Method, device, equipment and medium for performance evaluation of prestressed concrete member

Abstract

This application relates to a method, apparatus, device, and medium for performance evaluation of prestressed concrete members. The method includes: determining a first net effective moment of inertia of the cross-section of each section in the prestressed concrete member based on the first effective moment of inertia of the concrete at the current moment and the moment of inertia of the non-prestressed tendons of the cross-section; determining the concrete stress at the centroid of the prestressed tendons of the cross-section based on the first net effective moment of inertia of the cross-section and the currently applied bending moment of the cross-section; determining the prestress loss caused by concrete shrinkage and creep based on the concrete stress of each cross-section, the shrinkage strain parameters of the prestressed concrete member, and a first creep coefficient; determining the total prestress loss of the prestressed concrete member based on the prestress loss caused by concrete shrinkage and creep; the total prestress loss is used to characterize the prestressing performance of the prestressed concrete member. This method can improve the accuracy of the evaluation of the total prestress loss.

Description

Technical Field

[0001] This application relates to the field of bridge and structural engineering technology, and in particular to a method, apparatus, equipment and medium for performance evaluation of prestressed concrete components. Background Technology

[0002] Long-term prestress loss refers to the gradual decrease in effective stress in the prestressing tendons of a prestressed concrete member over time due to concrete shrinkage, creep, and prestressing tendon relaxation. The long-term performance and safety of prestressed concrete members depend on the effective prestress remaining in the reinforcement after various losses. Therefore, a total prestress loss assessment of prestressed concrete members is necessary to ensure their reliability.

[0003] In related technologies, the prestressed performance of prestressed concrete members is often evaluated based on standards or empirical models under the assumption that "the cross-section is not cracked or is equivalently simplified to be cracked". However, this method suffers from low evaluation accuracy when evaluating the performance of some prestressed concrete members or concrete members that are allowed to crack. Summary of the Invention

[0004] Therefore, it is necessary to provide a performance evaluation method, apparatus, equipment, and medium for prestressed concrete members that can improve the evaluation accuracy of total prestress loss, in order to address the aforementioned technical problems.

[0005] In a first aspect, this application provides a method for performance evaluation of prestressed concrete members, including:

[0006] The first net effective moment of inertia of the prestressed concrete member is determined based on the first effective moment of inertia of the concrete at the current moment and the moment of inertia of the non-prestressed tendons of the section; wherein the first effective moment of inertia of the concrete is determined based on the current cracking state information of the section and the cracking state information in the historical period.

[0007] Based on the effective moment of inertia of the first net section of the cross section and the currently applied bending moment of the cross section, determine the concrete stress at the centroid of the prestressing tendons of the cross section;

[0008] Based on the concrete stress at each section, the shrinkage strain parameter of the prestressed concrete member, and the first creep coefficient, the prestress loss caused by concrete shrinkage and creep is determined; wherein, the shrinkage strain parameter characterizes the cumulative shrinkage strain of the concrete in the prestressed concrete member during the historical period, and the first creep coefficient characterizes the creep of the concrete during the historical period.

[0009] The total prestress loss of the prestressed concrete member is determined based on the prestress loss caused by concrete shrinkage and creep; the total prestress loss is used to characterize the prestress performance of the prestressed concrete member.

[0010] In one embodiment, the determination of the effective moment of inertia of the first concrete includes:

[0011] If the current applied bending moment at the cross section is less than the initial cracking bending moment at the cross section, and the cross section has not cracked during the historical period, the first effective concrete moment of inertia of the cross section is determined based on the gross moment of inertia of the cross section.

[0012] If the current applied bending moment at the cross section is less than the initial cracking bending moment at the cross section, and the cross section has cracked during the historical period, the first effective concrete moment of inertia of the cross section is determined based on the cracked section moment of inertia, the initial cracking bending moment, the historical maximum bending moment, and the gross section moment of inertia.

[0013] If the current applied bending moment of the cross section is greater than or equal to the initial cracking bending moment of the cross section, and the cross section has cracked during the historical period, the first effective concrete moment of inertia of the cross section is determined based on the moment of inertia of the cracked cross section, the initial cracking bending moment, the current applied bending moment, and the gross cross section moment of inertia.

[0014] In one embodiment, determining the prestress loss caused by concrete shrinkage and creep based on the concrete stress at each cross-section, the shrinkage strain parameter of the prestressed concrete member, and the first creep coefficient includes: determining the average concrete stress based on the concrete stress at each cross-section; and determining the prestress loss caused by concrete shrinkage and creep based on the average concrete stress, the shrinkage strain parameter, and the first creep coefficient.

[0015] In one embodiment, the method further includes: determining a second net effective moment of inertia of the cross section based on the second effective moment of inertia of the concrete at the loading age and the moment of inertia of the non-prestressed tendons for each cross section in the prestressed concrete member; determining a first damage degree factor of the cross section based on the second net effective moment of inertia of the cross section; the first damage degree factor being used to characterize the degree of stiffness degradation of the cross section due to concrete cracking; determining the long-term deflection of the prestressed concrete member based on the second creep coefficient of the prestressed concrete member from the loading age to the current time and the first damage degree factor of each cross section; the long-term deflection being used to characterize the deflection performance of the prestressed concrete member.

[0016] In one embodiment, determining the long-term deflection of the prestressed concrete member based on a second creep coefficient from the loading age to the current time and a first damage factor for each of the cross sections includes: determining a theoretical damage factor for the prestressed concrete member based on the first damage factor for each of the cross sections; determining a long-term deflection growth coefficient for the prestressed concrete member based on the second creep coefficient and the theoretical damage factor; and determining the long-term deflection based on the long-term deflection growth coefficient and the initial deflection of the prestressed concrete member.

[0017] In one embodiment, determining the long-term deflection growth coefficient of the prestressed concrete member based on the second creep coefficient and the theoretical damage factor includes: obtaining the horizontal strain values ​​at each analysis point within a preset area of ​​the prestressed concrete member; determining the measured damage factor of the prestressed concrete member based on each horizontal strain value; updating the theoretical damage factor according to the measured damage factor when the relative deviation between the measured damage factor and the theoretical damage factor is greater than a preset deviation threshold, to obtain an updated damage factor; and determining the long-term deflection growth coefficient based on the second creep coefficient and the updated damage factor.

[0018] In one embodiment, determining the measured damage degree factor of the prestressed concrete member based on each of the horizontal strain values ​​includes: determining a first average level strain value for all the horizontal strain values; sorting the horizontal strain values ​​in descending order and determining a second average level strain value for the first preset number of horizontal strain values; and determining the measured damage degree factor based on the first average level strain value and the second average level strain value.

