A method and system for monitoring and rapidly evaluating and analyzing lightweight of small and medium span highway bridges

Abstract

The application provides a small and medium span highway bridge lightweight monitoring and rapid evaluation analysis method and system, comprising: a bridge parameterization rapid input module, a vehicle load batch input module, a measuring point information arrangement module, a finite element calculation analysis module, a batch load working condition measuring point result automatic extraction module and a cloud highway bridge structure response monitoring module. It has the following advantages: 1. Without carrying out bridge site appearance quality collection, material performance test, dynamic characteristic test and other work, based on the standardization structure characteristics of small and medium span bridges, the dynamic deflection of the key cross section position measuring point is monitored, the safety passing coefficient of the bridge can be evaluated in real time, and the real-time evaluation result is realized; 2. In any traffic flow condition, the real-time dynamic checking coefficient of the bridge under different driving conditions of various types of overloaded vehicles can be accurately calculated, and timely safety warning is realized, a large amount of manpower, material resources and other expenditures required by load test are saved, and the cost is greatly reduced.

Description

Technical Field

[0001] This invention belongs to the technical field of bridge monitoring and bridge heavy vehicle traffic capacity assessment, specifically involving a lightweight monitoring and rapid assessment analysis method and system for small and medium span highway bridges. Background Technology

[0002] During long-term service, small- and medium-span bridges inevitably suffer structural damage and load capacity reduction due to the combined effects of environmental erosion, material aging, and the long-term, fatigue, and abrupt effects of loads. Therefore, under overloaded vehicle loads, bridges pose significant safety risks, necessitating a safety analysis and assessment of their traffic capacity. Existing technologies often employ bridge calculation methods such as on-site data collection (appearance quality, material properties, dynamic characteristics, etc.) and structural theoretical analysis to assess bridge load-bearing capacity, or use load testing methods and rapid loading methods with specific heavy vehicles to evaluate bridge traffic capacity. For rapid loading methods with specific heavy vehicles, patent number ZL 202310428067.4 discloses a method and system for assessing bridge load-bearing capacity based on dynamic strain under non-closed traffic conditions, and application number CN202211500132 discloses a method for assessing bridge load-bearing capacity based on monitoring of passing vehicle loads and dynamic deflection.

[0003] Traditional methods for assessing bridge traffic capacity have the following problems:

[0004] 1. Traditional bridge load-bearing capacity assessment cycles are long, generally 1-3 years, making it impossible to grasp the bridge's traffic capacity status in real time, resulting in insufficient effectiveness. At the same time, it is necessary to collect various parameters such as bridge appearance quality, material performance, and dynamic characteristics, which requires a lot of manpower and material resources, resulting in high costs.

[0005] 2. For different types of overweight vehicles, it is impossible to calculate the traffic capacity of overweight vehicles in real time and accurately. It is often necessary to use load test methods for evaluation and calculation, which has problems such as high cost and need to close traffic.

[0006] 3. The specific heavy vehicle rapid loading method often requires the selection of specific test vehicles and the selection of time periods with less traffic flow to carry out the test. It cannot use the actual vehicle load on the bridge deck for testing, and it has certain limitations due to the high requirements on the traffic flow on the bridge deck. At the same time, it cannot reflect the current heavy vehicle traffic capacity of the bridge in real time. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a method and system for lightweight monitoring and rapid evaluation analysis of small- and medium-span highway bridges, which can effectively solve the aforementioned problems.

[0008] The technical solution adopted in this invention is as follows:

[0009] This invention provides a method for lightweight monitoring and rapid evaluation analysis of small-to-medium span highway bridges, comprising the following steps:

[0010] Step S1: Select and deploy a vehicle weighing system and a vehicle position recognition system based on the characteristics of the bridge structure;

[0011] Step S2: Calibrate the vehicle weighing system and the vehicle position recognition system respectively to obtain the calibrated vehicle weighing system and the vehicle position recognition system;

[0012] Step S3: Select the test section and set up the corresponding test sections. Each measuring point; Deploy wireless torsion gauges; ;

[0013] Step S4: Establish the finite element model of the bridge;

[0014] Step S5, On-site data acquisition:

[0015] Step S5.1: Determine the sampling frequency; synchronously start the vehicle weighing system, the vehicle position recognition system, and each measuring point within the sampling time range. The wireless torsion gauges that have been deployed;

[0016] Step S5.2, at each sampling point within the acquisition time range The vehicle weighing system obtains the vehicle parameters of each overweight vehicle traveling on the bridge; the vehicle position recognition system obtains the vehicle position parameters of each overweight vehicle traveling on the bridge; each sampling point The vehicle parameters and vehicle position parameters of all overweight vehicles form a batch load condition acting on the bridge deck. ;

[0017] Step S5.3, at each sampling point within the acquisition time range The wireless torsion gauge is used to obtain the readings for each measuring point. under batch load conditions Measured dynamic deflection value at the measuring point under action ;

[0018] Step S6, for each sampling point The obtained batch load conditions The theoretical impact coefficient is obtained by inputting the data into the finite element model of the bridge and using the spatial finite element method. Based on the finite element model of the bridge, batch load cases were obtained respectively. Static displacement of measuring point under load and measuring points under design load static load displacement of measuring points ;

[0019] Step S7: Use formula (1) to measure the dynamic deflection value at the measuring point. After correction, the measured dynamic deflection value at the measuring point is obtained. :

[0020] (1)

[0021] Step S8: Using formulas (2) and (3), the verification coefficients of the first dynamic deflection at the measuring point are obtained respectively. and the second dynamic deflection verification coefficient at the measuring point :

[0022] (2)

[0023] (3)

[0024] Step S9, verify the first dynamic deflection coefficient at the measuring point. and the second dynamic deflection verification coefficient at the measuring point Determine whether the bridge meets the current batch load conditions. Traffic capacity.

