JP4077269B2 - Prestressed concrete structure monitoring system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a monitoring system for a prestressed concrete structure, and in particular, it is possible to accurately and economically and stably break a tendon used in a large prestressed concrete structure such as a road bridge or a railway bridge over a long period of time. The present invention relates to a monitoring system for prestressed concrete structures that can be monitored.
[0002]
[Prior art and problems]
For example, since concrete structures such as road bridges and railway bridges are subjected to repeated load over time, prestressed concrete structures in which tendons are embedded are used.
In such a prestressed concrete structure, it is very important to detect the breaking of the tendon because the collapse of the entire structure can be predicted in advance.
[0003]
Here, an acoustic emission (hereinafter abbreviated as AE) method has been conventionally known as a method for detecting breakage of a tension material embedded in a prestressed concrete structure.
This AE method is a method of diagnosing an abnormality in a concrete structure or the like by detecting an elastic wave generated by energy released when a solid is deformed or broken and analyzing the elastic wave.
[0004]
By this AE method, when trying to detect the breakage of the tendon material embedded in the prestressed concrete structure, most of the past, an AE sensor is installed in the vicinity of the site where the tendon material is embedded, A configuration is adopted in which the output of the AE sensor is guided by a cable to an AE measuring device including an amplifier, an A / D converter, a waveform recording device, and the like.
[0005]
However, when this configuration is applied to large prestressed concrete structures such as road bridges and railway bridges, the distance from the sensor to the measuring device becomes very long, and the signal is attenuated at the stage of propagation through the connection cable. However, there is a high possibility that the noise will become large and a misjudgment will be made.
In addition, the breakage of the tendon material embedded in the prestressed concrete structure needs to be monitored over a long period of time, and the configuration in which detection information of the sensor is always sent to the measuring device by a long cable increases the power consumption and the economy. Not right.
Furthermore, in order to stably monitor outdoor prestressed concrete structures such as road bridges and railway bridges over a long period of time, the monitoring system should be resistant to the effects of environmental loads such as wind and rain, changes in temperature, and vibration. It becomes important.
[0006]
Accordingly, an object of the present invention is to provide a prestressed concrete structure capable of accurately and economically and stably monitoring the breakage of tendon materials used in large prestressed concrete structures such as road bridges and railway bridges over a long period of time. The object is to provide an object monitoring system.
[0007]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention provides a sensor for detecting an elastic wave propagating in a prestressed concrete structure, a memory for storing data on the elastic wave detected by the sensor, and the sensor exceeds a reference value. A set of two measurement units each including a control unit that displays a warning when an elastic wave is detected and a communication port that outputs data relating to the elastic wave stored in the memory , and the measurement unit is prestressed. At least one set of two measurement units constituting a set on the surface of the concrete structure is installed at a predetermined interval, and between the two measurement units in each set installed on the surface of the prestressed concrete structure. When the sensor of one measurement unit detects an elastic wave exceeding the reference value, a signal is sent to the other measurement unit. Synchronized by means of the taken, and the data related to memory acoustic wave stored in each measurement unit and the monitoring system of the prestressed concrete structure which is configured to be appropriately collected via port for the communication.
[0008]
According to the prestressed concrete structure monitoring system according to the present invention described above, an elastic wave propagating through the prestressed concrete structure is detected in each of a plurality of measurement units installed on the surface of the prestressed concrete structure. Since the sensor and the memory for storing the data relating to the elastic wave detected by the sensor are provided, the data relating to the elastic wave detected by the sensor of each measurement unit is not attenuated and the noise is greatly reduced. In this state, it is stored in the memory of each measurement unit with high accuracy.
[0009]
And the monitoring system for the prestressed concrete structure according to the present invention described above, the elastic wave detected by the sensor of each measurement unit is a reference value, for example, an elastic wave exceeding the minimum value of the elastic wave based on the fracture of the tendon. When the sensor detects, the control unit of the measurement unit displays a warning, so the manager of the prestressed concrete structure can know the abnormality of the prestressed concrete structure from the warning display, and When the administrator of the prestressed concrete structure determines that there is a need for an investigation based on this warning display, the measurement unit that goes to the site and displays the warning display only in that case, and the measurement unit in the vicinity thereof For example, data relating to elastic waves stored in the memory in the It can be collected by using a Con.