[0019] Secondly, this application also provides a performance evaluation device for prestressed concrete members, comprising:

[0020] The first determining module is used to determine the first net effective moment of inertia of the prestressed concrete member based on the first effective moment of inertia of the concrete at the current moment and the non-prestressed tendon moment of inertia of the section; wherein the first effective moment of inertia of the concrete is determined based on the current cracking state information of the section and the cracking state information in the historical period.

[0021] The second determining module is used to determine the concrete stress at the centroid of the prestressing tendons of the cross section based on the effective moment of inertia of the first net cross section and the current applied bending moment of the cross section.

[0022] The third determining module is used to determine the prestress loss caused by concrete shrinkage and creep based on the concrete stress of each section, the shrinkage strain parameter of the prestressed concrete member, and the first creep coefficient; wherein the shrinkage strain parameter characterizes the cumulative shrinkage strain of the concrete in the prestressed concrete member during the historical period, and the first creep coefficient characterizes the creep of the concrete during the historical period.

[0023] The fourth determining module is used to determine the total prestress loss of the prestressed concrete member based on the prestress loss caused by concrete shrinkage and creep; the total prestress loss is used to characterize the prestress performance of the prestressed concrete member.

[0024] Thirdly, this application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the performance evaluation method for prestressed concrete members provided in the first aspect of this application.

[0025] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the performance evaluation method for prestressed concrete members provided in the first aspect of this application.

[0026] Fifthly, this application also provides a computer program product, including a computer program that, when executed by a processor, implements the performance evaluation method for prestressed concrete members provided in the first aspect of this application.

[0027] The aforementioned performance evaluation method, apparatus, computer equipment, computer-readable storage medium, and computer program product for prestressed concrete members determine the first net section effective moment of inertia based on the first effective moment of inertia of the concrete and the non-prestressed tendon moment of inertia of the prestressed concrete member at the current moment. The first effective moment of inertia of the concrete is determined based on the current cracking state information and cracking state information over a historical period of the prestressed concrete member. Based on the first net section effective moment of inertia and the currently applied bending moment at each section of the prestressed concrete member, the concrete stress at the centroid of the prestressed tendon at each section is determined. Based on each concrete stress, shrinkage strain parameter, and first creep coefficient, the prestress loss caused by concrete shrinkage and creep is determined. The shrinkage strain parameter characterizes the cumulative shrinkage strain of the concrete in the prestressed concrete member over a historical period, and the first creep coefficient characterizes the creep of the concrete over a historical period. The total prestress loss of the prestressed concrete member is determined based on the prestress loss. The total prestress loss is used to characterize the prestressing performance of the prestressed concrete member. As can be seen, the first effective moment of inertia of concrete in this embodiment is determined based on the current cracking state information of the component and the cracking state information in the historical period, taking into account the actual cracking situation of the component. Therefore, the prestress loss caused by concrete shrinkage and creep determined based on the first effective moment of inertia of concrete takes into account the actual cracking situation of the component, and can accurately reflect the influence of the actual cracking situation of the component on the prestress loss caused by concrete shrinkage and creep. Therefore, it can improve the evaluation accuracy of prestress loss caused by concrete shrinkage and creep, and thus improve the evaluation accuracy of the total prestress loss of the component. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a diagram illustrating the application environment of a performance evaluation method for prestressed concrete members in one embodiment.

[0030] Figure 2 This is a flowchart illustrating a performance evaluation method for prestressed concrete members in one embodiment.

[0031] Figure 3 This is a structural schematic diagram of a prestressed concrete beam in one embodiment;

[0032] Figure 4 This is a schematic diagram showing the installation location of the force sensor in one embodiment;

[0033] Figure 5 This is a flowchart illustrating the performance evaluation method for prestressed concrete members in another embodiment;

[0034] Figure 6 This is a schematic diagram of the process for determining the long-term deflection growth factor in one embodiment;

[0035] Figure 7 This is a schematic diagram of a high-speed camera deployment in one embodiment;

[0036] Figure 8 This is a structural block diagram of a performance evaluation device for prestressed concrete members in one embodiment.

[0037] Figure 9 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0039] It should be noted that the terms "first," "second," etc., used in this application can be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from the second element. The terms "comprising" and "having," and any variations thereof, used in this application, are intended to cover non-exclusive inclusion. The term "multiple" used in this application refers to two or more. The term "and / or" used in this application refers to one of the embodiments, or any combination of multiple embodiments.

[0040] In the field of long-term performance evaluation and health monitoring of prestressed concrete components in bridge and structural engineering, there are generally two approaches:

[0041] (1) Calculation method for long-term prestress loss of prestressed concrete members: Usually, according to the design code / guideline for bridge or concrete structure, the prestress loss is estimated according to "prestress loss caused by relaxation of steel strands and prestress loss caused by concrete shrinkage and creep (and other optional items)". This type of method can output the loss of each item and the total loss, and can be used for long-term prediction of the effective prestress level. However, this type of method is usually based on simplified stress state assumptions of the section, which makes it difficult to reflect the change of the neutral axis position, the degradation of the effective moment of inertia and the spatiotemporal change of the concrete stress at the centroid of the prestressing tendon after cracking occurs during the long-term load-bearing process, thus there is a deviation in the prediction of the shrinkage-creep type loss component of cracked members;

[0042] (2) Equivalent stiffness method for predicting long-term deflection of cracked prestressed concrete members: The effective moment of inertia or piecewise stiffness reduction method is often used, combined with the idea of ​​adjusting the elastic modulus by creep coefficient / age to estimate the long-term deflection growth. This type of method can describe the effect of stiffness reduction caused by cracking on instantaneous deflection, but does not consider the effect of cracking / damage on long-term deflection.

[0043] It is evident that the relevant technologies have the following problems:

[0044] (1) Insufficient consideration of cracking effect of prestressed members: Long-term prestress loss prediction often fails to incorporate "degradation of effective moment of inertia caused by cracking, change of neutral axis position, and change of spatial distribution of concrete stress at the centroid of prestressed steel bars" into a closed-loop iterative process, resulting in large deviation in the long-term loss prediction of cracked prestressed members.

[0045] (2) Lack of verification mechanism: The long-term prestress loss prediction model and deflection prediction model lack verification and correction mechanism based on measured crack / damage results, resulting in insufficient model usability and engineering credibility.

