Prediction method of stress-strain curve of rectangular column of rubberized concrete confined by FRP

Abstract

The application provides a FRP-constrained rubber concrete rectangular column stress-strain curve prediction method, which comprises the following steps: obtaining material-related parameters, section-related parameters and measurement-related parameters of the FRP-constrained rubber concrete rectangular column; determining key parameters according to the material-related parameters, the section-related parameters and the measurement-related parameters; constructing a stress-strain curve model based on the key parameters; and predicting the stress-strain curve of the FRP-constrained rubber concrete rectangular column to be predicted based on the stress-strain curve model. The FRP-constrained rubber concrete rectangular column stress-strain relationship curve model provided by the application can accurately and quantitatively predict the stress-strain relationship curve of the FRP-constrained rubber concrete.

Description

Technical Field

[0001] This invention relates to the field of FRP-confined rubber concrete evaluation technology, specifically to a method and apparatus for predicting the stress-strain curve of an FRP-confined rubber concrete rectangular column. Background Technology

[0002] Concrete requires a large amount of natural aggregates, such as sand and gravel, which are not renewable resources. For sustainable development, more and more people are recycling some waste materials to replace some of the natural sand and gravel, preparing rubber concrete. Therefore, applying waste rubber to concrete has enormous potential benefits. Research shows that combining fiber-reinforced polymer (FRP) with rubber concrete to form FRP-confined rubber concrete columns not only maintains the aforementioned advantages of rubber concrete but also improves its load-bearing capacity. Therefore, FRP-confined rubber concrete has broad application prospects in the field of seismic resistance of building structures.

[0003] Determining the stress-strain relationship of the constituent materials of a building structure is a prerequisite for seismic analysis. The confinement effect of FRP on the core rubber concrete is related to the cross-sectional shape of the rubber concrete. In existing technologies, stress-strain relationship models for FRP-confined rubber concrete cylinders have been studied and are relatively mature. However, research on stress-strain relationship models for FRP-confined rubber concrete rectangular columns is very limited. Existing models do not fully consider the influence of material properties and cross-sectional shape, resulting in low accuracy.

[0004] Therefore, there is an urgent need to propose a method and device for predicting the stress-strain curve of FRP-confined rubber concrete rectangular columns, so as to achieve the technical effect of accurately and quantitatively predicting the stress-strain relationship curve of FRP-confined rubber concrete rectangular columns. Summary of the Invention

[0005] In view of this, it is necessary to provide a method and device for predicting the stress-strain curve of FRP-confined rubber concrete rectangular columns, so as to solve the problem that the existing methods for predicting the stress-strain curve of FRP-confined rubber concrete rectangular columns are inaccurate.

[0006] On one hand, the present invention provides a method for predicting the stress-strain curve of an FRP-confined rubber concrete rectangular column, comprising:

[0007] Obtain the material-related parameters, cross-sectional-related parameters, and measurement-related parameters of the FRP-confined rubber concrete rectangular column;

[0008] Key parameters are determined based on the material-related parameters, the cross-section-related parameters, and the measurement-related parameters.

[0009] A stress-strain curve model is constructed based on the aforementioned key parameters;

[0010] The stress-strain curve model is used to predict the stress-strain curve of the FRP-confined rubber concrete rectangular column to be predicted.

[0011] In some possible implementations, the material-related parameters include: the ultimate strain of rubber concrete, the volume replacement rate of rubber particles, the compressive strength of rubber concrete, the pre-set compressive strength of unconfined concrete, the elastic modulus of FRP, the thickness of FRP, and the ultimate strain of FRP; the cross-section-related parameters include: cross-section length, cross-section width, and cross-section chamfer radius; the measurement-related parameters include empirical curvature parameters; and the key parameters include: initial stiffness, elastic limit point, strain-hardening section stiffness, and strain parameters.

[0012] In some possible implementations, the stress-strain curve model is as follows:

[0013]

[0014] In the formula, f c For stress, ε c E is the strain, E1 is the initial stiffness, and ε is the initial stiffness. n f is the strain parameter. o E2 is the elastic limit point, and E2 is the stiffness of the strain-strengthened section.

