Method and system for evaluating bearing capacity of bridge structure load test

Abstract

The present application relates to a kind of bridge structure load test method and system for evaluating bearing capacity, belong to bridge safety detection and evaluation technical field, solve the problem that current load test needs to close traffic or slow driving to cause high cost and difficult to realize.The present application includes determining each test measuring point of the bridge to be evaluated, collecting the dynamic strain measured data or dynamic deflection measured data of large transport vehicle at each test measuring point at each time;After filtering noise, corresponding dynamic strain baseline data or dynamic deflection baseline data is obtained;According to dynamic strain measured data or dynamic deflection measured data, and corresponding dynamic strain baseline data or dynamic deflection baseline data, the quasi-static strain or deflection measured value of each test measuring point is obtained;Based on the finite element mechanics model of the bridge to be evaluated, the strain or deflection calculation value of each test measuring point is calculated, and according to the quasi-static strain or deflection measured value of each test measuring point, the calibration coefficient of each test measuring point is calculated to evaluate bearing capacity.The present application realizes the real-time evaluation of bridge bearing capacity.

Description

Technical Field

[0001] This invention relates to the field of bridge safety inspection and assessment technology, and in particular to a method and system for evaluating the load-bearing capacity of bridge structures through load testing. Background Technology

[0002] The traditional (static load) test method for bridges is a direct method for evaluating the bridge's load-bearing capacity. It is based on the requirements of the Highway Bridge Load Test Code (JTG / TJ21-01-2015). Under closed traffic conditions, an equivalent static external load (usually a loaded vehicle) is applied to the bridge structure. The test is conducted using testing instruments and equipment to record the structural response of the bridge under the load. This method can provide a scientific basis and support for future maintenance, repair, and reinforcement decisions.

[0003] The traditional (static load) test method for bridges is the most accurate and meets national standards, but it has the problems of requiring traffic closure and high cost. Most operating highways cannot accept traffic closures, firstly because of traffic flow requirements, and secondly because it would affect toll revenue.

[0004] The quasi-static load test method is a rapid assessment method for bridge structural condition based on influence line comparison analysis and model calibration technology. Generally, it begins with one or two heavy-duty vehicles slowly driving along designated lanes on the bridge deck. Using a synchronous data acquisition system, the strain time history curves of various measuring points on the structure are recorded in real time. The correspondence between the vehicle's movement on the bridge deck and the strain at the measuring points is then marked using a manual or automatic distance measurement system. The stress influence lines at each control measuring point of the bridge are then calculated using the measured data. Based on these stress influence lines, the finite element analysis model of the structure is calibrated, thereby achieving the purpose of detecting structural damage and assessing the structural condition.

[0005] Quasi-static load testing methods can replace traditional load testing to some extent, but they have problems such as the need for heavy-duty vehicles of 20-30t to travel slowly (generally about 5km / h), which is difficult to achieve on high speeds, and the difficulty in ensuring the accuracy of structural model correction. Summary of the Invention

[0006] Based on the above analysis, the embodiments of the present invention aim to provide a method and system for evaluating the bearing capacity of bridge structures by load testing, in order to solve the problems of high cost and difficulty in implementation caused by the need for existing load testing to close traffic or slow down traffic.

[0007] On one hand, embodiments of the present invention provide a method for evaluating the bearing capacity of a bridge structure under load testing, comprising the following steps:

[0008] Determine the test points of the bridge to be evaluated, and collect the dynamic strain or dynamic deflection data of the heavy transport vehicle at each test point of the bridge to be evaluated at each time.

[0009] Based on the morphological filtering algorithm, noise in the measured dynamic strain or dynamic deflection data at each test point at each time is filtered out to obtain the corresponding dynamic strain baseline data or dynamic deflection baseline data; based on the measured dynamic strain or dynamic deflection data at each test point at each time, and the corresponding dynamic strain baseline data or dynamic deflection baseline data, the quasi-static strain or deflection measured values ​​of each test point are obtained.

[0010] Based on the finite element mechanical model of the bridge to be evaluated, the strain or deflection of the bridge model at each test point is calculated according to the total load effect value of the heavy transport vehicle passing through the bridge to be evaluated.

[0011] Based on the measured values ​​of quasi-static strain or deflection at each test point, and the calculated values ​​of strain or deflection, the verification coefficient for each test point is calculated, and the bearing capacity is evaluated based on the verification coefficient.

