Super high-rise building concrete filled steel tube member optimization design method considering eccentric compression

Abstract

The invention relates to a super high-rise building steel pipe concrete member optimization design method considering eccentric compression. The method comprises the steps that finite element analysis software is adopted to establish a finite element model of an eccentric compression steel pipe concrete member in a super high-rise building; calculating the corrected constraint force of the steel pipe on the core concrete based on the finite element model; the corrected constraint force obtained through calculation is substituted into an axial compression constitutive model of the concrete-filled steel tube member, and a concrete-filled steel tube analysis model considering the gradient effect caused by the eccentric load is established; and the concrete-filled steel tube analysis model is called to correct the compressive strength design value of the core concrete to obtain a compressive strength correction value, and then the ultimate bearing capacity of the concrete-filled steel tube member is calculated according to the compressive strength correction value. According to the method, the influence of the eccentric load on the constraining force of the concrete-filled steel tube member can be more comprehensively considered, so that the mechanical property of the concrete-filled steel tube member under the action of the eccentric load is more accurately predicted, and the optimal design of the concrete-filled steel tube member is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of super high-rise buildings, and particularly to an optimized design method for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression. Background Art

[0002] In super high-rise buildings, concrete-filled steel tubular columns have been widely used due to their excellent composite action, strength, seismic performance, fire resistance and construction convenience. However, concrete-filled steel tubular columns are often in a complex stress state in actual projects, especially under eccentric loading, and their mechanism is different from that under axial loading. Existing research mainly focuses on the compressive performance under axial compression, and the research on the mechanical mechanism and long-term performance under eccentric compression still needs to be deepened. Therefore, it is necessary to develop an optimized design method for concrete-filled steel tubular members considering eccentric compression to provide a more accurate and reliable basis for engineering design and analysis to meet the complex and variable engineering requirements of super high-rise buildings. Summary of the Invention

[0003] The purpose of the present invention is to provide an optimized design method for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression, which can more comprehensively consider the influence of eccentric load on the binding force of concrete-filled steel tubular members, provide a more accurate and reliable basis for engineering design and analysis, and meet the complex and variable engineering requirements of super high-rise buildings.

[0004] To achieve the above object, the present invention provides an optimized design method for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression, including:

[0005] According to the design drawings, a finite element model of the concrete-filled steel tubular member under eccentric compression in a super high-rise building is established by using finite element analysis software, and the boundary conditions and load conditions are reasonably set. The finite element model includes two parts: a steel pipe and core concrete;

[0006] Based on the finite element model, the corrected binding force of the steel pipe on the core concrete is calculated;

[0007] The calculated corrected binding force is substituted into the axial compression constitutive model of the concrete-filled steel tubular member, and a gradient effect analysis model is introduced in the design of the concrete-filled steel tubular member to consider the uneven stress caused by the eccentric load, and a concrete-filled steel tubular analysis model considering the gradient effect caused by the eccentric load is established;

[0008] The concrete-filled steel tubular analysis model is called to correct the design value of the compressive strength of the core concrete to obtain a corrected compressive strength value, and then the ultimate bearing capacity of the concrete-filled steel tubular member is calculated according to the corrected compressive strength value, so as to realize the optimized design of the concrete-filled steel tubular member.

[0009] Optionally, the binding force of the core concrete varies linearly along the eccentricity direction within the cross-section range and remains constant in the direction perpendicular to the eccentricity.

[0010] Optionally, the formula for calculating the modified binding force of the steel pipe on the core concrete based on the finite element model is as follows:

[0011]

[0012] In the formula, f lg is the modified binding force; D c is the diameter of the core concrete; f l is the binding force of the steel pipe on the core concrete before modification; e is the eccentricity; V e and P e are calculation parameters.

