Intelligent reinforcing method and system for reinforced concrete column based on temperature change and creep compensation

Abstract

The application relates to the technical field of structure reinforcement, and discloses a steel reinforced concrete column intelligent reinforcement method and system based on temperature variation and creep compensation. The method comprises the following steps: collecting interlayer displacement time series and pressure time series by a multi-source sensing unit, fitting the interlayer displacement time series by a sliding window least square to obtain a deformation acceleration sequence, determining a pre-storage compensation target quantity according to the difference between the linear extrapolation zero-crossing moment of the deformation acceleration sequence and the current moment and a shape memory alloy compensation allowance, switching to a dormant mode after driving an electromagnetic actuator to execute single pre-storage compensation, and correcting a trigger threshold value by accumulating an interface shear stress increment to the interface fatigue damage degree. The application improves the cooperative control level of the prestress stability and the interface fatigue life of the steel reinforced concrete column reinforcement system in the whole service period.

Description

Technical Field

[0001] This application relates to the field of structural reinforcement technology, and in particular to an intelligent reinforcement method and system for reinforced concrete columns based on temperature change and creep compensation. Background Technology

[0002] Reinforced concrete columns are core components in industrial and civil building structures that bear vertical loads and horizontal seismic forces. During long-term service, their load-bearing capacity continuously declines due to factors such as concrete creep, material aging, and environmental temperature cycles. Prestressed concrete reinforced polymer (FRP) confined reinforcement technology is currently one of the mainstream methods for repairing and improving the performance of existing reinforced concrete column structures. Existing technologies typically use permanent magnets to provide fixed prestress or use threshold-response PID control to drive electromagnetic actuators for compensation. Simultaneously, Ti-Ni-Nb shape memory alloy temperature-sensitive compensation components are used to passively compensate for prestress losses caused by temperature fluctuations. Multi-source sensing units collect prestress and deformation data in real time and upload them to the control module, which then determines whether to trigger the actuator.

[0003] However, the control logic in the existing technology uses the measured prestress value being lower than the design threshold as the compensation trigger condition, which is essentially a post-event response after the loss has occurred. The actuator continuously responds to the slight fluctuations in the pressure timing throughout the entire service life, frequently performing small compensation actions. Each actuation injects a cyclic stress increment into the welding interface between the FRP fiber bundle and the load-bearing steel plate. As the number of compensations accumulates, the interface fatigue damage continues to increase, eventually leading to fatigue debonding failure of the FRP-metal welding interface. The existing control strategy is completely unaware of the accumulation process of interface damage. The triggering timing and triggering amplitude of the compensation action are decoupled from the interface fatigue state, making it impossible to form a synergistic constraint between prestress compensation requirements and interface durability.

[0004] The fundamental reason for the frequent response of the actuator is that the existing technology has failed to extract the information on the timing of compensation from the phased laws of creep deformation. Creep deformation already shows a trend of deformation acceleration towards the acceleration phase at the end of the steady-state phase. If the pre-stored compensation can be applied in full before this transition occurs, the number of actuations in a single service cycle can be reduced from the source, thereby reducing the injection rate of interface fatigue damage. However, once the number of actuations is reduced, the compensation magnitude increases accordingly. How to incorporate the incremental interface shear stress generated by a single compensation into the decision-making basis of the triggering strategy for the next cycle constitutes a new technical problem that needs to be solved. Summary of the Invention

[0005] This application provides a smart reinforcement method and system for reinforced concrete columns based on temperature change and creep compensation. It solves the problems in existing prestressed FRP reinforcement systems, such as the continuous accumulation of fatigue damage at the FRP-metal weld interface caused by frequent post-response actuation, and the complete decoupling of compensation control strategies from the interface durability state. It improves the coordinated management level of prestress stability and interface fatigue life of the reinforced concrete column reinforcement system throughout its service life.

[0006] Firstly, this application provides a smart reinforcement method for reinforced concrete columns based on temperature change and creep compensation, the smart reinforcement method for reinforced concrete columns based on temperature change and creep compensation includes: Step S1: The interlayer displacement time series and pressure time series are collected by the multi-source sensing unit to obtain the creep monitoring dataset; Step S2: The interlayer displacement time series in the creep monitoring dataset is fitted with a sliding window least squares to obtain the deformation acceleration sequence. When the difference between the linear extrapolation zero crossover time of the deformation acceleration sequence and the current time is not greater than the trigger threshold and the fitting confidence meets the preset conditions, the pre-stored compensation target amount is determined by the difference between the pressure time series and the upper limit of the prestress design and the shape memory alloy compensation margin. Step S3: Drive the electromagnetic actuator to perform a single pre-stored compensation according to the pre-stored compensation target amount, and then switch to sleep mode. The Ti-Ni-Nb shape memory alloy temperature change compensation component will bear the slight fluctuation of the pressure timing. Step S4: The incremental interface shear stress generated by this compensation is added to the interface fatigue damage degree, and the trigger threshold for the next cycle is corrected based on the interface fatigue damage degree.

[0007] Secondly, this application provides an intelligent reinforcement system for reinforced concrete columns based on temperature change and creep compensation, the intelligent reinforcement system for reinforced concrete columns based on temperature change and creep compensation comprising: The acquisition module is used to acquire interlayer displacement time series and pressure time series by multi-source sensing units to obtain creep monitoring dataset; The fitting module is used to obtain the deformation acceleration sequence by fitting the interlayer displacement time series in the creep monitoring dataset through a sliding window least squares. When the difference between the linear extrapolation zero crossover time of the deformation acceleration sequence and the current time is not greater than the trigger threshold and the fitting confidence meets the preset conditions, the pre-stored compensation target amount is determined by the difference between the pressure time series and the upper limit of the prestress design and the shape memory alloy compensation margin. The switching module is used to drive the electromagnetic actuator to perform a single pre-stored compensation according to the pre-stored compensation target amount and then switch to the sleep mode, with the Ti-Ni-Nb shape memory alloy temperature change compensation component bearing the slight fluctuations in the pressure timing. The triggering module is used to accumulate the interface shear stress increment generated by this compensation to the interface fatigue damage degree, and to correct the triggering threshold for the next cycle based on the interface fatigue damage degree.

