Small and medium-sized bridge safety diagnosis method and system based on spatial discrete axle load and displacement monitoring data

Abstract

The invention relates to the technical field of bridge monitoring, in particular to a small and medium-sized bridge safety diagnosis method and system based on spatial discrete axle load and displacement monitoring data. According to the method, a space-time distribution matrix of the vehicle axle load of the actual traffic flow on the multi-beam medium and small bridges is established based on a data driving method, an implementation process for converting time-discontinuous discrete dynamic weighing monitoring data into a time sequence of the vehicle axle load is provided, and reference is provided for engineering application. According to the method, the bridge is divided according to longitudinal areas to realize linkage calculation of a time sequence of vehicle axle load and theoretical displacement values of key sections of any main beams of the medium and small bridges, and displacement-based safety condition evaluation indexes of the medium and small bridges are established by combining displacement monitoring data of key sections of the medium and small span bridges. According to the method, the bridge health monitoring data are effectively mined, the rationality and reliability of bridge safety evaluation are effectively improved, and the technical level of a bridge health monitoring system is improved.

Description

Technical Field

[0001] This invention relates to the field of bridge monitoring technology, and in particular to a method and system for safety diagnosis of small and medium-sized bridges based on spatial discrete axle load and displacement monitoring data. Background Technology

[0002] Small and medium-span bridges are important infrastructure in transportation, accounting for more than 90% of the total number of bridges in my country. With the combined effects of continuous traffic loads, environmental erosion, and natural aging of materials, the structural safety and durability of small and medium-span bridges gradually decrease as the operation period increases.

[0003] To ensure the safe operation of small and medium-span bridges, timely and accurate diagnosis of their safety status is essential. Static load testing of bridges involves loading the bridge with the design load level and measuring the deformation of the bridge structure before, during, and after loading. The test results are used to determine the service condition of the bridge structure. However, the maintenance budget for small and medium-sized bridges is limited, and the preparation and testing process for static load tests require significant manpower and resources. More importantly, the testing cycle of this method is not fixed, and it cannot reflect the bridge's safety status in real time. Because it is designed for sudden accidents, it cannot achieve the effect of timely diagnosis of the bridge's safety status.

[0004] With the rapid development of information technology, bridge health monitoring technology has been gradually introduced into the maintenance process of bridges during their operational phase. By installing sensors on-site, structural response parameters such as displacement, strain, and vibration of the bridge can be monitored in real time, reflecting the long-term changing trends of the bridge's internal forces. Furthermore, lightweight health monitoring of small- and medium-span bridges is a strategic deployment of the Ministry of Transport. Therefore, given the massive amount of data from bridge health monitoring, fully mining this data is a major trend in structural safety assessment. Chinese invention patent CN112762885B discloses a method for calculating the real-time deflection verification coefficient of bridges based on monitoring data, which mines the monitoring data to a certain extent, but it does not explain how dynamic weighing data is used to calculate the bridge's deflection value, thus limiting its application in engineering.

[0005] To address the aforementioned issues and to fully utilize existing monitoring data for small- and medium-span bridges, aiming to more accurately diagnose the safety status of bridges, this invention integrates multi-source monitoring data and adopts a combined mechanical and data-driven approach to propose a safety diagnosis method and system for small- and medium-span bridges based on spatially discrete axle load and displacement monitoring data. Summary of the Invention

[0006] To address the problems in existing technologies, this invention provides a method and system for safety diagnosis of small and medium-sized bridges based on spatial discrete axle load and displacement monitoring data. The specific technical solution is as follows: A safety diagnosis method for small and medium-sized bridges based on spatial discrete axle load and displacement monitoring data includes the following steps: Step S1: Collect discrete vehicle weight data monitored by the weighing system on the bridge and establish a spatiotemporal distribution matrix of vehicle axle load on the bridge. Step S2: Calculate the theoretical displacement values ​​of key sections at mid-span of small- and medium-span bridges under unit moving load, and establish the influence matrix of theoretical displacement values ​​under unit moving load. Step S3: Calculate the theoretical displacement of key sections of the main beam of small and medium-sized bridges under real-time vehicle action based on the axle load spatiotemporal distribution matrix and the displacement theoretical value influence matrix. Step S4: Real-time acquisition of measured displacement values ​​at key cross-sections at mid-span of small and medium-sized bridges; Step S5: Calculate the safety status evaluation index of small and medium-sized bridges based on theoretical displacement calculation values ​​and measured displacement values, and diagnose the safety status of small and medium-sized bridges.

