Calculation method for bending stiffness of prefabricated joints, electronic equipment and storage media

Abstract

This invention provides a method, electronic device, and storage medium for calculating the bending stiffness of prefabricated joints. The method includes: acquiring test data from a four-point bending load test on a prefabricated structure, including measured rotation angles in the joint area, rotation error values ​​in the non-joint area, the additional bending moment due to the second-order effect of axial force in the prefabricated structure, and the cracking reduction factor of the concrete in the prefabricated structure; and calculating the bending stiffness of the joints in the prefabricated structure based on the test data. This invention improves the accuracy of calculating the bending stiffness of joints in prefabricated structures.

Description

Technical Field

[0001] This invention relates to the field of railway station assembly technology, and in particular to a method for calculating the bending stiffness of assembled joints, an electronic device, and a storage medium. Background Technology

[0002] Prefabricated structures are concrete structures formed by assembling or connecting prefabricated components, which are the main load-bearing components. Among them, the joints are the weakest points in the entire structure. Therefore, to accurately measure the overall mechanical performance of prefabricated structures, it is necessary to accurately calculate the bending stiffness of the joints.

[0003] In indoor testing, a four-point bending test is typically conducted on a test beam of a certain length with a joint area to simulate the stress conditions of the joint in a prefabricated structure. During the loading process, an opening usually forms in the joint area, and the rotation angle corresponding to this opening is a crucial parameter for calculating the bending stiffness of the joint. In existing technologies, the relative displacement measured by a displacement gauge is typically used as the opening amount of the joint to obtain the corresponding rotation angle. However, the directly measured opening amount is actually the deformation result of the entire prefabricated structure, and there is an error between this measured value and the true value of the joint opening amount. This leads to an error between the calculated bending stiffness of the joint and the actual bending stiffness of the joint, resulting in inaccurate calculations of the bending stiffness of the joint. Summary of the Invention

[0004] This invention provides a method for calculating the bending stiffness of assembled joints, an electronic device, and a storage medium to solve the problem of inaccurate calculation of the bending stiffness of joints in the prior art.

[0005] In a first aspect, embodiments of the present invention provide a method for calculating the bending stiffness of an assembled joint, comprising:

[0006] The test data were obtained when the prefabricated structure was subjected to a four-point bending load test. The test data included the rotation angle measurement value of the joint area in the prefabricated structure, the rotation angle error value generated in the non-joint area, the bending moment addition value of the second-order effect of axial force in the prefabricated structure, and the cracking reduction coefficient of concrete in the prefabricated structure.

[0007] The bending stiffness of the joints in the prefabricated structure was calculated based on the test data.

[0008] In one possible implementation, the method for calculating the angle measurement value of the joint area includes:

[0009] The measurement value of the opening amount of the joint area in the prefabricated structure is obtained by using displacement gauges installed at the junction of the joint area and the non-joint area in the prefabricated structure; wherein, the joint area is the joint-affected area formed around the joint in the prefabricated structure due to the Saint-Venant action, and the area outside the joint area in the prefabricated structure is the non-joint area.

[0010] Calculate the angle measurement value of the joint area based on the measured value of the opening amount in the joint area.

[0011] In one possible implementation, the method for calculating the angular error value generated in the non-joint area includes:

[0012] Obtain the distribution values ​​of the applied load and the structural parameters of the prefabricated structure during the test;

[0013] Based on the structural parameters and the distribution of the applied load during the experiment, the governing equations are established;

[0014] Based on the length of the non-joint area of ​​the prefabricated structure, the control equation is integrated to obtain the angular error value generated by the non-joint area.

[0015] In one possible implementation, the method for calculating the additional bending moment value of the second-order effect of axial force includes:

[0016] Obtain the current axial force of the prefabricated structure and the effective distance from the support to the joint interface of the prefabricated structure during the test;

[0017] According to M add =Nθ test L calculates the additional bending moment due to the second-order effect of axial force in prefabricated structures; where M add θ represents the additional bending moment. test The value represents the measured angle, L represents the effective distance from the support to the joint interface of the prefabricated structure, and N represents the axial force.

[0018] In one possible implementation, the method for calculating the crack reduction factor of concrete in prefabricated structures includes:

[0019] Obtain the material and strain parameters of the prefabricated structure;

[0020] Calculate the reduced stiffness caused by concrete cracking in prefabricated structures based on material and strain parameters.

[0021] Calculate the crack reduction factor of concrete in prefabricated structures based on the reduced stiffness.

[0022] In one possible implementation, the material parameters include the elastic modulus of the steel bars in the prefabricated structure, the cross-sectional area of ​​the steel bars, the effective height of the concrete section in the prefabricated structure, the internal lever arm coefficient of the cracked section in the prefabricated structure, the ratio of the elastic modulus of the steel bars to the elastic modulus of the concrete, the steel reinforcement ratio, the elastic modulus of the prefabricated structure between the test load application location and the support, and the moment of inertia of the prefabricated structure between the test load application location and the support.

[0023] The strain parameters include the strain non-uniformity coefficient of the reinforcing steel and the average strain comprehensive coefficient of the concrete at the edge of the compression zone of the prefabricated structure in the test.

