Bridge pier collision monitoring system

Abstract

The present application relates to the field of sensor monitoring technology, and discloses a pier collision monitoring system, including: a surge monitoring unit and a processing unit connected to the surge monitoring unit; the surge monitoring unit includes a buoy for setting under the water surface around the pier, the buoy has a built-in sensing device, and the sensing device is used to monitor the depth change of the buoy in the water under the influence of surge; the processing unit is used to: obtain a surge signal output by the surge monitoring unit that represents the depth change of the buoy in the water, determine a target positive peak whose amplitude exceeds a preset value from the surge signal, and if the time interval between two adjacent target positive peaks is greater than a time threshold, determine that the pier has been collided. The pier collision monitoring system of the present application has the advantages of high sensitivity, low false alarm rate, and low cost.

Description

Technical Field

[0001] The present application relates to the field of sensor monitoring technology, and in particular to a bridge pier collision monitoring system. Background Art

[0002] With the development of ship science and technology and the expansion of world shipping volume, more and more cross-river and cross-sea bridges are being built. At the same time, the tonnage of ships has increased dramatically, the speed has increased, and shipping has become more and more crowded. When a ship is sailing in a navigable river, improper steering or interference from external factors such as wind, current, and waves can easily cause a ship-bridge collision accident, which can cause damage to the bridge in the lightest case and collapse of the bridge in the worst case. Therefore, ship-bridge collision is a problem that cannot be ignored. In the prior art, various vibration sensors, acceleration sensors, stress sensors, etc. are set on the piers to monitor the collision of ships with bridge piers. However, bridges are large buildings with complex structural components. Especially for extra-large bridges such as cross-sea bridges, strong collision forces are often required to trigger sensor responses, ignoring the impact of continuous small load collisions on the bridge structure, resulting in an increase in the alarm threshold, and the need to layout sensors over a large area, which is costly. In addition, due to the limitations of the sensor's own sensitivity, accuracy, and the interference of the application environment, the monitoring method of laying sensors on the piers has low monitoring accuracy and a high false alarm rate. Summary of the invention

[0003] The embodiment of the present application provides a bridge pier collision monitoring system to solve the defects of the existing monitoring method such as low sensitivity, high false alarm rate and high cost.

[0004] The embodiment of the present application provides a bridge pier collision monitoring system, including: a surge monitoring unit and a processing unit connected to the surge monitoring unit;

[0005] The surge monitoring unit includes a floating ball arranged under the water surface around the bridge pier, the floating ball having a built-in sensing device, the sensing device being used to monitor the depth change of the floating ball in the water under the influence of the surge;

[0006] The processing unit is used to: obtain the surge signal output by the surge monitoring unit that represents the depth change of the float in the water, determine from the surge signal a target positive peak whose amplitude exceeds a preset value, and if the time interval between two adjacent target positive peaks is greater than a time threshold, determine that the bridge pier has been hit.

[0007] Optionally, the processing unit is also used to: if the time interval between two adjacent target positive peaks is greater than a time threshold, then detect the peak-to-valley values ​​of the surge signal between the two adjacent target positive peaks, and use the peak-to-valley values ​​as the surge height difference caused by the collision; and determine the collision intensity level received by the pier based on the time interval between the two adjacent target positive peaks and the surge height difference.

[0008] Optionally, the surge monitoring unit comprises two floating balls, which are arranged on both sides of the pier along the waterway direction, and the distance between the two floating balls is L;

[0009] The processing unit is also used for:

[0010] According to the surge signals monitored by the two buoys, determine the time difference ΔT between the two buoys monitoring the surge generated by the same ship and the average duration T of the two buoys being affected by the surge generated by the same ship;

[0011] Determine the duration T0 and the surge height difference h of the target surge caused by the collision according to the surge signals monitored by the two floats, wherein the target surge is the surge signal between two adjacent target positive peaks whose corresponding time interval is greater than the duration threshold;

[0012] The collision load on the bridge pier is obtained according to the following formula: F = ρSDg ,in, S = hv 0T0, D = L T / (ΔT), v 0 is the average speed of the surge in the water area where the bridge pier is located, ρ is the water density of the water area where the bridge pier is located, g is the acceleration due to gravity.

[0013] Optionally, the sensing device is also used to monitor the horizontal shaking amplitude and direction changes of the buoy in the water; the processing unit is also used to determine whether the bridge pier is hit based on the horizontal shaking amplitude and direction changes of the buoy in the water.

[0014] Optionally, the system further comprises a vibration monitoring unit for installation on the bridge pier, wherein the vibration monitoring unit comprises a sensor; and the processing unit is further used to determine whether the bridge pier is hit according to a change in an output signal of the sensor in the vibration monitoring unit.

