A method and system for coordinating control of shrinkage and creep in new and old spliced bridge expansion joints

Abstract

This invention discloses a method and system for coordinated control of shrinkage and creep at the joint between new and old concrete sections in bridge reconstruction and expansion projects, relating to the field of bridge reconstruction and expansion technology. The method includes: acquiring characteristic parameters of the new and old concrete, calculating the shrinkage strain, creep coefficient, and effective elastic modulus of the new and old concrete, and then obtaining the differential deformation compatibility index. Based on this, the differential normal stress at the joint interface is calculated, and the interface activation time is determined jointly by stiffness matching and interface strength criteria (the earliest time when both are simultaneously satisfied). After activation, the interface is roughened, the bonding concrete is poured, and grouting is carried out according to the staged grouting pressure equation. The dynamic prestress compensation amount is calculated based on the differential deformation compatibility index and the interface differential normal stress, and adjustable prestressed anchors are tensioned in stages. The crack width is monitored throughout the process, and a feedback adjustment coefficient is calculated based on the width ratio to adaptively correct the prestress compensation amount.

Description

Technical Field

[0001] This invention belongs to the field of bridge reconstruction and expansion technology, and in particular relates to a method and system for coordinated control of shrinkage and creep of the old and new splice zone of a reconstructed or expanded bridge. Background Technology

[0002] In highway bridge reconstruction and expansion projects, when the existing bridge (hereinafter referred to as the old bridge) and the newly widened section (hereinafter referred to as the new bridge) are joined laterally, there are significant differences in shrinkage, creep, and temperature effects between the two, as the pouring time of the old and new concrete is usually more than ten years. The old concrete has basically completed its shrinkage and creep deformation, while the newly poured concrete is in the active shrinkage and creep period. This age difference leads to large differential deformation in the splice zone in the early stage of service, which in turn causes uneven stress distribution at the splice interface, and may eventually lead to cracking, delamination, and even degradation of the overall structural performance.

[0003] The existing methods for splicing new and old concrete in bridge reconstruction and expansion have the following main defects: First, there is a lack of a quantitative description system for the differential deformation of new and old concrete, making dynamic quantitative assessment impossible; second, the timing of interface treatment is determined by experience, lacking scientific activation criteria; third, the prestress compensation amount is fixed once designed and cannot be adaptively adjusted according to the actual differential deformation state; fourth, the grouting construction parameters are not updated with the time-varying state of the components, posing a risk of insufficient grouting or over-grouting. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a method for coordinated control of shrinkage and creep at the joint between old and new sections of an expanded or reconstructed bridge, comprising: Step 1: Obtain the characteristic parameters of new and old concrete, and calculate the shrinkage strain of new concrete, shrinkage strain of old concrete, effective elastic modulus of new concrete, creep coefficient of new concrete and creep coefficient of old concrete at any time, so as to calculate the differential deformation compatibility index that comprehensively reflects the difference in shrinkage, creep and temperature. Step 2: Calculate the differential deformation compatibility index and the effective elastic modulus of the new concrete, calculate the differential normal stress at the splicing interface, and determine the interface activation time by combining the stiffness matching criterion and the interface strength safety criterion. Take the earliest time when both criteria are satisfied at the same time as the interface activation time. Step 3: When the interface activation time is reached, mechanical roughening of the interface and concrete pouring of the interface are carried out in sequence. Then, the grouting pressure of each stage is determined according to the staged grouting pressure control equation and staged grouting is carried out. Step 4: Calculate the dynamic prestress compensation based on the differential deformation compatibility index and the differential normal stress at the splicing interface, and implement tensioning in stages by setting adjustable prestressed anchors laterally in the new and old splicing strips. Step 5: Conduct full-cycle crack width monitoring on the splicing interface, calculate the monitoring feedback adjustment coefficient based on the ratio of the monitored crack width to the allowable crack width limit of the splicing interface, and adaptively correct the dynamic prestress compensation amount based on the monitoring feedback adjustment coefficient.