[0024] Based on material and strain parameters, calculate the reduced stiffness caused by concrete cracking in prefabricated structures, including:

[0025] according to Calculate the reduced stiffness caused by concrete cracking in prefabricated structures;

[0026] Based on the reduced stiffness, the cracking reduction factor of concrete in prefabricated structures is calculated, including:

[0027] according to Calculate the crack reduction factor for concrete in prefabricated structures;

[0028] Among them, B t E represents the reduced stiffness. s A represents the elastic modulus of the reinforcing steel. s h0 represents the cross-sectional area of ​​the reinforcing steel, h0 represents the effective height of the concrete section, η represents the internal lever arm coefficient of the cracked section, and α represents the cross-sectional area of ​​the reinforcing steel. E ρ represents the ratio of the elastic modulus of the steel reinforcement to the elastic modulus of the concrete; ψ represents the strain non-uniformity coefficient of the steel reinforcement; ξ represents the average strain coefficient of the concrete at the edge of the compression zone; and k represents the steel reinforcement ratio. s E represents the crack reduction factor. c I represents the elastic modulus of the prefabricated structure between the load application point and the support during the test. b It represents the moment of inertia of the prefabricated structure between the load application point and the support.

[0029] In one possible implementation, the bending stiffness of the joints in the prefabricated structure is calculated based on experimental data, including:

[0030] according to Calculate the bending stiffness of joints in prefabricated structures;

[0031] Among them, K spr θ represents the bending stiffness of the joint in a prefabricated structure. test Represents the measured angle, θ b k represents the angle error value. s M represents the crack reduction factor. test M represents the load applied in the current test. add This represents the additional value of the bending moment.

[0032] Secondly, embodiments of the present invention provide a device for calculating the bending stiffness of an assembled joint, comprising:

[0033] The acquisition module is used to acquire test data when performing a four-point bending load test on the prefabricated structure. The test data includes the measured value of the rotation angle in the joint area of ​​the prefabricated structure, the rotation angle error value generated in the non-joint area, the additional value of the bending moment due to the second-order effect of axial force in the prefabricated structure, and the cracking reduction coefficient of concrete in the prefabricated structure.

[0034] The calculation module is used to calculate the bending stiffness of joints in prefabricated structures based on test data.

[0035] Thirdly, embodiments of the present invention provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described in the first aspect or any possible implementation of the first aspect.

[0036] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the method as described in the first aspect or any possible implementation of the first aspect.

[0037] This invention provides a method, electronic device, and storage medium for calculating the bending stiffness of prefabricated joints. This method calculates the bending stiffness of joints in prefabricated structures by considering the angular error value generated in the non-joint area, the additional bending moment value due to the second-order effect of axial force in the prefabricated structure, and the cracking reduction coefficient of concrete in the prefabricated structure. This method can fully account for errors that may occur during testing of the prefabricated structure. Specifically, the angular error value generated in the non-joint area is considered in actual applications, taking into account the angular value generated by bending and rotation of the non-joint area of ​​the prefabricated structure under load, in order to correct the measured angular value and avoid errors due to neglecting the bending situation in the non-joint area. This addresses the issue of inaccurate calculation of bending stiffness caused by concrete cracking. The additional bending moment value of the second-order effect of axial force in prefabricated structures considers the combined effect of displacement and axial force under horizontal force, resulting in an additional bending moment. The cracking reduction factor for concrete in prefabricated structures considers the cracking situation of concrete, avoiding inaccurate measurement of joint openings due to concrete cracking, which in turn leads to inaccurate calculation of bending stiffness. This approach fully considers the potential causes of errors in calculating joint bending stiffness, avoiding errors caused by directly using the deformation results of the entire prefabricated structure to calculate bending stiffness, thus improving the accuracy of joint bending stiffness calculations in prefabricated structures. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0039] Figure 1 This is a flowchart illustrating the implementation of the method for calculating the bending stiffness of prefabricated joints provided in this embodiment of the invention.

[0040] Figure 2 This is a schematic diagram of the prefabricated structure provided in an embodiment of the present invention undergoing a four-point bending test;

[0041] Figure 3 This is a simplified mechanical diagram of the assembled structure provided in the embodiments of the present invention;

[0042] Figure 4 This is a schematic diagram of the structure of the calculation device for the bending stiffness of the assembled joint provided in an embodiment of the present invention;

[0043] Figure 5 This is a schematic diagram of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0044] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0045] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0046] In indoor tests, bending stiffness is usually used to measure the bending performance of joints in prefabricated structures. Specifically, a four-point bending test is conducted on a test beam of a certain length with a joint area to simulate the stress situation of the joints in the prefabricated structure. Hereinafter, they are all referred to as prefabricated structures.

[0047] During the loading test, an opening usually forms in the joint area. The rotation angle corresponding to this opening is an important parameter for calculating the bending stiffness of the joint. However, the opening amount directly measured by the displacement gauge is actually the deformation result of the entire prefabricated structure. There is an error between this measured value and the true value of the interface opening amount. The inventors considered that the error mainly comes from the following three aspects: first, the error caused by the Euler beam deflection deformation rotation angle generated in the non-joint area of ​​the prefabricated structure; second, the error caused by concrete cracking in the prefabricated structure; and third, the error caused by the second-order effect of axial force (P-Δ effect).

