Bridge floor damage assessment method based on crack detection

Abstract

The invention belongs to the technical field of bridge floor detection and evaluation, and discloses a bridge floor damage evaluation method based on crack detection, which comprises the following steps: an intelligent detection trolley inspects a bridge floor and identifies a single-lane bridge floor crack; eight vertexes of the three square areas are used as data acquisition points, eight intelligent detection trolleys are arranged, sampling time and sampling intervals are set, and acceleration time history data of each data acquisition point are acquired; calculating displacement time history data according to the acceleration time history data to form a node displacement vector of a certain square area; obtaining a projection coefficient of tension-compression deformation or shear deformation of a certain square area by using the base vector of the tension-compression deformation or shear deformation, and further obtaining a damage degree coefficient of the tension-compression deformation or shear deformation of the square crack area; and evaluating bridge floor damage, and taking corresponding measures.

Description

Technical Field

[0001] The present invention belongs to the technical field of bridge deck detection and evaluation, and relates to a method for evaluating bridge deck damage based on crack detection. Background Art

[0002] As an automated detection device combined with vision algorithms, intelligent inspection vehicles for bridges have been widely applied to the structural health monitoring of bridges and the investigation of potential safety hazards. Compared with traditional manual inspection methods, the inspection efficiency of intelligent inspection vehicles for bridges has been greatly improved, and they are more secure. In actual bridge disease detection, intelligent inspection vehicles can effectively identify cracks on the bridge deck, with an accuracy of up to 0.15 mm. However, the functions of existing intelligent inspection vehicles mainly focus on image recognition, and they can only identify cracks on the bridge deck, unable to determine whether the cracks have reached the level that affects the service performance of the structure. Therefore, there is an urgent need for an evaluation method to further evaluate the impact of cracks on the mechanical properties of the bridge structure based on crack recognition, so as to more accurately detect and evaluate the damage of the bridge deck. Summary of the Invention

[0003] Aiming at the technical problem that existing bridge deck crack detection cannot determine the impact of cracks on the service performance of bridges, the present invention provides a method for evaluating bridge deck damage based on crack detection, which can visually and quantitatively evaluate the deformation and damage degree of the structure at the crack damage location.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] The present invention provides a method for evaluating bridge deck damage based on crack detection, including the following steps:

[0006] a. The intelligent inspection vehicle conducts inspections on the bridge deck and identifies cracks on the single-lane bridge deck;

[0007] b. Using the single-lane width as the side length, mark a square crack area around the identified bridge deck crack and two adjacent square non-damaged areas on the left and right of the square crack area. Set up 8 intelligent inspection vehicles at the 8 vertices of the 3 square areas as data acquisition points, set the sampling time and sampling interval, and collect the acceleration time history data of each data acquisition point;

[0008] c. Calculate the displacement time history data from the acceleration time history data collected in step b), and retain the peak value of the displacement time history data of a certain data acquisition point within the sampling time to form the node displacement vector of a certain square area;

[0009] d. Using the tensile and compressive deformation basis vectors of the node displacement vector of the square area in the lane direction, the tensile and compressive deformation basis vectors in the direction perpendicular to the lane, and the shear deformation basis vector, obtain the projection coefficients of the tensile and compressive deformation vectors of a certain square area in the lane direction, the projection coefficients of the tensile and compressive deformation vectors in the direction perpendicular to the lane, and the projection coefficients of the shear deformation vector, and then obtain the damage degree coefficients of the tensile and compressive deformation vectors of the square crack area in the lane direction, the damage degree coefficients of the tensile and compressive deformation vectors in the direction perpendicular to the lane, and the damage degree coefficients of the shear deformation vector;

[0010] e. Based on the damage degree coefficients of the tensile and compressive deformation vectors of the square crack area in the lane direction, the damage degree coefficients of the tensile and compressive deformation vectors in the direction perpendicular to the lane, and the damage degree coefficients of the shear deformation vector, evaluate the bridge deck damage and take corresponding measures.

[0011] Furthermore, the projection coefficient r ia of the tensile and compressive deformation vector of a certain square area in the lane direction is calculated as follows:

[0012]

[0013] The projection coefficient r ib of the tensile and compressive deformation vector of a certain square area in the direction perpendicular to the lane is calculated as follows:

[0014]

[0015] The projection coefficient r ic of the shear deformation vector of a certain square area is calculated as follows:

[0016]

[0017] where d i is the node displacement vector of the i-th square area, i = 1, 2, 3; p a , p b , p c are the tensile and compressive deformation basis vectors of the square area in the lane direction, the tensile and compressive deformation basis vectors in the direction perpendicular to the lane, and the shear deformation basis vector respectively.

