A bridge stiffness measurement method, system and device based on vehicle-mounted sensing

Abstract

The application discloses a bridge stiffness measurement method, system and device based on vehicle-mounted sensing, which first calculates the deflection difference between two points of a bridge at each measurement point position of the bridge. Secondly, the deflection difference of the bridge between the front and rear sensor groups when a vehicle travels to each measurement point is established. Then, the above two deflection differences are equalized, and the least square method is used to linearly fit the deflection difference of the bridge between n front and rear sensor groups to obtain a bridge stiffness equation. Finally, the front and rear wheel positions of the measurement vehicle at each measurement point position of the bridge and two vertical static loads acting on the bridge surface are brought into the bridge stiffness equation to obtain the measured bridge stiffness. The application adopts the least square method to linearly fit the deflection difference of the bridge between n front and rear sensor groups, finds the best function matching of data by minimizing the sum of squares of errors, obtains the bridge stiffness equation, and directly brings the parameters into the bridge stiffness equation, so that the calculation speed of the measured bridge stiffness can be improved, and the calculation accuracy of the measured bridge stiffness can be improved.

Description

Technical Field

[0001] This invention belongs to the field of bridge engineering measurement technology, specifically relating to a bridge stiffness measurement method, system, and device based on vehicle-mounted sensing. Background Technology

[0002] Bridges are critical nodes in transportation infrastructure, and their performance inevitably deteriorates with age. Accurately assessing the service condition of bridge structures is a key challenge and a major concern for bridge maintenance departments, ensuring their safe operation. Bridge inspection is an effective technical means of evaluating bridge service condition, and bridge stiffness is one of the key parameters reflecting this condition. Given the large number and wide distribution of bridge structures, quickly determining their stiffness is a pressing technical problem that needs to be solved.

[0003] Traditional methods for determining bridge stiffness rely on bridge deflection. Currently, commonly used deflection testing methods include: leveling, static leveling, and displacement gauge testing. Leveling requires numerous elevation test points on the bridge deck, using the elevation difference between these points and stationary points outside the bridge to reflect the deflection. This method is slow and prone to error. Static leveling utilizes the principle of communicating vessels to measure bridge deflection, but this method has a long response time and is unsuitable for rapid testing. Displacement gauge testing requires scaffolding to place the gauges at the bottom of the bridge for contact measurement, which is time-consuming and labor-intensive, making it difficult to implement when the bridge crosses valleys or rivers. In summary, traditional stiffness calculation methods suffer from slow testing speed and low accuracy.

[0004] Currently, my country has over 900,000 highway bridges, and the shortcomings of traditional bridge stiffness testing methods are becoming increasingly apparent, failing to adequately meet the demands of bridge inspection work. Therefore, there is an urgent need to provide a bridge stiffness testing method that is fast and highly accurate. Summary of the Invention

[0005] To address the aforementioned technical issues, this invention provides a method, system, and device for measuring bridge stiffness based on vehicle-mounted sensors, enabling rapid and accurate detection of bridge stiffness.

[0006] This invention provides a method for measuring bridge stiffness based on vehicle-mounted sensors, comprising:

[0007] The deflection difference between two points on the bridge at each measurement point is calculated based on the relationship between distance and inclination angle.

[0008] Based on the principles of structural mechanics, the bridge deflection difference between the front and rear sensor groups is established when the vehicle travels to each measurement point.

[0009] Let the deflection difference between two points on the bridge at each measurement point be equal to the bridge deflection difference between the front and rear sensor groups at each measurement point. Then, use the least squares method to linearly fit the bridge deflection difference between n front and rear sensor groups to obtain the bridge stiffness equation; where n is a positive integer greater than 1.

[0010] The measurements were taken at various points on the bridge, measuring the positions of the front and rear wheels of the measuring vehicle and the two static loads acting perpendicularly on the bridge deck.

[0011] The bridge stiffness is obtained by substituting the positions of the front and rear wheels of the measuring vehicle at each measuring point on the bridge and the two static loads acting perpendicularly to the bridge deck into the bridge stiffness equation.

[0012] Optionally, the calculation of the deflection difference between two points on the bridge at each measurement point location based on the relationship between distance and inclination angle specifically includes:

[0013] The distance from each laser rangefinder to the bridge deck at each measurement point on the bridge is measured using laser rangefinders.

[0014] The horizontal lateral tilt angle of the measuring vehicle at each measuring point on the bridge is measured using various tilt sensors.

[0015] The vertical distance from the bottom of the measuring vehicle to the bridge surface at each measuring point is determined based on the distance from each laser rangefinder to the bridge surface at each measuring point and the horizontal tilt angle of the measuring vehicle.

[0016] The deflection difference between two points on the bridge at each measurement point is determined by the vertical distance from the bottom of the measuring vehicle to the bridge deck.

[0017] Optionally, establishing the bridge deflection difference between the front and rear sensor groups when the vehicle travels to each measurement point based on structural mechanics principles specifically includes:

[0018] Based on the principles of structural mechanics, the bridge deflection at the position of the front sensor group and the position of the rear sensor group are established when the vehicle travels to each measurement point under the action of the vehicle's gravity.

