JP2000282577A - Method for obtaining proof stress of beam-column connection section in steel-pipe column - Google Patents

Abstract

PROBLEM TO BE SOLVED: To present the design method of a beam-column connection section in a steel-pipe column presenting a simple and general-purpose method in which the proof stress of the beam-column connection section in the steel-pipe column is obtained, keeping the fixed accuracy of the proof stress of the beam-column connection section of the steel-pipe column and using a method in which such proof stress is obtained. SOLUTION: Each component is calculated by proof stress evaluation formula by an analytical technique, assuming disintegration into the two flow components of a flow to a column of beam-flange axial force, and the sum of the components is evaluated as the proof stress of a connection section. The flow (front shear force) P1 of the component 1 mainly represents the flow of force that a steel-pipe wall surface near to a section on which a beam is mounted is bent and deflected and transmitted in the steel-pipe axial direction, and the flow (ring proof strength) P2 of the components 2 represents the flow of force transmitted in the ring circumferential direction by the bending of a ring and a steel-pipe plate near to the ring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for determining the strength of a column-beam joint in a steel pipe column, and more particularly to a hollow circular steel pipe column with a ring diaphragm (hereinafter simply referred to as "hollow steel pipe column") shown in FIG. , A hollow steel tube column with a thicker joint with the beam shown in FIG.
2B), or a special case of a ring-integrated type, in which the beam flange is attached with vertical eccentricity and horizontal eccentricity to a non-thickened hollow circular steel pipe column shown in FIG. About the method.

[0002]

2. Description of the Related Art Conventionally, for example, a column-beam joint strength of a steel pipe column with a ring diaphragm is evaluated by a calculation formula based on a tensile test as shown in FIG. It was determined by applying to each beam flange. The obtained values are regarded as the local proof stresses under the tensile load and the compressive load, and the relationship between the beam flanges has been neglected.

[0003]

However, this calculation formula is an empirical formula derived from a series of tensile test results, and has a limited application range, and is generally assumed to have a strength calculation in an earthquake region. However, it cannot be said that the case where a tensile force and a compressive force act on the beam flanges on both sides of the steel pipe as shown in FIG. In addition, since it is an empirical formula, the designer cannot recognize the basis of the calculation, and it is impossible to apply to a special case out of the application range specified by the experiment. Furthermore, a design method of the above-mentioned purpose has not been proposed for a case where a conventional beam flange is attached with vertical eccentricity and horizontal eccentricity. The prior art has the above-mentioned problems.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a simple and versatile steel pipe column while maintaining a constant accuracy of the column-beam joint strength of the steel pipe column. The present invention is to present a method for obtaining the proof stress of the beam-to-column joint in the above, and to present a design method of the beam-to-column joint in the steel pipe column using the method for obtaining the proof stress.

[0005]