[0012] Based on further improvements to the above method, the test measurement points for the bridge to be evaluated are determined, including:

[0013] The most unfavorable cross section is calculated based on the structural data of the bridge to be evaluated.

[0014] Dynamic strain sensors and dynamic deflection sensors are installed at the bottom of each box girder corresponding to the most unfavorable cross section. They are used as multiple first-type test measurement points to collect dynamic strain measurement data of bending strain at the most unfavorable cross section, and as multiple second-type test measurement points to collect dynamic deflection measurement data of bending deflection at the most unfavorable cross section.

[0015] Multiple dynamic strain sensors were installed on the web of the box girder at the emergency lane location corresponding to the most unfavorable section, and the dynamic strain measurement data of the neutral axis height of the most unfavorable section were collected as multiple third-type test measurement points.

[0016] Based on a further improvement to the above method, the method also includes: obtaining the neutral axis height error through the following steps:

[0017] Based on the measured quasi-static strain value and distance from the bottom plate of the box girder at each third type of test point, a linear model of the strain of the side beam is fitted.

[0018] Based on the linear model of the edge beam strain, the distance from the bottom plate of the box girder is taken when the measured static strain value is 0, and used as the measured neutral axis height of the third type of test point;

[0019] Based on the data of the box girder section, the distance from the bottom of the box girder to the neutral axis is calculated, which is used as the theoretical neutral axis height of the third type of test measuring point;

[0020] The neutral axis height error is obtained based on the measured neutral axis height and the theoretical neutral axis height at the third type of test points.

[0021] Based on further improvements to the above method, when collecting dynamic strain or dynamic deflection data of heavy transport vehicles at various test points on the bridge to be evaluated at various times, it is not necessary to close the traffic. The heavy transport vehicles pass through the bridge to be evaluated at a speed that meets the high-speed safety requirements. Furthermore, the ratio of the total load effect value at each test point to the design load effect value of the most unfavorable section of the bridge to be evaluated is within the range of static test load efficiency [0.95, 1.05].

[0022] Based on further improvements to the above method, noise in the measured dynamic strain or dynamic deflection data at each test point at each time point is filtered out using a morphological filtering algorithm to obtain the corresponding dynamic strain baseline data or dynamic deflection baseline data, including:

[0023] For each experimental measurement point and each moment, the measured dynamic strain or dynamic deflection data are processed using the following formula to successively remove high-frequency noise and low-frequency noise, thus obtaining the corresponding dynamic strain baseline data or dynamic deflection baseline data:

[0024]

[0025]

[0026] in, This indicates the expansion operation. The erosion operation is represented by S1, which represents the width of the linear structuring element used to filter high-frequency noise, and S2, which represents the width of the linear structuring element used to filter low-frequency noise; F0(x kt F1(x) represents the measured dynamic strain or dynamic deflection data at test point k at time t. kt F2(x) represents the measured dynamic strain or dynamic deflection data at test point k at time t after removing high-frequency noise. kt ) represents the baseline data of dynamic strain or dynamic deflection at test point k at time t.

[0027] Based on further improvements to the above method, the quasi-static strain or deflection measured values ​​for each test point are obtained according to the measured dynamic strain or deflection data at each time point, and the corresponding dynamic strain baseline data or dynamic deflection baseline data, including:

[0028] For each test point, the measured dynamic strain or dynamic deflection data at each time point is subtracted from the corresponding dynamic strain baseline data or dynamic deflection baseline data, and the maximum difference is taken as the quasi-static strain or deflection measured value of each test point.

[0029] Based on further improvements to the above method, the strain or deflection values ​​of the bridge model to be evaluated at each test measurement point are calculated using the following formula:

[0030] ε k =S k ·H S / EI z

[0031] y k =S k / B

[0032] Where, ε k S represents the calculated strain value at test measurement point k. k H represents the total load effect value at test point k when a heavy transport vehicle passes over the bridge to be evaluated. S The theoretical neutral axis height is represented by E, and the elastic modulus is represented by I. z Represents the moment of inertia of the main beam; y k B represents the calculated deflection value at test point k, and B represents the overall stiffness of the main beam.

[0033] Based on further improvements to the above method, the load-bearing capacity is assessed, including:

[0034] When the verification coefficients of the first and second types of test points are both less than or equal to 1, and the neutral axis height error of the third type of test point is within the preset range, the bearing capacity of the bridge to be evaluated meets the design requirements; otherwise, the bearing capacity of the bridge to be evaluated does not meet the design requirements.

