Method for calculating compression bearing capacity of GFRP pipe constrained UHPC column by considering fiber winding angle

Abstract

The invention relates to the technical field of building material bearing capacity calculation, and discloses a GFRP pipe constrained UHPC column compression bearing capacity calculation method considering a fiber winding angle, and the method comprises the steps: building a mapping model of the fiber winding angle and a circumferential tensile elastic modulus; determining the circumferential constraint stress of the GFRP pipe based on the material parameters and the mapping model; establishing an ultimate strength-ultimate strain model of the GFRP pipe constrained core UHPC column according to the circumferential constraint stress and the constraint strength influence coefficient; determining the axial compression strength of the core UHPC column restrained by the GFRP pipe; and determining the ultimate bearing capacity of the GFRP pipe constrained core UHPC column under eccentric compression based on the ultimate bearing capacity model of the eccentric compression column and the axial compression strength. According to the method, the compression bearing capacity of the GFRP pipe constrained UHPC column at different fiber winding angles can be predicted, and the calculation accuracy and reliability are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of building material bearing capacity calculation, and in particular to a method for calculating the compressive bearing capacity of a UHPC column constrained by a GFRP tube taking into account a fiber winding angle. Background Art

[0002] With the increasing demand for high-performance materials in civil engineering, ultra-high-performance concrete (UHPC) is widely used in column structures due to its exceptional strength and durability. However, the brittle nature of UHPC makes it susceptible to sudden failure under compression, necessitating external restraint to improve its ductility and bearing capacity. Glass fiber reinforced plastic (GFRP) pipes, due to their lightweight, high strength, and corrosion resistance, are an ideal choice for restraining UHPC columns. However, existing methods for calculating the bearing capacity of UHPC columns restrained by GFRP pipes have the following limitations:

[0003] The influence of fiber winding angle is not fully considered: Traditional models often assume that GFRP tubes are isotropic materials, or are based on simplified assumptions based on the hoop elastic modulus, ignoring the significant impact of fiber winding angle on hoop stiffness and constraint effectiveness, resulting in large deviations between the calculated results and the actual load-bearing performance.

[0004] Lack of accurate strength-strain models: The strength-strain relationship of UHPC under strong constraints exhibits nonlinear characteristics. Existing models mostly use simplified models of ordinary concrete or FRP-confined concrete, which fail to accurately reflect the mechanical behavior of UHPC under GFRP tube confinement. The error is particularly prominent under eccentric compression conditions.

[0005] Insufficient assessment of eccentric compressive bearing capacity: In actual engineering, columns often bear eccentric loads. Existing methods are mostly based on the axial compression assumption, and no ultimate bearing capacity model suitable for eccentric compression has been established, making it difficult to meet design requirements under complex working conditions.

[0006] Therefore, a refined calculation method that comprehensively considers the GFRP tube fiber winding angle, material parameters and eccentricity effect is urgently needed to accurately evaluate the compressive bearing capacity of the constrained UHPC column and promote the application of this composite structure in engineering. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for calculating the compressive bearing capacity of UHPC columns constrained by GFRP tubes taking into account the fiber winding angle, in order to solve the above problems.

[0008] The present invention provides a method for calculating the compressive bearing capacity of a GFRP tube-constrained UHPC column taking into account the fiber winding angle, comprising:

[0009] Obtain the material parameters of the GFRP tube and core UHPC column;

[0010] A mapping model between the fiber winding angle and the hoop tensile elastic modulus of GFRP tubes was established;

[0011] determining the hoop restraint stress of the GFRP pipe based on the material parameters and the mapping model;

[0012] Based on the strength-strain characteristics, the constraint strength influence coefficient is obtained, and the ultimate strength-ultimate strain model of the GFRP tube-constrained core UHPC column is established according to the hoop constraint stress and the constraint strength influence coefficient;

[0013] Determine the axial compressive strength of the GFRP tube-constrained core UHPC column based on the hoop confinement stress and ultimate strength-ultimate strain model;

[0014] An ultimate bearing capacity model of eccentrically compressed columns was established, and based on the ultimate bearing capacity model and the axial compressive strength, the ultimate bearing capacity of the GFRP tube-constrained core UHPC column under eccentric compression was determined.

