KR100991867B1 - Method for measuring bridge scour using optical fiber sensor - Google Patents

Abstract

By measuring the temperature, water temperature, and underwater surface temperature according to the temperature measurement principle of the optical fiber sensor, and grasping the bridge scour in response to each temperature change, it can be applied to the continuous measurement system of the bridge. A bridge scour measuring method using an optical fiber sensor that can measure bridge scour in real time by greatly shortening is provided. In the method of measuring bridge scour using optical fiber sensor, a method of measuring bridge scour by installing an optical fiber sensor capable of measuring temperature from the bottom of the bridge deck to the underwater surface includes: a) reference data about the temperature and criteria related to scour amount Setting location data; b) detecting a change in temperature of the surface of the water and the surface of the water using an optical fiber sensor; c) determining the change position of the atmospheric temperature and the water temperature based on the reference data on the temperature, and identifying the change position of the water temperature and the surface of the water surface; d) calculating the heights of the water surface and the underwater surface from the reference position below the bridge deck; And e) calculating a bridge scour amount by comparing the calculated heights of the surface of the water and the surface of the water with reference position data related to the predetermined scour amount.

Bridge scour measurement, fiber optic sensor, phase clock side, temperature measurement, scour amount

Description

Method of measuring bridge scour using optical fiber sensor {Method for measuring bridge scour using optical fiber sensor}

The present invention relates to a method for measuring bridge scour, and more particularly, to a method for measuring bridge scour using an optical fiber sensor for continuous measurement of bridge scour.

Bridge scour refers to a phenomenon in which the flow of fluid loses riverbed material around bridge bridges and bridges, and the difference between the lowered riverbed and the natural riverbed is called scouring. For example, the flow velocity and thus the shear stress caused by the riverbed increase rapidly when a flood occurs in the river basin, causing more soil to erode and move along the river boundary. In particular, hydraulic structures, such as piers or shifts, located within a stream, generate scour around the structure by accelerating the flow or forming vortices, causing a change in flow type.

The pattern of scouring may vary depending on the flow characteristics as well as the composition of the bed material. Loose particles of soil are scoured rapidly by running water, but cohesive or compacted soils are more resistant to scour. However, cohesive or compacted soils may have a final scour depth similar to that of sandy soils if flood events last long enough. At this time, determining the amount of scour is very complicated because of the periodic nature of the scour process. The scour depth can be maximum near the maximum flow rate during flooding, but as the flow rate and flow rate decrease, the scour hole refills with sediment and becomes smaller than the maximum scour depth.

On the other hand, the type of scour that can occur in the bridge cross section can be classified into long term streambed elevation change, section scour and local scour. Here, long-term river fluctuations are fluctuations in riverbed heights occurring in a long or short term regardless of the existence of bridges. Sectional scouring is a scour caused by the reduction of the cross-sectional area of the river due to natural structures or natural factors such as bridges. In addition, local scour refers to scour caused by the development of vortex caused by disturbed flow by the structure and accelerated flow. Typically, the total scour around the piers, or alternations, is calculated by adding all three scour components, long-term bed fluctuations, cross-sectional scour, and local scour.

On the other hand, to reduce the damage of the bridge due to the aforementioned scour, continuous maintenance of the bridge infrastructure is required, and through this, the progress of scour and the integrity of the bridge must be accurately investigated and evaluated.

The method of investigating scour conditions around the foundation of the bridge includes basic methods such as a worker entering the lower part of the bridge or the water while wearing a waterproof suit, measuring the depth with a sounding pole, and investigating the scour depth in a boat. There is a way. In the former case, the measurable space range is limited, time consuming and operator safety depending on the depth and flow rate. In the latter case, the spatial measurement range and accuracy are higher than the former, but the overall work time including preparation is long. In addition, the underwater survey method using a diver is currently used for the basic condition investigation and scour depth measurement of the underwater bridge where the foundation is always submerged in the bridge on the national road managed by the Ministry of Construction and Transportation. This method has the disadvantage of being difficult to investigate at high flow rates, slow progress, and expensive.

Specifically, the bridge scrubbing method according to the related art includes a portable scour measuring device, a scour measuring device using a floating rod, a scour irradiation device using a fixed rod, a scouring device using a robot arm, and a remotely controlled boat system.