[0013] Optionally, the concrete-filled steel tube analysis model is as follows:

[0014]

[0015] f c ' c = f c '+ 4.1f 1g ,

[0016]

[0017] In the formula, σ and ε are the stress and strain that constrain the core concrete; f c ′ and ε c ′ represent the uniaxial compressive strength and the corresponding strain; f′ cc and ε′ cc represent the compressive strength and the corresponding strain of the core concrete strengthened by the binding force; E c represents the initial elastic modulus of the core concrete; k3 is the material degradation parameter, which is used to represent the strength degradation of the material; f lg is the modified binding force; f l is the binding force of the steel pipe on the core concrete before modification;

[0018] Among them, the calculation formulas for the f l and the k3 are as follows:

[0019]

[0020] In the formula, D is the diameter of the steel pipe; t is the thickness of the steel pipe; f y is the yield strength of the steel pipe.

[0021] Optionally, the formula for correcting the design value of the compressive strength of the core concrete by invoking the concrete-filled steel tube analysis model is as follows:

[0022] f cx = k1f c ;

[0023]

[0024] In the formula, f cx is the corrected compressive strength; f c is the design value of the compressive strength of the core concrete; f′ cc1 is the concrete compressive strength when the eccentricity is 0; f′ cc2 is the concrete compressive strength when the eccentricity is e; k1 is the correction coefficient;

[0025] The formula for calculating the ultimate bearing capacity of the concrete-filled steel tube member according to the compressive strength correction value is as follows:

[0026]

[0027] And in any case, the following formula condition should be satisfied:

[0028]

[0029] In the formula, N u is the ultimate bearing capacity of the concrete-filled steel tube member; θ is the confinement coefficient of the concrete-filled steel tube member; α is the coefficient related to the strength grade of the core concrete; A c is the cross-sectional area of the core concrete; f c is the design value of the compressive strength of the core concrete; A s is the cross-sectional area of the steel tube; f is the design value of the compressive strength of the steel tube; is the bearing capacity reduction coefficient considering the influence of eccentricity; is the bearing capacity reduction coefficient considering the influence of slenderness ratio; is the value that should be considered as an axially compressed column.

[0030] Optionally, before correcting the design value of the compressive strength of the core concrete by invoking the concrete-filled steel tube analysis model, the design method further includes:

[0031] Obtaining the load-displacement curve of the concrete-filled steel tube member based on the concrete-filled steel tube analysis model;

[0032] Performing simulation on the finite element model, fabricating a number of concrete-filled steel tube specimens for axial compression and eccentric compression tests, obtaining the corresponding load-displacement curves and comparing the test results.

[0033] Based on the same inventive concept, the present invention further provides an optimized design system for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression, which is used to implement the optimized design method for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression as described above, including:

[0034] A first model construction module, configured to establish a finite element model of a concrete-filled steel tubular member under eccentric compression in a super high-rise building by using finite element analysis software according to design drawings, and reasonably set boundary conditions and load conditions, where the finite element model includes two parts: steel pipe and core concrete;

[0035] A calculation module, configured to calculate the corrected binding force of the steel pipe on the core concrete based on the finite element model;

[0036] A second model construction module, configured to substitute the calculated corrected binding force into the axial compression constitutive model of the concrete-filled steel tubular member, introduce a gradient effect analysis model in the design of the concrete-filled steel tubular member, consider the uneven stress caused by the eccentric load, and establish a concrete-filled steel tubular analysis model considering the gradient effect caused by the eccentric load;

[0037] A correction module, configured to call the concrete-filled steel tubular analysis model to correct the design value of the compressive strength of the core concrete to obtain a corrected compressive strength value, and then calculate the ultimate bearing capacity of the concrete-filled steel tubular member according to the corrected compressive strength value, so as to realize the optimized design of the concrete-filled steel tubular member.

[0038] Optionally, the binding force of the core concrete varies linearly along the eccentric distance direction within the cross-section range and remains constant in the direction perpendicular to the eccentric distance.

[0039] Optionally, the design system further includes a simulation module, and the simulation module is configured to:

[0040] Obtain the load-displacement curve of the concrete-filled steel tubular member based on the concrete-filled steel tubular analysis model;

[0041] Perform a simulation on the finite element model, fabricate several concrete-filled steel tubular specimens for axial compression and eccentric compression tests, obtain the corresponding load-displacement curves and compare the test results.

[0042] Based on the same inventive concept, the present invention further provides a readable storage medium, on which a computer program is stored, and when the computer program is executed, it can implement the optimized design method for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression as described above.