[0007] Preferably, step S1, which involves collecting discrete vehicle weight data monitored by the weighing system on the bridge and establishing a spatiotemporal distribution matrix of vehicle axle load on the bridge, specifically includes the following steps: Step S11, set the start time as Analysis time is The analysis time step is Number of time periods divided Establish analysis duration Corresponding time series matrix ; Step S12, in the established time series matrix The middle determines the first The time when the car appeared on the bridge was obtained. Time series matrix of vehicles appearing on the bridge ; Step S13, let the length of the bridge be... The starting point of the bridge is 0, and the ending point of the bridge is... The bridge has N lanes. Calculate the number of lanes for each lane. The first axle of the vehicle after entering the bridge is in the time series matrix The i-th time point Location on the bridge ; Step S14, according to the first The first axle of the vehicle after entering the bridge is in the time series matrix The i-th time point Location on the bridge Calculate the first The remaining axles of the vehicle at time point i Location on the bridge surface; Step S15: Divide the small and medium-sized bridges along their length into... Each region is divided into several areas, and the length of each area is... = 1 / 450~ 1 / 250; Step S16: For a bridge with n lanes, transfer the first lane number of each lane to the first lane. Each axle of the vehicle at time point i The location of the bridge deck and the division The location ranges of each region are matched to obtain the time series matrix. The i-th time point Down The axis redistribution data for each region is used to obtain the time series matrix. The i-th time point Spatiotemporal distribution matrix of axle load of vehicles on bridge The details are as follows: ; In the formula, This represents the spatiotemporal distribution matrix of axle load when a vehicle is traveling in the nth lane at the i-th time point; ; in, Let represent the total axle load of vehicles in the k-th region when the vehicle is traveling in the n-th lane at time i, where n = 1, ..., N.

[0008] Preferably, in step S12, the established time series matrix The middle determines the first The exact time when the vehicle appeared on the bridge is as follows: ; in, This refers to the distance between the dynamic weighing system and the starting point of the bridge. For the first The speed of the vehicle, For the first The time it takes for a vehicle to pass through the dynamic weighing system. For the first The length of the vehicle; Find(*) is the Find function in MATLAB.

[0009] Preferably, in step S13, the calculation of the first lane is performed. After the vehicle enters the bridge, in the time series matrix The i-th time point Location on the bridge Specifically as follows: No. After the vehicle enters the bridge from the starting point along the lane direction, the first The first axle of the vehicle after it enters the bridge is in the time series matrix. The i-th time point Location on the bridge The calculation method is as follows: ; No. After the vehicle enters the bridge from the end of the bridge along the lane direction, the first The first axle of the vehicle after it enters the bridge is in the time series matrix. The i-th time point Location on the bridge The calculation method is as follows: .

[0010] Preferably, in step S14, according to the first The first axle of the vehicle after it enters the bridge is in the time series matrix. The i-th time point Location on the bridge Calculate the first The remaining axles of the vehicle at time point i The specific location on the bridge surface is as follows: Let the first The car has B axles, the first... The distance between the first axle and the b-th axle of the vehicle is ,but: No. When a vehicle enters the bridge from the starting point along the lane direction, the position of the b-th axle is... ; No. When a vehicle enters the bridge from the end of the bridge along the lane direction, the position of the b-th axle is... , where b=2,···,B.

[0011] Preferably, step S2 specifically includes the following steps: Step S21: Establish the bridge finite element model using the beam grid method, and follow... 1 / 450~ Divide the unit into units of 1 / 250 of its length; Step S22: Calculate the displacement response of the key section of the small bridge under unit load movement. Divide the bridge into actual lanes and apply a unit concentrated load according to the actual lane conditions. Establish the load case of the unit concentrated load moving back and forth on the lanes. Calculate the theoretical displacement value of the key section of the a-th main beam when it reaches the k-th region during the unit concentrated load movement process. ; Step S23: Establish the theoretical displacement matrix of the key section of the main beam when the unit moving load of the a-th main beam is applied to the n-th lane. The details are as follows: ; Where T represents transpose.

[0012] Preferably, the theoretical displacement calculation values ​​of key sections of the main beam of small and medium-sized bridges under real-time action of actual vehicles in step S3, based on the axle load spatiotemporal distribution matrix and the displacement theoretical value influence matrix, are as follows: Time series matrix The i-th time point Theoretical displacement calculation value of the key section of the a-th main beam of small and medium-sized bridge The calculation method is as follows: ; Where N is the number of lanes the bridge is divided into according to the actual number of lanes.

[0013] Preferably, step S5, which involves calculating the safety status evaluation index of small and medium-sized bridges based on theoretical displacement calculations and measured displacement values, and diagnosing the safety status of the small and medium-sized bridges, specifically includes the following steps: The safety status evaluation index for small and medium-sized bridges based on displacement is calculated as follows: ; in, Representing a time series matrix The i-th time point Safety evaluation indicators for the critical section of the a-th main girder of small and medium-sized bridges; Representing a time series matrix The i-th time point Measured displacement value of the key section of the a-th main beam of a small and medium-sized bridge; Representing a time series matrix The i-th time point Theoretical displacement calculation value of the key section of the a-th main beam of a small and medium-sized bridge; when When, it represents the time series matrix. The i-th time point The measured displacement value of the critical section of the a-th main beam of the small and medium-sized bridge is less than the theoretical calculation value, and the structural condition is diagnosed as safe. when When, it represents the time series matrix. The i-th time point The measured displacement value of the critical section of the a-th main beam of the small and medium-sized bridge is greater than or equal to the theoretical calculation value, and the structural condition is diagnosed as unsafe.

