Calculation method and device for bond-slip constitutive relationship between retard-bonded prestressed tendon and concrete, electronic equipment and readable medium

Abstract

The embodiment of the invention discloses a calculation method and device for a bond-slip constitutive relation between a retard-bonded prestressed tendon and concrete, electronic equipment and a readable medium. The calculation method comprises the following steps that a bond-slip constitutive relation model, related to characteristic parameters, of the retard-bonded prestressed tendon and the concrete is established; obtaining test data of a bonding performance test of the retard-bonded prestressed tendon and concrete to draw a bonding stress-bonding slip curve; and on the basis of the test data and the bond stress-bond slip curve, solving characteristic parameters in the bond slip constitutive relation model. The curve of the bond-slip constitutive relation model provided by the invention has high goodness of fit with an actual test curve, is high in universality, and can be basically suitable for all types of retard-bonded prestressed tendons and concrete.

Description

Technical Field

[0001] The present invention belongs to the technical field of research on the bond-slip constitutive relationship of concrete, and particularly relates to a calculation method, device, electronic device and readable medium for the bond-slip constitutive relationship between a slowly bonded prestressed tendon and concrete. Background Art

[0002] With the continuous expansion of the engineering field, people's requirements for the comprehensive performance of concrete structures are getting higher and higher. Ordinary reinforced concrete structures can no longer fully meet the needs of projects in harsh environments due to problems such as poor durability and low strength. Slowly bonded prestressed tendons, as a new type of composite material with excellent corrosion resistance and tensile properties, can effectively solve the durability and strength problems caused by the corrosion of prestressed tendons. Ultra High Performance Concrete (UHPC) is a fiber-reinforced cement-based composite material with high strength, high toughness, high durability and high fluidity, and has extremely strong bonding performance with slowly bonded prestressed tendons, which can greatly shorten the bonding length between the overlapping steel bars and prestressed tendons of slowly bonded prestressed tendons, making UHPC widely used in the wet joint connection of concrete structures and the node connection of prefabricated building structures. Slowly bonded prestressed tendons only need a relatively small straight anchorage length to meet the force requirements of the structure, reducing on-site wet operations and improving construction efficiency.

[0003] For concrete structures, the common working of slowly bonded prestressed tendons and concrete is an important guarantee for their mechanical properties. The cooperative performance between slowly bonded prestressed tendons and concrete can be represented by the bond-slip constitutive relationship between the two.

[0004] However, in the prior art, the bond stress-bond slip curve obtained based on the bond-slip constitutive relationship has a poor degree of coincidence with the bond stress-bond slip curve obtained from actual tests. And the generality of the existing bond-slip constitutive relationship is also poor, and it can only be applied to slowly bonded prestressed tendons and concrete with specific physical parameters.

[0005] The information disclosed in this background art section is only intended to enhance the overall understanding of the present invention and should not be regarded as an admission or any form of implication that this information constitutes prior art already known to those of ordinary skill in the art. Summary of the Invention

[0006] The purpose of the present invention is to provide a calculation method for the bond-slip constitutive relationship between a slowly bonded prestressed tendon and concrete, which is used to solve the problems of large errors and poor generality of the existing bond-slip constitutive relationship.

[0007] In a first aspect, to achieve the above object, a specific embodiment of the present invention provides a calculation method for the bond-slip constitutive relationship between a slow-bonded prestressed tendon and concrete, including the following steps:

[0008] Establish a bond-slip constitutive relationship model between the slow-bonded prestressed tendon and concrete related to characteristic parameters;

[0009] Obtain the test data of the bond performance test between the slow-bonded prestressed tendon and concrete to draw the bond stress-bond slip curve;

[0010] Based on the test data and the bond stress-bond slip curve, solve the characteristic parameters in the bond-slip constitutive relationship model.

[0011] In one or more embodiments of the present invention, the characteristic parameters include the bond stress τ at the elastic point in the bond stress-bond slip curve e , the bond stress τ at the peak point in the bond stress-bond slip curve u , the bond stress τ at the residual point in the bond stress-bond slip curve r , the bond slip s at the elastic point in the bond stress-bond slip curve e , the bond slip s at the peak point in the bond stress-bond slip curve u , and the bond slip s at the residual point in the bond stress-bond slip curve r or one or more of them.