[0043] In an optimized design method for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression provided by the present invention, the axial compression constitutive model of existing concrete-filled steel tubular members is corrected by introducing the load eccentricity effect, which can more comprehensively consider the influence of eccentric loads on the binding force of concrete-filled steel tubular members, and is further used to correct the design value of the compressive strength and the design value of the ultimate bearing capacity in the existing specifications, so as to more accurately predict the mechanical properties of the concrete-filled steel tubular members under eccentric loads and realize the optimized design of concrete-filled steel tubular members in super high-rise buildings. Description of the Drawings

[0044] Those of ordinary skill in the art will understand that the provided drawings are used to better understand the present invention and do not constitute any limitation to the scope of the present invention. Among them:

[0045] Figure 1 is a flowchart of an optimized design method for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression provided by an embodiment of the present invention;

[0046] Figure 2 is a schematic diagram of the calculation of the binding force of the core concrete under compression of the entire cross-section provided by an embodiment of the present invention;

[0047] Figure 3 is a schematic diagram of the calculation of the binding force of the core concrete with partial cross-section compression provided by an embodiment of the present invention;

[0048] Figure 4 is a schematic diagram of the relationship between the corrected binding force and eccentricity provided by an embodiment of the present invention;

[0049] Figure 5 is a schematic diagram of the relationship between the stress-strain curve of the core concrete and the corrected binding force provided by an embodiment of the present invention;

[0050] Figure 6 is a comparison diagram of the confined concrete curve and the unconfined concrete curve under general conditions provided by an embodiment of the present invention;

[0051] Figure 7 is a finite element model provided by an embodiment of the present invention;

[0052] Figure 8 is Figure 7 a schematic diagram of the calculation results of the provided finite element model. Detailed Embodiments

[0053] To make the objectives, advantages, and features of the present invention clearer, the following further describes the present invention in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the accompanying drawings are in a very simplified form and use non-precise scales, only for conveniently and clearly assisting in explaining the objectives of the embodiments of the present invention. To make the objectives, features, and advantages of the present invention more obvious and understandable, please refer to the accompanying drawings. It should be noted that the structures, scales, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Any modification of the structure, change in the proportional relationship, or adjustment of the size, in the case of being the same or similar to the effects that the present invention can produce and the objectives that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention.

[0054] As used in the present invention, the singular forms "a", "an", and "the" include plural objects unless the context clearly indicates otherwise. As used in the present invention, the term "or" is generally used in the sense of including "and / or" unless the context clearly indicates otherwise. As used in the present invention, the term "several" is generally used in the sense of including "at least one" unless the context clearly indicates otherwise. As used in the present invention, the term "at least two" is generally used in the sense of including "two or more" unless the context clearly indicates otherwise.

[0055] Please refer to Figure 1 , an optimized design method for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression is provided in an embodiment of the present invention, including the following steps:

[0056] S1. According to the design drawings, use finite element analysis software to establish a finite element model of the concrete-filled steel tubular member under eccentric compression in a super high-rise building, and reasonably set boundary conditions and load conditions. The finite element model includes two parts: a steel pipe and core concrete;

[0057] S2. Calculate the corrected binding force of the steel pipe on the core concrete based on the finite element model;

[0058] S3. Substitute the calculated corrected binding force into the axial compression constitutive model of the concrete-filled steel tubular member, introduce a gradient effect analysis model in the design of the concrete-filled steel tubular member, consider the non-uniform stress caused by the eccentric load, and establish a concrete-filled steel tubular analysis model considering the gradient effect caused by the eccentric load;

[0059] S4. Call the concrete-filled steel tube analysis model to correct the design value of the compressive strength of the core concrete to obtain a corrected compressive strength value, and then calculate the ultimate bearing capacity of the concrete-filled steel tube member according to the corrected compressive strength value, so as to realize the optimal design of the concrete-filled steel tube member.

[0060] By introducing the load eccentricity effect to correct the axial compression constitutive model of the existing concrete-filled steel tube members, the influence of eccentric load on the binding force of the concrete-filled steel tube members can be considered more comprehensively, and it can be further used to correct the design value of the compressive strength and the design value of the ultimate bearing capacity in the existing codes, so as to more accurately predict the mechanical properties of the concrete-filled steel tube members under eccentric load and realize the optimal design of the concrete-filled steel tube members in super high-rise buildings.