[0025] Furthermore, the vehicle weighing system is used to identify the vehicle parameters of overweight vehicles traveling on the bridge deck, including axle load, wheelbase, and track width; the vehicle position identification system is used to measure the vehicle position parameters of overweight vehicles on the bridge deck in real time based on the bridge axle support baseline, including the bridge deck station number of the vehicle's front axle center, support distance, and direction of travel; the support distance is the distance between the vehicle center and the bridge deck centerline.

[0026] Furthermore, the vehicle weighing system and the vehicle position recognition system are calibrated respectively to obtain the calibrated vehicle weighing system and the vehicle position recognition system, specifically as follows:

[0027] Step S2.1: Select a calibration vehicle with a weight of not less than 35t and equipped with a vehicle position indicator;

[0028] Step S2.2: Measure and calibrate the vehicle's geometric parameters, including wheelbase and track width;

[0029] Step S2.3: Weigh the calibrated vehicle to accurately obtain the axle weight of each axle and the total axle weight.

[0030] Step S2.4, conduct testing using a calibrated vehicle:

[0031] During periods of low traffic, the calibration vehicle was idling through each lane of the bridge in sequence, ensuring no interference from other vehicles during the test. While the calibration vehicle was passing through, its vehicle position indicator collected the vehicle position parameters on the bridge surface in real time. Simultaneously, the vehicle position recognition system was activated to measure the vehicle position parameters of the calibration vehicle as it passed through the bridge surface in real time. While the calibration vehicle was passing through, the vehicle weighing system measured the vehicle parameters of the calibration vehicle.

[0032] Step S2.5, Vehicle weighing system calibration:

[0033] The vehicle parameters of the calibrated vehicle measured by the vehicle weighing system are compared with the vehicle parameters measured in steps S2.2 and S2.3, and the vehicle weighing system is calibrated based on the difference.

[0034] Step S2.6, Vehicle location recognition system calibration:

[0035] The vehicle position parameters measured in real time by the vehicle position recognition system are compared with those collected in real time by the vehicle position indicator, and the vehicle position recognition system is calibrated based on the difference.

[0036] Furthermore, the test section is selected and the corresponding test sections are arranged. There are 1 measuring point, specifically:

[0037] Based on the displacement influence line method, the section with the largest deformation of the main beam is selected as the test section;

[0038] A measuring point is set at the bottom of each beam directly below the test section. For beams with... Bridges with a single main girder, layout There are 10 measurement points.

[0039] Furthermore, the establishment of the bridge finite element model specifically involves:

[0040] Based on a general cross-section library of small and medium-span bridges, a parametric method is adopted, combined with cross-section mesh generation, hexahedral geometric stretching, and nodal displacement coordination algorithms, to build a rapid modeling assistant and establish a planar model of small and medium-span bridges and a corresponding three-dimensional solid space finite element model.

[0041] Furthermore, the method for determining the sampling frequency is as follows:

[0042] The sampling frequency of the bridge during the average daily peak traffic period was calculated. ;in, The speed of the loaded vehicle; This is the sampling step size;

[0043] Take the maximum value of the sampling frequency during the daily average peak period of the vehicle. , which serves as the determined sampling frequency.

[0044] Furthermore, based on the bridge finite element model, batch load cases were obtained. Static displacement of measuring point under load Also known as batch load case The theoretical dynamic deflection value of the measuring point under action is as follows:

[0045] Batch load conditions Input the finite element model of the bridge, convert the vehicle axle loads into nodal forces, and simultaneously apply them to the finite element model according to the positions of each vehicle. Based on the spatial finite element method, calculate the bridge deck under batch load conditions. Static displacement of measuring point under load .

[0046] Furthermore, based on the dynamic verification coefficient of the measuring points... and real-time dynamic verification coefficients of measuring points Determine whether the bridge meets the current batch load conditions. The following are the traffic capacities:

[0047] Step S9.1, for each measuring point , Each sampling point within the collection time range The second dynamic deflection verification coefficient was obtained for each measurement point, and the values ​​of each sampling point were taken. The maximum value of the second dynamic deflection verification coefficient at the measuring point is the value of the measuring point. Maximum dynamic deflection verification coefficient ;

[0048] Step S9.2, according to formula (4), for each sampling point within the collection time range Maximum dynamic deflection verification coefficient The average value is used to obtain the second dynamic deflection verification coefficient of the bridge. :

[0049] (4)

[0050] in: This refers to the number of sampling points within the data collection time range.

[0051] Step S9.3, if Determine if the bridge meets the traffic capacity under batch load conditions; if It can be determined that the bridge does not meet the traffic capacity under batch load conditions;

[0052] Step S9.4, verify the first dynamic deflection coefficient at each measuring point. Take the average value. If the average value is less than 1, it indicates that the bridge deck load is within the design bearing capacity of the bridge structure.

[0053] Furthermore, it also includes:

[0054] An automatic bridge safety early warning and report output module is established to display in real time the vehicle parameters and position parameters of heavy vehicles, the measured dynamic deflection values ​​collected at each measuring point, and the calculated first and second dynamic deflection verification coefficients. If either the first or second dynamic deflection verification coefficient is greater than 1, an early warning is issued. The automatic report output includes: bridge overview, monitoring and calculation basis, lightweight monitoring scheme layout, bridge theoretical calculation model, measured data and analysis, bridge passability results, traffic recommendations, and attachments.