[0005] Furthermore, the differential deformation compatibility index includes: , in, For a moment The time-varying deformation compatibility index For a moment The difference in shrinkage strain between old and new concrete at that time For a moment The difference in creep coefficient between old and new concrete at that time For a moment The temperature difference between the old and new concrete at that time For reference shrinkage strain, For reference creep coefficient, For reference temperature difference, For contraction weighting coefficients, For creep weighting coefficients, This is the temperature weighting coefficient.

[0006] Furthermore, the calculation of shrinkage strain in the new concrete includes: , in, For a moment Shrinkage strain of new concrete at that time This represents the ultimate shrinkage strain of the new concrete. This is the correction factor for relative humidity. This is the correction factor for the strength of the new concrete. This is the shrinkage rate coefficient of the new concrete. This marks the completion time of the new standard curing process for concrete. For normalized reference time, This is the shrinkage morphology index for new concrete.

[0007] Furthermore, the calculation of the creep coefficient of new concrete includes: , in, Self-loading age of new concrete At that time The new concrete creep coefficient, This represents the ultimate creep coefficient of the new concrete foundation. To determine the characteristic compressive strength of new concrete The new concrete strength reduction factor is a parameter. This refers to the creep development pattern index. To load the age-related influence coefficient, To load the age decay index, The age at which new concrete is first subjected to load. This is a normalized reference time.

[0008] Furthermore, the stiffness matching criterion is as follows: , The interface strength safety criteria are: , in, For a moment Effective elastic modulus of modern concrete The elastic modulus of the old concrete. This is the stiffness activation threshold coefficient. The compatibility index is the sensitivity coefficient. For a moment The time-varying deformation compatibility index For a moment Axial tensile strength of new concrete For the interface tensile safety factor, For a moment The difference in normal stress at the splicing interface.

[0009] Furthermore, the staged grouting pressure control equations include: , in, For a moment Time Grouting pressure at each grouting stage, This is the design value for the maximum grouting pressure. This represents the total number of grouting stages. The grouting pressure growth coefficient is... For a moment The difference in normal stress at the splicing interface For a moment Axial tensile strength of new concrete This is a factor for adjusting the interface state.

[0010] Furthermore, the calculation of dynamic prestress compensation includes: , Among them, the prestressing aging amplification factor Calculate using the following formula: , in, For a moment Prestressing aging amplification factor, For a moment Dynamic prestress compensation amount The effective area of ​​the interface between the old and new parts. For a moment The difference in normal stress at the splicing interface This is the critical compatibility index. This is the prestress amplification sensitivity coefficient. The prestressed aging morphology index, For prestress compensation characteristic time parameters, When the interface is activated, This is a normalized reference time.

[0011] Furthermore, calculate the monitoring feedback adjustment coefficient. : , in, For a moment Real-time monitoring and feedback adjustment coefficient The maximum adjustment range coefficient. For mathematical constants, To adjust the sensitivity coefficient, For a moment The width of the crack at the splicing interface was monitored in real time. To limit the allowable width of cracks at the splicing interface; time Dynamic prestress compensation amount after adaptive correction for: .

[0012] This invention also proposes a coordinated control system for shrinkage and creep of the splice zone between old and new bridges in reconstruction and expansion projects, comprising: The first calculation module is used to obtain the characteristic parameters of new and old concrete, and calculate the shrinkage strain of new concrete, shrinkage strain of old concrete, effective elastic modulus of new concrete, creep coefficient of new concrete and creep coefficient of old concrete at any time, so as to calculate the differential deformation compatibility index that comprehensively reflects the difference in shrinkage, creep and temperature. The interface activation time determination module is used to calculate the differential deformation compatibility index and the effective elastic modulus of new concrete, calculate the differential normal stress at the splicing interface, and jointly determine the interface activation time by the stiffness matching criterion and the interface strength safety criterion, taking the earliest time when both criteria are satisfied as the interface activation time. The grouting module is used to sequentially perform interface mechanical roughening treatment, interface bonding concrete pouring, and staged grouting after determining the grouting pressure of each stage according to the staged grouting pressure control equation when the interface activation time is reached. The tensioning module is used to calculate the dynamic prestress compensation based on the differential deformation compatibility index and the differential normal stress at the splice interface, and to implement tensioning in stages through adjustable prestressed anchor cables set laterally in the new and old splice strips. The correction module is used to monitor the crack width of the splicing interface throughout the entire cycle. It calculates the monitoring feedback adjustment coefficient based on the ratio of the monitored crack width of the splicing interface to the allowable crack width limit of the splicing interface, and performs adaptive correction on the dynamic prestress compensation amount based on the monitoring feedback adjustment coefficient.