[0015] Preferably, the material parameters include the thickness of the GFRP tube, the fiber winding angle of the GFRP tube, and the diameter of the core UHPC column.

[0016] Preferably, establishing a mapping model between the GFRP tube fiber winding angle and the hoop tensile elastic modulus includes:

[0017] Acquiring test data of a fiber winding angle and a hoop tensile elastic modulus of a GFRP tube, wherein the test data includes the fiber winding angle and the corresponding hoop tensile elastic modulus;

[0018] Fitting the fiber winding angle and the hoop tensile elastic modulus to obtain a mapping model of the fiber winding angle and the hoop tensile elastic modulus of the GFRP tube;

[0019] The expression of the mapping model is:

[0020] E GFRP =58.79ln(x)+22.41 0.79≤x≤1.57;

[0021] Among them, E GFRP represents the hoop tensile elastic modulus of the GFRP tube, x represents the fiber winding angle, and the fiber winding angle is expressed in radians.

[0022] Preferably, determining the hoop restraint stress of the GFRP pipe based on the material parameters and the mapping model includes:

[0023] The hoop tensile elastic modulus E of the GFRP tube is determined according to the fiber winding angle of the GFRP tube and the mapping model. GFRP ;

[0024] Based on the hoop tensile elastic modulus E of the GFRP pipe GFRP The hoop restraint stress f of the GFRP tube is determined by the thickness of the GFRP tube and the diameter of the core UHPC column. l，a ;

[0025] The hoop restraint stress f of the GFRP pipe l，a Calculate according to the following formula:

[0026]

[0027] Among them, f l，a represents the hoop restraint stress of the GFRP pipe, E GFRP represents the hoop tensile elastic modulus of the GFRP pipe, ε h，rup represents the circumferential ultimate strain of the GFRP pipe, t f represents the thickness of the GFRP tube, and D represents the diameter of the core UHPC column.

[0028] Preferably, the constraint strength influence coefficients are k1=3.91 and k2=22.69.

[0029] Preferably, an ultimate strength-ultimate strain model of a GFRP tube-constrained core UHPC column is established based on the hoop constraint stress and the constraint strength influence coefficient, comprising:

[0030] The strength-strain model of confined concrete is preset;

[0031] Substituting the constraint strength influence coefficient into the constraint concrete strength-strain model to obtain the ultimate strength-ultimate strain model of the GFRP tube constrained core UHPC column;

[0032] The confined concrete strength-strain model is:

[0033]

[0034] The ultimate strength-ultimate strain model of the GFRP tube-constrained core UHPC column is:

[0035]

[0036] Among them, f co represents the ultimate compressive strength of unconfined concrete, f cu represents the ultimate compressive strength of the restrained specimen, ε cu represents the constrained ultimate axial strain, ε co represents the unconstrained ultimate axial strain, ε h,rup represents the circumferential ultimate strain of the GFRP pipe, t frp represents the thickness of the GFRP tube, D represents the diameter of the core UHPC column, and E GFRPrepresents the hoop tensile elastic modulus of the GFRP pipe, f l，a represents the hoop restraint stress of the GFRP tube, E1 represents the elastic modulus of the core UHPC column, E1=3840f co 1 / 2 .

[0037] Preferably, determining the axial compressive strength of the GFRP tube-constrained core UHPC column according to the hoop confinement stress and ultimate strength-ultimate strain model comprises:

[0038] The hoop restraint stress is input into the ultimate strength-ultimate strain model to determine the ultimate compressive strength f of the GFRP tube-constrained core UHPC column. cu ;

[0039] Determine the area A of the core UHPC column co , according to the ultimate compressive strength f of the GFRP tube-constrained core UHPC column cu and the area A of the core UHPC column co Determine the axial compressive strength N of the GFRP tube-confined core UHPC column p ;

[0040] Axial compressive strength N of UHPC column with GFRP tube confined core p The calculation formula is N p =f cu A co .

