JP2005043220A - Sensor and method for monitoring crack in concrete structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor for monitoring a crack, which directly checks the width of the crack in a concrete structure, and to provide a method for monitoring the crack in the concrete structure, which detects an increase in the width of the crack in real time by using the sensor and can properly send information such as caution, danger or the like to a keeper of the structure in accordance with states of the structure. <P>SOLUTION: A plurality of conductive metal plates 2 are arranged on a rubber plate 1 so that the metal plates 2 overlap each other by an overlap value w in accordance with the width of the crack. When the rubber plate 1 is extended more than the overlap value w of the metal plates 2, the occurrence of the crack having the width equal to the overlap value of the metal plates 2 can be detected. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a crack monitoring sensor for a concrete structure, a manufacturing method thereof, and a crack, which detects the crack width of the concrete structure and provides an appropriate response information corresponding to the situation to the manager of the concrete structure. It relates to the monitoring method.

Since concrete, such as tunnels and viaducts, cracks in the concrete due to deterioration and may lead to a serious accident, monitoring is conducted to monitor the cracks in the concrete. Therefore, as a concrete crack monitoring device, conventionally, an optical fiber is embedded in the concrete surface to monitor the crack. As an example of using an optical fiber, if the light passing through the optical fiber is bent, the light leaks to the outside and the intensity of the light passing through the fiber is reduced. Etc. are known. However, the method of monitoring the position of the crack by cutting the optical fiber has a problem that if the fiber is cut, the subsequent monitoring cannot be performed, and the cost of the optical fiber is high.

In addition, monitoring of the cracks in the concrete with a strain gauge embedded in the concrete is also performed, but this strain measurement method is limited in the measurement position and the measurement accuracy is too high. Therefore, there is a drawback that it is difficult to be a judgment criterion.

Therefore, the conventional method for monitoring cracks in concrete is to install one kind or two or more kinds of electrically conductive materials having different elongation properties on the surface or inside of the concrete via an insulating material, and the electrical conductivity of the material. , And the outline of the crack occurrence and the width of the crack is detected due to the loss of electrical conductivity, or the surface of the concrete or the inside of the crack is crossed over the cracks that have already occurred. There are two or more different types of electrically conductive materials installed via an insulating material, the electrical conductivity of the material is measured, and the change in cracking is monitored by the loss of electrical conductivity. Yes (see, for example, Patent Document 1)
JP 2002-257769 A

However, in the above-described known invention, the tendency of whether or not cracks are increasing can be seen, but the value of crack width itself has not been found.

In addition, conventional crack monitoring sensors for concrete structures predict the crack width from changes in electrical resistance, and the absolute value of cracks in the concrete structure cannot be directly confirmed.

The present invention provides a crack monitoring sensor for directly confirming the crack width of a concrete structure, and the detection of the crack width of a concrete structure that can detect the increase in the crack width of the concrete structure in real time using the sensor. Method and
Depending on the condition of the concrete structure, for example, when concrete may fall due to the occurrence of a crack, there is a possibility that it may lead to personal injury at a tunnel or viaduct in an urban area, but there is a possibility of personal injury at a sea pier. Provide a method for monitoring cracks in concrete structures that can appropriately convey information such as cautions and dangers to the manager of the concrete structures according to the low situation.

According to the present invention, a plurality of conductive metal plates are overlapped with each other in accordance with the width of the concrete crack to be detected on the material that extends following the crack of the concrete attached to the surface of the concrete structure. From the sensor for monitoring cracks in the concrete structure that detects the increase in cracks in the overlap width of the metal plate when the material that extends following the cracks in the concrete extends longer than the overlap length of the metal plate In the manufacturing method, a material that extends following the cracks of the concrete is stretched in advance by the overlap width of a plurality of metal plates, and a part of each metal plate is pasted thereon and arranged in a plane, and then the concrete Release the extension of the material that extends following the crack and overlap each metal plate Prepared by.

According to the monitoring method of the present invention, according to various situations in which the concrete structure is placed, the crack increasing width determined to be caution or danger is determined, and the sensor for detecting the crack increasing width is detected on the surface of the concrete structure. This is done by providing the manager of the concrete structure via the Internet or packet communication with a mobile phone, etc., with information such as cautions and dangers corresponding to the increased width of cracks obtained by mounting and measuring the sensor.

The monitoring sensor of the present invention can directly check and monitor the crack width of a concrete structure. Furthermore, the crack width can be confirmed more effectively if used in combination with a sensor that predicts the crack width based on the change in electrical resistance.

In addition, according to the crack monitoring method of the present invention, the amount of increase in the crack width of the concrete structure is detected in real time, and information such as cautions and dangers of the concrete structure is obtained according to the state of the structure. It can be communicated appropriately to the administrator.

