JP2004061432A - Monitoring system of prestressed concrete structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system for precisely, economically and stably monitoring the breakage of tendons used for a large-sized prestressed concrete structure such as a bridge for an expressway over a long period of time. <P>SOLUTION: The monitoring system comprises one or more sets of measuring units in the state that two sets of the measuring units are at a prescribed interval composing on the surface of a structure one set of the two measuring units provided with a sensor for detecting an elastic wave propagating the inside of the structure; a memory for storing data concerning the elastic wave detected with the sensor; a control part for performing alarm display in the case that the sensor detects the elastic wave exceeding a reference value; and a communication port for outputting the data concerning the elastic wave stored in the memory, synchronizes with each other between the two measuring units in each set installed on the surface of the structure, and can properly collect the data concerning the elastic wave stored in the memory of each measuring unit through the communication port. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a monitoring system for a prestressed concrete structure, and more particularly, 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 for a long time. The present invention relates to a monitoring system for a prestressed concrete structure that can be monitored.
[0002]
[Prior art and its problems]
For example, a concrete structure such as a road bridge or a railway bridge receives a repeated load over time, and therefore a prestressed concrete structure in which a tendon is embedded is used.
In such a prestressed concrete structure, it is very important to detect the breakage of the tendon since 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 or the like of a tendon buried in a prestressed concrete structure.
The AE method is a method of detecting an elastic wave generated by energy released when a solid is deformed or broken, and analyzing the elastic wave to diagnose an abnormality of a concrete structure or the like.
[0004]
When it is intended to detect the breakage of the tendon buried inside the prestressed concrete structure by the AE method, most of the past, an AE sensor is installed near the portion where the tendon is buried, A configuration is adopted in which the output of the AE sensor is led by a cable to an AE measuring device having a built-in amplifier, A / D converter, 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 attenuation during the propagation of the connecting cable In addition, there is a great possibility that noise will increase and an erroneous judgment will be made.
Further, it is necessary to monitor the breaking of the tendon buried in the prestressed concrete structure for a long period of time. Not a target.
Furthermore, in order to monitor outdoor prestressed concrete structures such as road bridges and railway bridges stably over a long period of time, a monitoring system that is not easily affected by environmental loads such as wind and rain, changes in temperature, and vibrations. It becomes important.
[0006]
Therefore, an object of the present invention is to provide a prestressed concrete structure capable of accurately and economically and stably monitoring the breaking of a tendon used for a large prestressed concrete structure such as a road bridge or a railway bridge for a long time. An object of the present invention is to provide an object monitoring system.
[0007]
[Means for Solving the Problems]
In order to achieve the above 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 exceeding a reference value. A pair of measurement units each including a control unit for displaying a warning when an elastic wave is detected, and a communication port for outputting data relating to the elastic wave stored in the memory are provided on the surface of the prestressed concrete structure. At least one set of two measurement units constituting a set is installed at a predetermined interval, and the two measurement units in each set installed on the surface of the prestressed concrete structure are synchronized with each other, and The structure is such that data on elastic waves stored in the memory of each measurement unit can be appropriately collected via the communication port. And the monitoring system of prestressed concrete structures was.
[0008]
According to the monitoring system for a prestressed concrete structure according to the present invention described above, each of the plurality of measurement units installed on the surface of the prestressed concrete structure detects an elastic wave propagating in the prestressed concrete structure. Since the sensor and the memory for storing the data on the elastic waves detected by the sensor are provided, the data on the elastic waves detected by the sensors of the respective measurement units are not attenuated and the noise is significantly reduced. In this state, the data is accurately stored in the memory of each measurement unit.
[0009]
Then, the monitoring system of 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 breaking of the tendon material. When the sensor detects, the control unit of the measurement unit performs a warning display, so that the administrator of the prestressed concrete structure can know the abnormality of the prestressed concrete structure from the warning display, and If the manager of the prestressed concrete structure determines that there is a need for an investigation based on the warning message, the person goes to the site only in that case, and the measuring unit on which the warning message is displayed, and the measuring unit in the vicinity thereof Data on the elastic waves stored in the memory, for example, via a communication port. It can be collected by using a Con.