[0048] Based on this, the inventors of this application propose a method for calculating the bending stiffness of prefabricated joints, in order to accurately calculate the bending stiffness of prefabricated structural joints. See also Figure 1 The flowchart illustrating the calculation method for the bending stiffness of the assembled joint provided in this embodiment of the invention is described in detail below:

[0049] Step S101: Obtain test data when performing a four-point bending load test on the prefabricated structure. The test data includes the measured value of the rotation angle in the joint area of ​​the prefabricated structure, the rotation angle error value generated in the non-joint area, the additional value of the bending moment due to the second-order effect of axial force in the prefabricated structure, and the cracking reduction coefficient of concrete in the prefabricated structure.

[0050] Among them, the rotation angle measurement value is directly calculated based on the measured opening amount; the rotation angle error value is obtained by considering the error caused by the Euler beam deflection deformation angle generated in the non-joint area of ​​the prefabricated structure; the bending moment addition value is obtained by considering the error caused by the second-order effect of axial force in the four-point bending test of the prefabricated structure; and the cracking reduction coefficient is obtained by considering the error caused by concrete cracking in the prefabricated structure. By using different test data, the above three error causes can be fully considered, avoiding the error caused by directly using the deformation results of the entire prefabricated structure to calculate the bending stiffness, and improving the calculation accuracy of the bending stiffness of the joints in the prefabricated structure.

[0051] Optional, see Figure 2 The diagram shows a prefabricated structure undergoing a four-point bending test. The circle below the prefabricated structure represents constraints only on the vertical degree of freedom, while the triangle below represents constraints on both the vertical and lateral degrees of freedom. The triangle at the boundary between the joint area and the non-joint area on the prefabricated structure represents a displacement gauge. The calculation method for the joint area's rotation angle measurement is detailed as follows: The displacement gauge, located at the boundary between the joint area and the non-joint area of ​​the prefabricated structure, is used to obtain the measured value of the joint area's opening. The joint area is the joint-affected zone formed around the joint in the prefabricated structure due to the Saint-Venant effect; the area outside the joint area is the non-joint area. Based on the measured value of the joint area's opening, the rotation angle measurement value of the joint area is calculated.

[0052] In this embodiment, the joint area can be defined as the region on both sides of the joint location, which is one beam height distance. This area includes both the location of the joint and the region affected by the joint. Therefore, displacement gauges can be installed at positions on both sides of the joint, one beam height distance, to accurately obtain the measured value of the opening amount in the joint area.

[0053] During the calculation process, the prefabricated structure segments are simplified into beam elements using a beam-spring model. (See [reference]). Figure 3 The mechanical diagram shown is a simplified diagram of the prefabricated structure. Figure 2 The structural schematic diagram shown corresponds to a mechanical abstraction diagram, where the joint is considered as a torsional spring, and the area excluding the joint is considered as an Euler beam or a Timoshenko (Timo) beam. The triangle below the prefabricated structure represents simply supported constraints. The Timo beam is actually a supplementary theory to the Euler beam. The main considerations for choosing between Euler beams and Timo beams are as follows: Generally, the lining thickness of the tunnel should be determined based on the tunnel diameter, tunnel depth, engineering geological and hydrogeological conditions, and the load conditions during the service and construction stages, and should preferably be 0.05 to 0.06 times the outer diameter of the tunnel. Obviously, Euler beams that ignore the shear effect are reasonable in this case. However, when the thickness of the prefabricated structure segments is large, such as when the prefabricated structure is a large-section shield tunnel structure or a prefabricated subway station structure, the shear effect of the beam element cannot be ignored. In this case, Timo beams should be used to calculate the beam rotation angle in the non-joint area to consider the influence of shear action.

[0054] When performing load analysis, torsional springs, Euler beams, and Timo beams will all generate rotation. Since torsional springs have no length, the rotation at the joint should be separated from rotations at other locations in the prefabricated structure during indoor testing. Furthermore, because the non-joint area still conforms to the basic assumptions of beam elements, including the plane section assumption and the assumption that the neutral axis remains at the geometric centroid of the beam, the true rotation result of the joint area can be obtained by removing the rotation results of the non-joint area from the final joint rotation results obtained in the experiment.

[0055] In one possible implementation, the calculation method for the angular error value generated in the non-joint area can be detailed as follows: obtain the distribution value of the applied load in the test and the structural parameters of the prefabricated structure; establish the control equation based on the structural parameters and the distribution value of the applied load in the test; and integrate the control equation based on the length of the non-joint area of ​​the prefabricated structure to obtain the angular error value generated in the non-joint area.

[0056] Optional structural parameters include the elastic modulus of the non-joint area in the prefabricated structure, the moment of inertia of the non-joint area, the load distribution intensity of the non-joint area, the shear stiffness of the non-joint area, the cross-sectional area of ​​the non-joint area, the width of the non-joint area, the height of the non-joint area, and the length of the non-joint area.