[0035] On the other hand, embodiments of the present invention provide a system for evaluating the load-bearing capacity of bridge structures through load testing, comprising:

[0036] The data acquisition module is used to determine each test measurement point of the bridge to be evaluated and to collect the measured dynamic strain or dynamic deflection data of the heavy transport vehicle at each test measurement point of the bridge to be evaluated at each time.

[0037] The quasi-static measured value acquisition module is used to filter noise in the dynamic strain or dynamic deflection measured data at each test point at each time step according to the morphological filtering algorithm, and obtain the corresponding dynamic strain baseline data or dynamic deflection baseline data; based on the dynamic strain or dynamic deflection measured data at each test point at each time step, and the corresponding dynamic strain baseline data or dynamic deflection baseline data, the quasi-static strain or deflection measured values ​​of each test point are obtained.

[0038] The theoretical calculation value acquisition module is used to calculate the strain or deflection of the bridge model at each test point based on the finite element mechanical model of the bridge to be evaluated and the total load effect value of each test point of the heavy transport vehicle passing through the bridge to be evaluated.

[0039] The load-bearing capacity assessment module is used to calculate the verification coefficient of each test point based on the measured quasi-static strain or deflection values ​​and the calculated strain or deflection values, and to assess the load-bearing capacity based on the verification coefficients.

[0040] Based on further improvements to the above system, the system also includes:

[0041] The neutral axis height error acquisition module is used to fit a linear model of the edge beam strain based on the measured quasi-static strain values ​​of test points set on the web of the box girder and the distance from the bottom plate of the box girder; based on the linear model of the edge beam strain, the distance from the bottom plate of the box girder obtained when the measured quasi-static strain value is 0 is taken as the measured neutral axis height; based on the data of the box girder section, the distance from the bottom of the box girder to the neutral axis is calculated as the theoretical neutral axis height; and the neutral axis height error is obtained based on the measured neutral axis height and the theoretical neutral axis height.

[0042] The load-bearing capacity assessment module is also used to assess the load-bearing capacity based on the verification coefficients of each test point and the neutral axis height error.

[0043] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: by selecting heavy transport vehicles (generally referring to oversized vehicles with a total weight of about 100 to 200 tons) as the external test load, deploying a small number of sensors at key measuring points, collecting real-time measured response data, and conducting tests according to the principle of meeting load efficiency, the bridge bearing capacity can be automatically evaluated without closing traffic or slowing down the vehicle. The invention is low in cost and easy to implement and promote.

[0044] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0045] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0046] Figure 1 This is a flowchart of a method for evaluating the bearing capacity of a bridge structure by load testing according to Embodiment 1 of the present invention;

[0047] Figure 2 This is a schematic diagram of the most unfavorable cross-section of the bridge to be evaluated in Embodiment 1 of the present invention;

[0048] Figure 3 This is a schematic diagram showing the layout of each test point in Embodiment 1 of the present invention. Detailed Implementation

[0049] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0050] Example 1

[0051] A specific embodiment of the present invention discloses a method for evaluating the bearing capacity of a bridge structure through load testing, such as... Figure 1 As shown, it includes the following steps:

[0052] S1: Determine the test points of the bridge to be evaluated, and collect the dynamic strain or dynamic deflection data of the heavy transport vehicle at each test point of the bridge to be evaluated at each time.

[0053] It should be noted that the test points for the bridge to be evaluated include:

[0054] The most unfavorable cross section is calculated based on the structural data of the bridge to be evaluated.

[0055] Dynamic strain sensors and dynamic deflection sensors are installed at the bottom of each box girder corresponding to the most unfavorable cross section. They are used as multiple first-type test measurement points to collect dynamic strain measurement data of bending strain at the most unfavorable cross section, and as multiple second-type test measurement points to collect dynamic deflection measurement data of bending deflection at the most unfavorable cross section.

[0056] Multiple dynamic strain sensors were installed on the web of the box girder at the emergency lane location corresponding to the most unfavorable section, and the dynamic strain measurement data of the neutral axis height of the most unfavorable section were collected as multiple third-type test measurement points.

[0057] It should be noted that the number of the first and second types of test points is the same as the number of box girders of the bridge to be evaluated; the number of the third type of test points is generally selected as 3 to 4, and the total height obtained based on the interval height and number of test points does not exceed 80% of the height of the box girder.