[0018] Furthermore, the damage degree coefficient λ a of the tensile and compressive deformation vector of the square crack area in the lane direction is calculated as follows:

[0019]

[0020] The damage degree coefficient λ b of the tensile and compressive deformation vector of the square crack area in the direction perpendicular to the lane is calculated as follows:

[0021]

[0022] The damage degree coefficient λ of the shear deformation vector in the square crack area c has the following calculation formula:

[0023]

[0024] Where: r 1a , r 2a , r 3a are the projection coefficients of the tensile and compressive deformation vectors of the left square non-damaged area, the square crack area, and the right square non-damaged area in the direction along the lane, respectively; r 1b , r 2b , r 3b are the projection coefficients of the tensile and compressive deformation vectors of the left square non-damaged area, the square crack area, and the right square non-damaged area in the direction perpendicular to the lane, respectively; r 1c , r 2c , r 3c are the projection coefficients of the shear deformation vectors of the left square non-damaged area, the square crack area, and the right square non-damaged area, respectively.

[0025] It should be noted that since the crack area is approximately equal to the mean state of two adjacent areas in the non-damaged state, the deviation degree (i.e., the damage degree coefficient) between the crack area and the mean state can be used to evaluate the damage of the crack to the mechanical properties of this area. When the damage degree coefficients of all three deformation vectors are less than 10%, it indicates that the deformation performance of the structure is basically safe; when the damage degree coefficient of any one deformation vector is greater than 10%, it indicates that the deformation performance of the structure is damaged greatly and needs reinforcement and maintenance; when the damage degree coefficient of any one deformation vector is greater than 50%, it indicates that the deformation performance of the structure is damaged very greatly and cannot be directly reinforced and maintained, and local component replacement or safe evacuation is required.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1) The present invention decomposes the comprehensive deformation of the square crack area into tensile and compressive deformation in the direction along the lane and tensile and compressive deformation in the direction perpendicular to the lane, further classifies and evaluates the damage degree, provides a basis for subsequent fine-matching reinforcement, and can reduce the comprehensive reinforcement cost.

[0028] 2) The present invention uses the damage degree coefficient of the square crack area in tensile and compressive deformation or shear deformation to quantitatively evaluate the damage degree of the bridge deck, and then takes corresponding measures, avoiding the subjectivity of traditional qualitative evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1Schematic layout diagram of the intelligent detection vehicle of the present invention. Detailed implementation manners

[0030] The following embodiments are used to illustrate the present invention, but are not used to limit the protection scope of the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. The test methods in the following embodiments are all conventional methods unless otherwise specified. The intelligent detection vehicle adopted by the present invention utilizes machine vision and is equipped with an image acquisition module and a path planning module, and can collect bridge deck crack images, such as a bridge crack detection system based on machine vision disclosed in the application publication number CN116597329A.

[0031] A method for evaluating bridge deck damage based on crack detection according to the present invention includes the following steps:

[0032] a. The intelligent detection vehicle patrols the bridge deck and identifies the cracks in a single-lane bridge deck;

[0033] b. Taking the width of a single lane as the side length, mark a square crack area and two adjacent square non-damaged areas on the left and right of the identified bridge deck crack. Using the 8 vertices of the 3 square areas as data acquisition points and deploying 8 intelligent detection vehicles, set the sampling time and sampling interval, and collect the acceleration time history data of each data acquisition point;

[0034] c. Calculate the displacement time history data from the acceleration time history data collected in step b), and retain the peak value of the displacement time history data of a certain data acquisition point within the sampling time to form the node displacement vector of a certain square area, denoted as:

[0035] d i =[d 1x d 1y d 2x d 2y d 3x d 3y d 4x d 4y ;

[0036] d. Utilize the tensile and compressive deformation basis vectors in the lane direction, the tensile and compressive deformation basis vectors in the direction perpendicular to the lane, and the shear deformation basis vectors of the node displacement vector of the square area to obtain the projection coefficients of the tensile and compressive deformation vectors in the lane direction, the projection coefficients of the tensile and compressive deformation vectors in the direction perpendicular to the lane, and the projection coefficients of the shear deformation vector of a certain square area, and further obtain the damage degree coefficients of the tensile and compressive deformation vectors in the lane direction, the damage degree coefficients of the tensile and compressive deformation vectors in the direction perpendicular to the lane, and the damage degree coefficients of the shear deformation vector of the square crack area;

[0037] e. Evaluate the bridge deck damage based on the damage degree coefficients of the tensile and compressive deformation vectors in the longitudinal lane direction, the tensile and compressive deformation vectors in the transverse lane direction, and the shear deformation vector of the square crack area, and take corresponding measures.