SUMMARY OF THE INVENTION The present invention has the following arrangement to solve the above-mentioned problems. The gist of the invention according to claim 1 is that the beam flange is attached to a hollow circular steel tubular column with a ring diaphragm or a concrete-filled circular steel tubular column with a ring diaphragm so that the beam flange is vertically eccentric to the ring diaphragm. A method for determining the proof stress of a joint portion, in which a flow component (P ₁ ) of a force transmitted by bending deformation of a steel pipe wall near a beam is attached and transmitted in a circumferential direction by bending of a ring and a steel pipe plate near the ring. The gist of the invention according to claim 2 is a method for determining the proof stress of a beam-column joint portion of a steel pipe column from the sum of the flow component (P ₂ ) of the flow force and the hollow circular steel pipe column with a ring diaphragm or concrete filling with a ring diaphragm. Strength of beam-column joints of steel pipe columns when beam flanges are attached to circular steel pipe columns with eccentricity perpendicular to the ring diaphragm The flow component (P ₁ ) of the force transmitted by bending deformation of the steel pipe wall near the beam and the flow of force transmitted in the circumferential direction due to the bending of the ring and the steel pipe sheet near the ring decomposed into a component (P _2), the said components (P _2), consists in a method for determining the strength of beam-column joint portion in the steel pipe column.
The gist of the invention according to claim 3 is that, when a beam flange receiving a symmetric load is attached to a hollow circular steel pipe column with a ring diaphragm with horizontal eccentricity with respect to the ring diaphragm, the strength of the column-beam joint portion in the steel pipe column is reduced. A flow component of the force transmitted by bending deformation of the steel pipe wall near the beam attachment (P ₁ ) and a flow component of the force transmitted in the circumferential direction by bending of the ring and the steel pipe sheet near the ring The present invention is based on the method of obtaining the proof stress of the beam-column joint of the steel pipe column from the sum of (P ₂ ). The gist of the invention according to claim 4 is that, when a beam flange receiving a symmetrical load is attached to a hollow circular steel tubular column with a ring diaphragm with horizontal eccentricity with respect to the ring diaphragm, the strength of the column-beam joint portion in the steel tubular column is reduced. A flow component (P ₁ ) of the force transmitted by bending and deforming the steel pipe wall near the beam.
If, decomposed into the force flow component transmitted by up song steel plate ring and the ring near the peripheral direction (P _2), the said components (P _2), determine the strength of beam-column joint portion in the steel pipe column Be in the way. The gist of the invention according to claim 5 is that the bearing strength of the beam-column joint portion of the steel pipe column when the beam flange subjected to the antisymmetric load is attached to the hollow circular steel pipe column with the ring diaphragm with horizontal eccentricity with respect to the ring diaphragm. The flow component (P ₁ ) of the force transmitted by bending deformation of the steel pipe wall near the beam and the flow of force transmitted in the circumferential direction due to the bending of the ring and the steel pipe sheet near the ring There is a method of obtaining the proof stress of the beam-column joint portion in the steel pipe column from the sum with the component (P ₂ ). The gist of the invention according to claim 6 is that the bearing strength of the column-beam joint portion of the steel pipe column when the beam flange receiving the antisymmetric load is attached to the hollow circular steel pipe column with the ring diaphragm with horizontal eccentricity with respect to the ring diaphragm. The flow component (P ₁ ) of the force transmitted by bending deformation of the steel pipe wall near the beam and the flow of force transmitted in the circumferential direction due to the bending of the ring and the steel pipe sheet near the ring decomposed into a component (P _2), the said components (P _2), consists in a method for determining the strength of beam-column joint portion in the steel pipe column. The gist of the invention according to claim 7 is that a beam flange receiving a unidirectional load is attached to a hollow circular steel tubular column with a ring diaphragm with horizontal eccentricity with respect to the ring diaphragm. The flow component (P ₁ ) of the force transmitted by bending deformation of the steel pipe wall near the beam and the flow of force transmitted in the circumferential direction due to the bending of the ring and the steel pipe sheet near the ring From the sum with the component (P ₂ ),
The present invention consists in a method for determining the strength of a beam-column joint in a steel pipe column. The gist of the invention according to claim 8 is that a beam flange receiving a unidirectional load is attached to a hollow circular steel tubular column with a ring diaphragm with horizontal eccentricity with respect to the ring diaphragm. The flow component (P ₁ ) of the force transmitted by bending deformation of the steel pipe wall near the beam and the flow of force transmitted in the circumferential direction due to the bending of the ring and the steel pipe sheet near the ring decomposed into a component (P _2), the said components (P _2), consists in a method for determining the strength of beam-column joint portion in the steel pipe column. The gist of the invention according to claim 9 is a method for determining the strength of a column-beam joint portion of a steel pipe column when the beam flange is attached to a concrete-filled circular steel pipe column with a ring diaphragm with horizontal eccentricity with respect to the ring diaphragm. there are, the force of the flow component which is deformed bending steel wall in the vicinity of the beams attach transmission (P _1), the force of the flow component which is transmitted by the bending of a steel pipe plate ring and the ring near the peripheral direction (P ₂ ) And the method for determining the strength of the beam-column joint in the steel pipe column. The gist of the invention according to claim 10 is a method for determining the strength of a column-beam joint portion of a steel pipe column when a beam flange is attached to a concrete-filled circular steel pipe column with a ring diaphragm with horizontal eccentricity with respect to the ring diaphragm. there are, the force of the flow component which is deformed bending steel wall in the vicinity of the beams attach transmission (P _1), the force of the flow component which is transmitted by the bending of a steel pipe plate ring and the ring near the peripheral direction (P ₂ ) And the method for determining the proof stress of the beam-column joint of the steel pipe column from the component (P ₂ ).
The gist of the invention according to claim 11 is that a beam flange receiving a unidirectional load is attached to a hollow circular steel pipe column with a partial ring diaphragm with horizontal eccentricity with respect to the ring diaphragm. This is a method for determining the proof stress, in which the flow component (P ₁ ) of the force transmitted by bending deformation of the steel pipe wall near the beam and the force transmitted in the circumferential direction due to the bending of the ring and the steel pipe sheet near the ring. There is a method for obtaining the proof stress of the beam-column joint portion in the steel pipe column from the sum with the flow component (P ₂ ). The gist of the invention according to claim 12 is that a hollow circular steel tubular column with a partial ring diaphragm includes:
A method for determining the strength of a beam-column joint in a steel pipe column when a beam flange subjected to a unidirectional load is attached with horizontal eccentricity to the ring diaphragm. the force of the flow component (P ₁₎ that is, decomposed into the force flow component transmitted by up song steel plate ring and the ring near the peripheral direction (P _2), the said components (P _2), the steel pipe It is in the method of obtaining the strength of the beam-column joint in the column. The gist of the invention according to claim 13 is further characterized in that the beam flange is attached to the ring diaphragm with a vertical eccentricity, and the beam and column in a steel pipe column according to any of claims 3 to 12. The present invention resides in a method for determining the proof stress of a joint. Claim 1
The gist of the invention described in claim 4 is that the P ₁ is obtained by the following formula.
7, 9, 11, or 13, which is a method for determining the strength of a beam-column joint in a steel pipe column.

(Equation 5) The gist of the invention according to claim 15 resides in the method for determining the strength of a beam-column joint in a steel pipe column according to claim 14, wherein the S is determined by the following equation.

(Equation 9) Summary of the Invention of claim 16, the P ₂ are as defined in any one of claims 1 to 15, characterized in that it is determined by the formula set forth below, determine the strength of beam-column joint portion in the steel pipe column Be in the way. Here, X ₁ , X ₂ , X
₃ , X ₄ and X ₅ are coefficients.

(Equation 15) ,

(Equation 16) ,as well as

[Equation 17] The gist of the invention according to claim 17 is that the effective width α of the steel pipe portion is obtained by the following formula: The method for obtaining the proof stress of a beam-column joint portion of a steel pipe column according to claim 16. Exists.

(Equation 10) The gist of the invention according to claim 18 is that the effective width α of the steel pipe portion is obtained by the following formula, and the yield strength of the beam-column joint portion in the steel pipe column is obtained. Be in the way.

[Equation 11] The gist of the invention according to claim 19 is that, in the steel pipe column, the steel tube column is a steel tube column having a thickened joint portion with the beam. The method is to determine the proof stress of the beam-column joint at Claim 2
The gist of the present invention resides in a method of designing a beam-column joint in a steel pipe column using the method for determining proof stress according to claims 1 to 19. The gist of the invention described in claim 21 resides in a recording medium in which a program capable of executing the method for determining the strength of a beam-column joint in a steel pipe column according to any one of claims 1 to 19 is recorded. The gist of the invention according to claim 22 resides in a recording medium in which a program capable of executing the method for designing a beam-column joint in a steel pipe column according to claim 20 is recorded. The gist of the invention according to claim 23 resides in a structure constructed by the method of designing a beam-column joint of a steel pipe column according to claim 20. In the first or second aspect of the invention, the “ring diaphragm” includes the “partial ring” described in the embodiment. In the invention according to any one of claims 3 to 10, the "ring diaphragm" includes the "ring integrated type" described in the embodiment.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. Assuming that the flow of the beam flange axial force to the column is decomposed into two flow components as shown in FIGS. 6 (A) and 6 (B), the strength of each component is determined by an analytical method. It is calculated by an evaluation formula, and the sum is evaluated as the proof stress of the joint.