[0061] First, execute S1. According to the design drawings, use finite element analysis software to establish a finite element model of the eccentrically compressed concrete-filled steel tube member in a super high-rise building, and reasonably set the boundary conditions and load conditions. The finite element model includes two parts: the steel tube and the core concrete.

[0062] Then execute S2. Based on the finite element model, calculate the corrected binding force of the steel tube on the core concrete. Specifically, in this embodiment, when considering the influence of eccentric compression of the concrete-filled steel tube member, it is corrected by analyzing the cross-section stress change. The binding force is related to the axial strain of the core concrete, and further related to the axial stress. When the stress of the core concrete is zero, the binding force is zero. Within a certain range, the greater the stress, the greater the binding force. The following assumptions can be obtained:

[0063] 1) The binding force is zero when the stress is zero;

[0064] 2) The binding force of the core concrete changes linearly along the eccentricity direction within the cross-section range and remains constant in the direction perpendicular to the eccentricity.

[0065] As Figure 2 and Figure 3 shown, due to the action of eccentric load, there are two typical stress distribution situations of the confined concrete, namely the whole cross-section is compressed or part of it is compressed. The judgment criterion is whether there is a zero compressive stress position far from the eccentric side in the confined concrete. Therefore, when the axial stress generated by the concrete bending cancels out the axial stress generated by compression, the following formula is satisfied:

[0066]

[0067] The eccentric pressure borne by the core concrete can be decomposed into a resultant force N0 and a resultant moment M0 acting on the center of the cross-section; where A is the cross-sectional area; E c represents the initial elastic modulus of the core concrete; I is the moment of inertia; Dc is the diameter of the pressure-bearing concrete. According to whether the eccentricity e is greater than or less than D c / 8, there are the following two cases:

[0068] In the first case, e ≤ D c / 8, the entire cross-section bears compressive stress, as Figure 2 shown. At this time, the distribution of the sectional binding force presents a gradient effect on the entire cross-section. Then, the maximum binding force f l,max = f l , f l is the binding force of the steel pipe on the core concrete before correction. Then, according to assumption 2, the minimum binding force is calculated by interpolation as follows:

[0069]

[0070] In order to evaluate the degree of restraint of the steel pipe on the core concrete and provide convenience for subsequent applications, an integral calculation method for the corrected binding force f lg in the cross-section is proposed. This parameter will reflect the restrained level of the core concrete.

[0071]

[0072] In the formula, Z is the distribution function of the binding force on the cross-section, and C represents the corresponding cross-section. By solving the integral in the equation, the corrected binding force can be obtained.

[0073] In the second case, e > D c / 8, the minimum value f l,min of the binding force is zero. As Figure 3 shown, only the binding force in the compression area is considered on the cross-section at this time. Then, by solving the integral equation, the corrected binding force f lg in the cross-section can still be obtained, specifically as follows:

[0074] f l,max = f l

[0075]

[0076] The expressions for calculating the parameters V e and P e are as follows:

[0077]

[0078]

[0079] To sum up, the expression for the corrected binding force f lg can be expressed as follows:

[0080]

[0081] The relationship between the modified binding force and eccentricity is as Figure 4 shown. As the eccentricity increases, the modified binding force decreases rapidly. The relationship between the stress-strain curve of the core concrete and the modified binding force is as Figure 5 shown. With the change of the modified binding force, the change of the stress-strain curve of the core concrete can also be seen. When the binding force is stronger, the strength of the core concrete is higher.

[0082] Then, execute S3. Substitute the calculated modified binding force into the axial compression constitutive model of the concrete-filled steel tube member. Introduce a gradient effect analysis model in the design of the concrete-filled steel tube member, consider the uneven stress caused by eccentric load, and establish a concrete-filled steel tube analysis model considering the gradient effect caused by eccentric load.

