JP2011164024A - Method and device of calculating amount of deflection of structure provided with optical fiber sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device of calculating an amount of deflection of a structure provided with an optical fiber sensor capable of calculating the amount of the deflection of the structure according to a construction progress. <P>SOLUTION: The method of calculating the amount of the deflection includes measuring upper-side strain and lower-side strain of the structure with the optical fiber sensor, dividing a difference between the upper-side strain and the lower-side strain measured with the optical fiber sensor by a vertical height of the structure to obtain deflection curvature regulating the amount of the deflection, integrating the deflection curvature twice concerning a horizontal direction of the structure to obtain a basic deflection amount consisting of a numerical equation including any arbitrary integral constant, applying a boundary condition in a prescribed construction progress of the structure for the basic deflection amount to determine a value of an integral constant, and calculating the amount of the deflection in the prescribed construction progress of the structure on the basis of the basic deflection amount substituted with the value of a determined integral constant. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method and an apparatus for calculating a deflection amount of a structure including an optical fiber sensor.

  While new social capital investment has been steadily progressing, social capital, which has been developed in the period of high growth, has been in operation for 30 to 40 years, and these safe and efficient maintenance management will continue in the future. It is a big issue.

  Already in the United States, large and small accidents and obstacles due to aging of bridges and highways have become a social problem since the 1990s, and the social capital has been maintained by numerous earthquake disasters such as the Northridge earthquake. There are many studies on management methods, and structural health monitoring is one of the promising applications (see, for example, Non-Patent Documents 1 and 2).

  Structural health monitoring is a technology that aims at detecting damaged parts and diagnosing the degree of deterioration based on information from sensors installed in the structure in advance. This is a combined technique of analysis techniques for appropriately processing data and deriving indexes of damage and deterioration (for example, see Non-Patent Document 3).

  Conventionally, however, the development of advanced sensors typified by optical fiber sensors and the development of sensor application methods for installing these sensors on structures have been the main. Therefore, whether structural health monitoring systems using these advanced sensors can provide useful information for social capital managers and users, such as damage detection and maintenance management, is developed. Need to be considered.

  On the other hand, civil engineering structures such as long-span bridges that are currently under construction are constructed on a large scale by various sensors and high-precision surveying for the purpose of safe and highly accurate construction management. Management is indispensable, and after completion, it is necessary to install some kind of monitoring system that supports long-term maintenance during operation. Since these were conventionally considered as separate systems, it was difficult to take over the structural performance during construction and immediately after completion (early in service), which is a very important index in long-term maintenance during operation.

  Therefore, if it is possible to build a structural monitoring system that can be consistently handled from construction management at the time of construction to maintenance of service applications, it is beneficial and effective for designers, installers, and managers. Can be used as a simple tool. In addition, the consistent system construction can open the way to the use of advanced sensors such as optical fiber sensors, which are difficult to introduce in terms of cost, regardless of advantages such as high performance and high durability.

  In this regard, the present inventor has already developed a long PC bridge structure health monitoring system mainly composed of optical fiber sensors (see, for example, Non-Patent Documents 4 and 5).

  In Non-Patent Document 5, optical fiber sensors are laid on the upper floor plate and lower floor plate of the main girder, and the main girder deflection curve (deflection amount) of the long-span bridge from the measured strain values above and below the main girder by this optical fiber sensor. Has been shown to seek. This is obtained by modeling the main girder as a continuous beam and sequentially reflecting the boundary conditions that change along the fastening and closing of the main girder and each tower due to construction progress.

K. P. Chong, N. J. Carino, G. Washer: Health Monitoring of civil Infrastructures, Smart Materials and Structures, Vol. 12, pp.483-493, 2003.05 A. Mita: Emerging Needs in Japan for Health Monitoring Technologies in Civil and Building Structures, Proceedings of Second Workshop on Structural Health Monitoring, pp. 56-67, 1999.09 Nobuo Takeda et al .: 1st-3rd Symposium on Intelligent Materials and Structural Systems, 1999.12, 2000.12, 2002.01 Hideaki Iwaki, Hiroshi Inada, Toshihiro Wakahara: “Monitoring during construction of a long cable stayed bridge using an optical fiber strain sensor (B-OTDR)”, 62nd Annual Lecture Meeting of Japan Society of Civil Engineers, pp. 805-806, September 2007 Hideaki Iwaki, Hiroshi Inada, Toshihiro Wakahara: “Development and application of monitoring system for long bridge” Prestressed Concrete, Vol. 50, No. 2, March 2008, Japan Prestressed Concrete Technology Association

  By the way, in the structural health monitoring system for a long-span bridge in the conventional non-patent document 5 described above, only a formula representing a deflection curve of a main girder at the very initial stage of the long-span bridge construction is shown. It is difficult to determine the amount of deflection at each stage of construction progress until completion.