[0007] As shown in FIG.
"Front shear force" hereinafter) P ₁ is the force of the flow is mainly transmitted to the deformed axial direction of the steel pipe bending steel tube wall in the vicinity of the beam is Toritsui flow component 2 (hereinafter, referred to as "ring strength") P ₂ by bending of a steel pipe plate ring and the ring near the flow of force transmitted to the ring circumferential direction.

Accordingly, the proof stress P of the joint transmitted by the beam flange is the sum of the two,

[0009]

(Equation 1)

The long-term allowable strength P _A used in the strength design method
(Long term), short term allowable strength P _A (short term) and maximum strength P
u is

[0011]

(Equation 2)

[0012]

(Equation 3)

[0013]

(Equation 4)

It is assumed that

In the design, it is sufficient that the flange axial force obtained from the structural analysis does not exceed the long-term allowable strength, short-term allowable strength or maximum strength corresponding to each load.

The front shear force P ₁ is obtained from the cylindrical shell theory. The equation for calculating P ₁ is given as follows regardless of the load state.

[0017]

(Equation 5)

Here,

[0019]

(Equation 6)

[0020]

(Equation 7)

[0021]

(Equation 8)

The effective circumference S (see FIG. 8) was set as shown in equation (9) from the results of experiments and finite element analysis (hereinafter referred to as FEM).

[0023]

(Equation 9)

The ring strength P ₂ is, T-section, including effective width α of the steel pipe portion shown in FIG. 9 (hereinafter, referred to as "ring form") arch / ring effective radius Re consisting Arch / ring skeleton Theory Is determined by applying Here, if the beam flanges attach with horizontal eccentricity e _h, flange axial force, be regarded as two points concentrated load acting acting position [psi _A, the [psi _B as shown in FIG. 11.

The effective width α is obtained from the experimental and FEM results as (1
(0) or (11) was set.

[0026]

(Equation 10)

However, the effective width α of the ring integrated type is

[0028]

[Equation 11]

The effective radius Re is

[0030]

(Equation 12)

Where g is

[0032]

(Equation 13)

In the case where there is no horizontal eccentricity shown in FIG. 10, the operating position の of the two-point concentrated load is (1) from the experiment and the FEM result.
It was set as shown in equation 8).

[0034]

[Equation 14]

However, as shown in FIG.
_When the beam flange is joined with _h , the acting position of the two-point concentrated load is expressed by the following equation using the amount of horizontal eccentricity. However, it is assumed that e _k <0.5 (D−B _f ).

[0036]

(Equation 15)

[0037] _However, when the _{B f -H s ≦ H s /} 2 is,

[0038]

(Equation 16)

It is assumed that

Ring strength P₂Is the total plastic strength of the ring
M_p, N_p, Q_p, M_θpAnd T _RpFor
Moment M, axial force N, shearing force at the examination point
Q, weak axis bending moment M_θAnd torque T_RPlastic strip
Condition:

[0041]

[Equation 17]

Is obtained by applying

The total plastic strength M _p , N _p , Q _p ,
M _θp and _TRp are calculated according to the following formulas:

[0044]

(Equation 18)

[0045]

[Equation 19]

[0046]

(Equation 20)

M _θp and T _Rp are regarded as valid only for the ring portion (ignoring the steel pipe portion), and are respectively (2
It is determined by the expression 6) and the expressions (27) and (28).

[0048]

(Equation 21)

[0049]

(Equation 22)

In the ring integrated type, the effective width α is set by equation (11), and H _s = 0, T _s = t _f and t _c = t _p are substituted in equations (22) to (28). Ask.

The bending moment M necessary ring body in the calculation of P _2, the axial force N, shear force Q, plane bending moment M _theta and torque T _{R (hereinafter,} referred to as "cross-sectional strength of the ring member")
Indicates the load condition, whether or not concrete is filled, whether or not there is eccentricity,
The calculation method differs depending on the shape of the ring and the like, and is classified into the following cases.

(1) Hollow steel tube column under symmetric load (2) Hollow steel tube column under reverse symmetric load (3) Hollow steel tube column under unidirectional load (4) CFT (5) Partial ring (under unidirectional load) hollow steel tube column

[0053] Among the cross-sectional strength of the ring member, the weak axial bending moment M _theta and torque T _R is common to all cases, occurs when a vertical eccentricity. That is, FIG.
As shown in for beam flange ring, trims with a vertical eccentric e _v, when acting on the angle at which the concentrated load P _2/2 is formed between the flange center axis [psi (see FIG. 14), the addition of axial the moment e _v P _2/2, the angle theta, is decomposed in the circumferential direction and the radial direction, the weak axial bending moment M _theta and the torque T _R becomes acting on the ring member, respectively (2
It is expressed by the expressions 9) and (30).

[0054]

(Equation 23)

[0055]

(Equation 24)

On the other hand, the bending moment M, the axial force N, and the shearing force Q among the sectional forces of the ring body are derived by the arch / ring framework theory by assuming boundary conditions corresponding to each case.

[0057] When there is no horizontal offset has been presented for the inventor's prior application, the bending moment M when the load P ₂ trims are beam flange with a horizontal eccentricity is applied, axial force N, shear force Q Regarding the calculation method, regarding (1) to (5),
Each is described.

(1) Hollow steel pipe column at the time of symmetrical load When a symmetrical load as shown in FIG. 15 is applied to the hollow steel pipe column, it is considered as a problem that a four-point concentrated load acts on the annular ring as shown in FIG. . Here, from the symmetry, φ = π
−ψ.

In FIG. 16, if the angle between the x-axis and θ is defined as θ (point B in the figure is zero), the angle θ
Moment M, axial force N and shear force Q at the point
Is expressed by equation (31) using the ring proof stress P ₂ .
However, the annular ring is assumed to have uniform rigidity all around, and only deformation is considered, and deformation due to axial force and shear force is ignored.

[0060]

(Equation 25)

[0061] As shown in FIG. 17, the beam in the horizontal direction _{e h}
Only decentered state is joined to the ring diaphragms, concentrated four points in a circular ring as shown in Figure 18 the load P _2/2
Can be considered as acting on the angles ψ _A , ψ _B and the directions facing each other. At this time, the sectional force of the ring body is expressed by a formula for the two-point concentrated load acting on the ring shown in FIG.