[0046] Therefore, related technologies lack an integrated coupled process for "prestress loss decomposition—damage assessment—long-term deflection prediction" for cracked prestressed members, as well as a data-driven verification / correction mechanism. A closed-loop evaluation method for cracked prestressed members is needed to achieve consistent calculation of "prestress loss decomposition calculation and long-term deflection prediction" within a unified framework, and to support verification and deviation-driven correction using monitoring data. To this end, this application provides a performance evaluation method for prestressed concrete members. With the support of a multi-source monitoring system, a coupled calculation process is constructed for "prestress loss assessment, damage degree factor determination, and long-term deflection growth coefficient assessment." Simultaneously, crack / damage identification based on Digital Image Correlation (DIC) is introduced to verify theoretical damage and crack development, and to correct the damage degree factor when the deviation is large, thereby improving the accuracy of long-term prediction and the reliability of early warning.

[0047] The performance evaluation method for prestressed concrete members provided in this application embodiment can be applied to, for example... Figure 1 In the application environment shown, terminal 102 communicates with server 104 via a network. A data storage system can store the data that server 104 needs to process. The data storage system can be integrated onto server 104, or it can be located in the cloud or on other network servers. Terminal 102 can be, but is not limited to, various personal computers, laptops, smartphones, and tablets. Server 104 can be a standalone physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing cloud computing services.

[0048] This application's embodiments use "degradation of effective moment of inertia caused by cracking" as an example. Using "" as the key variable, a calculation chain is constructed that includes "prestress loss assessment, damage degree factor analysis, deflection growth coefficient calculation, and long-term deflection prediction". The DIC crack identification is used to correct the damage and deflection prediction results, so as to achieve an integrated assessment of loss, damage and deflection.

[0049] In one exemplary embodiment, such as Figure 2 As shown, a performance evaluation method for prestressed concrete members is provided, which can be applied to... Figure 1 Taking the server in the example, the explanation includes the following steps 201 to 204. Wherein:

[0050] Step 201: Determine the first net effective moment of inertia of the section based on the first effective moment of inertia of the concrete and the non-prestressed tendon of each section in the prestressed concrete member at the current moment.

[0051] In this context, a cross-section refers to the planar shape obtained by cutting the prestressed concrete member perpendicular to its length direction (i.e., the span direction). Different positions along the span direction (e.g., mid-span, quarter-span, supports, etc.) correspond to different cross-sections, each with independent cracking states, stress distributions, and stiffness characteristics. The first effective concrete moment of inertia is determined based on the current cracking state information of the cross-section and cracking state information over historical periods. The first effective concrete moment of inertia characterizes the contribution of the concrete portion of the cross-section to the moment of inertia at the current moment. The non-prestressed tendon moment of inertia characterizes the contribution of all non-prestressed steel bars in the cross-section to the moment of inertia; this value is a constant and can be calculated by converting the area of ​​the non-prestressed steel bars into the equivalent concrete area according to the elastic modulus ratio. The first net section effective moment of inertia characterizes the net effective flexural stiffness of the cross-section at the current moment.

[0052] For example, firstly, the current cracking state information (e.g., whether the member is in a cracked state at the current time t) and the cracking state information within a historical period (e.g., whether the member has cracked within a historical period) of each section in the prestressed concrete member are determined, where the historical period refers to the period from the tensioning age t0 to the current time t; then, based on the current cracking state information and the cracking state information within the historical period of each section, the first effective concrete moment of inertia of that section is determined; finally, based on the first effective concrete moment of inertia and the non-prestressed tendon moment of inertia of each section, the first net effective moment of inertia of that section is determined.

[0053] Optionally, the first net effective moment of inertia of the cross section at the current time t can be calculated using the following formula. :

[0054] (1)

[0055] Among them, among them, Let be the first effective moment of inertia of the concrete section at the current time t. Changes with cracking state / time; Let be the moment of inertia of the cross section at the current time t, excluding prestressed tendons.

[0056] Step 202: Determine the concrete stress at the centroid of the prestressing tendons of the section based on the effective moment of inertia of the first net section and the current applied bending moment of the section.

[0057] The currently applied bending moment refers to the bending moment value generated on the cross-section of the member by the external load at the current time t. Optionally, the currently applied bending moment can be obtained through actual measurement, theoretical calculation, etc. The concrete stress at the centroid of the prestressing tendons in the cross-section refers to the normal stress borne by the concrete at the location of the point of application of the resultant force of all prestressing tendons on the cross-section (i.e., the centroid of the prestressing tendons).

[0058] For example, for each section of the member along the span direction, the bending stress generated by the eccentricity of the prestressing resultant force is first determined based on the effective moment of inertia of the first net section, and the bending stress of the external load is determined based on the currently applied bending moment of the section; then, the concrete stress at the centroid of the prestressing tendon of the section is determined according to the stress generated by the effective tensile force of the prestressing tendon, the bending stress generated by the eccentricity of the prestressing resultant force, and the bending stress of the external load.

[0059] Alternatively, the concrete stress at the centroid of the prestressing tendons in the section can be calculated using the following formula:

[0060] (2)

[0061] Where z is the horizontal coordinate along the beam span, z∈(0,L), and L is the total length of the prestressed concrete member. Let Z be the concrete stress at the centroid of the prestressing tendon at the section at position z at the current time t. The resultant force (effective tensile force) of the prestressed tendons in the prestressed concrete member at the current moment can be obtained by actual measurement using a force sensor; The net cross-sectional area of ​​the section (i.e., the converted cross-sectional area minus the cross-sectional area of ​​all prestressed tendons converted into concrete, in mm). 2 ), y is the eccentricity of the resultant force of the prestressing tendons (in mm); y is the distance between the centroid of the net section and the centroid of the prestressing tendons (in mm). The effective moment of inertia of the cross section at the current time t (unit: mm) is the first net cross section moment. 4 ); Let be the bending moment (in N·m) generated by the external load at position z and current time t. In this formula:

[0062] , , These are the stress generated by the effective tensile force of the prestressing tendons, the bending stress generated by the eccentricity of the prestressing resultant force, and the bending stress caused by the external load, respectively.

[0063] by Figure 3 The multi-source data monitoring system of this application is illustrated using a prestressed concrete beam as an example. Figure 3 The stress state of prestressed concrete beams under actual service conditions was simulated, such as... Figure 3 As shown, a prestressed concrete beam is placed on two rigid supports. Prestressing (steel) tendons are installed inside the beam to apply prestress to control cracking and deformation. Figure 4 As shown, a force sensor is installed at the end of the prestressing tendon to measure the tensile force N of the prestressing tendon in real time. P (t).

