Lateral load-displacement curve calculation method for partially filled steel tube concrete column

Abstract

The invention discloses a method for calculating a lateral load-displacement curve of a partially filled steel tube concrete column. The method comprises the following steps: acquiring basic parameters of the partially filled steel tube concrete column; analyzing the stress condition of the partially filled steel tube concrete column; constructing a lateral displacement calculation model of each change stage; establishing a relation curve of the lateral load and the lateral displacement of each change stage according to the lateral load and the lateral displacement, and fitting the relation curve of each stage to obtain a lateral load-displacement curve of the partially filled steel tube concrete column. According to the calculation method, a data basis is provided for accurately evaluating the anti-seismic property of the partially-filled steel tube concrete column component, and finally a calculation basis is provided for application of the partially-filled steel tube concrete column in actual engineering; and the calculation method is relatively simple, data is easy to obtain and measure, and the current rapid design requirement can be well met.

Description

Technical Field

[0001] The present invention belongs to the technical field of steel - concrete composite structures, and relates to a concrete - filled steel tube and its design method, specifically to a calculation method for the lateral load - displacement curve of a partially concrete - filled steel tube column. Background Art

[0002] In recent years, with the development of high - rise buildings and long - span structures, concrete - filled steel tube columns have been widely used in modern building structures due to their good load - bearing capacity and seismic performance. As a special form, the proportion of concrete filled in the core part of a partially concrete - filled steel tube column is different from that of traditional fully filled or hollow concrete - filled steel tube columns, so special consideration is needed in design and analysis.

[0003] Currently, for the mechanical behavior analysis of partially concrete - filled steel tube columns, methods such as finite element analysis and experimental research are usually adopted. However, these methods often require complex modeling processes and a large amount of computing resources, which are not convenient for engineering practice.

[0004] In the prior art, the acquisition of the lateral load - lateral displacement curve mainly relies on experimental data or complex numerical simulations, which leads to the following problems:

[0005] (1) The experimental cost is high and the cycle is long, making it difficult to meet the needs of rapid design;

[0006] (2) Numerical simulations often require professional knowledge and software support, which are relatively complex for general engineers. Summary of the Invention

[0007] The purpose of the present invention is to provide a calculation method for the lateral load - displacement curve of a partially concrete - filled steel tube column in view of the problems existing in the prior art.

[0008] To achieve the above - mentioned purpose, the technical solution adopted by the present invention is:

[0009] A calculation method for the lateral load - displacement curve of a partially concrete - filled steel tube column, the calculation method comprising the following steps:

[0010] Obtain the basic parameters of the partially concrete - filled steel tube column, including at least the total height of the partially concrete - filled steel tube column, the height of the hollow steel tube section, and the position and magnitude of the lateral load applied; the lower part of the partially concrete - filled steel tube column is a solid concrete section, and the upper part is a hollow steel tube section;

[0011] Analyze the stress condition of the partially concrete - filled steel tube column, and divide the change stages of the partially concrete - filled steel tube column according to the stress condition. The change stages successively include an initial elastic stage, a post - yield elastic stage, a plastic development stage, and a failure stage;

[0012] Construct a lateral displacement calculation model for each of the said change stages, and calculate and obtain the lateral displacement of each of the said change stages respectively according to the lateral displacement calculation model;

[0013] Establish a relationship curve between the lateral load and the lateral displacement for each of the said change stages according to the lateral load and the lateral displacement, and fit the relationship curve of each stage to obtain the lateral load-displacement curve of the partially filled concrete-filled steel tubular column.

[0014] This calculation method provides a data basis for accurately evaluating the seismic performance of partially filled concrete-filled steel tubular column members by accurately calculating the lateral load-lateral displacement curve of partially filled concrete-filled steel tubular column members, and finally provides a calculation basis for the application of partially filled concrete-filled steel tubular columns in practical engineering; it solves the problem of the lack of applicable models when using partially filled concrete-filled steel tubular column members for design checking under lateral loads, and this calculation method is relatively simple, and the data is easy to obtain and measure, and can better meet the requirements of current rapid design.