[0015] In some possible implementations, determining the key parameters based on the material-related parameters, the cross-sectional-related parameters, and the measurement-related parameters includes:

[0016] The initial stiffness is determined based on the compressive strength of the rubber concrete;

[0017] The FRP constraint stress is determined based on the compressive strength of the rubber concrete, the length of the cross section, the width of the cross section, the chamfer radius of the cross section, the volume replacement rate of the rubber particles, and the FRP constraint stress.

[0018] The strain parameters are determined based on the initial stiffness, the elastic limit point, and the empirical curvature parameters.

[0019] In some possible implementations, determining the key parameters based on the material-related parameters, the cross-sectional phase parameters, and the measurement-related parameters further includes:

[0020] Determine the ultimate strain and ultimate strain of the FRP-confined rubber concrete rectangular column.

[0021] The stiffness of the strain-strengthened section is determined based on the ultimate strain of the rubber concrete, the ultimate stress of the FRP-confined rubber concrete rectangular column, and the ultimate strain of the FRP-confined rubber concrete rectangular column.

[0022] In some possible implementations, determining the FRP constraint stress includes:

[0023] The FRP constraint stress is determined based on the elastic modulus of the FRP, the thickness of the FRP, the ultimate strain of the FRP, and the width of the FRP.

[0024] In some possible implementations, determining the ultimate stress of the FRP-confined rubber-concrete rectangular column includes:

[0025] Determine the constraint stiffness and the elastic modulus of the rubber concrete, and determine a first ratio based on the constraint stiffness, the elastic modulus of the rubber concrete, the preset compressive strength of the unconfined concrete, the cross-sectional length, the cross-sectional width, the cross-sectional chamfer radius, the compressive strength of the rubber concrete, the ultimate strain of the FRP, the ultimate strain of the rubber concrete, and the volume replacement rate of the rubber particles.

[0026] The ultimate stress of the FRP-confined rubber concrete rectangular column is determined based on the first ratio and the compressive strength of the rubber concrete.

[0027] In some possible implementations, determining the ultimate strain of the FRP-confined rubber-concrete rectangular column includes:

[0028] The second ratio is determined based on the constraint stiffness, the elastic modulus of the rubber concrete, the preset compressive strength of the unconfined concrete, the cross-sectional length, the cross-sectional width, the cross-sectional chamfer radius, the compressive strength of the rubber concrete, the ultimate strain of the FRP, the ultimate strain of the rubber concrete, and the volume replacement rate of the rubber particles.

[0029] The ultimate strain of the FRP-confined rubber concrete rectangular column is determined based on the second ratio and the ultimate strain of the rubber concrete.

[0030] In some possible implementations, determining the elastic modulus and constraint stiffness of the rubber concrete includes:

[0031] The elastic modulus of the rubber concrete is determined based on its compressive strength.

[0032] The constraint stiffness is determined based on the elastic modulus of the FRP, the thickness of the FRP, and the cross-sectional width.

[0033] On the other hand, the present invention also provides a device for predicting the stress-strain curve of an FRP-confined rubber concrete rectangular column, comprising:

[0034] The data acquisition unit is used to acquire the material-related parameters, cross-sectional-related parameters, and measurement-related parameters of the FRP-confined rubber concrete rectangular column.

[0035] The data processing unit is used to determine key parameters based on the material-related parameters, the cross-section-related parameters, and the measurement-related parameters;

[0036] The model building unit is used to construct a stress-strain curve model based on the key parameters.

[0037] The prediction unit is used to predict the stress-strain curve of the FRP-confined rubber concrete rectangular column to be predicted based on the stress-strain curve model.

[0038] Compared with the prior art, the beneficial effects of the above embodiments are as follows: The stress-strain curve prediction method for FRP-confined rubber concrete rectangular columns provided by the present invention takes into account the influence of the material, cross-sectional shape, and measurement-related parameters of the FRP-confined rubber concrete rectangular columns on the stress-strain curve, obtains material-related parameters, cross-sectional-related parameters, and measurement-related parameters, calculates the key parameters required for the stress-strain relationship based on these three parameters, and constructs a stress-strain curve prediction model through the key parameters, thereby improving the accuracy of predicting the stress-strain curve of FRP-confined rubber concrete rectangular columns; furthermore, the model only needs to obtain the key parameters to predict the stress-strain curve, the model is simple, and the complexity of model prediction is reduced. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 A schematic flowchart of an embodiment of the stress-strain curve prediction method for FRP-confined rubber concrete rectangular columns provided by the present invention;