[0019] The difference in bridge deflection between the front and rear sensor groups is calculated based on the bridge deflection at the locations of the front and rear sensor groups of the vehicle.

[0020] Optionally, at the location of the vehicle's rear sensor group at the i-th measurement point on the bridge, the bridge deflection Δ i1 The formula is:

[0021]

[0022] Where, Δ i1 This represents the bridge deflection at the location of the vehicle's rear sensor group at the i-th measurement point on the bridge. M represents the bending moment function generated by the bridge when the measuring vehicle is located at the i-th measuring point and the front wheels are engaged. Pi1 Let ds represent the bending moment function at the front wheel position under a unit load when the measuring vehicle is at the i-th measuring point, ds represent the line integral, EI represent the stiffness of the bridge under test, and P1 and P2 represent the forces exerted by the measuring vehicle on the bridge deck, which are equivalently simplified to two static loads acting perpendicularly on the bridge deck. i1 This indicates that the position of the rear wheel of the vehicle is measured at the i-th measurement point on the bridge, x. i2 This indicates that the position of the front wheel of the vehicle is measured at the i-th measurement point on the bridge, and L represents the length of the bridge.

[0023] Optionally, at the location of the i-th measurement point on the bridge, at the location of the sensor group in front of the vehicle, the bridge deflection Δ i2 The formula is:

[0024]

[0025] Where, Δ i2 This represents the bridge deflection at the location of the vehicle's front sensor group at the i-th measurement point on the bridge. M represents the bending moment function of the bridge when the measuring vehicle is at the i-th measuring point, caused by the action of the rear wheels. P i2 represents the bending moment function at the rear wheel position under unit load when the measuring vehicle is at the i-th measuring point, ds represents the line integral, EI represents the stiffness of the bridge under test, P1 and P2 represent the forces exerted by the measuring vehicle on the bridge deck, which are equivalently simplified to two static loads acting perpendicularly on the bridge deck, x i1 This indicates that the position of the rear wheel of the vehicle is measured at the i-th measurement point on the bridge, x. i2 This indicates that the position of the front wheel of the vehicle is measured at the i-th measurement point on the bridge, and L represents the length of the bridge.

[0026] Optionally, the deflection difference between two points on the bridge at each measurement point is set equal to the deflection difference between the front and rear sensor groups at each measurement point. The least squares method is then used to linearly fit the deflection differences between the n front and rear sensor groups to obtain the bridge stiffness equation. The specific formula is as follows:

[0027]

[0028]

[0029]

[0030] Δd' i =Δ i ;

[0031] Where, Δ iThis represents the bridge deflection difference between the front and rear sensor groups at the i-th measurement point on the bridge, where L is the bridge length, EI represents the stiffness of the bridge under test, and P1 and P2 represent the forces exerted by the measuring vehicle on the bridge deck, which are equivalently simplified to two static loads acting perpendicularly on the bridge deck. i1 This indicates that the position of the rear wheel of the vehicle is measured at the i-th measurement point on the bridge, x. i2 This indicates that the position of the front wheel of the vehicle is measured at the i-th measurement point on the bridge, where n represents the total number of measurement points on the bridge, and Δd' i This represents the difference in deflection between two points on the bridge at the i-th measurement point.

[0032] The present invention also provides a bridge stiffness measurement system based on vehicle-mounted sensors, the system comprising:

[0033] The first deflection difference determination module is used to calculate the deflection difference between two points on the bridge at each measurement point location based on the relationship between distance and tilt angle.

[0034] The second deflection difference determination module is used to establish the bridge deflection difference between the front and rear sensor groups when the vehicle travels to each measurement point, based on the principles of structural mechanics.

[0035] The bridge stiffness equation establishment module is used to set the deflection difference between two points on the bridge at each measurement point to be equal to the bridge deflection difference between the front and rear sensor groups at each measurement point. The least squares method is used to linearly fit the bridge deflection difference between n front and rear sensor groups to obtain the bridge stiffness equation; where n is a positive integer greater than 1.

[0036] The measurement module is used to measure the positions of the front and rear wheels of the measuring vehicle at various measurement points on the bridge, as well as two static loads acting perpendicularly to the bridge deck.

[0037] The module for obtaining the stiffness of the bridge under test is used to input the positions of the front and rear wheels of the measuring vehicle at each measurement point on the bridge and the two static loads acting perpendicularly to the bridge deck into the bridge stiffness equation to obtain the stiffness of the bridge under test.

[0038] Optionally, the second deflection difference determination module specifically includes:

[0039] The bridge deflection determination unit at the positions of the front and rear sensor groups of the vehicle is used to establish the bridge deflection at the positions of the front and rear sensor groups of the vehicle under the action of the vehicle's gravity when the vehicle travels to each measurement point, based on the principles of structural mechanics.

[0040] The bridge deflection difference calculation unit between the front and rear sensor groups is used to calculate the bridge deflection difference between the front and rear sensor groups based on the bridge deflection at the positions of the front and rear sensor groups of the vehicle.