[0083] It should be noted that in this embodiment, the axial compression constitutive model of the concrete-filled steel tube member is the Hu model. The source of this Hu model is from the existing literature (Hu, H.T., Huang C.S., and Wu Y.M. (2003). “Nonlinear analysis of axially loaded concrete-filled tube columns with confinement effect” J. Struct. Eng. 129(10), 1322 - 1329.). The Hu model provides a calculation formula for confined concrete based on the diameter-thickness ratio of the steel tube, and is verified by experimental data and nonlinear finite element software. It is a constitutive model suitable for axial compression.

[0084] The Hu model describes the situation of concrete-filled steel tube columns under axial compression. However, in practical applications, concrete-filled steel tube columns often experience complex load conditions, especially eccentric compression. Therefore, in this embodiment, the model is appropriately modified to solve the situation of eccentric compression. Figure 6 It is a comparison diagram of the confined concrete curve and the unconfined concrete curve under general conditions. The axial bearing capacity of the confined concrete is significantly improved, and the ductility is significantly enhanced.

[0085] In this embodiment, the concrete-filled steel tube analysis model is as follows:

[0086]

[0087] f c ' c = f c '+ 4.1f 1g ,

[0088]

[0089] wherein, σ and ε are the stress and strain that confine the core concrete; f′ c and ε′ c represent the uniaxial compressive strength and the corresponding strain; f′ cc and ε′ cc represent the compressive strength and the corresponding strain of the core concrete strengthened by the confinement force; E c represents the initial elastic modulus of the core concrete; k3 is a material degradation parameter used to represent the strength degradation of the material; f lg is the modified confinement force; f l is the confinement force of the steel pipe on the core concrete before modification;

[0090] wherein, the f l and the k3 are calculated by the following formulas:

[0091]

[0092] wherein, D is the diameter of the steel pipe; t is the thickness of the steel pipe; f y is the yield strength of the steel pipe.

[0093] Finally, execute S4, call the concrete-filled steel tube analysis model to correct the design value of the compressive strength of the core concrete to obtain the corrected compressive strength value, and then calculate the ultimate bearing capacity of the concrete-filled steel tube member according to the corrected compressive strength value, so as to realize the optimal design of the concrete-filled steel tube member.

[0094] In this embodiment, the formula for calling the concrete-filled steel tube analysis model to correct the design value of the compressive strength of the core concrete is as follows:

[0095] f cx = k1f c ;

[0096]

[0097] wherein, f cx is the corrected compressive strength; f c is the design value of the compressive strength; f′ cc1 is the concrete compressive strength when the eccentricity is 0; f′ cc2 is the concrete compressive strength when the eccentricity is e; k1 is a correction coefficient.

[0098] The formula for calculating the ultimate bearing capacity of the concrete-filled steel tube member according to the corrected compressive strength value is as follows:

[0099]

[0100] And in any case, the following formula conditions shall be satisfied:

[0101]

[0102] In the formula, N u is the ultimate bearing capacity of the concrete-filled steel tube member; θ is the confinement coefficient of the concrete-filled steel tube member; α is the coefficient related to the strength grade of the core concrete; A c is the cross-sectional area of the core concrete; f c is the design value of the compressive strength of the core concrete; A s is the cross-sectional area of the steel tube; f is the design value of the compressive strength of the steel tube; is the bearing capacity reduction coefficient considering the influence of eccentricity; is the bearing capacity reduction coefficient considering the influence of slenderness ratio; is the value that should be considered as an axially compressed column.

[0103] In this embodiment, the above partial formulas and related parameters are from the "Technical Code for Concrete-Filled Steel Tube Structures GB50936-2014". Twelve groups of measured data are selected in this embodiment, and the calculation results using the original design code are compared with the calculation results using the eccentric correction design code. As shown in Table 2, Table 1 summarizes the sources of the test data and briefly describes the methods used in the comparison.

[0104]

[0105] Table 1 Supplementary data sources for code correction comparison

[0106]

[0107]

[0108] Table 2 Comparison of ultimate bearing capacity of eccentrically compressed concrete-filled steel tube

[0109] Table 2 shows the comparison between the measured values, code values and the corrected values of the present invention for the ultimate bearing capacity. It can be seen that after applying the eccentric correction of the present invention, the prediction accuracy of the ultimate bearing capacity has been greatly improved. At the same time, it can also be seen that there are still some errors in the prediction, which may be caused by factors such as the length of the test specimens.