[0041] Preferably, establishing an ultimate bearing capacity model of an eccentrically compressed column includes:

[0042] The eccentric compressive bearing capacity foundation model is preset;

[0043] The aspect ratio and eccentricity are analyzed, and based on the analysis results, the basic model of eccentrically compressed bearing capacity is transformed to obtain the ultimate bearing capacity model of eccentrically compressed columns;

[0044] The expression of the ultimate bearing capacity model of the eccentrically compressed column is:

[0045]

[0046] Among them, N e represents the ultimate bearing capacity of the eccentrically compressed column, represents the eccentricity influence coefficient, e / R represents the eccentricity ratio, A co Represents the area of ​​the core UHPC column.

[0047] Preferably, the expression of the eccentric compressive bearing capacity foundation model is:

[0048]

[0049] Among them, N e represents the ultimate bearing capacity of eccentrically compressed columns; represents the aspect ratio influence coefficient, represents the eccentricity influence coefficient, c = -0.6611, e / R represents the eccentricity, N p Indicates the axial compressive bearing capacity.

[0050] Preferably, determining the ultimate bearing capacity of the GFRP tube-constrained core UHPC column under eccentric compression based on the ultimate bearing capacity model of the eccentrically compressed column and the axial compressive strength includes:

[0051] The axial compressive strength N of the GFRP tube-constrained core UHPC column p The ultimate bearing capacity of the UHPC column with GFRP tube confined core under eccentric compression was obtained by inputting it into the expression of the ultimate bearing capacity model of the eccentrically compressed column.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] By establishing a mapping model between the GFRP tube fiber winding angle and the hoop tensile elastic modulus, the mechanism by which angle changes affect the hoop constraint stiffness is quantified, correcting the errors in the traditional isotropy assumption and significantly improving the accuracy of constraint stress calculations. Based on the constraint strength influence coefficient and combining the stress-strain characteristics of UHPC, a specialized model for GFRP tube-constrained UHPC columns is proposed. This model truly reflects the enhancement of the strength and ductility of the core concrete through the confinement effect, making it particularly suitable for nonlinear response analysis of high-strength UHPC materials.

[0054] This invention not only clarifies the calculation method for axial compressive strength but also designs a model for the ultimate bearing capacity of eccentrically compressed columns. By coupling the hoop constraint stress with the eccentricity parameter, this method accurately predicts the bearing capacity under complex loads, filling a gap in existing technology for eccentric compression analysis. This method provides a theoretical basis for the design of GFRP tube-UHPC column structures, optimizing the fiber winding angle and layer configuration, balancing material usage with load-bearing performance, and reducing trial-and-error costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0056] Figure 1 The figure is a flow chart of a method for calculating the compressive bearing capacity of a UHPC column constrained by a GFRP tube taking into account the fiber winding angle of the present invention. DETAILED DESCRIPTION

[0057] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0058] like Figure 1 As shown, the present invention provides a method for calculating the compressive bearing capacity of GFRP tube-constrained UHPC columns, taking into account the fiber winding angle. This method can more accurately predict the compressive bearing capacity of GFRP tube-constrained UHPC columns at different fiber winding angles, improving the accuracy and reliability of the calculation. This method considers the influence of fiber winding angle on the mechanical properties of GFRP tubes. By establishing a mapping model and a stress-strain model, it can comprehensively reflect the mechanical characteristics of GFRP tube-constrained core UHPC columns.

[0059] The present invention comprises the following steps:

[0060] S100: Obtain material parameters of the GFRP tube and the core UHPC column.

[0061] In this embodiment, the material parameters include the thickness of the GFRP tube, the fiber winding angle of the GFRP tube, and the diameter of the core UHPC column.

[0062] S200: Establish a mapping model between the fiber winding angle of the GFRP tube and the hoop tensile elastic modulus.