[0015] Furthermore, in each of the said change stages, continuously monitor the magnitude of the lateral load respectively, obtain the maximum lateral load in each of the said change stages, calculate the maximum lateral displacement under the maximum lateral load, and calculate the curve slope of each change stage according to the maximum lateral load and the maximum lateral displacement.

[0016] Furthermore, according to the curve slope, establish a function model between the lateral load and the lateral displacement under each change stage, with the lateral displacement as the abscissa and the lateral load as the ordinate, and based on the function model and the maximum lateral displacement value and the maximum lateral load value of each stage, establish the relationship curve, and connect the relationship curves in sequence to obtain a complete and continuous lateral load-displacement curve.

[0017] Furthermore, in the post-yield elastic stage, local yielding occurs in the hollow stage of the steel pipe, but no plastic hinge is formed, and the control section of the partially filled concrete-filled steel tubular column becomes the solid section at the bottom of the partially filled concrete-filled steel tubular column.

[0018] Furthermore, in the plastic development stage, both the hollow section and the solid section of the partially filled concrete-filled steel tubular column yield, and in the failure stage, the bearing capacity of the partially filled concrete-filled steel tubular column begins to decline, and the failure stage ends when it drops to 85% of the maximum load.

[0019] Furthermore, the regional division and function model of each of the said change stages are as follows:

[0020] When in the initial elastic stage, ;

[0021] When in the post-yield elastic stage, ;

[0022] When in the plastic development stage, ;

[0023] When in the failure stage, ;

[0024] Wherein, P is the lateral load, Δ is the lateral displacement, Δ1 is the maximum lateral displacement in the initial elastic stage, k1 is the curve slope in the initial elastic stage, Δ2 is the maximum lateral displacement in the post-yield elastic stage, k2 is the curve slope in the post-yield elastic stage, Δ3 is the maximum lateral displacement in the plastic development stage, Δ4 is the maximum lateral displacement in the failure stage of the concrete-filled steel tube column, and k4 is the curve slope in the failure stage.

[0025] Furthermore, in the initial elastic stage, its lateral displacement calculation model is: ,

[0026] Its maximum lateral load calculation model is: , where ;

[0027] Thus, the curve slope k1 in the initial elastic stage is calculated as: ;

[0028] Wherein, P1 is the maximum lateral load in the initial elastic stage, Δ1 is the maximum lateral displacement in the initial elastic stage, β1 is the load transfer coefficient in the initial elastic stage, W sc,h is the section modulus of the hollow concrete-filled steel tube section, f is the yield strength of the steel tube, H h is the height of the steel tube hollow section, β2 is the strain distribution coefficient in the initial elastic stage, ε y is the yield strain of the steel tube, r0 is the radius of the partially filled concrete-filled steel tube column, r h is the hollow radius of the partially filled concrete-filled steel tube column.

[0029] Furthermore, in the post-yield elastic stage, its lateral displacement calculation model is: ,

[0030] Its maximum lateral load calculation model is: , where , , ;

[0031] Thus, the curve slope k2 in the post-yield elastic stage is calculated as: ;

[0032] Wherein, P2 is the maximum lateral load in the post-yield elastic stage, β3 is the load transfer coefficient in the post-yield elastic stage, Δ2 is the maximum lateral displacement in the post-yield elastic stage, β4 is the strain distribution coefficient in the post-yield elastic stage, and γ m is the plastic development coefficient of the solid cross-section of the partially filled concrete-filled steel tube column, and W sc,s is the section modulus of the solid cross-section of the partially filled concrete-filled steel tube column, and f sc is the compressive strength of the solid concrete segment in the partially filled concrete-filled steel tube column, and H t is the total height of the partially filled concrete-filled steel tube column, and f c is the compressive strength of concrete, θ is the confinement coefficient of the solid concrete segment, and A s and A c are the areas of the steel tube and the concrete inside the tube, respectively.