[0015] Optionally, when the vibration monitoring unit includes a vibration sensor, the processing unit is specifically used to: detect signal characteristics of the vibration signal output by the vibration sensor; wherein the signal characteristics include: signal noise, intrinsic frequency amplitudes of different frequencies, amplitudes of harmonics, whether new harmonics appear, intrinsic frequency drift, and at least one of harmonic frequency drift; based on changes in the signal characteristics, determine whether the pier has been hit and monitor defects inside the pier.

[0016] Optionally, when the vibration monitoring unit includes an inclination sensor, the processing unit is specifically used to: determine the inclination change of the pier according to the output signal of the inclination sensor; and determine whether the pier is hit and the extent of damage after the collision according to the inclination change of the pier.

[0017] Optionally, when the vibration monitoring unit includes a magnetic field sensor, the magnetic field sensor is used to monitor low-frequency vibration signals and changes in magnetic field strength, and the processing unit is specifically used to: determine whether the bridge pier is hit based on changes in the low-frequency vibration signal monitored by the magnetic field sensor; if it is determined that the bridge pier is hit, determine whether the object that hits the bridge pier is a ship based on changes in the magnetic field strength monitored by the magnetic field sensor.

[0018] Optionally, the system includes a plurality of vibration monitoring units evenly distributed around the side elevation of the pier; the processing unit is further used to determine the direction at which the pier is hit by comparing output signals of sensors in the plurality of vibration monitoring units.

[0019] Optionally, the system further comprises at least one vibration monitoring unit arranged at the connection between the pier and the bridge deck; the processing unit is further used to determine the damage condition of the connection according to the output signal of the sensor in the vibration monitoring unit at the connection.

[0020] The pier collision monitoring system provided in the embodiment of the present application adopts a new pier collision monitoring method, which monitors the surge around the pier by the depth change of the floating ball in the water, and identifies the surge caused by the ship colliding with the pier from the surge signal monitored by the floating ball according to the unique form of the surge generated by the ship colliding with the pier, so as to timely and effectively identify the occurrence of the ship-bridge collision and the time of the collision. Regardless of the size of the ship and the intensity of the collision, as long as the ship collides with the pier, a unique form of target surge will be generated, which will be detected by the system. Therefore, the pier collision monitoring system of the embodiment of the present application has the advantages of high sensitivity, low false alarm rate, and low cost. Furthermore, the data monitored by the surge monitoring unit can be used to estimate the impact intensity level and even obtain the specific collision load, providing more comprehensive reference data for bridge safety monitoring. In addition, by integrating the monitoring data of the vibration monitoring unit on the pier, the accuracy of collision recognition can be further improved, the false alarm rate can be reduced, and the damage assessment and defect monitoring after the collision can be realized at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings introduced below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 A schematic diagram of the structure of a bridge pier collision monitoring system provided in one embodiment of the present application;

[0023] Figure 2 A schematic diagram of a surge signal provided by an embodiment of the present application;

[0024] Figure 3 A schematic diagram of the structure of another bridge pier collision monitoring system provided in one embodiment of the present application;

[0025] Figure 4 A schematic structural diagram of another bridge pier collision monitoring system provided in one embodiment of the present application. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0027] Any number of elements in the drawings is for illustration and not limitation, and any naming is for distinction only and does not have any limiting meaning.

[0028] This is described in detail below in conjunction with the accompanying drawings and specific implementation methods. Although the embodiments of the present application provide method operation steps as shown in the following embodiments or drawings, more or fewer operation steps may be included in the method based on routine or no creative labor, and the embodiments that do not have logical contradictions may be arbitrarily combined with each other. In the steps where there is no necessary causal relationship logically, the execution order of these steps is not limited to the execution order provided in the embodiments of the present application.

[0029] refer to Figure 1 The embodiment of the present application provides a pier collision monitoring system, including a surge monitoring unit and a processing unit 10. The surge monitoring unit includes a float 20 with a built-in sensing device, and the float 20 is arranged under the water surface 904 around the pier 901. The surge generated around the pier 901 will cause the float 20 to float up and down in the water. The built-in sensing device can monitor the depth change of the float 20 in the water under the influence of the surge.