[0038] Application Example 1

[0039] Taking a three-span continuous box girder bridge with a bridge length of 90 m as an example, the single-span length is 30 m, there are 4 lanes in both directions, and the single-lane width is 3.5 m. Use the intelligent detection trolley to determine the mid-span crack area of the middle span, and mark the left square non-damaged area, the square crack area, and the right square non-damaged area as No. ①, No. ②, and No. ③ in sequence. At Figure 1 Arrange 8 intelligent detection trolleys at the square vertex positions shown, set the sampling frequency to 200 Hz, the interval to 0.005 s, and collect the acceleration time history data of each data acquisition point. Use finite element numerical simulation to simulate the displacement data obtained from actual detection, and illustrate with the following two working conditions.

[0040] Working Condition 1: There are small cracks on the bridge deck surface, but there is no damage to components such as the lower box girder.

[0041] The node displacement vector of the No. ① non-damaged area is (unit: m):

[0042] d1 = [0.0100 0.0055 -0.0106 0.0055 -0.0115 -0.0050 0.0115 -0.0055];

[0043] The node displacement vector of the No. ② crack area is (unit: m):

[0044] d2 = [0.0115 0.0060 -0.0110 0.0050 -0.0120 -0.0045 0.0110 -0.0060];

[0045] The node displacement vector of the No. ③ non-damaged area is (unit: m):

[0046] d3 = [0.0100 0.0060 -0.0105 0.0055 -0.0110 -0.0055 0.0115 -0.0060];

[0047] The tensile and compressive deformation base vectors of the square area in the longitudinal lane direction are as follows:

[0048] p a = [0.5 0 -0.5 0 -0.5 0 0.5 0];

[0049] The tensile and compressive deformation base vectors of the square area in the transverse lane direction are as follows:

[0050] p b = [0 0.5 0 0.5 0 -0.5 0 -0.5];

[0051] The base vectors of the shear deformation of the square area are as follows:

[0052]

[0053] Using formulas 1 - 3, calculate the projection coefficients of the tensile and compressive deformation vectors of the No. ① non-damaged area, the No. ② crack area, and the No. ③ non-damaged area in the longitudinal lane direction, the projection coefficients of the tensile and compressive deformation vectors in the vertical lane direction, and the projection coefficients of the shear tensile and compressive deformation vectors, that is, r 1a = 0.02180, r 2a = 0.02275, r 3a = 0.02150, r 1b = 0.01075, r 2b = 0.01075, r 3b = 0.01150, r 1c = 0.0003889, r 2c = 0.0003536, r 3c = 0.0003536.

[0054] Using formulas 4 - 5, calculate the damage degree coefficients of the tensile and compressive deformation vectors of the No. ② crack area in the longitudinal lane direction, the damage degree coefficients of the tensile and compressive deformation vectors in the vertical lane direction, and the damage degree coefficient of the shear deformation vector, that is, λ a

[0055] = 5.08%, λ b = 3.37%, λ c = 4.75%.

[0056] The results show that the damage degree coefficients of the three deformation vectors in the square crack area are less than 10%, indicating that the deformation performance of the structure is basically safe.

[0057] Condition 2: There are medium and small cracks on the bridge deck surface, and there are hidden tensile and compressive deformation damages in the longitudinal lane direction in the lower box girder.

[0058] The displacement vector of the No. ① non-damaged area is (unit: m)

[0059] d1 = [0.0300 0.0165 -0.0318 0.0165 -0.0345 -0.0150 0.0345 -0.0165]

[0060] The displacement vector of the No. ② crack area is (unit: m)

[0061] d2 = [0.0445 0.0180 -0.0430 0.0150 -0.0460 -0.0135 0.0430 -0.0180]

[0062] The displacement vector of the No. ③ non-damaged area is (unit: m)

[0063] d3 = [0.0300 0.0180 -0.0315 0.0165 -0.0330 -0.0165 0.0345 -0.0180]

[0064] The tension-compression deformation base vectors of the square area in the lane direction are as follows:

[0065] p a = [0.5 0 -0.5 0 -0.5 0 0.5 0];

[0066] The tension-compression deformation base vectors of the square area in the direction perpendicular to the lane are as follows:

[0067] p b = [0 0.5 0 0.5 0 -0.5 0 -0.5];

[0068] The shear deformation base vectors of the square area are as follows:

[0069]

[0070] Using formulas 1-3, calculate the projection coefficients of the tension-compression deformation vectors of the No. ① non-damaged area, the No. ② crack area, and the No. ③ non-damaged area in the lane direction, the projection coefficients of the tension-compression deformation vectors in the direction perpendicular to the lane, and the projection coefficients of the shear tension-compression deformation vectors, that is, r 1a = 0.06540, r 2a = 0.08825, r 3a = 0.06450, r 1b = 0.03225, r 2b = 0.03225, r 3b = 0.03450, r 1c = 0.001167, r 2c = 0.001061, r 3c = 0.001061.