[0033] Furthermore, in the plastic development stage, its lateral displacement calculation model is: ,

[0034] wherein, , ,

[0035] In the formula, Δ3 is the maximum lateral displacement in the plastic development stage, w1 is the weight coefficient of the plastic development of the cross-section of the hollow steel tube segment, and Δ 1u is the maximum lateral displacement corresponding to the failure of the hollow steel tube segment, w2 is the weight coefficient of the plastic development of the cross-section of the solid concrete segment, and Δ 2u is the maximum lateral displacement corresponding to the failure of the solid concrete segment, and ε su is the ultimate strain of the steel of the steel tube.

[0036] Furthermore, in the failure stage, its lateral displacement calculation model is: ,

[0037] Its maximum lateral load calculation model is: ,

[0038] Thus, calculate the curve slope k4 in the initial elastic stage: ;

[0039] In the formula, k4 is the curve slope in the failure stage, P4 is the final lateral load in the failure stage, β5 is the load coefficient at failure, β6 is the displacement coefficient at failure, and Δ4 is the maximum lateral displacement in the failure stage of the partially filled concrete-filled steel tube column.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The calculation method of the present invention accurately calculates the lateral load-lateral displacement curve of partially filled concrete-filled steel tubular column members, providing a data basis for accurately evaluating the seismic performance of partially filled concrete-filled steel tubular column members, and ultimately providing a calculation basis for the application of partially filled concrete-filled steel tubular columns in practical engineering; it solves the problem of the lack of applicable models when designing and checking the bearing capacity of partially filled concrete-filled steel tubular column members under lateral loads. Moreover, this calculation method is relatively simple, and the data is easy to obtain and measure, which can better meet the current requirements of rapid design; 2. High calculation efficiency, capable of giving accurate results in a short time, thus greatly improving the design efficiency of engineers; compared with traditional experimental tests or complex numerical simulations, the present invention can significantly reduce the required calculation resources and time costs; 3. It can well improve the prediction accuracy and more accurately predict the behavior of partially filled concrete-filled steel tubular columns under lateral loads, which is crucial for the safety and economy of structures; 4. It has strong applicability and can be applied to different types of concrete-filled steel tubular column structures, including different filling ratios, thus broadening its application scope. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic structural diagram of the partially filled concrete-filled steel tubular column of the present invention;

[0042] Figure 2 It is a schematic diagram of the comparison between the curve obtained by the calculation method of the present invention and the test curve; DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the drawings in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

[0044] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "middle", "upper", "lower", "left", "right", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0045] A calculation method for the lateral load-displacement curve of a partially filled concrete-filled steel tubular column, the calculation method comprising the following steps:

[0046] Step 1: Obtain the basic parameters of the partially filled concrete-filled steel tubular column, including at least the total height of the partially filled concrete-filled steel tubular column, the height of the steel pipe hollow section, and the position and magnitude of the lateral load application; the lower part of the partially filled concrete-filled steel tubular column is a solid concrete section, and the upper part is a steel pipe hollow section, and the lateral load application position is on one side of the end of the steel pipe hollow section.

[0047] Step 2: Analyze the stress condition of the partially filled concrete-filled steel tubular column, and divide the change stages of the partially filled concrete-filled steel tubular column according to the stress condition. The change stages successively include the initial elastic stage, the post-yield elastic stage, the plastic development stage, and the failure stage.

[0048] In the post-yield elastic stage, the steel pipe hollow section is locally yielded but no plastic hinge is formed, and the control section of the partially filled concrete-filled steel tubular column becomes the solid section at the bottom of the partially filled concrete-filled steel tubular column.