[0008] Thirdly, a smart reinforcement device for reinforced concrete columns based on temperature change and creep compensation is provided, comprising: a memory and at least one processor, wherein the memory stores instructions; the at least one processor invokes the instructions in the memory to cause the smart reinforcement device for reinforced concrete columns based on temperature change and creep compensation to execute the aforementioned smart reinforcement method for reinforced concrete columns based on temperature change and creep compensation.

[0009] Fourthly, a computer-readable storage medium is provided, wherein instructions are stored therein, which, when executed on a computer, cause the computer to perform the above-described intelligent reinforcement method for reinforced concrete columns based on temperature change and creep compensation.

[0010] The technical solution provided in this application continuously collects interlayer displacement and pressure time series data through multi-source sensing units to construct a creep monitoring dataset. This allows the creep deformation state and prestress level to be synchronously characterized under the same time reference, solving the problem in existing technologies where creep deformation and prestress data are isolated and cannot be jointly used to determine the reinforcement status. Based on this, the interlayer displacement time series is extracted into a deformation acceleration sequence using sliding window least squares fitting. The difference between the linear extrapolation zero-crossing moment of the deformation acceleration sequence and the current moment is used as the trigger criterion, enabling the compensation action to be triggered in advance before the creep transitions from the steady-state stage to the acceleration stage. This fundamentally changes the post-event response logic in existing technologies, which uses prestress below a threshold as the trigger condition. The pre-stored compensation target amount is determined by combining the difference between the pressure time series and the upper limit of the prestress design, as well as the shape memory alloy compensation margin. This quantifies and utilizes the passive compensation capability of Ti-Ni-Nb shape memory alloy under different temperature conditions, avoiding repeated compensation by the electromagnetic actuator for the temperature fluctuation portion that the SMA can already handle. This achieves collaborative division of labor between the two compensation mechanisms at the computational level.

[0011] Based on the pre-stored compensation target, the electromagnetic actuator performs a single pre-stored compensation and immediately switches to sleep mode. The Ti-Ni-Nb shape memory alloy temperature-varying compensation component absorbs the slight fluctuations in the pressure timing, transforming the electromagnetic actuator from a continuous high-frequency response to a single large-scale pre-stored operation. This physically eliminates the root cause of frequent actuator actions injecting cyclic stress increments into the FRP-metal weld interface. Furthermore, the interface shear stress increment generated by each compensation is accumulated to the interface fatigue damage degree, and the trigger threshold for the next cycle is adjusted in intervals based on the interface fatigue damage degree. This allows the compensation strategy to adaptively adjust as the interface damage state evolves, forming a closed-loop control mechanism with interface durability as the constraint boundary. This solves the core technical contradiction in existing technologies where the compensation control strategy is completely decoupled from the long-term damage state of the structural interface, making it impossible to coordinate the control of prestress stability and interface fatigue life throughout the entire service life. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of an embodiment of the intelligent reinforcement method for reinforced concrete columns based on temperature change and creep compensation in this application. Figure 2 This is a schematic diagram illustrating the relationship between the compensation margin and equivalent prestress compensation of Ti-Ni-Nb shape memory alloy as a function of ambient temperature in the embodiments of this application. Detailed Implementation

[0014] This application provides an intelligent reinforcement method and system for reinforced concrete columns based on temperature change and creep compensation. The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms "comprising" or "having" and any variations thereof are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0015] For ease of understanding, the specific process of the embodiments of this application is described below. Please refer to [link / reference]. Figure 1 One embodiment of the intelligent reinforcement method for reinforced concrete columns based on temperature change and creep compensation in this application includes: Step S1: The interlayer displacement time series and pressure time series are collected by the multi-source sensing unit to obtain the creep monitoring dataset; Specifically, the multi-source sensing unit consists of a pressure sensor and a displacement sensor. The pressure sensor is embedded between the electromagnetic actuator and the composite reinforcement layer to collect real-time prestress values ​​of the composite reinforcement layer. The displacement sensor is positioned at the weld interface between the composite reinforcement layer and the load-bearing steel plate to collect interlayer deformation at this interface. Both types of sensors continuously output data at a fixed sampling interval of 50ms. The 50ms sampling interval is determined by the time-varying rate of creep deformation—the creep deformation rate of the concrete column reinforcement system is at its fastest, approximately on the order of 0.001mm per second. The 50ms sampling interval is sufficient to capture minute changes in the deformation rate without undersampling distortion. The collected pressure and displacement value sequences, after being aligned with timestamps, are collectively referred to as the creep monitoring dataset. The displacement value sequence indexed by time is the interlayer displacement time series, and the pressure value sequence indexed by time is the pressure time series.