[0058] For example, for a prefabricated continuous small box girder bridge, the mid-span section of the side span is selected as the most unfavorable section. Figure 2 It is a 3-span precast prestressed concrete continuous small box girder bridge. The most unfavorable section is section AA, and the cross-section of this section is as follows: Figure 3 As shown. In Figure 3 In the middle, dynamic strain sensors are set up at A1' to A4', which are four first-class test measurement points; dynamic deflection sensors are set up at A1 to A4, which are four second-class test measurement points; dynamic strain sensors are also set up at A5' to A8', which are four third-class test measurement points. The interval height is 25 meters, the total height is 100 meters, which does not exceed 80% of the beam height of 150.

[0059] It should be noted that in this embodiment, the above three types of test points are uniformly represented by test point k in the formula. Based on the dynamic strain sensor or dynamic deflection sensor set up at each test point, the corresponding dynamic strain measurement data or dynamic deflection measurement data are collected.

[0060] It is worth noting that in this embodiment, the ratio of the total load effect value of the oversized transport vehicle passing through each test measurement point of the bridge to be evaluated to the design load effect value of the most unfavorable section of the bridge to be evaluated is within the range of static test load efficiency [0.95, 1.05], that is, oversized vehicles with a total weight of about 100 to 200 tons are selected as the additional test load.

[0061] Specifically, from the vehicle information of vehicles permitted to pass over bridges awaiting evaluation, the total number of axles and the load on each axle of major haul transport vehicles are obtained. The total load effect value of each major haul transport vehicle at each test point is calculated using the following formula:

[0062]

[0063] Among them, S k Let represent the total load effect value of the test measuring point k when the oversized transport vehicle passes over the bridge to be evaluated, M represent the total number of axles of the oversized transport vehicle, and i represent the i-th axle of the oversized transport vehicle, 1≤i≤M; p i Let y represent the load of the i-th axle. ki The ordinate value represents the influence surface of the internal force of the main beam of the bridge corresponding to the i-th axle at the test measurement point k.

[0064] One qualified heavy-duty transport vehicle is randomly selected as the load test vehicle. Traffic closure is not required. The heavy-duty transport vehicle passes over the bridge to be evaluated at a speed meeting high-speed safety requirements. Real-time monitoring is conducted using radar and video surveillance equipment to obtain the vehicle's planar coordinates and speed v. Based on a preset time period Δt (exemplarily Δt = 300 seconds), when the heavy-duty transport vehicle reaches a distance v × Δt from the most unfavorable cross-section of the bridge to be evaluated, dynamic strain and deflection sensors at each test point begin collecting data until the heavy-duty transport vehicle exceeds the distance v × Δt from the most unfavorable cross-section of the bridge to be evaluated. That is, according to the sampling frequency, the measured dynamic strain and deflection data are recorded and stored at each moment within the time range [h-Δt, h+Δt], where moment h represents the moment when the heaviest axle of the heavy-duty transport vehicle is loaded at the most unfavorable cross-section.

[0065] The measured dynamic strain and dynamic deflection data collected at each time point k are represented as the measured dynamic strain sequence data F0(x) kε )={x kε1 ,x kε2 ,…,xkεt ,…,x kεm}, Dynamic deflection measured sequence data F0(x ky )={x ky1 ,x ky2 ,…,x kyt ,…,x kyn}; where m and n represent the number of dynamic strain and dynamic deflection samples collected, respectively, and m = 2Δtf ε n=2Δtf y f ε f represents the dynamic strain sampling frequency. y This indicates the dynamic deflection sampling frequency. For example, both the dynamic strain sampling frequency and the dynamic deflection sampling frequency are 10Hz.

[0066] Compared with existing technologies, this embodiment deploys sensors at a small number of key measuring points, selects oversized transport vehicles, and collects real-time measured response data under conditions where traffic is not closed and the oversized transport vehicles are driving normally, thereby improving the accuracy of the test.

[0067] S2: Based on the morphological filtering algorithm, filter the noise in the measured dynamic strain or dynamic deflection data at each test point at each time to obtain the corresponding dynamic strain baseline data or dynamic deflection baseline data; based on the measured dynamic strain or dynamic deflection data at each test point at each time, and the corresponding dynamic strain baseline data or dynamic deflection baseline data, obtain the quasi-static strain or deflection measured values ​​at each test point.

