Bridge dynamic performance rapid evaluation method based on dynamic displacement multi-parameter analysis

Abstract

The invention discloses a bridge dynamic performance rapid evaluation method based on dynamic displacement multi-parameter analysis. The method comprises the core steps that S1, a bridge theoretical fundamental frequency f theory and a theoretical impact coefficient mu theory are calculated, and dynamic load efficiency parameters are calibrated; s2, when the bridge is in a good state, the worst vehicle speed Vc, the maximum impact coefficient initial value mumax initial, the fundamental frequency initial value f initial, the first-order modal damping ratio initial value D initial and the quasi-static deformation reference value Ss are measured through a special loading vehicle; s3, collecting and processing daily patrol dynamic displacement data, and rapidly extracting and analyzing an actual measurement fundamental frequency f actual measurement, an actual measurement impact coefficient mu max actual measurement and an actual measurement damping ratio D actual measurement; and S4, comprehensively evaluating the dynamic performance of the bridge by analyzing the change conditions of the f actual measurement, the mumax actual measurement and the D actual measurement. According to the method, standardized rapid testing is achieved, single-time inspection only needs several minutes, traffic interruption is not needed, the rigidity, impact resistance and energy dissipation characteristics of the bridge structure are efficiently evaluated by means of the multiple objectively-quantified power parameters (the fundamental frequency, the impact coefficient and the damping ratio), and the scientificity and efficiency of daily inspection are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of bridge inspection technology, specifically relating to a rapid evaluation method for bridge dynamic performance based on multi-parameter dynamic displacement analysis. Background Technology

[0002] With the surge in traffic volume and the increasing aging of bridges, traditional bridge inspection methods are no longer sufficient to meet modern maintenance needs. Currently, routine bridge inspections mainly rely on manual visual observation or static parameter measurements (such as crack width and support displacement), which have the following limitations:

[0003] Highly subjective: Visual inspection is easily influenced by the experience of the inspectors, making it difficult to fully assess structural performance degradation;

[0004] Significant limitations: Static parameters cannot reflect the true response of a bridge under dynamic loads (such as impact effects);

[0005] In addition, existing methods for detecting natural vibration characteristics (such as modal analysis) have long testing times, making them difficult to integrate into routine inspection processes. Summary of the Invention

[0006] To address the problems in existing technologies, such as the inability of traditional visual inspections to quantify the degree of degradation of bridge dynamic performance, and the complexity, high cost, and difficulty in adapting dynamic testing methods to routine inspection scenarios, this invention provides a rapid assessment method for bridge dynamic performance based on multi-parameter dynamic displacement analysis. This solves the problem of limited technical means in routine bridge inspections, which makes it difficult to evaluate the structural dynamic performance.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for rapid evaluation of bridge dynamic performance based on multi-parameter dynamic displacement analysis, comprising the following steps:

[0008] S1, Bridge theoretical fundamental frequency f 理论 Theoretical impact coefficient μ 理论 Calculation of dynamic load efficiency calibration parameters;

[0009] S2. When the bridge is in good condition, determine the most unfavorable vehicle speed V. c Initial value of maximum impact coefficient μ max初始 Initial value of fundamental frequency f 初始 The initial value of the first-order modal damping ratio D 初始 and quasi-static deformation reference value S s ;

[0010] S3. Daily inspection and dynamic displacement data acquisition and processing, measured fundamental frequency f 实测 Measured impact coefficient μ max实测 Measured damping ratio D 实测 Rapid extraction and analysis;

[0011] S4. Comprehensive evaluation of the dynamic performance of bridge structures.

[0012] Further, step S1 includes the following sub-steps:

[0013] S11. Calculation of Theoretical Fundamental Frequency: Based on the bridge's as-built data and on-site measured data, a finite element model is established to calculate the bridge's theoretical fundamental frequency f. 理论 The theoretical impact coefficient μ is calculated according to the method provided in the current "General Specifications for Highway Bridge and Culvert Design". 理论 This serves as the minimum limit for subsequent measured fundamental frequency and measured impulse coefficient;

[0014] S12: Select one or more dedicated loading vehicles based on the actual situation, and determine the weight W of the loading vehicle through calculation. 车 To ensure that it meets the dynamic load test load efficiency η d Between 0.90 and 1.00.