[0049] In the plastic development stage, both the hollow section and the solid section of the partially filled concrete-filled steel tubular column are yielded. In the failure stage, the bearing capacity of the partially filled concrete-filled steel tubular column begins to decline, and the failure stage ends when it drops to 85% of the maximum load.

[0050] Step 3: Construct a lateral displacement calculation model for each of the change stages, and calculate and obtain the lateral displacement of each of the change stages according to the lateral displacement calculation model respectively.

[0051] In each of the change stages, continuously monitor the magnitude of the lateral load respectively, obtain the maximum lateral load in each of the change stages, calculate the maximum lateral displacement under the maximum lateral load according to the lateral displacement calculation model. The ratio of the maximum lateral load to the maximum lateral displacement can be used to characterize the curve slope of each change stage, and the curve slope can be used to construct a relationship curve.

[0052] Step 4: Establish a relationship curve between the lateral load and the lateral displacement for each of the change stages according to the lateral load and the lateral displacement, and fit the relationship curve of each stage to obtain the lateral load-displacement curve of the partially filled concrete-filled steel tubular column.

[0053] Through the first three steps, the numerical values of the maximum lateral load and the maximum lateral displacement at each change stage, as well as the corresponding curve slopes, can be calculated by the calculation model respectively. In this way, the relationship curves at each change stage can be constructed respectively, that is, the lateral load-lateral displacement curve in the initial elastic stage, the lateral load-lateral displacement curve in the post-yield elastic stage, the lateral load-lateral displacement curve in the plastic development stage, and the lateral load-lateral displacement curve in the failure stage. Fitting these four sections of lateral load-lateral displacement curves in the same coordinate system can obtain the lateral load-displacement curve of the entire partially filled concrete-filled steel tubular column.

[0054] This calculation method of the present invention provides a data basis for accurately evaluating the seismic performance of partially filled concrete-filled steel tubular column members by accurately calculating the lateral load-lateral displacement curve of partially filled concrete-filled steel tubular column members, and finally provides a calculation basis for the application of partially filled concrete-filled steel tubular columns in practical engineering; it solves the problem of the lack of applicable models when designing and checking the bearing lateral load of partially filled concrete-filled steel tubular column members at present, and this calculation method is relatively simple, and the data is easy to obtain and measure, which can better meet the needs of current rapid design.

[0055] This calculation method of the present invention also has the characteristic of high calculation efficiency, and can give accurate results in a short time, thus greatly improving the design efficiency of engineers; compared with traditional experimental tests or complex numerical simulations, the present invention can significantly reduce the required calculation resources and time costs.

[0056] This calculation method of the present invention can well improve the prediction accuracy and more accurately predict the behavior of partially filled concrete-filled steel tubular columns under lateral loads, which is crucial for the safety and economy of structures.

[0057] In addition, this technical method of the present invention has strong applicability and can be applied to different types of concrete-filled steel tubular column structures, including different filling ratios, thus broadening its application scope.

[0058] Furthermore, by analyzing the force characteristics and limit points at each change stage, the regions at each change stage can be divided according to the change range of lateral displacement. After division, function models can be established respectively. These function models provide the most direct basis for the construction of curves, and these function models are as follows:

[0059] When in the initial elastic stage, ;

[0060] When in the post-yield elastic stage, ;

[0061] When in the plastic development stage, ;

[0062] When in the said damage stage, ;

[0063] Wherein, P is the lateral load in each stage, with the unit of N; Δ is the lateral displacement, with the unit of mm; Δ1 is the maximum lateral displacement in the initial elastic stage, with the unit of mm; k1 is the curve slope in the initial elastic stage, Δ2 is the maximum lateral displacement in the post-yield elastic stage, with the unit of mm; k2 is the curve slope in the post-yield elastic stage, Δ3 is the maximum lateral displacement in the plastic development stage, with the unit of mm; Δ4 is the maximum lateral displacement in the damage stage of the concrete-filled steel tubular column, with the unit of mm; k4 is the curve slope in the damage stage; P1 is the maximum lateral load in the initial elastic stage, with the unit of N; P2 is the maximum lateral load in the post-yield elastic stage, with the unit of N.

