JP2000240152A - A method for determining the strength of beam-column joints in steel tubular columns - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple and versatile method for obtaining the proof strength of a beam-column joint in a steel pipe column while maintaining a constant accuracy of the strength of the beam-column joint of a steel pipe column. In this regard, a design method of a beam-column joint in a steel pipe column using such a method for obtaining the strength is presented. SOLUTION: The flow of beam flange axial force to a column is shown in FIG.
As shown in (a) and FIG. 6 (b), it is assumed that the two components are decomposed into two components. Evaluate as proof stress. As shown in FIG. 7, the flow of component 1 (hereinafter referred to as “front shearing force”) P1 is a flow of force transmitted mainly in the axial direction of the steel pipe by bending and deforming the wall surface of the steel pipe near where the beam is attached. The flow of component 2 (hereinafter referred to as "ring strength") P2 is the flow of force transmitted in the ring circumferential direction due to bending of the ring and the steel tube sheet near 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. 2 (a) and FIG. 2 (b), which is a special case of a hollow steel tube column (hereinafter, referred to as "integral ring type") in which a portion to be joined with the beam shown in FIG. The hollow circular steel pipe column not thickened as shown in
The present invention relates to a method for determining the local strength of a joint when a beam flange is attached.

[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. 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 first aspect of the present invention is that a flow component (P ₁ ) of a force transmitted by bending deformation of a wall surface of a steel pipe in the vicinity of a position where a beam is attached, and that the force is transmitted in a circumferential direction by bending of a ring and a steel pipe plate in the vicinity of the ring. There is a method for determining the proof stress of a beam-column joint in a steel pipe column from the sum with the force flow component (P ₂ ). The gist of the invention according to claim 2 is that the flow component (P ₁ ) of the force transmitted by bending deformation of the steel pipe wall surface near the beam and the circumferential direction is transmitted by bending of the ring and the steel pipe plate near the ring. It decomposes into a force flow component (P ₂ ) and uses the component (P ₂ ) to determine the proof stress of the beam-column joint of the steel pipe column. The gist of the invention according to claim 3 resides in the method for determining the strength of a beam-column joint in a steel pipe column according to claim ₁ , wherein the P ₁ is determined by the following formula.

(Equation 5) The gist of the invention according to claim 4 resides in the method according to claim 3, wherein the S is determined by the following equation:

(Equation 9) Summary of the Invention in claim 5, wherein P ₂ is claims 1 to 4, characterized in that determined by the formula listed below
The method according to any one of the above, wherein the strength of the beam-to-column joint of the steel pipe column is obtained. Here, X ₁ , X ₂ , X ₃ ,
X ₄ and X ₅ are coefficients.

[Equation 14] ,

(Equation 15) ,as well as

(Equation 16) The gist of the invention according to claim 6 is that the effective width α of the steel pipe portion is obtained by the following formula, and the method for obtaining the proof strength of a beam-column joint portion in a steel pipe column is described. Exists.

(Equation 10) The gist of the invention according to claim 7 is that the effective width α of the steel pipe portion is obtained by the following formula, and the proof strength of the column-beam joint portion of the steel pipe column according to claim 5 is obtained. Be in the way.

[Equation 11] The gist of the invention according to claim 8 is that the steel pipe column is a steel pipe column with a ring diaphragm, and finds the proof strength of the column-beam joint portion in the steel pipe column according to any one of claims 1 to 7. Be in the way. The gist of the invention according to claim 9 is that, in the steel pipe column, the steel pipe 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 The gist of the invention described in claim 10 resides in a method of designing a beam-column joint portion in a steel pipe column using the method for obtaining proof stress according to claims 1 to 9. The gist of the invention described in claim 11 resides in a recording medium storing 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 9.
The gist of the invention according to claim 12 is as set forth in claim 10,
The present invention resides in a recording medium on which a program capable of executing a method of designing a beam-column joint in a steel pipe column is recorded. The gist of the invention described in claim 13 resides in a structure constructed by the method for designing a beam-column joint of a steel pipe column according to claim 10.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. Assuming that the flow of the axial force of the beam flange to the column is decomposed into two flow components as shown in FIGS. 6 (a) and 6 (b), each component is subjected to analytical strength 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.
A force flow predominantly beam) P ₁ as "front shear force" is transmitted to the steel pipe wall bending deformation axial direction of the steel pipe in the vicinity that have attached, the flow of the components 2 (hereinafter, "Ring Strength"
) P ₂ that 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 shearing force P ₁ is obtained from the cylindrical shell theory. Calculation formula of 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, the flange axial force is regarded as a two-point concentrated load acting on the acting position ψ as shown in FIG.