[0057] Based on the structural parameters and the distribution of the applied load in the experiment, the governing equations are established, which can be detailed as follows: Based on the structural parameters, we obtain... Where E represents the elastic modulus of the non-joint area in the prefabricated structure, and I represents the moment of inertia of the non-joint area in the prefabricated structure. The rotation angle of the section in the non-joint zone of the prefabricated structure is represented by θ, x represents the variable corresponding to the length of the non-joint zone in the prefabricated structure, q represents the load distribution intensity of the non-joint zone in the test, and θ represents the rotation angle of the section in the non-joint zone in the prefabricated structure. t Let ω represent the angular error value generated in the non-joint area, κ represent the deflection value of the non-joint area in the prefabricated structure, κ represent the Timoshenko coefficient, A represent the cross-sectional area of ​​the non-joint area in the prefabricated structure, and G represent the shear stiffness of the non-joint area in the prefabricated structure. The formula for calculating the moment of inertia of the non-joint area in the prefabricated structure is as follows: b represents the width of the non-joint area in the prefabricated structure, and H represents the height of the non-joint area in the prefabricated structure.

[0058] In this embodiment, the value of EI can be calculated based on the actual materials and measured dimensions of the prefabricated structure. By integrating formula (1) in the control equation, the rotation angle value of the section of the non-joint area in the prefabricated structure can be solved. Substituting this value into formula (2), and finally integrating formula (2) in the control equation, the rotation angle error value generated in the non-joint area can be solved. Timo beam theory is a supplementary theory to Euler beam theory and also considers the shear effect. Therefore, calculating the rotation angle value of the non-joint area using Timo beam theory can fully consider the shear effect and thus accurately calculate the rotation angle error value of the non-joint area.

[0059] In the four-point bending test, as the prefabricated structure bends and deforms, the axial force will generate an additional bending moment on the joint, which will affect the accuracy of the joint's rotation angle measurement. Therefore, the additional bending moment should be considered in the error calculation. In addition, the magnitude of this additional bending moment is affected by the axial force and the joint's rotation angle.

[0060] Optionally, the calculation method for the additional bending moment value of the second-order effect of axial force in prefabricated structures can be detailed as follows: obtain the current axial force of the prefabricated structure and the effective distance from the support to the joint interface of the prefabricated structure during the test; based on M... add =Nθ test L calculates the additional bending moment due to the second-order effect of axial force in prefabricated structures; where M add θ represents the additional bending moment. testThe value represents the measured angle, L represents the effective distance from the support to the joint interface of the prefabricated structure, and N represents the axial force.

[0061] During the loading process of the four-point bending test, the opening does not only occur at the joint position, but cracks and cracks continue to appear and develop in the concrete on the tension side of the entire prefabricated structure; when calculating the rotation error value in the non-joint area, Euler beams or Timo beams should be calculated as beams with cracks, that is, the influence of cracks on the rotation should be considered.

[0062] In one possible implementation, the method for calculating the crack reduction factor of concrete in prefabricated structures can be detailed as follows: obtain the material parameters and strain parameters of the prefabricated structure; calculate the reduced stiffness caused by concrete cracking in the prefabricated structure based on the material parameters and strain parameters; and calculate the crack reduction factor of concrete in the prefabricated structure based on the reduced stiffness.

[0063] Optionally, material parameters include the elastic modulus of the reinforcing steel in the prefabricated structure, the cross-sectional area of ​​the reinforcing steel, the effective height of the concrete section in the prefabricated structure, the internal force arm coefficient of the cracked section in the prefabricated structure, the ratio of the elastic modulus of the reinforcing steel to the elastic modulus of the concrete, the reinforcement ratio of the reinforcing steel, the elastic modulus of the prefabricated structure between the test load application location and the support, and the moment of inertia of the prefabricated structure between the test load application location and the support; strain parameters include the strain non-uniformity coefficient of the reinforcing steel and the average strain comprehensive coefficient of the concrete at the edge of the compression zone of the prefabricated structure in the test.

[0064] Based on material and strain parameters, the reduced stiffness caused by concrete cracking in prefabricated structures is calculated, which can be detailed as follows: Based on Calculate the reduced stiffness caused by concrete cracking in prefabricated structures; based on the reduced stiffness, calculate the cracking reduction factor of concrete in prefabricated structures, which can be detailed as follows: Based on Calculate the crack reduction factor for concrete in prefabricated structures; where B t E represents the reduced stiffness. s A represents the elastic modulus of the reinforcing steel. s h0 represents the cross-sectional area of ​​the reinforcing steel, h0 represents the effective height of the concrete section, η represents the internal lever arm coefficient of the cracked section, and α represents the cross-sectional area of ​​the reinforcing steel. E ρ represents the ratio of the elastic modulus of the steel reinforcement to the elastic modulus of the concrete; ψ represents the strain non-uniformity coefficient of the steel reinforcement; ξ represents the average strain coefficient of the concrete at the edge of the compression zone; and k represents the steel reinforcement ratio. s E represents the crack reduction factor. c I represents the elastic modulus of the prefabricated structure between the load application point and the support during the test. bIt represents the moment of inertia of the prefabricated structure between the load application point and the support.

[0065] In a four-point bending test, pure bending is typically maintained only near the joint, while other locations are subjected to bending and shear forces. In this invention, the crack reduction factor k is calculated at the location of concentrated load application. s Using this crack reduction factor in the bending and shearing areas may lead to an overestimation of the calculated deflection. However, shear deformation also exists in the bending and shearing areas, and even diagonal cracks may appear. If the shear span ratio of the prefabricated structure is designed to be too small, the effect of the overestimation of deflection and the effect of shear deformation can cancel each other out, thus ensuring the accuracy of the final calculation results.