[0064] To further understand this calculation method, here in combination with Figure 1 , the reference implementation structure and calculation process are further described as follows.

[0065] First, calculate the modulus W of the hollow cross-section of the steel pipe (the cross-section of the concrete-filled steel tube) according to the following formula sc,h :

[0066] ,

[0067] Wherein, r0 is the radius of the concrete-filled steel tubular column, with the unit of mm; r h is the hollow radius, with the unit of mm.

[0068] Calculate the maximum lateral load P1 in the initial elastic stage according to the following formula:

[0069] ,

[0070] Wherein, β1 is the load transfer coefficient, with a value of 0.38; f is the yield strength of the steel pipe, with the unit of MPa; H h is the height of the hollow section of the steel pipe, with the unit of mm.

[0071] Calculate the maximum lateral displacement Δ1 in the initial elastic stage according to the following formula:

[0072] ,

[0073] Wherein, β2 is the strain distribution coefficient, with a value of 0.09; ε y is the yield strain of the steel pipe.

[0074] Thus, the curve slope k1 in the initial elastic stage can be calculated: , substituting the obtained specific data values can obtain the numerical value of the curve slope k1.

[0075] Secondly, calculate the section modulus W of the solid section of the steel pipe (i.e., the solid section of the partially filled concrete-filled steel tubular column) according to the following formula sc,s :

[0076] ,

[0077] Calculate the confinement coefficient θ of the solid concrete-filled steel tubular member according to the following formula

[0078] ,

[0079] In the formula, f c is the compressive strength of concrete, with the unit of MPa; θ is the confinement coefficient of the solid concrete-filled steel tubular member; A s , A c are the areas of the steel pipe and the concrete inside the pipe respectively, with the unit of mm 2 .

[0080] Calculate the compressive strength f of the solid concrete-filled steel tubular section according to the following formula sc :

[0081] ,

[0082] Calculate the maximum lateral load P2 in the elastic stage after yielding according to the following formula

[0083] ,

[0084] In the formula, β3 is the load transfer coefficient in the elastic stage after yielding, with a value of 0.65; γ m is the plastic development coefficient of the solid section, with a value of 1.2; H t is the total height of the concrete-filled steel tubular column, with the unit of mm

[0085] Calculate the maximum lateral displacement Δ2 in the elastic stage after yielding according to the following formula

[0086] ,

[0087] In the formula, β4 is the strain distribution coefficient in the elastic stage after yielding, with a value of 0.25

[0088] Thus, the curve slope k2 in the elastic stage after yielding can be calculated . Substitute the specific data values obtained to get the numerical value of the curve slope k2

[0089] Thirdly, calculate the maximum lateral displacement Δ corresponding to the failure of the hollow steel pipe according to the following formula 1u :

[0090] ,

[0091] where ε su is the ultimate strain of the steel pipe steel.

[0092] Calculate the maximum lateral displacement Δ corresponding to the failure of the solid steel pipe according to the following formula 2u :[[]]

[0093] ,

[0094] Calculate the maximum lateral displacement Δ3 in the plastic development stage according to the following formula:

[0095] ,

[0096] where w1 is the weight coefficient of the plastic development of the hollow steel pipe section, with a value of 0.3; w2 is the weight coefficient of the plastic development of the solid steel pipe section, with a value of 0.7.

[0097] In the plastic development stage, the curve slope is 1, and the maximum lateral load P in the elastic stage after yielding has been calculated previously 2， At this time, it is only necessary to calculate the maximum lateral displacement in the plastic development stage, so that the coordinate points can be determined.

[0098] Fourth, calculate the final lateral load P4 in the failure stage according to the following formula:

[0099] ,

[0100] where β5 is the load coefficient at failure, with a value of 0.85.