[0041] Optionally, the deflection difference between two points on the bridge at each measurement point is set equal to the deflection difference between the front and rear sensor groups at each measurement point. The least squares method is then used to linearly fit the deflection differences between the n front and rear sensor groups to obtain the bridge stiffness equation. The specific formula is as follows:

[0042]

[0043]

[0044]

[0045] Δd' i =Δ i ;

[0046] Where, Δ i This represents the bridge deflection difference between the front and rear sensor groups at the i-th measurement point on the bridge, where L is the bridge length, EI represents the stiffness of the bridge under test, and P1 and P2 represent the forces exerted by the measuring vehicle on the bridge deck, which are equivalently simplified to two static loads acting perpendicularly on the bridge deck. i1 This indicates that the position of the rear wheel of the vehicle is measured at the i-th measurement point on the bridge, x. i2 This indicates that the position of the front wheel of the vehicle is measured at the i-th measurement point on the bridge, where n represents the total number of measurement points on the bridge, and Δd' i This represents the difference in deflection between two points on the bridge at the i-th measurement point.

[0047] The present invention also provides a bridge stiffness measurement device based on vehicle-mounted sensors, the device comprising:

[0048] Two laser rangefinders are installed on the bottom of the measuring vehicle to measure the distance from each laser rangefinder to the bridge deck at each measuring point on the bridge.

[0049] Two tilt sensors are installed on the bottom of the measuring vehicle to measure the horizontal tilt angle of the vehicle at various measuring points on the bridge.

[0050] The calculation module is connected to each laser rangefinder and each tilt sensor, and is used to determine the stiffness of the bridge under test using the method described above.

[0051] Compared with the prior art, the present invention has the following advantages:

[0052] This invention discloses a method, system, and device for measuring bridge stiffness based on vehicle-mounted sensors. The method includes: first, calculating the deflection difference between two points on the bridge at each measurement point based on the relationship between distance and inclination angle; second, establishing the bridge deflection difference between the front and rear sensor groups when the vehicle travels to each measurement point using structural mechanics principles; third, setting the deflection difference between two points on the bridge at each measurement point equal to the bridge deflection difference between the front and rear sensor groups at each measurement point, and using the least squares method to linearly fit the bridge deflection differences between n front and rear sensor groups to obtain the bridge stiffness equation; then, measuring the positions of the front and rear wheels of the measuring vehicle and two static loads perpendicular to the bridge deck at each measurement point; finally, substituting the positions of the front and rear wheels of the measuring vehicle and the two static loads perpendicular to the bridge deck at each measurement point into the bridge stiffness equation to obtain the stiffness of the bridge under test. This invention employs the least squares method to linearly fit the bridge deflection difference between n front and rear sensor groups. By minimizing the sum of squared errors, it finds the optimal function match for the data to obtain the bridge stiffness equation. Subsequently, the positions of the front and rear wheels of the measuring vehicle and the two static loads acting perpendicularly on the bridge deck can be directly substituted into the bridge stiffness equation. This not only improves the calculation speed of the stiffness of the bridge under test but also improves the calculation accuracy, avoiding the cumbersome process of setting up instruments on-site during traditional bridge testing. Attached Figure Description

[0053] Figure 1 This invention discloses a flowchart of a bridge stiffness measurement method based on vehicle-mounted sensors;

[0054] Figure 2 This is a schematic diagram of the sensor installation and measurement vehicle disclosed in this invention;

[0055] Figure 3 This is a schematic diagram of the force analysis of the measuring vehicle on the bridge surface disclosed in this invention;

[0056] Figure 4 This is a schematic diagram of the conventional force analysis of the measuring vehicle disclosed in this invention;

[0057] Figure 5 This is a schematic diagram illustrating the relationship between distance and tilt angle disclosed in this invention;

[0058] Figure 6 This is a simplified schematic diagram of the overall stress on the bridge under the action of the measuring vehicle disclosed in this invention;

[0059] Figure 7 This invention discloses a structural diagram of a bridge stiffness measurement system based on vehicle-mounted sensors;

[0060] Figure 8 This is a schematic diagram of the overall bridge disclosed in this invention;

[0061] Figure 9 This invention discloses a cross-sectional dimension diagram of a bridge.

[0062] Among them, 1 is a laser rangefinder, 2 is a tilt sensor, 3 is a measuring vehicle, and 4 is a bridge deck. Detailed Implementation

[0063] The present invention will be further described below with reference to specific implementation examples and accompanying drawings, but the present invention is not limited to these embodiments.

[0064] Example 1

[0065] like Figure 1 As shown, this invention discloses a method for measuring bridge stiffness based on vehicle-mounted sensors, the method comprising:

[0066] Step S1: Calculate the deflection difference between two points on the bridge at each measurement point location based on the relationship between distance and tilt angle.

[0067] Step S2: Using the principles of structural mechanics, establish the bridge deflection difference between the front and rear sensor groups when the vehicle travels to each measurement point.

[0068] Step S3: Set the deflection difference between two points on the bridge at each measurement point to be equal to the bridge deflection difference between the front and rear sensor groups at each measurement point. Then, use the least squares method to linearly fit the bridge deflection difference between the n front and rear sensor groups to obtain the bridge stiffness equation; where n is a positive integer greater than 1.