When 0 ≦ θ ≦ φ,

[0063]

(Equation 26)

Are obtained by superimposing. That is, the ring sectional forces M, N, and Q at the study point θ _A (Equation (55) of the embodiment) are given by θ = π / 2−
M when substituting θ _A , φ = π / 2−ψ _A ,
It can be obtained by adding N, Q and M, N, Q when θ = π / 2−θ _A and φ = π / 2 + ψ _B are substituted. In addition, θ _{B of} the study point (Equation (55))
M, N, and Q in Equation (32) are given by θ = π / 2 + θ _B ,
M, N, Q when φ = π / 2−ψ _A is substituted respectively
And M, N, and Q when θ = π / 2 + θ _B and φ = π / 2 + ψ _B are substituted, respectively.

(2) Hollow steel pipe column at the time of reverse symmetric load When the reverse symmetric load shown in FIG. 20 is applied to the hollow steel pipe column, a problem that a two-point concentrated load acts on the pin supporting semicircular arch as shown in FIG. Think as.

In FIG. 21, the bending moment M, the axial force N and the shearing force Q at the angle θ on the arch when the angle between the arch symmetry axis and θ are set to θ (point B in the figure is assumed to be zero). Think. This problem can be solved by superimposing M, N, and Q when a one-point concentrated load acts on a semicircular arch having an effective radius Re shown in FIG.

When a one-point concentrated load acts on the semicircular arch, the bending moment M at the point of the angle θ on the arch,
The axial force N and the shear force Q are given as in equation (33). Where θ is zero at point B and π at point C
/ 2, between the BDs as well, π /
Let it be 2.

When ψ <θ ≦ θ ₀ ,

[0069]

[Equation 27]

However,

[0071]

[Equation 28]

[0072] If there is a horizontal eccentricity, M at the point of the angle θ on the arch of FIG. 21, N, Q, by superposing [psi = [psi _A and [psi = [psi _B with in (33) results, respectively can get.

(3) Hollow steel pipe column under unidirectional load As shown in FIG. 23, when a beam is joined to a ring in only one direction, calculation is performed according to the following procedure.

The load state shown in FIG. 23 is considered as a problem of a ring in which a two-point concentrated load shown in FIG. 24A is acting from one direction. Since the problem of FIG. 24A cannot be solved as it is, it will be considered by decomposing it into the problems of FIGS. FIG. 24 (B) shows the problem of the fixed-end semicircular arch, and FIG. 24 (C) shows that the bending moment is released to the entire ring among the fulcrum reaction forces generated at this time. (The axial reaction force Nc is not released because it is considered to be supported by the steel pipe surface. According to the experimental results, the horizontal reaction force Qc is considered to be supported by the plate bending of the steel pipe surface, It has been confirmed that omitting the release of Qc is closer to the actual behavior.)

Referring to FIG. 24 (B), as shown in FIG. 25, the solution of the problem that a one-point concentrated load acts on the position where the angle formed by the center axis of the fixed arch is + ψ, By superimposing the solution of the problem where a one-point concentrated load acts on the position, M, N,
Q is required. Where θ is zero at point B,
It is π / 2 at point C and −π / 2 at point D. 0 <
When θ < φ,

[0076]

(Equation 29)

However,

[0078]

[Equation 30]

[0079]

(Equation 31)

FIG. 24 (C) finds M, N, and Q acting on the ring, considering the problem of the two-point concentrated moments facing each other. If the angle formed with the central axis in the figure is θ,

[0081]

(Equation 32)

As described above, the problem of FIG.
It is obtained by superimposing the expressions 5) and (38).

When the beam is connected eccentrically in the horizontal direction by the hollow steel pipe column under unidirectional load, the M, N, and Q of the ring are calculated by the following method.

A load state in the case of joining with horizontal eccentricity is considered as shown in FIG. If the same solution as in the case of no eccentricity is used as it is, the reaction force is not balanced in the ring system,
It is very difficult to obtain a solution. Therefore, the two-point concentrated load shown in FIG. 26 is decomposed as shown in FIG. In other words, the angle between the beam direction and the direction connecting the intersection of the center line of the ring and the ring and the center point of the ring with only the eccentric beam flange,

[0085]

[Equation 33]

, And the two-point concentrated load is θc
A direction component P / 2 · cosθc and a direction component P / 2 parallel to
・ Decomposes into sin θc. Here, P / 2 · sin θc is temporarily reserved, and attention is paid only to P / 2 · cos θc to derive M, N, and Q acting on the ring in the same manner as in the case of the above-described non-eccentricity.
Thereafter, P / 2 · sin θc reserved previously is added to N.

(4) CFT In the case of CFT, due to the effect of the filled concrete, a plurality of beams attached to the same column do not affect each other, and the local proof strength of the joint is reduced under any load condition. Experiments and FEM show that the proof strength is not determined by the side flanges but is determined by the minimum value of the local proof strength of each tension side flange.
Has been confirmed by Accordingly, the calculation of the strength of the CFT results in obtaining the local strength of the tensile flange in the column.

The tensile flange joint of the CFT is considered to be an arch having a fulcrum at an angle θo shown in FIG. However, the angle θo is an unknown number and needs to be obtained by the following method.

When a tensile axial force from the beam flange acts on the beam-to-column joint of the CFT, there is a point where the ring body separates from the filled concrete surface (point B in FIG. 29). At this point B, the bending moment is zero and the rotation angle is also zero. Here, assuming that the point of intersection between the central axis of the beam flange and the NT ring is point O, the effective width portion of the NT ring + steel pipe wall does not enter inside the filled concrete portion between the OBs.

FIGS. 30 and 31 illustrate the deformation when a tensile force acts from the beam flange. At the point B, the moment is zero.
The elongation deformation due to the axial force N (changed by θ) acting on the ring becomes Δ, and the deformation due to only the elongation deformation becomes the deformation state shown in FIG. The rotation angle of the point B due to this is defined as θa.

Assuming that the rotation angle of point B due to the bending deformation between AB (see FIG. 31) is θb, θo is a value of θ that satisfies the following equation.

Θa + θb = 0 (40)

If there is no θ that satisfies θa + θb = 0, then θo = θb.

Even when the stiffness of the ring changes in the middle of the circumference, if the stiffness of the ring does not change within θo, it is considered that the same stiffness ring exists over the entire circumference.