[0041] Figure 2 A cross-sectional shape diagram of the FRP-confined rubber concrete rectangular column provided by the present invention;

[0042] Figure 3 For the present invention Figure 1 A schematic diagram of an embodiment of step S102;

[0043] Figure 4 For the present invention Figure 1 A schematic diagram of another embodiment of step S102;

[0044] Figure 5 For the present invention Figure 4 A schematic diagram of an embodiment of step S402;

[0045] Figure 6 For the present invention Figure 4 A schematic diagram of another embodiment of step S402;

[0046] Figure 7 For the present invention Figure 5 A schematic diagram of an embodiment of step S501;

[0047] Figure 8 A comparison chart of the predicted stress-strain curve results and experimental results provided by this invention;

[0048] Figure 9 This is a schematic diagram of an embodiment of the stress-strain curve prediction device for FRP-constrained rubber concrete rectangular columns provided by the present invention. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0050] It should be understood that the illustrative drawings are not drawn to scale. The flowcharts used in this invention illustrate operations implemented according to some embodiments of the invention. It should be understood that the operations in the flowcharts may not be implemented in sequence, and steps without logical contextual relationships may be reversed or performed simultaneously. Furthermore, those skilled in the art, guided by the content of this invention, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts.

[0051] Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor systems and / or microcontroller systems.

[0052] This invention provides a method and apparatus for predicting the stress-strain curve of an FRP-confined rubber concrete rectangular column, which will be described below.

[0053] Figure 1 This is a schematic flowchart of an embodiment of the stress-strain curve prediction method for FRP-confined rubber concrete rectangular columns provided by the present invention, as shown below. Figure 1 As shown, the method for predicting the stress-strain curve of FRP-confined rubber concrete rectangular columns includes:

[0054] S101. Obtain the material-related parameters, cross-sectional-related parameters, and measurement-related parameters of the FRP-confined rubber concrete rectangular column;

[0055] S102. Determine the key parameters based on material-related parameters, cross-section-related parameters, and measurement-related parameters;

[0056] S103. Construct a stress-strain curve model based on key parameters;

[0057] S104. Based on the stress-strain curve model, predict the stress-strain curve of the FRP-confined rubber concrete rectangular column to be predicted.

[0058] Compared with the prior art, the beneficial effects of the above embodiments are as follows: The stress-strain curve prediction method for FRP-confined rubber concrete rectangular columns provided by the present invention takes into account the influence of the material, cross-sectional shape, and measurement-related parameters of the FRP-confined rubber concrete rectangular columns on the stress-strain curve. It obtains material-related parameters, cross-sectional-related parameters, and measurement-related parameters, calculates the key parameters required for the stress-strain relationship based on these three parameters, and constructs a stress-strain curve prediction model through the key parameters, thereby improving the accuracy of predicting the stress-strain curve of FRP-confined rubber concrete rectangular columns. Furthermore, the model only needs to obtain the key parameters to predict the stress-strain curve, making the model simple and reducing the complexity of model prediction.

[0059] It should be noted that the stress-strain curve model of the present invention is applicable to the scenario of FRP-confined rubber concrete rectangular columns under monotonic loads.

[0060] In specific embodiments of the present invention, material-related parameters include: ultimate strain of rubber concrete, volume replacement rate of rubber particles, compressive strength of rubber concrete, pre-set compressive strength of unconfined concrete, elastic modulus of FRP, thickness of FRP, and ultimate strain of FRP; cross-section-related parameters include: length, width, and chamfer radius; measurement-related parameters include empirical curvature parameters; key parameters include: initial stiffness, elastic limit point, stiffness of strain-strengthened section, and strain parameters.

[0061] It should be noted that, as Figure 2As shown, the FRP-confined rectangular rubber concrete column has the length of the longer side of the cross-section as its length and the length of the shorter side of the cross-section as its width, that is: h is the length of the cross-section, b is the width of the cross-section, and r is the chamfer radius of the cross-section. The rectangular rubber concrete column can have different cross-section lengths, cross-section widths, and chamfer radii. The outer surface of the rectangular rubber concrete column can be wrapped with two or more layers of FRP in a circumferential direction. The rubber particle content in the rubber concrete can be varied.