[0063] In some embodiments of the present application, a mapping model between the fiber winding angle of the GFRP tube and the hoop tensile elastic modulus is established, including: obtaining test data of the fiber winding angle and the hoop tensile elastic modulus of the GFRP tube, the test data including the fiber winding angle and the corresponding hoop tensile elastic modulus; fitting the fiber winding angle and the hoop tensile elastic modulus to obtain a mapping model between the fiber winding angle and the hoop tensile elastic modulus of the GFRP tube.

[0064] The expression of the mapping model is:

[0065] E GFRP =58.79ln(x)+22.41 0.79≤x≤1.57;

[0066] Among them, E GFRP represents the hoop tensile elastic modulus of the GFRP tube, and x represents the fiber winding angle, expressed in radians.

[0067] As can be seen, constructing such a mapping model allows for more accurate prediction of the hoop tensile elastic modulus of GFRP tubes at different fiber winding angles, which is crucial for accurately evaluating the compressive performance of GFRP tube-constrained UHPC columns. Engineers and designers can use this mapping model to quickly estimate the mechanical properties of GFRP tubes during the preliminary design phase, avoiding tedious experimental testing and saving time and costs. Furthermore, the application of this mapping model makes parameter adjustments in structural design more flexible and efficient, helping to further optimize structural performance and enhance its load-bearing capacity and safety.

[0068] S300: Determine the hoop restraint stress of the GFRP pipe based on the material parameters and the mapping model.

[0069] In some embodiments of the present application, determining the hoop constraint stress of the GFRP tube based on the material parameters and the mapping model includes: determining the hoop tensile elastic modulus E of the GFRP tube according to the fiber winding angle of the GFRP tube and the mapping model. GFRP Based on the hoop tensile elastic modulus E of the GFRP tube GFRP The hoop restraint stress f of the GFRP tube is determined by the thickness of the GFRP tube and the diameter of the core UHPC column. l，a .

[0070] The hoop restraint stress f of the GFRP pipe l，a Calculate according to the following formula:

[0071]

[0072] Among them, f l，a represents the hoop restraint stress of the GFRP pipe, E GFRP represents the hoop tensile elastic modulus of the GFRP pipe, ε h，rup represents the circumferential ultimate strain of the GFRP pipe, t f represents the thickness of the GFRP tube, and D represents the diameter of the core UHPC column.

[0073] It can be understood that by combining material parameters and the mapping model, the hoop confinement stress of the GFRP tube can be accurately calculated, which is crucial for evaluating the overall compressive performance of GFRP tube-constrained UHPC columns. During the structural design process, engineers and designers can use this calculation method to quickly obtain the hoop confinement stress value of the GFRP tube, thereby more accurately assessing the load-bearing capacity and safety of the structure. Furthermore, the application of this method makes material selection and parameter adjustment in structural design more scientific and reasonable, helping to further optimize structural performance and improve the cost-effectiveness and durability of the structure.

[0074] S400: Based on the strength-strain characteristics, a constraint strength influence coefficient is obtained, and an ultimate strength-ultimate strain model of the GFRP tube-constrained core UHPC column is established according to the hoop constraint stress and the constraint strength influence coefficient.

[0075] In some embodiments of the present application, the constraint strength influence coefficients are k1=3.91 and k2=22.69.

[0076] In some embodiments of the present application, an ultimate strength-ultimate strain model of a GFRP tube-constrained core UHPC column is established based on the hoop confinement stress and the confinement strength influence coefficient, including:

[0077] A constrained concrete strength-strain model is preset; the constraint strength influence coefficient is substituted into the constrained concrete strength-strain model to obtain an ultimate strength-ultimate strain model of a GFRP tube constrained core UHPC column.

[0078] The confined concrete strength-strain model is:

[0079]

[0080] The ultimate strength-ultimate strain model of the GFRP tube-constrained core UHPC column is:

[0081]

[0082] Among them, f co represents the ultimate compressive strength of unconfined concrete, f cu represents the ultimate compressive strength of the restrained specimen, ε cu represents the constrained ultimate axial strain, ε co represents the unconstrained ultimate axial strain, ε h,rup represents the circumferential ultimate strain of the GFRP pipe, t frp represents the thickness of the GFRP tube, D represents the diameter of the core UHPC column, and E GFRP represents the hoop tensile elastic modulus of the GFRP pipe, f l，a represents the hoop restraint stress of the GFRP tube, E1 represents the elastic modulus of the core UHPC column, E1=3840f co 1 / 2 .