[0101] Calculate the maximum lateral displacement Δ4 of the concrete-filled steel tube column in the failure stage according to the following formula:

[0102] ,

[0103] where β6 is the displacement coefficient at failure, with a value of 1.25.

[0104] Thus, the curve slope k4 in the failure stage can be calculated: , and substituting the obtained specific data values can obtain the numerical value of the curve slope k4.

[0105] Finally, according to the numerical values of the curve slope k1, curve slope k2, curve slope k3 and curve slope k4, and the coordinate points of the combination of the maximum lateral displacement and the maximum lateral load in each change stage, construct a change curve in the same coordinate system to obtain the lateral load-displacement curve of the partially concrete-filled steel tube column required.

[0106] The experimental parameters and results in the article "Experimental Study on the Influence of Concrete Filling Height on the Seismic Performance of Partially Filled Circular Concrete-Filled Steel Tubular Bridge Piers" published by Wang Zhanfei et al. in "Bridge and Tunnel Engineering" are adopted to verify the present invention. The data extracted and summarized from the article are shown in Table 1 below.

[0107] Table 1: Experimental Parameter Data

[0108]

[0109] Through the curve calculation method of the present invention, the lateral load-lateral displacement curve of Specimen A27-75-33 is calculated and compared with the test results. As Figure 2 shown, it can be seen that the calculated curve of the present invention is in good agreement with the actual test curve.

[0110] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for calculating lateral load-displacement curves of partially filled concrete-filled steel tube columns, characterized in that: The calculation method comprises the following steps: Obtaining basic parameters of a partially filled steel tube concrete column, including at least the total height of the partially filled steel tube concrete column, the height of the hollow steel tube segment, and the position and magnitude of lateral load application; Analyze the stress condition of the partially filled steel tube concrete column, and divide the change stages of the partially filled steel tube concrete column according to the stress condition, wherein the change stages sequentially include an initial elastic stage, a post-yield elastic stage, a plastic development stage, and a destruction stage; Constructing a lateral displacement calculation model for each of the change stages, and calculating and obtaining the lateral displacement for each of the change stages according to the lateral displacement calculation model; A relationship curve between the lateral load and the lateral displacement in each of the change stages is established according to the lateral load and the lateral displacement, and a lateral load-displacement curve of the partially filled steel tube concrete column is obtained by fitting the relationship curve in each stage.

2. The method for calculating lateral load-displacement curve of partially filled steel tube concrete column according to claim 1, characterized in that: In each of the change stages, the size of the lateral load is continuously monitored, the maximum lateral load in each of the change stages is obtained, the maximum lateral displacement under the maximum lateral load is calculated, and the slope of the curve in each change stage is calculated according to the maximum lateral load and the maximum lateral displacement.

3. The method for calculating lateral load-displacement curve of partially filled steel tube concrete column according to claim 2, characterized in that: According to the slope of the curve, a function model of the lateral load and the lateral displacement in each change stage is established, with the lateral displacement as the horizontal coordinate and the lateral load as the vertical coordinate. Based on the function model and the maximum lateral displacement value and the maximum lateral load value in each stage, the relationship curve is established, and the relationship curves are connected in sequence to obtain a complete and continuous lateral load-displacement curve.

4. The method for calculating lateral load-displacement curve of partially filled steel tube concrete column according to claim 1, characterized in that: The post-yield elastic stage is the local yield of the hollow steel tube stage, but no plastic hinge is formed, and the control section of the partially filled steel tube concrete column becomes the solid section at the bottom of the partially filled steel tube concrete column.

5. The method for calculating lateral load-displacement curve of partially filled concrete-filled steel tube columns according to claim 1, characterized in that: The plastic development stage is when both the hollow section and the solid section of the partially filled steel tube concrete column yield, and in the destruction stage, the bearing capacity of the partially filled steel tube concrete column begins to decrease, and the destruction stage ends when it decreases to 85% of the maximum load.