[0055] The present invention also provides a system for implementing the aforementioned method for lightweight monitoring and rapid evaluation and analysis of small and medium span highway bridges, comprising: a bridge parameterization rapid input module, a vehicle load batch input module, a measuring point information layout module, a finite element calculation and analysis module, a batch load condition measuring point result automatic extraction module, and a cloud-based highway bridge structural response monitoring module.

[0056] The bridge parameterization rapid input module provides a bridge parameter input interface and interface, specifically used for: 1) establishing a database of various cross-sections of the bridge structure under different spans and bridge deck widths based on general library drawings; 2) constructing a parameter customization interface for span, material, bridge deck width, and cross-sectional form; 3) constructing a bridge structure parameter definition interface and establishing a bridge structure parameter data model; to meet the diverse needs of bridge structures, it supports the establishment and modification of the bridge structure parameter data model.

[0057] The vehicle load batch input module is used to acquire and input the position data of vehicles on the bridge deck at fixed steps in real time. Specifically, it is used to: 1) establish a customizable and visual interface for load parameters including axle load, wheelbase, track width, and speed; 2) establish a data transmission interface with the cloud-based vehicle recognition system module, supporting multi-format input.

[0058] The measuring point information arrangement module enables the arrangement of measuring points for the actual measured dynamic deflection and static displacement of the bridge on site, in order to test the response characteristics of the bridge under load. Specifically, it is used for: 1) establishing a customizable and visual interface for measuring point parameters; 2) establishing an intelligent recommended test section algorithm based on the principle of the most unfavorable section and using the influence line method; 3) establishing an automatic bridge measuring point arrangement algorithm based on the cross-sectional characteristics and the requirements for bridge spatial mechanical response testing, combined with the requirements for measuring point arrangement.

[0059] The finite element analysis module provides static and dynamic calculation and analysis functions for bridge structures, specifically for: 1) obtaining the design load effect value of the test section based on the influence line method using standard vehicle loads, and establishing the vehicle load case of the design load; 2) establishing the three-dimensional spatial node element relationship matrix, displacement compatibility equation, and node load value based on a dynamic link library for the bridge parameterized rapid input module and the vehicle load batch input module, and outputting a finite element analysis file that meets the calculation format requirements; 3) calculating the static response results of the bridge structure under multiple load cases based on the finite element calculation kernel; and 4) calculating the theoretical impact coefficient of the bridge structure based on a planar truss model. ;

[0060] The automatic extraction module for batch load condition measurement point results extracts the theoretical calculation results of each measurement point under each load condition in batches based on the finite element calculation and analysis results of the finite element calculation and analysis module. Specifically, it is used for: 1) establishing a bridge spatial three-dimensional coordinate information conversion algorithm based on the data from the measurement point information layout module; 2) locating the entity element where the measurement point is located based on the spatial position geometry algorithm; 3) establishing the displacement derivation relationship of the measurement point based on the nodal displacement results of the entity element and the distance weight relationship between the measurement point and the entity element; 4) establishing a data display interface for the measurement point results and a data visualization interface for each load condition.

[0061] The cloud-based highway bridge structure response monitoring module enables real-time acquisition of on-site vehicle data and measuring point data, real-time analysis of bridge dynamic verification coefficients, and bridge safety early warning functions. It mainly includes a vehicle weighing system, a vehicle position identification system, and a dynamic deflection monitoring system.

[0062] The lightweight monitoring and rapid evaluation analysis method and system for small and medium span highway bridges provided by this invention has the following advantages:

[0063] 1. There is no need to carry out on-site collection of bridge appearance quality, material performance testing, dynamic characteristic testing, etc. Based on the standardized structural characteristics of small and medium span bridges, the safety coefficient of the bridge can be evaluated in real time by only monitoring the dynamic deflection of the measuring points at key cross-sections, thus realizing the real-time evaluation results.

[0064] 2. Without the need to close traffic to conduct bridge load tests or conduct specific test vehicle flow-limited load tests, it can accurately calculate the real-time dynamic verification coefficient of bridges under different driving conditions for various types of overweight vehicles under any traffic flow conditions, and provide timely safety warnings. This reduces the impact of traffic closures or flow restrictions, saves a lot of manpower and material resources required for load tests, and greatly reduces costs. Attached Figure Description

[0065] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0066] Figure 1 A flowchart of the lightweight monitoring and rapid evaluation analysis method for small- and medium-span highway bridges provided by the present invention;

[0067] Figure 2 This is a diagram showing the layout of measuring points provided in an embodiment of the present invention.

[0068] Figure 3 The image shows the effect of the bridge finite element model provided in the embodiment of the present invention. Detailed Implementation

[0069] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the invention.

[0070] This invention targets a large number of small-to-medium span highway bridges, conducting real-time assessment and analysis of heavy vehicle traffic. By constructing an integrated data acquisition and calculation analysis software system, it calculates the stress, strain, and displacement distribution of the bridge when heavy vehicles pass. Combined with real-time data collected on-site, it calculates the dynamic verification coefficient of the bridge structure in real time. Based on the calculation results, it automatically calculates the safety factor of the bridge, effectively solving the problems of large workload, high cost, traffic closure, and insufficient effectiveness in existing bridge heavy vehicle traffic assessment methods.

[0071] Under conditions of heavy vehicle traffic, the main girder structure of a bridge exhibits a corresponding structural response. Dynamic deflection at key sections is one of the critical parameters. A real-time dynamic deflection verification coefficient based on measured data can reflect the heavy vehicle passage performance of the main girder. Therefore, this invention proposes a rapid evaluation method for the heavy vehicle passage performance of bridges under non-specific heavy vehicle traffic conditions, based on lightweight monitoring. (See reference...) Figure 1 The specific steps are as follows:

[0072] Step S1: Select and deploy a vehicle weighing system and a vehicle position recognition system based on the characteristics of the bridge structure;

[0073] The vehicle weighing system is used to identify the vehicle parameters of overweight vehicles traveling on the bridge deck, including axle load, wheelbase, and track width. The vehicle position recognition system is used to measure the vehicle position parameters of overweight vehicles on the bridge deck in real time based on the bridge abutment reference line, including the bridge deck station number of the vehicle's front axle center, the offset, and the direction of travel. The offset is the distance between the vehicle's center and the bridge deck centerline. The direction of travel is whether the vehicle is traveling towards the side with the larger or smaller station number.