[0110] Preferably, before the design method corrects the design value of the compressive strength of the core concrete by invoking the concrete-filled steel tube analysis model, the design method further includes:

[0111] Based on the concrete-filled steel tube analysis model, the load-displacement curve of the concrete-filled steel tube component is obtained;

[0112] The finite element model is simulated, and several concrete-filled steel tube specimens are fabricated for axial compression and eccentric compression tests. The corresponding load-displacement curves are obtained and the test results are compared.

[0113] The purpose of this step is to verify the improved concrete-filled steel tube analysis model through a large number of experimental studies and finite element simulations.

[0114] In this embodiment, an ABAQUS finite element model is established, and 8 medium slenderness ratio circular concrete-filled steel tube specimens are fabricated for axial compression and eccentric compression tests. The tests mainly consider the concrete strength and the loading eccentricity.

[0115] Figure 7 and Figure 8 For the established finite element model and the corresponding calculation results, by calculating the calculation results obtained with and without the modified model of the present invention respectively, the corresponding load-displacement curves can be obtained and compared with the test results. By Figure 8 It can be seen that the modified model of the present invention can better correct the problem of overestimating the bearing capacity of concrete-filled steel tubes under eccentric loading, thereby improving the fitting effect of the test curve.

[0116] Based on this, the embodiment of the present invention also provides an optimization design system for concrete-filled steel tube components of super high-rise buildings considering eccentric compression, which is used to implement the optimization design method for concrete-filled steel tube components of super high-rise buildings considering eccentric compression as described above, including:

[0117] The first model construction module is configured to establish a finite element model of the concrete-filled steel tube component under eccentric compression in a super high-rise building by using finite element analysis software according to the design drawings, and reasonably set the boundary conditions and load conditions. The finite element model includes two parts: the steel tube and the core concrete;

[0118] The calculation module is configured to calculate the modified binding force of the steel tube on the core concrete based on the finite element model;

[0119] The second model construction module is configured to substitute the calculated modified binding force into the axial compression constitutive model of the concrete-filled steel tube component, introduce a gradient effect analysis model in the design of the concrete-filled steel tube component, consider the non-uniform stress caused by the eccentric load, and establish a concrete-filled steel tube analysis model considering the gradient effect caused by the eccentric load;

[0120] A correction module is configured to call the concrete-filled steel tube analysis model to correct the design value of the compressive strength of the core concrete to obtain a corrected compressive strength value, and then calculate the ultimate bearing capacity of the concrete-filled steel tube member according to the corrected compressive strength value, so as to realize the optimal design of the concrete-filled steel tube member.

[0121] Preferably, the binding force of the core concrete varies linearly along the eccentricity direction within the cross-section range and remains constant in the direction perpendicular to the eccentricity direction.

[0122] Preferably, the design system further includes a simulation module, and the simulation module is configured to:

[0123] Obtain the load-displacement curve of the concrete-filled steel tube member based on the concrete-filled steel tube analysis model;

[0124] Perform simulation on the finite element model, fabricate a number of concrete-filled steel tube specimens for axial compression and eccentric compression tests, obtain the corresponding load-displacement curves and compare the test results.

[0125] Based on the same inventive concept, an embodiment of the present invention further provides a readable storage medium, on which a computer program is stored, and when the computer program is executed, it can implement the above-mentioned optimization design method for concrete-filled steel tube members of super high-rise buildings considering eccentric compression.

[0126] A readable storage medium can be a tangible device that can hold and store instructions used by an instruction execution device. For example, it can be, but is not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the above. More specific examples (a non-exhaustive list) of the readable storage medium include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disc (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punched card or raised structures in grooves storing instructions thereon, and any suitable combination of the above. The computer programs described herein can be downloaded from the readable storage medium to various computing / processing devices, or downloaded to an external computer or external storage device through a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter or network interface in each computing / processing device receives the computer program from the network and forwards the computer program for storage in the readable storage medium in each computing / processing device. The computer program for performing the operations of the present invention can be running instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages. The programming languages include object-oriented programming languages - such as Smalltalk, C++, etc., and conventional procedural programming languages - such as the "C" language or similar programming languages. The computer program can be executed entirely on the user's computer, partially on the user's computer, executed as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computer (e.g., by using an Internet service provider to connect through the Internet). In some embodiments, by using the status information of the computer program to personalize an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), the electronic circuit can execute computer-readable program instructions to implement various aspects of the present invention.