[0062] In some embodiments of the present invention, the stress-strain curve model is as follows:

[0063]

[0064] In the formula, f c For stress, ε c E is the strain, E1 is the initial stiffness, and ε is the initial stiffness. n f is the strain parameter. o E2 is the elastic limit point, and E2 is the stiffness of the strain-strengthened section.

[0065] The embodiments of the present invention construct a stress-strain curve model through key parameters. Only four key parameters are needed to predict the stress-strain curve, which reduces the computational complexity of the model.

[0066] In some embodiments of the present invention, such as Figure 3 As shown, step S102 includes:

[0067] S301. Determine the initial stiffness based on the compressive strength of the rubber concrete;

[0068] S302. Determine the FRP confinement stress. Based on the compressive strength of the rubber concrete, the section length, section width, section chamfer radius, rubber particle volume replacement rate, and FRP confinement stress, determine the elastic limit point.

[0069] S303. Determine the strain parameters based on the initial stiffness, elastic limit point, and empirical curvature parameters.

[0070] It should be noted that the empirical curvature parameter refers to the curvature parameter measured in the existing stress-strain curve that controls the entry into the hardening stage.

[0071] In a specific embodiment of the present invention, the initial stiffness calculation formula is as follows:

[0072]

[0073] In the formula, f rc This refers to the compressive strength of rubber concrete.

[0074] The formula for calculating strain parameters is:

[0075]

[0076] In the formula, n is the curvature parameter that controls the stress-strain curve to enter the hardening stage, and n can be specifically 0.8.

[0077] In some embodiments of the present invention, such as Figure 4 As shown, step S102 further includes:

[0078] S401. Determine the ultimate stress and ultimate strain of the FRP-confined rubber concrete rectangular column.

[0079] S402. Determine the stiffness of the strain-strengthened section based on the ultimate strain of the rubber concrete, the ultimate stress of the FRP-confined rubber concrete rectangular column, and the ultimate strain of the FRP-confined rubber concrete rectangular column.

[0080] In a specific embodiment of the present invention, the formula for calculating the elastic limit point is as follows:

[0081]

[0082] In the formula, f l Here, h is the constraint stress of the FRP, b is the section length, r is the chamfer radius, and R is the cross-sectional area. f The volume replacement rate of rubber particles;

[0083] The formula for calculating the stiffness of the strain-hardened section is:

[0084]

[0085] In the formula, f cu ε is the ultimate stress of an FRP-confined rubber-concrete rectangular column. cu The ultimate strain of an FRP-confined rubber-concrete rectangular column.

[0086] In some embodiments of the present invention, the FRP constraint stress is determined based on the elastic modulus of the FRP, the thickness of the FRP, the ultimate strain of the FRP, and the width of the FRP.

[0087] In a specific embodiment of the present invention, the formula for calculating the FRP constraint stress is as follows:

[0088]

[0089] In the formula, E f For the elastic modulus of FRP, t f For the thickness of FRP, ε f The limit strain of FRP.

[0090] In some embodiments of the present invention, such as Figure 5 As shown, step S402 includes:

[0091] S501. Determine the constraint stiffness and elastic modulus of rubber concrete. Based on the constraint stiffness, elastic modulus of rubber concrete, preset unconfined concrete compressive strength, section length, section width, section chamfer radius, compressive strength of rubber concrete, ultimate strain of FRP, ultimate strain of rubber concrete, and volume replacement rate of rubber particles, determine the first ratio.

[0092] S502. Determine the ultimate stress of the FRP-confined rubber concrete rectangular column based on the first ratio and the compressive strength of the rubber concrete.

[0093] In a specific embodiment of the present invention, the formula for calculating the first ratio is:

[0094]

[0095] In the formula, E l To constrain stiffness, E rc ε is the elastic modulus of rubber concrete. rc f is the ultimate strain of rubber concrete. 30 The compressive strength of unconfined C30 concrete is 30 MPa.

[0096] In some embodiments of the present invention, such as Figure 6 As shown, step S402 further includes:

[0097] S601. Determine the second ratio based on the constraint stiffness, elastic modulus of rubber concrete, preset compressive strength of unconfined concrete, section length, section width, section chamfer radius, compressive strength of rubber concrete, ultimate strain of FRP, ultimate strain of rubber concrete, and volume replacement rate of rubber particles.