[0074] Step S2: Calibrate the vehicle weighing system and the vehicle position recognition system respectively to obtain the calibrated vehicle weighing system and the vehicle position recognition system;

[0075] This step is specifically as follows:

[0076] Step S2.1: Select a suitable calibration vehicle with a weight not less than 35t and equipped with a vehicle position indicator with a position resolution not less than 0.01m. The vehicle position indicator includes, but is not limited to, global navigation satellite system, roller-type position indicator, laser-type position indicator, etc.

[0077] Step S2.2: Measure the geometric parameters of the calibrated vehicle, including wheelbase and track width; specifically, accurately measure the track width between the two wheels of a single axle and the wheelbase between adjacent axles, with a distance accuracy of not less than 0.1m.

[0078] Step S2.3: Weigh the calibrated vehicle to accurately obtain the axle load of each axle and the total axle load (WGV); the weighing accuracy should not be less than 0.01t.

[0079] Step S2.4, conduct testing using a calibrated vehicle:

[0080] During periods of low traffic, the calibration vehicle was idling through each lane of the bridge in sequence, ensuring no interference from other vehicles during the test. While the calibration vehicle was passing, its vehicle position indicator collected its position parameters on the bridge surface in real time. Simultaneously, the vehicle position recognition system was activated to measure the vehicle position parameters as it crossed the bridge surface. The vehicle weighing system also measured the vehicle parameters while the calibration vehicle was passing.

[0081] Step S2.5, Vehicle weighing system calibration:

[0082] The vehicle parameters of the calibrated vehicle measured by the vehicle weighing system are compared with the vehicle parameters determined in steps S2.2 and S2.3. The vehicle weighing system is calibrated based on the difference until the error should be less than 1%.

[0083] Step S2.6, Vehicle location recognition system calibration:

[0084] Compare the vehicle position parameters measured in real time by the vehicle position recognition system with the vehicle position parameters collected in real time by the vehicle position indicator, and calibrate the vehicle position recognition system based on the difference until the error should be less than 1%.

[0085] Step S3: Select the test section and set up the corresponding test sections. Each measuring point; Deploy wireless torsion gauges; ;

[0086] Specifically, based on the displacement influence line method, the section with the largest deformation of the main beam is selected as the test section;

[0087] A measuring point is set at the bottom of each beam directly below the test section. For beams with... Bridges with a single main girder, layout There are 10 measurement points.

[0088] Step S4: Establish the finite element model of the bridge;

[0089] Based on a general cross-section library of small and medium-span bridges, a rapid modeling assistant is constructed using parametric methods and algorithms such as cross-section mesh generation, hexahedral geometric stretching, and nodal displacement coordination. This assistant establishes planar models of small and medium-span bridges and corresponding three-dimensional solid space finite element models.

[0090] Step S5, On-site data acquisition:

[0091] Step S5.1: Determine the sampling frequency; synchronously start the vehicle weighing system, the vehicle position recognition system, and each measuring point within the sampling time range. The wireless torsion gauges that have been deployed;

[0092] The method for determining the sampling frequency is as follows:

[0093] The sampling frequency of the bridge during the average daily peak traffic period was calculated. ;in, The speed of the loaded vehicle; The sampling step size is typically 0.5m.

[0094] Take the maximum value of the sampling frequency during the daily average peak period of the vehicle. , which serves as the determined sampling frequency.

[0095] Step S5.2, at each sampling point within the acquisition time range The vehicle weighing system obtains vehicle parameters for each overweight vehicle (single axle load ≥ 8t) traveling on the bridge; the vehicle position recognition system obtains vehicle position parameters for each overweight vehicle traveling on the bridge; each sampling point... The vehicle parameters and vehicle position parameters of all overweight vehicles form a batch load condition acting on the bridge deck. ;

[0096] Specifically, real-time data collection of vehicle parameters for heavy vehicles traveling on the bridge includes: - Wheelbase, -Axle load, - Wheelbase, -Speed, here. Assign vehicle number, Assign axle numbers to vehicles; when there are multiple loaded vehicles, collect data simultaneously to establish a vehicle location set on the bridge deck. -Vehicle front axle marker, - The distance between the center of the vehicle's front axle and the center of the bridge deck.

[0097] Step S5.3, at each sampling point within the acquisition time range The wireless torsion gauge is used to obtain the readings for each measuring point. under batch load conditions Measured dynamic deflection value at the measuring point under action ;

[0098] Step S6, for each sampling point The obtained batch load conditions The theoretical impact coefficient is obtained by inputting the data into the finite element model of the bridge and using the spatial finite element method. Based on the finite element model of the bridge, batch load cases were obtained respectively. Static displacement of measuring point under load and measuring points under design load static load displacement of measuring points ;

[0099] Based on the finite element model of the bridge, batch load cases were obtained. Static displacement of measuring point under load Also known as batch load case The theoretical dynamic deflection value of the measuring point under action is as follows:

[0100] Batch load conditions Input the finite element model of the bridge, convert the vehicle axle loads into nodal forces, and simultaneously apply them to the finite element model according to the positions of each vehicle. Based on the spatial finite element method, calculate the bridge deck under batch load conditions. Static displacement of measuring point under load .