[0014] A safety diagnostic system for small and medium-sized bridges based on spatial discrete axle load and displacement monitoring data, comprising the following methods: The axle load spatiotemporal distribution matrix establishment module is used to collect discrete vehicle weight data monitored by the weighing system on the bridge and establish the axle load spatiotemporal distribution matrix of the vehicle on the bridge. The displacement theory value influence matrix establishment module is used to calculate the theoretical displacement value of key sections at the mid-span of small and medium-span bridges under unit moving load and to establish the displacement theory value influence matrix under unit moving load. The theoretical displacement calculation module is used to calculate the theoretical displacement of key sections of the main beam of small and medium-sized bridges under real-time vehicle action based on the axle load spatiotemporal distribution matrix and the displacement theoretical value influence matrix. The measured displacement acquisition module is used to collect the measured displacement values ​​of key sections at the mid-span of small and medium-sized bridges in real time. The safety diagnosis module is used to calculate displacement-based safety status evaluation indicators for small and medium-sized bridges based on theoretical displacement calculations and measured displacement values, and to diagnose the safety status of small and medium-sized bridges.

[0015] An electronic device includes a memory and a processor, the memory storing a computer program, and the processor running the computer program to enable the electronic device to perform the aforementioned method for safety diagnosis of small and medium-sized bridges based on spatial discrete axle load and displacement monitoring data.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention establishes a spatiotemporal distribution matrix of vehicle axle load on multi-beam small and medium-sized bridges based on a data-driven approach, and proposes an implementation process for converting discrete dynamic weighing monitoring data that is not time-seriesed into a time sequence of vehicle axle load, providing a reference for engineering applications.

[0017] This invention divides bridges into longitudinal regions to achieve the linkage calculation of vehicle axle load time sequence and theoretical displacement value of any key section of main beam of small and medium-sized bridges. Combined with displacement monitoring data of key sections of small and medium-span bridges, a displacement-based safety status evaluation index for small and medium-sized bridges is established.

[0018] This invention effectively mines bridge health monitoring data, fully utilizes the value of multi-source monitoring data, provides an innovative method for bridge safety diagnosis, effectively improves the rationality and reliability of bridge safety evaluation, and enhances the technical level of bridge health monitoring systems. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0020] Figure 1 This is a flowchart of the method of the present invention.

[0021] Figure 2 This is a comparison diagram of vehicle positions in an embodiment of the present invention.

[0022] Figure 3 This is a diagram showing the axle load distribution in each area of ​​lane 1 at time t=16.5s.

[0023] Figure 4 This is a diagram showing the axle load distribution in each area of ​​the second lane at time t=16.5s.

[0024] Figure 5 This is a schematic diagram of a finite element model of a bridge.

[0025] Figure 6 This is a diagram of the moving load parameter interface, in which... Figure 6 (a) is a diagram of the vehicle load parameters interface. Figure 6 (b) is a diagram of the parameters for the moving load condition.

[0026] Figure 7 This is a diagram showing the concentrated load conditions for a single unit.

[0027] Figure 8 This is a screenshot of the interface for setting parameters for influence line calculation.

[0028] Figure 9 This is a schematic diagram of the displacement influence lines in a finite element model.

[0029] Figure 10 This is the influence line of the mid-span displacement of each main beam in the left lane.

[0030] Figure 11 This is the influence line of the mid-span displacement of each main beam in the right lane.

[0031] Figure 12 This is the time history curve of the mid-span displacement of the first main beam.

[0032] Figure 13The time history curves show the mid-span displacement of each main beam.

[0033] Figure 14 The time history curves of the measured displacement at mid-span of each main beam are shown.

[0034] Figure 15 This is a graph showing the relationship between the measured displacement and the theoretical displacement at mid-span of the first main beam.

[0035] Figure 16 This is the time history curve of the safety status of the first main girder bridge.

[0036] Figure 17 This is a system schematic diagram of the present invention. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0039] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0040] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0041] Example 1: like Figure 1 As shown, this embodiment provides a safety diagnosis method for small and medium-sized bridges based on spatial discrete axle load and displacement monitoring data, including the following steps: Step S1 involves collecting discrete vehicle weight data monitored by the weighing system on the bridge and establishing a spatiotemporal distribution matrix of vehicle axle load on the bridge. This includes the following steps: Step S11, set the start time as Analysis time is The analysis time step is The number of time periods divided, c Establish analysis duration Corresponding time series matrix Then the time series matrix as follows: ;(1).

[0042] In this embodiment, the analysis starts at time . Analysis time is The analysis time step is Number of time periods divided Establish analysis duration Corresponding time series matrix as follows: .

[0043] Step S12, in the established time series matrix The middle determines the first The time when the car appeared on the bridge was obtained. Time series matrix of vehicles appearing on the bridge In the established time series matrix The middle determines the first The exact time when the vehicle appeared on the bridge is as follows: ; in, This refers to the distance between the dynamic weighing system and the starting point of the bridge. For the first The speed of the vehicle, For the first The time it takes for a vehicle to pass through the dynamic weighing system. For the first The length of the vehicle. Find(*) is the MATLAB Find function. Using the MATLAB Find function, you can obtain the length of the vehicle. The time points when the vehicle appeared on the bridge were recorded and constructed into a time series matrix. submatrix .

