Connection structure between CFT column and RC column

Abstract

To provide a connection structure between a CFT column and a RC column allowing shear deformation at a connection steel pipe part to be calculated from shear strain of the connection steel pipe part of the CFT column measured at an experiment.SOLUTION: Shear deformation δs of a connection steel pipe part where a connection steel pipe part is formed on an upper end part of a CFT column such that a steel pipe projects above, a main bar of a RC column is inserted inside of the connection steel pipe as well as concrete is installed inside of the connection steel, a reinforcement part projecting inward from an inner surface is arranged on an upper end of the connection steel pipe, and an anchor plate is arranged on a lower end part of the main bar, is calculated as showed by formula (3) by integrating γ at Δz in a HS direction of CFT column steel pipe height after substituting β acquired by formula (1) into formula (2) representing shear deformation angle γ by means of the formula (2), as shear strain measured at x=-x0,0,x0 upon an experiment is represented as given by the formula (1) as εγ1,εγ0,εγ2.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a joint structure between a CFT column and an RC column. [Background technology]

[0002] In component testing, it is necessary to evaluate the deformation components (bending deformation, shear deformation) of each part when a load acts on the component and the entire component deforms.Shear deformation is generally calculated using the measured values ​​of a high-sensitivity displacement meter (hereinafter referred to as displacement meter) installed on the component (the test specimen used in the experiment).

[0003] Meanwhile, the inventors of the present invention have proposed a joint structure of a CFT column and an RC column (hereinafter, sometimes referred to as a CFT-RC column), as shown in Patent Document 1 below. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7228398 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when attempting to measure shear deformation, there may be physical restrictions on where to install the displacement meters due to the size of the test specimen, displacement meters installed for other purposes, or the space available to install the displacement meters, making it impossible to measure shear deformation. This is a problem that also arises when measuring shear deformation in the joint structure between a CFT column and an RC column shown in Patent Document 1.

[0006] In consideration of the above circumstances, the present invention proposes a joint structure between a CFT column and an RC column in which the shear deformation in the joint steel pipe part is calculated from the shear strain in the joint steel pipe part of the CFT column measured during experiments. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention employs the following means. That is, the joint structure between a CFT column and an RC column according to the present invention is a joint structure between a CFT column and an RC column that joins a CFT column and an RC column arranged above the CFT column, in which a joint steel pipe formed to extend upward is provided at the upper end of the CFT column, the main reinforcement of the RC column is inserted inside the joint steel pipe, and the inside of the joint steel pipe is filled with concrete, a stiffening part that protrudes inward from the inner surface is provided at the upper end of the joint steel pipe, and an anchor plate is provided at the lower end of the main reinforcement, and the shear deformation of the joint steel pipe is calculated by dividing the shear strain at x = -x0, 0, x0 measured during the experiment by ε γ1 ,ε γ0 ,ε γ2 The shear deformation angle γ is expressed as in equation (A), and β is calculated from equation (A). This is substituted into equation (B) to calculate γ. Then, γ at Δz is calculated by the height H of the joining steel pipe. S By integrating in the direction, the shear deformation δ s Calculate.

[0008]

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[0009] In the joint structure between a CFT column and an RC column configured in this way, the shear deformation in the joint steel pipe part can be calculated from the shear strain in the steel pipe part of the CFT column measured during the experiment. [Effects of the Invention]

[0010] According to the joint structure between a CFT column and an RC column of the present invention, the shear deformation in the joint steel pipe part can be calculated from the shear strain in the joint steel pipe part of the CFT column measured during the experiment. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing a joint structure between a CFT column and an RC column according to one embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 10 is a diagram showing the shear force acting on the joint structure between a CFT column and an RC column. [Figure 6] FIG. 2 is a cross-sectional view taken along line VI-VI in FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 10 is a diagram showing the distribution of shear stress intensity occurring on the shear force bearing surface of the steel pipe part of a CFT column. [Figure 9] FIG. 1 is an elevation view of the test specimen. [Figure 10] 10 is a cross-sectional view taken along line XX in FIG. 9. [Figure 11] FIG. 10 is a cross-sectional view taken along line XI-XI in FIG. 9. [Figure 12] FIG. 10 is a diagram showing the calculation results of the shear deformation angle γ. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, a joint structure between a CFT column and an RC column according to an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a diagram showing a joint structure between a CFT column and an RC column according to one embodiment of the present invention. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 1. Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 1. The joint structure 20 between a CFT column and an RC column of this embodiment shown in Figures 1 to 4 is applied to, for example, the framework of a warehouse in a multi-story logistics facility. The warehouse is configured, for example, with lower floors exceeding 10 meters in height and equipped with a multi-story and complex material handling rack. Furthermore, the lower floor 1a of the higher floors is configured as a CFT structure with CFT columns 2, and the upper floor 1b is configured as an RCS structure with a hybrid framework combining RC columns 3 and steel beams 4.

[0013] The joint structure 20 between CFT columns and RC columns is not limited to application to multi-story logistics facilities; it may also be adopted in facilities where the lower floors (lower floors 1a) of the CFT structure are used as offices or commercial facilities, and the upper floors (upper floors 1b) of the RCS structure or RC structure are used as a complex facility with residences and hotels; there is no need to limit the scope of application as long as the lower floors 1a are equipped with CFT columns 2 and the upper floors 1b are equipped with RC columns 3.