First, a portable scour measuring device is used to investigate the scour state under the bridge in a relatively small bridge. The instrument measures the scour depth near the piers using a sounding device mounted near the bottom of the bar while the worker is holding the hand near the water pole. By the way, the portable scour measuring device has a weight of up to 75kg including a rod (rod), the scour measurement data can be collected in real time in the field. However, it is difficult to measure scour in deep water, large bridges, and high speeds, and it is impossible to measure several points around the bridge because only vertical measurements can be performed at the top of the bridge.

Next, the scour measuring device using the float is equipped with a fish-finder type sonar instrument on the float platform that can float on the surface, and can measure the scour depth around the bridge at a low cost. have. In addition, the floating zone moves freely around the bridge, allowing extensive scrutiny of scour exploration sites. However, this method is not applicable to large rivers, high speed flows, or places affected by wind.

Next, in the scour irradiation device 10 using a fixed pole, as shown in FIG. 1, after the operator 12 sends the fixed rod 13 down to the pier / shift 11, The ultrasonic scour sensor 14 measures the scour state around the piers / shifts 11 and is mainly used to analyze the scour depth over time through long term measurement of scour conditions for a single point. 1 is a view for explaining a scour irradiation method using a fixed bar according to the prior art, Figures 2a to 2c is a case of the fixed bar of Figure 1 is a ring type, electromagnetic type and color image sound wave type respectively Are drawings.

In the scour measurement technique used for long-term measurement, as shown in FIG. 2A, the ring moves according to the change of the bottom surface to determine the change as the scour depth, as shown in FIG. 2B. Electromagnetic type method that can measure flow velocity and depth by mounting electromagnetic wave sensor, and color-imaged sonar type that shows the cross section of measurement point as an image as shown in Fig. 2c. ) And the like.

 The scour irradiation method using the fixed bar 13 has a merit that the measurement result is relatively accurate, various sensors can be used, and long-term measurement is possible, but the analysis time is relatively long and the installation location is limited. In addition, the periodic management of the scrubbing device is very important, and it is necessary to consider this in the site where the water level changes significantly.

Next, the scour irradiation apparatus using the robot arm may be adjusted to the scour depth at a desired position by adjusting the robot arm in the vehicle above the bridge. The device can be measured at a height of about 5 to 15 meters from the top of the bridge to the surface of the water, which is safe, time efficient, and can be analyzed in the field. However, the equipment is expensive, and in places with a lot of traffic, such as Korea, there is a disadvantage that can cause obstacles in the surrounding traffic due to the equipment vehicle during the measurement.

Next, the remote controlled boat system 30 can automatically measure the depth of scour depth and can extensively analyze the scour conditions around the bridge. The remote control boat system 30 includes a scour measurement sensor 32, a remote control boat 31 of about 1 m length, a measurement data transmission device 34 and a location information device 33 of a remote control boat, and data storage and analysis. It consists of a device (PC and analysis program: 36). 3 is a view illustrating the measurement of the scour state of the river by a remote control system according to the prior art, Figure 4 is a analysis of the scour state of the irradiation area according to the prior art in a two-dimensional and three-dimensional image It is an illustration to illustrate.

As shown in FIG. 3, after installing a sonic echometer (Fathometer) 32, which is a scour measuring ultrasonic sensor, below the remote control boat 31, a worker remotely controls the stream by a transmitter 34 in a nearby land. The scour state is measured, and the scrubbing state of the irradiated area can be analyzed by 2D and 3D images as shown in FIG. 4. That is, the worker's transmission device 34 communicates with the location information device 33 in the remote control boat 31 to collect and measure data, and then stores and analyzes the location information of the remote control boat 31. Transmitted to device 36 to analyze and display the scour state. At this time, the data storage and analysis device 36 may receive the scour depth data through the receiver 35.

5 is a view for comparing the characteristics and disadvantages of the scour irradiation apparatus according to the prior art, the above-described portable scour measuring device, scour measuring device using a float, scour irradiation device using a fixed rod, scour using a robot arm Features and disadvantages of the irradiator and remote control boat system are shown, respectively.

On the other hand, as a related technology, Korean Patent Application No. 2006-90335 (Application Date: September 18, 2006) discloses the invention named "bridge scour measuring device". Bridge scour measuring device according to the related art, the end is located on the bottom surface of the river with the bridge is guided to the main body is installed on the upper side of the river and the descending by the weight according to the scour on the bottom of the river and installed in the main body And measuring means connected to the transducer to measure the depth of descent of the transducer, and elevating means installed on the main body to elevate the transducer, so that an operator can not directly descend to the lower portion of the bridge or obtain water underwater. The scour depth can be measured simply and accurately. However, such a bridge scour measuring device is similar to the scour irradiation device using the fixed rod described above, there is a problem that the analysis takes a relatively long time, and can only measure the local scour depth.