[0044] Step S13, let the length of the bridge be... The starting point of the bridge is 0, and the ending point of the bridge is... The bridge has N lanes. Calculate the first lane number for each lane. After the vehicle enters the bridge, the first axle in the time series matrix The i-th time point Location on the bridge The details are as follows: No. After the vehicle enters the bridge from the starting point along the lane direction, the first The first axle of the vehicle after it enters the bridge is in the time series matrix The i-th time point Location on the bridge The calculation method is as follows: ; No. After the vehicle enters the bridge from the end of the bridge along the lane direction, the first The first axle of the vehicle after it enters the bridge is in the time series matrix The i-th time point Location on the bridge The calculation method is as follows: .

[0045] Step S14, according to the first The first axle of the vehicle after entering the bridge is in the time series matrix The i-th time point Location on the bridge Calculate the first The remaining axles of the vehicle at time point i The location on the bridge surface is as follows: Let the first The car has B axles, the first... The distance between the first axle and the b-th axle of the vehicle is ,but: No. When a vehicle enters the bridge from the starting point along the lane direction, the position of the b-th axle is... Taking a four-axle vehicle as an example, the distances between the first axle and the second, third, and fourth axles of the four-axle vehicle are respectively... , , Then the first Each axle of the vehicle The locations on the bridge surface at each time point are respectively , , , .

[0046] No. When a vehicle enters the bridge from the end of the bridge along the lane direction, the position of the b-th axle is: Where b = 2, ..., B. Taking a four-axle vehicle as an example, the first axle / the second axle, the third axle, and the fourth axle are... The locations on the bridge surface at each time point are respectively , , , .

[0047] Let the length of the bridge be... The distance between the dynamic weighing system and the starting point of the bridge is... The vehicle parameters are shown in Table 1.

[0048] Table 1 Vehicle Parameter Information Table From the established time series matrix The first one was selected from the middle The time points at which the vehicles appeared on the bridge were recorded and constructed into a time series matrix. submatrix As shown in Table 2. Submatrix In time series matrix In contrast, non-existent elements are filled with 0.

[0049] Table 2. Time information and time submatrix for each vehicle The time series matrix for each vehicle can be calculated using the formula. Each time point Location on the bridge deck ,like Figure 2 As shown.

[0050] Step S15: Divide the small and medium-sized bridges along their length into... Each region is divided into several areas, and the length of each area is... = 1 / 450~ 1 / 250.

[0051] Small and medium-span bridges have shorter single-span lengths, generally designed to be between 25 and 45 meters. In order to enable more precise analysis and calculation, the bridge length is divided at intervals of 0.1 meters.

[0052] The length of the bridge is The bridge length is divided into sections with intervals of 0.1 meters. There are several regions. Therefore, the regions are divided as follows: .

[0053] Step S16: For a bridge with n lanes, transfer the first lane number of each lane to the first lane. Each axle of the vehicle at time point i The location of the bridge deck and the division The location ranges of each region are matched to obtain the time series matrix. The i-th time point Down The axis redistribution data for each region is used to obtain the time series matrix. The i-th time point Spatiotemporal distribution matrix of axle load of vehicles on bridge The details are as follows: ; In the formula, This represents the spatiotemporal distribution matrix of axle load when a vehicle is traveling in the nth lane at the i-th time point; ; in, Let represent the total axle load of vehicles in the k-th region when the vehicle is traveling in the n-th lane at time i, where n = 1, ..., N.

[0054] Among them, determining the first in each lane Each axle of the vehicle at time point i The system checks whether the location on the bridge surface matches the location range of the k-th region, primarily by determining the position of the k-th region on each lane. Each axle of the vehicle at time point i Does the location on the bridge surface belong to the location range of the k-th region? If it does, then the corresponding lane... The vehicle's corresponding axle at time point i The location on the bridge surface matches the location range of the kth region.

[0055] Calculate the total axle load of vehicles in the k-th region when the vehicle is traveling in the n-th lane at time point i. Then, at time point i, the number of axles in the k-th region when a vehicle is traveling in the n-th lane is counted, and the axle loads of the counted axles are summed to obtain the total axle load of the vehicles in the k-th region when a vehicle is traveling in the n-th lane at time point i. .

[0056] For example, calculating the time point The axle load on the first lane is: Car 1: The position of the first axle: .

[0057] The position of the second axle: .

[0058] The position of the 3rd axle: .

[0059] The position of the 41st axle: Therefore, the position of the first axle of vehicle 1 is not within the bridge's defined section area.

[0060] The third car: The position of the first axle: .because It belongs to the 289th interval: Axle load is: .

[0061] The position of the second axle: .because It belongs to the 262nd interval: Axle load is: .

[0062] 5th car: The position of the first axle: .because It belongs to the 166th interval: Axle load is: .

[0063] The position of the second axle: .because It belongs to the 138th interval: Axle load is: .