[0069] Step S4: Measure the positions of the front and rear wheels of the measuring vehicle 3 and the two static loads acting perpendicularly on the bridge deck 4 at various measuring points on the bridge.

[0070] Step S5: Substitute the positions of the front and rear wheels of the measuring vehicle 3 at each measuring point on the bridge and the two static loads acting perpendicularly on the bridge deck 4 into the bridge stiffness equation to obtain the stiffness of the bridge to be measured.

[0071] The following is a detailed discussion of each step:

[0072] Step S1: Calculate the deflection difference between two points on the bridge at each measurement point location based on the relationship between distance and inclination angle. This specifically includes:

[0073] Step S11: Use each laser rangefinder 1 to measure the distance d from each laser rangefinder 1 to the bridge deck 4 at each measurement point on the bridge. i1 d i2This invention requires two laser rangefinder sensors 1 and two tilt sensors 2. One laser rangefinder sensor 1 and one tilt sensor 2 are designated as the first group, referred to as the front sensor group; the other laser rangefinder sensor 1 and the other tilt sensor 2 are designated as the second group, referred to as the rear sensor group. The rear sensor group is positioned at a distance a1 from the rear wheel of the measuring vehicle 3, and the front sensor group is positioned at a distance a2 from the front wheel of the measuring vehicle 3. The two sensor groups are positioned between the front and rear wheels, with the laser rangefinder sensor 1 and tilt sensor 2 correspondingly configured in each group. See details below. Figure 2 .

[0074] Step S12: Measure the horizontal lateral tilt angle θ of the measuring vehicle 3 at each measuring point on the bridge using each tilt sensor 2. i1 θ i2 .

[0075] Step S13: Determine the vertical distance from the bottom of the measuring vehicle 3 to the bridge surface 4 at each measuring point location based on the distance from each laser ranging sensor 1 to the bridge surface 4 and the horizontal tilt angle of the measuring vehicle 3. The specific calculation formula is as follows:

[0076] d' i1 =d i1 ·cosθ i1 ;

[0077] d' i2 =d i2 ·cosθ i2 ;

[0078] Where, d i1 d represents the distance from the first laser ranging sensor 1 at the i-th measurement point on the bridge to the bridge deck 4. i2 θ represents the distance from the second laser ranging sensor 1 at the i-th measurement point on the bridge to the bridge deck 4. i1 This indicates that at the i-th measurement point on the bridge, the first tilt sensor 2 measures the horizontal lateral tilt angle of the measuring vehicle 3, θ. i2 This indicates that at the i-th measurement point on the bridge, the second tilt sensor 2 measures the horizontal lateral tilt angle of the measuring vehicle 3, d'. i1 ,d' i2 These represent the vertical distances from the bottom of the measuring vehicle 3 to the bridge surface 4.

[0079] Because the two laser rangefinder sensors 1 are identical, and the two tilt sensors 2 are identical, the specific relationship between distance and tilt angle is illustrated using a set of sensors. See details below. Figure 5 ,visible Figure 5 In Chinese, d represents d i1 and d i2 Let θ represent θ i1 and θ i2Let d' represent d' i1 ,d' i2 .

[0080] Step S14: Determine the deflection difference between two points on the bridge at each measurement point location based on the vertical distance from the bottom of the measuring vehicle 3 to the bridge deck 4. The specific formula is as follows:

[0081] Δd' i =|d' i2 -d' i1 |;

[0082] Where, Δd' i d' represents the deflection difference between two points on the bridge at the i-th measurement point. i1 ,d' i2 These represent the vertical distances from the bottom of the measuring vehicle 3 to the bridge surface 4.

[0083] To improve measurement accuracy, this invention sets up n measurement points on the bridge and measures each measurement point sequentially, thus obtaining the bridge deflection vector matrix.

[0084] Step S14: Determine the bridge deflection vector matrix based on the deflection difference between two points on the bridge at each measurement point location. The specific formula is as follows:

[0085] Δd'=[Δd'1,Δd'2,···,Δd' n-1 ,Δd' n ] T ;

[0086] Where, Δd' i Δd' represents the deflection difference between two points on the bridge at the i-th measurement point, and Δd' represents the bridge deflection vector matrix.

[0087] Figure 3 The specific stress analysis of the measuring vehicle 3 on the bridge is given. Figure 4 This is a schematic diagram of the conventional force analysis of the measuring vehicle 3 disclosed in this invention. Figure 3 The letters in part A and Figure 4 The letters in the same column are identical; see details below. Figure 4 , where k s1 k s2 These represent the stiffness of the front and rear body sections, respectively, k t1 k t2 These represent the stiffness of the front and rear tires, respectively. s1 c s2 These represent the damping of the front and rear of the vehicle body, respectively. t1 c t2 These represent the front and rear tire damping, respectively, m t1 m t2Let a1 and a2 represent the masses of the front and rear wheels, respectively, and let d1 and d2 represent the distances from the rear sensor group to the rear wheel and the front sensor group to the front wheel, respectively. Then, d1 and d2 are the distances from the two laser sensors at a certain measurement point to the bridge surface 4. Therefore, based on the principles of structural mechanics, the bridge deflection difference between the front and rear sensor groups can be directly constructed. The specific steps are as follows:

[0088] Step S2: Using structural mechanics principles, establish the bridge deflection difference between the front and rear sensor groups as the vehicle travels to each measurement point, specifically including:

[0089] Step S21: Using structural mechanics principles, establish the bridge deflection at the position of the front sensor group and the position of the rear sensor group under the vehicle's gravity when the vehicle travels to each measurement point; the specific forces are as follows: Figure 3 and Figure 4 As shown.