[0016] Step S2: The interlayer displacement time series in the creep monitoring dataset is fitted with a sliding window least squares to obtain the deformation acceleration sequence. When the difference between the linear extrapolation zero crossover time of the deformation acceleration sequence and the current time is not greater than the trigger threshold and the fitting confidence meets the preset conditions, the pre-stored compensation target amount is determined by the difference between the pressure time series and the upper limit of the prestress design and the shape memory alloy compensation margin. Specifically, the deformation acceleration sequence is extracted from the inter-layer displacement time series, and the zero-crossing moment of the linear extrapolation of the deformation acceleration sequence is used as the trigger criterion. The deformation acceleration sequence refers to the second-order rate of change sequence obtained after performing two sliding window least squares fittings on the inter-layer displacement time series. Physically, it represents the rate of change of the deformation rate at the interface of the composite reinforcement layer. When this sequence changes from a negative trend to a positive trend, it indicates that creep has entered the acceleration phase from the steady-state phase. The zero-crossing moment of the linear extrapolation refers to the predicted time corresponding to the linear extrapolation of the recent trend of the deformation acceleration sequence to zero. The difference between this time and the current time is the remaining prediction time. The trigger threshold is set to 3600s, meaning that compensation is triggered one hour before creep enters the acceleration phase, allowing sufficient time for current ramp-up and verification. The preset condition for the fitting confidence level is that the regression fitting determination coefficient is not less than 0.85. This value ensures that the prediction results of the linear extrapolation have statistical reliability. If the value is lower than this, the prediction results are unstable, and compensation is not triggered. The shape memory alloy compensation margin is calculated from the relative position of the current temperature of the Ti-Ni-Nb alloy within its phase transformation temperature range. It reflects the remaining releaseable passive compensation capacity of the alloy. After being expressed in equivalent prestress units, it is deducted from the pre-stored compensation target amount to avoid over-compensation of the electromagnetic actuator.

[0017] Step S3: After driving the electromagnetic actuator to perform a single pre-stored compensation based on the pre-stored compensation target amount, switch to sleep mode, and the Ti-Ni-Nb shape memory alloy temperature change compensation component bears the slight fluctuations in the pressure timing. Specifically, the dormant mode refers to the operating state in which the electromagnetic actuator, after a single pre-charge compensation, reduces the input current to 0.3 times the target drive current and maintains this current value, no longer responding to minor fluctuations in pressure timing. The 0.3 times holding current is sufficient to maintain the basic magnetic flux in the actuator's magnetic circuit, preventing the composite reinforcement layer from suddenly releasing force due to the complete disappearance of the magnetic field, while minimizing the actuator's operating frequency. During the dormant mode, the Ti-Ni-Nb shape memory alloy temperature-dependent compensation component passively responds to minor fluctuations in pressure timing within a pre-stress design threshold range of ±3.2 MPa, relying on its own reversible phase deformation caused by temperature changes. This range is determined by converting the maximum reversible deformation of the Ti-Ni-Nb alloy in the temperature range of -30℃ to 70℃ into an equivalent pre-stress.

[0018] Step S4: Add the incremental interface shear stress generated by this compensation to the interface fatigue damage degree, and correct the trigger threshold for the next cycle based on the interface fatigue damage degree. Specifically, the interfacial shear stress increment is calculated by combining the difference in pressure timing before and after this single pre-storage compensation with the equivalent stress area of ​​the composite reinforcement layer, the number of dovetail axial anchoring grooves, and the number and equivalent shear length of the weld points. This reflects the local shear stress amplitude injected into the FRP-metal welded interface by this compensation action. The interface fatigue damage degree is calculated using the Palmgren-Miner linear damage accumulation criterion, which involves summing the interfacial shear stress increments generated by each compensation and dividing by the fatigue shear strength of the FRP-metal welded interface to obtain a dimensionless cumulative damage ratio. The trigger threshold is corrected in three intervals based on the interface fatigue damage degree: when the damage degree is no greater than 0.6, the trigger threshold remains unchanged at 3600s; when the damage degree is greater than 0.6 but no greater than 0.8, the trigger threshold is extended to 5400s, delaying the next compensation trigger and correspondingly reducing the single compensation amplitude; when the damage degree is greater than 0.8, the trigger threshold is shortened to 1800s and a warning signal is output. At this time, a smaller compensation amplitude and a higher trigger frequency replace a large single compensation, keeping the stress impact on the interface of each compensation at a lower level. The boundary values ​​of 0.6 and 0.8 for the three intervals are set according to the Palmgern-Miner criterion, which states that the probability of interface failure increases sharply when the damage degree is close to 1.0. Below 0.6, the interface is in the safe zone; 0.6 to 0.8 is the warning zone; and above 0.8 is the high-risk zone.

[0019] In one specific embodiment, step S1 includes: With a fixed sampling interval of 50ms, the pressure sensor continuously reads the contact pressure between the composite reinforcement layer and the electromagnetic actuator to obtain the pressure sampling sequence; With a fixed sampling interval of 50ms, the displacement sensor continuously reads the interlaminar deformation at the interface between the composite reinforcement layer and the load-bearing steel plate to obtain the displacement sampling sequence; Using timestamps as indices, the pressure sampling sequence and displacement sampling sequence are time-aligned and concatenated to obtain a creep monitoring dataset containing interlayer displacement time series and pressure time series.

[0020] Specifically, a pressure sensor is embedded between the electromagnetic actuator and the composite reinforcement layer, collecting real-time prestress values ​​of the composite reinforcement layer under the tension of the electromagnetic actuator. This value directly reflects the current prestress level of the reinforcement system. A displacement sensor is positioned at the weld interface r between the composite reinforcement layer and the load-bearing steel plate, collecting the interlayer relative deformation at this interface under creep. This deformation accumulates continuously with the creep process and exhibits a phased rate change pattern. Both types of sensors use a fixed sampling interval of 50ms. This value is set based on the fact that the maximum interfacial creep deformation rate of the concrete column reinforcement system is approximately 0.001mm per second. The deformation increment within a single sampling cycle at a 50ms interval is approximately 0.00005mm, which is within the detectable range of the displacement sensor's resolution of 0.001mm. This ensures that subtle changes in deformation rate are captured without redundant data accumulation due to excessively short sampling intervals.