  The present invention has been made in view of the above, and provides a method and apparatus for calculating a deflection amount of a structure including an optical fiber sensor capable of calculating the deflection amount of the structure according to the progress of the construction. For the purpose.

  In order to solve the above-described problems and achieve the object, a method for calculating the amount of deflection of a structure provided with an optical fiber sensor according to claim 1 of the present invention provides the amount of deflection of a structure provided with an optical fiber sensor. In the method of calculating based on the measured strain of the structure measured by the optical fiber sensor, the upper strain and the lower strain of the structure are measured by the optical fiber sensor and measured by the optical fiber sensor. The difference between the upper strain and the lower strain is divided by the height in the vertical direction of the structure to obtain a flexural curvature that defines the flexure amount, and the flexural curvature is 2 with respect to the horizontal direction of the structure. The basic deflection amount consisting of a mathematical formula including an arbitrary integration constant is obtained by integrating the number of times, and a boundary condition in a predetermined construction progress of the structure is applied to the basic deflection amount to obtain the value of the integration constant. Determined, characterized by calculating the amount of deflection at a given work progress of the structure on the basis of the basic deflection amount a value is substituted into the determined the constant of integration.

  According to a second aspect of the present invention, there is provided an apparatus for calculating a deflection amount of a structure including an optical fiber sensor, wherein the deflection amount of the structure including the optical fiber sensor is measured by the optical fiber sensor. In the apparatus for calculating based on the measured strain, the optical fiber sensor measures an upper strain and a lower strain of the structure, and the upper strain measured by the optical fiber sensor and the lower strain are measured. By dividing the difference from the side strain by the height in the vertical direction of the structure, a deflection curvature that defines the deflection amount is obtained, and the deflection curvature is integrated twice with respect to the horizontal direction of the structure to obtain an arbitrary integration constant. And determining a value of the integral constant by applying a boundary condition in a predetermined construction progress of the structure to the basic deflection amount, and determining the product Based on the basic deflection amount of the value of the constant is substituted, characterized in that to calculate the amount of deflection at a given work progress of the structure.

  According to a third aspect of the present invention, there is provided an apparatus for calculating a deflection amount of a structure including an optical fiber sensor according to the second aspect, wherein the structure is a bridge.

  According to a fourth aspect of the present invention, there is provided an apparatus for calculating a deflection amount of a structure including an optical fiber sensor according to the third aspect, wherein the bridge is a cable-stayed bridge.

  According to the present invention, in a method for calculating a deflection amount of a structure including an optical fiber sensor based on a measured strain of the structure measured by the optical fiber sensor, an upper strain and a lower side of the structure are calculated. The amount of deflection is defined by dividing the difference between the upper strain and the lower strain measured by the optical fiber sensor by the height in the vertical direction of the structure. And calculating the basic deflection amount comprising a mathematical formula including an arbitrary integration constant by integrating the deflection curvature twice with respect to the horizontal direction of the structure, and obtaining a predetermined deflection of the structure with respect to the basic deflection amount. The value of the integral constant is determined by applying boundary conditions in the construction progress, and the predetermined construction progress of the structure is determined based on the basic deflection amount to which the determined integral constant value is substituted. Because calculating the amount of deflection, there is an effect that it is possible to calculate the amount of deflection of the structure according to the construction progress.

