JP7579532B2 - Bridge monitoring device, bridge monitoring system, bridge monitoring method, and bridge monitoring program - Google Patents

Description

The present invention relates to a bridge monitoring device, a bridge monitoring system, a bridge monitoring method, and a bridge monitoring program, and in particular to a bridge monitoring device, a bridge monitoring system, a bridge monitoring method, and a bridge monitoring program that can monitor the inclination of a bridge from a remote location.

When monitoring bridges that make up roads, conventionally, a surveillance camera would capture an image of a specific position on the bridge being monitored, and the displacement of the specific position on the bridge would be measured based on the surveillance camera's captured data to detect any abnormalities in the bridge (see Patent Document 1). However, the method of monitoring bridges using surveillance cameras has the problem that the surveillance cameras consume a lot of power because they are constantly running.

A method was therefore devised to monitor the structure by installing an inclinometer on the bridge to be monitored and measuring the change in the inclination angle (see Patent Document 2). However, even if an attempt was made to monitor the structure by measuring the inclination angle of the structure, there were cases in which the influence of vibrations caused by vehicles, etc. was so great that it was not possible to reliably measure the amount of change in the structure's inclination angle.

JP 2015-158112 A JP 2020-16115 A

Therefore, the present disclosure provides a bridge monitoring device, a bridge monitoring system, a bridge monitoring method, and a bridge monitoring program that can reliably detect the inclination of a monitored bridge even when it is affected by vibrations or the like, and monitor the bridge for abnormalities.

That is, the bridge monitoring device according to the first aspect includes an abutment portion that abuts against the bridge, a housing portion connected to the abutment portion via vibration-proofing material, an inclination detection sensor portion that is housed inside the housing portion and detects the inclination of the bridge that is abutted against the abutment portion via the abutment portion, and a detection information transmission portion that transmits the detection information detected by the inclination detection sensor portion via wireless communication.

In a second aspect, in the bridge monitoring device according to the first aspect, the tilt detection sensor unit may be fixed to the housing unit via another vibration-isolating material different from the vibration-isolating material.

In a third aspect, in the bridge monitoring device according to the first or second aspect, the vibration-proofing material may comprise a gel-like material, and vibrations may be reduced by the gel-like material.

In a fourth aspect, in the bridge monitoring device according to the first to third aspects, the bridge may have a portion made of steel, and the contact portion may have a magnet on a surface portion that contacts the portion made of steel.

In a fifth aspect, in the bridge monitoring device according to the fourth aspect, the housing may be magnetically shielded to block the magnetic force of the magnet provided in the contact portion.

In a sixth aspect, in the bridge monitoring device according to the first to fifth aspects, the inclination detection sensor unit may detect the inclination of the bridge using a two-axis inclinometer.

The seventh aspect is a bridge monitoring system that monitors a bridge using a bridge monitoring device according to any one of the first to sixth aspects, and includes a monitoring target setting unit that accepts settings for a bridge to be monitored by the bridge monitoring system, an inclination information acquisition unit that acquires detection information detected by the bridge monitoring device via wireless communication, an inclination information determination unit that determines whether or not the amount of change in the inclination angle of the bridge has exceeded a predetermined threshold based on the detection information acquired by the inclination information acquisition unit, and a notification unit that notifies a user of an abnormality in the bridge when the inclination information determination unit determines that the amount of change in the inclination angle of the bridge has exceeded the predetermined threshold.

The eighth aspect is a bridge monitoring method for monitoring a bridge using a bridge monitoring device according to any one of the first to sixth aspects, which includes a monitoring target setting step for accepting settings for a bridge to be monitored by the bridge monitoring method, a tilt information acquisition step for acquiring detection information detected by the bridge monitoring device via wireless communication, a tilt information determination step for determining whether or not a change in the tilt angle of the bridge has exceeded a predetermined threshold based on the detection information acquired by the tilt information acquisition step, and a notification step for notifying a user of an abnormality in the bridge when the tilt information determination step determines that the change in the tilt angle of the bridge has exceeded the predetermined threshold.

The ninth aspect is a bridge monitoring program for monitoring a bridge using a bridge monitoring device according to any one of the first to sixth aspects, which has a computer used in the bridge monitoring system realize a monitoring target setting function for accepting settings for a bridge to be monitored, an inclination information acquisition function for acquiring detection information detected by the bridge monitoring device via wireless communication, an inclination information determination function for determining whether or not the amount of change in the inclination angle of the bridge has exceeded a predetermined threshold based on the detection information acquired by the inclination information acquisition function, and a notification function for notifying a user of an abnormality in the bridge when the inclination information determination function determines that the amount of change in the inclination angle of the bridge has exceeded the predetermined threshold.