[0066] B t The reduced stiffness caused by concrete cracking in prefabricated structures is mainly derived by calculating the strain of the concrete and steel reinforcement cracked on the tension side of the prefabricated structure, taking into account the uneven strain effect of the steel reinforcement.

[0067] The specific derivation process is as follows:

[0068] Based on mechanics of materials, the formula for calculating stiffness is: Where M represents the external load on the material, The average curvature of the material is used to represent the curvature value, as deflection reflects the comprehensive effect over the span of the beam. Calculate the mean curvature, where, Indicates the strain of the reinforcing steel. h0 represents the concrete strain, and h0 represents the effective height of the concrete section.

[0069] Considering the physical relationships of materials, the moment equilibrium equation for the cross section is established, thus yielding the formula for calculating the strain of the reinforcing steel. The formula for calculating concrete strain is:

[0070] and, This represents the ratio of the elastic modulus of the reinforcing steel to the elastic modulus of the concrete. To represent the reinforcement ratio, substitute the formulas for calculating steel strain and concrete strain into the formula for calculating the average curvature. This will ultimately yield the formula for calculating the reduced stiffness caused by concrete cracking in prefabricated structures.

[0071] Where η represents the internal lever arm coefficient of the cracked section, the statistical results of which are usually between 0.83 and 0.93. A more conservative value can be selected as a reference value based on the statistical range, or a value obtained from actual experimental measurements can be selected. ξ represents the average strain comprehensive coefficient of the concrete at the edge of the compression zone. The value of this average strain comprehensive coefficient is mainly determined based on a large number of experimental results combined with statistical methods. Optionally, the empirical formula for calculating the average strain comprehensive coefficient is as follows: Based on this, the formula for calculating reduced stiffness can be updated to:

[0072] Additionally, ψ represents the strain non-uniformity coefficient of the reinforcing steel. Influenced by bending moment, this coefficient reflects the degree to which the concrete within the cracks participates in tensile stress. As the bending moment increases, the bond strength between cracks gradually weakens, reducing the degree of concrete participation in tensile stress and increasing the average strain. The value of this parameter gradually approaches 1, and correspondingly, the flexural stiffness gradually decreases. Optionally, the formula for calculating the strain non-uniformity coefficient of the reinforcing steel is: Wherein, f tk σ represents the standard tensile strength value of steel reinforcement. sk This represents the ultimate stress of the reinforcing steel; the formula for calculating the ultimate stress of the reinforcing steel is: M u This represents the ultimate load of the prefabricated structure. When ψ < 0.2, ψ takes the value of 0.2; when ψ > 1.0, ψ takes the value of 1.0. In the derivation and calculation process, M can also be set to M... u That is, using the ultimate load of the prefabricated structure, the reduced stiffness caused by concrete cracking in the prefabricated structure is calculated.

[0073] In this embodiment, the combined effects of Euler beam and axial pressure are considered. Although axial pressure plays a beneficial role in suppressing cracking of the beam, its influence on the bending stiffness of the joint often exhibits nonlinear characteristics. There is no consistent conclusion on the quantitative study of this influence. It is generally believed that axial force only serves as a prestress reserve to resist the action of external load in the initial stage of joint cracking. Its mechanism of action in the entire bending process of the joint is not clear. Therefore, the final calculation results in this embodiment may be conservative.

[0074] Step S102: Calculate the bending stiffness of the joints in the prefabricated structure based on the test data.

[0075] Optionally, step S102, which calculates the bending stiffness of the joints in the prefabricated structure based on the test data, can be detailed as follows:

[0076] according to Calculate the bending stiffness of the joints in the prefabricated structure; where K sprθ represents the bending stiffness of the joint in a prefabricated structure. test Represents the measured angle, θ b k represents the angle error value. s M represents the crack reduction factor. test M represents the load applied in the current test. add This represents the additional value of the bending moment.

[0077] In this embodiment, the crack reduction factor applicable to concrete cracks in prefabricated structures is converted into the calculation of the angle error value. The combined error of the crack reduction factor and the angle error value is considered to affect the angle measurement value. The true value of the bending stiffness of the joint is obtained by subtracting the angle measurement value from the combined error.

[0078] In a specific application scenario, the bending stiffness of the joint calculated by this invention can be applied to the torsion spring in the beam-spring calculation model to perform internal force analysis of the overall structure of the beam-spring calculation model. It can also be applied to the shell-spring calculation model or other calculation models. This invention does not limit the specific application scenario of the obtained bending stiffness of the joint.

[0079] This invention calculates the bending stiffness of joints in prefabricated structures by considering the angular error value generated in the non-joint area, the additional bending moment value of the second-order effect of axial force in the prefabricated structure, and the cracking reduction coefficient of concrete in the prefabricated structure. This fully accounts for the errors that may occur during the testing process of the prefabricated structure. The angular error value generated in the non-joint area is taken into account the angular value generated by the bending and rotation of the non-joint area of ​​the prefabricated structure under load in actual applications, in order to correct the measured angular value and avoid inaccurate bending stiffness calculations due to neglecting the bending condition of the non-joint area. The additional bending moment value of the second-order effect of axial force in the prefabricated structure takes into account the effect of the displacement and axial force combination generated by the prefabricated structure under the action of horizontal force, which produces an additional bending moment. The cracking reduction factor of concrete in the prefabricated structure takes into account the cracking situation of concrete in the prefabricated structure, and avoids the problem of inaccurate measurement of joint opening caused by concrete cracking, which leads to inaccurate calculation of bending stiffness. Thus, it can fully take into account the possible causes of error in calculating the bending stiffness of joints, avoid the error caused by directly using the deformation results of the entire prefabricated structure to calculate the bending stiffness, and improve the accuracy and precision of joint bending stiffness calculation in prefabricated structures.