[0021] The pressure sampling sequence and displacement sampling sequence are time-aligned and stitched together using timestamps as indices. This ensures that the pressure and displacement values ​​at the same moment strictly correspond in the creep monitoring dataset, avoiding misalignment of the subsequent deformation acceleration sequence and pressure time sequence on the time axis due to asynchronous reading errors between the two sensors. After stitching, the interlayer displacement time sequence in the creep monitoring dataset is the interlayer deformation sequence indexed by time, and the pressure time sequence is the prestress numerical sequence indexed by time.

[0022] In one specific embodiment, step S2 involves obtaining a deformation acceleration sequence by performing a sliding window least squares fitting on the interlayer displacement time series in the creep monitoring dataset, including: Using 11 consecutive sampling points as a sliding window, the time series of inter-story displacements is fitted with least squares linearly, and the slope obtained from the fitting is used as the deformation rate value at the center of the corresponding window to obtain the deformation rate sequence. Using the deformation rate sequence as input, least squares linear fitting is performed again with the same window length. The slope obtained from the fitting is used as the deformation acceleration value at the center of the corresponding window to obtain the deformation acceleration sequence. The deformation acceleration sequence is refreshed every 50 new data points collected and stored in a circular buffer.

[0023] Specifically, the sliding window length is set to 11 consecutive sampling points, corresponding to a time span of 550 ms. This window length is determined based on the following: if the window is too short, the measurement noise of a single sampling point significantly interferes with the slope fitting result, leading to drastic fluctuations in the deformation rate sequence; if the window is too long, the fitted slope responds slowly to real-time changes in the deformation rate, failing to reflect the transition of the creep stage in a timely manner. The interlayer displacement time series is fitted using a least-squares linear fit with 11 sampling points as the window. The slope of the fitted line physically represents the average rate of change of the interlayer deformation over time within the 550 ms time period. This slope value is used as the deformation rate value at the center of the window, and the deformation rate sequence is obtained by sliding point by point. The least-squares linear fit is then repeated with the deformation rate sequence as input and the same 11-point window length. The fitted slope reflects the rate of change of the deformation rate itself over time, i.e., the deformation acceleration value. The deformation acceleration sequence is obtained by sliding point by point. The deformation acceleration sequence numerically corresponds to the second-order rate of change of the inter-layer displacement time series. When the sequence continuously approaches zero from a negative value, it indicates that creep has entered the steady-state stage from the initial deceleration stage; when the sequence changes from a negative trend to a positive trend, it indicates that creep is about to enter the acceleration stage.

[0024] The deformation acceleration sequence is refreshed every 50 new data points, corresponding to a refresh cycle of 2500ms. This refresh frequency is determined by the time scale of the creep stage transition—the transition process from steady-state creep to accelerated creep in a reinforced concrete column system typically lasts from tens of minutes to several hours, and a 2500ms refresh cycle provides sufficient temporal resolution at this time scale. The circular buffer refers to a fixed-length continuous storage space in the memory. Newly calculated deformation acceleration values ​​are continuously written to this space. When the storage space is full, new data overwrites the oldest data written at the beginning, always retaining the deformation acceleration sequence within the most recent period for subsequent linear regression fitting. Its maximum storage length is set to 72 hours of rolling data to cover the typical duration of the steady-state creep stage.

[0025] Figure 2 This is a schematic diagram illustrating the relationship between the compensation margin and equivalent prestress compensation of Ti-Ni-Nb shape memory alloy as a function of ambient temperature in the embodiments of this application. Figure 2In the figure, the horizontal axis represents the ambient temperature, the left side of the vertical axis represents the compensation margin of the shape memory alloy, and the right side of the vertical axis represents the equivalent prestress compensation amount. The shaded area represents the available compensation strain margin of the Ti-Ni-Nb shape memory alloy at the current temperature. The solid line represents the linear change curve of the compensation margin with temperature, and the dashed line represents the equivalent prestress compensation amount obtained by converting the compensation margin according to the alloy's equivalent elastic modulus, the cross-sectional area of ​​the temperature change compensation component, and the equivalent stress area of ​​the composite reinforcement layer. The values ​​of each key temperature point marked in the figure show that as the ambient temperature rises from -30℃ to 70℃, the proportion of Ti-Ni-Nb alloy that has completed the phase transformation increases linearly, and the remaining releaseable compensation strain margin decreases linearly from 8% to 0. The corresponding equivalent prestress compensation amount decreases linearly from the maximum value to zero and is deducted from the pre-stored compensation target amount in the form of equivalent prestress compensation amount, so that the electromagnetic actuator can bear the accurate compensation range under different temperature conditions.

[0026] In one specific embodiment, step S2, when the difference between the linear extrapolation zero-crossing time of the deformation acceleration sequence and the current time is not greater than the trigger threshold and the fitting confidence meets the preset condition, includes: Take the 60 most recent calculated values ​​from the deformation acceleration sequence, and perform linear regression fitting on the deformation acceleration sequence and the time series to obtain the regression slope and regression intercept. Substituting the regression slope and regression intercept into the zero-value equation, we obtain the linear extrapolation zero-crossing time of the deformation acceleration sequence. The difference between the linear extrapolation zero-crossing time and the current time is used to obtain the predicted remaining time. When the predicted remaining time is not greater than the trigger threshold and the regression fitting determination coefficient is not less than 0.85, the pre-stored compensation preparation signal is triggered.