The bridge monitoring device, bridge monitoring system, bridge monitoring method, and bridge monitoring program disclosed herein can reliably detect the inclination of the monitored bridge even if it is affected by vibrations or other factors, and can monitor the bridge for abnormalities.

1 is a diagram showing an overall configuration including a bridge monitoring device and a bridge monitoring system according to an embodiment of the present invention. FIG. 2 is a diagram showing a state in which a bridge monitoring device is installed on a bridge. 3A, 3B, and 3C show the appearance of a bridge monitoring device, with FIG. 3A and 3B show the inside of a bridge monitoring device, in which FIG. 3A and 3B show cross sections of a bridge monitoring device, where FIG. FIG. 4 is an enlarged view showing the vibration-proof material and its surroundings in the housing portion. FIG. 2 is a diagram showing an example of a functional block diagram of a bridge monitoring device. 1A and 1B show the inside of the container, where FIG. FIG. 4 is an enlarged view showing the vibration-proof material and its surroundings in the container. FIG. 1 is a block diagram showing the hardware configuration of a bridge monitoring system. FIG. 1 is a block diagram showing the software configuration of a bridge monitoring system. Flowchart of the bridge monitoring program.

An embodiment of a bridge monitoring device 10 and a bridge monitoring system 12 according to the present disclosure will be described with reference to Figs. 1 to 11. The overall configuration including the bridge monitoring device 10 and the bridge monitoring system 12 will be described with reference to Fig. 1. Fig. 1 shows the overall configuration including the bridge monitoring device 10 and the bridge monitoring system 12 according to this embodiment.

The bridge monitoring device 10 is installed on the bridge 13 to be monitored. The inclination of the bridge 13 detected by the bridge monitoring device 10 is transmitted to the bridge monitoring system 12 via LPWA (Low Power Wide Area) wireless communication.

As described below, the bridge monitoring device 10 includes an inclination detection sensor unit 28, a detection information transmission unit 29, a control unit 40, a power supply unit 31, and a memory unit 32. The bridge monitoring device 10 detects the inclination of the bridge 13 using the inclination detection sensor unit 28. The inclination of the bridge 13 detected by the bridge monitoring device 10 may include both the x and y components of the gravitational acceleration, and the inclination angle of the bridge 13 calculated based on the x and y components of the gravitational acceleration.

The bridge monitoring system 12 is a system operated by a user, and is connected to the LPWA platform 14 via wired/wireless communication. The platform refers to the infrastructure equipment required to operate the LPWA, such as base station equipment. The bridge monitoring system 12 may be connected to the LPWA platform 14 via wired/wireless communication via the Internet 14a.

With reference to Figure 2, the state in which the bridge monitoring device 10 is installed on a bridge 13 will be described. Figure 2 shows the state in which the bridge monitoring device 10 is installed on a bridge 13. The bridge 13 comprises a bridge body 15 as a superstructure and a pier 16 as a substructure. The bridge 13 is constructed by connecting two or more bridge bodies 15, with the pier 16 supporting the connecting parts between the bridge bodies 15. Furthermore, the bridge 13 comprises a support 17 installed between the superstructure and the substructure.

When a bridge 13 is subjected to an earthquake, or when the bridge 13 deteriorates over time, the bridge body 15 or pier 16 that constitutes the bridge 13 may tilt. One bridge monitoring device 10 is installed for each bridge body 15 and one for each pier 16. The bridge monitoring device 10 installed on the bridge body 15 detects the tilt of the bridge body 15 by tilting together with the bridge body 15. The bridge monitoring device 10 installed on the pier 16 detects the tilt of the pier 16 by tilting together with the pier 16.

As shown in FIG. 3, the bridge monitoring device 10 includes a magnet holding plate 22 equipped with a permanent magnet 18. The permanent magnet 18 is attached to the magnet holding plate 22 with both sides sandwiched between the yoke portion 18a. The rear portions of the permanent magnet 18 and the yoke portion 18a form the abutment portion 19 of the bridge monitoring device 10.

The bridge monitoring device 10 is attached to the steel parts of the bridge body 15 or pier 16, or to the steel parts of the bridge body 15 and pier 16, by the attractive force of the permanent magnet 18. The abutment part 19 of the bridge monitoring device 10 abuts against the steel parts of the bridge body 15 or pier 16.