[0080] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0081] The following are device embodiments of the present invention. For details not described in detail, please refer to the corresponding method embodiments described above.

[0082] Figure 4 A schematic diagram of the structure of the calculation device for the bending stiffness of the assembled joint provided in an embodiment of the present invention is shown. For ease of explanation, only the parts related to the embodiment of the present invention are shown, and are described in detail below:

[0083] like Figure 4 As shown, the calculation device 4 for the bending stiffness of the assembled joint includes:

[0084] The acquisition module 41 is used to acquire test data when the prefabricated structure is subjected to a four-point bending load test. The test data includes the rotation angle measurement value of the joint area in the prefabricated structure, the rotation angle error value generated in the non-joint area, the bending moment addition value of the second-order effect of axial force in the prefabricated structure, and the cracking reduction coefficient of concrete in the prefabricated structure.

[0085] The calculation module 42 is used to calculate the bending stiffness of the joints in the prefabricated structure based on the test data.

[0086] In one possible implementation, module 41 is specifically used for:

[0087] The measurement value of the opening amount of the joint area in the prefabricated structure is obtained by using displacement gauges installed at the junction of the joint area and the non-joint area in the prefabricated structure; wherein, the joint area is the joint-affected area formed around the joint in the prefabricated structure due to the Saint-Venant action, and the area outside the joint area in the prefabricated structure is the non-joint area.

[0088] Calculate the angle measurement value of the joint area based on the measured value of the opening amount in the joint area.

[0089] In one possible implementation, module 41 is specifically used for:

[0090] Obtain the distribution values ​​of the applied load and the structural parameters of the prefabricated structure during the test;

[0091] Based on the structural parameters and the distribution of the applied load during the experiment, the governing equations are established;

[0092] Based on the length of the non-joint area of ​​the prefabricated structure, the control equation is integrated to obtain the angular error value generated by the non-joint area.

[0093] In one possible implementation, module 41 is specifically used for:

[0094] Obtain the current axial force of the prefabricated structure and the effective distance from the support to the joint interface of the prefabricated structure during the test;

[0095] According to M add =Nθ testL calculates the additional bending moment due to the second-order effect of axial force in prefabricated structures; where M add θ represents the additional bending moment. test The value represents the measured angle, L represents the effective distance from the support to the joint interface of the prefabricated structure, and N represents the axial force.

[0096] In one possible implementation, module 41 is specifically used for:

[0097] Obtain the material and strain parameters of the prefabricated structure;

[0098] Calculate the reduced stiffness caused by concrete cracking in prefabricated structures based on material and strain parameters.

[0099] Calculate the crack reduction factor of concrete in prefabricated structures based on the reduced stiffness.

[0100] In one possible approach, the material parameters include the elastic modulus of the reinforcing steel in the prefabricated structure, the cross-sectional area of ​​the reinforcing steel, the effective height of the concrete section in the prefabricated structure, the internal lever arm coefficient of the cracked section in the prefabricated structure, the ratio of the elastic modulus of the reinforcing steel to the elastic modulus of the concrete, the reinforcement ratio of the reinforcing steel, the elastic modulus of the prefabricated structure between the test load application location and the support, and the moment of inertia of the prefabricated structure between the test load application location and the support.

[0101] The strain parameters include the strain non-uniformity coefficient of the reinforcing steel and the average strain comprehensive coefficient of the concrete at the edge of the compression zone of the prefabricated structure in the test.

[0102] Module 41 is specifically used for:

[0103] according to Calculate the reduced stiffness caused by concrete cracking in prefabricated structures;

[0104] Module 41 is specifically used for:

[0105] according to Calculate the crack reduction factor for concrete in prefabricated structures;

[0106] Among them, B t E represents the reduced stiffness. s A represents the elastic modulus of the reinforcing steel. s h0 represents the cross-sectional area of ​​the reinforcing steel, h0 represents the effective height of the concrete section, η represents the internal lever arm coefficient of the cracked section, and α represents the cross-sectional area of ​​the reinforcing steel. E ρ represents the ratio of the elastic modulus of the steel reinforcement to the elastic modulus of the concrete; ψ represents the strain non-uniformity coefficient of the steel reinforcement; ξ represents the average strain coefficient of the concrete at the edge of the compression zone; and k represents the steel reinforcement ratio. s E represents the crack reduction factor. cI represents the elastic modulus of the prefabricated structure between the load application point and the support during the test. b It represents the moment of inertia of the prefabricated structure between the load application point and the support.

[0107] In one possible implementation, the computing module 42 is specifically used for:

[0108] according to Calculate the bending stiffness of joints in prefabricated structures;

[0109] Among them, K spr θ represents the bending stiffness of the joint in a prefabricated structure. test Represents the measured angle, θ b k represents the angle error value. s M represents the crack reduction factor. test M represents the load applied in the current test. add This represents the additional value of the bending moment.