[0030] Most of the wind and waves formed by the natural environment will cause large surges on the water surface, but have little impact on the water surface. The collision between a ship and a bridge pier will cause a large surge under the water surface. Therefore, in the embodiment of the present application, the float can be suspended under the water surface around the bridge pier by adjusting the counterweight of the float and other methods, so as to reduce the effect of the surface surge caused by the natural environment on the float, and ensure that the float is more sensitive to the surge generated when the ship collides with the bridge pier. In specific implementation, the depth position of the float in the still water area can be determined according to the depth of the water area where the pier is located and the draft of the navigable ships in the water area. For example, in a scenario with a water depth of 20 meters, the draft of nearby navigable ships is generally 7 to 14 meters, and the float can be set at a position about 10 meters underwater. Reference Figure 1 The buoys 20 may be disposed on both sides of the bridge pier 901 in the non-navigation area to prevent the ship 903 from touching the buoys 20 when approaching or colliding with the bridge pier 901 .

[0031] In specific implementation, the sensing device in the float can be any one or more sensors that can monitor the depth change of the float in the water, such as pressure sensors, displacement sensors, liquid level meters, etc. The float will float up and down with the underwater surge, and the sensing device built into the float will monitor the depth change of the float. The depth change of the float reflects the amplitude change of the surge. Therefore, the surge signal collected by the built-in sensing device can represent the depth change of the float in the water and the amplitude change of the surge. Figure 1 The float 20 can be connected to the pier 901 through a connecting line. The functions of the connecting line include mechanical dragging and electrical signal transmission to ensure that the float 20 can only float up and down within a certain radius area around the pier 901, and the surge signal collected by the built-in sensing device is transmitted to the processing unit 10 on the pier 901 through the connecting line.

[0032] Figure 2 This is a surge signal detected by the float. Figure 2 The vertical axis of the surge signal shown in FIG. 1 represents the depth, so the positive peak value in the surge signal actually corresponds to the trough of the surge, and the negative peak value in the surge signal actually corresponds to the peak of the surge. Figure 2 In the surge signal shown, the signal from one positive peak to the next positive peak corresponds to a surge, for example, the signal in the time period t1 to t2 corresponds to a surge, and the time interval from one positive peak to the next positive peak corresponds to the duration of a surge.

[0033] Below Figure 2 Taking the surge signal shown in the figure as an example, the process before and after the ship hits the bridge pier is explained. When the ship approaches the bridge pier, a surge will be formed near the pier. The closer the ship is to the pier, the larger the surge will be, and the duration of each surge will be relatively longer. Figure 2Taking the surge signal shown in the figure as an example, the time period t0~t1 corresponds to the process of the ship approaching the bridge pier. Compared with the signal before t0, the amplitude of the surge signal monitored in the time period t0~t1 gradually increases and the duration of each surge increases. The ship collides with the bridge pier and instantly displaces the water between the ship and the bridge pier. The displaced water flow forms a large surge, forcing the depth of the float to reach the maximum, which corresponds to Figure 2 At time t1. The reaction force generated by the collision then forces the ship to move away from the bridge pier, and a large amount of water flows back between the bridge pier and the ship, thus forming a large surge at the bridge pier, which is the target surge caused by the collision, corresponding to Figure 2 In the time period t1~t2, the amplitude and duration of the target surge generated by the collision are obviously greater than those of the ordinary surge. The collision causes a surge to surge back and forth between the bridge pier and the ship, which gradually calms down after a period of time until the ship completely passes the bridge pier. The above process corresponds to Figure 2 The surge amplitude before t0 and after t3 is small and the duration of each surge is short, which can be considered to be caused by normal water flow fluctuations. The time period from t0 to t3 can be considered as the process of the ship passing under the bridge.

[0034] To this end, the processing unit 10 is used to: obtain a surge signal output by the surge monitoring unit that represents the depth change of the float in the water, determine a target positive peak value whose amplitude exceeds a preset value from the surge signal, and if the time interval between two adjacent target positive peaks is greater than a time threshold, it is determined that the bridge pier has been hit.

[0035] Among them, the preset value and the duration threshold can be determined based on the measured data around the bridge piers. The values ​​in different application scenarios may be different, so the embodiments of the present application are not limited. For example, the preset value is determined based on the amplitude of the surge monitored when no ship passes through the bridge to filter out the peak value generated by environmental interference and the peak value generated by smaller surges; based on the measured surge signal, the duration of each surge before and after the collision is counted, and the duration threshold should not be less than the maximum value of these statistical data.

[0036] From the previous analysis, we know that the amplitude and duration of the surge caused by the ship colliding with the bridge pier are obviously greater than the ordinary surge. Therefore, we can first filter out the positive peak whose amplitude exceeds the preset value from the surge signal as the target positive peak; then detect the time interval between any two adjacent target positive peaks, and the signal between the two adjacent target positive peaks with a time interval greater than the duration threshold corresponds to the target surge caused by the collision; when the target surge is detected, it indicates that the bridge pier has been collided, and the moment corresponding to the first target positive peak of the two adjacent target positive peaks used to determine the target surge is the moment of the ship-bridge collision.