The configuration of the bridge monitoring device 10 will be described with reference to Figures 3 to 8. Figure 3 shows the exterior of the bridge monitoring device 10, with (a) being a side view, (b) being a front view, and (c) being a bottom view. Figure 4 shows the interior of the bridge monitoring device 10, with (a) being a side view and (b) being a front view. Figure 4 shows the bridge monitoring device 10 with the side shield plate portion 23 removed.

Figure 5 shows a cross section of the bridge monitoring device 10, with (a) being a side view and (b) being a front view. Figure 5(b) shows a cross section taken along the line A-A in Figure 5(a). Figure 6 shows an enlarged view of the vibration-proof material 27 and its surroundings in the housing unit 20. Figure 7 shows an example of a functional block diagram of the bridge monitoring device 10. Figure 8 shows the inside of the container 30, with (a) being a front view and (b) being a bottom view.

As shown in FIG. 3, the bridge monitoring device 10 comprises a roughly rectangular parallelepiped housing unit 20 and an antenna unit 21. The housing unit 20 is made of magnetic metal and has a magnetic shielding function that blocks the magnetic force of the permanent magnet 18 from penetrating into the interior. The antenna unit 21 carries the hollow wire of the detection information transmission unit 29.

As shown in FIG. 3, the housing 20 includes a side shield plate 23, a front shield plate 24, a top shield plate 25, and a bottom shield plate 26. As shown in FIG. 5(a), the back surface of the housing 20 is covered by a magnet holding plate 22. Like the shield plates 23-26, the magnet holding plate 22 is made of a magnetic metal and blocks the magnetic force of the permanent magnet 18 from penetrating into the housing 20. Therefore, the housing 20 can block the magnetic force of the permanent magnet 18, and the tilt detection sensor 28 and detection information transmission unit 29 inside are not affected by the magnetic force of the permanent magnet 18.

As shown in FIG. 5(a), the magnet holding plate 22 has an upper end and a lower end that are bent forward, and includes an upper housing mounting portion 22a and a lower housing mounting portion 22b. The housing portion 20 is attached to the upper housing mounting portion 22a and the lower housing mounting portion 22b via vibration-proof material 27.

As shown in Figures 5(a) and 5(b), the top shield plate 25 and bottom shield plate 26 of the housing 20 are attached to the upper housing mounting portion 22a and lower housing mounting portion 22b of the magnet holding plate 22 while being sandwiched between vibration-isolating material 27. The housing 20 is attached to the magnet holding plate 22 while being sandwiched between the vibration-isolating material 27, and is connected to the abutment portion 19.

In this embodiment, the vibration-proof material 27 is a gel bushing that uses silicone gel as the vibration-proof gel. The structure of the vibration-proof material 27 and the surroundings of the vibration-proof material 27 in the housing unit 20 will be described with reference to FIG. 6. FIG. 6 shows an enlarged view of the vibration-proof material 27 and its surroundings in the housing unit 20.

The vibration-proofing material 27 has a through hole 37 in the center through which the screw 35 passes. The through hole 37 has a cylindrical collar 38 that fits into its inner circumference. The top shield plate 25 and the bottom shield plate 26 are fixed to the upper housing mounting part 22a and the lower housing mounting part 22b while being sandwiched between the vibration-proofing material 27. The screw 35 holds the collar 38 in place via the washer 36. The screw 35 screws into the nut 33.

Because the collar 38 is made of a hard material such as metal, the tightening force of the screw 35 is received by the collar 38, and the tightening force of the screw 35 transmitted to the vibration-proof material 27, the top shield plate 25, and the bottom shield plate 26 is reduced by the collar 38. Therefore, the vibration-proof material 27 does not harden even when tightened by the screw 35 and nut 33, but remains in a gel state to clamp the top shield plate 25 and the bottom shield plate 26.

The housing 20 is connected to the magnet holding plate 22 at the top shield plate 25 and bottom shield plate 26 with vibration-isolating material 27 interposed between them. Therefore, traffic vibrations transmitted from the bridge 13 to the magnet holding plate 22 are absorbed by the vibration-isolating material 27, and transmission to the housing 20 is suppressed. Traffic vibrations are vibrations that occur on the ground and in structures such as buildings when vehicles are traveling.

The magnet holding plate 22 has permanent magnets 18 on both the left and right sides, and the magnet holding plate 22 is attached to the steel part of the bridge 13 by the attraction force of the permanent magnets 18. The back surface of the permanent magnets 18 and the yoke part 18a is the abutment part 19, which abuts against the steel part of the bridge 13.

The bridge monitoring device 10 can be attached to the bridge 13 by the attraction force of the permanent magnet 18, so the installation work can be easily performed and there is no need to prepare any additional parts on the bridge 13 side.