[0083] In this embodiment, Richart et al. proposed a confined concrete strength-strain model, and the Richart model was modified to propose that the confined strength influence coefficients are k1=3.91 and k2=22.69.

[0084] It can be understood that by introducing the constraint strength influence coefficients k1 and k2, combined with a pre-defined constrained concrete strength-strain model, the present invention is able to establish an ultimate strength-ultimate strain model applicable to GFRP tube-constrained core UHPC columns. This model not only considers the impact of the GFRP tube's hoop constraint stress on the compressive performance of the core UHPC column, but also comprehensively considers multiple material and structural parameters, making the model more realistic for actual engineering conditions. When using this model for calculations, engineers and designers can quickly obtain the stress-strain relationship of the GFRP tube-constrained core UHPC column, which is of great significance for structural stress analysis and design optimization.

[0085] S500: Determine the axial compressive strength of the GFRP tube-constrained core UHPC column according to the hoop confinement stress and ultimate strength-ultimate strain model.

[0086] In some embodiments of the present application, the axial compressive strength of the GFRP tube-constrained core UHPC column is determined according to the hoop constraint stress and the ultimate strength-ultimate strain model, including: inputting the hoop constraint stress into the ultimate strength-ultimate strain model to determine the ultimate compressive strength f of the GFRP tube-constrained core UHPC column. cu ; Determine the area A of the core UHPC column co , according to the ultimate compressive strength f of the GFRP tube-constrained core UHPC column cu and the area A of the core UHPC column co Determine the axial compressive strength N of the GFRP tube-confined core UHPC column p ; Axial compressive strength of GFRP tube-constrained core UHPC column N p The calculation formula is N p =f cu A co .

[0087] As can be seen, by combining the hoop confinement stress with the established ultimate strength-ultimate strain model, the present invention accurately determines the axial compressive strength of GFRP tube-constrained core UHPC columns. This method not only improves calculation accuracy but also enables rapid assessment of the compressive performance of GFRP tube-constrained core UHPC columns. When determining the axial compressive strength, the present invention considers the contribution of the GFRP tube's hoop confinement effect to the core UHPC column's strength improvement, which helps to more fully understand the interaction mechanism between the GFRP tube and the core UHPC column.

[0088] S600: Establish an ultimate bearing capacity model for an eccentrically compressed column, and determine the ultimate bearing capacity of a GFRP tube-constrained core UHPC column under eccentric compression based on the ultimate bearing capacity model for the eccentrically compressed column and the axial compressive strength.

[0089] In some embodiments of the present application, an ultimate bearing capacity model of an eccentrically compressed column is established, including: presetting an eccentrically compressed bearing capacity basic model; analyzing the aspect ratio and eccentricity, and transforming the eccentrically compressed bearing capacity basic model based on the analysis results to obtain an ultimate bearing capacity model of an eccentrically compressed column.

[0090] The expression of the ultimate bearing capacity model of the eccentrically compressed column is:

[0091]

[0092] Among them, N e represents the ultimate bearing capacity of the eccentrically compressed column, represents the eccentricity influence coefficient, e / R represents the eccentricity ratio, A co Represents the area of ​​the core UHPC column.

[0093] In some embodiments of the present application, the expression of the eccentric compressive bearing capacity foundation model is:

[0094]

[0095] Among them, N e represents the ultimate bearing capacity of eccentrically compressed columns; represents the aspect ratio influence coefficient, represents the eccentricity influence coefficient, c = -0.6611, e / R represents the eccentricity, N p Indicates the axial compressive bearing capacity.

[0096] In some embodiments of the present application, the ultimate bearing capacity of the GFRP tube-constrained core UHPC column under eccentric compression is determined based on the ultimate bearing capacity model of the eccentrically compressed column and the axial compressive strength, including: p The ultimate bearing capacity of the UHPC column with GFRP tube confined core under eccentric compression was obtained by inputting it into the expression of the ultimate bearing capacity model of the eccentrically compressed column.