[0068] It should be noted that, in order to effectively remove the influence of non-vehicle load factors and noise, this embodiment uses a filtering algorithm based on mathematical morphology to sequentially remove high-frequency noise and low-frequency noise from the measured dynamic strain or dynamic deflection data at each test point at each time point according to the following formula, thereby obtaining the corresponding dynamic strain baseline data or dynamic deflection baseline data:

[0069]

[0070]

[0071] in, This represents the expansion operation. The erosion operation is represented by S1, which represents the width of the linear structuring element used to filter high-frequency noise, and S2, which represents the width of the linear structuring element used to filter low-frequency noise; F0(x kt F1(x) represents the measured dynamic strain or dynamic deflection data at test point k at time t. kt F2(x) represents the measured dynamic strain or dynamic deflection data at test point k at time t after removing high-frequency noise. kt) represents the baseline data of dynamic strain or dynamic deflection at test point k at time t.

[0072] Specifically, when filtering the measured dynamic strain data at each test point at each time step, S1 and S2 are calculated using the following formulas:

[0073] S1=S ε1 =T b1 ×f ε Formula (4)

[0074] S2 = S ε2 =T b2 ×f ε Formula (5)

[0075] Among them, T b1 T represents the time width of the characteristic waveform of high-frequency noise. b2 The time width representing the characteristic waveform of low-frequency noise, exemplarily, is T. b1 T is 0.05. b2 It is 0.025.

[0076] At this time, F0(x) kt F0(x) represents the measured dynamic strain data at test point k at time t. kεt ), F1(x kt F1(x) represents the measured dynamic strain data at test point k at time t after removing high-frequency noise. kεt ), F2(x kt F2(x) represents the baseline dynamic strain data of test point k at time t. kεt ).

[0077] When filtering the measured dynamic deflection data at each test point at each time, S1 and S2 are calculated using the following formulas:

[0078] S1=S y1 =T b1 ×f y Formula (6)

[0079] S2 = S y2 =T b2 ×f y Formula (7)

[0080] At this time, F0(x) kt F0(x) represents the measured dynamic deflection data of test point k at time t. kyt ), F1(x kt F1(x) represents the measured dynamic deflection data of test point k at time t after removing high-frequency noise. kyt ), F2(x tF2(x) represents the baseline data of dynamic deflection at test point k at time t. kyt ).

[0081] Furthermore, based on the measured dynamic strain or deflection data at each test point at each time step, and the corresponding dynamic strain or deflection baseline data, the quasi-static strain or deflection measured values ​​for each test point are obtained. This includes: for each test point, subtracting the corresponding dynamic strain or deflection baseline data from the measured dynamic strain or deflection data at each time step, and taking the maximum difference as the quasi-static strain or deflection measured value for each test point. This yields the quasi-static response value generated when the heavy transport vehicle passes through the most unfavorable section of the bridge. The calculation formula is as follows:

[0082] ε ks =MAX(F0(x) kεr )-F2(x kεr ),r=1,2,3,…,m; Formula (8)

[0083] y ks =MAX(F0(x) kyu )-F2(x kyu ),u=1,2,3,…,n; Formula (9)

[0084] Where, ε ks y represents the measured quasi-static strain at test point k. ks This represents the measured quasi-static deflection value at test point k; MAX(·) indicates taking the maximum value; F0(x kεr F2(x) represents the measured dynamic strain data of test point k at time r. kεr ) indicates that the experimental measuring point k at time r is related to F0(x) kεr The corresponding dynamic strain baseline data; F0(x) kyu F2(x) represents the measured dynamic deflection data of test point k at time u. kyu ) indicates that the experimental measuring point k at time u is related to F0(x) kyu The corresponding dynamic strain baseline data.

[0085] S3: Based on the finite element mechanical model of the bridge to be evaluated, the strain and deflection values ​​of the bridge model at each test point are calculated according to the total load effect value of the heavy transport vehicle passing through the bridge to be evaluated.

[0086] It should be noted that the strain values ​​of the bridge model to be evaluated at each test measurement point are calculated using the following formula:

[0087] ε k =S k ·H S / EI zFormula (10)

[0088] Where, ε k S represents the calculated strain value at test measurement point k. k H represents the total load effect value at test point k when a heavy transport vehicle passes over the bridge to be evaluated. S The theoretical neutral axis height is represented by E, and the elastic modulus is represented by I. z This represents the moment of inertia of the main beam.

[0089] It should be noted that the theoretical neutral axis height H S The box girder section is divided into multiple component sections, and the result is calculated using the following formula:

[0090]

[0091] Among them, A j H is the area of ​​the j-th component section of the box girder cross section. j Let A be the distance from the centroid of the j-th component section to the bottom of the box girder. j This represents the total area of ​​the box girder's cross-section.