[0027] Specifically, the 60 most recent calculated values ​​from the deformation acceleration sequence were selected as regression samples, corresponding to a time span of 150 seconds. The selection of these 60 values ​​was based on the following: too small a sample size results in linear regression fitting significantly affected by local noise, leading to unstable regression slopes; too large a sample size results in an excessively long regression window coverage period, failing to reflect recent trend changes in the deformation acceleration sequence in a timely manner. Least squares linear regression was performed on the data pairs consisting of these 60 deformation acceleration values ​​and their corresponding timestamps. The fitting results are expressed by two parameters: the regression slope and the regression intercept. The regression slope reflects the linear trend of the deformation acceleration sequence within the past 150 seconds, while the regression intercept reflects the intercept value at the starting point of this linear trend on the time axis. The zero-value equation refers to the equation obtained by setting the dependent variable in the above linear regression equation to zero and solving the equation corresponding to the independent variable at the given time. The regression intercept is divided by the negative number of the regression slope to obtain the linear extrapolation zero crossover time. The physical meaning of this time is the predicted time when the deformation acceleration rises from the current negative trend to zero, based on the linear extrapolation of the current deformation acceleration sequence. This corresponds to the predicted node when creep enters the acceleration phase from the steady state phase.

[0028] The predicted remaining time is obtained by subtracting the zero-crossing moment from the current moment during linear extrapolation. The trigger threshold is set at 3600s, based on the fact that the linear ramp-up process of the target drive current of the electromagnetic actuator takes 120s. Including pressure verification, state switching, and safety margin, triggering one hour before creep enters the acceleration phase ensures complete execution of pre-stored compensation. A regression fit determination coefficient of not less than 0.85 is used as a preset condition for the fit confidence level. The determination coefficient reflects the goodness of fit of the linear regression model to the recent trend of the deformation acceleration sequence, and its value ranges from 0 to 1. A value below 0.85 indicates that the recent trend linearity of the deformation acceleration sequence is not significant, the reliability of the linear extrapolation result is insufficient, and the pre-stored compensation preparation signal is not triggered. A value of not less than 0.85 indicates that the linear extrapolation has statistically significant credibility, triggering the pre-stored compensation preparation signal and driving the subsequent calculation of the pre-stored compensation target amount and the execution process of the electromagnetic actuator.

[0029] In one specific embodiment, step S2, determining the pre-stress compensation target amount based on the difference between the pressure timing and the upper limit of the prestress design and the shape memory alloy compensation margin, includes: The prestress gap is obtained by calculating the difference between the current prestress value in the pressure time series and the upper limit of the prestress design. Based on the relative position of the current temperature within the phase transformation temperature range of the Ti-Ni-Nb shape memory alloy, the maximum bidirectional memory strain of the shape memory alloy is proportionally reduced to obtain the shape memory alloy compensation margin, and the shape memory alloy compensation margin is converted into the equivalent prestress compensation amount. The prestressing gap is added to the safety reserve and then subtracted from the equivalent prestressing compensation to obtain the prestressing compensation target.

[0030] Specifically, the upper limit of the prestress design is taken as 1.05 times the prestress design threshold. This ratio is set based on the fact that the safety factor of the FRP fiber bundle in the composite reinforcement layer under short-term overload conditions is not less than 1.05. Exceeding this upper limit will cause irreversible creep damage to the fiber bundle, while below this upper limit, the pre-stored compensation amount is insufficient to cover the natural decay of prestress during the subsequent creep steady-state period. The prestress gap is the difference between the upper limit of the prestress design and the current prestress value in the pressure time series, reflecting the gap between the current prestress level and the pre-stored target value. The phase transformation temperature range of Ti-Ni-Nb shape memory alloy is -30 degrees Celsius to 70 degrees Celsius. The relative position of the current temperature within this range is calculated by subtracting the lower limit of the range from the current temperature and dividing by the range span, with a value ranging from 0 to 1. This relative position value reflects the proportion of phase transformation that the alloy has completed. The shape memory alloy compensation margin is obtained by multiplying the maximum bidirectional memory strain of 8% by the complement of the relative position, which is the remaining releaseable passive compensation strain of the alloy at the current temperature.

[0031] When converting the shape memory alloy compensation margin into the equivalent prestress compensation amount, the margin is multiplied by the equivalent elastic modulus of the Ti-Ni-Nb alloy, then multiplied by the cross-sectional area of ​​the temperature-changing compensation component within a single dovetail groove, and divided by the equivalent stress-bearing area of ​​the composite reinforcement layer at that cross-section. This yields the equivalent prestress compensation amount expressed in pressure units. This conversion process transforms the alloy's strain compensation capability into a value with the same dimensions as the pressure time series, allowing the two to be directly used in addition and subtraction calculations. The safety reserve is set at 2% of the prestress design threshold. This percentage is based on the fact that the combined influence of sensor measurement error and current control error is approximately between 1% and 2%. Setting it to 2% ensures that the measured value of the pressure time series after prestress compensation is consistently higher than the upper limit of the prestress design, preventing verification failure due to measurement errors. The target amount of pre-stress compensation is obtained by subtracting the equivalent pre-stress compensation amount from the sum of the pre-stress gap and the safety reserve. This value is directly used as the calculation input of the target drive current of the electromagnetic actuator in step S3, which quantifies the pre-stress increase that the electromagnetic actuator needs to independently bear in this single pre-stress compensation.

[0032] In one specific embodiment, step S3 includes: The required tension increment is calculated based on the pre-stored compensation target amount. The target driving current is obtained by performing a square root operation on the tension increment based on the coil structure coefficient of the electromagnetic actuator. The target driving current is applied to the electromagnetic actuator in a linear ramp manner within 120 seconds. After the ramp is completed, the pressure timing is verified by the pressure sensor. When the current value of the pressure timing is not less than the upper limit of the prestress design, the single pre-storage compensation is confirmed to be completed. The input current of the electromagnetic actuator is reduced to 0.3 times the target drive current as the holding current, and the system is switched to sleep mode. The Ti-Ni-Nb shape memory alloy temperature change compensation component passively accepts the slight fluctuations in the pressure timing within the range of ±3.2MPa of the prestress design threshold.