FIG. 1 is a side view of a long PC cable stayed bridge as an application target example of the present invention. FIG. 2 is a configuration diagram of a structural health monitoring system including the calculation device of the present invention. FIG. 3 is a perspective view showing an optical fiber sensor. FIG. 4 is a configuration diagram of a strain measurement unit using an optical fiber sensor. 5A and 5B are perspective views showing a drawing process of the optical fiber sensor at the time of erection, where FIG. 5A is a view immediately after placing the main girder concrete, and FIG. 5B is a view after completion of the formwork movement and bar arrangement. FIG. 6 is a diagram illustrating an example of a strain measurement result. FIG. 7 is a flowchart showing an embodiment of a method for calculating a deflection amount of a structure including an optical fiber sensor according to the present invention. FIG. 8 is a diagram showing a coordinate system used for main girder deflection analysis. FIG. 9 is a diagram illustrating a deflection curve of the stage 1. FIG. 10 is a diagram illustrating a deflection curve of the stage 2. FIG. 11 is a diagram illustrating a deflection curve of the stage 3. FIG. 12 is a diagram illustrating a deflection curve of the stage 4. FIG. 13 is a diagram comparing the main girder deflection curves, where (a) is a comparison diagram with the survey level, and (b) is a comparison diagram with the design value.

  In the following, an embodiment of a method and apparatus for calculating the amount of deflection of a structure equipped with an optical fiber sensor according to the present invention will be described in detail with reference to the drawings taking the amount of deflection of a main PC cable stayed bridge main girder as an example. Note that the present invention is not limited to the embodiments.

  First, before explaining the deflection amount calculation method and apparatus of the present invention, a long-sized PC cable-stayed bridge in which an optical fiber sensor is laid will be explained.

  As shown in FIG. 1, the long PC cable-stayed bridge 1 is a bridge having a center span length of about 500 m, which is constructed by an overhanging construction method using a movable mold. The cable-stayed bridge 1 is substantially bilaterally symmetric with respect to the center CL of the span, and includes main towers P3 and P4 and piers A1, P1, P2, P5, and P6A. In construction using the construction method, for safe and highly accurate construction, over the entire construction period, the deformation of the structure due to formwork movement, concrete placement, slanting material tension, etc. is constantly grasped, and the production volume is managed. Therefore, deformation and vibration prediction during strong winds such as typhoons are important issues.

  For this reason, when erection, construction management mainly focuses on the management of alignment / volume in line with the progress of construction, the response to disturbances such as climate change during the construction period, and the response to vibrations (internal disturbances) that occur due to formwork movement. There is a need to do. On the other hand, in maintenance during operation after completion, the effects of creep, slack material tension relaxation, response to disturbances such as strong winds, response due to live loads of traveling vehicles, etc. are sequentially measured, and these are maintained and managed. Need to be an indicator.

  As shown in FIG. 2, an apparatus 100 for calculating the amount of deflection of a structure including an optical fiber sensor according to the present invention includes a structural health monitoring system 101 (hereinafter referred to as a system) that measures strain of a main beam 2 using an optical fiber sensor 10. It is prepared in). This system 101 is a system for transferring acquired strain data to a data center through the Internet, performing predetermined data processing, and storing the data on a server. Designers, managers, and the like can refer to and analyze measurement data from anywhere using the system 101 through a Web browser. The system 101 is installed on the main tower P3 side shown in FIG. 1 in consideration of the symmetry of the application target shown in FIG. The deflection amount calculation apparatus 100 according to the present invention operates using a CPU or a storage area included in a personal computer (personal computer) on the designer or manager side, and bends based on the received strain value. Calculate the quantity.

  An optical fiber sensor 10 (B-OTDR system: Brillouin Optical Time Domain Reflectometer) used in the system 101 is accompanied by propagation of pulse light in an optical fiber when pulse light having a very short period is incident along the axial direction of the optical fiber. The characteristic (backscattering) that a very small amount of light is reflected is used. Since the wavelength of the reflected light changes depending on the strain and temperature applied to the optical fiber, if the wavelength of the reflected light and the propagation time (the time from when the pulsed light is incident until the reflected light is received) are recorded, the light The entire fiber can be used as a strain sensor and temperature sensor.