As shown in FIG. 5, the container 30 is fixed to a frame plate 42. The frame plate 42 has upper and lower plates extending forward, and stores the container 30 between the upper and lower plates. The frame plate 42 is attached to the side shield plate portion 23, thereby fixing the container 30 to the housing portion 20. The frame plate 42 is made of a magnetic metal and has a magnetic shielding function. The frame plate 42 prevents the magnetic force of the permanent magnet 18 from passing through, reducing the magnetic force of the permanent magnet 18 that reaches the container 30.

The container 30 has a rectangular box shape. The container 30 is composed of a container body 30a and a lid 30b. The container body 30a has an opening, and the lid 30b is configured to cover and close the opening of the container body 30a.

The outer wall of the container 30 is made of plastic resin and is designed to prevent rainwater, dust, etc. from entering the interior. The container 30 houses a tilt detection sensor unit 28, a detection information transmission unit 29, a control unit 40, a power supply unit 31, and a memory unit 32, which will be described later.

The container 30 is configured so that the opening of the container body 30a is covered with the lid 30b, preventing the intrusion of rainwater, dust, etc., and the tilt detection sensor unit 28, detection information transmission unit 29, control unit 40, power supply unit 31, and memory unit 32 housed inside are less susceptible to the effects of rainwater, dust, etc.

The antenna unit 21 is fixed to the bottom shield plate 26, with its tip extending downward. The antenna unit 21 is connected to the detection information transmission unit 29, and is used as an aerial for wireless communication by the LPWA. Since wireless communication signals are blocked by the magnetic shielding function of the housing unit 20, the antenna unit 21 is installed on the outside of the housing unit 20.

Next, the functions of the bridge monitoring device 10 will be described with reference to FIG. 7. FIG. 7 shows an example of a functional block diagram of the bridge monitoring device 10. As shown in FIG. 7, the bridge monitoring device 10 of this embodiment includes an inclination detection sensor unit 28, a detection information transmission unit 29, a control unit 40, a power supply unit 31, and a memory unit 32.

The tilt detection sensor unit 28 is equipped with a two-axis inclinometer. The two-axis inclinometer detects the x and y components of the gravitational acceleration, and detects the tilt angles of the bridge monitoring device 10 in the x-axis and y-axis directions based on the detected x and y components of the gravitational acceleration.

In this embodiment, the roll axis of the bridge monitoring device 10 is aligned with the x-axis of the dual-axis inclinometer, and the pitch axis of the bridge monitoring device 10 is aligned with the y-axis of the dual-axis inclinometer (see Figure 3). Therefore, the roll tilt amount of the bridge monitoring device 10 is calculated based on the y-component of the gravitational acceleration, and the pitch tilt amount of the bridge monitoring device 10 is calculated based on the x-component of the gravitational acceleration.

The dual-axis inclinometer may be mounted on the bridge monitoring device 10 with the pitch axis of the bridge monitoring device 10 aligned with the x-axis of the dual-axis inclinometer and the roll axis of the bridge monitoring device 10 aligned with the y-axis of the dual-axis inclinometer. In this case, the roll tilt amount of the bridge monitoring device 10 is calculated based on the x-component of the gravitational acceleration, and the pitch tilt amount of the bridge monitoring device 10 is calculated based on the y-component of the gravitational acceleration.

The detection information transmission unit 29 transmits the inclination of the bridge 13 detected by the inclination detection sensor unit 28 as detection information to the bridge monitoring system 12 via wireless communication using LPWA. LPWA is a communication standard that enables long-distance communication with low power consumption.

The detection information here may refer to the amount of tilt of the bridge monitoring device 10 calculated based on the x and y components of the gravitational acceleration detected by the tilt detection sensor unit 28, or may be the x and y components of the gravitational acceleration detected by the tilt detection sensor unit 28. However, when the x and y components of the gravitational acceleration detected by the tilt detection sensor unit 28 are transmitted to the bridge monitoring system 12 as detection information, the bridge monitoring system 12 calculates the amount of tilt of the bridge monitoring device 10 based on the x and y components of the gravitational acceleration.

LPWA is considered suitable for wireless communication by IoT (Internet of Things) devices, and is capable of wide-area wireless communication while consuming low power. In this embodiment, the SIGFOX (registered trademark) communication standard of LPWA is used. SIGFOX (registered trademark) has a maximum transmission distance of approximately 50 km, which is longer than the transmission distance of other LPWA communication standards, which are approximately 1 km to 10 km.