[0015] Furthermore, the dynamic load test load efficiency η in step S12 d The calculation formula is:

[0016] η d =S d / S lmax

[0017] Among them, S d S represents the maximum internal force or deformation of the control section under dynamic load test. lmax This indicates the maximum internal force or deformation of the control section under the control load (ignoring impact).

[0018] Furthermore, step S2 includes the following sub-steps:

[0019] S21: Control the loading vehicle at different speeds V i The vehicle was driven across the bridge, and three tests were conducted for each speed condition. Dynamic deflection signals were collected using a linear displacement sensor or a bridge deflectometer. The impact coefficient μ of the loaded vehicle under different speed conditions was calculated and statistically analyzed using the obtained dynamic deflection time history curves. i Find the initial value of the maximum impact coefficient μ. max初始 and the corresponding worst speed V c ;

[0020] Furthermore, the impact coefficient μ in step S21 i The calculation formula is:

[0021] μ i =f dmaxi / f jmaxi -1

[0022] Among them, fdmaxi f represents the maximum dynamic deflection amplitude measured in the i-th test. jmaxi This represents the maximum static deflection value obtained by digital low-pass filtering in the i-th test.

[0023] S22: Control the loading vehicle at the most unfavorable speed V c The vehicle crossed the bridge at a constant speed and underwent three unobstructed driving tests. Speed ​​and dynamic deflection signals were collected using a speed sensor and a linear displacement sensor (or a bridge deflection meter) respectively.

[0024] S23: Integrate and filter the speed signal to generate the dynamic displacement time history curve S(t), and separate the vehicle-bridge coupling segment and the residual vibration segment signal;

[0025] S24: Perform a Fast Fourier Transform (FFT) on the signal of the dynamic displacement residual vibration segment to calculate the initial value of the fundamental frequency f. 初始 ;

[0026] S25: Perform free decay vibration analysis on the residual vibration segment signal of the dynamic displacement, extract vibration waveforms of at least 3 consecutive periods, and calculate the initial value D of the first-order modal damping ratio. 初始 ;

[0027] Furthermore, the damping ratio calculation formula in step S25 is as follows:

[0028] D 初始 =ln((A i -A ＇ i ) / (A i+n -A ＇ i+n )) / 2πn

[0029] Where n represents the number of waves involved in the calculation, A i A represents the first peak value involved in the calculation. ＇ i A represents the first trough value used in the calculation. i+n A represents the peak value of the wake wave involved in the calculation. ＇ i+n This indicates the trough value of the wake wave that is included in the calculation.

[0030] S26: Extract the maximum quasi-static deformation value S from the time history curves of dynamic deflection of the vehicle-axle coupling section obtained from three tests using a low-pass filter. si Take multiple S si The arithmetic mean of the bridge span structure under vehicle weight W is used as the basis for the bridge span structure. 车 and vehicle speed V c The quasi-static deformation reference value S s .

[0031] Furthermore, step S3 includes the following sub-steps:

[0032] S31: Install velocity sensors at mid-span or key sections of the bridge and set a reasonable sampling frequency;

[0033] S32: Select an appropriate time, without interference from other vehicles, to direct the loading vehicle to a speed of V. c The vehicle travels along a designated route, crossing bridges, and simultaneously collects vibration velocity signals.

[0034] S33: Integrate and filter the speed signal to generate the dynamic displacement time history curve S(t), and separate the vehicle-bridge coupling segment and the residual vibration segment signal;

[0035] S34: Perform a Fast Fourier Transform (FFT) on the residual frequency signal to extract the measured fundamental frequency f. 实测 ;

[0036] S35: Perform free decay vibration analysis on the residual vibration segment signal, extract vibration waveforms of at least 3 consecutive periods, and calculate the damping ratio D. 实测 ;

[0037] S36: Identify the absolute value of the maximum dynamic displacement within the vehicle-axle coupling section |S max | and calculate the measured impact coefficient μ max实测 ;

[0038] Furthermore, the impact coefficient μ in step S36 max实测 The calculation formula is:

[0039] μ max实测 =|S max | / S s

[0040] Furthermore, step S4 includes the following sub-steps:

[0041] S41: Calculate the measured fundamental frequency change rate Δf. If Δf > 5% or f 实测 <f 理论 The measurement was determined to be abnormal.

[0042] Furthermore, the formula for calculating the measured fundamental frequency change rate Δf in step S41 is as follows:

[0043] Δf=(f 初始 -f 实测 ) / f 初始 ×100%

[0044] S42: If the measured impact coefficient μ max实测 >μ max理论 The measurement was determined to be abnormal.