[0090] The bridge deflection Δ at the location of the vehicle's rear sensor group at the i-th measurement point on the bridge. i1 The formula is:

[0091]

[0092] The bridge deflection Δ at the location of the vehicle's front sensor group at the i-th measurement point on the bridge. i2 The formula is:

[0093]

[0094] Where, Δ i1 Δ represents the bridge deflection at the location of the rear sensor group of the vehicle at the i-th measurement point on the bridge. i2 This represents the bridge deflection at the location of the sensor group in front of the vehicle at the i-th measurement point on the bridge, where L is the bridge length. This represents the bending moment function generated by the bridge when the front wheels of the measuring vehicle 3 are at the i-th measuring point. M represents the bending moment function of the bridge when the rear wheels of the measuring vehicle 3 are at the i-th measuring point. Pi1 M represents the bending moment function at the position of the front wheel under a unit load when the measuring vehicle 3 is located at the i-th measuring point. Pi2 Let ds represent the bending moment function at the rear wheel position under a unit load when the measuring vehicle 3 is located at the i-th measuring point, ds represent the line integral, EI represent the stiffness of the bridge under test, and P1 and P2 represent the forces exerted by the measuring vehicle 3 on the bridge deck 4, which are equivalently simplified to two static loads acting perpendicularly on the bridge deck 4. i1 This indicates that the position of the rear wheel of vehicle 3 is measured at the i-th measurement point on the bridge. i2 This indicates the position of the front wheel of vehicle 3 at the i-th measurement point on the bridge.

[0095] Step S22: Calculate the bridge deflection difference between the front and rear sensor groups based on the bridge deflection at the positions of the front and rear sensor groups of the vehicle. The specific formula is as follows:

[0096]

[0097] Where, Δ i Δ represents the difference in bridge deflection between the front and rear sensor groups at the i-th measurement point on the bridge. i1 Δ represents the bridge deflection at the location of the rear sensor group of the vehicle at the i-th measurement point on the bridge. i2 This represents the bridge deflection at the location of the sensor group in front of the vehicle at the i-th measurement point on the bridge, where L is the bridge length, EI represents the stiffness of the bridge under test, and P1 and P2 represent the forces exerted by the measuring vehicle 3 on the bridge deck 4, which are equivalently simplified to two static loads acting perpendicularly on the bridge deck 4. i1 This indicates that the position of the rear wheel of vehicle 3 is measured at the i-th measurement point on the bridge. i2 This indicates the position of the front wheel of vehicle 3 at the i-th measurement point on the bridge.

[0098] Step S3: Set the deflection difference between any two points on the bridge at each measurement point to be equal to the deflection difference between the preceding and following sensor groups at each measurement point. Then, use the least squares method to linearly fit the deflection differences between the n preceding and following sensor groups to obtain the bridge stiffness equation. The specific formula is as follows:

[0099]

[0100]

[0101]

[0102] Δd' i =Δ i ;

[0103] Where, Δ i This represents the bridge deflection difference between the front and rear sensor groups at the i-th measurement point on the bridge, where L is the bridge length, EI represents the stiffness of the bridge under test, and P1 and P2 represent the forces exerted by the measuring vehicle 3 on the bridge deck 4, which are equivalently simplified to two static loads acting perpendicularly on the bridge deck 4. i1 This indicates that the position of the rear wheel of vehicle 3 is measured at the i-th measurement point on the bridge. i2 This indicates the position of the front wheel of vehicle 3 at the i-th measurement point on the bridge, where n represents the total number of measurement points on the bridge, and Δd' i This represents the difference in deflection between two points on the bridge at the i-th measurement point.

[0104] Step S4: Measure the positions of the front and rear wheels of the measuring vehicle 3 and the two static loads acting perpendicularly on the bridge deck 4 at various measuring points on the bridge.

[0105] Figure 6 The present invention discloses a simplified diagram of the overall force distribution on a bridge under the action of the measuring vehicle 3. The forces exerted by the two wheels on the bridge surface 4 are simplified to P1 and P2, and the positions of the front and rear wheels at the i-th measurement point of the vehicle action are x and x, respectively. i1 x i2 , Figure 6 The positions of the front and rear wheels are generally represented by x1 and x2. x represents the horizontal direction and y represents the vertical direction.