Other LPWA communication standards include LoRaWAN (registered trademark) and ELTRES (registered trademark), and these communication standards may be used depending on the usage conditions of the bridge monitoring system.

In addition to LPWA, there are other wireless communication methods such as third-generation (3G) and fourth-generation (4G) mobile communication systems, LTE (Long Term Evolution), and LTE-M (Long Term Evolution for machine-type-communication), and these wireless communication methods may be used depending on the usage conditions of the bridge monitoring system.

In this embodiment, signals and information are transmitted and received between the tilt detection sensor unit 28 and the detection information transmission unit 29 via a wired connection. The tilt detection sensor unit 28 and the detection information transmission unit 29 may be wirelessly connected via Bluetooth (registered trademark). Bluetooth (registered trademark) performs short-distance wireless communication over a distance of several meters to several tens of meters with portable information devices, etc.

The control unit 40 controls the operation of the tilt detection sensor unit 28, as well as the detection information transmission unit 29, and controls the operation of transmitting the detection information detected by the tilt detection sensor unit 28 to the bridge monitoring system 12.

The power supply unit 31 uses three primary lithium batteries 31a and supplies power to each functional unit of the bridge monitoring device 10. The number of primary lithium batteries 31a provided in the power supply unit 31 can be changed as appropriate depending on the usage conditions, such as the continuous usage period of the bridge monitoring device 10, and may be one, two, or four or more.

The memory unit 32 temporarily stores the detection information detected by the inclination detection sensor unit 28 until it is transmitted by the detection information transmission unit 29, and stores the programs necessary for controlling the operation of each functional unit of the bridge monitoring device 10, as well as initial setting information, etc.

With reference to Figures 8 and 9, the manner in which the tilt detection sensor unit 28, the detection information transmission unit 29, the control unit 40, the power supply unit 31, and the memory unit 32 are housed inside the container 30 will be described. Figure 8 shows the inside of the container 30, with (a) being a side view and (b) being a bottom view. Figure 9 shows an enlarged view of the vibration-proof material 27 and its surroundings in the container 30.

The tilt detection sensor unit 28 is implemented by forming a circuit including a two-axis inclinometer on the substrate 34. The detection information transmission unit 29, the control unit 40, and the memory unit 32 are implemented by forming a circuit (not shown) on the substrate 34. As shown in FIG. 8, the substrate 34 has a connector 34a to which the lead wire 31b of the primary lithium battery 31a of the power supply unit 31 is connected.

The substrate 34 is stored in the container 30 near the opening of the container body 30a, parallel to the bottom shield plate 26. Bosses 39 that receive screws are formed near the opening of the container body 30a, at each of the four corners of the inner wall of the container body 30a (see Figure 9).

The substrate 34 is placed on the top surface of the boss 39 and fixed with a screw 35 so that it is parallel to the bottom shield plate portion 26. A washer 36 is used in conjunction with the screw 35. The substrate 34 is sandwiched between gel bushings, which are vibration-isolating materials 27, and fixed inside the container 30. Since the substrate 34 is fixed to the boss 39 via the vibration-isolating materials 27, the vibration-isolating materials 27 can suppress the transmission of traffic vibrations of the bridge 13 to the substrate 34.

The vibration-proofing material 27 has a through hole 37 in the center through which the screw 35 passes. The through hole 37 has a cylindrical collar 38 that fits into its inner circumference. The substrate 34 is fixed to the boss 39 while being sandwiched between the vibration-proofing material 27. The screw 35 holds the collar 38 in place via the washer 36. The screw 35 screws into the nut 33.

Because the collar 38 is made of a hard material such as metal, the tightening force of the screw 35 is received by the collar 38, and the tightening force of the screw 35 transmitted to the vibration-proof material 27 and the substrate 34 is reduced by the collar 38. Therefore, even when the vibration-proof material 27 is fixed to the boss 39, it does not harden, and holds the substrate 34 in a gel state.

The two-axis inclinometer is manufactured using MEMS (Micro Electro Mechanical Systems) technology together with a sensor circuit (not shown). The two-axis inclinometer is housed integrally in a molded housing and detects linear acceleration in two axial (XY) directions parallel to the housing.

In the initial state, the dual-axis inclinometer has its housing horizontal, and measures the x and y components of the gravitational acceleration in a tilted state. The x and y components of the gravitational acceleration measured by the dual-axis inclinometer are transmitted to the bridge monitoring system 12 by the detection information transmission unit 29 as detection information of the tilt detection sensor unit 28.