[0098] S602. Determine the ultimate strain of the FRP-confined rubber concrete rectangular column based on the second ratio and the ultimate strain of the rubber concrete.

[0099] In a specific embodiment of the present invention, the formula for calculating the second ratio is:

[0100]

[0101] In some embodiments of the present invention, such as Figure 7 As shown, step S501 includes:

[0102] S701. Determine the elastic modulus of rubber concrete based on its compressive strength.

[0103] S702. Determine the constraint stiffness based on the elastic modulus of the FRP, the thickness of the FRP, and the width of the cross section.

[0104] In a specific embodiment of the present invention, the formula for calculating the elastic modulus of rubber concrete is as follows:

[0105]

[0106] The formula for calculating constraint stiffness is:

[0107]

[0108] In a specific embodiment of the present invention, the stress-strain curve of an FRP-confined rectangular rubber-concrete column was experimentally tested and predicted, and the two results were compared. In the FRP-confined rectangular rubber-concrete column, the thickness of a single layer of FRP fabric was 0.167 mm, the tensile strength was 4092 MPa, the elastic modulus of FRP was 223.8 GPa, and the strain at FRP failure was 1.82%. The impregnating adhesive was an epoxy resin adhesive supplied by the FRP fabric manufacturer. The cement used was P.O42.5 ordinary Portland cement produced by Hubei Huangshi Huaxin. The coarse aggregate was granite stone with a particle size distribution of 1-5 cm and a density of 2620 kg / m3. The fine aggregate was natural river sand with a particle size distribution of 1-3 mm and a density of 2560 kg / m3. The rubber used was rubber granules produced by Sichuan Sitong Rubber & Plastics Co., Ltd., with a particle size distribution of 1-3 mm. The density of the rubber granules was determined to be 1126 kg / m3 by the drainage method.

[0109] All rectangular rubber-concrete specimens had a height of 300 mm, a short side length of 150 mm, and a chamfer radius r of 45 mm. The parameters varied depending on the length of the specimen cross-section (h), the number of FRP layers covering the specimen, and the rubber volume replacement rate (R). f The long side lengths of the rubber concrete specimens were 150 mm, 187.5 mm, and 225 mm, with 2 or 3 FRP layers and rubber volume replacement rates of 0%, 40%, and 60%, respectively. To minimize the impact of concrete dispersion on the test results, two specimens of each type were prepared. Detailed information on all specimens is shown in Table 1. Specimens were numbered for easy identification. Specimen name J represents a rectangular column, with the suffix number indicating the aspect ratio (h / b); R represents rubber, with the suffix number indicating the rubber replacement rate percentage; L indicates the number of FRP layers; A indicates the first batch of identical specimens; and B indicates the second batch of identical specimens.

[0110] Table 1: Basic Information of Specimens

[0111]

[0112] Test method: On a hydraulic servo press, displacement-controlled loading was applied to FRP-confined rubber concrete rectangular columns at a loading rate of approximately 0.01 mm / s (quasi-static loading) until the specimen failed. Axial load was measured using a force sensor placed under the specimen. Data recording instruments were used to record the readings of the pressure sensor, strain gauge, and displacement meter (LVDT) to obtain the test strain-stress curves for each specimen.

[0113] Taking specimen number J1.25R40L3A as an example, this paper demonstrates the prediction based on a stress-strain model under monotonic loading. The specific method includes the following steps:

[0114] Step 1: Obtain the relevant parameters of the specimen's material and cross-section: the ultimate strain ε of the rubber concrete. rc The volume replacement rate R of the rubber granules is 0.00185. f The compressive strength f of rubber concrete is 40%. rc The elastic modulus E of FRP is 15.32 MPa. f The Pa is 223.8 GPa, and the thickness t of the FRP is... f The ultimate strain ε of FRP is 0.501 mm. f The compressive strength f of unconfined C30 concrete is 0.0182. 30 It is 30 MPa;

[0115] Step 2: Obtain relevant parameters of the specimen cross-section: the aspect ratio of the cross-section is 1.25, and the chamfer radius of the cross-section is 45mm;

[0116] Step 3: Obtain relevant measurement parameters: the empirical curvature parameter n is 0.8;