[0092] The deflection values ​​of the bridge model to be evaluated at each test point are calculated using the following formula:

[0093] y k =S k / B Formula (12)

[0094] Among them, y k S represents the calculated deflection value at test point k. k B represents the total load effect value of the test measuring point k when the heavy transport vehicle passes through the bridge to be evaluated, and B represents the overall stiffness of the main beam.

[0095] S4: Based on the measured values ​​of quasi-static strain or deflection at each test point, and the calculated values ​​of strain or deflection, calculate the verification coefficient for each test point, and evaluate the bearing capacity based on the verification coefficient.

[0096] It should be noted that the verification coefficients include the ratio of the measured value of quasi-static strain to the calculated value of strain, and the ratio of the measured value of quasi-static deflection to the calculated value of deflection.

[0097] Specifically, in this embodiment, the measured quasi-static strain ε is calculated for the first type of test measurement points. ks With the calculated strain value ε k The ratio is used to obtain the verification coefficient, and the measured quasi-static deflection y is calculated for the second type of test points. ks With the calculated deflection value y kThe ratio of the two test points is used to obtain the verification coefficient. When the verification coefficients of the first type of test points and the second type of test points are both less than or equal to 1, the bearing capacity of the bridge to be evaluated meets the design requirements.

[0098] Furthermore, the neutral axis height error is obtained for the third type of test points, including the following steps:

[0099] Based on the measured quasi-static strain value and the distance from the bottom plate of the box girder at each third-type test point, a linear model of the strain of the side beam is fitted; that is, the measured quasi-static strain value at each third-type test point is used as the x-value, and the distance from the bottom plate of the box girder at each third-type test point is used as the y-value for linear fitting.

[0100] Based on the linear model of the edge beam strain, the distance from the bottom plate of the box girder is taken when the measured static strain value is 0, and used as the measured neutral axis height of the third type of test point;

[0101] Based on the data of the box girder section, the distance from the bottom of the box girder to the neutral axis is calculated, which is used as the theoretical neutral axis height of the third type of test measuring point;

[0102] The neutral axis height error is obtained based on the measured neutral axis height and the theoretical neutral axis height at the third type of test points.

[0103] When the verification coefficients of the first and second types of test points are both less than or equal to 1, and the neutral axis height error of the third type of test point is within a preset range, the bearing capacity of the bridge to be evaluated meets the design requirements. Preferably, the neutral axis height error is defined as within ±5%, where the ratio of the measured neutral axis height to the theoretical neutral axis height is within the range of [0.95, 1.05].

[0104] Compared with existing technologies, the method for evaluating the load-bearing capacity of bridge structures provided in this embodiment selects large transport vehicles (generally referring to oversized vehicles with a total weight of about 100 to 200 tons) as external test loads, deploys a small number of sensors at key measuring points, collects measured response data in real time, and conducts tests according to the principle of meeting load efficiency. It does not require closing traffic or slowing down the vehicle, automatically evaluates the load-bearing capacity of the bridge, and is low in cost and easy to implement and promote.

[0105] Example 2

[0106] Another embodiment of the present invention discloses a system for evaluating the load-bearing capacity of bridge structures through load testing, thereby implementing the method for evaluating the load-bearing capacity of bridge structures through load testing in Embodiment 1. The specific implementation of each module is described in the corresponding description in Embodiment 1. The system includes the following modules:

[0107] The data acquisition module is used to determine each test measurement point of the bridge to be evaluated and to collect the measured dynamic strain or dynamic deflection data of the heavy transport vehicle at each test measurement point of the bridge to be evaluated at each time.

[0108] The quasi-static measured value acquisition module is used to filter noise in the dynamic strain or dynamic deflection measured data at each test point at each time step according to the morphological filtering algorithm, and obtain the corresponding dynamic strain baseline data or dynamic deflection baseline data; based on the dynamic strain or dynamic deflection measured data at each test point at each time step, and the corresponding dynamic strain baseline data or dynamic deflection baseline data, the quasi-static strain or deflection measured values ​​of each test point are obtained.

[0109] The theoretical calculation value acquisition module is used to calculate the strain or deflection of the bridge model at each test point based on the finite element mechanical model of the bridge to be evaluated and the total load effect value of each test point of the heavy transport vehicle passing through the bridge to be evaluated.

[0110] The load-bearing capacity assessment module is used to calculate the verification coefficient of each test point based on the measured quasi-static strain or deflection values ​​and the calculated strain or deflection values, and to assess the load-bearing capacity based on the verification coefficients.