[0127] Aspects of the present invention are described herein with reference to the flowcharts and / or block diagrams of methods, systems, and computer program products according to embodiments of the present invention. It should be understood that each block of the flowcharts and / or block diagrams, and combinations of blocks in the flowcharts and / or block diagrams, can be implemented by computer programs. These computer programs can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, thereby producing a machine such that when these programs are executed by the processor of the computer or other programmable data processing device, a device is produced that implements the functions / actions specified in one or more blocks of the flowcharts and / or block diagrams. These computer programs can also be stored in a readable storage medium, and these computer programs cause a computer, a programmable data processing device, and / or other devices to work in a specific manner. Thus, the readable storage medium storing the computer programs includes a manufactured article that includes instructions for implementing various aspects of the functions / actions specified in one or more blocks of the flowcharts and / or block diagrams.

[0128] The computer programs can also be loaded onto a computer, other programmable data processing device, or other device, such that a series of operation steps are executed on the computer, other programmable data processing device, or other device to produce a computer-implemented process, so that the computer programs executed on the computer, other programmable data processing device, or other device implement the functions / actions specified in one or more blocks of the flowcharts and / or block diagrams.

[0129] In summary, the embodiments of the present invention provide an optimized design method for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression. By introducing the load eccentricity effect to correct the axial compression constitutive model of existing concrete-filled steel tubular members, the influence of eccentric loads on the binding force of concrete-filled steel tubular members can be considered more comprehensively, and further used to correct the compressive strength design value and ultimate bearing capacity design value in the existing specifications, so as to more accurately predict the mechanical properties of the concrete-filled steel tubular members under eccentric loads, realize the optimized design of concrete-filled steel tubular members in super high-rise buildings, and improve the bearing capacity and long-term performance stability of concrete-filled steel tubular columns under complex stress states.

[0130] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention in any way. Any changes and modifications made by those of ordinary skill in the art of the present invention based on the above disclosure belong to the protection scope of the present invention. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations are within the scope of the present invention and its equivalent technologies, the present invention also intends to include these modifications and variations.

Claims

1. An optimization design method for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression, characterized in that, Including: According to the design drawings, a finite element model of a concrete-filled steel tubular member under eccentric compression in a super high-rise building is established using finite element analysis software, and the boundary conditions and load conditions are reasonably set. The finite element model includes two parts: the steel tube and the core concrete; Based on the finite element model, calculate the modified binding force of the steel tube on the core concrete; Substitute the calculated modified binding force into the axial compression constitutive model of the concrete-filled steel tubular member, introduce a gradient effect analysis model in the design of the concrete-filled steel tubular member, consider the uneven stress caused by the eccentric load, and establish a concrete-filled steel tubular analysis model considering the gradient effect caused by the eccentric load; Call the concrete-filled steel tubular analysis model to correct the design value of the compressive strength of the core concrete to obtain a corrected compressive strength value, and then calculate the ultimate bearing capacity of the concrete-filled steel tubular member according to the corrected compressive strength value, so as to realize the optimized design of the concrete-filled steel tubular member.

2. The optimized design method for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression according to claim 1, characterized in that, The binding force of the core concrete varies linearly along the eccentricity direction within the cross-section range and remains constant in the direction perpendicular to the eccentricity.

3. The optimized design method for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression according to claim 1, characterized in that, The formula for calculating the modified binding force of the steel tube on the core concrete based on the finite element model is as follows: Where f lg is the corrected binding force; D e is the diameter of the core concrete; f l is the binding force of the steel pipe on the core concrete before correction; e is the eccentricity; V e and P e are calculation parameters.