[0117] Step 4: Calculation of key stress-strain parameters: Based on the FRP constraint stress calculation formula, the FRP constraint stress f is calculated. l The value is 27.21 MPa; based on the elastic limit point calculation formula, the elastic limit point f is calculated. o The initial stiffness is 18.89 MPa; according to the initial stiffness calculation formula, the initial stiffness E1 is calculated to be 18345.28 MPa; according to the constraint stiffness calculation formula, the constraint stiffness E is calculated to be... l The value is 1494.98 MPa; based on the formula for calculating the elastic modulus of rubber concrete, the elastic modulus E of the rubber concrete is calculated. rc The ultimate stress f of the FRP-confined rubber concrete rectangular column is calculated to be 15947.3 MPa. Based on the first ratio calculation formula, the ultimate stress f of the FRP-confined rubber concrete rectangular column is also calculated. cu The ultimate strain ε of the FRP-confined rubber concrete rectangular column is calculated to be 43.29 MPa. Based on the second ratio calculation formula, the ultimate strain ε is obtained. cuThe stiffness E2 of the strain-hardened section is calculated to be 43.29 MPa; according to the formula for calculating the stiffness of the strain-hardened section, the stiffness E2 is calculated to be 458.54 MPa; according to the formula for calculating the strain parameter, the strain parameter ε is calculated to be... n It is 0.00082;

[0118] Step 5: Input the calculated key parameters into the stress-strain model to obtain the predicted stress-strain relationship curve for specimen number J1.25R40L3A.

[0119] Following the steps described above, the stress-strain relationship curves of each specimen were predicted and compared with the experimental results. The stress-strain relationship curves of each specimen were compared with the experimental results, such as... Figure 8 As shown, taking J1.25R60L3A, J1.25R40L3A and J1.25R0L3A as examples, the stress-strain relationship model of FRP-confined rubber concrete rectangular columns under monotonic loads matches the experimental curves well. Other specimens were also compared, and the stress-strain relationship model also matches the experimental curves well. This shows that the prediction method of the present invention is effective and highly accurate, laying the foundation for the application of rubber concrete in building structural engineering.

[0120] To better implement the stress-strain curve prediction method for FRP-confined rubber concrete rectangular columns in this invention, a corresponding stress-strain curve prediction device for FRP-confined rubber concrete rectangular columns is provided, such as... Figure 9 As shown, the stress-strain curve prediction device 900 for FRP-confined rubber concrete rectangular columns includes:

[0121] Data acquisition unit 901 is used to acquire material-related parameters and cross-sectional-related parameters of FRP-confined rubber concrete rectangular columns;

[0122] Data processing unit 902 is used to determine key parameters based on material-related parameters and cross-section-related parameters;

[0123] Model building unit 903 is used to build stress-strain curve models based on key parameters;

[0124] Prediction unit 904 is used to predict the stress-strain curve of the FRP-confined rubber concrete rectangular column to be predicted based on the stress-strain curve model.

[0125] The FRP-constrained rubber concrete rectangular column stress-strain curve prediction device 900 provided in the above embodiments can realize the technical solutions described in the above embodiments of the FRP-constrained rubber concrete rectangular column stress-strain curve prediction method. The specific implementation principles of each module or unit can be found in the corresponding content in the above embodiments of the FRP-constrained rubber concrete rectangular column stress-strain curve prediction device, which will not be repeated here.