However, the pier and alternating scour measurement / irradiation apparatuses according to the prior art have disadvantages as shown in FIG. 4, and in particular, are difficult to apply to the bridge measurement system.

The technical problem to be solved by the present invention to solve the above problems is to measure the temperature, water temperature and underwater surface temperature according to the temperature measurement principle of the optical fiber sensor, and to identify the bridge scour in response to each temperature change, An object of the present invention is to provide a method for measuring bridge scour using an optical fiber sensor applicable to a measurement system.

Another technical problem to be achieved by the present invention is to provide a bridge scour measuring method using an optical fiber sensor that can measure bridge scour in real time by greatly reducing the analysis time with a simple configuration.

As a means for achieving the above technical problem, the method of measuring bridge scour using the optical fiber sensor according to the present invention is a method of measuring the bridge scour by installing an optical fiber sensor capable of measuring temperature from the bottom of the bridge deck to the underwater surface A method comprising: a) setting reference data for temperature and reference position data related to scour amount; b) detecting temperature changes of water surface and underwater surface using the optical fiber sensor; c) determining a change position of the atmospheric temperature and the water temperature based on the reference data for the temperature, and identifying a change position of the water temperature and the underwater surface; d) calculating the heights of the water surface and the underwater surface from the reference position below the bridge deck; And e) calculating a bridge scour amount by comparing the calculated heights of the water surface and the underwater surface with the predetermined reference position data related to the amount of scour.

Here, the bridge scrubbing amount of step e) is characterized in that the boundary between the water surface and the water surface is divided into the distance from the reference position below the bridge bottom plate by distinguishing the difference between the geothermal temperature, water temperature and air temperature.

Here, the bridge scour amount of step e) is a difference value between the height data of the water surface and the underwater surface surface calculated according to the reference data from the lower part of the bridge bottom plate to the ground surface before the scour data and the temperature change after the scour data. It features.

Here, the data before and after scouring may vary according to changes in daily temperature of air temperature, water temperature, and geothermal temperature, or may vary according to seasonal temperature changes.

Here, the change position of the atmospheric temperature and the water temperature of step c) represents the water level from the bottom of the bridge deck, and the temperature change position of the water temperature and the underwater surface of the step c) represents the water depth from the water surface. do.

Here, the method of measuring bridge scour using the optical fiber sensor according to the present invention may further include f) displaying in two or three dimensions according to the calculated bridge scour amount.

According to the present invention, by measuring the air temperature, water temperature and underwater surface temperature according to the temperature measurement principle of the optical fiber sensor, and grasps the bridge scour in response to each temperature change, it can be applied to the bridge measurement system.

According to the present invention, bridge scour can be measured in real time by drastically shortening the analysis time with a relatively simple configuration.

According to the present invention, by measuring the bridge scour based on the optical fiber sensor, it can exhibit excellent compatibility with other optical fiber sensor-based bridge measurement systems.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

As an embodiment of the present invention, the bridge scour measurement method using an optical fiber sensor that can measure the air temperature, water temperature and the surface water surface temperature according to the temperature measurement principle of the optical fiber sensor, and can grasp the bridge scour in real time corresponding to each temperature change Is provided.

6 is a view illustrating a principle of measuring bridge scour using an optical fiber sensor according to an embodiment of the present invention, and FIG. 7 is a flowchart illustrating a method of measuring bridge scour using an optical fiber sensor according to an embodiment of the present invention.

Referring to FIG. 6, a bridge scour measuring system 100 using an optical fiber sensor according to an exemplary embodiment of the present invention may include a bridge upper plate 110, a bridge or a bridge 120a and 120b, a data logger or a wireless communication device 130. , Optical fiber sensors 140a and 140b, a scour amount calculating unit 150, and a display unit 160. Here, the optical fiber sensors 140a and 140b are installed from the bottom of the bridge bottom plate to the underwater ground surface to measure air temperature, water temperature, and geothermal temperature.

When the data logger or the wireless communication device 130 is a data logger, the amount of scour is directly calculated according to the temperature data measured by the optical fiber sensors 140a and 140b, and the data logger or the wireless communication device 130 is wireless. In the case of a communication device, the temperature data measured by the optical fiber sensors 140a and 140b is transmitted to the scour amount calculation unit 150, and the bridge scour amount calculated as described above is two-dimensional or three-dimensional through the display unit 160. Can be displayed in dimensions. In detail, the data logger 130 acquires data in real time or at regular intervals from the local or remote system in real time. Also, the wireless communication unit may be implemented in the form of a wireless communication module, and may be a Bluetooth module for short range communication of less than 1.2 km or a code division multiple access (CDMA) method for long distance communication. It may be a modem.