[0012] In one or more embodiments of the present invention, the bond-slip constitutive relationship model includes:

[0013] Micro-slip segment:

[0014] Slip segment:

[0015] Descending segment:

[0016] Residual segment:

[0017] where τ is the bond stress, s is the bond slip, 0 < α1 ≤ 1, 0 < α2 ≤ 1, w is the bond stress of the residual segment in its local coordinate system, u is the bond slip of the residual segment in its local coordinate system, Δw is the average value of the bond stress amplitudes of all cycles of the residual segment in its local coordinate system, Δu is the average value of the bond slip amplitudes of all cycles of the residual segment in its local coordinate system, and θ is the angle between the local coordinate system where the residual segment is located and the original coordinate system.

[0018] In one or more embodiments of the present invention, solving the characteristic parameters in the bond-slip constitutive relation model includes: fitting the correlation between the characteristic parameters, the parameters of the slow-bonded prestressed tendons, and the concrete parameters based on the test data of the bond performance test to obtain the fitting model of the characteristic parameters.

[0019] In one or more embodiments of the present invention, the bond stress τ at the elastic point in the bond stress-bond slip curve e The fitting model is:

[0020]

[0021] The bond stress τ at the peak point in the bond stress-bond slip curve u The fitting model is:

[0022]

[0023] The bond stress τ at the residual point in the bond stress-bond slip curve r The fitting model is:

[0024] τ r = k3×τ u + b3;

[0025] The bond slip s at the elastic point in the bond stress-bond slip curve e The fitting model is:

[0026]

[0027] The bond slip s at the peak point in the bond stress-bond slip curve u The fitting model is:

[0028]

[0029] The bond slip s at the residual point in the bond stress-bond slip curve r The fitting model is:

[0030] s r = b6;

[0031] Wherein, k1 to k9, b1 to b6, n1 to n6, and m1 to m6 are all fitting constants, d is the diameter of the slow-bonded steel strand, c is the protective layer thickness between the outer edge of the slow-bonded prestressed tendon and the outer edge of the concrete, L cb is the bond length between the slow-bonded prestressed tendon and the concrete, L tb is the length of the slow-bonded prestressed tendon that is not bonded to the concrete, and f is the standard value of the axial compressive strength of the concrete.

[0032] In one or more embodiments of the present invention, the bond stress τ at the elastic point in the bond stress-bond slip curve e has a fitting model as follows:

[0033]

[0034] The bond stress τ at the peak point in the bond stress-bond slip curve u has a fitting model as follows:

[0035]

[0036] The bond stress τ at the residual point in the bond stress-bond slip curve r has a fitting model as follows:

[0037] τ r = 0.72τ u ;

[0038] The bond slip s at the elastic point in the bond stress-bond slip curve e has a fitting model as follows:

[0039]

[0040] The bond slip s at the peak point in the bond stress-bond slip curve u has a fitting model as follows:

[0041]

[0042] The bond slip s at the residual point in the bond stress-bond slip curve r has a fitting model as follows:

[0043] s r = 6.72.

[0044] In one or more embodiments of the present invention, the bond slip constitutive relation model of the residual segment in the local coordinate system is converted into its bond slip constitutive relation model in the original coordinate system according to the following formula:

[0045]

[0046] u = (s - s r )cosθ - (τ - τ r )sinθ;

[0047] Δw = Δτcosθ;

[0048] Δu = Δs / cosθ;

[0049] Δτ = k 10 ×τ u ;

[0050] Δs = b7;

[0051] θ = k 11 ×τ u ;

[0052] wherein, k 10 , k 11 and b7 are all fitting constants, Δτ is the average value of the bond stress amplitudes of all cycles of the residual segment in the original coordinate system, and Δs is the average value of the bond slip amplitudes of all cycles of the residual segment in the original coordinate system.

[0053] In a second aspect, the present invention further provides a calculation device for the bond-slip constitutive relationship between a slow-bonded prestressed tendon and concrete, including a model acquisition module, a data acquisition module, and a data processing module. The model acquisition module is used to establish a bond-slip constitutive relationship model related to characteristic parameters for the slow-bonded prestressed tendon and concrete. The data acquisition module is used to acquire the test data of the bond performance test of the slow-bonded prestressed tendon and concrete, and draw a bond stress-bond slip curve based on the test data. The data processing module is used to solve the characteristic parameters in the bond-slip constitutive relationship model based on the test data and the bond stress-bond slip curve.

[0054] In a third aspect, the present invention further provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein when the processor executes the program, it implements the above-mentioned calculation method for the bond-slip constitutive relationship between the slow-bonded prestressed tendon and concrete.