[0037] The pier collision monitoring system of the embodiment of the present application adopts a new pier collision monitoring method, which monitors the surge around the pier by the change of the depth of the float in the water, and identifies the surge caused by the ship collision with the pier from the surge signal monitored by the float based on the unique shape of the surge generated by the ship collision with the pier, so as to timely and effectively identify the occurrence of the ship-bridge collision and the time of the collision. Regardless of the size of the ship and the intensity of the collision, as long as the ship collides with the pier, a unique shape of target surge will be generated, which will be detected by the system. Therefore, compared with the solution using sensors such as vibration sensors, acceleration sensors, and stress sensors, the pier collision monitoring system of the embodiment of the present application has the advantages of high sensitivity, low false alarm rate, and low cost.

[0038] The existing technology uses sensors for monitoring, which is limited by the sensitivity, accuracy and interference of the application environment. It can only monitor whether a collision occurs, but it is difficult to monitor the intensity of the collision. In a further embodiment of the present application, the data monitored by the surge monitoring unit can also be used to estimate the impact intensity level when the ship-bridge collision occurs, and even obtain the specific collision load.

[0039] The force of a ship hitting a bridge pier is the wave in the water carrying the ship to hit it. After hitting the bridge pier, the ship leaves the pier, which will also form a reverse surge. During the entire ship-bridge collision process, the length of time the pier is subjected to force and the magnitude of the force are closely related to the amplitude of the surge and the duration of the surge. The larger the amplitude of the surge caused by the collision and the longer the duration of the surge, the greater the impact force on the pier.

[0040] To this end, in a possible implementation, the processing unit is also used to: if the time interval between two adjacent target positive peaks is greater than a time threshold, then detect the peak-to-valley values ​​of the surge signal between the two adjacent target positive peaks, and use the peak-to-valley values ​​as the surge height difference caused by the collision; determine the collision intensity level received by the bridge pier based on the time interval and the surge height difference between the two adjacent target positive peaks.

[0041] by Figure 2 For example, the target surge caused by the collision corresponds to the surge signal in the time period of t1~t2. The duration of the target surge caused by the collision is T0=t2~t1. The peak-to-valley value of the surge signal in the time period of t1~t2 is detected. The peak-to-valley value is the surge height difference of the target surge caused by the collision. h , surge height difference h The larger the duration T0 is, the greater the surge caused by the collision is, which in turn indicates that the impact on the bridge pier is more severe.

[0042] In specific implementation, the surge height difference can be hThe product of the duration T0 and the impact strength level of the bridge pier is used to measure the impact strength level. In practical applications, the product can be determined in advance based on experimental data. h The relationship between T0 and the impact force on the bridge pier is obtained through experiments. The above relationship is only a rough estimate of the degree of collision, rather than a more accurate value. Therefore, it can be divided into several different collision intensity levels, such as slight, moderate, severe, and extremely severe. Each collision intensity level corresponds to a different range of products. h T0, the higher the collision intensity level, the corresponding product h The larger the value of T0 is.

[0043] Therefore, the bridge pier collision monitoring system provided in the embodiment of the present application can evaluate the impact intensity of the ship-bridge collision by detecting the surge height difference and duration, so as to provide more comprehensive monitoring data.

[0044] In another possible implementation, the surge monitoring unit may include two floats (eg Figure 3 The floating balls 201 and 202 are arranged on both sides of the pier 901 along the channel direction, and the distance between the two floating balls is L , the specific structure is as follows Figure 3 It should be noted that the float is not fixed. In order to facilitate subsequent calculations, the distance between the two floats is L A fixed value can be taken, and the specific value can be determined according to the installation position of the two floats.

[0045] based on Figure 3 The surge signals collected by the two buoys shown can obtain relatively accurate collision loads. To this end, the processing unit is also used to: determine the time difference ΔT between the two buoys monitoring the surge generated by the same ship and the average duration T of the two buoys being affected by the surge generated by the same ship based on the surge signals monitored by the two buoys; determine the duration T0 of the target surge caused by the collision and the surge height difference based on the surge signals monitored by the two buoys h , where the target surge corresponds to the surge signal between two adjacent target positive peaks whose time interval is greater than the duration threshold; the collision load on the bridge pier is obtained according to the following formula:

[0046] F = ρSDg ,

[0047] in, S = hv 0 T 0, D = L T / (ΔT), v 0 is the average speed of the surge in the water area where the bridge pier is located, ρ is the water density of the water area where the bridge pier is located, gis the acceleration due to gravity. v 0 and ρ It can be determined through measured data.