The pier scour measurement system 100 is a technology that applies the temperature measurement principle of the optical fiber sensor (140a, 140b) to improve the scour irradiation behavior device using the existing fixed rod, and significantly shorten the analysis time with a simple structure compared to the existing method The scour can be measured in real time. Bridge scour measuring method according to such a configuration will be described in detail below.

6 and 7, in the method of measuring bridge scour using an optical fiber sensor according to an exemplary embodiment of the present invention, first, optical fiber sensors 140a and 140b capable of measuring temperature are installed from a bottom of a bridge deck to an underwater surface. (S110). Specifically, the optical fiber sensors 140a and 140b are installed to a predetermined depth of the underwater surface in consideration of bridge scour.

Next, reference data about the temperature and reference position data related to the amount of scour are set (S120). In this case, the data before and after scrubbing may vary according to the change in daily temperature of the air temperature, water temperature, and geothermal temperature, or may vary according to the seasonal temperature change. The data may be stored in the logger or the wireless communication device 130 or the data storage unit (not shown) of the scour amount calculator 150.

Next, the temperature change of the water surface and the underwater surface is detected using the optical fiber sensors 140a and 140b (S130).

Next, the position of change of the atmospheric temperature and the water temperature is determined based on the reference data for the temperature (S140), and the position of the temperature change of the water temperature and the underwater surface is determined (S150). In this case, the change position of the atmospheric temperature and the water temperature is, for example, a point indicated by reference numeral A in FIG. 6, indicating a water level (L1 in FIG. 6) from the bottom of the bridge deck, and the water temperature and the underwater surface of the water. The temperature change position of is, for example, a point indicated by reference numeral B in FIG. 6, and represents the depth of water (L2 in FIG. 6) from the water surface.

Next, the height (D1 of FIG. 6) of the water surface and the underwater ground surface is calculated from the reference position under the bridge bottom plate (S160).

Next, a bridge scrubbing amount (D2 of FIG. 6) is calculated by comparing the calculated heights of the water surface and the underwater surface with the predetermined scouring quantity-related reference position data (S170). Here, the bridge scour amount is divided into the difference between the geothermal temperature, water temperature and air temperature is converted into the distance from the reference position of the bottom of the bridge bottom plate the boundary between the water surface and the underwater surface. In addition, the bridge scour amount, as shown by the reference numeral C in FIG. 6, the water surface and the water calculated according to the temperature change that is the reference data from the bottom of the bridge bottom plate, which is the pre-cleaning data to the ground surface, and the data after the scouring The difference between the height data of the earth's surface.

Next, it may be displayed in two or three dimensions according to the calculated bridge scour amount (S180).

On the other hand, Figure 8 is a view for explaining in detail the bridge scrubbing measurement concept using the optical fiber sensor according to an embodiment of the present invention, Figure 9 is a view illustrating the bridge scour measurement data using the optical fiber sensor according to an embodiment of the present invention Drawing.

First, when measuring bridge scour using the optical fiber sensor according to an embodiment of the present invention, the method of calculating the position of the surface of the water surface and the surface of the underwater surface is as follows.

The daily temperature change can be different in geothermal temperature, water temperature and temperature even on the same day. For example, in general, the temperature change is the largest, the next large change is the water temperature, and the change in the geothermal temperature is almost insignificant. In addition, the amount of change in temperature may vary depending on the season, for example, in general, in summer, the temperature is the highest, the water temperature is the next highest, and the lowest temperature. In winter, the temperature is the lowest, the water temperature is the next lowest, and the highest.

As such, by using or combining the daily or seasonal temperatures individually, the amount of scour and depth can be measured by measuring the position of the water surface and the position of the underwater surface in real time or daily.

For example, daily or seasonal differences in geothermal temperature, water temperature and temperature, as shown in Figure 8, pre-winter temperature 810, pre-summer temperature 820, post-winter winter temperature 830, after washing The boundary between the water surface and the underwater surface is divided into the distance from the reference position under the bridge deck by dividing it into a summer temperature 840, a change in the temperature before the scour 850 and a change in the temperature after the scour 860. 9 illustrates, but is not limited to, bridge scour measurement data using an optical fiber sensor.