[0013] Furthermore, the differential deformation compatibility index includes: the differential deformation compatibility index described in step two. Calculate using the following formula: , in, For a moment The time-varying deformation compatibility index For a moment The difference in shrinkage strain between old and new concrete at that time For a moment The difference in creep coefficient between old and new concrete at that time For a moment The temperature difference between the old and new concrete at that time For reference shrinkage strain, For reference creep coefficient, For reference temperature difference, For contraction weighting coefficients, For creep weighting coefficients, This is the temperature weighting coefficient.

[0014] like Figure 5 As shown, compared with the prior art, the present invention has the following advantages and technical effects: (1) A quantitative evaluation system for the differential deformation compatibility index was established. This was achieved by introducing the differential deformation compatibility index. This method integrates three physical quantities—shrinkage difference, creep difference, and temperature difference—into a dimensionless comprehensive index, enabling real-time quantitative description of the degree of differential deformation between new and old concrete. This overcomes the shortcomings of existing methods that cannot quantitatively assess differential deformation.

[0015] (2) A multi-criteria method for determining the interface activation time was proposed. By combining the stiffness matching criterion (criterion A) and the interface strength safety criterion (criterion B), the optimal timing for interface activation was scientifically determined. This avoids the stress concentration at the interface caused by insufficient stiffness of the new concrete due to premature activation, and also prevents the problem of excessive accumulation of differential deformation at an older age due to delayed activation.

[0016] (3) Adaptive control of dynamic prestress compensation was achieved. This was achieved by adjusting the prestress compensation amount with the differential deformation compatibility index. By monitoring crack width in real time, the amount of prestress compensation can be dynamically adjusted according to the actual condition of the component, which significantly improves the pertinence and effectiveness of prestress compensation.

[0017] (4) A phased precision grouting control model was established. By jointly controlling the grouting pressure with the interfacial stress ratio and the phase sequence, the gradient precision control of the grouting pressure was achieved, eliminating the risk of insufficient or excessive grouting caused by fixed grouting pressure. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a flowchart of the method in Embodiment 1 of the present invention; Figure 2 This is a system structure diagram of Embodiment 2 of the present invention; Figure 3 This is a system structure diagram of Embodiment 4 of the present invention; Figure 4 This is a schematic diagram of the structural layout and control system of the new and old splicing belts; Figure 5 This is a rendering of the invention. Detailed Implementation

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0021] Example 1 like Figure 1 As shown in the figure, this embodiment proposes a method for coordinated control of shrinkage and creep at the joint between old and new bridge sections during reconstruction and expansion, including: Step 1: Obtain the characteristic parameters of new and old concrete, and calculate the shrinkage strain of new concrete, shrinkage strain of old concrete, effective elastic modulus of new concrete, creep coefficient of new concrete and creep coefficient of old concrete at any time, so as to calculate the differential deformation compatibility index that comprehensively reflects the difference in shrinkage, creep and temperature. Preferably, before pouring new concrete, the following characteristic parameters are determined by in-situ sampling and testing of the old bridge concrete and by mix proportioning tests of the new bridge concrete: (1) Characteristic parameters of new concrete: ultimate shrinkage strain Shrinkage rate coefficient Contraction morphology index 28-day elastic modulus 28-day axial tensile strength Cement type coefficient aging coefficient Basic limit creep coefficient ; (2) Characteristic parameters of old concrete: ultimate shrinkage strain Shrinkage rate coefficient Contraction morphology index Elastic modulus Current age ; (3) Expected maximum temperature difference between new and old concrete during construction Effective area of ​​the interface between the old and new splicing .

[0022] Specifically, the differential deformation compatibility index includes: , in, For a moment The time-varying deformation compatibility index For a moment The difference in shrinkage strain between old and new concrete at that time For a moment The difference in creep coefficient between old and new concrete at that time For a moment The temperature difference between the old and new concrete at that time For reference shrinkage strain, For reference creep coefficient, For reference temperature difference, For contraction weighting coefficients, For creep weighting coefficients, Temperature weighting coefficient, .