[0106] This invention measures the positions of the front and rear wheels of a measuring vehicle 3 at various measuring points on a bridge using a distance measurement method. Therefore, the front wheel position vector x1 and the rear wheel position vector x2 can be obtained. The specific formula is: x1 = [x...]. 11 ,x 21 ,···,x (n-1)1 ,x n1 ] T x2=[x 12 ,x 22 ,···,x (n-1)2 ,x n2 ] T ;where x i1 This indicates the position of the rear wheel of vehicle 3 measured at various measurement points on the bridge, x i2 This indicates the position of the front wheel of vehicle 3 at each measurement point on the bridge.

[0107] Step S5: Substitute the positions of the front and rear wheels of the measuring vehicle 3 at each measuring point on the bridge and the two static loads acting perpendicularly on the bridge deck 4 into the bridge stiffness equation to obtain the stiffness EI of the bridge to be measured.

[0108] Example 2

[0109] like Figure 7 As shown, the present invention also discloses a bridge stiffness measurement system based on vehicle-mounted sensors, the system comprising:

[0110] The first deflection difference determination module 701 is used to calculate the deflection difference between two points on the bridge at each measurement point location based on the relationship between distance and inclination angle.

[0111] The second deflection difference determination module 702 is used to establish the bridge deflection difference between the front and rear sensor groups when the vehicle travels to each measurement point using the principles of structural mechanics.

[0112] The bridge stiffness equation establishment module 703 is used to set the deflection difference between two points on the bridge at each measurement point to be equal to the bridge deflection difference between the front and rear sensor groups at each measurement point, and to use the least squares method to linearly fit the bridge deflection difference between n front and rear sensor groups to obtain the bridge stiffness equation; where n is a positive integer greater than 1.

[0113] The measurement module 704 is used to measure the positions of the front and rear wheels of the measuring vehicle 3 at various measurement points on the bridge and the two static loads acting perpendicularly on the bridge deck 4.

[0114] The bridge stiffness calculation module 705 is used to input the positions of the front and rear wheels of the measuring vehicle 3 at each measurement point on the bridge and the two static loads acting perpendicularly on the bridge deck 4 into the bridge stiffness equation to obtain the stiffness of the bridge under test.

[0115] As an optional implementation, the second deflection difference determination module 702 of the present invention specifically includes:

[0116] The bridge deflection determination unit at the positions of the front and rear sensor groups of the vehicle is used to establish the bridge deflection at the positions of the front and rear sensor groups of the vehicle under the action of the vehicle's gravity when the vehicle travels to each measurement point, based on the principles of structural mechanics.

[0117] The bridge deflection difference calculation unit between the front and rear sensor groups is used to calculate the bridge deflection difference between the front and rear sensor groups based on the bridge deflection at the positions of the front and rear sensor groups of the vehicle.

[0118] As an optional implementation, the first deflection difference determination module 701 of the present invention specifically includes:

[0119] The first distance determination unit is used to measure the distance from each laser range sensor 1 to the bridge surface 4 at each measurement point on the bridge using each laser range sensor 1.

[0120] The horizontal lateral tilt angle measurement unit is used to measure the horizontal lateral tilt angle of the measuring vehicle 3 at each measuring point on the bridge using each tilt angle sensor 2.

[0121] The vertical distance determination unit is used to determine the vertical distance from the bottom of the measuring vehicle 3 to the bridge surface 4 at each measuring point location based on the distance from each laser rangefinder 1 to the bridge surface 4 at each measuring point location and the horizontal lateral tilt angle of the measuring vehicle 3.

[0122] The deflection difference determination unit between two points on the bridge is used to determine the deflection difference between two points on the bridge at each measurement point location based on the vertical distance from the bottom of the measuring vehicle 3 to the bridge deck 4.

[0123] For details of the parts that are the same as in Example 1, please refer to Example 1, and they will not be repeated here.

[0124] Example 3

[0125] The invention also provides a bridge stiffness measurement device based on vehicle-mounted sensors, comprising: two laser rangefinders 1, two tilt sensors 2, and a calculation module; the calculation module is connected to each laser rangefinder 1 and each tilt sensor 2 respectively. The two laser rangefinders 1 are disposed on the lower surface of the measuring vehicle 3, and the two tilt sensors 2 are disposed on the upper surface of the measuring vehicle 3.

[0126] Laser rangefinder 1 is used to measure the distance from each laser rangefinder 1 to the bridge deck 4 at each measurement point on the bridge; tilt sensor 2 is used to measure the horizontal lateral tilt angle of the measuring vehicle 3 at each measurement point on the bridge; the calculation module is used to determine the stiffness of the bridge under test using the method in Example 1.

[0127] As an alternative implementation, the computing module of this invention can be a controller or a host computer. The controller can be any microcontroller or FPGA, and the host computer can be a mobile phone, tablet, desktop computer, etc.

[0128] As an optional implementation, the laser rangefinder 1 and the tilt sensor 2 are arranged correspondingly at the top and bottom.

[0129] For details of the parts that are the same as in Example 1, please refer to Example 1, and they will not be repeated here.