[0071] Using formulas 4-5, calculate the damage degree coefficients of the tension-compression deformation vectors of the No. ② crack area in the lane direction, the tension-compression deformation vectors in the direction perpendicular to the lane, and the shear deformation vectors, that is, λ a

[0072] = 35.87%, λ b= 3.37%, λ c = 4.76%.

[0073] The projection coefficient of the tensile and compressive deformation vector of the square crack area in the vehicle lane direction is greater than 10% and less than 50%, indicating that the tensile and compressive deformation performance of the structure in the vehicle lane direction is severely damaged and needs to be strengthened and maintained; the damage degree coefficients of the tensile and compressive deformation vector and the shear deformation vector of the square crack area in the direction perpendicular to the vehicle lane are less than 10%, indicating that the deformation performance of the structure in these two directions is basically safe.

[0074] The above-described embodiments are only the preferred embodiments of the present invention, which are only used to explain the present invention and do not limit the scope of implementation of the present invention. For those skilled in the art of this technology, of course, other implementation manners can be easily made by means of substitution or change according to the technical content disclosed in this specification. Therefore, all changes and improvements made on the principle of the present invention should be included in the scope of the patent application of the present invention.

Claims

1. A bridge deck damage assessment method based on crack detection, characterized in that It includes the following steps: a. The intelligent inspection vehicle conducts inspections on the bridge deck and identifies single-lane bridge deck cracks; b. Taking the single-lane width as the side length, mark a square crack area around the identified bridge deck crack and two adjacent square non-damaged areas on the left and right of the square crack area. Use the 8 vertices of the 3 square areas as data acquisition points and deploy 8 intelligent inspection vehicles. Set the sampling time and sampling interval, and collect the acceleration time history data of each data acquisition point; c. Calculate the displacement time history data from the acceleration time history data collected in step b), and retain the peak value of the displacement time history data of a certain data acquisition point within the sampling time to form the nodal displacement vector of a certain square area; d. Use the tensile and compressive deformation basis vectors in the longitudinal lane direction, the tensile and compressive deformation basis vectors in the perpendicular lane direction, and the shear deformation basis vector of the nodal displacement vector of the square area to obtain the projection coefficients of the tensile and compressive deformation vectors in the longitudinal lane direction, the projection coefficients of the tensile and compressive deformation vectors in the perpendicular lane direction, and the projection coefficients of the shear deformation vector of a certain square area, and then obtain the damage degree coefficients of the tensile and compressive deformation vectors in the longitudinal lane direction, the damage degree coefficients of the tensile and compressive deformation vectors in the perpendicular lane direction, and the damage degree coefficients of the shear deformation vector of the square crack area; e. Evaluate the bridge deck damage based on the damage degree coefficients of the tensile and compressive deformation vectors in the longitudinal lane direction, the damage degree coefficients of the tensile and compressive deformation vectors in the perpendicular lane direction, and the damage degree coefficients of the shear deformation vector of the square crack area, and take corresponding measures.

2. The method for evaluating bridge deck damage based on crack detection according to claim 1, wherein The projection coefficient r of the tensile and compressive deformation vector of a certain square area in the lane direction ia is calculated as follows: The projection coefficient r of the tensile and compressive deformation vector of a certain square area in the direction perpendicular to the lane ib is calculated as follows: The projection coefficient r of the shear deformation vector of a certain square region ic is calculated as follows: where d i is the nodal displacement vector of the i-th square region, i = 1, 2, 3; p a , p b , p c are the tensile and compressive deformation base vectors of the square region in the longitudinal lane direction, the tensile and compressive deformation base vectors in the direction perpendicular to the lane, and the shear deformation base vector, respectively.

3. The method for evaluating bridge deck damage based on crack detection according to claim 1 or 2, characterized in that, The damage degree coefficient λ of the tensile and compressive deformation vector of the square crack area in the vehicle lane direction a is calculated as follows: The damage degree coefficient λ of the tensile and compressive deformation vectors of the square crack region in the direction perpendicular to the lane b has the following calculation formula: The damage degree coefficient λ of the shear deformation vector in the square crack region c has the following calculation formula: where: r 1a , r 2a , r 3a are the projection coefficients of the tensile and compressive deformation vectors of the left square non-damaged area, the square crack area, and the right square non-damaged area in the longitudinal lane direction, respectively; r 1b , r 2b , r 3b are the projection coefficients of the tensile and compressive deformation vectors of the left square non-damaged area, the square crack area, and the right square non-damaged area in the transverse lane direction, respectively; r 1c , r 2c , r 3c are the projection coefficients of the shear tensile and compressive deformation vectors of the left square non-damaged area, the square crack area, and the right square non-damaged area, respectively.

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