[0010]
Further, in order to specify the breaking position of the tendon material from the data regarding the elastic wave stored in the memory of each measurement unit, each measurement unit is installed with a predetermined interval, and each measurement unit However, the prestressed concrete structure monitoring system according to the present invention described above is a set of two measurement units. One or more sets of two measurement units constituting a set on the surface of the prestressed concrete structure are installed at a predetermined interval, and two measurement units in each set installed on the surface of the prestressed concrete structure Since each of the two measurement units is synchronized with each other, the two measurement units constituting the synchronized set are separated by a predetermined interval. From the data on the feeding each memory acoustic wave stored in of, and breaking position of the tension member can be accurately identified. The synchronization between these two measurement units means that, for example, when the sensor of one measurement unit in the set detects an elastic wave exceeding a reference value, the other measurement unit in the set The monitoring system can be easily constructed by adopting a means such as transmitting a trigger signal, the entire system can be designed at a low cost and with a simple configuration, and is hardly affected by the environmental load.
[0011]
Here, in the prestressed concrete structure monitoring system according to the present invention, it is preferable that the two measurement units constituting the set are installed on the surface of the prestressed concrete structure in a state of being adjacent to each other with a gap between each other. .
In addition, the communication port of each measurement unit is connected, and one communication connector that can be connected to a personal computer or the like is installed at the end of the measurement unit. It is also preferable to be able to collect.
[0012]
The prestressed concrete structure referred to in the present invention is not particularly limited as long as it is a concrete structure in which a tendon is used, but there are bridges such as roads and railways, high-rise buildings, dams, and tunnels. Can be mentioned.
The sensor referred to in the present invention is a sensor that detects an elastic wave generated by energy released when a solid is deformed or broken, and includes an AE sensor, an ultrasonic sensor, an acceleration sensor, a microphone, and the like. .
Furthermore, the warning display performed in the present invention is not particularly limited in its method such as lighting of a warning light, warning sound generation, warning display on a monitor screen, and the like.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of the monitoring system for a prestressed concrete structure according to the present invention will be described in detail with reference to the drawings.
[0014]
FIG. 1 and FIG. 2 are diagrams conceptually showing an embodiment when the prestressed concrete structure monitoring system according to the present invention is applied to monitoring of a highway bridge.
[0015]
In FIG. 1, 1 indicates the entire bridge, 2 is a pier, 3 is a bridge girder passed between the piers 2 and 2, 4 is a concrete padded between the bridge girders 3 and 3, 5 is a paving concrete plate, 6 is a handrail.
The bridge girder 3 is a prestressed concrete structure in which a plurality of tension members 7 (only one is shown in FIG. 1) are embedded so as to withstand repeated load over time.
[0016]
As shown in FIGS. 1 and 2, a plurality (even number) of measurement units 10 are installed on the bridge girder 3 at appropriate intervals. Each of the measurement units 10 is installed in the vicinity of the portion where the tendon 7 is embedded, and as shown in FIG. 2, it is installed in the bridge girder 3 located in the vicinity of the pier 2 for easy maintenance. Has been. Further, two adjacent measurement units 10 are connected to each other by a cable K, and as shown in FIG. 3, the two measurement units 10 are configured into two measurement units 10A and 10B. The measurement units 10A and 10B are installed at a distance between the piers 2 and 2, for example, several tens of meters apart.
[0017]
As shown in FIG. 3, each of the measurement units 10 includes an AE sensor 11 that detects an elastic wave propagating in the bridge girder 3, an amplifier 12 that amplifies the output of the AE sensor 11, and an output of the amplifier 12 A filter 13 that removes environmental noise vibrations, an A / D converter 14 that digitizes an output that has passed through the filter 13, a control unit (for example, CPU) 15 that performs control described later, and the digitized elastic wave Memory (for example, flash memory) 16 for storing data, warning light connected to the control unit 15 (the warning light is 1 in three measurement units 10 provided in the same cross section as shown in FIG. Two warning lights are shared.) 17 and a trigger signal output port 18, an input port 19, and a communication port 20.
[0018]
The control unit 15 provided in the measurement unit 10 uses the constant value (for example, the data on the elastic wave based on the breakage of the tendon) as the reference value (for example, the data on the elastic wave detected by the AE sensor 11). If the elastic wave exceeding the reference value is detected by the AE sensor 11, the elasticity exceeding the reference value is immediately selected from the data relating to the elastic wave always stored in the memory 16. Instructs to store data relating to elastic waves in a predetermined time (for example, several tens of milliseconds) before and after the wave is detected, and controls to turn on the warning lamp 17, and the output port A trigger signal for synchronization is transmitted from 18 to the input port 19 provided in the other measurement unit 10B constituting the set via the cable K.