[0064] The 7th car: The position of the first axle: .because It belongs to the 91st interval: Axle load is: .

[0065] The position of the second axle: .because It belongs to the 36th interval: Axle load is: .

[0066] The position of the 3rd axle: .because It belongs to the 23rd interval: Axle load is: .

[0067] therefore, , , , , , , The spatiotemporal distribution matrix of axle load is as follows: The calculation of axle load in the first lane is the same as above. , , , , , , The spatiotemporal distribution matrix of axle load is as follows: The axial weight distribution in each region at time t is as follows Figure 3 , Figure 4 As shown.

[0068] Analysis time Include At each time point, the analysis duration is established according to step S16. Corresponding full bridge Spatiotemporal distribution matrix of vehicle weight in each region .

[0069] .

[0070] Step S2 involves using theoretical analysis to calculate the theoretical displacement values ​​of key sections at mid-span of small-to-medium span bridges under a unit moving load, and establishing the influence matrix of the theoretical displacement values ​​under a unit moving load. This specifically includes the following steps: Step S21: Using Midas Civil finite element analysis software, a finite element model of the bridge is established using the beam grid method, and the model is constructed according to... 1 / 450~ The element size is divided into 1 / 250 lengths. In this embodiment, the element size is divided into 0.1m lengths, and material properties (such as elastic modulus, concrete design strength, Poisson's ratio, etc.) and constraint conditions are assigned to the model elements. The bridge finite element model is as follows: Figure 5 As shown.

[0071] Step S22: Calculate the displacement response of the key section of the small-to-medium bridge under unit load movement. Divide the bridge into lane 1 and lane 2 (left and right lanes) according to the actual lane conditions. Apply a unit concentrated load based on the actual lane conditions to establish a load case where the unit concentrated load moves back and forth on the lane. Load parameters are set as follows: Figure 6 As shown. The unit concentrated load case is as follows: Figure 7 As shown.

[0072] In the bridge influence line parameter interface, different lanes and nodes can be selected to draw the displacement influence line. For example, to calculate the displacement value of the mid-span section of a small bridge under a unit concentrated load, the lane can be selected as the right lane and the node number as 153, and the displacement influence line of the mid-span section of the small bridge can be obtained. Figure 8 The image shows the parameter settings interface for influence line calculation. Figure 9 The figure shows the influence line of displacement at the mid-span section of the bridge.

[0073] The theoretical displacement values ​​of the critical sections of the a-th main beam were calculated when it moved to the k-th region under a unit concentrated load. .

[0074] For those with For a bridge with multiple lanes, when a unit moving load in any lane moves longitudinally... When considering any region k in the given regions, calculate the theoretical displacement value of the key section of the main beam, taking the a-th main beam as an example.

[0075] (1) When the unit moving load is in the first lane, establish the load case of the unit concentrated load moving back and forth in the first lane, and calculate the theoretical displacement value of the key section of the a-th main beam when it reaches the k-th area during the unit concentrated load movement process. .

[0076] (2) When the unit moving load is in the second lane, establish the load case of the unit concentrated load moving back and forth in the second lane, and calculate the theoretical displacement value of the key section of the a-th main beam when it reaches the k-th area during the unit concentrated load movement process. .

[0077] (3) Calculate the unit moving load on the first When the first lane is reached, at the... Calculate the theoretical displacement of the critical section of the a-th main beam when it reaches the k-th region during the unit concentrated load movement process, under the load condition of a unit concentrated load moving back and forth in each lane. .

[0078] Step S23: Establish the theoretical displacement matrix of the key section of the main beam when the unit moving load of the a-th main beam is applied to the n-th lane. The details are as follows: ; Where T represents transpose.

[0079] Based on the above, a theoretical displacement matrix of the key cross-section at mid-span of the main girder of a small or medium-sized bridge can be established when a unit moving load is distributed across all lanes. Taking the a-th main girder as an example: .

[0080] This embodiment yields the following: Figure 10 The influence lines of the mid-span displacement of each main beam in the left lane are shown. Figure 11 The influence lines of the mid-span displacement of each main beam in the right lane are shown.

[0081] Step S3: Based on the axle load spatiotemporal distribution matrix and the influence matrix of theoretical displacement values, calculate the theoretical displacement values ​​of key sections of the main girder of the small and medium-sized bridge under the real-time action of actual vehicles. Details are as follows: Time series matrix The i-th time point Theoretical displacement calculation value of the key section of the a-th main beam of small and medium-sized bridge The calculation method is as follows: ; Where N is the number of lanes the bridge is divided into according to the actual number of lanes.

[0082] Based on the time point obtained in step S16 Spatiotemporal distribution matrix of vehicle axle load on bridge Since the bridge is designed for two lanes, the spatiotemporal distribution matrix of axle load is: and .in, This represents the total axle load of vehicles in zone 289 when the vehicle is traveling in lane 1 at time 16.5s.

[0083] Based on the displacement theoretical value matrix of the first main beam's mid-span critical section established in step S22 when the unit moving load is distributed across all lanes. and .