[0110] This invention calculates the bending stiffness of joints in prefabricated structures by considering the angular error value generated in the non-joint area, the additional bending moment value of the second-order effect of axial force in the prefabricated structure, and the cracking reduction coefficient of concrete in the prefabricated structure. This fully takes into account the errors that may occur in the prefabricated structure during testing. Among them, the angular error value generated in the non-joint area is to take into account the angular value generated by the bending and rotation of the non-joint area of ​​the prefabricated structure under load in actual applications, so as to correct the measured angular value and avoid the problem of inaccurate bending stiffness calculation due to ignoring the bending of the non-joint area. The additional bending moment value of the second-order effect of axial force in prefabricated structures takes into account the effect of the additional bending moment generated by the combination of displacement and axial force under horizontal force. The cracking reduction factor of concrete in prefabricated structures takes into account the cracking situation of concrete in prefabricated structures, avoiding the problem of inaccurate measurement of joint opening caused by concrete cracking, which leads to inaccurate calculation of bending stiffness. Thus, it can fully consider the possible causes of error in calculating the bending stiffness of joints, avoid the error caused by directly using the deformation results of the entire prefabricated structure to calculate the bending stiffness, and improve the accuracy of joint bending stiffness calculation in prefabricated structures.

[0111] Figure 5 This is a schematic diagram of an electronic device provided in an embodiment of the present invention. For example... Figure 5 As shown, the electronic device 5 in this embodiment includes: a processor 50, a memory 51, and a computer program 52 stored in the memory 51 and executable on the processor 50. When the processor 50 executes the computer program 52, it implements the steps in the above embodiments of the calculation method for the bending stiffness of the assembled joints, for example... Figure 1Steps S101 to S102 are shown. Alternatively, when the processor 50 executes the computer program 52, it implements the functions of each module in the above-described device embodiments, for example... Figure 4 The functions of modules 41 to 42 are shown.

[0112] For example, the computer program 52 can be divided into one or more modules / units, which are stored in the memory 51 and executed by the processor 50 to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 52 in the electronic device 5. For example, the computer program 52 can be divided into... Figure 4 Modules 41 to 42 are shown.

[0113] The electronic device 5 may include, but is not limited to, a processor 50 and a memory 51. Those skilled in the art will understand that... Figure 5 This is merely an example of electronic device 5 and does not constitute a limitation on electronic device 5. It may include more or fewer components than shown, or combine certain components, or different components. For example, the electronic device may also include input / output devices, network access devices, buses, etc.

[0114] The processor 50 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0115] The memory 51 can be an internal storage unit of the electronic device 5, such as a hard disk or memory. The memory 51 can also be an external storage device of the electronic device 5, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card. Furthermore, the memory 51 can include both internal and external storage units of the electronic device 5. The memory 51 is used to store the computer program and other programs and data required by the electronic device. The memory 51 can also be used to temporarily store data that has been output or will be output.

[0116] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0117] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0118] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0119] In the embodiments provided by this invention, it should be understood that the disclosed devices / electronic devices and methods can be implemented in other ways. For example, the device / electronic device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0120] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0121] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0122] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0123] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method of calculating the bending stiffness of a fabricated joint, characterized in that, The method comprises the following steps: obtaining test data of a four-point bending test of the fabricated structure, the test data comprising a joint area rotation measurement value of the fabricated structure, a non-joint area rotation error value generated by the fabricated structure, a bending moment additional value of a second-order effect of an axial force in the fabricated structure, and a cracking reduction factor of concrete in the fabricated structure; calculating the bending stiffness of the joint in the fabricated structure according to the test data; the method for calculating the cracking reduction factor of concrete in the fabricated structure comprises: obtaining material parameters and strain parameters of the fabricated structure; calculating the reduction stiffness caused by concrete cracking in the fabricated structure according to the material parameters and the strain parameters; calculating the cracking reduction factor of concrete in the fabricated structure according to the reduction stiffness; the material parameters comprise the elastic modulus of the steel bar in the fabricated structure, the cross-sectional area of the steel bar, the effective height of the cross section of the concrete in the fabricated structure, the internal force arm coefficient of the cracking cross section in the fabricated structure, the ratio of the elastic modulus of the steel bar to the elastic modulus of the concrete, the steel reinforcement ratio, the elastic modulus of the fabricated structure between the test load position and the support, and the cross-sectional moment of inertia of the fabricated structure between the test load position and the support; the strain parameters comprise the strain inhomogeneity coefficient of the steel bar and the average strain comprehensive coefficient of the concrete at the edge of the compression zone in the test of the fabricated structure; calculating the reduction stiffness caused by concrete cracking in the fabricated structure according to the material parameters and the strain parameters comprises: According to , the reduced stiffness caused by concrete cracking in the fabricated structure is calculated; calculating the cracking reduction factor of concrete in the fabricated structure according to the reduction stiffness comprises: According to , the cracking reduction factor of the concrete in the fabricated structure is calculated; wherein, denotes the cracking stiffness, denotes the elastic modulus of the reinforcement, denotes the cross-sectional area of the reinforcement, denotes the effective height of the cross-section of the concrete, denotes the internal force arm coefficient of the cracking cross-section, denotes the ratio of the elastic modulus of the reinforcement to the elastic modulus of the concrete, denotes the reinforcement ratio of the reinforcement, denotes the strain inhomogeneity coefficient of the reinforcement, denotes the average strain comprehensive coefficient of the concrete at the edge of the compression zone, denotes the cracking reduction coefficient, denotes the elastic modulus of the fabricated structure between the test loading load action position and the support, denotes the cross-sectional moment of inertia of the fabricated structure between the test loading load action position and the support; calculating the bending stiffness of the joint in the fabricated structure according to the test data comprises: According to , the bending stiffness of the joint in the fabricated structure is calculated; wherein, represents the bending stiffness of the joint in the fabricated structure, represents the measured value of the rotation angle, represents the error value of the rotation angle, represents the cracking reduction factor, represents the load in the current test, represents the bending moment addition value.