The detection information of the tilt detection sensor unit 28 may include both the x and y components of the gravitational acceleration, and the tilt angle of the bridge monitoring device 10 calculated based on the x and y components of the gravitational acceleration. In this embodiment, the roll axis of the bridge monitoring device 10 is aligned with the x axis of the dual-axis inclinometer, and the pitch axis of the bridge monitoring device 10 is aligned with the y axis of the dual-axis inclinometer. Therefore, the pitch tilt amount of the bridge monitoring device 10 is calculated based on the x component of the gravitational acceleration, and the roll tilt amount is calculated based on the y component of the gravitational acceleration.

The two-axis inclinometer used in this embodiment was created using MEMS technology. By using a two-axis inclinometer that uses MEMS technology, the two-axis inclinometer becomes lightweight and small, which contributes to making the bridge monitoring device 10 lighter and smaller. Furthermore, by using MEMS technology, it becomes easier to integrate the element that detects the inclination and the signal processing circuit that processes the signal from this element, making it possible to reduce manufacturing costs.

In addition, in this embodiment, a capacitance type two-axis inclinometer is used. A capacitance type two-axis inclinometer consumes less power than a piezo-resistance type two-axis inclinometer, which contributes to power saving in the bridge monitoring device 10.

Next, the bridge monitoring system 12 according to this embodiment will be described with reference to Figures 10 and 11. The bridge monitoring system 12 is a type of information processing device such as a computer, which is mainly operated by a user, and includes an I/O interface 70, a Read Only Memory (ROM) 71, a Random Access Memory (RAM) 72, a storage unit 73, a Central Processing Unit (CPU) 74, etc.

The bridge monitoring system 12 transmits and receives data to and from external networks, including the Internet 14a, via the I/O interface 70. Alternatively, the bridge monitoring system 12 transmits and receives data to and from the LPWA platform 14 via the I/O interface 70.

The bridge monitoring system 12 stores a bridge monitoring program (described later) in the ROM 71 or the memory unit 73, and imports the bridge monitoring program into a main memory such as the RAM 72. The CPU 74 then accesses the main memory into which the bridge monitoring program has been imported and executes the bridge monitoring program.

The memory unit 73 of the bridge monitoring system 12 stores applications used to execute the bridge monitoring program, various data, other related applications, and related data.

Next, the functional configuration of the bridge monitoring system 12 will be described with reference to Fig. 11. The bridge monitoring system 12 includes a monitoring target setting unit 81, an inclination information acquisition unit 82, an inclination information determination unit 84, and a notification unit 86 in the CPU 74 by executing a bridge monitoring program.
The monitoring target setting unit 81 receives settings of the bridges 13 to be monitored by the bridge monitoring system 12 .

There may be one or more bridges 13 to be monitored. The bridge monitoring device 10 stores an identification code for identifying itself in the memory unit 32 of the bridge monitoring device 10. This identification code is an n-digit code, and the first m digits of the n digits are the bridge identification code that indicates the corresponding bridge 13.

The monitoring target setting unit 81 accepts the setting of the bridge 13 to be monitored by storing in the memory unit 73 an identification code linked to the bridge monitoring device 10 used by the bridge monitoring system 12. The bridge monitoring system 12 may use multiple bridge monitoring devices 10, and stores in the memory unit 73 an identification code linked to each of the multiple bridge monitoring devices 10.
The inclination information acquisition unit 82 acquires the detection information detected by the bridge monitoring device 10 via wireless communication.

The bridge monitoring device 10 pairs the detected detection information with its own identification code, links the detection information to the identification code, and transmits the paired detection information to the bridge monitoring system 12. The inclination information acquisition unit 82 acquires the detection information and the identification code as a pair. By referencing the identification code, it is possible to determine which bridge 13 and which bridge monitoring device 10 detected the acquired detection information. In this embodiment, LPWA is used for wireless communication.

The inclination information determination unit 84 determines whether the change in the inclination angle of the bridge 13 exceeds a predetermined threshold value based on the detection information acquired by the inclination information acquisition unit 82.

The bridge 13 is subject to traffic vibrations, wind and rain, and weak earthquakes, and sometimes undergoes small vibrations and slight inclinations. Therefore, a threshold is set by the user of the bridge monitoring system 12, and the system performs this determination to focus on the amount of change in the inclination angle of the bridge 13 that exceeds the threshold.

The notification unit 86 notifies the user of an abnormality in the bridge 13 when the inclination information determination unit 84 determines that the change in the inclination angle of the bridge 13 exceeds a predetermined threshold.