[0055] In a fourth aspect, the present invention further provides a computer-readable medium, which carries computer-executable instructions, and when the computer-executable instructions are executed by a processor, they are used to implement the calculation method for the bond-slip constitutive relationship between the slow-bonded prestressed tendon and concrete as described above.

[0056] Compared with the prior art, the present invention proposes a bond-slip constitutive relationship model related to characteristic parameters for the slow-bonded prestressed tendon and concrete, and solves the characteristic parameters of the bond-slip constitutive relationship model through the bond performance test of the slow-bonded prestressed tendon and concrete.

[0057] Secondly, the bond-slip constitutive relationship model proposed by the present invention has a high degree of coincidence with the actual test curve.

[0058] In addition, the bond-slip constitutive relationship model proposed by the present invention has strong versatility and can basically be applied to all types of slow-bonded prestressed tendons and concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0060] Figure 1 It is a flowchart of the calculation method for the bond-slip constitutive relationship between the slow-bonded prestressed tendon and concrete in an embodiment of the present invention;

[0061] Figure 2 It is a curve graph of the bond-slip constitutive relationship model in an embodiment of the present invention;

[0062] Figure 3 It is a structural schematic diagram of the specimen size in an embodiment of the present invention;

[0063] Figure 4 It is a curve graph of the test data of the specimen numbered FS1C5L20 in an embodiment of the present invention;

[0064] Figure 5 It is a curve graph of the test data of the specimen numbered FS1C5L42 in an embodiment of the present invention;

[0065] Figure 6 It is a curve graph of the test data of the specimen numbered FS1C5L82 in an embodiment of the present invention;

[0066] Figure 7 It is a curve graph of the test data of the specimen numbered YS1C5L22-2 in an embodiment of the present invention;

[0067] Figure 8 It is a structural schematic diagram of the calculation device for the bond-slip constitutive relationship between the slow-bonded prestressed tendon and concrete in an embodiment of the present invention;

[0068] Figure 9 It is a structural schematic diagram of an electronic device in an embodiment of the present invention. Specific embodiments

[0069] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0070] Refer toFigure 1 As shown, it is a flowchart of a calculation method for the bond-slip constitutive relationship between a slow-bonded prestressed tendon and concrete in an embodiment of the present invention. This calculation method for the bond-slip constitutive relationship between a slow-bonded prestressed tendon and concrete can be basically applicable to all types of slow-bonded prestressed tendons and all types of concrete, and specifically includes the following steps:

[0071] S1. Establish a bond-slip constitutive relationship model related to characteristic parameters for the slow-bonded prestressed tendon and concrete.

[0072] Specifically, in this step, a corresponding bond-slip constitutive relationship model is established based on the bond stress τ - bond slip s curve of the slow-bonded prestressed tendon and concrete.

[0073] Referring to Figure 2 As shown, the bond stress - bond slip curve basically consists of four stages, namely the micro-slip stage, the slip stage, the descending stage, and the residual stage. The correlation between the bond stress and the bond slip in each stage has obvious differences. Therefore, different bond-slip constitutive relationship models need to be established for each stage.

[0074] S11. Establish a slip constitutive relationship model for the micro-slip stage.

[0075] In the micro-slip stage, the grip force of the concrete on the slow-bonded prestressed tendon just starts to play a role. The cooperative working performance between the slow-bonded prestressed tendon and the concrete is good. Only a small relative slip occurs between the slow-bonded prestressed tendon and the concrete, and the bond stress and the bond slip are approximately linearly related. Therefore, a power-law fitting model can be used to establish the slip constitutive relationship model for the micro-slip stage. The formula for the slip constitutive relationship model in the micro-slip stage is as follows:

[0076]

[0077] where τ e is the bond stress at the elastic point in the bond stress - bond slip curve, s e is the bond slip at the elastic point in the bond stress - bond slip curve, and α1 is greater than 0 and less than or equal to 1.

[0078] S12. Establish a slip constitutive relationship model for the slip stage.

[0079] In the slip segment, as the bond stress increases, the growth rate of bond slip accelerates. At this time, the micro-cracks inside the concrete begin to develop, and the connection between the slow-bonded prestressed tendon and the concrete is gradually damaged. Before the bond stress reaches the peak in this stage, the bond performance between the concrete and the slow-bonded prestressed tendon begins to show obvious degradation, and the bond slip increases rapidly. Although the cooperative working ability between the bond stress and the bond slip is gradually weakening, the cooperative working ability between the two still remains at a relatively high level. Therefore, the power-law fitting model can also be used to establish the slip constitutive relationship model in the slip segment. The formula for the slip constitutive relationship model in the slip segment is as follows:

[0080]

[0081] Among them, τ u is the bond stress at the peak point in the bond stress-bond slip curve, s u is the bond slip at the peak point in the bond stress-bond slip curve, and α2 is greater than 0 and less than or equal to 1.