[0097] It is understood that by introducing a basic model for eccentric compressive bearing capacity and combining it with an analysis of aspect ratio and eccentricity, the present invention is able to accurately establish a model for the ultimate bearing capacity of eccentrically compressed columns for eccentric compression conditions. This model not only considers the impact of eccentricity on bearing capacity but also transforms the basic model to make it more applicable to actual conditions. When determining the ultimate bearing capacity of eccentrically compressed columns, the present invention comprehensively considers multiple factors, including eccentricity and the area of ​​the core UHPC column, which facilitates a more comprehensive assessment of the bearing performance of eccentrically compressed columns.

[0098] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or a combination of software and hardware embodiments. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0099] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0100] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0101] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A method for calculating the compressive bearing capacity of GFRP tube-constrained UHPC columns considering the fiber winding angle, characterized in that: include: Obtain the material parameters of the GFRP tube and core UHPC column; A mapping model between the fiber winding angle and the hoop tensile elastic modulus of GFRP tubes was established; determining the hoop restraint stress of the GFRP pipe based on the material parameters and the mapping model; Based on the strength-strain characteristics, the constraint strength influence coefficient is obtained, and the ultimate strength-ultimate strain model of the GFRP tube-constrained core UHPC column is established according to the hoop constraint stress and the constraint strength influence coefficient; Determine the axial compressive strength of the GFRP tube-constrained core UHPC column based on the hoop confinement stress and ultimate strength-ultimate strain model; An ultimate bearing capacity model of eccentrically compressed columns was established, and based on the ultimate bearing capacity model and the axial compressive strength, the ultimate bearing capacity of the GFRP tube-constrained core UHPC column under eccentric compression was determined.

2. The method for calculating the compressive bearing capacity of GFRP tube-constrained UHPC columns considering the fiber winding angle according to claim 1 is characterized in that: The material parameters include the thickness of the GFRP tube, the fiber winding angle of the GFRP tube, and the diameter of the core UHPC column.

3. The method for calculating the compressive bearing capacity of GFRP tube-constrained UHPC columns considering the fiber winding angle according to claim 2 is characterized in that: A mapping model between the fiber winding angle and the hoop tensile elastic modulus of GFRP tubes was established, including: Acquiring test data of a fiber winding angle and a hoop tensile elastic modulus of a GFRP tube, wherein the test data includes the fiber winding angle and the corresponding hoop tensile elastic modulus; Fitting the fiber winding angle and the hoop tensile elastic modulus to obtain a mapping model of the fiber winding angle and the hoop tensile elastic modulus of the GFRP tube; The expression of the mapping model is: E GFRP =58.79ln(x)+22.41 0.79≤x≤1.57; Among them, E GFRP represents the hoop tensile elastic modulus of the GFRP tube, x represents the fiber winding angle, and the fiber winding angle is expressed in radians.

4. The method for calculating the compressive bearing capacity of GFRP tube-constrained UHPC columns considering the fiber winding angle according to claim 3 is characterized in that: Determining the hoop restraint stress of the GFRP pipe based on the material parameters and the mapping model includes: The hoop tensile elastic modulus E of the GFRP tube is determined according to the fiber winding angle of the GFRP tube and the mapping model. GFRP ; Based on the hoop tensile elastic modulus E of the GFRP pipe GFRP The hoop restraint stress f of the GFRP tube is determined by the thickness of the GFRP tube and the diameter of the core UHPC column. l，a ; The hoop restraint stress f of the GFRP pipe l，a Calculate according to the following formula: Among them, f l，a represents the hoop restraint stress of the GFRP pipe, E GFRP represents the hoop tensile elastic modulus of the GFRP pipe, ε h，rup represents the circumferential ultimate strain of the GFRP pipe, t f represents the thickness of the GFRP tube, and D represents the diameter of the core UHPC column.