[0045] S43: Calculate the deviation rate ΔD between the measured value and the initial value of the first-order modal damping ratio. When ΔD > 30%, it is determined to be an abnormal measurement.

[0046] Furthermore, the formula for calculating the deviation rate ΔD between the measured damping ratio and the initial damping ratio in step S43 is as follows:

[0047] ΔD=|D 初始 -D 实测 | / D 初始 ×100%

[0048] S44: When the above-mentioned abnormal situation occurs, a retest should be conducted first. If the retest result is still abnormal, a further special inspection should be carried out to find out the cause.

[0049] The beneficial effects of this invention are as follows:

[0050] (1) This invention simplifies the traditionally time-consuming and complex power performance testing into a standardized and rapid testing process based on a specific loaded vehicle and a specific vehicle speed. The data collection and analysis time for a single daily inspection can be controlled within a few minutes, and there is no need to close traffic or interrupt bridge operation, which solves the core pain point that existing power testing methods are difficult to adapt to high-frequency and high-efficiency daily inspection scenarios.

[0051] (2) Unlike the subjective nature of visual inspections that rely on human experience, this invention precisely extracts and analyzes the measured fundamental frequency (f... 实测 ), measured impact coefficient (μ) max实测 ), measured damping ratio (D) 实测 Core dynamic parameters, such as structural stiffness, impact resistance, and energy dissipation characteristics, are used to quantitatively characterize the dynamic performance of bridges. These parameters directly reflect structural stiffness, impact resistance, and energy dissipation characteristics, providing an objective and measurable scientific basis for assessing the condition of bridges.

[0052] (3) Except for the use of linear displacement sensors or bridge deflectometers when collecting initial values ​​(which can be completed with the assistance of a third-party testing agency), during daily inspections, only one or more standardized loading vehicles, conventional speed sensors and supporting analysis software are needed to complete the collection and analysis of key data, which is easy to promote in grassroots maintenance units.

[0053] (4) Strict regulations were implemented to use calibrated dedicated loading vehicles, pass through at the most unfavorable speed at a constant speed, and collect data at fixed locations, ensuring a high degree of comparability of data obtained from testing at different times and by different personnel. This is the key foundation for achieving long-term effective condition monitoring and performance trend analysis. Attached Figure Description

[0054] Figure 1The flowchart shows a method for rapid evaluation of bridge dynamic performance based on multi-parameter dynamic displacement analysis.

[0055] Figure 2 This is a schematic diagram of the impact coefficient versus vehicle speed relationship curve;

[0056] Figure 3 A schematic diagram of the spectrum obtained by performing a Fast Fourier Transform (FFT) on the signal of the residual vibration segment of the dynamic displacement.

[0057] Figure 4 A waveform diagram for free decay vibration analysis of the residual vibration segment signal of dynamic displacement. Detailed Implementation

[0058] The following will be combined with the appendix Figures 1-4 This invention will be described in detail, and the technical solutions in the embodiments of this invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0059] This invention provides a rapid evaluation method for bridge dynamic performance based on multi-parameter dynamic displacement analysis, belonging to the field of bridge inspection technology. This method aims to solve the problems that traditional visual inspection cannot quantify dynamic performance, and that existing dynamic testing methods are complex, time-consuming, and difficult to adapt to routine inspections. It includes the following steps:

[0060] S1. Theoretical Calculation Stage: Based on the bridge's as-built data and design parameters, calculate the bridge's theoretical fundamental frequency f; according to bridge design specifications, calculate the bridge's theoretical impact coefficient μ; select a calibration loading vehicle and determine its weight W vehicle to ensure it meets the dynamic load test load efficiency η. d Satisfies: 0.90≤η d ≤1.00, where η d =S d / S lmax S d S represents the maximum internal force or deformation of the control section under the action of the calibration loading vehicle. lmax The maximum internal force or deformation of the control section under the design load (ignoring impact);