[0082] S13. Establish the slip constitutive relationship model for the descending segment.

[0083] In the descending segment, the bond stress begins to show a gradually decreasing trend after reaching the peak. At this time, the cracks in the concrete further expand, and local slip or even partial extraction of the slow-bonded prestressed tendon may occur, thus showing a trend of rapid decrease in bond stress while continuous increase in bond slip. The bond between the slow-bonded prestressed tendon and the concrete has been damaged to a large extent, and the bearing capacity and deformation performance are significantly affected.

[0084] Considering that there is a linear relationship between the bond stress and the bond slip in the descending segment, the linear fitting model can be used to establish the slip constitutive relationship model for the descending segment. The formula for the slip constitutive relationship model in the descending segment is as follows:

[0085]

[0086] Among them, τ r is the bond stress at the residual point in the bond stress-bond slip curve, s r is the bond slip at the residual point in the bond stress-bond slip curve.

[0087] S14. Establish the slip constitutive relationship model for the residual segment.

[0088] In the residual section, the bond stress basically remains at a relatively low stress level, while the bond slip continues to increase slowly. At this time, although there is still a certain connection between the slow-bonded prestressed tendon and the concrete, the bond performance has become very weak. Under the action of the residual bond stress, relatively large deformations may occur, and these deformations are mainly caused by the slip of the slow-bonded prestressed tendon.

[0089] Considering that the shape of the residual section in the bond stress-bond slip curve approximately presents the form of a sine-cosine function curve, a slip constitutive relationship model for the descending section can be established using the sine-cosine function curve model. The formula for the slip constitutive relationship model of the residual section is as follows:

[0090]

[0091] where w is the bond stress of the residual section in its local coordinate system, u is the bond slip of the residual section in its local coordinate system, Δw is the average value of the bond stress amplitudes of all cycles of the residual section in its local coordinate system, and Δu is the average value of the bond slip amplitudes of all cycles of the residual section in its local coordinate system.

[0092] Furthermore, the above formula is established based on the local coordinate system where the descending section is located, and it is necessary to convert the above formula into the formula in the original coordinate system of the descending section.

[0093] Referring to Figure 2 as shown, based on the existing coordinate transformation principle, it can be clearly obtained that there is the following relationship between the bond stress w of the residual section in its local coordinate system and the bond slip u of the residual section in its local coordinate system and the characteristic parameters:

[0094]

[0095] u = (s - s r )cosθ - (τ - τ r )sinθ.

[0096] Δw = Δτ × cosθ.

[0097] Δu = Δs / cosθ.

[0098] where Δτ is the average value of the bond stress amplitudes of all cycles of the residual section in the original coordinate system, Δs is the average value of the bond slip amplitudes of all cycles of the residual section in the original coordinate system, and θ is the angle between the local coordinate system (w - u coordinate system) where the residual section is located and the original coordinate system (the coordinate system where the bond stress-bond slip curve is located, i.e., the τ - s coordinate system).

[0099] Based on the above formula, the formula for the slip constitutive relationship model of the residual section can finally be converted into the formula in the original coordinate system.

[0100] As can be seen from the formulas in steps S11 to S14, the characteristic parameters related to the slip constitutive relation model generally include the bond stress τ at the elastic point in the bond stress-bond slip curve e , the bond stress τ at the peak point in the bond stress-bond slip curve u , the bond stress τ at the residual point in the bond stress-bond slip curve r , the bond slip s at the elastic point in the bond stress-bond slip curve e , the bond slip s at the peak point in the bond stress-bond slip curve u , and the bond slip s at the residual point in the bond stress-bond slip curve r .

[0101] In addition, in addition to the above characteristic parameters, there are also the following relatively important key parameters:

[0102] The average value Δτ of the bond stress amplitudes of all cycles of the residual segment in the original coordinate system, the average value Δs of the bond slip amplitudes of all cycles of the residual segment in the original coordinate system, and the angle θ between the local coordinate system where the residual segment is located and the original coordinate system.

[0103] Therefore, in the subsequent steps, the methods for obtaining the characteristic parameters and key parameters will be introduced.

[0104] S2. Obtain the test data of the bond performance test of the slow-bonded prestressed tendon and concrete to draw the bond stress-bond slip curve.