[0064] Step 203: Based on the concrete stress of each section, the shrinkage strain parameters of the prestressed concrete member, and the first creep coefficient, determine the prestress loss caused by concrete shrinkage and creep.

[0065] Among them, the shrinkage strain parameter characterizes the cumulative shrinkage strain of concrete in prestressed concrete members over a historical period, and the first creep coefficient characterizes the creep of concrete over a historical period. The historical period refers to the time between the tensioning age t0 and the current time t.

[0066] For example, after obtaining the concrete stress at the centroid of the prestressing tendons in all sections, the prestress loss caused by concrete shrinkage is first determined based on the elastic modulus of the prestressing tendons and the shrinkage strain parameters from the tensioning age t0 to the current time t. Then, the prestress loss caused by concrete creep is determined based on the ratio of the elastic modulus of the prestressing tendons to that of the concrete, the stresses in each concrete section, and the first creep coefficient from the tensioning age t0 to the current time t. Finally, based on the prestress loss caused by concrete shrinkage and the prestress loss caused by concrete creep, the prestress loss caused by both concrete shrinkage and creep is determined.

[0067] Step 204: Determine the total prestress loss of the prestressed concrete member based on the prestress loss caused by concrete shrinkage and creep; the total prestress loss is used to characterize the prestress performance of the prestressed concrete member.

[0068] For example, first, the prestress loss caused by prestressing tendon relaxation is determined. Then, based on the sum of the prestress loss caused by prestressing tendon relaxation and the prestress loss caused by concrete shrinkage and creep obtained in step 203, the total prestress loss of the prestressed concrete member is obtained. Optionally, the formula for calculating the prestress loss caused by prestressing tendon relaxation is:

[0069] (3)

[0070] Where, σ l5 ζ represents the prestress loss caused by the relaxation of prestressing tendons; ψ is the over-tensioning coefficient, taken as 0.9 for over-tensioning and 1.0 for no over-tensioning; ζ σ is the relaxation coefficient of the prestressing material; 0.3 is used for low-relaxation prestressing tendons, and 1.0 is used for ordinary prestressing tendons; pe f is the initial tensile stress of the prestressing tendon; ptk This represents the ultimate tensile strength of the prestressed tendons.

[0071] The formula for calculating the total prestress loss is:

[0072] (4)

[0073] in, This represents the total prestress loss of the prestressed concrete member from the tensioning age to the current time t. This represents the prestress loss caused by concrete shrinkage and creep at the current time t.

[0074] In the aforementioned performance evaluation method for prestressed concrete members, the effective moment of inertia of the first net section is determined based on the first effective moment of inertia of the concrete and the moment of inertia of the non-prestressed tendons at the current moment. The first effective moment of inertia of the concrete is determined based on the current cracking state information and the cracking state information over a historical period of the prestressed concrete member. Based on the first effective moment of inertia of the net section and the currently applied bending moment of each section in the prestressed concrete member, the concrete stress at the centroid of the prestressed tendons at each section is determined. Based on each concrete stress, shrinkage strain parameter, and first creep coefficient, the prestress loss caused by concrete shrinkage and creep is determined. The shrinkage strain parameter characterizes the cumulative shrinkage strain of the concrete in the prestressed concrete member over a historical period, and the first creep coefficient characterizes the creep of the concrete over a historical period. The total prestress loss of the prestressed concrete member is determined based on the prestress loss. The total prestress loss is used to characterize the prestressing performance of the prestressed concrete member. As can be seen, the first effective moment of inertia of concrete in this embodiment is determined based on the current cracking state information of the component and the cracking state information in the historical period, taking into account the actual cracking situation of the component. Therefore, the prestress loss caused by concrete shrinkage and creep determined based on the first effective moment of inertia of concrete takes into account the actual cracking situation of the component, and can accurately reflect the influence of the actual cracking situation of the component on the prestress loss caused by concrete shrinkage and creep. Therefore, it can improve the evaluation accuracy of prestress loss caused by concrete shrinkage and creep, and thus improve the evaluation accuracy of the total prestress loss of the component.

[0075] In an exemplary embodiment, the determination of the first effective moment of inertia of concrete includes: determining the first effective moment of inertia of the cross-section based on the gross moment of inertia of the cross-section when the current applied bending moment of the cross-section is less than the initial cracking bending moment of the cross-section and the cross-section has not cracked during the historical period; determining the first effective moment of inertia of the cross-section based on the cracked section moment of inertia, the initial cracking bending moment, the historical maximum bending moment, and the gross moment of inertia when the current applied bending moment of the cross-section is greater than or equal to the initial cracking bending moment of the cross-section and the cross-section has cracked during the historical period; and determining the first effective moment of inertia of the cross-section based on the cracked section moment of inertia, the initial cracking bending moment, the current applied bending moment, and the gross moment of inertia when the current applied bending moment of the cross-section is greater than or equal to the initial cracking bending moment of the cross-section and the cross-section has cracked during the historical period.

[0076] For example, the first effective moment of inertia of the concrete section is calculated using the following formula:

[0077] (5)

[0078] Among them, I g The moment of inertia (i.e., gross moment of inertia) of the uncracked (concrete) section about the centroidal axis; I crThe moment of inertia of the cracked section (i.e., the moment of inertia of the cracked section) can be calculated according to Appendix J of the "Design Specification for Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts (JTG 3362—2018)"; M a The current applied bending moment for the section; M cr M is the initial cracking moment of the cross section; max This represents the maximum bending moment experienced by the section during its previous loading process (i.e., the historical maximum bending moment).

[0079] Alternatively, the initial cracking moment of the section can be calculated using the following formula:

[0080] (6)

[0081] in, The plastic influence coefficient of the concrete section modulus is γ = 2S0 / W0, where S0 is the static moment (mm) of the transformed section about the neutral axis and about the tension edge. 3 W0 is the elastic modulus of the tension edge of the equivalent section (mm). 3 ); This represents the measured tensile strength of concrete (MPa). The normal prestress of the bottom concrete of the member (positive under compression, negative under tension, MPa) is calculated using the following formula:

[0082] (7)

[0083] Among them, y n It is the distance (mm) from the centroid of the net section to the edge of the tension zone.