[0010]
Further, in order to specify the breaking position of the tendon material from the data on the elastic waves stored in the memory of each measurement unit, each measurement unit is installed at a predetermined interval, and each measurement unit is It is necessary that the data of the pre-stressed concrete structure according to the present invention is synchronized or fixed in time, that is, synchronized. Are installed on the surface of the prestressed concrete structure at least one set of two measuring units at a predetermined interval, and two measuring units in each set installed on the surface of the prestressed concrete structure Since each of them is synchronized between the two measurement units, the predetermined intervals are provided and the two measurement units constituting the synchronized set are separated. From the data on the feeding each memory acoustic wave stored in of, and breaking position of the tension member can be accurately identified. Synchronization between the two measurement units is performed, for example, when the sensor of one of the measurement units detects an elastic wave exceeding a reference value, and the other measurement unit of the pair. By adopting such means as transmitting a trigger signal to the monitoring system, the monitoring system can be easily constructed, the whole system can be designed at a low cost and a simple configuration, and the monitoring system is hardly affected by an environmental load.
[0011]
Here, in the monitoring system for a prestressed concrete structure 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 where they are adjacent to each other with an interval. .
In addition, the communication port of each measurement unit is connected, one communication connector that can be connected to a personal computer or the like is installed at the end, and a personal computer or the like is connected to the communication connector as needed to transfer the data of each measurement unit. It is also preferable to be configured to be able to collect.
[0012]
In addition, the prestressed concrete structure referred to in the present invention is not particularly limited as long as it is a concrete structure using a tendon, but bridges such as roads and railways, high-rise buildings, dams, tunnels, and the like are included. No.
The sensor according to 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. .
Further, the warning display performed in the present invention is not particularly limited, such as turning on a warning light, issuing a warning sound, and displaying a warning on a monitor screen.
[0013]
BEST MODE FOR CARRYING OUT 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]
1 and 2 are diagrams conceptually showing an embodiment in which the monitoring system for a prestressed concrete structure according to the present invention is applied to monitoring of a bridge on an expressway.
[0015]
In FIG. 1, 1 indicates the entire bridge, 2 indicates a pier, 3 indicates a bridge girder spanned between the piers 2 and 2, 4 indicates a filling concrete filled between the bridge girder 3 and 3, 5 indicates a paved concrete plate, Reference numeral 6 denotes a row.
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 loads over time.
[0016]
As shown in FIGS. 1 and 2, a plurality (even number) of measurement units 10 are provided at appropriate intervals in the bridge girder 3. Each of the measuring units 10 is installed near a portion where the tendon 7 is embedded, and as shown in FIG. 2, installed on a bridge girder 3 located near the pier 2 to facilitate maintenance. Have been. In addition, two adjacent measurement units 10 are connected to each other by a cable K, and as shown in FIG. 3, are configured as a set of two measurement units 10A and 10B. The measurement units 10A and 10B are installed just apart from the piers 2 and 2, for example, several tens of meters.
[0017]
As shown in FIG. 3, each of the measurement units 10 includes an AE sensor 11 for detecting an elastic wave propagating in the bridge girder 3, an amplifier 12 for amplifying the output of the AE sensor 11, and an output of the amplifier 12. , An A / D converter 14 for digitizing an output passing through the filter 13, a control unit (for example, CPU) 15 for performing control described later, and a digital elastic wave. A memory (for example, a flash memory) 16 for storing data, a warning light connected to the control unit 15 (the warning light is one of three measurement units 10 provided on the same cross section as shown in FIG. 1) 17 and a trigger signal input port 18, an output port 19, and a communication port 20.
[0018]
The control unit 15 provided in the measurement unit 10 constantly converts the data regarding the elastic wave detected by the AE sensor 11 into a reference value (for example, the data regarding the elastic wave based on the breaking of the tendon material) in a comparator (not shown). If the elastic wave exceeding the reference value is detected by the AE sensor 11, the elastic wave exceeding the reference value is immediately read from the data on the elastic wave constantly stored in the memory 16. An instruction to store data on elastic waves for a predetermined time (for example, several tens of msec) before and after the wave is detected in the memory 16, control to turn on the warning lamp 17, and the output port A trigger signal for synchronizing is transmitted from 18 via a cable K to an input port 19 provided in the other measuring unit 10B constituting the set.