[0048] refer to Figure 3 , the float 201 outputs the first surge signal, and the float 202 outputs the second surge signal. The surges formed by the same ship 903 detected by the float 201 and the float 202 should have almost the same shape. Check in sequence whether the time interval between two adjacent positive peaks in the first surge signal is greater than the interval threshold, and record the surge signal between two adjacent positive peaks with a time interval greater than the interval threshold as a valid surge, and record the surge signal between two adjacent positive peaks with a time interval not greater than the interval threshold as an invalid surge. Record the time t corresponding to the first valid surge 0,1 ; Then continue to detect time t 0,1 Each surge in the first surge signal is a valid surge or an invalid surge. In order to improve the monitoring accuracy, when a preset number of invalid surges are detected continuously, the detection is stopped and the time t corresponding to the last valid surge is recorded. 3,1 The time period during which the bridge pier is affected by the surge generated by the ship is t 0,1 ~t 3,1 The preset number can be determined according to the actual situation, for example, the preset number can be 1, 2, 3, etc., which is not limited in the present embodiment. In the same way, the time period during which the bridge pier is affected by the surge generated by the ship is determined from the second surge signal as t 0,2 ~t 3,2 Therefore, the time difference between the buoy 201 and the buoy 202 detecting the surge generated by the same ship is ΔT=|t 0,1 -t 0,2 |, average action time T=(|t 3,1 -t 0,1 |+|t 3,2 -t 0,2 |) / 2. Based on the method of determining the duration of the target surge and the surge height difference provided in the above embodiments, the duration T of the target surge caused by the collision is determined from the first surge signal. 0,1 and surge height difference h 1. Determine the duration T of the target surge caused by the collision from the second surge signal 0,2 and surge height difference h 2, then the duration of the target surge is T0=(T 0,1 +T 0,2 ) / 2, surge height difference h= ( h 1+ h 2) / 2.

[0049] The formula for calculating the collision load isD represents the length of the ship, assuming Figure 3 Ship 903 in the figure is sailing to the left at a speed of v ,but v=L / (ΔT), the time required for the ship 903 to pass through the bridge pier 901 is T'= D / v , when the ship 903 passes through the bridge pier 901, a surge is generated, so T'≈T. The above relationship can be used to obtain the formula D = L T / (ΔT), used to estimate the length of the ship. S = hv 0 T 0, so S represents the cross-sectional area of ​​the target surge formed, ρSDg It means the length is D The total weight of the surge caused by the collision of the ship passing through the bridge pier. The surge is caused by the collision between the ship and the bridge. The size of the surge is related to the impact force of the collision between the ship and the bridge. Therefore, it can be ρSDg To describe the impact load on the bridge pier F .

[0050] Therefore, the pier collision monitoring system provided in the embodiment of the present application can estimate the collision load on the pier through the surge signal monitored by two buoys when a ship passes through the pier, thereby providing more comprehensive reference data for bridge safety monitoring.

[0051] On the basis of any of the above-mentioned embodiments, the sensing device is also used to monitor the horizontal shaking amplitude and direction change of the float in the water. In specific implementation, the sensing device may include a three-axis displacement sensor for monitoring low-frequency vibrations, etc., to monitor the horizontal shaking amplitude of the float in the water. The sensing device may also include a magnetic field type direction sensor to monitor the direction change of the float in the water. When a large ship with a large displacement and a wide width passes through a bridge pier, a large surge will be generated even if no collision occurs, but at this time, the horizontal shaking amplitude and direction change of the float in the water near the bridge pier are relatively small. In the case of a ship colliding with a bridge pier, the float will be very close to the ship, and the horizontal shaking amplitude and direction of the float will change greatly, such as a horizontal displacement of more than 2 meters for the float, and a rotation of 180 or 360 degrees for the float.

[0052] To this end, the processing unit is further used to determine whether the bridge pier has been hit according to the horizontal shaking amplitude and direction change of the floating ball in the water. Specifically, if the horizontal shaking amplitude of the floating ball in the water is greater than the shaking amplitude threshold and / or the direction change is greater than the direction change threshold, it is determined that the bridge pier has been hit, otherwise it is determined that the bridge pier has not been hit.

[0053] Furthermore, the monitoring results of the target surge, the horizontal sway amplitude and the direction change of the buoy can be integrated to comprehensively judge whether a ship-bridge collision has occurred. For example, if the target surge, the horizontal sway amplitude of the buoy is greater than the sway amplitude threshold, and the direction change of the buoy is greater than the direction change threshold, it is determined that a ship-bridge collision has occurred; otherwise, it is determined that no ship-bridge collision has occurred.