[0105] Specifically, in order to improve the generality of the slip constitutive relation model in step S1, a large number of bond performance tests can be designed. Different types of slow-bonded prestressed tendons and concrete need to be used during the experiment. Through the test data, the fitting formulas of the above characteristic parameters and key parameters are fitted, which is more convenient for the popularization and application of the slip constitutive relation model.

[0106] Based on the test data, draw the corresponding bond stress-bond slip curve. The forms of the bond stress-bond slip curves corresponding to all specimens can generally be referred to Figure 2 .

[0107] S3. Based on the bond stress-bond slip curve, solve the characteristic parameters in the bond slip constitutive relation model.

[0108] Specifically, in this step, based on the test data of the bond performance test, the correlations between the characteristic parameters and key parameters in the test data and the parameters of the slow-bonded prestressed tendon and concrete are fitted to obtain the fitting models of the characteristic parameters and key parameters.

[0109] Based on the previous test data, the correlation fitting models between the characteristic parameters and the parameters of the slowly-bonded prestressed tendons and concrete can refer to the following fitting models.

[0110] The bond stress τ at the elastic point in the bond stress-bond slip curve e The fitting model is:

[0111]

[0112] The bond stress τ at the peak point in the bond stress-bond slip curve u The fitting model is:

[0113]

[0114] The bond stress τ at the residual point in the bond stress-bond slip curve r The fitting model is:

[0115] τ r = k3×τ u + b3.

[0116] The bond slip s at the elastic point in the bond stress-bond slip curve e The fitting model is:

[0117]

[0118] The bond slip s at the peak point in the bond stress-bond slip curve u The fitting model is:

[0119]

[0120] The bond slip s at the residual point in the bond stress-bond slip curve r The fitting model is:

[0121] s r = b6.

[0122] Among them, k1 to k9, b1 to b6, n1 to n6, and m1 to m6 in the above fitting models are all fitting constants and need to be obtained after fitting according to the test data.

[0123] In addition, in the above fitting models, d is the diameter of the slowly-bonded steel strand, c is the protective layer thickness between the outer edge of the slowly-bonded prestressed tendon and the outer edge of the concrete, L cb is the bond length between the slowly-bonded prestressed tendon and the concrete, L tb is the length of the slowly-bonded prestressed tendon that is not bonded to the concrete, and f is the standard value of the axial compressive strength of the concrete.

[0124] In addition, since there are not only characteristic parameters but also key parameters in the bond-slip constitutive relation model, in order to simplify the bond-slip constitutive relation model, the correlation between the characteristic parameters and the key parameters can be further fitted, so that only the characteristic parameters exist in the bond-slip constitutive relation model finally.

[0125] Based on the previous test data, the fitting models of the characteristic parameters and the key parameters are as follows.

[0126] Δτ = k 10 ×τ u 。

[0127] Δs = b7.

[0128] θ = k 11 ×τ u 。

[0129] The above are the general steps of the calculation method for the bond-slip constitutive relation between the slow-bonded prestressed tendon and the concrete in the present invention.

[0130] One of the optional test schemes is introduced below, and the feasibility of the above method is verified by combining specific test data.

[0131] The diameters of the slow-bonded prestressed tendons used in the test are 15.2 mm, 17.8 mm and 21.8 mm, all of the same production batch, the standard tension service life is 6010 days, and the standard curing time is 18030 days. The materials meet the specification requirements in JG / T 369-2012 "Slow-bonded Prestressed Steel Strands" and JG / T 370-2012 "Special Adhesive for Slow-bonded Prestressed Steel Strands".

[0132] The concrete used in the test includes ordinary concrete and ultra-high performance concrete.

[0133] The ordinary concrete used in the test is C30, C50, C60. For each type of ordinary concrete, three standard cube specimens of 150 mm × 150 mm × 150 mm are made to measure the cube compressive strength f cu , and three prism specimens of 150 mm × 150 mm × 300 mm are made to measure the axial compressive strength f c 。

[0134] The ultra-high performance concrete used in the test is UC150, and the strength grade is 100 MPa to 200 MPa. Three standard cube specimens of 100 mm × 100 mm × 100 mm and prism specimens of 100 mm × 100 mm × 300 mm are made for the ultra-high performance concrete to measure the cube compressive strength and axial compressive strength of the ultra-high performance concrete.

[0135] The measured cube compressive strength and axial compressive strength of normal concrete and ultra-high performance concrete are shown in Table 1.