[0019]
The control unit 15 of the other measurement unit 10B constituting the set to which the trigger signal has been transmitted is transmitted to the memory 16 that constantly stores data on the elastic waves detected by the AE sensor 11 provided in the other measurement unit 10B. An instruction is given to store data on the elastic wave in the memory 16 for a predetermined time (for example, several tens of msec) before and after the time when the trigger signal was transmitted. As a result, the data on the elastic waves based on the fracture of the synchronized tendon material is stored in the memories 16 of the two measurement units 10A and 10B constituting the set.
[0020]
Then, the administrator 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, the manager is notified to the site. The data on the elastic waves stored in the memory 16 is collected from the measurement unit 10A on which the outgoing message and the warning display are made and the measurement unit 10B as a pair using the personal computer or the like via each communication port 20. Then, by analyzing the collected data on the elastic waves, the breaking position, the breaking scale, and the like of the tendon 7 on the bridge 1 on the expressway are specified.
[0021]
The monitoring system for a prestressed concrete structure according to the present invention having the above-described configuration monitors the highway bridge 1 with the flow described above.
[0022]
As described above, one embodiment of the monitoring system for a prestressed concrete structure according to the present invention has been described. However, the present invention is not limited to the above-described embodiment, and is 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 embodiment, the configuration is such that synchronization is established between the two measurement units 10A and 10B. When one measurement unit 10A detects an elastic wave exceeding a reference value, the other measurement unit Although a trigger signal for synchronizing with 10B is transmitted via the input / output ports 18 and 19, the present invention is not limited to this configuration, and various known configurations can be adopted as a configuration for achieving synchronization between the two parties. .
[0024]
Further, in the above-described embodiment, the configuration in which the communication port 20 of each measurement unit 10 and the warning lamp 17 for displaying a warning are independently provided has been described. 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 display is performed by a position display on one monitor screen 21 and stored in the memory 16 of each measurement unit 10. It is also possible to adopt a configuration in which data regarding elastic waves is collected using a personal computer 23 via one connected communication connector 22.
[0025]
Furthermore, in the above embodiment, the case where the monitoring system according to the present invention is applied to the monitoring of the bridge 1 on the highway has been described. However, the monitoring system according to the present invention is also applicable to other railway bridges, high-rise buildings, and dams. It can be suitably used for monitoring various large-sized prestressed concrete structures using a tendon such as a tunnel.
[0026]
【The invention's effect】
According to the monitoring system for a prestressed concrete structure according to the present invention described above, a system capable of accurately, economically, and stably monitoring the breakage of a tendon used in a prestressed concrete structure over a long period of time. The effect is as follows.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view conceptually showing an embodiment in which a monitoring system for a prestressed concrete structure according to the present invention is applied to monitoring of a highway bridge.
FIG. 2 is a side view conceptually showing an embodiment in which the monitoring system for a prestressed concrete structure according to the present invention is applied to monitoring of a bridge on an expressway.
FIG. 3 is a block diagram of a measuring unit constituting the monitoring system for a prestressed concrete structure according to the present invention.
FIG. 4 is a block diagram showing an entire monitoring system for a prestressed concrete structure according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Bridge 2 Bridge pier 3 Bridge girder 4 Filling concrete 5 Paving concrete plate 6 Railing 7 Tendon 10 Measurement unit 11 AE sensor 12 Amplifier 13 Filter 14 A / D converter 15 Control unit 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, comprising: a sensor for detecting an elastic wave propagating in the prestressed concrete structure; and a memory for storing data on the elastic wave detected by the sensor. And a control unit for displaying a warning when the sensor detects an elastic wave exceeding a reference value, and a communication port for outputting data relating to the elastic wave stored in the memory. At least one set of two measuring units constituting a set is provided at a predetermined interval on the surface of the prestressed concrete structure, and two units of each set are set on the surface of the prestressed concrete structure. The elastic waves stored in the memory of each measurement unit are synchronized with each other between the measurement units. The chromatography data and characterized by being configured so as to be suitably collected via port for the communication, the monitoring system of the prestressed concrete structure.

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