[0101] Step S7: Use formula (1) to measure the dynamic deflection value at the measuring point. After correction, the measured dynamic deflection value at the measuring point is obtained. :

[0102] (1)

[0103] Step S8: Using formulas (2) and (3), the verification coefficients of the first dynamic deflection at the measuring point are obtained respectively. and the second dynamic deflection verification coefficient at the measuring point :

[0104] (2)

[0105] (3)

[0106] Step S9, Bridge vehicle traffic capacity assessment: Based on the first dynamic deflection verification coefficient at the measuring point. and the second dynamic deflection verification coefficient at the measuring point Determine whether the bridge meets the current batch load conditions. Traffic capacity.

[0107] This step is specifically as follows:

[0108] Step S9.1, for each measuring point , Each sampling point within the collection time range The second dynamic deflection verification coefficient was obtained for each measurement point, and the values ​​of each sampling point were taken. The maximum value of the second dynamic deflection verification coefficient at the measuring point is the value of the measuring point. Maximum dynamic deflection verification coefficient ;

[0109] Step S9.2, according to formula (4), for each sampling point within the collection time range Maximum dynamic deflection verification coefficient The average value is used to obtain the second dynamic deflection verification coefficient of the bridge. :

[0110] (4)

[0111] in: This refers to the number of sampling points within the data collection time range.

[0112] Step S9.3, if Determine if the bridge meets the traffic capacity under batch load conditions; if It can be determined that the bridge does not meet the traffic capacity under batch load conditions;

[0113] Step S9.4, verify the first dynamic deflection coefficient at each measuring point. Take the average value. If the average value is less than 1, it indicates that the bridge deck load is within the design bearing capacity of the bridge structure.

[0114] It also includes: establishing a bridge safety early warning and automatic report output module, which displays in real time the vehicle parameters and position parameters of heavy vehicles, the measured dynamic deflection values ​​collected at each measuring point, and the calculated first and second dynamic deflection verification coefficients; if the first or second dynamic deflection verification coefficient is greater than 1, an early warning prompt is given; the automatic report output includes: bridge overview, monitoring and calculation basis, lightweight monitoring scheme layout, bridge theoretical calculation model, measured data and analysis, bridge passability results, traffic suggestions and attachments.

[0115] This invention also provides a lightweight monitoring and rapid evaluation and analysis system for small and medium span highway bridges, the logic framework diagram of which is shown below. Figure 1 This system can be divided into six modules: a bridge parametric rapid input module, a vehicle load batch input module, a measuring point information layout module, a finite element calculation and analysis module, a batch load condition measuring point result automatic extraction module, and a cloud-based highway bridge structural response monitoring module. To effectively accommodate the networked requirements of bridge structural modeling, calculation and analysis, data acquisition, decision-making, and operation management, a cross-platform approach combining PC and cloud is adopted to deploy the various functional modules. The specific technical points of each module are as follows:

[0116] The bridge parameterization rapid input module provides a bridge parameter input interface and interface. Most small- and medium-span highway bridges are prefabricated beam bridges, such as hollow slabs, T-beams, small box girders, and cast-in-place beams. Specifically, it is used for: 1) establishing a database of bridge structure sections under different spans and bridge deck widths based on general library drawings; 2) constructing a parameter customization interface for parameters such as span, material, bridge deck width, and section form; 3) constructing a bridge structure parameter definition interface based on the above parameters. Key parameters are listed below. Figure 1 Establish a bridge structural parameter data model; to meet the diverse needs of bridge structures, support the establishment and modification of the bridge structural parameter data model.

[0117] The vehicle load batch input module is used to acquire and input the position data of vehicles on the bridge deck at fixed steps in real time. Parameters are as follows: Figure 1 As shown, it is specifically used for: 1) establishing a customizable and visual interface for load parameters including axle load, wheelbase, track width, speed, etc.; 2) establishing a data transmission interface with the cloud-based vehicle recognition system module, supporting multiple input formats (Excel, JSON, direct database connection, etc.).

[0118] The measuring point information layout module enables the layout of measuring points for on-site measurement of dynamic deflection and static displacement of the bridge, so as to fully test the response characteristics of the bridge under load; specifically used for: 1) establishing measuring point parameters (see...) Figure 1The algorithm includes: 1) a customized and visual interface; 2) an intelligent recommended test section algorithm based on the principle of the most unfavorable section and the influence line method; and 3) an automatic bridge measuring point layout algorithm based on the cross-sectional characteristics and the bridge spatial mechanical response test requirements, combined with the measuring point layout requirements.

[0119] The finite element analysis module provides static and dynamic calculation and analysis functions for bridge structures, specifically for: 1) obtaining the design load effect value of the test section based on the influence line method using a standard vehicle load (35t, three-axle vehicle) and establishing the vehicle load case of the design load; 2) establishing a three-dimensional spatial node element relationship matrix, displacement compatibility equation, node load value, etc., based on a three-dimensional spatial mesh generation dynamic link library (DLL) for the bridge parameterized rapid input module and the vehicle load batch input module, and outputting a finite element analysis file (JFDJ) that meets the calculation format requirements; 3) calculating the static response results of the bridge structure under multiple load cases based on the finite element calculation kernel; and 4) calculating the theoretical impact coefficient of the bridge structure based on a planar truss model. ;

[0120] The automatic extraction module for batch load condition measurement point results extracts the theoretical calculation results of each measurement point under each load condition in batches based on the finite element calculation and analysis results of the finite element calculation and analysis module. Specifically, it is used for: 1) establishing a bridge spatial three-dimensional coordinate information conversion algorithm based on the data from the measurement point information layout module; 2) locating the entity element where the measurement point is located based on the spatial position geometry algorithm; 3) establishing the displacement derivation relationship of the measurement point based on the nodal displacement results of the entity element and the distance weight relationship between the measurement point and the entity element; 4) establishing a data display interface for the measurement point results and a data visualization interface for each load condition.