[0084] This embodiment distinguishes three cracking states of the cross-section (never cracked in the historical period, previously cracked but currently closed, and currently cracked), and determines the first effective moment of inertia of the concrete in different ways for each of the three cracking states. When the cross-section has never cracked, the gross moment of inertia is determined as the first effective moment of inertia of the concrete, reflecting the maximum stiffness before cracking. When the cross-section is currently cracked, the first effective moment of inertia of the concrete is determined based on the currently applied bending moment, reflecting the stiffness degradation under the current cracking state. When the cross-section was previously cracked but is currently closed, the historical maximum bending moment is introduced, retaining damage memory after crack closure, and the first effective moment of inertia of the concrete is determined based on the historical maximum bending moment, so that the cross-section stiffness is between the gross moment of inertia of the cross-section and the moment of inertia of the cracked cross-section. Therefore, the influence of the cracking state on the first effective moment of inertia of the concrete is considered, which in turn affects the concrete stress, enabling a more accurate determination of the actual stiffness evolution of the cracked cross-section, thereby improving the accuracy of concrete stress calculation.

[0085] In an exemplary embodiment, step 203 includes: determining the average concrete stress based on the concrete stress of each section; and determining the prestress loss caused by concrete shrinkage and creep based on the average concrete stress, shrinkage strain parameters, and a first creep coefficient.

[0086] For example, firstly, the average concrete stress (i.e., the average value of the concrete stress along the span) is determined based on the total length of the prestressed concrete member and the concrete stress at each section. The calculation formula can be:

[0087] (8)

[0088] in, This represents the average concrete stress.

[0089] Then, based on the elastic modulus of the prestressing tendons and the shrinkage strain parameters from the tensioning age t0 to the current time t, the prestress loss caused by concrete shrinkage is determined; and based on the ratio of the elastic modulus of the prestressing tendons to that of the concrete, the average concrete stress, and the first creep coefficient from the tensioning age t0 to the current time t, the prestress loss caused by concrete creep is determined. Finally, based on the prestress loss caused by concrete shrinkage and the prestress loss caused by concrete creep, the prestress loss caused by both concrete shrinkage and creep is determined.

[0090] Alternatively, the prestress loss caused by concrete shrinkage and creep can be calculated using the following formula:

[0091] (9)

[0092] (10)

[0093] (11)

[0094] e ps =(A p e p +A s e s ) / (A p +A s (12)

[0095] in, E represents the prestress loss caused by concrete shrinkage and creep at the current time t; 0.9 is a reduction factor introduced to account for the effect of prestressing tendon relaxation on creep loss; p ε is the elastic modulus of the prestressed tendon; cs (t, t0) represents the contraction strain parameter from the tensioning age t0 to the current time t; α EPφ is the ratio of the elastic modulus of the prestressing tendon to that of the concrete; φ(t,t0) is the first creep coefficient from the tensioning age t0 to the current time t; ρ is the reinforcement ratio in the tension zone. These are the geometric characteristic coefficients of the cross section. , These are the net moment of inertia and net cross-sectional area, respectively; e ps A is the distance from the resultant point of the prestressed tendons and non-prestressed reinforcing bars to the centroid of the net section. p e is the cross-sectional area of ​​the prestressing tendon. p A is the eccentricity of the resultant force of the prestressing tendons. s e represents the cross-sectional area of ​​the non-prestressed tendons. s It represents the eccentricity of the resultant force of the non-prestressed tendons. This refers to the loss of prestress caused by concrete shrinkage. This refers to the loss of prestress caused by concrete creep.

[0096] Therefore, in this embodiment, the concrete stress σ at the centroid of the prestressing tendon is used as the reference. psc (z,t) and its average value along the span By incorporating the mechanism of "cracking leading to cross-sectional stiffness degradation → cross-sectional stress redistribution → creep leading to prestress loss" into the prestress loss calculation model as the key variable, the prediction deviation of prestress loss can be reduced.

[0097] In one exemplary embodiment, such as Figure 5 As shown, the method further includes steps 501 to 503. Wherein:

[0098] Step 501: Determine the second net effective moment of inertia of the section based on the second effective moment of inertia of the concrete and the non-prestressed tendon at the loading age of each section in the prestressed concrete member.

[0099] The effective moment of inertia of the second concrete is determined based on the cracking state information of the section at the loading age and the cracking state information during the period from the tensioning age t0 to the loading age t1. The specific calculation method can be found in formula (5), which will not be repeated here.

[0100] For example, firstly, the cracking state information at the loading age and the cracking state information during the period from the tensioning age t0 to the loading age t1 are obtained, and then the second effective moment of inertia of the concrete section is calculated based on this information. Then, the second net effective moment of inertia of the section is determined according to the sum of the effective moment of inertia of the second concrete section and the moment of inertia of the non-prestressed tendons. The calculation method can be found in formula (1).

[0101] Step 502: Determine the first damage degree factor of the cross section based on the effective moment of inertia of the second net cross section.

[0102] The first damage factor is used to characterize the degree of stiffness degradation of the cross section caused by concrete cracking.

[0103] For example, the first damage degree factor of the cross section is calculated using the following formula. :

[0104] (13)

[0105] in, The effective moment of inertia of the second net section at loading age t1, The moment of inertia of the net cross section before cracking.

[0106] Step 503: Determine the long-term deflection of the prestressed concrete member based on the second creep coefficient of the prestressed concrete member from the loading age to the current time and the first damage degree factor of each section.

[0107] Long-term deflection is used to characterize the deflection performance of prestressed concrete members.

[0108] In one example, the steps include: determining the theoretical damage factor of the prestressed concrete member based on the first damage factor for each section; determining the long-term deflection growth factor of the prestressed concrete member based on the second creep coefficient and the theoretical damage factor; and determining the long-term deflection based on the long-term deflection growth factor and the initial deflection of the prestressed concrete member.

[0109] For example, firstly, the damage degree factor representing a section (such as the mid-span section) is obtained from the first damage degree factor of each section as the theoretical damage degree factor, or the theoretical damage degree factor is calculated based on the first damage degree factor of each section; then, the long-term deflection growth coefficient is determined based on the second creep coefficient and the theoretical damage degree factor, and the long-term deflection growth coefficient of the component can be calculated using the following formula:

[0110] (14)

[0111] Where φ(t,t1) is the second creep coefficient from loading age t1 to the current time t; D f is the theoretical damage severity factor at loading age t1; k is a parameter (which can be calibrated experimentally, and can be taken as 2.62 if no experimental data is available).

[0112] Finally, the long-term deflection is calculated using the following formula in the form of component superposition. :

[0113] (15)

[0114] in, It is the initial deflection at loading age t1. Let represent the effective moment of inertia of the second net section at loading age t1. The effective prestress at loading age t1 is calculated using the following formula: , σ pe This represents the initial tensile stress of the prestressing tendons. The total prestress loss from the tensioning age t0 to the loading age t1 is calculated using formula (4).