In addition, when measuring the bridge scour using the optical fiber sensor according to an embodiment of the present invention, when using the optical fiber sensor, it is possible to measure the temperature change of all the gauges with one optical sensor. Or, it will be apparent to those skilled in the art that temperature gauges can be measured at regular intervals instead of using optical fiber sensors to measure the temperature according to the height of bridges and bridges.

For example, in the case of the current commercially available products, one optical fiber sensor can detect a change in temperature of several tens of kilometers at an interval of 1 m, and when the temperature optical fiber sensor is connected in series, Temperature changes can be detected at 30 cm intervals, but are not limited to this.

On the other hand, the optical fiber sensor can observe the behavior of the structure by detecting a change in the physical quantity to be measured using the amplitude, phase, or polarization of the light passing through the optical fiber. Among optical fiber sensors, a sensor using a fiber Bragg Grating (FBG) has recently been spotlighted as a new optical fiber sensor. The FBG sensor gives a periodic refractive index modulation to the optical fiber core to reflect light of a specific wavelength, and shows low insertion loss and high wavelength selectivity.

10A and 10B are diagrams illustrating the structure and principle of an optical fiber sensor according to an embodiment of the present invention, respectively.

FIG. 10A illustrates a principle of an optical fiber sensor. When a light source is incident on an optical fiber sensor 140 including a cladding 141 and a core 142, a specific wavelength component due to Bragg conditions is an optical fiber Bragg grating. Reflected at 143, the remaining wavelength components pass through as they are.

In detail, the propagation principle of light in the optical fiber is a total reflection principle in which all light within a predetermined angle is reflected at the interface when light travels from a high refractive index material to a low material. It is reflected at the interface between the high refractive index core layer and the low refractive index cladding 141 layer and propagates along the optical fiber core 142. The main component of the optical fiber is made of silica glass, and its structure is composed of a portion of the optical fiber core 142 with germanium and a portion of the cladding 141 which protects the center so that the refractive index is slightly higher. The Bragg grating 143 inscribes a grating having periodic refractive index changes to the optical fiber by using a phenomenon in which the refractive index increases by about 10 ⁻⁵ when the germanium-doped optical fiber core portion is exposed to light in the ultraviolet region.

At this time, the Bragg wavelength reflected by the Bragg grating 143 is a function of the effective refractive index and the grating spacing, and when Bragg grating 143 is subjected to an external physical quantity such as a short distance strain, the Bragg wavelength is changed by these values. By accurately measuring the change in Bragg wavelength, an unknown physical quantity applied to the optical fiber grating can be obtained.

Since the measurement amount of the optical fiber sensor 140 is a change amount of the Bragg reflection wavelength, the measurement is easy, and since the line width of the reflection wavelength of the Bragg grating 143 is narrow, a sensor having high resolution may be configured. In addition, since optical fibers having different Bragg reflection wavelengths are not affected by each other, multi-point measurement using one optical fiber is possible.

Referring to FIG. 10B, in the optical fiber sensor 140, a plurality of gratings are used for one strand of optical fiber. In this case, by varying the reflection wavelength of each grating 143, a specific grating 143 from the spectrum of the reflected light source is used. You can easily distinguish the physical quantity that) undergoes. This method is called a wavelength division method.

Bragg Wavelength ( λ _B ) Can be obtained by λ _B = 2nΛ , where n is the effective refractive index of the optical fiber core and Λ is the grating period between the grating 83 and the grating 143.

The Bragg wavelength reflected by the Bragg grating 143 is a function of the effective refractive index and the lattice spacing. When an external physical quantity is applied to the optical fiber sensor 140, the Bragg wavelength is changed. Therefore, if the Bragg wavelength is measured, the Bragg wavelength is applied to the FBG. The physical quantity can be found.

In the case of the optical fiber sensor 140, the measured strain information is represented as a change in wave length instead of a path difference. The rate of change of Bragg wavelength with respect to the applied physical quantity is linear, and thus, by accurately measuring the amount of change in the wavelength, information about the applied physical quantity can be calculated in reverse. In addition, since the strain is measured by the displacement of the wavelength, it is possible to measure the absolute amount of deformation irrespective of the fluctuation of the light intensity by the light source, the light splitter, and the optical coupler, which are common in the interferometric optical fiber system. In addition, the FBG sensor 140 can be easily expanded to a multi-point sensor using a fiber grating of which wavelengths are slightly changed, and it can be used to construct a pre-monitoring system for bridges and buildings.