[0061] S2. Initial Calibration Phase: When the bridge is in good condition, execute: Control the calibration loading vehicle at different speeds V i The impact coefficient μ at various vehicle speeds was calculated based on the dynamic deflection time history curve after multiple crossings of the bridge. i Determine the initial value of the maximum impact coefficient μ max初始 and the corresponding worst speed V c ; Control the calibrated loading vehicle at the most unfavorable vehicle speed V.c The vehicle travels at a constant speed across the bridge, collecting speed and dynamic deflection signals. The speed signal is integrated and filtered to generate a dynamic displacement time history curve S(t), separating the vehicle-bridge coupling segment from the residual vibration segment. Spectral analysis is performed on the residual vibration segment signal to calculate the initial value of the fundamental frequency f. 初始 Perform free decay vibration analysis on the residual vibration segment signal, extract the continuous vibration waveform, and calculate the initial value D of the first-order mode damping ratio. 初始 Extract the maximum quasi-static deformation value from the dynamic deflection time history curve of the vehicle-bridge coupling section, and calculate the quasi-static deformation reference value S. s ;

[0062] S3. Routine Inspection Phase: Speed ​​sensors are installed at key sections of the bridge, and the calibrated loading vehicle is controlled at the most unfavorable speed V. c The vehicle travels at a constant speed across the bridge, and vibration velocity signals are collected. The velocity signals are integrated and filtered to generate a dynamic displacement time history curve S(t), separating the signals from the vehicle-bridge coupling segment and the residual vibration segment. Spectral analysis is performed on the residual vibration segment signal to extract the measured fundamental frequency f. 实测 Perform free decay vibration analysis on the residual vibration segment signal and calculate the measured damping ratio D. 实测 Identify the absolute value of the maximum dynamic displacement |S| within the vehicle-axle coupling section. max |, combined with the quasi-static deformation reference value S s Calculate the measured impact coefficient μ max实测 , where μ max实测

[0063] =|S max | / S s ;

[0064] S4. Comprehensive evaluation stage of dynamic performance: Calculate the measured fundamental frequency change rate Δf = (f 初始 -f 实测 ) / f 初始 ×100%, if Δf≥5% or f 实测 Bridge Theoretical Fundamental Frequency f 理论 If the measured impact coefficient μ is abnormal, then it is determined to be abnormal; max实测 Bridge theoretical impact coefficient μ 理论 If so, it is determined to be abnormal; calculate the damping ratio deviation rate ΔD = |D 初始 -D 实测 | / D 初始 ×100%, if ΔD>30%, then it is considered abnormal; when an abnormality occurs, a retest or special inspection should be carried out.

[0065] The impact coefficient μ i The specific calculation is as follows: μ i =f dmaxi / f jmaxi -1, where f dmaxif is the maximum dynamic deflection amplitude measured in the i-th test. jmaxi This represents the maximum static deflection value extracted from the same test signal after digital low-pass filtering.

[0066] The quasi-static deformation reference value S s The method for obtaining the value is as follows: the dynamic deflection time history curves of the vehicle-axle coupling section from the three tests in the initial calibration stage are used to extract the maximum quasi-static deformation value S through low-pass filtering. si Take the arithmetic mean as S s .

[0067] The damping ratio is calculated based on the peak and trough values ​​of n consecutive waves in a free decaying waveform, according to the formula: D = ln((A i -A' i ) / (A i+n -A' i+n )) / (2πn) where A i A' i These are the peak and trough values ​​of the first wave, respectively. i+n A' i+n These represent the peak and trough values ​​of the wake wave, respectively.

[0068] The spectrum analysis employs Fast Fourier Transform to extract the fundamental frequency.

[0069] The calibration loading vehicle has a weight of W. 车 A fixed and known dedicated vehicle is used, and the same vehicle or a vehicle of the same specification is used in both the routine inspection phase and the initial calibration phase.

[0070] The speed sensor is positioned at the mid-span of the bridge or other critical sections.

[0071] The abnormal judgment thresholds for each parameter are Δf>5%, f 实测 <f 理论 μ max实测 >μ 理论 ΔD>30% is used to trigger an early warning signal for abnormal dynamic characteristics of bridge structures.

[0072] Example

[0073] like Figure 1 As shown, this invention provides a rapid evaluation method for bridge dynamic performance based on multi-parameter dynamic displacement analysis, comprising the following steps:

[0074] S1, Bridge theoretical fundamental frequency f 理论 Theoretical impact coefficient μ 理论 Calculation of dynamic load efficiency calibration parameters;

[0075] S2. When the bridge is in good condition, determine the most unfavorable vehicle speed V. c Initial value of maximum impact coefficient μmax初始 Initial value of fundamental frequency f 初始 The initial value of the first-order modal damping ratio D 初始 and quasi-static deformation reference value S s ;

[0076] S3. Daily inspection and dynamic displacement data acquisition and processing, measured fundamental frequency f 实测 Measured impact coefficient μ max实测 Measured damping ratio D 实测 Rapid extraction and analysis;

[0077] S4. Comprehensive evaluation of the dynamic performance of bridge structures.