[0014] In the joint structure 20 between a CFT column and an RC column of this embodiment, the steel pipe 5 of the CFT column 2 in the lower layer 1a extends upward from the top 2a of the CFT column 2 to approximately the root wrapping level (approximately 1.5 m). The main reinforcement 7 of the RC column 3 in the upper layer 1b is inserted into the inside of the connecting steel pipe (root wrapping steel pipe) 6, which is the extending part of the steel pipe 5, and concrete 8 is poured and filled, and the main reinforcement 7 is fixed to the concrete 8.

[0015] As shown in Figure 4, the joined steel pipe 6 has a square cylindrical shape. On the top 6a (see Figure 1) side of the joined steel pipe 6, an annular rib plate is provided as a stiffening part 9 that protrudes inward from the inner surface of the upper end of the joined steel pipe 6 and extends circumferentially. The stiffening parts 9 are provided on all four sides of the joined steel pipe 6. The stiffening parts 9 stiffen the joined steel pipe 6 to suppress out-of-plane deformation.

[0016] As shown in Figure 1, an anchor plate 10 is attached to the lower end 7d of the main reinforcement 7 of the RC column 3 at the portion inserted into the connecting steel pipe 6. The anchor plate 10 integrates the main reinforcement 7 with the concrete 8 inside the connecting steel pipe 6, preventing the main reinforcement 7 from slipping out of the concrete 8 inside the connecting steel pipe 6 as deformation gradually increases.

[0017] Next, the methods for calculating shear deformation from the shear strain in the CFT column steel pipe (joint steel pipe 6) are listed below.

[0018] The shear forces acting on the CFT-RC column are shown in Figures 5 to 7. It is assumed that the shear stress intensity is distributed on the shear force bearing surface of the CFT column steel pipe part (connected steel pipe 6) as shown in Figure 8. The shear force bearing surface is indicated by hatching.

[0019] The shear stress τ is expressed by equation (1).

[0020]

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[0021] The strain energy of the infinitesimal space Δz is ΔP E Then, ΔP E is expressed by equation (2).

[0022]

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[0023] Shear force Q at Z position Z is expressed by equation (3).

[0024]

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[0025] Substituting equation (1) into equation (4), Q Z is expressed by equation (4).

[0026]

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[0027] From equation (4), τ max is expressed as equation (5).

[0028]

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[0029] From the relationship τ=Gγ, equation (2) can be expressed as equation (6).

[0030]

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[0031] Substituting equation (1) into equation (6), ΔP E is expressed by equation (7).

[0032]

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[0033] The shear deformation at Δz is Δδ s Then, according to Castigliano's theorem, we obtain equation (8).

[0034]

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[0035] Using the relationship τ=Gγ, equation (1) can be expressed in terms of γ as equation (9).

[0036]

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[0037] The shear strain at x=-x0, 0, x0 obtained from the experiment is ε γ1 ,ε γ0 ,ε γ2 Then, equation (10) is obtained.

[0038]

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[0039] On the other hand, the shear deformation angle γ is expressed by equation (11) based on equation (9).

[0040]

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[0041] Shear deformation δ sβ is calculated from equation (10), and this is substituted into equation (11) to calculate γ. Then, γ at Δz is calculated by multiplying the CFT column steel pipe (connected steel pipe) height H S By integrating in the direction, it is calculated as shown in equation (12).

[0042]

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[0043] Next, using the CFT-RC column specimens shown in Table 1 below as examples, the shear deformation δ s The test specimens are shown in Figures 9 to 11.

[0044] [Table 1]

[0045] The test results are shown in Figure 12. The member angle (%) R is calculated using the following formula: R=δ H / force point height (=1750mm)×100(%), δ H : Horizontal displacement of the load point (mm) (1) γ at each z position when R=+0.5% is as follows: z=55mm, γ=0.000393634 z=270mm, γ=0.000456168 z=485mm, γ=0.000467866 From equation (12), the shear deformation when R=+0.5% is δ s =0.33mm. (2) γ at each z position when R=+1.0% is as follows: z=55mm, γ=0.0006391 z=270mm, γ=0.000747933 z=485mm, γ=0.000746043 From equation (12), the shear deformation when R=+1.0% is δ s =0.53mm.

[0046] In the joint structure between a CFT column and an RC column configured in this way, the shear deformation in the joint steel pipe part can be calculated from the shear strain in the steel pipe part of the CFT column measured during the experiment.

[0047] The above describes one embodiment of the joint structure between a CFT column and an RC column according to the present invention, but the present invention is not limited to the above embodiment and can be modified as appropriate within the scope of its intent. [Explanation of symbols]

[0048] 1a Lower part 1b upper management 2 CFT columns 3 RC pillar 4 Steel beams 5 Steel pipe 6 Jointed steel pipe 7 Main reinforcement 8. Concrete 9 Stiffening part 10 Fixing plate 20 Joint structure between CFT column and RC column

Claims

[Claim 1] A joint structure between a CFT column and an RC column that joins a CFT column and an RC column arranged above the CFT column, A joint steel pipe formed so as to extend upward is provided at the upper end of the CFT column, The main reinforcement of the RC column is inserted into the connecting steel pipe, and concrete is filled into the connecting steel pipe. A stiffening portion protruding inward from the inner surface is provided at the upper end of the joined steel pipe, An anchor plate is provided at the lower end of the main reinforcement, The shear deformation of the joint steel pipe was measured during the experiment as x = -x ０ , 0, x ０ The shear strain at ε γ１ , ε γ０ , ε γ２ and expressed as in equation (1): The shear deformation angle γ is expressed by equation (2), β is calculated from equation (1), and this is substituted into equation (2) to calculate γ. Then, γ at Δz is calculated by multiplying the joining steel pipe height H Ｓ By integrating in the direction, the shear deformation δ ｓ Calculation of the joint structure between a CFT column and an RC column. [Equation 1]

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