[0121] The cloud-based highway bridge structural response monitoring module enables real-time acquisition of on-site vehicle and measuring point data, real-time analysis of bridge dynamic verification coefficients, and bridge safety early warning functions. It mainly includes a vehicle weighing system, a vehicle position identification system, and a dynamic deflection monitoring system, as detailed below:

[0122] 1) Based on the characteristics of the bridge structure, a dedicated machine intelligent vision camera is deployed, combined with a vehicle weighing system and a vehicle position recognition system, to establish functions such as real-time identification, collection and transmission of vehicle positions on the bridge deck;

[0123] 2) Based on the need for real-time acquisition and visualization of bridge measurement point data, a parameterized definition interface was established;

[0124] 3) Establish modules for transmitting theoretical data of bridge measuring points, correcting measured data (see Formula 1), and automatically calculating verification coefficients (see Formulas 2, 3, and 4);

[0125] (1)

[0126] (2)

[0127] (3)

[0128] (4)

[0129] The meanings of each parameter in the formula are detailed in the preceding description.

[0130] if Determine if the bridge meets the traffic capacity under batch load conditions; if It can be determined that the bridge does not meet the traffic capacity under batch load conditions;

[0131] 4) Based on the above calculation results, establish modules for bridge safety early warning and automatic report output, particularly in real-time display of heavy vehicle information and its location, measuring points and collected information, theoretical measurement values ​​and safety factors. When any of the aforementioned safety factors... , When the value is greater than 1, an early warning will be issued. The report output mainly includes: bridge overview, monitoring and calculation basis, lightweight monitoring scheme layout, bridge theoretical calculation model, measured data and analysis, passability results, traffic recommendations, and attachments.

[0132] Taking a 1×30m ​​simply supported T-beam as an example, with a bridge deck width of 8m and 4 main beams, the specific implementation plan for each module of the above-mentioned lightweight testing and rapid evaluation method and integrated software system for small and medium span bridges is as follows:

[0133] 1. Select and deploy vehicle weighing system and vehicle location identification system, with technical parameters as described in the key points of the above technical solution;

[0134] 2. Calibrate the vehicle weighing system and vehicle location identification system. For specific steps, please refer to the key points of the above technical solution.

[0135] 3. Select the mid-span section as the test section, and install dynamic deflection gauges at the bottom of each beam. See the diagram for the measurement point layout. Figure 2 ;

[0136] 4. Establish a finite element model of the bridge. See the model rendering below. Figure 3 The theoretical impact coefficient of the calculation model =0.242;

[0137] 5. On-site data acquisition: Based on the vehicle weighing system and vehicle position recognition system, collect the real-time position set of two heavy vehicles A and B with a single axle weight greater than 8t on the bridge deck. , and , (t is the sampling point number within the sampling time range), and the corresponding measured dynamic deflection value of the measuring point, etc., and corrected according to the key points of the above technical solution to obtain the measured dynamic deflection value. The specific data collected on-site are shown in Table 1 below;

[0138] Table 1. On-site data collected from heavy vehicles on bridges.

[0139] 6. Input the vehicle parameters and corresponding real-time vehicle location sets collected in step 5 into the finite element model established in step 4, and calculate the theoretical deflection values ​​of the bridge at each measuring point under the combined action of heavy vehicle loads (A and B). ;

[0140] 7. Calculate the bridge dynamic deflection verification coefficient according to the key points of the above technical solution, and evaluate the vehicle passability results. The results are shown in Table 2 below. The calculation results show that the verification coefficient at the measuring point is 0.87, and the actual bearing capacity of the bridge meets the current vehicle traffic requirements.

[0141] Table 2. Results of Bridge Heavy Vehicle Passability Assessment

[0142] This invention proposes a method and system for lightweight monitoring and rapid evaluation analysis of small- and medium-span highway bridges based on real-time monitoring data. The technical advantages of this method are as follows:

[0143] 1. There is no need to carry out on-site collection of bridge appearance quality, material performance testing, dynamic characteristic testing, etc. Based on the standardized structural characteristics of small and medium span bridges, the safety coefficient of the bridge can be evaluated in real time by only monitoring the dynamic deflection of the measuring points at key cross-sections, thus realizing the real-time evaluation results.

[0144] 2. Without the need to close traffic to conduct bridge load tests or conduct specific test vehicle flow-limited load tests, it can accurately calculate the real-time dynamic verification coefficient of bridges under different driving conditions for various types of overweight vehicles under any traffic flow conditions, and provide timely safety warnings. This reduces the impact of traffic closures or flow restrictions, saves a lot of manpower and material resources required for load tests, and greatly reduces costs.

[0145] This invention provides a method for lightweight detection and rapid evaluation of small-to-medium span bridges. Compared to existing technologies, this method eliminates the need for on-site bridge appearance quality collection, material performance testing, and dynamic characteristic testing. It requires only a small number of sensors to achieve real-time assessment of the actual overweight vehicle traffic capacity of the bridge deck, improving the accuracy and real-time nature of the assessment results. Furthermore, compared to bridge load tests and specific test vehicle flow-limited load tests, this invention supports accurate calculation of the bridge's real-time dynamic verification coefficient under various traffic flow conditions and different driving conditions for various types of overweight vehicles, and provides timely safety warnings. This reduces the impact of traffic closures or flow restrictions, saves significant manpower and material resources required for load tests, and greatly reduces costs.