[0136] Table 1 - Mechanical property indexes of concrete

[0137] C30 C50 C60 UC150 <![CDATA[f cu / MPa]]> 34.63 48.16 68.11 150 <![CDATA[f c / MPa]]> 30.13 37.24 65.11 129.5

[0138] There are two types of center pullout specimens used in this test, namely rectangular parallelepiped specimens and cylindrical specimens. The specimen sizes refer to Figure 3 as shown. Among them, the rectangular parallelepiped specimen is a typical pullout specimen. The side length of the rectangular parallelepiped section is 150 mm, and stirrups of A6@40 are provided inside. The cylindrical specimen follows the standard specimen for strand bonding (STSB) adopted by the American Society for Testing and Materials (ASTM). The diameter of the cross-section of the cylindrical specimen is 125 mm, and a steel sleeve with a thickness of 3 mm is provided outside. In order to avoid stress concentration at the loading end and make the bond stress distribution more uniform, a non-bonded section with a length of 50 mm is provided at the loading end. The slow-bonded prestressed tendon is sleeved in a PVC casing and wrapped with double-sided sponge tape to prevent the entry of concrete slurry, so that the casing does not move during the vibration process and the bond conditions of the slow-bonded prestressed tendon are ensured to be consistent. The main information of all specimens for the center pullout of the slow-bonded prestressed tendon is shown in Table 2, where d represents the diameter of the steel strand of the slow-bonded prestressed tendon, L cb represents the bond length between the slow-bonded prestressed tendon and the concrete, and L tb represents the self-bond length of the slow-bonded prestressed tendon outside the concrete, that is, the sum of the length of the PVC casing and the length of the sheath of the slow-bonded prestressed tendon outside the specimen. The slow-bonded prestressed tendon does not bond with the concrete within the length range of L tb .

[0139] The meaning of the specimen numbers: F represents the rectangular parallelepiped specimen, and Y represents the cylindrical specimen. S1, S2, and S3 respectively represent slow-bonded prestressed tendons with steel strand diameters of 15.2 mm, 17.8 mm, and 21.6 mm. C3, C5, C6, and UC respectively represent normal concrete C30, C50, C60, and ultra-high performance concrete UC150.

[0140] Table 2 - Test data of specimens for center pullout of slow-bonded prestressed tendon

[0141]

[0142] The test data obtained from the above test design scheme are shown in Table 3.

[0143] Table 3 - Calculated values of characteristic parameters

[0144]

[0145]

[0146] After performing a correlation fitting on the corresponding test data in Tables 2 and 3, a fitting model for each key parameter can be obtained as shown below.

[0147] The bond stress τ at the elastic point in the bond stress - bond slip curve e has a fitting model of:

[0148]

[0149] The bond stress τ at the peak point in the bond stress - bond slip curve u has a fitting model of:

[0150]

[0151] The bond stress τ at the residual point in the bond stress - bond slip curve r has a fitting model of:

[0152] τ r = 0.72τ u .

[0153] The bond slip s at the elastic point in the bond stress - bond slip curve e has a fitting model of:

[0154]

[0155] The bond slip s at the peak point in the bond stress - bond slip curve u has a fitting model of:

[0156]

[0157] The bond slip s at the residual point in the bond stress - bond slip curve r has a fitting model of:

[0158] s r = 6.72.

[0159] In addition, based on the test data, fitting models for the characteristic parameters and key parameters can also be obtained as shown below.

[0160] Δτ = 0.223τ u .

[0161] Δs = 11.57.

[0162]

[0163] Based on the above test data, bond slip constitutive relation models, and fitting models, corresponding test curves and model curves can be plotted. The curve graphs for some test schemes can be referred to Figures 4 to 7as shown, where Figure 4 is the corresponding curve of the specimen with the number FS1C5L20, Figure 5 is the corresponding curve of the specimen with the number FS1C5L42, Figure 6 is the corresponding curve of the specimen with the number FS1C5L82, Figure 7 is the corresponding curve of the specimen with the number YS1C5L22-2.

[0164] Based on Figures 4 to 7 the curve shapes shown, it can be seen that the bond-slip constitutive relationship model proposed by the present invention has a high degree of agreement with the actual test data. Moreover, the bond-slip constitutive relationship model proposed by the present invention has strong generality and can basically be applied to all types of slow-bonded prestressed tendons and concrete.