(Rotation angle θa of point B by Δ) The axial force of AB is changing. Therefore, it is not constant. In fact, B
At this point, the axial force does not become zero, but it extends and deforms until the ring axial force becomes zero due to the frictional force between the concrete and the ring until point C. Therefore, at the point B, the ring shifts in the direction A. Here, this deviation is ignored. The average value of the axial force between AB is θd = (θ + θo) / 2
At the position of Nd. Nd is represented by the following equation.

[0096]

(Equation 34)

Assuming that the sectional area of the ring including the effective width is A and the Young's modulus is E, the elongation Δ is expressed by the following equation.

[0098]

(Equation 35)

The rotation angle θa of the point B by Δ is given by the following equation from _a geometrical relationship.

[0100]

[Equation 36]

(Rotation angle θ _b due to bending deformation) Bending moment M between AB is a function of θ. And zero rotation angle of the point A by bending deformation, the bending stiffness of the ring I, and the Young's modulus E, the rotation angle theta _b due to bending of the point B is given by the following equation.

[0102]

(37)

(Determination of θ ₀ ) Equation (43) and (44)
Θ ₀ is determined by the equation (40). That is, assuming a certain θ ₀ , a tentative P ₂ is determined by applying the all-plastic condition (21) to the cross-sectional force at the study point of the ring assuming this position as a fulcrum, and N _d , M (α) is determined. From equations (43) and (44), θa and θ
b is obtained, and if equation (40) is satisfied, it is true θ ₀ .

(Proof Strength of CFT Column) If the true θ ₀ is obtained, the axial force N, the shear force Q and the bending moment M can be obtained from the following formula from the formulas.

[0105]

(38)

However, V _A , V _B , and H are based on equation (41).

Consideration point A, ie, θ =
than the value of theta _A, we obtain the true _{P 2.}

When the beams are eccentrically joined in the horizontal direction by the CFT, similarly to the case of the hollow steel tube column under unidirectional load,
M, N, and Q are calculated by decomposing the two-point concentrated load from the beam flange.

The load state in the case of joining with horizontal eccentricity is considered as shown in FIG. If the same solution as in the case of no eccentricity is used as it is, the reaction force is not balanced in the ring system,
It is very difficult to obtain a solution. Therefore, the two-point concentrated load shown in FIG. 26 is decomposed as shown in FIG. That is, the angle between the beam direction and the direction connecting the intersection of the center line of the beam flange and the ring eccentric by e _k and the center point of the ring,

[0110]

[Equation 39]

, And the two-point concentrated load is θc
A direction component P / 2 · cosθc and a direction component P / 2 parallel to
・ Decomposes into sin θc. Here, P / 2 · sin θc is temporarily reserved, and attention is paid only to P / 2 · cos θc to determine values corresponding to ψ and θo at the time of non-eccentricity described above, and M, N, and Q acting on the arch are determined. Lead. After that, P / 2 ・ s which was reserved earlier
inθc is added to N.

(5) Partial ring (under unidirectional load) hollow steel pipe column As shown in FIG. 32, the ring has an open angle 2 on the side where the beam is attached.
If it exists only in the portion of j, that is, if a unidirectional load acts on the partial ring hollow steel pipe, the calculation shall be performed according to the following procedure.

In the case of a partial ring, the effective section of the ring body is a T-shaped section (FIG. 33A, second moment of area: I ₁ ) consisting of a ring and a steel pipe cooperation width in a portion where the ring exists (a portion having an opening angle 2j). ), But it is considered that a portion having no ring changes to a plate-shaped rectangular cross section having only the steel pipe cooperation width (FIG. 33B, second moment of area: I ₂ ). Therefore, as shown in FIG. 34, it is necessary to find the stress distribution (bending moment M, axial force N, shearing force Q) of the arch / ring frame whose sectional performance partially changes from I ₁ to I ₂ .

As in the case of the unidirectionally loaded hollow steel tubular column of the inventor's earlier application, an arch fixed at both ends at an opening angle 2j is assumed, the stress distribution is determined, and the fixed end force is determined. Is obtained by superimposing the stress distribution when releasing from the semicircular ring.

That is, the load state of FIG.
This is considered as a problem of a ring in which a two-point concentrated load shown in FIG. Since the problem of FIG. 35A cannot be solved as it is, it is considered by decomposing it into the problems of FIGS. 35B to 35C. FIG. 35 (B) shows the problem of the fixed end arch, and FIG. 35 (C) shows that the bending moment is released to the entire ring among the fulcrum reaction forces generated at this time. (The axial reaction force Nc is not released because it is considered to be supported by the steel pipe surface. According to the experimental results, the horizontal reaction force Qc is considered to be supported by the plate bending of the steel pipe surface, It has been confirmed that omitting the release of Qc is closer to the actual behavior.)

As for FIG. 35 (B), the solution to the problem that a one-point concentrated load acts at the position where the angle formed with the central axis of the fixed arch having the open angle 2j shown in FIG. 36 is + ψ, and the angle formed with the central axis is −
By superimposing the solution of the problem where a one-point concentrated load acts on the position of ψ, M, M at the point of the angle θ on the arch
N and Q are required. Here, θ is zero at point B, π / 2 at point C, and −π / 2 at point D.

[0117]

(Equation 40)

However,

[0119]

[Equation 41]

Referring to FIG. 35 (C), the problem of the two-point concentrated moment acting on the entire circumference ring is considered as the problem of the one-point concentrated moment acting on the semicircular ring shown in FIG. Think. The stress distribution of the semicircular ring whose stiffness changes is given by the symbol in FIG. 37 as follows. When 0 <θ <ψ,

[0121]

(Equation 42)

Although the solution of FIG. 35C is complicated, as a standard case, as shown in FIG. 38, when the partial ring is exactly half a turn (opening angle 2j = 180 °), the following equation is obtained. Is given in a concise expression, such as

[0123]

[Equation 43]