[0130] Example 4

[0131] Taking a simply supported beam bridge with a span of L=30 as an example, the measured bridge stiffness EI=1.25e 10 A schematic diagram of the bridge is shown below. Figure 8 As shown. The bridge cross-sectional dimensions are shown in the diagram. Figure 9 As shown. The vehicle's weight is m = 4.5e. 4 kg. The loads P1 and P2 = P = 220500N, and the distances a1 and a2 from the two sensors to the front and rear wheels, respectively, are both 0.5m.

[0132] x1 = [4.5, 9.5, 14.5, 19.5, 24.5] T ,x2=[8.5,13.5,18.5,23.5,28.5] T ;

[0133] Δd'=[0.00293, 0.0017, 0.00078, 0.00276, 0.00245] T .

[0134] Substituting the measured data into the formula, we get:

[0135] x=[37047675, 21428925, 9624825, 34063575, 29837325] T ,

[0136] Δ=[0.00293, 0.0017, 0.00078, 0.00276, 0.00245] T

[0137]

[0138] According to the formula Solving for EI, we get EI = 1.2491e 10

[0139] The error is

[0140] Through the above engineering examples, the calculation results obtained by the method in this paper are close to the measured stiffness of the bridge, which shows that good technical effects can be achieved after implementing the present invention.

[0141] The above method enables indirect measurement of bridge stiffness EI via vehicle mounting, and the calculation results are processed using the least squares method, improving calculation accuracy. This avoids the cumbersome process of setting up instruments on-site during traditional bridge inspections, significantly improving the efficiency of bridge inspections.

[0142] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for measuring bridge stiffness based on vehicle-mounted sensors, characterized in that, include: Calculate the deflection difference between two points on the bridge at each measurement point location based on the relationship between distance and inclination angle; Based on the principles of structural mechanics, the bridge deflection difference between the front and rear sensor groups is established when the vehicle travels to each measurement point. Let the deflection difference between two points on the bridge at each measurement point be equal to the bridge deflection difference between the front and rear sensor groups at each measurement point. Then, use the least squares method to linearly fit the bridge deflection difference between n front and rear sensor groups to obtain the bridge stiffness equation; where n is a positive integer greater than 1. The positions of the front and rear wheels of the measuring vehicle and two static loads acting perpendicularly to the bridge deck were measured at various measuring points on the bridge. The positions of the front and rear wheels of the measuring vehicle at each measuring point on the bridge and the two static loads acting perpendicularly on the bridge deck are substituted into the bridge stiffness equation to obtain the stiffness of the bridge under test. The deflection difference between any two points on the bridge at each measurement point is set equal to the deflection difference between the preceding and following sensor groups at each measurement point. The least squares method is then used to linearly fit the deflection differences between the n preceding and following sensor groups to obtain the bridge stiffness equation. The specific formula is as follows: ； ， ； ； ； in, The difference in bridge deflection between the front and rear sensor groups at the i-th measurement point on the bridge is represented by L, where L is the bridge length, EI represents the stiffness of the bridge under test, and P1 and P2 represent the forces exerted by the measuring vehicle on the bridge deck, which are equivalently simplified to two static loads acting perpendicularly on the bridge deck. This indicates that the position of the rear wheel of the vehicle is measured at the i-th measurement point on the bridge. This indicates that the position of the front wheel of the vehicle is measured at the i-th measurement point on the bridge, and n represents the total number of measurement points on the bridge. a1 represents the deflection difference between two points on the bridge at the i-th measurement point, a2 represents the distance between the rear sensor group and the rear wheel, and a3 represents the distance between the front sensor group and the front wheel.

2. The bridge stiffness measurement method based on vehicle-mounted sensing according to claim 1, characterized in that, The calculation of the deflection difference between two points on the bridge at each measurement point location based on the relationship between distance and inclination angle specifically includes: The distance from each laser ranging sensor to the bridge deck at each measurement point on the bridge is measured using various laser ranging sensors. The horizontal lateral tilt angle of the measuring vehicle at each measuring point on the bridge is measured using various tilt sensors. The vertical distance from the bottom of the measuring vehicle to the bridge surface at each measuring point is determined based on the distance from each laser ranging sensor to the bridge surface at each measuring point and the horizontal lateral tilt angle of the measuring vehicle. The deflection difference between two points on the bridge at each measurement point is determined by the vertical distance from the bottom of the measuring vehicle to the bridge deck.

3. The bridge stiffness measurement method based on vehicle-mounted sensing according to claim 1, characterized in that, The method of establishing the bridge deflection difference between the front and rear sensor groups when the vehicle travels to each measurement point based on structural mechanics principles specifically includes: Based on the principles of structural mechanics, the bridge deflection at the position of the front sensor group and the position of the rear sensor group are established when the vehicle travels to each measurement point under the action of the vehicle's gravity. The difference in bridge deflection between the front and rear sensor groups is calculated based on the bridge deflection at the locations of the front and rear sensor groups of the vehicle.