[0165] Referring to Figure 8 as shown, based on the same inventive concept as the foregoing method, an embodiment of the present invention further proposes a calculation device 1 for the bond-slip constitutive relationship between slow-bonded prestressed tendons and concrete, including a model acquisition module 11, a data acquisition module 12, and a data processing module 13. The model acquisition module 11 is used to establish a bond-slip constitutive relationship model related to characteristic parameters of slow-bonded prestressed tendons and concrete. The data acquisition module 12 is used to acquire the test data of the bond performance test of slow-bonded prestressed tendons and concrete, and draw a bond stress-bond slip curve based on the test data. The data processing module 13 is used to solve the characteristic parameters in the bond-slip constitutive relationship model based on the bond stress-bond slip curve.

[0166] Referring to Figure 9 as shown, an embodiment of the present invention further provides an electronic device 2, which includes at least one processor 21, a memory 22 (such as a non-volatile memory), a memory 23, and a communication interface 24, and at least one processor 21, the memory 22, the memory 23, and the communication interface 24 are connected together via an internal bus 25. The at least one processor 21 is used to call at least one program instruction stored or encoded in the memory 22 so that the at least one processor 21 executes various operations and functions of the bond-slip constitutive relationship calculation method between slow-bonded prestressed tendons and concrete described in various embodiments of this specification.

[0167] In the embodiments of the present invention, the electronic device 2 may include, but is not limited to: personal computers, server computers, workstations, desktop computers, laptop computers, notebook computers, mobile electronic devices, smart phones, tablet computers, cellular phones, personal digital assistants (PDAs), handheld devices, messaging devices, wearable electronic devices, consumer electronic devices, and the like.

[0168] An embodiment of the present invention also provides a computer-readable storage medium. The computer-readable storage medium may have instructions (i.e., the elements implemented in software as described above). When these instructions are executed by a machine, the machine is caused to perform the various operations and functions described above in connection with the various embodiments of this specification. Figures 1 to 9 Specifically, a system or device equipped with a readable storage medium may be provided. On this readable storage medium, software program code for implementing the functions of any one of the above-described embodiments is stored, and the computer or processor of the system or device is caused to read and execute the instructions stored in the readable storage medium.

[0169] The computer-readable medium in the present invention may be a computer-readable signal medium, a computer-readable storage medium, or any combination of the two. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of the computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, 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), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present invention, the computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0170] In the present invention, the computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, which carries the computer-readable program code. Such a propagated data signal may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The computer-readable signal medium may also be any computer-readable medium other than the computer-readable storage medium, which can send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wire, optical fiber, RF, etc., or any suitable combination of the above.

[0171] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0172] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses, systems, and computer program products according to the embodiments of the present invention. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams, can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for realizing the functions specified in one Figure 1 one flow or multiple flows and / or blocks Figure 1 means for realizing the functions specified in one block or multiple blocks.

[0173] The foregoing description of specific exemplary embodiments of the present invention is for the purposes of illustration and exemplification. These descriptions are not intended to limit the present invention to the precise forms disclosed, and obviously, many changes and variations are possible in light of the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical applications, so that those skilled in the art can implement and utilize various different exemplary embodiments of the present invention, as well as various different selections and changes. The scope of the present invention is intended to be defined by the claims and their equivalents.

[0174] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, in any regard, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes falling within the meaning and scope of the equivalent elements of the claims in the present invention. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0175] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment contains only an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A calculation method for the bond-slip constitutive relationship between a slow-bonded prestressed tendon and concrete, characterized in that, It includes the following steps: Establish a bond-slip constitutive relationship model between the slow-bonded prestressed tendon and concrete related to characteristic parameters; Obtain the test data of the bond performance test of the slow-bonded prestressed tendon and concrete to draw the bond stress-bond slip curve; Based on the test data and the bond stress-bond slip curve, solve the characteristic parameters in the bond-slip constitutive relationship model.

2. The calculation method for the bond-slip constitutive relationship between the slow-bonded prestressed tendon and concrete according to claim 1, wherein The characteristic parameters include the bond stress τ at the elastic point in the bond stress-bond slip curve e , the bond stress τ at the peak point in the bond stress-bond slip curve u , the bond stress τ at the residual point in the bond stress-bond slip curve r , the bond slip s at the elastic point in the bond stress-bond slip curve e , the bond slip s at the peak point in the bond stress-bond slip curve u and the bond slip s at the residual point in the bond stress-bond slip curve r or one or more of them.