As described above, the problem shown in FIG.
It is obtained by superposing the expression 9) and the expression (51) (or the expression (52)). When the beam is eccentrically connected in the horizontal direction with a partial ring (unidirectional load) hollow steel pipe column, two points concentrated from the beam flange, as in the unidirectional load hollow steel pipe column of the entire circumference ring Decompose the load to M,
Calculate N and Q. The load state in the case of joining with horizontal eccentricity is considered as shown in FIG. If a solution similar to that used when there is no eccentricity is used as it is, since the reaction force is not balanced in the ring system, it is very difficult to obtain a solution. Therefore, FIG.
The two-point concentrated load shown in FIG. 6 is disassembled as shown in FIG.
That is, the angle between the direction and the beam direction connecting the center point of the intersection and the ring between the center line and the ring beam flange eccentric by e _h,

[0125]

[Equation 44]

, And the two-point concentrated load is θc
A direction component P / 2 · cosθc and a direction component P / 2 parallel to
・ Decomposes into sin θc. Here, P / 2 · sin θc is temporarily reserved, and attention is paid only to P / 2 · cos θc to derive M, N, and Q acting on the ring in the same manner as in the case of the above-described non-eccentricity.
Thereafter, P / 2 · sin θc reserved previously is added to N. Lastly, FIGS. 39 and 40 show a flow of a method of designing a beam-to-column joint portion of a steel pipe column with a ring diaphragm using the above-described method for obtaining a proof strength. In addition, _{P 1} is,
Since P is relatively small with respect to _2, it is also possible to ignore the P ₁ (in the both figures). The column-beam joint design method for the circular steel pipe column with the ring diaphragm according to the embodiment has the following effects because it is configured as described above. Comprehensive, accurate and relatively easy evaluation of beam-column joint strength of circular steel tubular columns with ring diaphragms is now possible. Since it is based on the analytical strength formula, the designer can recognize the flow of force to some extent, and can be applied to special cases. In particular, according to the present invention, it is possible to handle a case where a beam flange is attached with vertical eccentricity and horizontal eccentricity.

[0127]

EXAMPLES (21) from all sections of the molecule is in the form of proportional to P ₂ in formula, it can readily determine the P _2.
However, X 1 _{~X 5} is a coefficient. X ₁ = X ₂ = X ₃ =
When _{X 4 = X 5 = 2,} M when the P ₂ = 1 (unit _{load), N, Q, M θ} , T R , respectively, MA, NA,
If you put a _{QA, M θ A, TR A} , calculation formula of P ₂ is

[0128]

[Equation 45]

Can be written as follows. According to equation (21) or equation (54), it is possible to consider an arbitrary position on the circumference as the study point. I know it is the end. That is, when the horizontal eccentricity is e _h (e _h = 0 when there is no horizontal eccentricity), the points A and B (FIG. 12), which are the corners of the edge of the beam flange, are determined by the study points of the present invention. And The angles θ _A and θ _B formed between the points A and B and the center axis of the flange are given by Expression (55).

[0130]

[Equation 46]

(Example 1) Circular steel pipe column with ring diaphragm φ-318.5 × 10.3, Hs = 16, Ts = 1
6, when the beam flange PL-100x16 is attached in an antisymmetric manner, the yield stress of the steel pipe and the ring is σ _ys = 3.
When 3 (tf / cm ² ) and σ _yt = 3.3 (tf / cm ² ), according to the evaluation formula of the present invention, P ₁ = 10.10 (tf), P ₂
= 18.48 (tf) and P = 28.57 (tf). Therefore, the maximum strength Pu = 35.45 (tf), the short-term permissible yield strength P _A (short) = 24.85 (tf) and long-term tolerance Strength P _A
(Long term) = 16.56 (tf).

When vertical eccentricity _ev = 0.5 (cm) exists, P ₁ = 10.10 (tf), P ₂ = 7.33 (tf), and P = 17.43 (tf). Therefore, the maximum proof stress Pu =
21.62 (tf), short-term allowable strength P _A (short-term) = 15.
15 (tf) and long-term allowable strength P _A (long-term) = 10.1
0 (tf).

When there is a horizontal eccentricity e _h = 5.0 (cm), P ₁ = 10.10 (tf) and P ₂ = 16.68 (tf)
And P = 26.78 (tf). Therefore, the maximum proof stress Pu
= 33.22 (tf), short-term allowable strength P _A (short-term) = 2
3.28 (tf) and long-term allowable strength P _A (long-term) = 1
5.52 (tf).

(Embodiment 2) In the present evaluation equation, the coefficients X ₁ to X ₁
FIG. 41 shows a comparison between the calculation result when X ₅ is set to X ₁ = X ₂ = X ₃ = X ₄ = X ₅ = 2 and the experimental result or the FEM analysis result.

The number, position, shape, and the like of the above-mentioned constituent members are not limited to the above-described embodiment, but can be set to a number, position, shape, and the like suitable for carrying out the present invention. For example, a radius of the flange of the beam may be provided. In such a case, it is preferable to perform the test at the edge of R.

In the respective drawings, the same components are denoted by the same reference numerals.

[0137]

Since the present invention is configured as described above, the following effects can be obtained. Since the calculation is made using the analytical strength formula instead of the empirical formula, it is possible to present a simple and general-purpose method for obtaining the strength of the steel pipe column while maintaining a constant accuracy of the beam-column joint strength of the steel pipe column. .

[Brief description of the drawings]

FIG. 1 is a partially broken perspective view of a steel pipe column with a ring diaphragm to which the present invention is applied.

FIG. 2 (A) is a partially cutaway perspective view of a thickened steel pipe column to which the present invention is applied, and FIG. 2 (B) is a partially cutaway perspective view of a special steel pipe column with a ring diaphragm.

FIG. 3 is a detailed sectional view of a fitting portion of the steel pipe column shown in FIG. 2;

FIG. 4 is a diagram showing a state of a long-term load (symmetric load) according to a conventional technique.

FIG. 5 is a diagram showing an earthquake load (reverse symmetric load) state according to the related art.

FIG. 6 is a diagram showing decomposition of a beam flange axial force into two components according to the embodiment of the present invention.

7 is a diagram showing details of disassembly of the beam flange axial force shown in FIG. 6 into two components.

FIG. 8 is a diagram showing a definition of an effective circumference S according to the embodiment of the present invention.

FIG. 9 is a diagram showing a definition of an effective width α of an NT ring according to the embodiment of the present invention.

FIG. 10 is a diagram showing an operation position の of a two-point concentrated load according to the embodiment of the present invention.