The optical fiber sensor 140 is currently used as a monitoring system for civil structures, such as actual bridges and tunnels. That is, one of the biggest applications of the optical fiber sensor 140 is to diagnose the state of the structure. For example, when manufacturing a bridge, a dam, a building, etc., an FBG sensor may be installed in concrete, and the safety state of the structure may be diagnosed by detecting a tension distribution or bending degree inside the structure.

On the other hand, although the optical fiber sensor is used in the bridge scrubbing measuring method according to an embodiment of the present invention, it is also possible to measure the temperature according to the height of the bridge and the alternating through a temperature gauge installed at a predetermined interval.

As a result, an embodiment of the present invention is a method for estimating the position of the surface of the water surface and the surface of the water surface by analyzing the temperature obtained through the optical fiber sensor or temperature gauge installed from the bottom of the bridge deck to the predetermined basement through the bridge and alternating, Through this, it is possible to easily measure the amount of scour and the depth of the piers and bridges installed in the river in real time.

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

1 is a view for explaining a scour irradiation method using a fixed rod according to the prior art.

2A to 2C are diagrams illustrating a case where the fixing bar of FIG. 1 is a ring type, an electromagnetic type, and a color image sound wave type, respectively.

3 is a diagram illustrating measuring the scour state of a river by a remote control system according to the prior art.

4 is a diagram illustrating a two-dimensional and three-dimensional image analysis of the scour state of the irradiation area according to the prior art.

5 is a view for comparing the features and disadvantages of scour irradiation apparatus according to the prior art.

6 is a view illustrating a principle of measuring bridge scour using an optical fiber sensor according to an exemplary embodiment of the present invention.

7 is a flowchart illustrating a method of measuring bridge scour using an optical fiber sensor according to an exemplary embodiment of the present invention.

8 is a view for explaining in detail the concept of the bridge scour measurement using the optical fiber sensor according to an embodiment of the present invention.

9 is a diagram illustrating bridge scour measurement data using an optical fiber sensor according to an embodiment of the present invention.

10A and 10B are diagrams illustrating the structure and principle of an optical fiber sensor according to an embodiment of the present invention, respectively.

<Brief Description of Drawings>

100: bridge scour measurement system using optical fiber sensor

110: bridge deck 120a, 120b: pier / shift

130: data logger / wireless communication device 140, 140a, 140b: fiber optic sensor

150: scour amount calculation unit 160: display unit

Claims (8)

In the method of measuring bridge scour by installing an optical fiber sensor capable of measuring temperature from the bottom of the bridge deck to the underwater surface a) setting reference data for temperature and reference position data related to the amount of scour; b) detecting temperature changes of water surface and underwater surface using the optical fiber sensor; c) determining a change position of the atmospheric temperature and the water temperature based on the reference data for the temperature, and identifying a change position of the water temperature and the underwater surface; d) calculating the heights of the water surface and the underwater surface from the reference position below the bridge deck; And e) calculating a bridge scour amount by comparing the calculated heights of the water surface and the water surface with the reference position data related to the predetermined scour amount; Bridge scour measurement method using an optical fiber sensor comprising a. The method of claim 1, The bridge scrubbing amount of step e) is a bridge using an optical fiber sensor, characterized in that the boundary between the water surface and the water surface is converted into a distance from a reference position below the bridge bottom plate by dividing the difference between geothermal temperature, water temperature and air temperature. Scour measurement method. The method of claim 1, The bridge scour amount of step e) is a difference value between the height data of the water surface and the underwater surface surface calculated according to the reference data from the bottom of the bridge bottom plate, which is the data before the scour, to the ground surface, and the temperature change that is the data after the scour. Bridge scour measurement method using optical fiber sensor. The method of claim 3, The method before and after scrubbing data depends on the amount of change in daily temperature of air temperature, water temperature and geothermal bridge scrubbing method using the optical fiber sensor. The method of claim 3, The method before and after scouring data is based on the seasonal temperature change of temperature, water temperature and geothermal bridge scrubbing method using the optical fiber sensor. The method of claim 1, The method of measuring bridge scour using an optical fiber sensor, characterized in that the change position of the atmospheric temperature and the water temperature of step c) indicates the water level from the bottom of the bridge deck. The method of claim 1, The method of measuring bridge scrubbing using an optical fiber sensor, characterized in that the position of the water temperature and the temperature change position of the underwater surface of the step c) represents the depth from the water surface. The method of claim 1, f) Bridge scouring measurement method using an optical fiber sensor further comprising the step of displaying in two or three dimensions according to the calculated bridge scour amount.

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