2. The method for calculating the flexural rigidity of a fabricated joint according to claim 1, characterized in that, the method for calculating the joint area rotation measurement value comprises: obtaining the measurement value of the opening amount of the joint area in the fabricated structure through a displacement meter arranged at the joint area and the non-joint area of the fabricated structure; wherein the joint area is the joint influence area formed around the joint in the fabricated structure due to the Saint-Venant effect, and the area outside the joint area in the fabricated structure is the non-joint area; calculating the joint area rotation measurement value according to the measurement value of the opening amount of the joint area.

3. The method of calculating the flexural rigidity of a fabricated joint according to claim 1, wherein, the method for calculating the non-joint area rotation error value comprises: obtaining the distribution value of the loading load in the test and the structural parameters of the fabricated structure; establishing a control equation according to the structural parameters and the distribution value of the loading load in the test; integrating the control equation according to the length of the non-joint area of the fabricated structure to obtain the non-joint area rotation error value.

4. The method of calculating the flexural rigidity of a fabricated joint according to claim 1, wherein, the method for calculating the bending moment additional value of the second-order effect of the axial force comprises: obtaining the current axial force of the fabricated structure and the effective distance from the support to the joint interface of the fabricated structure in the test; According to a bending moment additional value of a second order effect of an axial force in the fabricated structure is calculated; wherein, denotes the bending moment additional value, denotes the rotation angle measurement value, denotes an effective distance of a joint interface of a support to the fabricated structure, denotes the axial force.

5. A device for calculating the bending stiffness of a fabricated joint, characterized in that the method comprises the following steps: An acquisition module is configured to acquire test data of a four-point bending test of an assembled structure, the test data including a joint area rotation measurement value, a non-joint area rotation error value, a bending moment additional value of a second-order effect of an axial force in the assembled structure, and a cracking reduction coefficient of concrete in the assembled structure. A calculation module is configured to calculate a bending stiffness of a joint in the assembled structure according to the test data. The acquisition module is specifically configured to: acquire material parameters and strain parameters of the assembled structure; calculate a reduction stiffness caused by concrete cracking in the assembled structure according to the material parameters and the strain parameters; calculate the cracking reduction coefficient of the concrete in the assembled structure according to the reduction stiffness; The material parameters include an elastic modulus of a steel bar in the assembled structure, a cross-sectional area of the steel bar, an effective height of a cross section of concrete in the assembled structure, an internal force arm coefficient of a cracking cross section in the assembled structure, a ratio of the elastic modulus of the steel bar to the elastic modulus of the concrete, a steel reinforcement ratio, an elastic modulus of the assembled structure between a test load position and a support, and a cross-sectional moment of inertia of the assembled structure between the test load position and the support. The strain parameters include a strain inhomogeneity coefficient of the steel bar and an average strain comprehensive coefficient of concrete at an edge of a compression zone in the test of the assembled structure. The acquisition module is specifically configured to: According to , the reduced stiffness caused by concrete cracking in the fabricated structure is calculated; The acquisition module is specifically configured to: According to , the cracking reduction factor of the concrete in the fabricated structure is calculated; wherein, denotes the reduction stiffness, denotes the elastic modulus of the reinforcement, denotes the cross-sectional area of the reinforcement, denotes the effective height of the cross-section of the concrete, denotes the internal force arm coefficient of the cracked cross-section, denotes the ratio of the elastic modulus of the reinforcement to the elastic modulus of the concrete, denotes the reinforcement ratio of the reinforcement, denotes the strain inhomogeneity coefficient of the reinforcement, denotes the average strain comprehensive coefficient of the concrete at the edge of the compression zone, denotes the cracking reduction coefficient, denotes the elastic modulus of the fabricated structure between the test loading load action position and the support, denotes the cross-sectional moment of inertia of the fabricated structure between the test loading load action position and the support; The calculation module is specifically configured to: According to , the bending stiffness of the joints in the fabricated structure is calculated; wherein, represents the bending stiffness of the joint in the fabricated structure, represents the measured value of the rotation angle, represents the error value of the rotation angle, represents the cracking reduction factor, represents the load in the current test, represents the bending moment addition value.

6. An electronic device comprising a memory for storing a computer program and a processor for invoking and running the computer program stored in the memory, characterized in that, The processor executes the computer program to implement the steps of the method of any one of claims 1 to 4.

7. A computer-readable storage medium storing a computer program, wherein the computer program comprises the following steps of: receiving a request for a resource from a client; determining whether the client is authorized to access the resource; and if the client is authorized to access the resource, providing the resource to the client. The computer program is executed by the processor to implement the steps of the method of any one of claims 1 to 4.

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