FIG. 11 is a diagram showing applied positions ψA and ψB of a two-point concentrated load when there is horizontal eccentricity according to the embodiment of the present invention.

FIG. 12 is a diagram showing a study point of a ring body according to the embodiment of the present invention.

FIG. 13 is a partial longitudinal sectional view of a ring portion showing vertical eccentricity according to the embodiment of the present invention.

FIG. 14 is a diagram illustrating a definition of ψ and an added moment due to vertical eccentricity according to the embodiment of the present invention.

FIG. 15 is a diagram showing a semicircular arch to which a two-point concentrated load acts according to the embodiment of the present invention.

FIG. 16 is a diagram showing a semicircular arch to which a one-point concentrated load acts according to the embodiment of the present invention.

FIG. 17 is a diagram showing a case where a target load acts according to the embodiment of the present invention.

FIG. 18 is a diagram showing a case where a target load acts according to the embodiment of the present invention.

FIG. 19 is a diagram showing opposed two-point concentrated loads acting on the ring according to the embodiment of the present invention.

FIG. 20 is a diagram showing a case where a reverse symmetric load acts according to the embodiment of the present invention.

FIG. 21 is a view showing a semicircular arch to which a two-point concentrated load acts according to the embodiment of the present invention.

FIG. 22 is a diagram showing a semicircular arch to which a one-point concentrated load acts according to the embodiment of the present invention.

FIG. 23 is a diagram showing a case where a one-way load acts according to the embodiment of the present invention.

FIGS. 24A to 24C are diagrams showing a solution when a one-way load is applied, according to the embodiment of the present invention.

FIG. 25 is a view showing a fixed-end semicircular arch to which a one-point concentrated load acts according to the embodiment of the present invention.

FIG. 26 is a diagram showing a horizontal eccentric unidirectional load according to the embodiment of the present invention.

FIG. 27 is a diagram showing decomposition of a two-point concentrated load according to the embodiment of the present invention.

FIG. 28 is a diagram showing a CFT arch model according to the embodiment of the present invention.

FIG. 29 is a diagram showing a deformation of the CFT ring body according to the embodiment of the present invention.

FIG. 30 is a diagram showing a fulcrum rotation angle θa due to elongation of the CFT ring body according to the embodiment of the present invention.

FIG. 31 is a diagram showing a fulcrum rotation angle θb due to elongation of the CFT ring body according to the embodiment of the present invention.

FIG. 32 is a view showing a circular steel pipe column with a ring tie diaphragm in a portion that receives a unidirectional load according to the embodiment of the present invention.

33A is a diagram showing an effective cross section of a portion where a ring exists according to the embodiment of the present invention, and FIG. 33B is a diagram showing an effective cross section of a portion where no ring exists. FIG.

FIG. 34 is a diagram illustrating an arch / ring skeleton with varying cross-sectional performance according to an embodiment of the present invention.

FIGS. 35A to 35C are diagrams showing a solution when unidirectional weight is applied to the partial ring according to the embodiment of the present invention.

FIG. 36 is a diagram showing a fixed-end arch on which a one-point concentration direction load acts according to the embodiment of the present invention.

FIG. 37 is a diagram showing a semicircular ring whose rigidity changes at a bending moment action point according to the embodiment of the present invention.

FIG. 38 is a diagram showing a case where the opening angle is 180 ° according to the embodiment of the present invention.

FIG. 39 is a flowchart showing a flow of a method of designing a beam-to-column joint of a steel pipe column with a ring diaphragm according to an embodiment of the present invention.

40 is a flowchart showing a continuation of the flow shown in FIG. 39.

FIG. 41 is a diagram showing a comparison between a calculation result according to the present embodiment and an experimental result or FEM.

[Explanation of symbols]

 α: Effective width S: Effective circumference ψ: Load acting position D: Diameter of steel pipe tc: Plate thickness of steel pipe tp: Plate thickness of connection thickening portion lp: Extra length of connection thickening portion Hs: Ring length Out Ts: Ring thickness Bf: Beam flange width tf: Beam flange thickness σyt: Yield strength of steel pipe σys: Yield strength of ring

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Ishimura 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Nobuyuki Nakamura 1-2-1, Marunouchi, Chiyoda-ku, Tokyo, Japan (72) Inventor Toshiaki Miyao 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Japan 1-2.Inventor Junichi Takagi 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Inside the corporation

Claims (23)