4. The optimized design method for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression according to claim 1, wherein, The concrete-filled steel tubular analysis model is as follows: wherein, σ and ε are the stress and strain that confine the core concrete; f′ c and ε′ c represent the uniaxial compressive strength and the corresponding strain; f′ cc and ε′ cc represent the compressive strength of the core concrete strengthened by the confinement force and the corresponding strain; E c represents the initial elastic modulus of the core concrete; k3 is a material degradation parameter used to represent the strength degradation of the material; f lg is the corrected confinement force; f l is the confinement force of the steel pipe on the core concrete before correction; Among them, the f l and the calculation formulas of the k3 are as follows: Where D is the diameter of the steel pipe; t is the thickness of the steel pipe; and f y is the yield strength of the steel pipe.

5. The optimized design method for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression according to claim 1, characterized in that, The formula for correcting the design value of the compressive strength of the core concrete by calling the concrete-filled steel tubular analysis model is as follows: f cx = k1f c ; where f cx is the corrected compressive strength; f c is the design value of the compressive strength of the core concrete; f′ cc1 is the concrete compressive strength when the eccentricity is 0; f′ cc2 is the concrete compressive strength when the eccentricity is e; k1 is the correction factor; The formula for calculating the ultimate bearing capacity of the concrete-filled steel tubular member according to the corrected compressive strength value is as follows: And in any case, the following formula condition should be satisfied: Where N u is the ultimate bearing capacity of the concrete-filled steel tube member; θ is the hoop coefficient of the concrete-filled steel tube member; α is the coefficient related to the strength grade of the core concrete; A c is the cross-sectional area of the core concrete; f c is the design value of the compressive strength of the core concrete; A s is the cross-sectional area of the steel tube; f is the design value of the compressive strength of the steel tube; is the bearing capacity reduction coefficient considering the influence of eccentricity; is the bearing capacity reduction coefficient considering the influence of slenderness ratio; should be considered as that of an axially compressed column value.

6. The optimized design method for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression according to claim 1, characterized in that, Before calling the concrete-filled steel tubular analysis model to correct the design value of the compressive strength of the core concrete, the design method further includes: Based on the concrete-filled steel tubular analysis model, obtain the load-displacement curve of the concrete-filled steel tubular member; Conduct a simulation of the finite element model, fabricate several concrete-filled steel tubular specimens for axial compression and eccentric compression tests, obtain the corresponding load-displacement curves and compare the test results.

7. An optimized design system for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression is used to implement the optimized design method for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression according to any one of claims 1-6, characterized in that Including: A first model construction module configured to establish a finite element model of a concrete-filled steel tubular member under eccentric compression in a super high-rise building using finite element analysis software according to the design drawings, and reasonably set the boundary conditions and load conditions. The finite element model includes two parts: the steel tube and the core concrete; A calculation module configured to calculate the modified binding force of the steel tube on the core concrete based on the finite element model; A second model construction module configured to substitute the calculated modified binding force into the axial compression constitutive model of the concrete-filled steel tubular member, introduce a gradient effect analysis model in the design of the concrete-filled steel tubular member, consider the uneven stress caused by the eccentric load, and establish a concrete-filled steel tubular analysis model considering the gradient effect caused by the eccentric load; A correction module configured to call the concrete-filled steel tubular analysis model to correct the design value of the compressive strength of the core concrete to obtain a corrected compressive strength value, and then calculate the ultimate bearing capacity of the concrete-filled steel tubular member according to the corrected compressive strength value, so as to realize the optimized design of the concrete-filled steel tubular member.

8. The optimized design system for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression according to claim 7, characterized in that, The binding force of the core concrete varies linearly along the eccentricity direction within the cross-section range and remains constant in the direction perpendicular to the eccentricity direction.

9. The optimized design system for concrete-filled steel tubular members of super high-rise buildings considering eccentric compression according to claim 7, characterized in that, The design system further includes a simulation module configured to: Obtain the load-displacement curve of the concrete-filled steel tube member based on the concrete-filled steel tube analysis model; Perform simulation on the finite element model, fabricate a number of concrete-filled steel tube specimens for axial compression and eccentric compression tests, obtain the corresponding load-displacement curves and compare the test results.

10. A readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed, it can implement the optimized design method for concrete-filled steel tube members of super high-rise buildings considering eccentric compression according to any one of claims 1-6.

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