[0023] Specifically, calculating the shrinkage strain of new concrete includes: , in, For a moment Shrinkage strain of new concrete at that time The ultimate shrinkage strain of new concrete (dimensionless) reflects the maximum shrinkage of new concrete in a completely dry state. Typical values ​​are given for C60 concrete under standard curing conditions. This is a dimensionless correction factor for relative humidity. It is set to 1.35 for RH = 40%, 1.00 for RH = 70%, and 0.62 for RH = 90%. This is the new concrete strength correction factor (dimensionless). This is the shrinkage rate coefficient of new concrete (dimensionless), reflecting the rate of shrinkage development in new concrete. The larger the value, the faster the shrinkage development. This marks the completion time of the new standard curing process for concrete. For normalized reference time, The shrinkage morphology index (dimensionless) is used to control the shape of the shrinkage curve over time. A value less than 1 indicates that the shrinkage develops rapidly in the early stage.

[0024] Calculate the new concrete strength correction factor include: , in, The strength sensitivity index (dimensionless) reflects the sensitivity of shrinkage strain to the strength grade of concrete. For reference characteristic compressive strength, Calculating the shrinkage strain of old concrete includes: , in, For a moment Shrinkage strain of old concrete at that time The value represents the ultimate shrinkage strain (dimensionless) of old concrete, a typical value for C40 old bridge concrete. The age (d) of the old concrete when pouring new concrete is typically used for bridge reconstruction and expansion. (That is, 20 years), at which point the old concrete is close to its limit shrinkage state; The shrinkage rate coefficient of old concrete (dimensionless). The shrinkage morphology index of old concrete (dimensionless). The environmental humidity correction factor for old concrete (dimensionless) is determined according to the following rules: same; The strength correction factor for old concrete (dimensionless), C40 old bridge concrete. ,in, The characteristic compressive strength (MPa) of the old concrete.

[0025] Calculating the time-varying elastic modulus of new concrete includes: , in, For a moment The time-varying elastic modulus of new concrete at that time, The 28-day elastic modulus (MPa) of new concrete, C60 concrete is taken as follows. ; The coefficient is the cement type coefficient (dimensionless). It is 0.25 for ordinary Portland cement, 0.20 for rapid-hardening Portland cement, and 0.38 for slow-hardening cement.

[0026] The effective elastic modulus of new concrete considering the effects of creep includes: , in, For a moment The effective elastic modulus of new concrete at that time The aging coefficient of new concrete (dimensionless) reflects the degree of degradation of the elastic properties of concrete during continuous loading. The age (days) at which the first load is applied to new concrete is generally taken as... .

[0027] Specifically, calculating the creep coefficient of new concrete includes: , in, Self-loading age of new concrete At that time The new concrete creep coefficient, This represents the ultimate creep coefficient of the new concrete foundation. To determine the characteristic compressive strength of new concrete The new concrete strength reduction factor is a parameter. This refers to the creep development pattern index. To load the age-related influence coefficient, To load the age decay index, The age at which new concrete is first subjected to load. This is a normalized reference time.

[0028] Calculating the creep coefficient of old concrete includes: , in, Self-loading age of old concrete At that time The creep coefficient of old concrete. is the ultimate creep coefficient of the old concrete foundation (dimensionless). The characteristic compressive strength of old concrete The old concrete strength reduction factor (dimensionless) is a parameter for C40 old bridge concrete. ; The creep development morphology index of old concrete (dimensionless). The influence coefficient of loading age of old concrete (dimensionless). The decay index of old concrete at loading age (dimensionless).

[0029] when At that time, the creep of the old concrete had approached its final value. Follow The change is very small and can be approximated as a constant; With China They are in the same format, but the subscripts distinguish between new and old concrete.