5. The method for calculating the compressive bearing capacity of GFRP tube-constrained UHPC columns considering the fiber winding angle according to claim 4 is characterized in that: The constraint strength influence coefficients are k1=3.91 and k2=22.

69.

6. The method for calculating the compressive bearing capacity of GFRP tube-constrained UHPC columns considering the fiber winding angle according to claim 5, characterized in that: Based on the hoop restraint stress and restraint strength influence coefficient, an ultimate strength-ultimate strain model of a GFRP tube-constrained core UHPC column is established, including: The strength-strain model of confined concrete is preset; Substituting the constraint strength influence coefficient into the constraint concrete strength-strain model to obtain the ultimate strength-ultimate strain model of the GFRP tube constrained core UHPC column; The confined concrete strength-strain model is: The ultimate strength-ultimate strain model of the GFRP tube-constrained core UHPC column is: Among them, f co represents the ultimate compressive strength of unconfined concrete, f cu represents the ultimate compressive strength of the restrained specimen, ε cu represents the constrained ultimate axial strain, ε co represents the unconstrained ultimate axial strain, ε h,rup represents the circumferential ultimate strain of the GFRP pipe, t frp represents the thickness of the GFRP tube, D represents the diameter of the core UHPC column, and E GFRP represents the hoop tensile elastic modulus of the GFRP pipe, f l，a represents the hoop restraint stress of the GFRP tube, E1 represents the elastic modulus of the core UHPC column, E1=3840f co 1 / 2 .

7. The method for calculating the compressive bearing capacity of GFRP tube-constrained UHPC columns considering the fiber winding angle according to claim 6, characterized in that: The axial compressive strength of the GFRP tube-constrained core UHPC column is determined based on the hoop confinement stress and ultimate strength-ultimate strain model, including: The hoop restraint stress is input into the ultimate strength-ultimate strain model to determine the ultimate compressive strength f of the GFRP tube-constrained core UHPC column. cu ; Determine the area A of the core UHPC column co , according to the ultimate compressive strength f of the GFRP tube-constrained core UHPC column cu and the area A of the core UHPC column co Determine the axial compressive strength N of the GFRP tube-confined core UHPC column p ; Axial compressive strength N of UHPC column with GFRP tube confined core p The calculation formula is N p =f cu A co .

8. The method for calculating the compressive bearing capacity of GFRP tube-constrained UHPC columns considering the fiber winding angle according to claim 7, characterized in that: Establish the ultimate bearing capacity model of eccentrically compressed columns, including: The eccentric compressive bearing capacity foundation model is preset; The aspect ratio and eccentricity are analyzed, and based on the analysis results, the basic model of eccentrically compressed bearing capacity is transformed to obtain the ultimate bearing capacity model of eccentrically compressed columns; The expression of the ultimate bearing capacity model of the eccentrically compressed column is: Among them, N e represents the ultimate bearing capacity of the eccentrically compressed column, represents the eccentricity influence coefficient, e / R represents the eccentricity ratio, A co Represents the area of ​​the core UHPC column.

9. The method for calculating the compressive bearing capacity of GFRP tube-constrained UHPC columns considering the fiber winding angle according to claim 8, characterized in that: The expression of the eccentric compressive bearing capacity foundation model is: Among them, N e represents the ultimate bearing capacity of eccentrically compressed columns; represents the aspect ratio influence coefficient, represents the eccentricity influence coefficient, c = -0.6611, e / R represents the eccentricity, N p Indicates the axial compressive bearing capacity.

10. The method for calculating the compressive bearing capacity of GFRP tube-constrained UHPC columns considering the fiber winding angle according to claim 8, characterized in that: The ultimate bearing capacity of the GFRP tube-confined core UHPC column under eccentric compression is determined based on the ultimate bearing capacity model of the eccentrically compressed column and the axial compressive strength, including: The axial compressive strength N of the GFRP tube-constrained core UHPC column p The ultimate bearing capacity of the UHPC column with GFRP tube confined core under eccentric compression was obtained by inputting it into the expression of the ultimate bearing capacity model of the eccentrically compressed column.

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