Note that the accuracy (spatial resolution) in the length direction of strain and temperature that can be measured and the period (width) of the pulsed light incident on the optical fiber are inversely proportional to each other. The resolution is reduced. For example, when the period of incident pulse light is 10 nsec (10 × 10 ⁻⁹ sec), the spatial resolution is 1 m, and the measured value (strain / temperature) measured at a certain point is in the range of 0.5 m before and after that point. The average strain (temperature) value. The spatial resolution when the period is 100 ns is 10 m. Furthermore, since reflected light is very weak light, in actual measurement, pulsed light is repeatedly incident, and the reflected light is averaged to obtain strain / temperature. In addition to the period of the incident pulse light, the reception interval of the reflected light is changed to set the measurement interval (sampling interval).

  As shown in FIG. 3, the optical fiber sensor 10 is a strain sensor obtained by coating and reinforcing an optical fiber 4 with an embossed polyethylene resin 6 and an aramid fiber 8, as shown in FIG. Developed and applied as. In order to avoid the influence of stress from the outside of the sensor (side pressure or tension or compression due to adhesion) even when buried in concrete, it is possible to use a temperature sensor with an optical fiber strand inserted and protected in a stainless steel tube. .

  When laying the optical fiber sensor 10, a construction method is used in which the sensors are sequentially embedded in the four corners of the PC main beam 2 extending from the main tower P3 along the movable mold. That is, the start end (main tower P3 side) of each optical fiber sensor 10 embedded in the four corners of the main beam 2 is passed through the optical termination box 22 and the optical switch 12 from the beginning of sensor embedding as shown in FIG. It is connected to the measuring instrument 14 so as to be measurable, and the unembedded part and the terminal end of the sensor 10 are temporarily installed in the vicinity of the front end part of the bundle moving mold using the reel 16. Next, after the movement of the formwork and the arrangement of the main girder 2 are completed, the optical fiber sensor 10 is pulled out from the reel 16 and fixed along the reinforcing bar, and is embedded in the main girder 2 in accordance with the concrete placement. .

  4, the measuring instrument 14 and the personal computer 18 (personal computer), the optical switch 12 and the personal computer 18, the personal computer 18, the measuring instrument 14 and the hub 20 are connected to each other. If the CPU of the personal computer 18 has a margin, the deflection amount calculation device 100 may be incorporated in the personal computer 18 to calculate the deflection amount at the site and then send it to the designer or manager via the Internet. .

  An outline of the present construction method is shown in FIGS. By applying this method, continuous measurement is possible from the beginning to the completion of main girder extension, and the labor for sensor installation can be greatly reduced.

An example of main girder strain measurement results during erection is shown in FIG. In system 101, cycle 20n seconds incident pulsed light, average number of times ^{2 13} times of the reflected light is set measurement interval (sampling interval) and 0.5 m. That is, a strain value is obtained in 0.5 m increments in the entire laid optical fiber sensor, and each strain value is a strain average value in a range along the optical fiber sensor 1 m before and after the measurement point (2 m in total) ( Strain distribution).

  The measurement time required when the above measurement parameters are used is about several minutes per sensor. For this reason, it does not follow the strain change caused by vibration or impact. That is, the data obtained from the system 101 is a strain value obtained by a substantially static phenomenon.

  It should be noted that the time required to complete the measurement of all the optical fiber sensors connected to the optical switch is about one hour including the time required for switching the channel of the optical switch and storing the measurement data from each sensor. .

  Further, since the optical fiber sensor employed in the present system 101 is embedded at the time of concrete placement in accordance with the progress of construction at the site, two optical fiber strands are arranged in one sensor as compensation for breakage. The system is adopted (FIG. 3), and both strands are folded and fused at the reel tip, and the entire sensor is looped. For this reason, even if one optical fiber strand breaks at the time of placing concrete or the like, measurement can be performed without interruption by entering light in the opposite direction from the other one. Also in FIG. 6, the strain values are symmetrical with respect to the reel tip, indicating that both optical fibers in the sensor are in operation.

  In addition, the strain measurement using an optical fiber sensor has been carried out continuously every 2 days (during installation) to 4 hours (after completion) (6 to 12 times per day) from the beginning of system operation.

  It is very important for construction management to understand the distribution of main girder deflection at the time of erection. The main girder deflection curve (deflection amount) is calculated from the strain value obtained by the optical fiber sensor described above. The calculation of the amount of deflection is performed by the method or apparatus 100 for calculating the amount of deflection of the structure including the optical fiber sensor according to the present invention, which will be described in detail below.