[0030] Step 2: Calculate the differential deformation compatibility index and the effective elastic modulus of the new concrete, calculate the differential normal stress at the splicing interface, and determine the interface activation time by combining the stiffness matching criterion and the interface strength safety criterion. Take the earliest time when both criteria are satisfied at the same time as the interface activation time. Preferably, the calculation time Stiffness compatibility reduction factor : , in, The elastic modulus (MPa) of the old concrete is taken from C40 old bridge concrete. ; This is the interface stiffness activation rate coefficient (dimensionless), which controls the activation rate of interface contact stiffness as it ages. The larger the value, the faster the interface stiffness is activated.

[0031] Calculate the differential normal stress at the splicing interface : , in, The initial elastic strain reference value for new concrete (dimensionless) corresponds to a reference stress level of approximately 14.4 MPa (from...). get); Specifically, the moment the interface is activated. The following two criteria must be met simultaneously, and the earliest time when both criteria are met is taken: The stiffness matching criterion is: , The interface strength safety criteria are: , in, For a moment Effective elastic modulus of modern concrete The elastic modulus of the old concrete. This is the stiffness activation threshold coefficient. The compatibility index is the sensitivity coefficient. For a moment The time-varying deformation compatibility index For a moment Axial tensile strength of new concrete For the interface tensile safety factor, For a moment The difference in normal stress at the splicing interface.

[0032] Calculate the axial tensile strength of the new concrete: , in, The axial tensile strength (MPa) of new concrete after 28 days is taken from C60 concrete. ; Step 3: Upon reaching the interface activation moment, sequentially perform interface mechanical roughening treatment, interface bonding concrete pouring, and then implement staged grouting after determining the grouting pressure for each stage according to the staged grouting pressure control equation (e.g., Figure 4 (as shown) Preferably, the interface activation time is confirmed when the dual criteria described in step two are met. Then, the phased interface treatment is carried out according to this procedure. The grouting pressure in each phase is uniformly controlled by the phased grouting pressure control equation to ensure that the grouting pressure is adapted to the real-time stress state of the interface.

[0033] (1) At time Before the arrival, the old concrete interface is mechanically roughened to a depth of not less than 6 mm. After roughening, the interface is cleaned and kept moist. (2) At time The interface bonding concrete shall be poured at the same time, and the strength grade of the bonding concrete shall not be lower than that of the new bridge concrete, and not lower than C50. (3) Calculate the grouting pressure at each stage according to the staged grouting pressure control equation. Grouting was carried out in stages through the reserved grouting holes of the splicing strip.

[0034] Specifically, the staged grouting pressure control equations include: , in, For a moment Time Grouting pressure at each grouting stage, This is the design value for the maximum grouting pressure. This refers to the total number of grouting stages. Grouting is carried out in three stages to ensure uniform filling of the grout. The grouting pressure growth coefficient (dimensionless) controls the gradient growth rate of grouting pressure at each stage. For a moment The difference in normal stress at the splicing interface For a moment Axial tensile strength of new concrete The interface state adjustment factor (dimensionless) comprehensively considers the influence of interface roughening quality, wetting state, and bonding layer pouring quality on grouting effect.

[0035] The grouting pressure gradually increases in three stages to ensure that the grout fully penetrates from the inside out.

[0036] Step 4: Calculate the dynamic prestress compensation based on the differential deformation compatibility index and the differential normal stress at the splicing interface, and implement tensioning in stages by setting adjustable prestressed anchors laterally in the new and old splicing strips. Specifically, the calculation of dynamic prestress compensation includes: , Step 5: Conduct full-cycle crack width monitoring on the splicing interface, calculate the monitoring feedback adjustment coefficient based on the ratio of the monitored crack width to the allowable crack width limit of the splicing interface, and adaptively correct the dynamic prestress compensation amount based on the monitoring feedback adjustment coefficient.

[0037] Prestressed aging amplification factor Calculate using the following formula: , in, For a moment Prestressing aging amplification factor, For a moment Dynamic prestress compensation amount The effective area of ​​the interface between the old and new parts. For a moment The difference in normal stress at the splicing interface The critical compatibility index (dimensionless) is when The time-difference deformation is within an acceptable range, and no active prestressing compensation is required. This is the prestress amplification sensitivity coefficient (dimensionless). The larger the value, the more rapidly the prestress compensation increases when the compatibility index exceeds the critical value. The prestress aging morphology index (dimensionless) controls the peak shape of the prestress compensation over time. The characteristic time parameter for prestress compensation (dimensionless, corresponding to...) The prestress demand caused by differential deformation reaches its peak at approximately 180 days and then gradually converges. When the interface is activated, This is a normalized reference time.