The effective width α was set as shown in equation (10) or (11) based on the results of experiments and FEM.

(Equation 10)

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

[0027]

[Equation 11]

The effective radius Re is

[0029]

(Equation 12)

Where g is

[0031]

(Equation 13)

When there is no horizontal eccentricity due to the inverse symmetric load, when the axial force of the beam flange is regarded as a two-point concentrated load, the acting position ψ is set as shown in equation (18) from the results of experiments and FEM.

[0033]

[Equation 14]

[0034] _However, when the _{B f -H s ≦ H s /} 2 is,

[0035]

(Equation 15)

Ring strength P₂Is the total plastic strength of the ring
M_P, N_P, Q_P, Mθ_PAnd T _RPFor
Moment M, axial force N, shear
Force Q, out-of-plane bending moment Mθ and torque T_RPlastic
Conditional expression:

[0037]

(Equation 16)

Calculate by applying

The total plastic strength M _P , N _P , Q _P ,
Mθ _P and T _RP are calculated according to the following formulas:

[0040]

[Equation 17]

[0041]

(Equation 18)

[0042]

[Equation 19]

Is determined assuming that only the ring portion is effective (ignoring the steel pipe portion) and using equations (25) and (26) and (27), respectively.

[0044]

(Equation 20)

[0045]

(Equation 21)

In the ring integrated type, the effective width α is (1
In addition to setting by equation (1), equations (21) to (2)
_H s = ₀ in _{7), T} s = _{t f} and _t c = _{t p}
Is obtained by substituting

The bending moment M necessary ring body in the calculation of P _2, the axial force N, shear force Q, plane bending moment Mθ
And the torque T _R (hereinafter referred to as “cross-section force of the ring body”) have different calculation methods depending on the load state, the presence or absence of concrete filling, the presence or absence of eccentricity, the shape of the ring, and the like.
It is classified into the following cases.

(1) Hollow steel tube column under symmetric load (2) Hollow steel tube column under anti-symmetric load (3) Hollow steel tube column under unidirectional load (4) CFT

Among them, the present invention relates to (2) a case where a vertical eccentricity and a horizontal eccentricity do not exist in a hollow steel tubular column under an antisymmetric load.

Of the sectional forces of the ring body, the surface shown in FIG.
Outer bending moment Mθ and torque T _RIs the
(1) to (4), with vertical eccentricity
Because

[0051]

(Equation 22)

[0052]

(Equation 23)

In the present invention which deals with the case where there is no vertical eccentricity,
Is e_v= 0, Mθ = 0, T _R= 0.

On the other hand, the bending moment M, the axial force N, and the shear force Q among the sectional forces of the ring body are derived from the arch / ring framework theory by appropriately assuming boundary conditions corresponding to each case. Hereinafter, the bending moment M when the load P ₂ acts on the beam flange, the axial force N, the method for calculating shear force Q, according to the present invention (2) described with respect to anti-symmetric loads when hollow steel column.

(2) Hollow steel pipe column at the time of inverse symmetric load When the antisymmetric load shown in FIG. 13 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. 14, the bending moment M, the axial force N, and the shear force Q at the angle θ on the arch when the angle between the arch and the axis of symmetry is θ (point B in the figure is zero) are set. 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 equations (30) to (32). Where θ is zero at point B,
Π / 2 at point C and π / 2 at point D with the point B as the starting point between BDs.

[0058]

(Equation 24)

However,

[0060]

(Equation 25)

Finally, FIGS. 16 and 17 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, since the relatively small with respect to _{P 2,} can also be ignored _{P 1} (in the both figures).

The method for obtaining the proof stress of the beam-column joint portion of the steel pipe column with the ring diaphragm according to the present embodiment is that the evaluation of the proof stress of the beam-column joint portion of the steel pipe column with the ring diaphragm is performed comprehensively, accurately and relatively easily. It is now possible.

Further, since it is based not on the empirical formula but on the analytical stress formula, the designer can recognize the flow of the force to some extent, and can be applied to special cases.

[0064] (Example 1) (20) Molecular terms, all coefficients _X 1 because is in the form which is proportional to _{P 2} ~ In Equation
The X _5, when the _{X 1 = X 2 = X 3} = X 4 = X 5 = 2, can easily seek _{P 2. That,} M when the _P 2 = 1 (unit load), N, Q, Mθ, respectively _{T R, M A, N A} , Q A, Mθ A, if put as _{T RA, P 2}
The calculation formula of

[0065]

(Equation 26)

Can be written as follows.