  As shown in FIG. 7, in the method for calculating the amount of deflection of a structure including an optical fiber sensor according to the present invention, the upper strain value and the lower strain value of the main girder are measured by the optical fiber sensor (step S1) The boundary condition that changes with the progress of construction is reflected in the mathematical expression (basic deflection amount) representing the deflection curve of the main girder defined by the strain value (step S2). Then, the integral constant of the basic deflection amount is determined (step S3), and the deflection amount in the construction progress of the main girder is calculated based on the basic deflection amount into which the value of the integral constant is substituted (step S4). Become. The calculation apparatus 100 of the present invention performs this procedure by arithmetic processing using a computer.

  The mathematical expression (basic deflection amount) representing the deflection curve is a formula for calculating the deflection amount, and is obtained by dividing the difference between the upper strain and lower strain measured by the optical fiber sensor by the vertical height of the main girder. The obtained bending curvature is obtained by integrating twice with respect to the horizontal direction of the main girder, and includes an arbitrary integration constant.

  By applying the boundary conditions obtained in advance for each stage of construction progress to the mathematical expression representing the deflection curve including the integral constant, the deflection amount of the main PC cable stayed bridge main girder according to construction progress can be easily achieved. Can be calculated.

  Next, the process for deriving the calculation formula for the amount of deflection will be specifically described.

[Coordinate system and basic formula]
As shown in FIG. 8, a coordinate system is introduced in which the connecting portion between the main tower P3 and the main girder is the origin, the main span direction is the x axis, and the deviation from the main girder plan line is the y axis. The inclination angle θ is positive in the counterclockwise direction.
The basic equations for the main beam deflection curvature 1 / ρ and the inclination angle θ are:

The relationship between the deflection curvature and strain can be expressed by the following equation, where the distribution strain value of the main girder upper surface is ε _u , the distribution strain amount of the lower surface is ε _d , and the height of the main girder cross section is h: As shown.

  Substituting equation (3) into equation (1) and further integrating sequentially,

It becomes. The inclination angle θ and the deflection amount y of each point of the main girder can be obtained by obtaining the integration constants C ₁ and C ₂ in the equations (5) and (6) from the boundary conditions.

  Since the boundary condition changes due to the change in the support state accompanying the progress of the main girder construction, in this embodiment, the main girder is extended from one main tower P3 of the long PC cable-stayed bridge and the other main tower P4. The model is divided into four stages (stages 1 to 4) until the main girder is closed at the center, and the inclination angle and the amount of deflection are calculated. In the following calculation, in order to simplify the notation, the following definite integral is defined.

  That is, the basic formulas (5) and (6) are

  Can be written as:

[Deflection amount due to changes in main girder support status]
(Stage 1: Main girder extension BL00 to P2 connection)
First, a calculation formula for the deflection amount of stage 1 will be described.

  As shown in FIG. 9, the boundary condition in this stage 1 is only the constraint in the main tower P3, and is expressed by the following equation.

  Substituting Equations (11) and (12) into Equations (9) and (10), the integration constant is

  Is required. Therefore, the deflection curve under this condition (shown in bold in the figure)

  It becomes.

(Stage 2: P2 binding-before P1 closing)
Next, a calculation formula for the deflection amount of stage 2 will be described.

  As shown in FIG. 10, the boundary condition in this stage 2 is a constraint in P2 and the main tower P3, and is expressed by the following equation.

  Substituting Equations (16) and (17) into Equations (9) and (10), the integration constant is

  Is required. Therefore, the deflection curve under this condition is

  It becomes.

(Stage 3: P1 closing-before central closing)
Next, a calculation formula for the deflection amount of stage 3 will be described.

  Under the conditions of this stage 3, since the beam is indefinitely constant, as shown in FIG. 11, the beam is placed in two sections between P1 and P2 (point A to point B) and P2 to center (point B to center). Divide and introduce a virtual moment (unknown constant) and angle at P2 (point B).

<Stage 3-1: Continuous beam between P1 and P2 (point A to point B)>
The introduction of bending moments contribution as an unknown constant M ₂ in P2,

  It becomes. When equation (21) is integrated sequentially,

Note that the boundary condition in this case is constrained by P1 and P2, and when the inclination angle of the continuous beam at P2 is introduced as θ ₂ (an unknown constant),

  It becomes.