6. The method for calculating lateral load-displacement curve of partially filled steel tube concrete column according to claim 1, 2 or 3, characterized in that: The regional division and function model of each change stage are as follows: In the initial elastic stage, ; In the post-yield elastic stage, ; When in the plastic development stage, ; In the destruction stage, ; Where P is the lateral load, Δ is the lateral displacement, Δ1 is the maximum lateral displacement in the initial elastic stage, k1 is the slope of the curve in the initial elastic stage, Δ2 is the maximum lateral displacement in the elastic stage after yielding, k2 is the slope of the curve in the elastic stage after yielding, Δ3 is the maximum lateral displacement in the plastic development stage, Δ4 is ​​the maximum lateral displacement in the failure stage of the CFST column, and k4 is the slope of the curve in the failure stage.

7. The method for calculating lateral load-displacement curve of partially filled steel tube concrete column according to claim 1, characterized in that: In the initial elastic stage, the lateral displacement calculation model is: , The calculation model of its maximum lateral load is: ,in ; The slope k1 of the curve in the initial elastic stage is calculated from this: ; Where P1 is the maximum lateral load in the initial elastic stage, Δ1 is the maximum lateral displacement in the initial elastic stage, β1 is the load transfer coefficient in the initial elastic stage, and W is sc,h is the section modulus of the hollow steel tube concrete section, f is the yield strength of the steel tube, H h is the height of the hollow section of the steel tube, β2 is the strain distribution coefficient in the initial elastic stage, ε y is the yield strain of the steel tube, r0 is the radius of the partially filled steel tube concrete column, r h The hollow radius of the partially filled concrete-filled steel tube column.

8. The method for calculating lateral load-displacement curve of partially filled steel tube concrete column according to claim 1, characterized in that: In the post-yield elastic stage, the lateral displacement calculation model is: , The calculation model of its maximum lateral load is: ,in , , ; The slope k2 of the curve in the elastic stage after yielding is calculated from this: ; Where P2 is the maximum lateral load in the elastic stage after yielding, β3 is the load transfer coefficient in the elastic stage after yielding, Δ2 is the maximum lateral displacement in the elastic stage after yielding, β4 is the strain distribution coefficient in the elastic stage after yielding, and γ m is the plastic development coefficient of the solid section of the partially filled concrete filled steel tube column, W sc,s is the section modulus of the solid section of the partially filled concrete filled steel tube column, f sc is the compressive strength of the solid concrete segment in the partially filled concrete-filled steel tube column, H t is the total height of the partially filled CFST column, f c is the concrete compressive strength, θ is the hoop coefficient of the solid concrete segment, A s , A c are the areas of the steel pipe and the concrete inside the pipe respectively.

9. The method for calculating lateral load-displacement curve of partially filled steel tube concrete column according to claim 1, characterized in that: In the plastic development stage, the lateral displacement calculation model is: , in, , , Where Δ3 is the maximum lateral displacement in the plastic development stage, w1 is the weight coefficient of the hollow section of the steel tube for plastic development, Δ 1u is the maximum lateral displacement corresponding to the failure of the hollow steel tube segment, w2 is the weight coefficient of the solid concrete segment section for plastic development, Δ 2u is the maximum lateral displacement corresponding to the failure of the solid concrete segment, ε su is the ultimate strain of steel pipe steel.

10. The method for calculating lateral load-displacement curve of partially filled steel tube concrete column according to claim 1, characterized in that: In the destruction stage, the lateral displacement calculation model is: , The calculation model of its maximum lateral load is: , The slope k4 of the curve in the initial elastic stage is calculated from this: ; Wherein, k4 is the slope of the curve at the failure stage, P4 is the final lateral load at the failure stage, β5 is the load coefficient at failure, β6 is the displacement coefficient at failure, and Δ4 is ​​the maximum lateral displacement of the partially filled steel tube concrete column at the failure stage.

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