[0054] These cheap, simple and reliable sensors built into the float can help confirm whether a collision has actually occurred between the ship and the bridge pier, thereby improving recognition accuracy and reducing the false alarm rate.

[0055] On the basis of any of the above-mentioned embodiments, the pier collision monitoring system provided in the embodiment of the present application further includes a vibration monitoring unit for installation on the pier, and the vibration monitoring unit includes at least one sensor selected from a vibration sensor, an inclination sensor, and a magnetic field sensor. The vibration monitoring unit is connected to the processing unit, and the processing unit is further used to determine whether the pier is hit according to the change of the output signal of the sensor in the vibration monitoring unit.

[0056] When a ship collides with a bridge pier, it will cause the pier to vibrate or deform. Vibration sensors, inclination sensors and magnetic field sensors can monitor these changes. Therefore, by comparing the difference in the output signals of the sensors before and after the collision, it is possible to detect whether the bridge pier has been hit.

[0057] The processing unit can integrate the monitoring data of the vibration monitoring unit and the surge monitoring unit to improve the accuracy of collision recognition and further reduce the false alarm rate.

[0058] The vibration sensor in the vibration monitoring unit may be a three-axis vibration sensor, the inclination sensor may be a three-axis inclination sensor, and the magnetic field sensor may be a three-axis magnetic field sensor.

[0059] In specific implementation, when the vibration monitoring unit includes a vibration sensor, the processing unit is specifically used to: detect the signal characteristics of the vibration signal output by the vibration sensor; wherein the signal characteristics include: signal noise, intrinsic frequency amplitudes of different frequencies, amplitudes of harmonics, whether new harmonics appear, intrinsic frequency drift, at least one of harmonic frequency drift; based on changes in signal characteristics, determine whether the pier is hit and monitor defects inside the pier.

[0060] Vibration sensors are used to detect high-frequency vibrations of bridge piers. Since the foundation under each bridge pier and the bridge deck load above are specific, the structure, material, size, underground support environment, bridge deck load, etc. of the bridge piers that determine the eigenfrequency of each bridge pier are different. The vibration frequency span of the system is relatively large, and there will be more high-order harmonics and larger amplitudes after the collision. Among them, high-order harmonics refer to harmonics higher than the third harmonic, the fifth harmonic, the seventh harmonic, etc., and high-order harmonics often mean defects such as cracks inside or on the surface of the bridge pier. Therefore, when a collision occurs, the noise of the vibration sensor increases, the amplitude of the eigenfrequency of different frequencies increases, the amplitude of the harmonics increases, more new harmonics appear, the eigenfrequency drifts, the harmonic frequency drifts, etc. The greater the collision intensity, the greater the change amplitude of each signal feature. Therefore, a corresponding judgment threshold can be preset for each signal feature. If the signal feature of the vibration signal output by the vibration sensor changes as described above and the change exceeds the corresponding judgment threshold, it is determined that the bridge pier has been collided. Furthermore, when a collision occurs, the collision intensity level can be assisted in judging based on the change amplitude of each signal feature of the vibration signal.

[0061] Factors such as ship-bridge collision and aging of bridge structures can cause cracks and other defects inside or on the surface of bridge piers. Vibration sensors can be used to monitor bridge pier defects over a long period of time. When new harmonics appear in the vibration signal or when intrinsic frequency drift or harmonic frequency drift occurs, it means that cracks and other defects have occurred inside or on the surface of the bridge pier.

[0062] Vibration sensors can effectively identify the occurrence of ship-bridge collisions and internal defects after collisions, and achieve long-term defect monitoring.

[0063] In specific implementation, when the vibration monitoring unit includes a tilt sensor, the processing unit is specifically used to: determine the tilt change of the bridge pier according to the output signal of the tilt sensor; determine whether the bridge pier has been hit according to the tilt change of the bridge pier. The tilt sensor can monitor the low-frequency vibration caused by the collision, and the tilt sensor converts the low-frequency vibration into a tilt output. When the monitored tilt change is greater than the tilt threshold, it is determined that the bridge pier has been hit. Among them, the tilt threshold can be determined based on experimental data and experience, and the embodiments of the present application are not limited. When a collision occurs, the greater the monitored tilt change and the higher the frequency of change, the greater the impact force of the collision. Therefore, the collision intensity level can also be judged based on the tilt change.