[0115] In this embodiment, the first damage degree factor of the cross section is determined based on the effective moment of inertia of the second net cross section considering the cracking state of the cross section, which can improve the accuracy of the first damage degree factor. Furthermore, considering the impact of cracking on the long-term deflection growth coefficient can improve the calculation accuracy of the long-term deflection growth coefficient, thereby improving the accuracy of the long-term deflection assessment.

[0116] In one exemplary embodiment, such as Figure 6 As shown, based on the second creep coefficient and the theoretical damage factor, the long-term deflection growth coefficient of the prestressed concrete member is determined, including steps 601 to 604:

[0117] Step 601: Obtain the horizontal strain values ​​at each analysis point within the preset area of ​​the prestressed concrete member.

[0118] For example, such as Figure 7 As shown, speckle patterns are laid out in a predetermined area of ​​the prestressed concrete member (e.g., the area where mid-span cracks may develop), and loading points are set above the member to apply external loads. A high-speed camera is positioned directly in front of the member to acquire speckle images of the member surface. After analysis using a Digital Image Correlation (DIC) algorithm, the horizontal strain values ​​of each analysis point within the predetermined area are extracted. Each analysis point corresponds to a grid point within the analysis area, and the horizontal strain value reflects the degree of deformation at that point along the member's span direction.

[0119] Step 602: Determine the measured damage factor of the prestressed concrete member based on the strain values ​​at each level.

[0120] In one example, step 602 includes: determining a first average level strain value for all horizontal strain values; sorting the horizontal strain values ​​in descending order and determining a second average level strain value for a first preset number of horizontal strain values; and determining a damage degree factor based on the first average level strain value and the second average level strain value.

[0121] The preset number is the first a%, where a is the quantile threshold. Through sensitivity analysis, a can be taken as 5%.

[0122] For example, firstly, the first average level strain value of all horizontal strain values ​​is calculated; then, the horizontal strain values ​​of all analysis points within the preset area are sorted from largest to smallest, and the first a% of strain points are selected to calculate the second average level strain value of these points. Next, the difference between the second average level strain value and the first average level strain value is calculated to obtain the strain concentration value. Based on this strain concentration value and the maximum strain concentration value when the component is completely destroyed, a normalized measurement damage factor is obtained.

[0123] Alternatively, the strain concentration value can be calculated using the following formula:

[0124] (16)

[0125] in, Let be the horizontal strain value at the i-th analysis point; N is the total number of analysis points.

[0126] The damage severity factor is calculated using the following formula. :

[0127] (17)

[0128] in, The maximum strain concentration when the component is completely destroyed can be taken as 2%.

[0129] Step 603: If the relative deviation between the measured damage degree factor and the theoretical damage degree factor is greater than a preset deviation threshold, the theoretical damage degree factor is updated based on the measured damage degree factor to obtain the updated damage degree factor.

[0130] For example, after the measured damage degree factor is calculated based on the DIC strain field, it is compared with the theoretical damage degree factor D calculated by formula (13). f By comparison, the relative deviation δ between the two is calculated:

[0131] (18)

[0132] The relative deviation is compared with a deviation threshold (e.g., 3%). When δ ≤ 3%, it indicates that the theoretical damage degree factor meets the accuracy requirements, and no correction is performed. When δ(t) > 3%, the deviation correction mechanism is triggered. right The replacement is performed to obtain the updated damage factor.

[0133] Step 604: Determine the long-term deflection growth coefficient based on the second creep coefficient and the updated damage degree factor.

[0134] For example, the updated damage factor is substituted into formula (14) to recalculate the long-term deflection growth coefficient and the long-term deflection is recalculated.

[0135] Therefore, this embodiment introduces DIC crack identification. When the deviation between the theoretical damage degree factor and the measured damage degree factor exceeds the threshold (3%), a correction mechanism is triggered to update the theoretical damage degree factor, the subsequent long-term deflection growth coefficient, and the long-term deflection, thereby correcting the long-term deflection result. This overcomes the problem of the long-term deflection prediction model lacking experimental verification and has usability and engineering credibility.

[0136] The method of this application embodiment is described below with a detailed example, specifically including the following steps:

[0137] S1, input the section and reinforcement parameters, material performance parameters, prestressing construction parameters, and load history parameters of the prestressed concrete member; where:

[0138] Section and reinforcement parameters include: net cross-sectional area A n eccentricity e of the resultant force of prestressing tendons p Net moment of inertia I n , converted moment of inertia of section I0, plastic influence coefficient of section modulus γ, moment of inertia of uncracked concrete section I g ;

[0139] Material performance parameters include: the shrinkage strain parameter ε from the tensioning age t0 to the current time t. cs (t,t0), the first creep coefficient φ from tensioning age t0 to time t. (t, t0), elastic modulus of prestressed tendons E p E, the elastic modulus of concrete con ζ, relaxation coefficient of prestressed tendons, tensile strength of concrete, ultimate tensile strength of prestressed tendons f ptk ;

[0140] Prestressed construction parameters and load history parameters include: initial tension stress σ of the prestressing tendon. pe , over-tension coefficient ψ, and bending moment M(t) generated by external load;

[0141] S2, calculate the prestress loss caused by the relaxation of prestressing tendons using formula (3);

[0142] S3, calculate the initial cracking moment of each section using formula (6);

[0143] S4, calculate the first effective moment of inertia of concrete at each section using formula (5);

[0144] S5, calculate the effective moment of inertia of the first net section of each section using formula (1);

[0145] S6, calculate the concrete stress at the centroid of the prestressing tendons in each section using formula (2);

[0146] S7, calculate the average concrete stress using formula (8);

[0147] S8, calculate the prestress loss caused by concrete shrinkage and creep using formula (9);

[0148] S9, calculate the total prestress loss of the prestressed concrete member using formula (4);

[0149] S10, calculate the first damage degree factor of each section using formula (13), and determine the theoretical damage degree factor of the component based on each first damage degree factor;

[0150] S11, calculate the long-term deflection growth coefficient of the component using formula (14);

[0151] S12, calculate the long-term deflection of the component using formula (15);

[0152] S13, calculate the measured damage factor of the component using formula (17);

[0153] S14. If the relative deviation between the measured damage degree factor and the theoretical damage degree factor is greater than the preset deviation threshold, then execute S15; otherwise, execute S16.