[0084] Therefore, it has the capability to calculate and analyze time series matrices. Mid-time point Theoretical displacement calculation value of the critical section of the first main girder of small and medium-sized bridges .

[0085] like Figure 12 The figure shows the time history curve of the mid-span displacement of the first main beam.

[0086] The theoretical displacement of the critical section of the a-th main beam under the action of the spatiotemporal distribution moment of vehicle weight is calculated in real time, with a setup time of [duration missing]. Corresponding real-time theoretical displacement calculation matrix .

[0087] Figure 13 The time history curves of the mid-span displacement of each main beam are obtained from the calculation.

[0088] Step S4: Real-time acquisition of measured displacement values ​​at key mid-span sections of the small and medium-sized bridge. Displacement sensors are installed at key mid-span sections of each main girder of the small and medium-sized bridge. The displacement sensors are multi-point image displacement measurement sensors with 200mm square passive targets, a sampling frequency ≥20Hz, and a measurement accuracy of ±0.2mm. The passive targets are installed at the bottom of each main girder mid-span section. The sampling frequency of the measured displacement is set to the time step of the displacement theoretical value analysis. This allows us to obtain the key cross-sections of each main beam of small and medium-sized bridges at any time point. Measured displacement value At any time point, the critical sections of the main beams of small and medium-sized bridges... Measured displacement value like Figure 14 As shown.

[0089] Step S5 involves calculating the safety status evaluation index for small and medium-sized bridges based on theoretical displacement calculations and measured displacement values, and diagnosing the safety status of the bridges. This specifically includes the following steps: The safety status evaluation index for small and medium-sized bridges based on displacement is calculated as follows: ; in, Representing a time series matrix The i-th time point Safety evaluation indicators for the critical section of the a-th main girder of small and medium-sized bridges; Representing a time series matrix The i-th time point Measured displacement values ​​of the key section of the a-th main girder of small and medium-sized bridges; Representing a time series matrix The i-th time point Theoretical displacement calculation value of the key section of the a-th main beam of a small and medium-sized bridge.

[0090] By installing displacement sensors at key sections in the mid-span of small and medium-sized bridges, the sampling frequency of the measured displacement is set to the time step for analyzing the theoretical displacement value. The mid-span section of the bridge is obtained. Measured displacement values ​​of the bridge under actual vehicle distribution at any time Through the formula: The relationship between the measured displacement and the theoretical displacement at mid-span of the first beam is as follows: Figure 15 As shown.

[0091] when When, it represents the time series matrix. The i-th time point The measured displacement value of the key section of the a-th main beam of the small and medium-sized bridge is less than the theoretical calculation value, the structural condition is diagnosed as safe, and the structural stiffness has a certain degree of redundancy.

[0092] when When, it represents the time series matrix. The i-th time point The measured displacement value of the critical section of the a-th main girder of the small-to-medium bridge is greater than or equal to the theoretically calculated value, and the structural condition is diagnosed as unsafe. An alarm message is issued, and further judgment is made based on the safety status of other sections. Figure 15 The time history curve of the safety status evaluation coefficient for the first main beam.

[0093] As shown in the figure above, the bridge safety condition evaluation coefficient for the mid-span section displacement under the actual vehicle distribution at any given time is always less than 1, indicating that the bridge structure is in a safe state and has a certain degree of redundancy. Therefore, this method can be used to quickly and accurately assess the safety condition of key bridge sections.

[0094] Example 2: like Figure 17 As shown, based on the same inventive concept as Embodiment 1, this embodiment provides a safety diagnosis system for small and medium-sized bridges based on spatial discrete axle load and displacement monitoring data. The method described includes: The axle load spatiotemporal distribution matrix establishment module is used to collect discrete vehicle weight data monitored by the weighing system on the bridge and establish the axle load spatiotemporal distribution matrix of the vehicle on the bridge. The displacement theory value influence matrix establishment module is used to calculate the theoretical displacement value of key sections at the mid-span of small and medium-span bridges under unit moving load and to establish the displacement theory value influence matrix under unit moving load. The theoretical displacement calculation module is used to calculate the theoretical displacement of key sections of the main beam of small and medium-sized bridges under real-time vehicle action based on the axle load spatiotemporal distribution matrix and the displacement theoretical value influence matrix. The measured displacement acquisition module is used to collect the measured displacement values ​​of key sections at the mid-span of small and medium-sized bridges in real time. The safety diagnosis module is used to calculate displacement-based safety status evaluation indicators for small and medium-sized bridges based on theoretical displacement calculations and measured displacement values, and to diagnose the safety status of small and medium-sized bridges.

[0095] In this embodiment, the measured displacement acquisition module includes a data sensing unit, a data transmission unit, and a main control unit connected in sequence. The data sensing unit comprises an infrared target and a video displacement meter. The infrared target serves as the optical recognition reference point for the video displacement meter, ensuring stable positioning in complex environments. It requires no power supply and relies on infrared reflection characteristics to enhance the reliability of low-light / nighttime recognition. The video displacement meter uses machine vision technology to capture real-time displacement changes on the structural surface, achieving non-contact, high-precision measurement.