[0078] Further, step S1 includes the following sub-steps:

[0079] S11. Calculation of Theoretical Fundamental Frequency: Based on the bridge's as-built data and on-site measured data, a finite element model of the bridge is established using Midas Civil software to calculate the bridge's theoretical fundamental frequency f. 理论 The theoretical impact coefficient μ is calculated according to the method provided in the current "General Specifications for Highway Bridge and Culvert Design". 理论 This serves as the minimum limit for subsequent measured fundamental frequency and measured impulse coefficient;

[0080] S12: Select one or more dedicated loading vehicles based on the actual situation, and determine the weight W of the loading vehicle through calculation. 车 To ensure that it meets the dynamic load test load efficiency η d Between 0.90 and 1.00.

[0081] Furthermore, the dynamic load test load efficiency η in step S12 d The calculation formula is:

[0082] η d =S d / S lmax

[0083] Among them, S d S represents the maximum internal force or deformation of the control section under dynamic load test. lmax This indicates the maximum internal force or deformation of the control section under the control load (ignoring impact).

[0084] Furthermore, step S2 includes the following sub-steps:

[0085] S21: Control the loading vehicle to travel across the bridge at speeds of 5, 10, 20, 30, 40, 50, 60, 70, and 80 km / h respectively. Perform three tests for each speed condition. Use a linear displacement sensor or a bridge deflectometer to collect dynamic deflection signals. Calculate and statistically analyze the impact coefficient μ of the loading vehicle under different speed conditions using the obtained dynamic deflection time history curves.i Plot the impact coefficient-vehicle speed relationship curve as follows: Figure 2 Find the initial value of the maximum impact coefficient μ. max初始 =0.215 and the corresponding most unfavorable vehicle speed V c =60km / h;

[0086] Furthermore, the impact coefficient μ in step S21 i The calculation formula is:

[0087] μ i =f dmaxi / f jmaxi -1

[0088] Among them, f dmaxi f represents the maximum dynamic deflection amplitude measured in the i-th test. jmaxi This represents the maximum static deflection value obtained by digital low-pass filtering in the i-th test.

[0089] S22: Control the loading vehicle at the most unfavorable speed V c = Cross the bridge at a constant speed of 60km / h and conduct three barrier-free driving tests. Speed ​​and dynamic deflection signals are collected using a speed sensor and a linear displacement sensor (or a bridge deflection meter).

[0090] S23: Integrate and filter the speed signal to generate the dynamic displacement time history curve S(t), and separate the vehicle-bridge coupling segment and the residual vibration segment signal;

[0091] S24: Perform a Fast Fourier Transform (FFT) on the signal of the dynamic displacement residual vibration segment to generate the spectrum curve as shown below. Figure 3 Extract the initial value f of the fundamental frequency 初始 ;

[0092] S25: Perform free decay vibration analysis on the residual vibration segment signal of the dynamic displacement, and extract vibration waveforms of at least 3 consecutive periods, such as... Figure 4 Calculate the initial value D of the first-order modal damping ratio. 初始 ;

[0093] Furthermore, the damping ratio calculation formula in step S25 is as follows:

[0094] D 初始 =ln((A i -A ＇ i ) / (A i+n -A ＇ i+n )) / 2πn

[0095] Where n represents the number of waves involved in the calculation, A i A represents the first peak value involved in the calculation.＇ i A represents the first trough value used in the calculation. i+n A represents the peak value of the wake wave involved in the calculation. ＇ i+n This indicates the trough value of the wake wave that is included in the calculation.

[0096] S26: Extract the maximum quasi-static deformation value S from the time history curves of dynamic deflection of the vehicle-axle coupling section obtained from three tests using a low-pass filter. si Take multiple S si The arithmetic mean of the bridge span structure under vehicle weight W is used as the basis for the bridge span structure. 车 and vehicle speed V c The quasi-static deformation reference value S s .

[0097] Furthermore, step S3 includes the following sub-steps:

[0098] S31: Install velocity sensors at mid-span or key sections of the bridge and set a reasonable sampling frequency;

[0099] S32: When there are fewer vehicles at night, direct the loading vehicle to drive at a speed of V. c The vehicle travels along a designated route across a bridge, ensuring it is not affected by other vehicles, and simultaneously collects vibration velocity signals.