<Stage 3-2: Continuous beam from P2 to the center>
The bending moment contribution at P2 is considered to be equivalent to the above stage 3-1. Therefore, the deflection curve in this stage 3-2 can be expressed by the following three expressions.

Note that the boundary condition in this case is a constraint at P2 and P3, and the inclination angle of the continuous beam at P2 can introduce θ ₂ equivalent to the above stage 3-1, so that it is as follows.

<Stage 3-3: Coupling at P2>
In order to easily obtain the integral constant and the unknown constant in this stage 3-3, Expression (21) and subsequent expressions are expressed in a matrix.
Equations (22) and (23) are

  Similarly, equations (28) and (29) are

  It can be expressed as. Substituting the equations (24), (25), (26), (30), (31), and (32) representing the boundary conditions into the matrices (33) and (34),

  Can be written. The integral constant and the unknown constant are obtained by multiplying both sides of the matrix (35) by the inverse matrix of the sixth-order square matrix of the first term on the right side from the left. That is,

  Numerical calculation using a sweeping method or the like may be performed on the matrix (36).

(Stage 4: After closing the center)
Next, a calculation formula for the deflection amount of the stage 4 will be described.

  Since this stage 4 is an indeterminate beam as in the above stage 3, the main girder is between P1 and P2 (point A to point B) and between P2 and P3 (point B to point C) shown in FIG. , And divide the beam into three sections between P3 and P4.

<Stage 4-1: Between P1 and P2>
The governing equations and boundary conditions are the same as in stage 3-1. That is,

  It becomes.

<Stage 4-2: Between P2 and P3>
When the bending moment contributions at both ends in this condition are given as M ₂ and M ₃ respectively, the governing equation is

  It becomes. When equation (43) is integrated sequentially,

  It becomes. The boundary condition is

  It is.

<Stage 4-3: Between P3 and P4>
Only the unknown constant M ₃ of stage 4-2 contributes to the governing equation under this condition. Therefore,

  When equation (50) is integrated sequentially,

It becomes. The boundary condition is

  It is.

<Derivation of stage 4 integral and unknown constants>
Similar to the above stage 3, each governing equation is expressed in a matrix.
Equations (38) and (39) are

  Similarly, the equations (44) and (45) are

  Furthermore, the equations (51) and (52) are

It can be expressed as.
Expressions (40), (41), (42), (46), (47), (48), (49), (53), (54), and (55) representing boundary conditions are converted into a matrix (56), Substituting and organizing into (57) and (58),

  This can be numerically calculated in the same manner as in stage 3 above.

  By the method shown in the above stage 1 to stage 4, it is possible to derive a deflection curve accompanying the progress of construction of the main bridge girder in which the optical fiber distributed strain sensor is laid. Actually, since the distributed strain value obtained by the optical fiber distributed strain measuring instrument is, for example, a value of about 0.5 m intervals, numerical integration is performed using the unknown constant and the integral constant obtained by the above method. There is a need. In addition, when there is an unlaid section in which the optical fiber sensor is not laid in the main beam, the deflection curve of the unlaid section may be interpolated by an appropriate method.

  Next, a comparative example of a deflection curve calculated according to the present invention, a survey value, and a design value (theoretical value) will be described. FIGS. 13A and 13B are diagrams comparing the main girder deflection curves. FIG. 13A is a comparison diagram with the survey level, and FIG. 13B is a comparison diagram with the design value. The alignment after the oblique material tension of the previous construction step is shown as a reference value.

  FIG. 13 (a) is an example in which the deflection curve calculated by the calculation device 100 of the present invention is compared with the survey level (relative level value) based on the previous step diagonal material tension, and concrete from above. It is a figure about each construction step at the time of placement, a formwork movement, and diagonal material tension. The state of the main girder deflection curve obtained by the calculation device 100 from the strain value obtained from the optical fiber sensor 10 performing continuous measurement changes momentarily along the load change accompanying the progress of the construction step. I understand that. It can also be seen that the deflection curve (solid line) based on the measured strain value by the optical fiber sensor 10 and the survey level difference (black ▽) show a good relationship in each construction process.