[0126] The above provides a detailed description of the method and apparatus for predicting the stress-strain curve of FRP-confined rubber concrete rectangular columns provided by the present invention. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for predicting the stress-strain curve of an FRP-confined rubber concrete rectangular column, characterized in that, include: Obtain the material-related parameters, cross-sectional-related parameters, and measurement-related parameters of the FRP-confined rubber concrete rectangular column; Key parameters are determined based on the material-related parameters, the cross-sectional parameters, and the measurement-related parameters. The material-related parameters include: ultimate strain of rubber concrete, volume replacement rate of rubber particles, compressive strength of rubber concrete, preset compressive strength of unconfined concrete, elastic modulus of FRP, thickness of FRP, and ultimate strain of FRP. The cross-sectional parameters include: cross-sectional length, cross-sectional width, and cross-sectional chamfer radius. The measurement-related parameters include empirical curvature parameters. The key parameters include: initial stiffness, elastic limit point, strain-hardening section stiffness, and strain parameters. Based on the aforementioned key parameters, a stress-strain curve model is constructed. The stress-strain curve model is as follows: In the formula, f c For stress, ε c In response, E 1 represents the initial stiffness. ε n For strain parameters, f o It is the elastic limit point. E 2 represents the stiffness of the strain-strengthened section; The stress-strain curve of the FRP-confined rubber concrete rectangular column to be predicted is based on the stress-strain curve model. The determination of key parameters based on the material-related parameters, the cross-sectional-related parameters, and the measurement-related parameters includes: Determine the ultimate stress and ultimate strain of the FRP-confined rubber concrete rectangular column. The stiffness of the strain-strengthened section is determined based on the ultimate strain of the rubber concrete, the ultimate stress of the FRP-confined rubber concrete rectangular column, and the ultimate strain of the FRP-confined rubber concrete rectangular column. Determining the ultimate stress of an FRP-confined rubber concrete rectangular column includes: The constraint stiffness and the elastic modulus of the rubber concrete are determined. A first ratio is determined based on the constraint stiffness, the elastic modulus of the rubber concrete, the preset unconfined concrete compressive strength, the cross-sectional length, the cross-sectional width, the cross-sectional chamfer radius, the compressive strength of the rubber concrete, the ultimate strain of the FRP, the ultimate strain of the rubber concrete, and the volume replacement rate of the rubber particles. The formula for calculating the first ratio is: In the formula, E l To constrain stiffness, E rc This refers to the elastic modulus of rubber concrete. ε rc This represents the ultimate strain of the rubber-concrete composite. f 30 The compressive strength of unconfined C30 concrete is 30 MPa. The ultimate stress of the FRP-confined rubber concrete rectangular column is determined based on the first ratio and the compressive strength of the rubber concrete. The determination of the ultimate strain of the FRP-confined rubber concrete rectangular column includes: The second ratio is determined based on the constraint stiffness, the elastic modulus of the rubber concrete, the pre-set compressive strength of the unconfined concrete, the cross-sectional length, the cross-sectional width, the chamfer radius of the cross-section, the compressive strength of the rubber concrete, the ultimate strain of the FRP, the ultimate strain of the rubber concrete, and the volume replacement rate of the rubber particles. The formula for calculating the second ratio is as follows: ； The ultimate strain of the FRP-confined rubber concrete rectangular column is determined based on the second ratio and the ultimate strain of the rubber concrete.

2. The method for predicting the stress-strain curve of an FRP-confined rubber concrete rectangular column according to claim 1, characterized in that, The determination of key parameters based on the material-related parameters, the cross-sectional-related parameters, and the measurement-related parameters includes: The initial stiffness is determined based on the compressive strength of the rubber concrete; The FRP constraint stress is determined based on the compressive strength of the rubber concrete, the length of the cross section, the width of the cross section, the chamfer radius of the cross section, the volume replacement rate of the rubber particles, and the FRP constraint stress. The strain parameters are determined based on the initial stiffness, the elastic limit point, and the empirical curvature parameters.

3. The method for predicting the stress-strain curve of an FRP-confined rubber concrete rectangular column according to claim 2, characterized in that, The determination of FRP constraint stress includes: The FRP constraint stress is determined based on the elastic modulus of the FRP, the thickness of the FRP, the ultimate strain of the FRP, and the cross-sectional width.

4. The method for predicting the stress-strain curve of an FRP-confined rubber concrete rectangular column according to claim 1, characterized in that, The determination of the constraint stiffness and the elastic modulus of the rubber concrete includes: The elastic modulus of the rubber concrete is determined based on its compressive strength. The constraint stiffness is determined based on the elastic modulus of the FRP, the thickness of the FRP, and the cross-sectional width.

5. A device for predicting the stress-strain curve of an FRP-confined rubber concrete rectangular column, used to execute the method for predicting the stress-strain curve of an FRP-confined rubber concrete rectangular column as described in any one of claims 1-4, characterized in that, include: The data acquisition unit is used to acquire the material-related parameters, cross-sectional-related parameters, and measurement-related parameters of the FRP-confined rubber concrete rectangular column. The data processing unit is used to determine key parameters based on the material-related parameters, the cross-section-related parameters, and the measurement-related parameters; The model building unit is used to construct a stress-strain curve model based on the key parameters. The prediction unit is used to predict the stress-strain curve of the FRP-confined rubber concrete rectangular column to be predicted based on the stress-strain curve model.

Images