[0033] Specifically, the pre-stored compensation target is expressed in pressure units. Multiplying this by the equivalent stress area of ​​the composite reinforcement layer and dividing by the number of dovetail-shaped axial anchoring grooves yields the required tension increment for a single electromagnetic actuator. The excitation magnetic force of the electromagnetic actuator is proportional to the square of the input current. The coil structure coefficient is a proportionality constant of this relationship, determined by the number of turns of the actuator coil, the permeability of the iron core, and the geometric parameters of the magnetic circuit during factory calibration. The square root of the tension increment divided by the coil structure coefficient, i.e., the square root of the tension increment, yields the target driving current. The linear ramp-up method refers to uniformly increasing the input current from the current holding current value to the target driving current value at a constant rate. The ramp-up duration is set to 120 seconds. This duration is based on the fact that sudden current changes can cause impact loads on the composite reinforcement layer. The 120-second ramp-up process allows the tension increment to be applied slowly, avoiding instantaneous stress concentration on the FRP fiber bundles. After the ramp is completed, the pressure sensor reads the current value of the pressure timing and compares it with the upper limit of the prestressing design. If the current value is not less than the upper limit of the prestressing design, the pre-storage compensation is confirmed to be completed. Otherwise, the current current is maintained and the verification continues until the conditions are met.

[0034] After the single pre-charge compensation is confirmed, the electromagnetic actuator input current is reduced to 0.3 times the target drive current as the holding current. The 0.3 times setting is based on the fact that the magnetic force generated by this current value is sufficient to maintain the basic magnetic flux in the actuator's magnetic circuit, preventing the complete disappearance of the magnetic field from causing a sudden drop in the prestress of the composite reinforcement layer, while simultaneously reducing the actuator power consumption to the minimum level. The sleep mode refers to the working state in which the electromagnetic actuator maintains a constant holding current and does not respond to any pressure timing fluctuation signals. In this state, the actuator does not perform any active adjustment actions. The micro-fluctuation range of ±3.2MPa is determined by converting the maximum reversible phase deformation variable of the Ti-Ni-Nb shape memory alloy in the full temperature range of -30 degrees Celsius to 70 degrees Celsius into equivalent prestress. Within this range, the pressure timing fluctuation is completely compensated by the passive phase deformation of the alloy caused by temperature changes, without the need for electromagnetic actuator intervention. This clearly separates the single large pre-charge compensation of the actuator from the continuous passive temperature change compensation of the alloy in the time dimension.

[0035] In one specific embodiment, step S4 includes: Based on the difference between the measured prestress values ​​in the pressure time sequence before and after this single pre-storage compensation, the prestress increase range of this compensation is obtained. According to the prestress increase range, the equivalent stress area of ​​the composite reinforcement layer, the number of dovetail axial anchoring grooves, and the number of welds and the equivalent shear length of the welds on a single load-bearing steel plate, the shear stress at the welding interface is converted to obtain the interface shear stress increment. The interface shear stress increment is added to the historical interface shear stress increment accumulation. Based on the Palmgren-Miner linear damage accumulation criterion, the ratio of the historical interface shear stress increment accumulation to the fatigue shear strength of the FRP-metal welded interface is calculated to obtain the interface fatigue damage degree. The trigger threshold for the next cycle is adjusted in intervals based on the degree of interface fatigue damage. When the degree of interface fatigue damage is not greater than 0.6, the trigger threshold is kept at 3600s; when the degree of interface fatigue damage is greater than 0.6 but not greater than 0.8, the trigger threshold is adjusted to 5400s; when the degree of interface fatigue damage is greater than 0.8, the trigger threshold is adjusted to 1800s and an interface damage warning signal is output simultaneously.

[0036] Specifically, the increase in prestress after this single pre-storage compensation is obtained by subtracting the current pressure sequence value before compensation from the current pressure sequence value after the current compensation. This increase is then multiplied by the equivalent stress area of ​​the composite reinforcement layer to obtain the total tensile force increment of the composite reinforcement layer. The total tensile force increment is divided by the number of dovetail-shaped axial anchoring grooves to obtain the tensile force component borne by a single load-bearing steel plate. This tensile force component is then divided by the product of the number of weld points on a single load-bearing steel plate and the equivalent shear length of the weld points to obtain the interface shear stress increment at a single weld point. This value reflects the local shear stress amplitude injected into the FRP-metal weld interface during this compensation action. The equivalent shear length of the weld point is taken as the weld point spacing value, which is 50mm in this example. This is based on the fact that the interface shear force between adjacent weld points is jointly borne by the FRP fiber bundle and the steel plate within this length, and using the weld point spacing as the equivalent shear length matches the measured shear force distribution in the engineering.

[0037] The historical cumulative increase in interfacial shear stress is the arithmetic sum of the interfacial shear stress increments generated by each compensation since the reinforcement system was put into use. The Palmgren-Miner linear damage accumulation criterion stipulates that the fatigue damage degree of a structure under cyclic stress is equal to the sum of the damage caused by each stress cycle. The damage for a single cycle is calculated by dividing the stress increment by the interfacial fatigue shear strength. The fatigue shear strength of the FRP-metal welded interface is taken as 85 MPa, a value determined by the interfacial fatigue strength material calibration test of the braided composite reinforcement layer. The interfacial fatigue damage degree is the dimensionless ratio obtained by dividing the historical cumulative increase in interfacial shear stress by the fatigue shear strength of the FRP-metal welded interface, ranging from 0 to 1. Values ​​close to 1 indicate a sharp increase in the risk of interfacial fatigue failure. The interval boundary values ​​of 0.6 and 0.8 are set based on the following: in the Palmgren-Miner criterion, when the damage degree is below 0.6, the interface is in the safe zone of linear cumulative damage; when the damage degree is between 0.6 and 0.8, the damage accumulation rate begins to accelerate, entering the warning zone; and when the damage degree exceeds 0.8, the probability of interfacial failure increases significantly, entering the high-risk zone. The trigger threshold is adjusted to 5400s in the early warning zone, which delays the triggering of the next compensation and reduces the single compensation amplitude accordingly, thus reducing the shear stress increment of each injection into the interface. In the high-risk zone, it is adjusted to 1800s, replacing large single compensation with a higher trigger frequency and a smaller single compensation amplitude, keeping the shear stress increment of each interface at a lower level, and simultaneously outputting an interface damage early warning signal to notify maintenance personnel to arrange inspection.