According to the equation (20), it is possible to set an arbitrary position on the circumference as a study point.
From the M results, it is known that the most critical study point is the end of the corner processed portion with the flange edge. That is, the points A and B (FIG. 11), which are the entry corners of the edge of the beam flange, are considered as the study points of the present invention. Point A and B
The angles θ _A and θ _B formed between the point and the flange center axis are given by the equations (35) and (36).

[0068]

[Equation 27]

Here, r is the radius of the corner formed at the welded portion of the beam flange (usually r = 1 cm).

Circular steel pipe column φ-31 with ring diaphragm
8.5x10.3, Hs = 16, Ts = 16, beam franc
When the PL-100x16 is attached in antisymmetric,
The yield stress of the_ys= 3.3 (tf / c
m²), Σ_yt= 3.3 (tf / cm²)
According to Ming's evaluation formula, P₁= 10.10 (tf), P ₂
= 24.53 (tf), and P = 34.63 (t
f). Therefore, the maximum proof stress P _U= 42.96 (tf), short
Initial allowable strength P_A(Short term) = 30.11 (tf) and long
Initial allowable strength P_A(Long term) = 20.08 (tf).

[0071] evaluation by FEM under the same conditions, at the time of 1/3 rigidity in compression-side flange strength _P K0 _/ 3 = 28.20 (t
f), 1/10 rigidity when the strength _P K0 _/ 10 = 35.30
(Tf).

Further, a push-pull experiment under the same conditions (5-1 specimen)
The experimental result of the test shows that the compression flange has a proof stress of 1/3 rigidity P
_K0/₃= 34.90 (tf), strength P at 1/10 rigidity
_K0/ ₁₀= 47.00 (tf) maximum proof stress P_MAX= 5
2.10 (tf).

Therefore, it can be said that the evaluation formula of the present invention gives a safe evaluation with high accuracy.

(Embodiment 2) In the present evaluation equation, the coefficients X ₁ to X ₁
FIG. 18 shows a comparison between a calculation result when X ₅ is set to X ₁ = X ₂ = X ₃ = X ₄ = X ₅ = 2 and an experimental result or 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, the radius of the flange of the beam can 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.

[0077]

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 certain 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.

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 a study point of a ring body according to the embodiment of the present invention.

[12] according to an embodiment of the present invention, showing a plane bending moment Mθ and torque T _R.

FIG. 13 is a diagram showing a case where an antisymmetric load acts according to the embodiment of the present invention.

FIG. 14 is a diagram showing a semicircular arch to which a two-point concentrated load acts according to the embodiment of the present invention.

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

FIG. 16 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.

FIG. 17 is a flowchart showing a continuation of the flow shown in FIG. 16;

FIG. 18 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: Pre-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 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Inside the corporation

Claims (13)

[Claims] 1. A flow component (P ₁ ) of a force transmitted by bending deformation of a steel pipe wall near a beam and a flow component (P ₁ ) of a force transmitted in a circumferential direction by bending of a ring and a steel pipe plate near a ring. A method of determining the proof stress of a column-beam joint part in a steel pipe column from the sum of P ₂ ). 2. A flow component (P ₁ ) of the force transmitted by bending deformation of the steel pipe wall near the beam and a flow component (P ₁ ) of the force transmitted in the circumferential direction by bending of the ring and the steel pipe sheet near the ring. P ₂ ), and from the component (P ₂ ), the strength of the beam-column joint of the steel pipe column is determined. 3. The method according to claim 1, wherein said P ₁ is obtained by the following equation. (Equation 5) 4. The method according to claim 3, wherein said S is determined by the following equation. (Equation 9) 5. The method according to claim 1, wherein said P ₂ is obtained by the following equation. Here, X ₁ , X ₂ , X ₃ , X ₄ , and X ₅ are coefficients. [Equation 14] , , And 6. The method according to claim 5, wherein the effective width α of the steel pipe portion is obtained by the following equation. (Equation 10) 7. The method according to claim 5, wherein the effective width α of the steel pipe portion is obtained by the following equation. [Equation 11] 8. The method according to claim 1, wherein the steel pipe column is a steel pipe column with a ring diaphragm. 9. The steel pipe column according to claim 1, wherein said steel tube column is a steel tube column having a thickened connection portion with said beam.
The method for determining the proof strength of a beam-column joint of a steel pipe column according to any one of the above. 10. A method of designing a beam-column joint in a steel pipe column using the method for obtaining proof stress according to claim 1. 11. The method according to claim 1, wherein
A recording medium on which is recorded a program capable of executing a method for determining the strength of a beam-column joint in a steel pipe column. 12. A recording medium on which is recorded a program capable of executing the method of designing a beam-column joint of a steel pipe column according to claim 10. 13. A structure constructed by the method for designing a beam-column joint of a steel pipe column according to claim 10.