[0096] The data transmission unit includes fiber optic transceivers and optical switches. Optical switches and fiber optic transceivers can convert between electrical and optical signals. Fiber optic transceivers are suitable for photoelectric signal conversion of a single device, while optical switches are suitable for multi-source electrical signal to optical signal conversion connections.

[0097] The main control unit includes a video data acquisition unit, a hard disk recorder (HDD), and a UPS power supply. The video data acquisition unit (industrial control computer) is used to acquire data from the video displacement gauges and process the data to convert it into structural displacement values. The UPS power supply provides power to the system in case of power failure. The HDD is used to store and manage video data.

[0098] Example 3: Based on the same inventive concept as Embodiment 1, this embodiment provides an electronic device, including a memory and a processor. The memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to execute the aforementioned method for safety diagnosis of small and medium-sized bridges based on spatial discrete axle load and displacement monitoring data.

[0099] Those skilled in the art will recognize that the modules of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components of the examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of the invention.

[0100] In the embodiments provided by this invention, it should be understood that the division of modules is only a logical functional division. In actual implementation, there may be other division methods, such as multiple modules can be combined into one module, one module can be split into multiple modules, or some features can be ignored.

[0101] Furthermore, the functional modules in the various embodiments of the present invention can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0102] If the integrated module is implemented as a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A safety diagnosis method for small and medium-sized bridges based on spatial discrete axle load and displacement monitoring data, characterized in that, Includes the following steps: Step S1: Collect discrete vehicle weight data monitored by the weighing system on the bridge and establish a spatiotemporal distribution matrix of vehicle axle load on the bridge. Step S2: Calculate the theoretical displacement values ​​of key sections at mid-span of small- and medium-span bridges under unit moving load, and establish the influence matrix of theoretical displacement values ​​under unit moving load. Step S3: Calculate the theoretical displacement of key sections of the main beam of small and medium-sized bridges under real-time vehicle action based on the axle load spatiotemporal distribution matrix and the displacement theoretical value influence matrix. Step S4: Real-time acquisition of measured displacement values ​​at key cross-sections at mid-span of small and medium-sized bridges; Step S5: Calculate the safety status evaluation index of small and medium-sized bridges based on theoretical displacement calculation values ​​and measured displacement values, and diagnose the safety status of small and medium-sized bridges.

2. The method for safety diagnosis of small and medium-sized bridges based on spatial discrete axle load and displacement monitoring data according to claim 1, characterized in that, Step S1, which involves collecting discrete vehicle weight data monitored by the weighing system on the bridge and establishing the spatiotemporal distribution matrix of vehicle axle load on the bridge, specifically includes the following steps: Step S11, set the start time as Analysis time is The analysis time step is Number of time periods divided Establish analysis duration Corresponding time series matrix ; Step S12, in the established time series matrix The middle determines the first The time when the car appeared on the bridge was obtained. Time series matrix of vehicles appearing on the bridge ; Step S13, let the length of the bridge be... The starting point of the bridge is 0, and the ending point of the bridge is... The bridge has N lanes. Calculate the first lane number for each lane. After the vehicle enters the bridge, the first axle in the time series matrix The i-th time point Location on the bridge ; Step S14, according to the first After the vehicle enters the bridge, the first axle in the time series matrix The i-th time point Location on the bridge Calculate the first The remaining axles of the vehicle at time point i Location on the bridge surface; Step S15: Divide the small and medium-sized bridges along their length into... Each region is divided into several areas, and the length of each area is... = 1 / 450~ 1 / 250; Step S16: For a bridge with n lanes, transfer the first lane number of each lane to the first lane. Each axle of the vehicle at time point i The location of the bridge deck and the division The location ranges of each region are matched to obtain the time series matrix. The i-th time point Down The axis redistribution data for each region is used to obtain the time series matrix. The i-th time point Spatiotemporal distribution matrix of axle load of vehicles on bridge The details are as follows: ； In the formula, This represents the spatiotemporal distribution matrix of axle load when a vehicle is traveling in the nth lane at the i-th time point; ； in, Let represent the total axle load of vehicles in the k-th region when the vehicle is traveling in the n-th lane at time i, where n = 1, ..., N.

3. The method for safety diagnosis of small and medium-sized bridges based on spatial discrete axle load and displacement monitoring data according to claim 2, characterized in that, In step S12, the established time series matrix The middle determines the first The exact time when the vehicle appeared on the bridge is as follows: ； in, This refers to the distance between the dynamic weighing system and the starting point of the bridge. For the first The speed of the vehicle, For the first The time it takes for a vehicle to pass through the dynamic weighing system. For the first The length of the vehicle; Find(*) is the Find function in MATLAB.