[0038] Specifically, calculate the monitoring feedback adjustment coefficient. : , in, For a moment Real-time monitoring and feedback adjustment coefficient The maximum adjustment range coefficient (dimensionless) is specified, and the adaptive adjustment amount is limited to no more than 60% of the initial compensation amount. For mathematical constants, To adjust the sensitivity coefficient (dimensionless), which controls the response rate of the adjustment range to the degree of crack width exceeding the limit, a larger value indicates a faster increase in the adjustment range after exceeding the limit. For a moment The width of the crack at the splicing interface was monitored in real time. To limit the allowable width of cracks at the splicing interface; time Dynamic prestress compensation amount after adaptive correction for: .

[0039] Preferably, the adaptive control cycle does not exceed 7 days; updates must be made synchronously before each control. , , The calculated value is used to reassess the interface security status based on the latest value. This applies when there are two consecutive control cycles. All in When within the specified range, the control period can be extended to 14 days.

[0040] Example 2 like Figure 2 As shown in the figure, this embodiment proposes a coordinated control system for shrinkage and creep of the old and new splice strips in the reconstruction and expansion of bridges, including: The first calculation module is used to obtain the characteristic parameters of new and old concrete, and calculate the shrinkage strain of new concrete, shrinkage strain of old concrete, effective elastic modulus of new concrete, creep coefficient of new concrete and creep coefficient of old concrete at any time, so as to calculate the differential deformation compatibility index that comprehensively reflects the difference in shrinkage, creep and temperature. The interface activation time determination module is used to calculate the differential deformation compatibility index and the effective elastic modulus of new concrete, calculate the differential normal stress at the splicing interface, and jointly determine the interface activation time by the stiffness matching criterion and the interface strength safety criterion, taking the earliest time when both criteria are satisfied as the interface activation time. The grouting module is used to sequentially perform interface mechanical roughening treatment, interface bonding concrete pouring, and staged grouting after determining the grouting pressure of each stage according to the staged grouting pressure control equation when the interface activation time is reached. The tensioning module is used to calculate the dynamic prestress compensation based on the differential deformation compatibility index and the differential normal stress at the splice interface, and to implement tensioning in stages through adjustable prestressed anchor cables set laterally in the new and old splice strips. The correction module is used to monitor the crack width of the splicing interface throughout the entire cycle. It calculates the monitoring feedback adjustment coefficient based on the ratio of the monitored crack width of the splicing interface to the allowable crack width limit of the splicing interface, and performs adaptive correction on the dynamic prestress compensation amount based on the monitoring feedback adjustment coefficient.

[0041] Since Example 2 is based on Example 1, it will not be described again.

[0042] Example 3 This invention also proposes a storage medium storing multiple instructions for implementing the aforementioned method for coordinated control of shrinkage and creep at the joint between old and new sections of an expanded or renovated bridge.

[0043] Optionally, in this embodiment, the storage medium may be located in any computer terminal in a group of computer terminals in a computer network, or in any mobile terminal in a group of mobile terminals.

[0044] Optionally, in this embodiment, the storage medium is configured to store program code for performing the method steps of Embodiment 1.

[0045] Example 4 This invention also proposes an electronic device, such as... Figure 3 As shown, it includes a processor and a storage medium connected to the processor. The storage medium stores multiple instructions, which can be loaded and executed by the processor to enable the processor to execute the aforementioned method for coordinated control of shrinkage and creep of the new and old splice strips of an expanded bridge.

[0046] Specifically, the electronic device in this embodiment can be a computer terminal, which may include one or more processors and a storage medium.

[0047] The storage medium can be used to store software programs and modules, such as the coordinated control method for shrinkage and creep of the old and new splice strips of a bridge in this embodiment of the invention. The corresponding program instructions / modules are executed by the processor through the software programs and modules stored in the storage medium, thereby performing various functional applications and data processing, thus realizing the aforementioned coordinated control method for shrinkage and creep of the old and new splice strips of a bridge in this embodiment. The storage medium may include high-speed random access storage media, and may also include non-volatile storage media, such as one or more magnetic storage systems, flash memory, or other non-volatile solid-state storage media. In some instances, the storage medium may further include storage media remotely configured relative to the processor, which can be connected to the terminal via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0048] The processor can execute the method steps of Embodiment 1 by calling the information and application stored in the storage medium through the transmission system.