  FIG. 13B shows a comparative example with the deflection amount (design value indicated by a circle) predicted in advance in the detailed design of the cable-stayed bridge. It can be seen that the deflection curve (solid line) based on the strain value measured by the optical fiber sensor 10 and the design value show a good relationship. As described above, the method of obtaining the deflection curve from time to time using the strain value obtained from the continuous measurement using the optical fiber sensor 10 is useful in performing the up-and-coming management of the next step.

  As described above, according to the present invention, in the method for calculating the amount of deflection of a structure including an optical fiber sensor based on the measurement strain of the structure measured by the optical fiber sensor, The upper strain and the lower strain are measured by the optical fiber sensor, and the difference between the upper strain and the lower strain measured by the optical fiber sensor is divided by the vertical height of the structure. The deflection curvature that defines the deflection amount is obtained, the deflection curvature is integrated twice in the horizontal direction of the structure to obtain a basic deflection amount including an arbitrary integration constant, and the basic deflection amount is determined. A value of the integral constant is determined by applying a boundary condition in a predetermined construction progress of the structure, and the value of the structure is determined based on the basic deflection amount into which the determined value of the integral constant is substituted. Because calculating the amount of deflection in the constant construction progress, it is possible to calculate the amount of deflection of the structure according to the construction progress.

  As described above, the method and apparatus for calculating the amount of deflection of a structure provided with the optical fiber sensor according to the present invention are useful for calculating the amount of deflection of the structure according to the progress of construction, and in particular, the amount of deflection. It is suitable for calculating the amount of flexure of structures such as bridges where the boundary condition for calculating the momentum changes with the progress of construction.

1 Long-span PC cable-stayed bridge 2 Main girder (structure)
DESCRIPTION OF SYMBOLS 4 Optical fiber 6 Polyethylene resin 8 Aramid fiber 10 Optical fiber sensor 12 Optical switch 14 Measuring instrument 16 Reel 18 Personal computer 20 Hub 22 Optical termination box 100 Deflection amount calculation apparatus of structure provided with optical fiber sensor 101 Structural health Monitoring system

Claims (4)

In the method of calculating the amount of deflection of the structure including the optical fiber sensor based on the measurement strain of the structure measured by the optical fiber sensor,
Measure the upper strain and lower strain of the structure with the optical fiber sensor,
Dividing the difference between the upper strain and the lower strain measured by the optical fiber sensor by the height in the vertical direction of the structure to obtain the deflection curvature that defines the deflection amount,
Integrating the deflection curvature twice with respect to the horizontal direction of the structure to obtain a basic deflection amount comprising a mathematical formula including an arbitrary integration constant;
Applying boundary conditions in the predetermined construction progress of the structure to the basic deflection amount to determine a value of the integral constant, and based on the basic deflection amount to which the determined value of the integral constant is substituted A method for calculating the amount of deflection of a structure having an optical fiber sensor, characterized by calculating the amount of deflection in a predetermined construction progress of the structure. In an apparatus for calculating the amount of deflection of a structure including an optical fiber sensor based on the measured strain of the structure measured by the optical fiber sensor,
The optical fiber sensor measures the upper strain and the lower strain of the structure,
Dividing the difference between the upper strain and the lower strain measured by the optical fiber sensor by the height in the vertical direction of the structure to obtain the deflection curvature that defines the deflection amount,
Integrating the deflection curvature twice with respect to the horizontal direction of the structure to obtain a basic deflection amount comprising a mathematical formula including an arbitrary integration constant;
Applying boundary conditions in the predetermined construction progress of the structure to the basic deflection amount to determine a value of the integral constant, and based on the basic deflection amount to which the determined value of the integral constant is substituted An apparatus for calculating a deflection amount of a structure provided with an optical fiber sensor, wherein the deflection amount of the structure in a predetermined construction progress is calculated.   The said structure is a bridge, The bending amount calculation apparatus of the structure provided with the optical fiber sensor of Claim 2 characterized by the above-mentioned.   The said bridge is a cable-stayed bridge, The bending amount calculation apparatus of the structure provided with the optical fiber sensor of Claim 3 characterized by the above-mentioned.

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