[0111] Furthermore, the system also includes:

[0112] The neutral axis height error acquisition module is used to fit a linear model of the edge beam strain based on the measured quasi-static strain values ​​of test points set on the web of the box girder and the distance from the bottom plate of the box girder; based on the linear model of the edge beam strain, the distance from the bottom plate of the box girder obtained when the measured quasi-static strain value is 0 is taken as the measured neutral axis height; based on the data of the box girder section, the distance from the bottom of the box girder to the neutral axis is calculated as the theoretical neutral axis height; the neutral axis height error is obtained based on the ratio of the measured neutral axis height to the theoretical neutral axis height.

[0113] The load-bearing capacity assessment module is also used to assess the load-bearing capacity based on the verification coefficients of each test point and the neutral axis height error.

[0114] Since the system for evaluating the bearing capacity of a bridge structure by load testing in this embodiment is related to the aforementioned method for evaluating the bearing capacity of a bridge structure by load testing, they can be mutually referenced. Therefore, this description is redundant and will not be repeated here. Because this system embodiment shares the same principle as the aforementioned method embodiment, it also possesses the corresponding technical effects of the aforementioned method embodiment.

[0115] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware, and the program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0116] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for evaluating the bearing capacity of a bridge structure by load testing, characterized in that, Includes the following steps: Determine the test points of the bridge to be evaluated, and collect the dynamic strain or dynamic deflection data of the heavy transport vehicle at each test point of the bridge to be evaluated at each time. Based on the morphological filtering algorithm, noise in the measured dynamic strain or dynamic deflection data at each test point at each time is filtered out to obtain the corresponding dynamic strain baseline data or dynamic deflection baseline data; based on the measured dynamic strain or dynamic deflection data at each test point at each time, and the corresponding dynamic strain baseline data or dynamic deflection baseline data, the quasi-static strain or deflection measured values ​​of each test point are obtained. Based on the finite element mechanical model of the bridge to be evaluated, the strain or deflection of the bridge model at each test point is calculated according to the total load effect value of the heavy transport vehicle passing through the bridge to be evaluated. Based on the measured values ​​of quasi-static strain or deflection at each test point, and the calculated values ​​of strain or deflection, the verification coefficient for each test point is calculated, and the bearing capacity is evaluated based on the verification coefficient.

2. The method for evaluating the bearing capacity of bridge structures by load testing according to claim 1, characterized in that, The determination of the test points for the bridge to be evaluated includes: The most unfavorable cross section is calculated based on the structural data of the bridge to be evaluated. Dynamic strain sensors and dynamic deflection sensors are installed at the bottom of each box girder corresponding to the most unfavorable cross section. They are used as multiple first-type test measurement points to collect dynamic strain measurement data of bending strain at the most unfavorable cross section, and as multiple second-type test measurement points to collect dynamic deflection measurement data of bending deflection at the most unfavorable cross section. Multiple dynamic strain sensors were installed on the web of the box girder at the emergency lane location corresponding to the most unfavorable section, and the dynamic strain measurement data of the neutral axis height of the most unfavorable section were collected as multiple third-type test measurement points.

3. The method for evaluating the bearing capacity of bridge structures by load testing according to claim 2, characterized in that, The method further includes: obtaining the neutral axis height error through the following steps: Based on the measured quasi-static strain value and distance from the bottom plate of the box girder at each third type of test point, a linear model of the strain of the side beam is fitted. Based on the linear model of the edge beam strain, the distance from the bottom plate of the box girder is taken when the measured static strain value is 0, and used as the measured neutral axis height of the third type of test point; Based on the data of the box girder section, the distance from the bottom of the box girder to the neutral axis is calculated, which is used as the theoretical neutral axis height of the third type of test measuring point; The neutral axis height error is obtained based on the measured neutral axis height and the theoretical neutral axis height at the third type of test points.

4. The method for evaluating the bearing capacity of bridge structures by load testing according to claim 2, characterized in that, When collecting dynamic strain or dynamic deflection data of the heavy transport vehicle at each test point on the bridge to be evaluated at each moment, it is not necessary to close the traffic. The heavy transport vehicle passes through the bridge to be evaluated at a speed that meets the high-speed safety requirements. Furthermore, the ratio of the total load effect value at each test point to the design load effect value of the most unfavorable section of the bridge to be evaluated is within the range of static test load efficiency [0.95, 1.05].