[0146] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for monitoring and rapid evaluation of lightweighting of small-to-medium span highway bridges, characterized in that, Includes the following steps: Step S1: Select and deploy a vehicle weighing system and a vehicle position recognition system based on the characteristics of the bridge structure; Step S2: Calibrate the vehicle weighing system and the vehicle position recognition system respectively to obtain the calibrated vehicle weighing system and the vehicle position recognition system; Step S3: Select the test section and set up the corresponding test sections. One measuring point; each measuring point Deploy wireless deflectometers; ; Step S4: Establish the finite element model of the bridge; Step S5, On-site data acquisition: Step S5.1: Determine the sampling frequency; synchronously start the vehicle weighing system, the vehicle position recognition system, and each measuring point within the sampling time range. The wireless torsion gauges that have been deployed; Step S5.2, at each sampling point within the acquisition time range The vehicle weighing system obtains the vehicle parameters of each overweight vehicle traveling on the bridge; the vehicle position recognition system obtains the vehicle position parameters of each overweight vehicle traveling on the bridge; each sampling point The vehicle parameters and vehicle position parameters of all overweight vehicles form a batch load condition acting on the bridge deck. ; Step S5.3, at each sampling point within the acquisition time range The wireless torsion gauge is used to obtain the readings for each measuring point. under batch load conditions Measured dynamic deflection value at the measuring point under action ; Step S6, for each sampling point The obtained batch load conditions The theoretical impact coefficient is obtained by inputting the data into the finite element model of the bridge and using the spatial finite element method. ; Based on the bridge finite element model, batch load cases were obtained respectively. Static displacement of measuring point under load and measuring points under design load static load displacement of measuring points ; Step S7: Use formula (1) to measure the dynamic deflection value at the measuring point. After correction, the measured dynamic deflection value at the measuring point is obtained. : （1） Step S8: Using formulas (2) and (3), the verification coefficients of the first dynamic deflection at the measuring point are obtained respectively. and the second dynamic deflection verification coefficient at the measuring point : （2） （3） Step S9, verify the first dynamic deflection coefficient at the measuring point. and the second dynamic deflection verification coefficient at the measuring point Determine whether the bridge meets the current batch load conditions. Traffic capacity.

2. The method for lightweight monitoring and rapid evaluation analysis of small-to-medium span highway bridges according to claim 1, characterized in that, The vehicle weighing system is used to identify the vehicle parameters of overweight vehicles passing on the bridge deck, including axle load, wheelbase, and track width; the vehicle position identification system is used to measure the vehicle position parameters of overweight vehicles on the bridge deck in real time based on the bridge axle support baseline, including the bridge deck station number of the vehicle's front axle center, support distance, and direction of travel; the support distance is the distance between the vehicle center and the bridge deck centerline.

3. The method for lightweight monitoring and rapid evaluation analysis of small-to-medium span highway bridges according to claim 1, characterized in that, The vehicle weighing system and the vehicle position recognition system are calibrated respectively to obtain the calibrated vehicle weighing system and vehicle position recognition system, specifically as follows: Step S2.1: Select a calibration vehicle with a weight of not less than 35t and equipped with a vehicle position indicator; Step S2.2: Measure and calibrate the vehicle's geometric parameters, including wheelbase and track width; Step S2.3: Weigh the calibrated vehicle to accurately obtain the axle weight of each axle and the total axle weight. Step S2.4, conduct testing using a calibrated vehicle: During periods of low traffic, the calibration vehicle was idling through each lane of the bridge in sequence, ensuring no interference from other vehicles during the test. While the calibration vehicle was passing through, its vehicle position indicator collected the vehicle position parameters on the bridge surface in real time. Simultaneously, the vehicle position recognition system was activated to measure the vehicle position parameters of the calibration vehicle as it passed through the bridge surface in real time. While the calibration vehicle was passing through, the vehicle weighing system measured the vehicle parameters of the calibration vehicle. Step S2.5, Vehicle weighing system calibration: The vehicle parameters of the calibrated vehicle measured by the vehicle weighing system are compared with the vehicle parameters measured in steps S2.2 and S2.3, and the vehicle weighing system is calibrated based on the difference. Step S2.6, Vehicle location recognition system calibration: The vehicle position parameters measured in real time by the vehicle position recognition system are compared with those collected in real time by the vehicle position indicator, and the vehicle position recognition system is calibrated based on the difference.

4. The method for lightweight monitoring and rapid evaluation analysis of small-to-medium span highway bridges according to claim 1, characterized in that, Selecting the test section and setting up the corresponding test section There are 1 measuring point, specifically: Based on the displacement influence line method, the section with the largest deformation of the main beam is selected as the test section; A measuring point is set at the bottom of each beam directly below the test section. For beams with... Bridges with a single main girder, layout There are 10 measurement points.

5. The method for lightweight monitoring and rapid evaluation analysis of small-to-medium span highway bridges according to claim 1, characterized in that, The establishment of the bridge finite element model specifically involves: Based on a general cross-section library of small and medium-span bridges, a parametric method is adopted, combined with cross-section mesh generation, hexahedral geometric stretching, and nodal displacement coordination algorithms, to build a rapid modeling assistant and establish a planar model of small and medium-span bridges and a corresponding three-dimensional solid space finite element model.

6. The method for lightweight monitoring and rapid evaluation analysis of small-to-medium span highway bridges according to claim 1, characterized in that, The method for determining the sampling frequency is as follows: The sampling frequency of the bridge during the average daily peak traffic period was calculated. ;in, The speed of the loaded vehicle; This is the sampling step size; Take the maximum value of the sampling frequency during the average daily peak period of the vehicle. , which serves as the determined sampling frequency.