[0038] The above describes the intelligent reinforcement method for reinforced concrete columns based on temperature change and creep compensation in the embodiments of this application. The following describes the intelligent reinforcement system for reinforced concrete columns based on temperature change and creep compensation in the embodiments of this application. One embodiment of the intelligent reinforcement system for reinforced concrete columns based on temperature change and creep compensation in the embodiments of this application includes: The acquisition module is used to acquire interlayer displacement time series and pressure time series by multi-source sensing units to obtain creep monitoring dataset; The fitting module is used to obtain the deformation acceleration sequence by fitting the interlayer displacement time series in the creep monitoring dataset through a sliding window least squares. When the difference between the linear extrapolation zero crossover time of the deformation acceleration sequence and the current time is not greater than the trigger threshold and the fitting confidence meets the preset conditions, the pre-stored compensation target amount is determined by the difference between the pressure time series and the upper limit of the prestress design and the shape memory alloy compensation margin. The switching module is used to drive the electromagnetic actuator to perform a single pre-stored compensation according to the pre-stored compensation target amount and then switch to the sleep mode, with the Ti-Ni-Nb shape memory alloy temperature change compensation component bearing the slight fluctuations in the pressure timing. The triggering module is used to accumulate the interface shear stress increment generated by this compensation to the interface fatigue damage degree, and to correct the triggering threshold for the next cycle based on the interface fatigue damage degree.

[0039] This invention also provides an intelligent reinforcement device for reinforced concrete columns based on temperature change and creep compensation. This device can be a server. The device includes a processor, memory, display screen, input device, network interface, and database connected via a system bus. The processor, designed as a computer, provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The database stores the data corresponding to this embodiment. The network interface communicates with external terminals via a network connection. The computer program, when executed by the processor, implements the above-described method.

[0040] The present invention also provides a computer-readable storage medium, which can be a non-volatile computer-readable storage medium or a volatile computer-readable storage medium, wherein the computer-readable storage medium stores instructions that, when the instructions are executed on a computer, cause the computer to perform the steps of the intelligent reinforcement method for reinforced concrete columns based on temperature change and creep compensation.

[0041] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0042] 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 smart reinforcement device for reinforced concrete columns based on temperature and creep compensation (which can 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 various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0043] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A smart reinforcement method for reinforced concrete columns based on temperature change and creep compensation, characterized in that, The method includes: Step S1: The interlayer displacement time series and pressure time series are collected by the multi-source sensing unit to obtain the creep monitoring dataset; Step S2: The interlayer displacement time series in the creep monitoring dataset is fitted using a sliding window least squares method to obtain the deformation acceleration sequence. When the difference between the linear extrapolation zero-crossing time of the deformation acceleration sequence and the current time is not greater than the trigger threshold and the fitting confidence meets the preset conditions, the pre-stored compensation target amount is determined based on the difference between the pressure time series and the upper bound of the prestress design and the shape memory alloy compensation margin. Specifically, the most recent 60 calculated values ​​in the deformation acceleration sequence are taken, and a linear regression fit is performed on the deformation acceleration sequence and the time series to obtain the regression slope and regression intercept. The regression slope and regression intercept are substituted into the zero-value equation to obtain the linear extrapolation zero-crossing time of the deformation acceleration sequence. The linear extrapolation zero-crossing time is then... The difference between the crossover moment and the current moment is used to obtain the predicted remaining time. When the predicted remaining time is not greater than the trigger threshold and the regression fitting determination coefficient is not less than 0.85, the pre-storage compensation preparation signal is triggered. Based on the difference between the current prestress value in the pressure time series and the upper limit of the prestress design, the prestress gap is obtained. Using the relative position of the current temperature within the phase transformation temperature range of the Ti-Ni-Nb shape memory alloy, the maximum bidirectional memory strain of the shape memory alloy is proportionally reduced to obtain the shape memory alloy compensation margin, and the shape memory alloy compensation margin is converted into an equivalent prestress compensation amount. The prestress gap is added to the safety reserve amount and then subtracted from the equivalent prestress compensation amount to obtain the pre-storage compensation target amount. Step S3: Drive the electromagnetic actuator to perform a single pre-stored compensation according to the pre-stored compensation target amount, and then switch to sleep mode. The Ti-Ni-Nb shape memory alloy temperature change compensation component will bear the slight fluctuation of the pressure timing. Step S4: The incremental interface shear stress generated by this compensation is added to the interface fatigue damage degree, and the trigger threshold for the next cycle is corrected based on the interface fatigue damage degree.

2. The intelligent reinforcement method for reinforced concrete columns based on temperature change and creep compensation according to claim 1, characterized in that, Step S1 includes: With a fixed sampling interval of 50ms, the pressure sensor continuously reads the contact pressure between the composite reinforcement layer and the electromagnetic actuator to obtain the pressure sampling sequence; Using the 50ms as a fixed sampling interval, the displacement sensor continuously reads the interlayer deformation at the interface between the composite reinforcement layer and the load-bearing steel plate to obtain a displacement sampling sequence; Using timestamps as indexes, the pressure sampling sequence and the displacement sampling sequence are time-aligned and concatenated to obtain a creep monitoring dataset containing interlayer displacement time series and pressure time series.