[Claims] When a beam flange is attached to a hollow circular steel tubular column with a ring diaphragm or a concrete-filled circular steel tubular column with a ring diaphragm with a vertical eccentricity with respect to the ring diaphragm, the strength of the column-beam joint portion of the steel tubular column is determined. A flow component (P ₁ ) of the force transmitted by bending deformation of the steel pipe wall near the beam, and a flow component of the force transmitted in the circumferential direction by bending of the ring and the steel pipe sheet near the ring. (P ₂ ) A method of determining the proof stress of a beam-column joint in a steel pipe column from the sum with (P ₂ ) 2. When a beam flange is attached to a hollow circular steel tubular column with a ring diaphragm or a concrete-filled circular steel tubular column with a ring diaphragm with a vertical eccentricity with respect to the ring diaphragm, the strength of the column-beam joint portion of the steel tubular column is determined. A flow component (P ₁ ) of the force transmitted by bending deformation of the steel pipe wall near the beam, and a flow component of the force transmitted in the circumferential direction by bending of the ring and the steel pipe sheet near the ring. (P ₂ ) and a method of determining the proof stress of the beam-column joint of the steel pipe column from the component (P ₂ ). 3. A method for determining the strength of a column-beam joint of a steel pipe column when a beam flange subjected to a symmetric load is mounted on a hollow circular steel pipe column with a ring diaphragm with horizontal eccentricity relative to the ring diaphragm. The flow component of the force transmitted by bending deformation of the steel pipe wall near the beam attachment (P ₁ ), and the flow component of the force transmitted in the circumferential direction by the bending of the ring and the steel pipe plate near the ring (P ₂ ) A method for determining the strength of a beam-column joint in a steel pipe column from the sum of 4. A method for determining the strength of a column-beam joint of a steel pipe column when a beam flange subjected to a symmetric load is attached to a hollow circular steel pipe column with a ring diaphragm with horizontal eccentricity with respect to the ring diaphragm. The flow component of the force transmitted by bending deformation of the steel pipe wall near the beam attachment (P ₁ ), and the flow component of the force transmitted in the circumferential direction by the bending of the ring and the steel pipe plate near the ring (P ₂ ) And deriving the proof stress of the beam-column joint of the steel pipe column from the component (P ₂ ). 5. A method for determining the strength of a column-beam joint of a steel tubular column when a beam flange subjected to an antisymmetric load is mounted on a hollow circular steel tubular column with a ring diaphragm with horizontal eccentricity with respect to the ring diaphragm. The flow component (P ₁ ) of the force transmitted by bending deformation of the steel pipe wall near the beam and the flow component (P ₂ ) of the force transmitted in the circumferential direction due to the bending of the ring and the steel pipe plate near the ring And the strength of the beam-to-column joints in steel pipe columns. 6. A method for determining the strength of a column-beam joint portion of a steel pipe column when a beam flange subjected to an antisymmetric load is attached to a hollow circular steel pipe column with a ring diaphragm with horizontal eccentricity relative to the ring diaphragm. The flow component (P ₁ ) of the force transmitted by bending deformation of the steel pipe wall near the beam and the flow component (P ₂ ) of the force transmitted in the circumferential direction due to the bending of the ring and the steel pipe plate near the ring And deriving the strength of the beam-column joint portion of the steel pipe column from the component (P ₂ ). 7. A method for determining the strength of a column-beam joint portion of a steel pipe column when a beam flange subjected to a unidirectional load is attached to a hollow circular steel pipe column with a ring diaphragm with horizontal eccentricity relative to the ring diaphragm. The flow component (P ₁ ) of the force transmitted by bending deformation of the steel pipe wall near the beam and the flow component (P ₂ ) of the force transmitted in the circumferential direction due to the bending of the ring and the steel pipe plate near the ring A method for determining the strength of a beam-column joint in a steel pipe column from the sum of 8. A method for determining the strength of a column-beam joint of a steel tubular column when a beam flange receiving a unidirectional load is attached to a hollow circular steel tubular column with a ring diaphragm with horizontal eccentricity relative to the ring diaphragm. The flow component (P ₁ ) of the force transmitted by bending deformation of the steel pipe wall near the beam and the flow component (P ₂ ) of the force transmitted in the circumferential direction due to the bending of the ring and the steel pipe plate near the ring And deriving the strength of the beam-column joint portion of the steel pipe column from the component (P ₂ ). 9. A method for determining the strength of a beam-column joint of a steel pipe column when the beam flange is attached to a concrete-filled circular steel pipe column with a ring diaphragm with a horizontal eccentricity with respect to the ring diaphragm. The flow component (P ₁ ) of the force transmitted by bending deformation of the steel pipe wall near the mounting and the flow component (P ₂ ) of the force transmitted in the circumferential direction due to the bending of the ring and the steel pipe plate near the ring To determine the strength of column-beam joints in steel pipe columns. 10. A method for determining the strength of a beam-column joint of a steel pipe column when the beam flange is attached to a concrete-filled circular steel pipe column with a ring diaphragm with a horizontal eccentricity with respect to the ring diaphragm. The wall surface of the steel pipe in the vicinity of the attachment is decomposed into a flow component (P ₁ ) of the force transmitted by bending deformation and a flow component (P ₂ ) of the force transmitted in the circumferential direction due to the bending of the ring and the steel tube plate near the ring. A method for determining the proof stress of the beam-column joint of the steel pipe column from the component (P ₂ ). 11. A method for determining the strength of a beam-column joint of a steel pipe column when a beam flange subjected to a unidirectional load is attached to a hollow circular steel pipe column with a partial ring diaphragm with horizontal eccentricity relative to the ring diaphragm. there are, the force of the flow component which is deformed bending steel wall in the vicinity of the beams attach transmission (P _1), the force of the flow component which is transmitted by the bending of a steel pipe plate ring and the ring near the peripheral direction (P ₂ ), The strength of the beam-column joint of the steel pipe column is determined. 12. A method for determining the strength of a beam-column joint in a steel tubular column when a beam flange receiving a unidirectional load is attached to a hollow circular steel tubular column with a partial ring diaphragm with horizontal eccentricity relative to the ring diaphragm. there are, the force of the flow component which is deformed bending steel wall in the vicinity of the beams attach transmission (P _1), the force of the flow component which is transmitted by the bending of a steel pipe plate ring and the ring near the peripheral direction (P ₂ ), And from the component (P ₂ ), the strength of the beam-column joint of the steel pipe column is determined. 13. The column-beam joint portion of a steel pipe column according to claim 3, wherein the beam flange is attached to the ring diaphragm with a vertical eccentricity. How to ask. 14. The method according to claim 1, wherein said P ₁ is obtained by the following equation.
14. The method according to 11 or 13, wherein the strength of the beam-column joint of the steel pipe column is obtained. (Equation 5) 15. The method according to claim 14, wherein said S is determined by the following equation. (Equation 9) 16. The method according to claim 1, wherein said P ₂ is determined by the following equation. Here, X ₁ , X ₂ , X ₃ , X ₄ , and X ₅ are coefficients. (Equation 15) , , And 17. The method according to claim 1, wherein the effective width α of the steel pipe portion is obtained by the following equation.
7. The method for determining the strength of a beam-column joint in a steel pipe column according to 6. (Equation 10) 18. The method according to claim 1, wherein the effective width α of the steel pipe portion is obtained by the following equation.
7. The method for determining the proof strength of a beam-column joint of a steel pipe column according to 6. [Equation 11] 19. The column-beam joint part of the steel pipe column according to claim 1, wherein the steel pipe column is a steel pipe column having a thickened connection portion with the beam. How to find the proof stress of 20. A method for designing a beam-to-column joint in a steel pipe column, using the method for obtaining a proof stress according to claim 1. Description: 21. A recording medium on which is recorded a program capable of executing the method according to any one of claims 1 to 19 for determining the strength of a beam-column joint of a steel pipe column. 22. A recording medium on which is recorded a program capable of executing the method for designing a beam-column joint of a steel pipe column according to claim 20. 23. A structure constructed by the method for designing a beam-column joint of a steel pipe column according to claim 20.