厚）方向端部の降伏曲げモーメント（Ｎ・ｍｍ）
Ｍ_ｙ２： 接合鋼管３１の上部水平方（板厚）向中央部の降伏曲げモーメント（Ｎ・ｍｍ）
Ｂ_ｐ： 接合鋼管３１の幅（ｍｍ）
ｔ_ｐ： 接合鋼管３１の厚さ（ｍｍ） From the equations (11) and (12), the maximum shearing force Q _max generated on the side wall 35 of the bonded steel pipe 31 in a state where the rib 37 is intermittently fillet welded is as shown in the equation (13).

However,
Q _max : Maximum shear force (N) that can occur in ribs fillet welded to a bonded steel pipe
M _y1 : Yield bending moment (N · mm) at the end in the horizontal (plate thickness) direction of the upper part of the bonded steel pipe 31
M _y2 : Yield bending moment (N · mm) at the center in the upper horizontal direction (sheet thickness) of the bonded steel pipe 31
B _p : width (mm) of the bonded steel pipe 31
t _p : Thickness (mm) of the bonded steel pipe 31

但し、
Ｓ： 安全率
τ_ｗ： 接合鋼管３１とリブ３７との溶接部分に作用するせん断応力度（Ｎ／ｍｍ^２）
Ｑ_ｍａｘ：接合鋼管に隅肉溶接されたリブに生じ得る最大せん断力（Ｎ）
Ｌ_ｎ： 非溶接部分（隅肉溶接部分間）の長さ（ｍｍ）
Ｌ_ｗ： 隅肉溶接部分１カ所の長さ（ｍｍ）
ａ： 隅肉溶接部分ののど厚又は０．７ｓ（ｍｍ）
ｓ： 隅肉溶接部分の脚長（ｍｍ）
ｈ_ＲＩＢ： リブ３７の鉛直方向の長さ（ｍｍ）
ｔ_ＲＩＢ： リブ３７の厚さ（ｍｍ）
ｔ_ｐ： 接合鋼管３１の厚さ（ｍｍ） The maximum shear force Q _max is used in consideration of the safety factor S, and the shear stress degree τ _w acting on the intermittent fillet weld portion between the bonded steel pipe 31 and the rib 37 can be calculated as shown in Equation (14). it can. In the present embodiment, the safety factor S may be set to 1.5, for example.

However,
S: Safety factor τ _w : Shear stress level (N / mm ² ) acting on the welded portion between the bonded steel pipe 31 and the rib 37
Q _max : Maximum shear force (N) that can occur in ribs fillet welded to a bonded steel pipe
L _n : Length (mm) of non-welded part (between fillet welds)
L _w : Length of one fillet weld part (mm)
a: Throat thickness of fillet welded part or 0.7s (mm)
s: Leg length of fillet welded part (mm)
h _RIB : Length of rib 37 in the vertical direction (mm)
t _RIB : thickness of rib 37 (mm)
t _p : Thickness (mm) of the bonded steel pipe 31

但し、
τ_ｗ： 接合鋼管３１とリブ３７との溶接部分に作用するせん断応力度（Ｎ／ｍｍ^２）
Ｆ： 接合鋼管３１の材料のＦ値またはリブ３７の材料のＦ値（Ｎ／ｍｍ^２） The length L _n, the length L _w of the fillet _weld, leg length s, fillet weld fillet welded portion of the non-welded parts required intermittent fillet weld between the bonding steel pipe 31 and the ribs 37 The throat thickness a is determined so as to satisfy equation (15). As a result, a desired joining structure between the columns can be realized.

However,
τ _w : Shear stress level (N / mm ² ) acting on the welded portion between the bonded steel pipe 31 and the rib 37
F: F value of the material of the bonded steel pipe 31 or F value of the material of the rib 37 (N / mm ² )

  According to the column-to-column joining structure and the design method as described above, the upper and lower portions of the inner peripheral surface of the side wall 35 excluding the corner 39 are attached to the joint steel pipe 31 having a rectangular shape in plan view of the stress switching portion 15. Ribs 37 are provided by fillet welding. Since the corner portion 39 of the joining steel pipe 31 has high geometrical rigidity and it is not necessary to provide the rib 37 on the corner portion 39, the rib 37 can be easily formed and joined.

  And the rib 37 of the shape suitable for the joining steel pipe 31 is fillet welded to the internal peripheral surface of the side wall of the joining steel pipe 31 so that the above conditional expressions may be satisfy | filled. Thereby, the out-of-plane deformation | transformation of the upper part of the joining steel pipe 31 at the time of final time when the force of a horizontal direction acts on the stress switching part 15 by an earthquake etc. is suppressed. Here, it is considered that a horizontal force acts on the upper side wall 35 of the bonded steel pipe 31 to which the ribs 37 are welded, and yield hinges are formed at three positions, both ends and the center of the bonded steel pipe 31. It is confirmed that the degree of shear stress acting on the welded portion 41 between the rib 37 and the rib 37 is less than the allowable stress level.

  As a result, it is possible to suppress the out-of-plane deformation of the upper portion of the bonded steel pipe 31 by welding the rib 37 to the side wall 35 excluding the corner portion 39 of the bonded steel pipe 31 having a rectangular shape in plan view. Even if a horizontal force is applied to 31, it is possible to prevent out-of-plane deformation occurring in the upper side wall 35 of the bonded steel pipe 31 at the end.