[0049] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0050] In the several embodiments provided by this invention, it should be understood that the disclosed technical content can be implemented in other ways. The system embodiments described above are merely illustrative; for example, the division of 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, indirect coupling or communication connection between units or modules, and may be electrical or other forms.

[0051] 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.

[0052] 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.

[0053] If the integrated 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, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes: USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, optical disks, and other media capable of storing program code.

[0054] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for coordinated control of shrinkage and creep at the joint between old and new sections of a reconstructed or expanded bridge, characterized in that, include: Step 1: Obtain the characteristic parameters of new and old concrete, and calculate the shrinkage strain of new concrete, shrinkage strain of old concrete, effective elastic modulus of new concrete, creep coefficient of new concrete and creep coefficient of old concrete at any time, so as to calculate the differential deformation compatibility index that comprehensively reflects the difference in shrinkage, creep and temperature. Step 2: Calculate the differential deformation compatibility index and the effective elastic modulus of the new concrete, calculate the differential normal stress at the splicing interface, and determine the interface activation time by combining the stiffness matching criterion and the interface strength safety criterion. Take the earliest time when both criteria are satisfied at the same time as the interface activation time. Step 3: When the interface activation time is reached, mechanical roughening of the interface and concrete pouring of the interface are carried out in sequence. Then, the grouting pressure of each stage is determined according to the staged grouting pressure control equation and staged grouting is carried out. Step 4: Calculate the dynamic prestress compensation based on the differential deformation compatibility index and the differential normal stress at the splicing interface, and implement tensioning in stages by setting adjustable prestressed anchors laterally in the new and old splicing strips. Step 5: Conduct full-cycle crack width monitoring on the splicing interface, calculate the monitoring feedback adjustment coefficient based on the ratio of the monitored crack width to the allowable crack width limit of the splicing interface, and adaptively correct the dynamic prestress compensation amount based on the monitoring feedback adjustment coefficient.

2. The method for coordinated control of shrinkage and creep in the splice zone between old and new bridges in reconstruction and expansion as described in claim 1, characterized in that, Differential deformation compatibility index includes: ， in, For a moment The time-varying deformation compatibility index For a moment The difference in shrinkage strain between old and new concrete at that time For a moment The difference in creep coefficient between old and new concrete at that time For a moment The temperature difference between the old and new concrete at that time For reference shrinkage strain, For reference creep coefficient, For reference temperature difference, For contraction weighting coefficients, This is the creep weighting coefficient. This is the temperature weighting coefficient.

3. The method for coordinated control of shrinkage and creep at the joint between old and new sections of a reconstructed or expanded bridge as described in claim 1, characterized in that... Calculating the shrinkage strain of new concrete includes: ， in, For a moment Shrinkage strain of new concrete at that time This represents the ultimate shrinkage strain of the new concrete. This is the correction factor for relative humidity. This is the correction factor for the strength of the new concrete. This is the shrinkage rate coefficient of the new concrete. This marks the completion time of the new standard curing process for concrete. For normalized reference time, This is the shrinkage morphology index for new concrete.

4. The method for coordinated control of shrinkage and creep at the joint between old and new sections of a reconstructed or expanded bridge as described in claim 1, characterized in that... Calculating the creep coefficient of new concrete includes: ， in, Self-loading age of new concrete At that time The new concrete creep coefficient, This represents the ultimate creep coefficient of the new concrete foundation. To determine the characteristic compressive strength of new concrete The new concrete strength reduction factor is a parameter. This refers to the creep development pattern index. To load the age-related influence coefficient, To load the age decay index, The age at which new concrete is first subjected to load. This is a normalized reference time.