[0154] S15, update the theoretical damage degree factor based on the measured damage degree factor to obtain the updated damage degree factor, and return to S11.

[0155] S16 outputs total prestress loss, damage factor, and long-term deflection.

[0156] In summary, the embodiments of this application improve the accuracy of long-term prestress loss prediction for cracked prestressed members: They incorporate the degradation of effective moment of inertia caused by cracking, changes in the neutral axis position, and spatial distribution changes in concrete stress at the centroid of the prestressing tendons into the prestress loss calculation process, effectively reducing the prediction deviation of existing models under cracked conditions; they achieve quantifiable and feedback-updated damage severity factors: using a theoretical damage severity factor defined by the degradation of effective moment of inertia, and further constructing and measuring the damage severity factor based on high-quantile statistics of the DIC strain field, enhancing the accuracy of damage assessment; and they establish a verification and correction mechanism based on actual measurements, improving... Engineering reliability: When the deviation between the measured damage degree factor and the theoretical damage degree factor exceeds a threshold, a correction mechanism is triggered to update the theoretical damage degree factor, subsequent deflection growth coefficient, and long-term deflection prediction results, overcoming the problem of existing long-term prediction models lacking experimental verification; Integrated output and early warning of prestress loss, damage, and deflection: Prestress monitoring and crack / damage detection are uniformly connected to the evaluation terminal, which can simultaneously output prestress loss evaluation results, damage factor evolution, and long-term deflection prediction curves, providing directly applicable technical support for the long-term service performance evaluation and risk management of cracked prestressed components.

[0157] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages in other steps. It is understood that the steps in different embodiments can be freely combined as needed, and all non-contradictory solutions formed by such combinations are within the scope of protection of this application.

[0158] Based on the same inventive concept, this application also provides a performance evaluation device for prestressed concrete components to implement the performance evaluation method for prestressed concrete components described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations of one or more performance evaluation device embodiments for prestressed concrete components provided below can be found in the limitations of the performance evaluation method for prestressed concrete components described above, and will not be repeated here.

[0159] In one exemplary embodiment, such as Figure 8As shown, a performance evaluation device for prestressed concrete members is provided, comprising: a first determining module 801, a second determining module 802, a third determining module 803, and a fourth determining module 804, wherein:

[0160] The first determining module 801 is used to determine the first net effective moment of inertia of the section based on the first effective moment of inertia of the concrete and the moment of inertia of the non-prestressed tendons of each section in the prestressed concrete member at the current moment; wherein, the first effective moment of inertia of the concrete is determined based on the current cracking state information of the section and the cracking state information in the historical period.

[0161] The second determining module 802 is used to determine the concrete stress at the centroid of the prestressing tendons of the section based on the effective moment of inertia of the first net section and the current applied bending moment of the section.

[0162] The third determining module 803 is used to determine the prestress loss caused by concrete shrinkage and creep based on the concrete stress of each section, the shrinkage strain parameter of the prestressed concrete member and the first creep coefficient; wherein, the shrinkage strain parameter characterizes the cumulative shrinkage strain of the concrete in the prestressed concrete member during the historical period, and the first creep coefficient characterizes the creep of the concrete during the historical period.

[0163] The fourth determination module 804 is used to determine the total prestress loss of the prestressed concrete member based on the prestress loss caused by concrete shrinkage and creep; the total prestress loss is used to characterize the prestress performance of the prestressed concrete member.

[0164] In one embodiment, the apparatus further includes: a fifth determining module, configured to determine the first effective concrete moment of inertia of the cross-section based on the gross moment of inertia of the cross-section when the current applied bending moment of the cross-section is less than the initial cracking bending moment of the cross-section and the cross-section has not cracked during the historical period; a sixth determining module, configured to determine the first effective concrete moment of inertia of the cross-section based on the cracked cross-section moment of inertia, the initial cracking bending moment, the historical maximum bending moment, and the gross moment of inertia of the cross-section when the current applied bending moment of the cross-section is less than the initial cracking bending moment of the cross-section and the cross-section has cracked during the historical period; and a seventh determining module, configured to determine the first effective concrete moment of inertia of the cross-section based on the cracked cross-section moment of inertia, the initial cracking bending moment, the current applied bending moment, and the gross moment of inertia of the cross-section when the current applied bending moment of the cross-section is greater than or equal to the initial cracking bending moment of the cross-section and the cross-section has cracked during the historical period.

[0165] In one embodiment, the third determining module 803 is specifically used to: determine the average concrete stress based on the concrete stress of each section; and determine the prestress loss caused by concrete shrinkage and creep based on the average concrete stress, shrinkage strain parameters, and a first creep coefficient.

[0166] In one embodiment, the apparatus further includes: an eighth determining module, configured to determine a second net effective moment of inertia of the cross section based on the second effective moment of inertia of the concrete and the non-prestressed tendon moment of inertia of each cross section in the prestressed concrete member at the loading age; a ninth determining module, configured to determine a first damage degree factor of the cross section based on the second net effective moment of inertia of the cross section; the first damage degree factor is used to characterize the degree of stiffness degradation of the cross section due to concrete cracking; and a tenth determining module, configured to determine the long-term deflection of the prestressed concrete member based on the second creep coefficient of the prestressed concrete member from the loading age to the current moment and the first damage degree factor of each cross section; the long-term deflection is used to characterize the deflection performance of the prestressed concrete member.

[0167] In one embodiment, the tenth determining module is specifically used to: determine the theoretical damage degree factor of the prestressed concrete member based on the first damage degree factor of each section; determine the long-term deflection growth coefficient of the prestressed concrete member based on the second creep coefficient and the theoretical damage degree factor; and determine the long-term deflection based on the long-term deflection growth coefficient and the initial deflection of the prestressed concrete member.

[0168] In one embodiment, the tenth determining module is further configured to: obtain the horizontal strain values ​​of each analysis point within a preset area of ​​the prestressed concrete member; determine the measured damage degree factor of the prestressed concrete member based on each horizontal strain value; update the theoretical damage degree factor according to the measured damage degree factor when the relative deviation between the measured damage degree factor and the theoretical damage degree factor is greater than a preset deviation threshold, and obtain the updated damage degree factor; and determine the long-term deflection growth coefficient based on the second creep coefficient and the updated damage degree factor.

[0169] In one embodiment, the tenth determining module is further configured to: determine a first average level strain value for all horizontal strain values; sort the horizontal strain values ​​in descending order and determine a second average level strain value for the first preset number of horizontal strain values; and determine a damage degree factor based on the first average level strain value and the second average level strain value.