  In the joint structure between precast columns, the main reinforcing bars 21 are connected by a reinforcing bar joint 19 embedded in the lower part of the stress switching part 15. For this reason, when connecting the upper part of the 1st pillar 11 and the lower part of the 2nd pillar 12 by the stress switching part 15, after arrange | positioning the upper part of the 1st pillar 11 and the lower part of the 2nd pillar 12 in a predetermined position, The main muscle portion 21 can be arranged around the lower part of the two pillars 12 and the work efficiency is good.

  The various shapes and combinations of the constituent members shown in the above-described embodiments are merely 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, the case where the second pillar 12 is made of a filled steel pipe concrete structure has been described as an example. However, the present invention is not limited to this, and can also be applied to the case where the second pillar 12 is made of steel.

  In addition, the case where the first pillar 11 is provided on the second basement and the stress switching unit 15 and the second pillar 12 are provided on the first basement has been described as an example. However, the present invention is not limited to this, and can also be applied to the case where the first pillar 11, the stress switching unit 15, and the second pillar 12 are provided on the other floors and the ground floor.

DESCRIPTION OF SYMBOLS 10 ... Building 11 ... 1st pillar 12 ... 2nd pillar 13 ... Floor slab 14 on the first basement floor ... Floor slab 15 on the ground first floor ... Stress switching part 17 ... First concrete part 19 ... Reinforcement joint 21 ... Main reinforcement part 23 ... Square steel pipe 25 ... Second concrete part 27 ... Base plate 29 ... Concrete placement port 31 ... Joint steel pipe 33 ... Concrete part 35 ... Side wall 37 ... Rib 39 ... Corner part 41 ... Welded part

Claims (3)

This is a design method of a joint structure between columns in which a first column of reinforced concrete and a second column of steel structure or filled steel pipe concrete constructed above the first column are joined via a stress switching part. And
The stress switching part is
A lower portion of the second pillar;
A main reinforcing bar portion disposed on the outer peripheral side of the lower portion of the second pillar and extending in a vertical direction from the concrete portion of the first pillar;
While encircling the main reinforcing bar, a rectangular bonded steel pipe arranged in the vertical direction in plan view;
A concrete portion filled in the bonded steel pipe,
The upper and lower portions of the inner peripheral surface of the side wall excluding the corner portion of the bonded steel pipe are provided by fillet welding so that ribs protrude inward from the inner peripheral surface, and the rib at the upper portion of the bonded steel pipe is A method for designing a joining structure between columns, characterized in that the dimensions satisfy the following conditional expressions (1) to (5).

However,
M _y1 : Yield bending moment (N · mm) at the end in the horizontal (plate thickness) direction of the upper part of the bonded steel pipe
M _y2 : Yield bending moment (N · mm) at the center in the horizontal (plate thickness) direction of the upper part of the bonded steel pipe
h _RIB : Length of rib in the vertical direction (mm)
t _p : thickness of the bonded steel pipe (mm)
F: F value of the material of the bonded steel pipe or F value of the material of the rib (N / mm ² )
Q _max : Maximum shear force (N) that can occur in ribs fillet welded to a bonded steel pipe
B _p : width of the bonded steel pipe (mm)
τ _w : degree of shear stress (N / mm ² ) acting on the welded portion between the bonded steel pipe and the rib
S: Safety factor L _n : Length (mm) of the non-welded part (between fillet welds)
L _w : Length of one fillet weld part (mm)
a: Throat thickness of fillet welded part or 0.7s (mm)
s: Leg length of fillet welded part (mm)
t _RIB : Rib thickness (mm). The first column of the reinforced concrete structure and the second column of the steel structure or the filled steel pipe concrete structure disposed above the first column are joined structures of the columns joined via the stress switching part,
The stress switching part is
A lower portion of the second pillar;
A main reinforcing bar portion disposed on the outer peripheral side of the lower portion of the second pillar and extending in a vertical direction from the concrete portion of the first pillar;
While encircling the main reinforcing bar, a rectangular bonded steel pipe arranged in the vertical direction in plan view;
A concrete portion filled in the bonded steel pipe,
The upper and lower portions of the inner peripheral surface of the side wall excluding the corner portion of the bonded steel pipe are provided by fillet welding so that ribs protrude inward from the inner peripheral surface, and the rib at the upper portion of the bonded steel pipe is A joining structure between columns, characterized in that the dimensions satisfy the following conditional expressions (6) to (10).

However,
M _y1 : Yield bending moment (N · mm) at the end in the horizontal (plate thickness) direction of the upper part of the bonded steel pipe
M _y2 : Yield bending moment (N · mm) at the center in the horizontal (plate thickness) direction of the upper part of the bonded steel pipe
h _RIB : Length of rib in the vertical direction (mm)
t _p : thickness of the bonded steel pipe (mm)
F: F value of the material of the bonded steel pipe or F value of the material of the rib (N / mm ² )
Q _max : Maximum shear force (N) that can occur in ribs fillet welded to a bonded steel pipe
B _p : width of the bonded steel pipe (mm)
τ _w : degree of shear stress (N / mm ² ) acting on the welded portion between the bonded steel pipe and the rib
S: Safety factor L _n : Length (mm) of the non-welded part (between fillet welds)
L _w : Length of one fillet weld part (mm)
a: Throat thickness of fillet welded part or 0.7s (mm)
s: Leg length of fillet welded part (mm)
t _RIB : Rib thickness (mm).   The joint structure between columns according to claim 2, wherein the main reinforcing bars are connected by a reinforcing bar joint provided at a lower part of the stress switching part.

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