[0064] Furthermore, the processing unit is also used to determine the degree of damage to the bridge pier after the collision according to the change in the inclination of the bridge pier. After the collision, the difference in the inclination of the bridge pier before and after the collision is determined by the inclination sensor, and the degree of damage after the collision is determined according to the inclination difference. The greater the inclination difference, the greater the degree of damage to the bridge pier. A collision with a smaller intensity is likely not to change the inclination of the bridge pier before and after the collision, while a collision with a larger intensity may cause irreversible structural damage to the bridge pier, resulting in a significant change in the inclination of the bridge pier after the collision. If the inclination of the bridge pier after the collision is greater than the danger threshold, an alarm process can be directly performed.

[0065] In a specific implementation, when the vibration monitoring unit includes a magnetic field sensor, the processing unit is further used to: if it is determined that the bridge pier is hit, determine whether the object that hits the bridge pier is a ship based on the change in magnetic field intensity monitored by the magnetic field sensor. The magnetic field sensor can monitor whether most ships made of steel materials have experienced changes in magnetic field during the collision process, thereby further confirming that the collision was caused by a ship.

[0066] In a specific implementation, the magnetic field sensor can monitor not only the change in magnetic field strength, but also the low-frequency vibration signal caused by the collision between the ship and the bridge, so as to determine whether the bridge pier has been hit. To this end, when the vibration monitoring unit includes a magnetic field sensor, the processing unit can also be used to: determine whether the bridge pier has been hit according to the change in the low-frequency vibration signal monitored by the magnetic field sensor.

[0067] The vibration monitoring unit can integrate the monitoring data of the above multiple sensors to improve the accuracy of collision recognition, further reduce the false alarm rate, and realize damage assessment and defect monitoring after the collision. For example, if it is determined that the bridge pier has been hit based on the monitoring data of all sensors or at least two sensors in the vibration monitoring unit, then the bridge pier is considered to have been hit, otherwise it is considered that the bridge pier has not been hit.

[0068] In a possible implementation, the monitoring results of the vibration monitoring unit and the surge monitoring unit can be integrated to further determine whether the bridge pier is actually hit, further improve the recognition accuracy, and reduce the false alarm rate. For example, if the monitoring data of the vibration monitoring unit and the surge monitoring unit both determine that the bridge pier is hit, then the bridge pier is determined to be hit, otherwise it is determined that the bridge pier is not hit.

[0069] On the basis of any of the above-mentioned embodiments, the pier collision monitoring system provided in the embodiment of the present application includes a plurality of vibration monitoring units, and the plurality of vibration monitoring units are evenly distributed around the side elevation of the pier. The processing unit is also used to: determine the direction in which the pier is hit by comparing the output signals of the sensors in the plurality of vibration monitoring units. Among them, the direction corresponding to the sensor with the largest output signal change is the direction in which the pier is hit.

[0070] refer to Figure 4, four vibration monitoring units 30 can be evenly arranged around the side elevation of the bridge pier 901 (one vibration monitoring unit 30 is on the back of the bridge pier 901 and the other is not on the back of the bridge pier 901). Figure 4 ), the signal change output by the vibration monitoring unit closest to the collision position should be the largest. The output signals of the sensors in the vibration monitoring units in the four directions before and after the collision are compared respectively. The direction corresponding to the sensor with the largest output signal change is the direction where the bridge pier is hit. Since the vibration monitoring unit may include multiple different types of sensors, what needs to be compared are the output signals of sensors of the same type in different directions. For example, the direction where the bridge pier is hit is determined by comparing the output signals of vibration sensors in four directions, the direction where the bridge pier is hit is determined by comparing the output signals of inclination sensors in four directions, and the direction where the bridge pier is hit is determined by comparing the output signals of magnetic field sensors in four directions.

[0071] By comparing the output signals of multiple vibration monitoring units in different directions, it is possible to more accurately determine which position of the bridge pier has been hit.

[0072] Further, refer to Figure 4 The bridge pier collision monitoring system provided in the embodiment of the present application further includes at least one vibration monitoring unit 30 disposed at the connection between the bridge pier 901 and the bridge deck 902. The processing unit is also used to determine the damage condition of the connection according to the output signal of the sensor in the vibration monitoring unit at the connection.

[0073] The connection between the bridge pier and the bridge deck is a relatively weak structural position. If the bridge pier is hit hard, it may generate a large tangential force that destroys the connection between the bridge pier and the bridge deck. Therefore, 1~2 vibration monitoring units can be fixed on the steel structure of the bridge pier supporting the bridge deck. By comparing the signal difference of the vibration monitoring unit at this position before and after the collision, the damage of the connection between the bridge pier and the bridge deck can be determined, and the connection between the bridge pier and the bridge deck can be focused on. The specific monitoring method refers to the previous description of the vibration monitoring unit and its internal sensor, which will not be repeated here.