[0170] Each module in the aforementioned performance evaluation device for prestressed concrete components can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0171] In one exemplary embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 9As shown, the computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores performance evaluation data for prestressed concrete components. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communicating with external terminals via a network connection. When the computer program is executed by the processor, it implements a performance evaluation method for prestressed concrete components.

[0172] Those skilled in the art will understand that Figure 9 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0173] In one exemplary embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement a method for evaluating the performance of prestressed concrete members.

[0174] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements a method for evaluating the performance of prestressed concrete members.

[0175] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements a method for evaluating the performance of prestressed concrete members.

[0176] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0177] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0178] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for evaluating the performance of prestressed concrete members, characterized in that, The method includes: The first net effective moment of inertia of the prestressed concrete member is determined based on the first effective moment of inertia of the concrete at the current moment and the moment of inertia of the non-prestressed tendons of the section; wherein the first effective moment of inertia of the concrete is determined based on the current cracking state information of the section and the cracking state information in the historical period. Based on the effective moment of inertia of the first net section of the cross section and the currently applied bending moment of the cross section, determine the concrete stress at the centroid of the prestressing tendons of the cross section; Based on the concrete stress at each section, the shrinkage strain parameter of the prestressed concrete member, and the first creep coefficient, the prestress loss caused by concrete shrinkage and creep is determined; wherein, the shrinkage strain parameter characterizes the cumulative shrinkage strain of the concrete in the prestressed concrete member during the historical period, and the first creep coefficient characterizes the creep of the concrete during the historical period. The total prestress loss of the prestressed concrete member is determined based on the prestress loss caused by concrete shrinkage and creep; the total prestress loss is used to characterize the prestress performance of the prestressed concrete member.

2. The method according to claim 1, characterized in that, The method for determining the effective moment of inertia of the first concrete includes: If the current applied bending moment at the cross section is less than the initial cracking bending moment at the cross section, and the cross section has not cracked during the historical period, the first effective concrete moment of inertia of the cross section is determined based on the gross moment of inertia of the cross section. If the current applied bending moment at the cross section is less than the initial cracking bending moment at the cross section, and the cross section has cracked during the historical period, the first effective concrete moment of inertia of the cross section is determined based on the cracked section moment of inertia, the initial cracking bending moment, the historical maximum bending moment, and the gross section moment of inertia. If the current applied bending moment of the cross section is greater than or equal to the initial cracking bending moment of the cross section, and the cross section has cracked during the historical period, the first effective concrete moment of inertia of the cross section is determined based on the moment of inertia of the cracked cross section, the initial cracking bending moment, the current applied bending moment, and the gross cross section moment of inertia.

3. The method according to claim 1, characterized in that, The determination of prestress loss caused by concrete shrinkage and creep, based on the concrete stress at each cross-section, the shrinkage strain parameters of the prestressed concrete member, and the first creep coefficient, includes: The average concrete stress is determined based on the concrete stress described at each section. The prestress loss caused by concrete shrinkage and creep is determined based on the average concrete stress, the shrinkage strain parameter, and the first creep coefficient.

4. The method according to any one of claims 1-3, characterized in that, The method further includes: The second net effective moment of inertia of the section is determined based on the second effective moment of inertia of the concrete at the loading age and the moment of inertia of the non-prestressed tendons for each section in the prestressed concrete member. Based on the effective moment of inertia of the second net section of the cross-section, a first damage degree factor of the cross-section is determined; the first damage degree factor is used to characterize the degree of stiffness degradation of the cross-section caused by concrete cracking. The long-term deflection of the prestressed concrete member is determined based on the second creep coefficient from the loading age to the current time and the first damage degree factor of each section; the long-term deflection is used to characterize the deflection performance of the prestressed concrete member.

5. The method according to claim 4, characterized in that, The determination of the long-term deflection of the prestressed concrete member based on the second creep coefficient of the prestressed concrete member from the loading age to the present time and the first damage degree factor of each section includes: The theoretical damage factor of the prestressed concrete member is determined based on the first damage factor of each of the aforementioned sections. Based on the second creep coefficient and the theoretical damage factor, the long-term deflection growth coefficient of the prestressed concrete member is determined. The long-term deflection is determined based on the long-term deflection growth coefficient and the initial deflection of the prestressed concrete member.

6. The method according to claim 5, characterized in that, The determination of the long-term deflection growth coefficient of the prestressed concrete member based on the second creep coefficient and the theoretical damage degree factor includes: Obtain the horizontal strain values ​​at each analysis point within the preset area of ​​the prestressed concrete member; The measured damage factor of the prestressed concrete member is determined based on each of the horizontal strain values. If the relative deviation between the measured damage degree factor and the theoretical damage degree factor is greater than a preset deviation threshold, the theoretical damage degree factor is updated based on the measured damage degree factor to obtain the updated damage degree factor. The long-term deflection growth coefficient is determined based on the second creep coefficient and the updated damage degree factor.

7. The method according to claim 6, characterized in that, The determination of the measured damage degree factor of the prestressed concrete member based on each of the horizontal strain values ​​includes: Determine the first average level strain value for all the stated level strain values; The horizontal strain values ​​are sorted in descending order, and the second average level strain value of the first preset number of horizontal strain values ​​is determined. The measured damage degree factor is determined based on the first average level strain value and the second average level strain value.

8. A performance evaluation device for prestressed concrete components, characterized in that, The device includes: The first determining module is used to determine the first net effective moment of inertia of the prestressed concrete member based on the first effective moment of inertia of the concrete at the current moment and the non-prestressed tendon moment of inertia of the section; wherein the first effective moment of inertia of the concrete is determined based on the current cracking state information of the section and the cracking state information in the historical period. The second determining module is used to determine the concrete stress at the centroid of the prestressing tendons of the cross section based on the effective moment of inertia of the first net cross section and the current applied bending moment of the cross section. The third determining module is used to determine the prestress loss caused by concrete shrinkage and creep based on the concrete stress of each section, the shrinkage strain parameter of the prestressed concrete member, and the first creep coefficient; wherein the shrinkage strain parameter characterizes the cumulative shrinkage strain of the concrete in the prestressed concrete member during the historical period, and the first creep coefficient characterizes the creep of the concrete during the historical period. The fourth determining module is used to determine the total prestress loss of the prestressed concrete member based on the prestress loss caused by concrete shrinkage and creep; the total prestress loss is used to characterize the prestress performance of the prestressed concrete member.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 7.

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