When a user is notified of an abnormality, they can refer to the identification code linked to the detection information that was the basis for the inclination angle of the bridge 13 to recognize which bridge 13 and in which bridge monitoring device 10 the abnormality in the inclination angle occurred.
When an abnormality in the inclination angle is reported, the user may conclude that it is dangerous for ordinary vehicles to travel across the bridge 13.

Next, referring to FIG. 12, a bridge monitoring method according to the present disclosure will be described together with the bridge monitoring program using a flowchart showing the flow of the bridge monitoring program. The bridge monitoring method according to the present disclosure is executed by the CPU 74 of the bridge monitoring system 12 based on the bridge monitoring program.

The bridge monitoring program causes the CPU 74 in FIG. 10 to execute each of the following functions: monitoring target setting function, inclination information acquisition function, inclination information determination function, and notification function. These functions are executed in the order shown in the figure, but the order can be changed as appropriate. Note that each function overlaps with the description of the bridge monitoring system 12 described above, so detailed description thereof will be omitted.

The monitoring target setting function accepts the setting of the bridge 13 to be monitored by the bridge monitoring system 12 (81S: monitoring target setting step).
The inclination information acquisition function acquires detection information detected by the bridge monitoring device 10 via wireless communication (82S: inclination information acquisition step).

The inclination information determination function determines whether the change in the inclination angle of the bridge 13 has exceeded a predetermined threshold based on the detection information acquired by the inclination information acquisition function (84S: inclination information determination step).

The notification function notifies the user of an abnormality in the bridge 13 when the inclination information determination function determines that the change in the inclination angle of the bridge 13 exceeds a predetermined threshold (86S: notification step).

The above-described embodiment makes it possible to achieve the following. That is, the bridge monitoring device 10 detects the inclination of the bridge 13 using a capacitance-type two-axis inclinometer. A capacitance-type two-axis inclinometer consumes less power than other types of two-axis inclinometers. Therefore, the bridge monitoring device 10 has excellent power-saving performance.

Furthermore, the bridge monitoring device 10 uses LPWA as a wireless communication method when transmitting detection information to the bridge monitoring system 12. LPWA consumes less power than other communication methods. Therefore, the bridge monitoring device 10 has excellent power saving performance.

Furthermore, the housing unit 20 is constructed using a magnetic metal and has a magnetic shielding function, so the tilt detection sensor unit 28 housed inside can detect tilt without being affected by the magnetic field of the permanent magnet 18.

Furthermore, the housing part 20 is fixed to the abutment part 19 while being sandwiched between the vibration-proof material 27, so that traffic vibrations on the bridge 13 are reduced by the vibration-proof material 27 interposed between the housing part 20 and the abutment part 19, and the effects of traffic vibrations on the tilt detection sensor part 28 housed inside the housing part 20 can be suppressed.

Furthermore, the substrate 34 is fixed inside the container 30 while being sandwiched between the vibration-proofing material 27. Therefore, even if traffic vibrations from the bridge 13 are transmitted to the container 30, they are reduced by the vibration-proofing material 27, and the effects of traffic vibrations on the substrate 34 stored inside the container 30 can be suppressed.

Furthermore, the container body 30a and the lid 30b of the container 30 are made of plastic resin, and the opening of the container body 30a is configured to be closed by the lid 30b. This configuration of the container 30 makes it possible to prevent rainwater, dust, etc. from entering the inside of the container 30.

Furthermore, in the above embodiment, the bridge monitoring device 10 is installed on the steel part of the bridge 13 by the attractive force of the permanent magnet 18. Therefore, the bridge monitoring device 10 can be easily installed on the bridge 13, and there is no need to prepare any additional parts on the bridge 13 side.

The present disclosure is not limited to the bridge monitoring system according to the embodiment described above, but may be implemented in various other modified or applied examples without departing from the gist of the present disclosure as set forth in the claims.

In the above embodiment, the bridge monitoring device 10 uses LPWA as wireless communication when transmitting detection information to the bridge monitoring system 12. However, instead of LPWA, wireless communication using a wireless communication method such as a third generation (3G) or fourth generation (4G) mobile communication system or LTE may be used.