4. The bridge stiffness measurement method based on vehicle-mounted sensing according to claim 3, characterized in that, Bridge deflection at the location of the vehicle's rear sensor group at the i-th measurement point on the bridge. The formula is: ； in, This represents the bridge deflection at the location of the vehicle's rear sensor group at the i-th measurement point on the bridge. This represents the bending moment function generated by the bridge when the front wheels are engaged, at the i-th measurement point. Let ds represent the bending moment function at the front wheel position under a unit load when the measuring vehicle is at the i-th measuring point, ds represent the line integral, EI represent the stiffness of the bridge under test, and P1 and P2 represent the forces exerted by the measuring vehicle on the bridge deck, which are equivalently simplified to two static loads acting perpendicularly on the bridge deck. This indicates that the position of the rear wheel of the vehicle is measured at the i-th measurement point on the bridge. This indicates that the position of the front wheel of the vehicle is measured at the i-th measurement point on the bridge, and L represents the length of the bridge.

5. The bridge stiffness measurement method based on vehicle-mounted sensing according to claim 3, characterized in that, Bridge deflection at the location of the vehicle's front sensor group at the i-th measurement point on the bridge. The formula is: ； in, This represents the bridge deflection at the location of the vehicle's front sensor group at the i-th measurement point on the bridge. This represents the bending moment function generated by the bridge when the measuring vehicle is located at the i-th measuring point and the rear wheels are engaged. Let ds represent the bending moment function at the rear wheel position under a unit load when the measuring vehicle is at the i-th measuring point, ds represent the line integral, EI represent the stiffness of the bridge under test, and P1 and P2 represent the forces exerted by the measuring vehicle on the bridge deck, which are equivalently simplified to two static loads acting perpendicularly on the bridge deck. This indicates that the position of the rear wheel of the vehicle is measured at the i-th measurement point on the bridge. This indicates that the position of the front wheel of the vehicle is measured at the i-th measurement point on the bridge, and L represents the length of the bridge.

6. A bridge stiffness measurement system based on vehicle-mounted sensors, characterized in that, The system includes: The first deflection difference determination module is used to calculate the deflection difference between two points on the bridge at each measurement point location based on the relationship between distance and tilt angle. The second deflection difference determination module is used to establish the bridge deflection difference between the front and rear sensor groups when the vehicle travels to each measurement point, based on the principles of structural mechanics. The bridge stiffness equation establishment module is used to set the deflection difference between two points on the bridge at each measurement point to be equal to the bridge deflection difference between the front and rear sensor groups at each measurement point. The least squares method is used to linearly fit the bridge deflection difference between n front and rear sensor groups to obtain the bridge stiffness equation; where n is a positive integer greater than 1. The measurement module is used to measure the positions of the front and rear wheels of the measuring vehicle at various measurement points on the bridge and the two static loads acting perpendicularly on the bridge deck. The module for obtaining the stiffness of the bridge under test is used to input the positions of the front and rear wheels of the measuring vehicle at each measuring point on the bridge and the two static loads acting perpendicularly on the bridge deck into the bridge stiffness equation to obtain the stiffness of the bridge under test. The deflection difference between any two points on the bridge at each measurement point is set equal to the deflection difference between the preceding and following sensor groups at each measurement point. The least squares method is then used to linearly fit the deflection differences between the n preceding and following sensor groups to obtain the bridge stiffness equation. The specific formula is as follows: ； ， ； ； ， in, The difference in bridge deflection between the front and rear sensor groups at the i-th measurement point on the bridge is represented by L, where L is the bridge length, EI represents the stiffness of the bridge under test, and P1 and P2 represent the forces exerted by the measuring vehicle on the bridge deck, which are equivalently simplified to two static loads acting perpendicularly on the bridge deck. This indicates that the position of the rear wheel of the vehicle is measured at the i-th measurement point on the bridge. This indicates that the position of the front wheel of the vehicle is measured at the i-th measurement point on the bridge, and n represents the total number of measurement points on the bridge. a1 represents the deflection difference between two points on the bridge at the i-th measurement point, a2 represents the distance between the rear sensor group and the rear wheel, and a3 represents the distance between the front sensor group and the front wheel.

7. A bridge stiffness measurement system based on vehicle-mounted sensors according to claim 6, characterized in that, The second deflection difference determination module specifically includes: The bridge deflection determination unit at the positions of the front and rear sensor groups of the vehicle is used to establish the bridge deflection at the positions of the front and rear sensor groups of the vehicle under the action of the vehicle's gravity when the vehicle travels to each measurement point, based on the principles of structural mechanics. The bridge deflection difference calculation unit between the front and rear sensor groups is used to calculate the bridge deflection difference between the front and rear sensor groups based on the bridge deflection at the positions of the front and rear sensor groups of the vehicle.

8. A bridge stiffness measurement device based on vehicle-mounted sensors, characterized in that, The device includes: Two laser rangefinders are installed on the bottom of the measuring vehicle to measure the distance from each laser rangefinder to the bridge deck at each measuring point on the bridge. Two tilt sensors are installed on the bottom of the measuring vehicle to measure the horizontal tilt angle of the measuring vehicle at various measuring points on the bridge. The calculation module is connected to each laser rangefinder and each tilt sensor, and is used to determine the stiffness of the bridge under test using the method described in any one of claims 1-5.

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