[0019]
The control unit 15 of the other measurement unit 10B that constitutes the set to which the trigger signal is transmitted has a memory 16 that constantly stores data on the elastic wave detected by the AE sensor 11 provided in the other measurement unit 10B. An instruction is given to store data relating to the elastic wave in the memory 16 for a predetermined time (for example, several tens of milliseconds) before and after the transmission of the trigger signal. Thereby, the data regarding the elastic wave based on the fracture | rupture of the tension material synchronized was preserve | saved in each memory 16 of the two measurement units 10A and 10B which comprise a group.
[0020]
The manager of the concrete structure can know the abnormality of the bridge 1 on the expressway from the lighting of the warning light 17, and if it is determined that the investigation is necessary based on the warning display, Collecting data related to elastic waves stored in the memory 16 from the measuring unit 10A, the measuring unit 10A, and the measuring unit 10B as a set thereof, using the personal computer or the like via each communication port 20 Then, by analyzing the collected data on the elastic wave, the breaking position and the breaking scale of the tension member 7 in the bridge 1 of the highway are specified.
[0021]
The monitoring system for a prestressed concrete structure according to the present invention having the above-described configuration monitors the bridge 1 of the highway with the flow as described above.
[0022]
As mentioned above, although one embodiment of the prestressed concrete structure monitoring system according to the present invention has been described, the present invention is not limited to the above-described embodiment, and within the scope of the technical idea of the present invention. Of course, various modifications and changes are possible.
[0023]
For example, in the above-described embodiment, as a configuration in which two measurement units 10A and 10B are synchronized, when one measurement unit 10A detects an elastic wave exceeding a reference value, the other measurement unit Although the trigger signal for synchronizing with 10B is transmitted via the input / output ports 18 and 19, the configuration is not limited to this configuration, and various known configurations can be adopted as a configuration for achieving synchronization between the two parties. .
[0024]
In the above-described embodiment, the communication port 20 of each measurement unit 10 and the warning lamp 17 for displaying a warning are described separately. However, as shown in FIG. The communication port 20 of the unit 10 is connected using, for example, a system such as RS-485, and a warning is displayed by displaying the position on one monitor screen 21 and is stored in the memory 16 of each measurement unit 10. A configuration may be adopted in which data relating to elastic waves is collected using the personal computer 23 via one connected communication connector 22.
[0025]
Further, in the above-described embodiment, the case where the monitoring system according to the present invention is applied to the monitoring of the bridge 1 on the expressway has been described. However, the monitoring system according to the present invention is not limited to the bridges, high-rise buildings, dams of other railways. It can be suitably used for monitoring various large prestressed concrete structures using tendons such as tunnels.
[0026]
【The invention's effect】
As mentioned above, according to the monitoring system of the prestressed concrete structure concerning this invention demonstrated above, the system which can monitor the fracture | rupture of the tension material currently used for the prestressed concrete structure accurately, economically and stably over a long period of time. There is an effect.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view conceptually showing an embodiment when a prestressed concrete structure monitoring system according to the present invention is applied to monitoring of a highway bridge.
FIG. 2 is a side view conceptually showing an embodiment when a prestressed concrete structure monitoring system according to the present invention is applied to monitoring of a highway bridge.
FIG. 3 is a block diagram of a measurement unit constituting a monitoring system for a prestressed concrete structure according to the present invention.
FIG. 4 is a block diagram showing the whole prestressed concrete structure monitoring system according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Bridge 2 Bridge pier 3 Bridge girder 4 Filling concrete 5 Pavement concrete board 6 Rail 7 Tensile material 10 Measurement unit 11 AE sensor 12 Amplifier 13 Filter 14 A / D converter 15 Control part 16 Memory 17 Warning light 18 Output port 19 Input port 20 Communication Port 21 monitor screen 22 communication connector 23 PC K cable

Claims (1)

A system for monitoring breakage of a tendon material embedded in a prestressed concrete structure, the sensor detecting an elastic wave propagating through the prestressed concrete structure, and a memory for storing data relating to the elastic wave detected by the sensor And two measurement units each including a control unit that displays a warning when the sensor detects an elastic wave exceeding a reference value, and a communication port that outputs data relating to the elastic wave stored in the memory. One set is set, and the measurement unit is installed on the surface of the prestressed concrete structure, and at least one set of two measurement units constituting the set is placed at a predetermined interval. Yue the sensor reference value of one of the measuring units between two measuring units in each set That synchronized by means for transmitting the other signals to the measurement unit when it detects the acoustic wave is taken, and so that data on the memory acoustic wave stored in each measurement unit can be appropriately collected via port for the communication A monitoring system for prestressed concrete structures, characterized in that

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