3. The calculation method of the bond-slip constitutive relationship between the slow-bonded prestressed tendon and concrete according to claim 2, characterized in that, The bond-slip constitutive relationship model includes: Micro-slip section: 0≤s≤s e ; Sliding section: s e ≤ s ≤ s u ; Descending section: s u ≤ s ≤ s r ; Residual segment: s≥s r ; Where τ is the bond stress, s is the bond slip, 0 < α1 ≤ 1, 0 < α2 ≤ 1, w is the bond stress of the residual segment in its local coordinate system, u is the bond slip of the residual segment in its local coordinate system, Δw is the average value of the bond stress amplitudes of all cycles of the residual segment in its local coordinate system, Δu is the average value of the bond slip amplitudes of all cycles of the residual segment in its local coordinate system, and θ is the angle between the local coordinate system where the residual segment is located and the original coordinate system.

4. The calculation method of the bond-slip constitutive relationship between the slow-bonded prestressed tendon and concrete according to claim 2, characterized in that The solving of the characteristic parameters in the bond-slip constitutive relationship model includes: Based on the test data of the bond performance test, fit the correlation between the characteristic parameters and the parameters of the slow-bonded prestressed tendon and concrete to obtain the fitting model of the characteristic parameters.

5. The calculation method of the bond-slip constitutive relationship between the slow-bonded prestressed tendon and concrete according to claim 4, characterized in that, The bond stress τ at the elastic point in the bond stress-bond slip curve e has a fitting model as follows: The bond stress τ at the peak point in the bond stress-bond slip curve u has a fitting model as follows: The bond stress τ of the residual point in the bond stress-bond slip curve r The fitting model is as follows: τ r = k3 × τ u + b3; The bond slip s at the elastic point in the bond stress-bond slip curve e The fitting model is as follows: The bond slip s at the peak point in the bond stress-bond slip curve u has a fitting model as follows: The bond slip s of the residual point in the bond stress-bond slip curve r The fitting model is as follows: s r = b6; Where k1 to k9, b1 to b6, n1 to n6, and m1 to m6 are all fitting constants; d is the diameter of the slow-bonded steel strand, c is the protective layer thickness between the outer edge of the slow-bonded prestressed tendon and the outer edge of the concrete, and L cb is the bonding length between the slow-bonded prestressed tendon and the concrete, and L tb is the length of the slow-bonded prestressed tendon that is not bonded to the concrete, and f is the standard value of the axial compressive strength of the concrete.

6. The calculation method for the bond-slip constitutive relationship between the slow-bonded prestressed tendon and concrete according to claim 5, wherein The bond stress τ at the elastic point in the bond stress-bond slip curve e has a fitting model as follows: The bond stress τ at the peak point in the bond stress-bond slip curve u has a fitting model as follows: The bond stress τ at the residual point in the bond stress-bond slip curve r has a fitting model as follows: τ r = 0.72τ u ; The bond slip s at the elastic point in the bond stress-bond slip curve e has a fitting model as follows: The bond slip s at the peak point in the bond stress-bond slip curve u has a fitting model as follows: The bond slip s at the residual point in the bond stress-bond slip curve r has the following fitting model: s r ＝6.72。 7. The calculation method for the bond-slip constitutive relationship between the slow-bonded prestressed tendon and concrete according to claim 3, characterized in that Convert the bond-slip constitutive relationship model of the residual segment in the local coordinate system to its bond-slip constitutive relationship model in the original coordinate system according to the following formula: u=(s - s r )cosθ-(τ - τ r )sinθ; Δw = Δτcosθ; Δu = Δs / cosθ; Δτ = k 10 × τ u ; Δs = b7; θ = k 11 × τ u ; where k 10 , k 11 and b7 are all fitting constants, Δτ is the average value of the bond stress amplitudes of all cycles of the residual segment in the original coordinate system, and Δs is the average value of the bond slip amplitudes of all cycles of the residual segment in the original coordinate system.

8. A calculation device for the bond-slip constitutive relationship between a slow-bonded prestressed tendon and concrete, characterized in that It includes: A model acquisition module for establishing a bond-slip constitutive relationship model between the slow-bonded prestressed tendon and concrete related to characteristic parameters; A data acquisition module for obtaining the test data of the bond performance test of the slow-bonded prestressed tendon and concrete and drawing the bond stress-bond slip curve based on the test data; A data processing module for solving the characteristic parameters in the bond-slip constitutive relationship model based on the test data and the bond stress-bond slip curve.

9. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the calculation method of the bond-slip constitutive relationship between the slow-bonded prestressed tendon and concrete as described in any one of claims 1 to 8.

10. A computer-readable medium, characterized in that, The computer-readable medium carries computer-executable instructions, which are used to implement the calculation method of the bond-slip constitutive relationship between the slow-bonded prestressed tendon and concrete as described in any one of claims 1 to 8 when executed by the processor.

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