10 Bridge monitoring device 12 Bridge monitoring system 13 Bridge 14 LPWA platform 14a Internet 15 Bridge body 16 Pier 17 Bearing 18 Permanent magnet 18a Yoke section 19 Contact section 20 Housing section 21 Antenna section 22 Magnet holding plate 22a Upper housing mounting section 22b Lower housing mounting section 23 Side shield plate section 24 Front shield plate section 25 Top shield plate section 26 Bottom shield plate section 27 Vibration-proof material 28 Tilt detection sensor section 29 Detection information transmission section 30 Container 30a Container body 30b Lid 31 Power supply section 31a Primary lithium battery 31b Lead wire 32 Memory section 33 Nut 34 Board 34a Connector 35 Screw 36 Washer 37 Through hole 38 Collar 39 Boss 40 Control section 42 Frame plate

Claims (7)

A bridge monitoring system for monitoring a bridge using a bridge monitoring device,
The bridge monitoring device includes:
a contact portion that contacts the bridge;
a housing portion connected to the contact portion via a vibration isolating material;
An inclination detection sensor unit that is accommodated inside the housing and detects an inclination of the bridge that is in contact with the contact portion;
a detection information transmission unit that transmits the detection information detected by the inclination detection sensor unit by wireless communication, by pairing the detection information with an identification code unique to the bridge monitoring device;
the tilt detection sensor unit is fixed to the housing unit via another vibration-isolating material different from the vibration-isolating material,
The first girder of the identification code is the bridge identification code of the corresponding bridge,
a monitoring target setting unit that receives settings of bridges that are monitoring targets of the bridge monitoring system;
an inclination information acquisition unit that acquires the detection information detected by the bridge monitoring device via the wireless communication;
an inclination information determination unit that determines whether or not a change in an inclination angle of the bridge has exceeded a predetermined threshold based on the detection information acquired by the inclination information acquisition unit;
a notification unit that notifies a user of an abnormality in the bridge when the inclination information determination unit determines that a change in the inclination angle of the bridge exceeds a predetermined threshold;
A bridge monitoring system comprising: 2. The bridge monitoring system according to claim 1 , wherein the vibration-proofing material comprises a gel-like material, and vibrations are reduced by the gel-like material. The bridge includes a portion made of steel,
The bridge monitoring system according to claim 1 , wherein the contact portion includes a magnet on a surface portion that contacts the portion made of steel. 4. The bridge monitoring system according to claim 3 , wherein the housing portion is magnetically shielded so as to block the magnetic force of the magnet provided in the contact portion. 2. The bridge monitoring system according to claim 1 , wherein the inclination detection sensor unit detects the inclination of the bridge using a two-axis inclinometer. A bridge monitoring method for monitoring a bridge using a bridge monitoring device, comprising:
The bridge monitoring device includes:
a contact portion that contacts the bridge;
a housing portion connected to the contact portion via a vibration isolating material;
An inclination detection sensor unit that is accommodated inside the housing and detects an inclination of the bridge that is in contact with the contact portion;
a detection information transmission unit that transmits the detection information detected by the inclination detection sensor unit by wireless communication by pairing the detection information with an identification code unique to the bridge monitoring device;
the tilt detection sensor unit is fixed to the housing unit via another vibration-isolating material different from the vibration-isolating material,
The first girder of the identification code is the bridge identification code of the corresponding bridge,
a monitoring target setting step of accepting a setting of a bridge that is a monitoring target of the bridge monitoring method;
an inclination information acquisition step of acquiring the detection information detected by the bridge monitoring device via the wireless communication;
an inclination information determination step of determining whether or not a change in the inclination angle of the bridge has exceeded a predetermined threshold based on the detection information acquired by the inclination information acquisition step;
a notification step of notifying a user of an abnormality in the bridge when the inclination information determination step determines that the amount of change in the inclination angle of the bridge has exceeded a predetermined threshold;
A bridge monitoring method comprising: A bridge monitoring program for monitoring a bridge using a bridge monitoring device,
The bridge monitoring device includes:
a contact portion that contacts the bridge;
a housing portion connected to the contact portion via a vibration isolating material;
An inclination detection sensor unit that is accommodated inside the housing and detects an inclination of the bridge that is in contact with the contact portion;
a detection information transmission unit that transmits the detection information detected by the inclination detection sensor unit by wireless communication, by pairing the detection information with an identification code unique to the bridge monitoring device;
the tilt detection sensor unit is fixed to the housing unit via another vibration-isolating material different from the vibration-isolating material,
The first girder of the identification code is the bridge identification code of the corresponding bridge,
Computers used in bridge monitoring systems include:
A monitoring target setting function that accepts settings for bridges to be monitored;
An inclination information acquisition function that acquires the detection information detected by the bridge monitoring device via the wireless communication;
an inclination information determination function that determines whether or not a change in the inclination angle of the bridge exceeds a predetermined threshold based on the detection information acquired by the inclination information acquisition function;
a notification function that notifies a user of an abnormality in the bridge when the inclination information determination function determines that a change in the inclination angle of the bridge exceeds a predetermined threshold;
A bridge monitoring program that realizes the above.

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