5. The method for coordinated control of shrinkage and creep at the joint between old and new sections of a reconstructed or expanded bridge as described in claim 2, characterized in that... The stiffness matching criterion is: ， The interface strength safety criteria are: ， in, For a moment Effective elastic modulus of modern concrete The elastic modulus of the old concrete. This is the stiffness activation threshold coefficient. The compatibility index is the sensitivity coefficient. For a moment The time-varying deformation compatibility index For a moment Axial tensile strength of new concrete For the interface tensile safety factor, For a moment The difference in normal stress at the splicing interface.

6. The method for coordinated control of shrinkage and creep in the splice zone between old and new bridges as described in claim 1, characterized in that, The staged grouting pressure control equations include: ， in, For a moment Time Grouting pressure at each grouting stage This is the design value for the maximum grouting pressure. This represents the total number of grouting stages. The grouting pressure growth coefficient is... For a moment The difference in normal stress at the splicing interface For a moment Axial tensile strength of new concrete This is a factor for adjusting the interface state.

7. The method for coordinated control of shrinkage and creep at the joint between old and new sections of a reconstructed or expanded bridge as described in claim 2, characterized in that... The calculation of dynamic prestress compensation includes: ， Among them, the prestressing aging amplification factor Calculate using the following formula: ， in, For a moment Prestress aging amplification factor, For a moment Dynamic prestress compensation amount The effective area of ​​the interface between the old and new parts. For a moment The difference in normal stress at the splicing interface This is the critical compatibility index. This is the prestress amplification sensitivity coefficient. The prestressed aging morphology index, For prestress compensation characteristic time parameters, When the interface is activated, This is a normalized reference time.

8. The method for coordinated control of shrinkage and creep at the joint between old and new sections of a reconstructed or expanded bridge as described in claim 7, characterized in that... Calculate the monitoring feedback adjustment coefficient : ， in, For a moment Real-time monitoring and feedback adjustment coefficient The maximum adjustment range coefficient. For mathematical constants, To adjust the sensitivity coefficient, For a moment The width of the crack at the splicing interface was monitored in real time. To limit the allowable width of cracks at the splicing interface; time Dynamic prestress compensation amount after adaptive correction for: .

9. A coordinated control system for shrinkage and creep of the splice zone between old and new sections of a renovated or expanded bridge, characterized in that, include: The first calculation module is used to obtain the characteristic parameters of new and old concrete, and calculate the shrinkage strain of new concrete, shrinkage strain of old concrete, effective elastic modulus of new concrete, creep coefficient of new concrete and creep coefficient of old concrete at any time, so as to calculate the differential deformation compatibility index that comprehensively reflects the difference in shrinkage, creep and temperature. The interface activation time determination module is used to calculate the differential deformation compatibility index and the effective elastic modulus of new concrete, calculate the differential normal stress at the splicing interface, and jointly determine the interface activation time by the stiffness matching criterion and the interface strength safety criterion, taking the earliest time when both criteria are satisfied as the interface activation time. The grouting module is used to sequentially perform interface mechanical roughening treatment, interface bonding concrete pouring, and staged grouting after determining the grouting pressure of each stage according to the staged grouting pressure control equation when the interface activation time is reached. The tensioning module is used to calculate the dynamic prestress compensation based on the differential deformation compatibility index and the differential normal stress at the splice interface, and to implement tensioning in stages through adjustable prestressed anchor cables set laterally in the new and old splice strips. The correction module is used to monitor the crack width of the splicing interface throughout the entire cycle. It calculates the monitoring feedback adjustment coefficient based on the ratio of the monitored crack width of the splicing interface to the allowable crack width limit of the splicing interface, and performs adaptive correction on the dynamic prestress compensation amount based on the monitoring feedback adjustment coefficient.

10. A coordinated control system for shrinkage and creep of the new and old splice zone of an expanded or renovated bridge as described in claim 9, characterized in that, The differential deformation compatibility index includes: the differential deformation compatibility index mentioned in step two. Calculate using the following formula: ， in, For a moment The time-varying deformation compatibility index For a moment The difference in shrinkage strain between old and new concrete at that time For a moment The difference in creep coefficient between old and new concrete at that time For a moment The temperature difference between the old and new concrete at that time For reference shrinkage strain, For reference creep coefficient, For reference temperature difference, For contraction weighting coefficients, This is the creep weighting coefficient. This is the temperature weighting coefficient.

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