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an arrangement side view of a crack monitoring sensor for a concrete structure according to the present invention, and FIG. 2 is an enlarged side view of an essential part of an arrow A portion in FIG.

First, the crack monitoring sensor is made of copper, on a rubber plate 1 rolled in a unit of several tens of meters in a tape shape with a thickness of about 1.0 mm and a width of 20 mm attached to the surface of a cracked concrete structure. A plurality of metal plates 2 having conductivity such as tin and solder and having a low contact resistance are arranged so as to overlap each other as indicated by w according to the width of cracks in the concrete to be detected. .

Instead of the rubber plate 1, a material that extends following cracks in the concrete, for example, a plastic, a nonwoven fabric, or a woven fabric having a thickness t <0.2 mm may be used.

When the rubber plate 1 extends beyond the length of the overlap w of each metal plate 2 described above, it becomes possible to detect the occurrence of cracks in the wrap width of the metal plate 2 because the electric resistance becomes infinite. Yes.

In the crack monitoring sensor having the above-described configuration, if the concrete cracks to be detected are, for example, two stages of 0.5 mm and 1.0 mm, the overlap w of the metal plate 2 is 0.5 mm; What is 0 mm is placed on the same rubber plate 1 or another rubber plate 1 not shown.

The length of the metal plate 2 is appropriately set within a range of about 5 to 20 mm, and the rubber plate 1
It is preferable that the range of the adhesion part is 2 mm or less.

As a method of taking the overlap w of each metal plate 2 of the above-described sensor, the rubber plate 1 is stretched in advance by a width for overlapping the rubber plate 1, and the metal plate 2 such as a copper plate is not laminated on the flat plate in order. The metal plates 2 can be overlapped with each other with a predetermined width w if the rubber plates 1 are adhered and pasted together, and then the rubber plates 1 are loosened and returned to their original positions. At that time, the size of the wrap w can be set by the extent to which the rubber plate 1 is stretched.
. It can be 5 mm or more.

When the rubber plate 1 extends beyond the length of the overlap w of the metal plate 2 by attaching the above sensor to the surface of the concrete structure, the electric resistance becomes infinite and the crack of the lap width of the metal plate 2 increases. Can be detected.

Next, the crack monitoring method for concrete structures determines the crack increase width that is judged as dangerous or caution according to various situations where the concrete structure is placed, and the surface of the concrete structure depends on the crack increase width. Attach the sensor wrapped with a metal plate and set the electrical resistance value (calculated from the voltage and current) of the sensor of Fig. 1 and Fig. 2 installed on the concrete structure at every predetermined time (can be set at any time) Is measured and the time at that time is stored in the computer.

Further, at predetermined intervals, the data stored in the computer is sent to a computer that determines the cracking status by packet communication using a mobile phone or the Internet.
Note that a solar panel may be installed as a necessary power source in the place where these computer structures are located when there is no power source from an electric power company.

The computer that determines the cracking condition detects that when the electrical resistance of the sensor has become infinite, it detects that the crack of the overlap width of the sensor has increased,
The state is sent over the Internet to a computer held by the administrator of the computer structure in accordance with a criterion corresponding to the increased width of the crack. It is also possible to send the state by packet communication to the cellular phone of the concrete structure manager.

The sensor of the present invention described above can directly monitor the crack width, which has been impossible in the past. Furthermore, when used in combination with a sensor that predicts the crack width from the change in electrical resistance, it is effective because the crack width can be confirmed.

It is an arrangement | positioning side view in one Example of the sensor for crack monitoring of this invention. It is a principal part expanded side view of the arrow A part of FIG.

Explanation of symbols

1 Rubber plate 2 Metal plate w Overlap

Claims (3)

  A plurality of conductive metal plates are placed on top of the material that follows the cracks in the concrete attached to the surface of the concrete structure, overlapping each other according to the width of the concrete crack to be detected, A sensor for monitoring cracks in a concrete structure that detects an increase in cracks in the overlap width of a metal plate when the material that stretches following the cracks in the concrete exceeds the overlap length of the metal plate.   A material that stretches following the cracks of concrete in advance by the overlap width of multiple metal plates, pastes a part of each metal plate on it and arranges it in a flat shape, and then extends a material that follows the cracks of concrete The method for manufacturing a crack monitoring sensor for a concrete structure according to claim 1, wherein the metal plates are overlapped by releasing the extension.   The sensor according to claim 1, wherein a crack increasing width to be determined as caution or danger is determined according to various situations in which the concrete structure is placed, and the crack increasing width is detected on the surface of the concrete structure. A method for monitoring cracks in a concrete structure that provides information such as cautions and dangers corresponding to the increase in cracks obtained by sensor measurements to the manager of the concrete structure via the Internet or packet communication via a mobile phone.

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