[0100] S33: Integrate and filter the speed signal to generate the dynamic displacement time history curve S(t), and separate the vehicle-bridge coupling segment and the residual vibration segment signal;

[0101] S34: Perform a Fast Fourier Transform (FFT) on the residual frequency signal to extract the measured fundamental frequency f. 实测 ;

[0102] S35: Perform free decay vibration analysis on the residual vibration segment signal, extract vibration waveforms of at least 3 consecutive periods, and calculate the damping ratio D. 实测 ;

[0103] S36: Identify the absolute value of the maximum dynamic displacement within the vehicle-axle coupling section |S max | and calculate the measured impact coefficient μ max实测 ;

[0104] Furthermore, the impact coefficient μ in step S36 max实测 The calculation formula is:

[0105] μ max实测 =|S max | / S s

[0106] Furthermore, step S4 includes the following sub-steps:

[0107] S41: Calculate the measured fundamental frequency change rate Δf. If Δf > 5% or f 实测 <f 理论 The measurement was determined to be abnormal.

[0108] Furthermore, the formula for calculating the measured fundamental frequency change rate Δf in step S51 is as follows:

[0109] Δf=(f 初始 -f 实测 ) / f 初始 ×100%

[0110] S42: If the measured impact coefficient μ max实测 >μ max理论 The measurement was determined to be abnormal.

[0111] S43: Calculate the deviation rate ΔD between the measured value and the initial value of the first-order modal damping ratio. When ΔD > 30%, it is determined to be an abnormal measurement.

[0112] Furthermore, the formula for calculating the deviation rate ΔD between the measured damping ratio and the initial damping ratio in step S43 is as follows:

[0113] ΔD=|D 初始 -D 实测 | / D 初始 ×100%

[0114] S44: When the above-mentioned abnormal situation occurs, a retest should be conducted first. If the retest result is still abnormal, a further special inspection should be carried out to find out the cause.

[0115] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A rapid evaluation method for the dynamic performance of bridges based on multi-parameter dynamic displacement analysis, characterized in that, Includes the following steps: S1, Bridge theoretical fundamental frequency f 理论 Theoretical impact coefficient μ 理论 Calculation of dynamic load efficiency calibration parameters; S2. When the bridge is in good condition, determine the most unfavorable vehicle speed V. c Initial value of maximum impact coefficient μ max初始 Initial value of fundamental frequency f 初始 The initial value of the first-order modal damping ratio D 初始 and quasi-static deformation reference value S s ; S3. Daily inspection and dynamic displacement data acquisition and processing, measured fundamental frequency f 实测 Measured impact coefficient μ max实测 Measured damping ratio D 实测 Rapid extraction and analysis; S4. Comprehensive evaluation of the dynamic performance of bridge structures.

2. The method for rapid evaluation of bridge dynamic performance based on multi-parameter dynamic displacement analysis according to claim 1, characterized in that, Step S1 includes the following sub-steps: S11. Calculation of Theoretical Fundamental Frequency: Based on the bridge's as-built data and on-site measured data, a finite element model is established to calculate the bridge's theoretical fundamental frequency f. 理论 Calculate the theoretical impact coefficient μ 理论 This serves as the minimum limit for subsequent measured fundamental frequency and measured impulse coefficient; S12: Select one or more dedicated loading vehicles based on the actual situation, and determine the weight W of the loading vehicle through calculation. 车 To ensure that it meets the dynamic load test load efficiency η d Between 0.90 and 1.

00.

3. The method for rapid evaluation of bridge dynamic performance based on multi-parameter dynamic displacement analysis according to claim 2, characterized in that, The dynamic load test load efficiency η in step S12 d The calculation formula is: or d =S d / S lmax Among them, S d S represents the maximum internal force or deformation of the control section under dynamic load test. lmax This indicates the maximum internal force or deformation of the control section under the control load (ignoring impact).