5. The method for evaluating the bearing capacity of bridge structures by load testing according to claim 2, characterized in that, The step of filtering noise from the measured dynamic strain or dynamic deflection data at each test point at each time point using a morphological filtering algorithm to obtain the corresponding dynamic strain baseline data or dynamic deflection baseline data includes: For each experimental measurement point and each moment, the measured dynamic strain or dynamic deflection data are processed using the following formula to successively remove high-frequency noise and low-frequency noise, thus obtaining the corresponding dynamic strain baseline data or dynamic deflection baseline data: ； ； in, This represents the expansion operation. This represents the erosion operation. This represents the width of a linear structural element used for filtering high-frequency noise. This represents the width of a linear structural element used for filtering low-frequency noise. This represents the measured dynamic strain or dynamic deflection data at test point k at time t. This represents the measured dynamic strain or dynamic deflection data at test point k at time t after removing high-frequency noise. This represents the baseline data of dynamic strain or dynamic deflection at test point k at time t.

6. The method for evaluating the bearing capacity of bridge structures by load testing according to claim 5, characterized in that, The process of obtaining the quasi-static strain or deflection measured values ​​for each test point based on the measured dynamic strain or deflection data at each time point, and the corresponding dynamic strain baseline data or dynamic deflection baseline data, includes: For each test point, the measured dynamic strain or dynamic deflection data at each time point is subtracted from the corresponding dynamic strain baseline data or dynamic deflection baseline data, and the maximum difference is taken as the quasi-static strain or deflection measured value of each test point.

7. The method for evaluating the bearing capacity of bridge structures by load testing according to claim 3, characterized in that, The strain or deflection values ​​of the bridge model to be evaluated at each test point are calculated using the following formula: ； ； in, This represents the calculated strain value at test point k. This represents the total load effect value at test point k when a heavy transport vehicle passes over the bridge to be evaluated. The height of the theoretical neutral axis is represented by E, and the elastic modulus is represented by E. Indicates the moment of inertia of the main beam; This represents the calculated deflection value at test point k. This indicates the overall stiffness of the main beam.

8. The method for evaluating the bearing capacity of bridge structures by load testing according to claim 3, characterized in that, The assessment of load-bearing capacity includes: When the verification coefficients of the first and second types of test points are both less than or equal to 1, and the neutral axis height error of the third type of test point is within the preset range, the bearing capacity of the bridge to be evaluated meets the design requirements; otherwise, the bearing capacity of the bridge to be evaluated does not meet the design requirements.

9. A system for evaluating the load-bearing capacity of bridge structures through load testing, characterized in that, include: The data acquisition module is used to determine each test measurement point of the bridge to be evaluated and to collect the measured dynamic strain or dynamic deflection data of the heavy transport vehicle at each test measurement point of the bridge to be evaluated at each time. The quasi-static measured value acquisition module is used to filter noise in the dynamic strain or dynamic deflection measured data at each test point at each time step according to the morphological filtering algorithm, and obtain the corresponding dynamic strain baseline data or dynamic deflection baseline data; based on the dynamic strain or dynamic deflection measured data at each test point at each time step, and the corresponding dynamic strain baseline data or dynamic deflection baseline data, the quasi-static strain or deflection measured values ​​of each test point are obtained. The theoretical calculation value acquisition module is used to calculate the strain or deflection of the bridge model at each test point based on the finite element mechanical model of the bridge to be evaluated and the total load effect value of each test point of the heavy transport vehicle passing through the bridge to be evaluated. The load-bearing capacity assessment module is used to calculate the verification coefficient of each test point based on the measured quasi-static strain or deflection values ​​and the calculated strain or deflection values, and to assess the load-bearing capacity based on the verification coefficients.

10. The system for evaluating the bearing capacity of bridge structures by load testing according to claim 9, characterized in that, The system also includes: The neutral axis height error acquisition module is used to fit a linear model of the edge beam strain based on the measured quasi-static strain values ​​of test points set on the web of the box girder and the distance from the bottom plate of the box girder; based on the linear model of the edge beam strain, the distance from the bottom plate of the box girder obtained when the measured quasi-static strain value is 0 is taken as the measured neutral axis height; based on the data of the box girder section, the distance from the bottom of the box girder to the neutral axis is calculated as the theoretical neutral axis height; and the neutral axis height error is obtained based on the measured neutral axis height and the theoretical neutral axis height. The load-bearing capacity assessment module is also used to assess the load-bearing capacity based on the verification coefficients of each test point and the neutral axis height error.

Images