[0074] The above embodiments are only used to introduce the technical solutions of the present application in detail, but the description of the above embodiments is only used to help understand the methods of the embodiments of the present application and should not be understood as limiting the embodiments of the present application. Any changes or substitutions that can be easily thought of by technicians in this technical field should be included in the protection scope of the embodiments of the present application.

Claims

1. A bridge pier collision monitoring system, characterized in that: include: A surge monitoring unit and a processing unit connected to the surge monitoring unit; The surge monitoring unit includes a floating ball arranged under the water surface around the bridge pier, the floating ball having a built-in sensing device, the sensing device being used to monitor the depth change of the floating ball in the water under the influence of the surge; The processing unit is used to: obtain the surge signal output by the surge monitoring unit and representing the depth change of the buoy in the water, determine the target positive peak whose amplitude exceeds the preset value from the surge signal, and if the time interval between two adjacent target positive peaks is greater than the time length threshold, determine that the bridge pier is hit; The processing unit is also used for: If the time interval between two adjacent target positive peaks is greater than the duration threshold, the peak-to-valley value of the surge signal between the two adjacent target positive peaks is detected, and the peak-to-valley value is used as the surge height difference caused by the collision; Determining the collision intensity level of the bridge pier according to the time interval between the two adjacent target positive peaks and the surge height difference; The surge monitoring unit includes two floating balls, which are arranged on both sides of the pier along the waterway direction, and the distance between the two floating balls is L ; The processing unit is also used for: According to the surge signals monitored by the two buoys, determine the time difference ΔT between the two buoys monitoring the surge generated by the same ship and the average duration T of the two buoys being affected by the surge generated by the same ship; According to the surge signals detected by the two floats, the duration T0 of the target surge caused by the collision and the surge height difference are determined. h , wherein the target surge is a surge signal between two adjacent target positive peaks whose corresponding time interval is greater than a duration threshold; The collision load on the bridge pier is obtained according to the following formula: F = ρSDg ， in, S = hv 0T0, D = L T / (ΔT), v 0 is the average speed of the surge in the water area where the bridge pier is located, ρ is the water density of the water area where the bridge pier is located, g is the acceleration due to gravity.

2. The system according to claim 1, characterized in that The sensing device is also used to monitor the horizontal shaking amplitude and direction changes of the floating ball in the water; The processing unit is also used to determine whether the bridge pier is hit according to the horizontal shaking amplitude and direction change of the floating ball in the water.

3. The system according to claim 1 or 2, characterized in that: The system further comprises a vibration monitoring unit for installation on the pier, the vibration monitoring unit comprising a sensor; The processing unit is further used to determine whether the bridge pier is hit according to changes in output signals of sensors in the vibration monitoring unit.

4. The system according to claim 3, characterized in that When the vibration monitoring unit includes a vibration sensor, the processing unit is specifically configured to: Detecting signal characteristics of the vibration signal output by the vibration sensor; wherein the signal characteristics include: at least one of signal noise, eigenfrequency amplitudes of different frequencies, amplitudes of harmonics, whether new harmonics appear, eigenfrequency drift, and harmonic frequency drift; According to the change of the signal characteristics, it is determined whether the bridge pier is hit and the defects inside the bridge pier are monitored.

5. The system according to claim 3, characterized in that When the vibration monitoring unit includes a tilt sensor, the processing unit is specifically configured to: Determining the inclination change of the pier according to the output signal of the inclination sensor; Whether the bridge pier is hit and the extent of damage after the collision are determined based on the change in the inclination angle of the bridge pier.

6. The system according to claim 3, characterized in that When the vibration monitoring unit includes a magnetic field sensor, the magnetic field sensor is used to monitor the low-frequency vibration signal and the change of the magnetic field intensity, and the processing unit is specifically used to: Determining whether the bridge pier is hit according to changes in the low-frequency vibration signal monitored by the magnetic field sensor; If it is determined that the bridge pier is hit, then it is determined whether the object hitting the bridge pier is a ship based on the change in magnetic field intensity monitored by the magnetic field sensor.

7. The system according to claim 3, characterized in that The system comprises a plurality of vibration monitoring units evenly distributed around the side elevation of the pier; The processing unit is also used to determine the direction where the bridge pier is hit by comparing the output signals of the sensors in the plurality of vibration monitoring units.

8. The system according to claim 7, characterized in that The system further comprises at least one vibration monitoring unit disposed at a connection between the pier and the bridge deck; The processing unit is further used to determine the damage condition of the connection according to the output signal of the sensor in the vibration monitoring unit of the connection.

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