7. The method for lightweight monitoring and rapid evaluation analysis of small-to-medium span highway bridges according to claim 1, characterized in that, Based on the finite element model of the bridge, batch load cases were obtained. Static displacement of measuring point under load Also known as batch load case The theoretical dynamic deflection value of the measuring point under action is as follows: Batch load conditions Input the finite element model of the bridge, convert the vehicle axle loads into nodal forces, and simultaneously apply them to the finite element model according to the positions of each vehicle. Based on the spatial finite element method, calculate the bridge deck under batch load conditions. Static displacement of measuring point under load .

8. The method for lightweight monitoring and rapid evaluation analysis of small-to-medium span highway bridges according to claim 1, characterized in that, Based on the dynamic verification coefficient of the measuring point and real-time dynamic verification coefficients of measuring points Determine whether the bridge meets the current batch load conditions. The following are the traffic capacities: Step S9.1, for each measuring point , Each sampling point within the collection time range The second dynamic deflection verification coefficient was obtained for all measurement points, and the same sampling point was used. The maximum value of the second dynamic deflection verification coefficient at each measuring point is the sampling point. Corresponding maximum dynamic deflection verification coefficient ; Step S9.2, according to formula (4), for each sampling point within the collection time range Maximum dynamic deflection verification coefficient The average value is used to obtain the second dynamic deflection verification coefficient of the bridge. : （4） in: This refers to the number of sampling points within the data collection time range. Step S9.3, if Determine if the bridge meets the traffic capacity under batch load conditions; if It can be determined that the bridge does not meet the traffic capacity under batch load conditions; Step S9.4, verify the first dynamic deflection coefficient at each measuring point. Take the average value. If the average value is less than 1, it indicates that the bridge deck load is within the design bearing capacity of the bridge structure.

9. The method for lightweight monitoring and rapid evaluation analysis of small-to-medium span highway bridges according to claim 1, characterized in that, Also includes: Establish a bridge safety early warning and automatic report output module to display in real time the vehicle parameters and vehicle position parameters of heavy vehicles, the measured dynamic deflection value collected at each measuring point, and the calculated first dynamic deflection verification coefficient and second dynamic deflection verification coefficient. If the first dynamic deflection verification coefficient or the second dynamic deflection verification coefficient is greater than 1, an early warning will be given. The report automatically outputs the following content: bridge overview, monitoring and calculation basis, lightweight monitoring scheme layout, bridge theoretical calculation model, measured data and analysis, bridge passability results, traffic recommendations and attachments.

10. A system for implementing the lightweight monitoring and rapid evaluation analysis method for small-to-medium span highway bridges as described in any one of claims 1 to 9, characterized in that, include: The system includes a bridge parameterized rapid input module, a vehicle load batch input module, a measuring point information layout module, a finite element calculation and analysis module, a batch load condition measuring point result automatic extraction module, and a cloud-based highway bridge structural response monitoring module. The bridge parameterization rapid input module provides a bridge parameter input interface and interface, specifically used for: 1) establishing a database of various cross-sections of the bridge structure under different spans and bridge deck widths based on general library drawings; 2) constructing a parameter customization interface for span, material, bridge deck width, and cross-sectional form; 3) constructing a bridge structure parameter definition interface and establishing a bridge structure parameter data model; to meet the diverse needs of bridge structures, it supports the creation and modification of the bridge structure parameter data model; The vehicle load batch input module is used to acquire and input the position data of vehicles on the bridge deck at fixed steps in real time. Specifically, it is used to: 1) establish a customizable and visual interface for load parameters including axle load, wheelbase, track width, and speed; 2) establish a data transmission interface with the cloud-based vehicle recognition system module, supporting multi-format input. The measuring point information arrangement module enables the arrangement of measuring points for on-site measurement of dynamic deflection and static displacement of the bridge, so as to test the response characteristics of the bridge under load. Specifically, it is used for: 1) establishing a customizable and visual interface for measuring point parameters; 2) establishing an intelligent algorithm for recommending test sections based on the principle of the most unfavorable section and using the influence line method; 3) establishing an automatic bridge measuring point layout algorithm based on the cross-sectional characteristics and the requirements for bridge spatial mechanical response testing, combined with the requirements for measuring point layout. The finite element calculation and analysis module provides static and dynamic calculation and analysis functions for bridge structures, specifically used for: 1) obtaining the design load effect value of the test section based on the influence line method and using standard vehicle loads, and establishing the vehicle load case of the design load. 2) For the bridge parameterized rapid input module and the vehicle load batch input module, based on the three-dimensional spatial mesh division dynamic link library, a three-dimensional spatial node element relationship matrix, displacement compatibility equation, and node load value are established, and a finite element calculation analysis file that meets the calculation format requirements is output; 3) Based on the finite element calculation kernel, the static response results of the bridge structure under multiple working conditions are calculated. 4) Calculate the theoretical impact coefficient of the bridge structure based on the planar frame model. ; The automatic extraction module for batch load condition measurement point results extracts the theoretical calculation results of each measurement point under each load condition in batches based on the finite element calculation and analysis results of the finite element calculation and analysis module. Specifically, it is used for: 1) establishing a bridge spatial three-dimensional coordinate information conversion algorithm based on the data from the measurement point information layout module; 2) locating the entity element where the measurement point is located based on the spatial position geometry algorithm; 3) establishing the displacement derivation relationship of the measurement point based on the nodal displacement results of the entity element and the distance weight relationship between the measurement point and the entity element; 4) establishing a data display interface for the measurement point results and a data visualization interface for each load condition. The cloud-based highway bridge structure response monitoring module enables real-time acquisition of on-site vehicle data and measuring point data, real-time analysis of bridge dynamic verification coefficients, and bridge safety early warning functions. It mainly includes a vehicle weighing system, a vehicle position identification system, and a dynamic deflection monitoring system.

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