3. The intelligent reinforcement method for reinforced concrete columns based on temperature change and creep compensation according to claim 2, characterized in that, In step S2, the interlayer displacement time series in the creep monitoring dataset is fitted using a sliding window least squares method to obtain the deformation acceleration sequence, including: Using 11 consecutive sampling points as a sliding window, the inter-layer displacement time series is subjected to least squares linear fitting, and the slope obtained by fitting is used as the deformation rate value at the center time of the corresponding window to obtain the deformation rate sequence. Using the deformation rate sequence as input, least squares linear fitting is performed again with the same window length. The slope obtained from the fitting is used as the deformation acceleration value at the center of the corresponding window to obtain the deformation acceleration sequence. The deformation acceleration sequence is refreshed every 50 new data points collected and stored in a circular buffer.

4. The intelligent reinforcement method for reinforced concrete columns based on temperature change and creep compensation according to claim 1, characterized in that, Step S3 includes: The required tension increment is calculated based on the pre-stored compensation target amount, and the target driving current is obtained by performing a square root operation on the tension increment based on the coil structure coefficient of the electromagnetic actuator. The target driving current is applied to the electromagnetic actuator in a linear ramp manner within 120 seconds. After the ramp is completed, the pressure timing is verified by the pressure sensor. When the current value of the pressure timing is not less than the upper limit of the prestress design, the single pre-storage compensation is confirmed to be completed. The input current of the electromagnetic actuator is reduced to 0.3 times the target driving current as the holding current, and the system is switched to sleep mode. The Ti-Ni-Nb shape memory alloy temperature change compensation component passively absorbs the slight fluctuations in the pressure timing within the range of ±3.2MPa of the prestress design threshold.

5. The intelligent reinforcement method for reinforced concrete columns based on temperature change and creep compensation according to claim 1, characterized in that, Step S4 includes: Based on the difference between the measured values ​​of prestress in the pressure time sequence before and after this single pre-storage compensation, the prestress increase range of this compensation is obtained. According to the prestress increase range, the equivalent stress area of ​​the composite reinforcement layer, the number of dovetail axial anchoring grooves, and the number of welds and the equivalent shear length of the welds on a single load-bearing steel plate, the shear stress at the welding interface is converted to obtain the interface shear stress increment. The interface shear stress increment is added to the historical interface shear stress increment accumulation. Based on the Palmgren-Miner linear damage accumulation criterion, the ratio of the historical interface shear stress increment accumulation to the fatigue shear strength of the FRP-metal welded interface is calculated to obtain the interface fatigue damage degree. The trigger threshold for the next cycle is adjusted in intervals based on the interface fatigue damage degree. When the interface fatigue damage degree is not greater than 0.6, the trigger threshold is maintained at 3600s; when the interface fatigue damage degree is greater than 0.6 but not greater than 0.8, the trigger threshold is adjusted to 5400s; when the interface fatigue damage degree is greater than 0.8, the trigger threshold is adjusted to 1800s and an interface damage warning signal is output simultaneously.

6. A smart reinforcement system for reinforced concrete columns based on temperature change and creep compensation, characterized in that, For implementing the intelligent reinforcement method for reinforced concrete columns based on temperature change and creep compensation as described in any one of claims 1-5, the intelligent reinforcement system for reinforced concrete columns based on temperature change and creep compensation comprises: The acquisition module is used to acquire interlayer displacement time series and pressure time series by multi-source sensing units to obtain creep monitoring dataset; The fitting module is used to obtain a deformation acceleration sequence by fitting the interlayer displacement time series in the creep monitoring dataset using a sliding window least squares method. When the difference between the linear extrapolation zero-crossing time of the deformation acceleration sequence and the current time is not greater than a trigger threshold and the fitting confidence meets a preset condition, the pre-stored compensation target amount is determined based on the difference between the pressure time series and the upper bound of the prestress design and the shape memory alloy compensation margin. Specifically, the most recent 60 calculated values ​​in the deformation acceleration sequence are taken, and a linear regression fitting is performed on the deformation acceleration sequence and the time series to obtain the regression slope and regression intercept. The regression slope and regression intercept are substituted into the zero-value equation to obtain the linear extrapolation zero-crossing time of the deformation acceleration sequence. The difference between the crossover moment and the current moment is used to obtain the predicted remaining time. When the predicted remaining time is not greater than the trigger threshold and the regression fitting determination coefficient is not less than 0.85, the pre-storage compensation preparation signal is triggered. Based on the difference between the current prestress value in the pressure time series and the upper limit of the prestress design, the prestress gap is obtained. Using the relative position of the current temperature within the phase transformation temperature range of the Ti-Ni-Nb shape memory alloy, the maximum bidirectional memory strain of the shape memory alloy is proportionally reduced to obtain the shape memory alloy compensation margin, and the shape memory alloy compensation margin is converted into an equivalent prestress compensation amount. The prestress gap is added to the safety reserve amount and then subtracted from the equivalent prestress compensation amount to obtain the pre-storage compensation target amount. The switching module is used to drive the electromagnetic actuator to perform a single pre-stored compensation according to the pre-stored compensation target amount and then switch to the sleep mode, with the Ti-Ni-Nb shape memory alloy temperature change compensation component bearing the slight fluctuations in the pressure timing. The triggering module is used to accumulate the interface shear stress increment generated by this compensation to the interface fatigue damage degree, and to correct the triggering threshold for the next cycle based on the interface fatigue damage degree.

7. An intelligent reinforcement device for reinforced concrete columns based on temperature change and creep compensation, characterized in that, The method includes a memory and a processor, wherein the memory stores a computer program that can run on the processor, and the processor executes the computer program to implement the intelligent reinforcement method for reinforced concrete columns based on temperature change and creep compensation as described in any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is run by the processor, it causes the processor to execute the intelligent reinforcement method for reinforced concrete columns based on temperature change and creep compensation as described in any one of claims 1 to 5.

Images