4. The method for safety diagnosis of small and medium-sized bridges based on spatial discrete axle load and displacement monitoring data according to claim 2, characterized in that, In step S13, the calculation of each lane's first... After the vehicle enters the bridge, in the time series matrix The i-th time point Location on the bridge Specifically as follows: No. After the vehicle enters the bridge from the starting point along the lane direction, the first The first axle of the vehicle after it enters the bridge is in the time series matrix. The i-th time point Location on the bridge The calculation method is as follows: ； No. After the vehicle enters the bridge from the end of the bridge along the lane direction, the first The first axle of the vehicle after it enters the bridge is in the time series matrix. The i-th time point Location on the bridge The calculation method is as follows: 。 5. The method for safety diagnosis of small and medium-sized bridges based on spatial discrete axle load and displacement monitoring data according to claim 2, characterized in that, In step S14, according to the first The first axle of the vehicle after it enters the bridge is in the time series matrix. The i-th time point Location on the bridge Calculate the first The remaining axles of the vehicle at time point i The specific location on the bridge surface is as follows: Let the first The car has B axles, the first... The distance between the first axle and the b-th axle of the vehicle is ,but: No. When a vehicle enters the bridge from the starting point along the lane direction, the position of the b-th axle is... ; No. When a vehicle enters the bridge from the end of the bridge along the lane direction, the position of the b-th axle is... , where b=2,···,B.

6. The method for safety diagnosis of small and medium-sized bridges based on spatial discrete axle load and displacement monitoring data according to claim 2, characterized in that, Step S2 specifically includes the following steps: Step S21: Establish the bridge finite element model using the beam grid method, and follow... 1 / 450~ Divide the unit into units of 1 / 250 of its length; Step S22: Calculate the displacement response of the key section of the small bridge under unit load movement. Divide the bridge into actual lanes and apply a unit concentrated load according to the actual lane conditions. Establish the load case of the unit concentrated load moving back and forth on the lanes. Calculate the theoretical displacement value of the key section of the a-th main beam when it reaches the k-th region during the unit concentrated load movement process. ; Step S23: Establish the theoretical displacement matrix of the key section of the main beam when the unit moving load of the a-th main beam is applied to the n-th lane. The details are as follows: ； Where T represents transpose.

7. The method for safety diagnosis of small and medium-sized bridges based on spatial discrete axle load and displacement monitoring data according to claim 1, characterized in that, In step S3, the theoretical displacement calculation values ​​of key sections of the main beam of small and medium-sized bridges under the real-time action of actual vehicles are calculated based on the axle load spatiotemporal distribution matrix and the displacement theoretical value influence matrix as follows: Time series matrix The i-th time point Theoretical displacement calculation value of the key section of the a-th main beam of small and medium-sized bridge The calculation method is as follows: ； Where N is the number of lanes the bridge is divided into according to the actual number of lanes.

8. The method for safety diagnosis of small and medium-sized bridges based on spatial discrete axle load and displacement monitoring data according to claim 1, characterized in that, Step S5, which involves calculating the safety status evaluation index of small and medium-sized bridges based on theoretical displacement calculations and measured displacement values, and diagnosing the safety status of these bridges, specifically includes the following steps: The safety status evaluation index for small and medium-sized bridges based on displacement is calculated as follows: ； in, Representing a time series matrix The i-th time point Safety evaluation indicators for the critical section of the a-th main girder of small and medium-sized bridges; Representing a time series matrix The i-th time point Measured displacement value of the key section of the a-th main beam of a small and medium-sized bridge; Representing a time series matrix The i-th time point Theoretical displacement calculation value of the key section of the a-th main beam of a small and medium-sized bridge; when When, it represents the time series matrix. The i-th time point The measured displacement value of the critical section of the a-th main beam of the small and medium-sized bridge is less than the theoretical calculation value, and the structural condition is diagnosed as safe. when When, it represents the time series matrix. The i-th time point The measured displacement value of the critical section of the a-th main beam of the small and medium-sized bridge is greater than or equal to the theoretical calculation value, and the structural condition is diagnosed as unsafe.

9. A safety diagnosis system for small and medium-sized bridges based on spatial discrete axle load and displacement monitoring data, characterized in that, The method described by any one of claims 1 to 8 includes: The axle load spatiotemporal distribution matrix establishment module is used to collect discrete vehicle weight data monitored by the weighing system on the bridge and establish the axle load spatiotemporal distribution matrix of the vehicle on the bridge. The displacement theory value influence matrix establishment module is used to calculate the theoretical displacement value of key sections at the mid-span of small and medium-span bridges under unit moving load and to establish the displacement theory value influence matrix under unit moving load. The theoretical displacement calculation module is used to calculate the theoretical displacement of key sections of the main beam of small and medium-sized bridges under real-time vehicle action based on the axle load spatiotemporal distribution matrix and the displacement theoretical value influence matrix. The measured displacement acquisition module is used to collect the measured displacement values ​​of key sections at the mid-span of small and medium-sized bridges in real time. The safety diagnosis module is used to calculate displacement-based safety status evaluation indicators for small and medium-sized bridges based on theoretical displacement calculations and measured displacement values, and to diagnose the safety status of small and medium-sized bridges.

10. An electronic device, characterized in that, The device includes a memory and a processor, wherein the memory stores a computer program and the processor runs the computer program to enable the electronic device to perform a safety diagnosis method for small and medium-sized bridges based on spatial discrete axle load and displacement monitoring data as described in any one of claims 1 to 8.

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