4. The method for rapid evaluation of bridge dynamic performance based on multi-parameter dynamic displacement analysis according to claim 1, characterized in that, Step S2 includes the following sub-steps: S21: Control the loading vehicle at different speeds V i The vehicle was driven across the bridge, and three tests were conducted for each speed condition. Dynamic deflection signals were collected using a linear displacement sensor or a bridge deflectometer. The impact coefficient μ of the loaded vehicle under different speed conditions was calculated and statistically analyzed using the obtained dynamic deflection time history curves. i Find the initial value of the maximum impact coefficient μ. max初始 and the corresponding worst speed V c ; The impact coefficient μ in step S21 i The calculation formula is: m i =f dmaxi / f jmaxi -1 Among them, f dmaxi f represents the maximum dynamic deflection amplitude measured in the i-th test. jmaxi This represents the maximum static deflection value obtained by digital low-pass filtering in the i-th test; S22: Control the loading vehicle at the most unfavorable speed V c The vehicle crossed the bridge at a constant speed and underwent three unobstructed driving tests. Speed ​​and dynamic deflection signals were collected using a speed sensor and a linear displacement sensor (or a bridge deflection meter) respectively. S23: Integrate and filter the speed signal to generate the dynamic displacement time history curve S(t), and separate the vehicle-bridge coupling segment and the residual vibration segment signal; S24: Perform a Fast Fourier Transform (FFT) on the signal of the dynamic displacement residual vibration segment to calculate the initial value of the fundamental frequency f. 初始 ; S25: Perform free decay vibration analysis on the residual vibration segment signal of the dynamic displacement, extract vibration waveforms of at least 3 consecutive periods, and calculate the initial value D of the first-order modal damping ratio. 初始 ; Furthermore, the damping ratio calculation formula in step S25 is as follows: D 初始 =ln((A i -A ＇ i ) / (A i+n -A ＇ i+n )) / 2πn Where n represents the number of waves involved in the calculation, A i A represents the first peak value involved in the calculation. ＇ i A represents the first trough value used in the calculation. i+n A represents the peak value of the wake wave involved in the calculation. ＇ i+n This indicates the value of the wake trough that was included in the calculation; S26: Extract the maximum quasi-static deformation value S from the time history curves of dynamic deflection of the vehicle-axle coupling section obtained from three tests using a low-pass filter. si Take multiple S si The arithmetic mean of the bridge span structure under vehicle weight W is used as the basis for the bridge span structure. 车 and vehicle speed V c The quasi-static deformation reference value S s .

5. The method for rapid evaluation of bridge dynamic performance based on multi-parameter dynamic displacement analysis according to claim 1, characterized in that, Step S3 includes the following sub-steps: S31: Install velocity sensors at mid-span or key sections of the bridge and set a reasonable sampling frequency; S32: Select an appropriate time, without interference from other vehicles, to direct the loading vehicle to a speed of V. c The vehicle travels along a designated route, crossing bridges, and simultaneously collects vibration velocity signals. S33: Integrate and filter the speed signal to generate the dynamic displacement time history curve S(t), and separate the vehicle-bridge coupling segment and the residual vibration segment signal; S34: Perform a Fast Fourier Transform (FFT) on the residual frequency signal to extract the measured fundamental frequency f. 实测 ; S35: Perform free decay vibration analysis on the residual vibration segment signal, extract vibration waveforms of at least 3 consecutive periods, and calculate the damping ratio D. 实测 ; S36: Identify the absolute value of the maximum dynamic displacement within the vehicle-axle coupling section |S max | and calculate the measured impact coefficient μ max实测 ; Furthermore, the impact coefficient μ in step S36 max实测 The calculation formula is: m max实测 =|S max | / S s 6. The method for rapid evaluation of bridge dynamic performance based on multi-parameter dynamic displacement analysis according to claim 1, characterized in that, Step S4 includes the following sub-steps: S41: Calculate the measured fundamental frequency change rate Δf. If Δf > 5% or f 实测 <f 理论 The measurement was determined to be abnormal. Furthermore, the formula for calculating the measured fundamental frequency change rate Δf in step S41 is as follows: Δf=(f 初始 -f 实测 ) / f 初始 ×100% S42: If the measured impact coefficient μ max实测 >μ max理论 The measurement was determined to be abnormal. S43: Calculate the deviation rate ΔD between the measured value and the initial value of the first-order mode damping ratio. When ΔD > 30%, it is judged as an abnormal measurement. Furthermore, the formula for calculating the deviation rate ΔD between the measured damping ratio and the initial damping ratio in step S43 is as follows: ΔD=|D 初始 -D 实测 | / D 初始 ×100% S44: When the above-mentioned abnormal situation occurs, a retest should be conducted first. If the retest result is still abnormal, a further special inspection should be carried out to find out the cause.

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