KR102337770B1 - Dignosis method by apparatus of steel bar cracking - Google Patents

Abstract

The present invention relates to an apparatus for diagnosing rebar breakage, by locating the magnetic sensor 7 at a certain height above the ground surface 2 of the concrete pole 1 and moving the magnetic sensor 7 in the circumferential direction of the concrete pole 1 Measuring the magnetic field while rotating, diagnosing whether the reinforcing bar is broken using the measured magnetic field, and placing the magnetic sensor at a certain height of the structure located above the ground surface in a structure in which rebar is embedded inside such as a concrete pole, and this magnetic sensor After measuring the magnetic field by rotating it in the circumferential direction, there is an advantage in that it can be easily diagnosed at a remote location above the surface of the earth whether the reinforcing bar below the earth's surface is broken by comparing the relative magnetic field strength and magnetic flux density.

Description

Diagnosis method by rebar fracture diagnosis device {DIGNOSIS METHOD BY APPARATUS OF STEEL BAR CRACKING}

The present invention relates to a diagnosis method by a rebar fracture diagnosis device, and more particularly, to a diagnosis method by a rebar fracture diagnosis device for diagnosing rebar fracture in a structure in which rebar is embedded in a concrete electric pole or the like.

Most of the supports used for distribution lines are concrete poles and have a prestressed (P.S) concrete structure. P.S Concrete collapsing accidents occur due to the fact that the reinforcing bars inside the poles are broken when the concrete poles are used for a long time.

P.S Since the concrete structure is designed to support the bending moment with the tensile force of the rebar, if the rebar inside the pole is broken and the tensile force is lost, the concrete collapses.

Recently, when a worker cut the cable connected to the pole to replace the concrete pole, the balance of power was broken and the pole suddenly collapsed, resulting in a safety accident.

In Korea, where P,S concrete poles are used, there is a very high risk of accidents due to breakage of reinforcing bars inside concrete because various devices such as communication lines and transformers are installed on the poles. Therefore, it is necessary to diagnose the breakage of reinforcing bars in concrete by a non-destructive method and replace or reinforce the poles before the collapse accident occurs.

As a related prior patent, there is KR 10-2014-0042240 (published on April 7, 2014).

However, the prior patent is a method of diagnosing the fracture site of rebar in a concrete pole using a sensor, which is one of the functions of a smartphone. have.

That is, as shown in (a) of Figure 1, when the reinforcing bar break (3) occurs at the top of the ground surface (2) of the concrete pole (1), the sensor is contacted with the concrete pole (1) to diagnose whether the rebar breaks. However, as shown in (b) of FIG. 1, when the reinforcing bar break 5 occurs in the lower part of the ground surface 2 of the concrete pole 1, the contact of the sensor is impossible, so the diagnosis of the rebar break is impossible.

An object of the present invention is to provide a reinforcing bar break diagnostic device capable of diagnosing reinforcing bar breakage in a non-destructive method in a structure in which reinforcing bars are embedded inside, such as a concrete electric pole, and enabling diagnosis of whether or not the rebar below the ground surface is broken from a remote location above the ground surface.

According to a feature of the present invention for achieving the object as described above, in the apparatus for diagnosing the breakage of reinforcing bars embedded in a concrete pole, a magnet for magnetizing the reinforcing bars embedded in the interior of the concrete pole, the ground surface of the concrete pole It consists of a magnetic sensor that measures the magnetic field of the reinforcing bar embedded in the concrete pole while rotating along the circumferential direction of the concrete pole on which the magnetized reinforcing bar is located at a certain height of the upper part, and the magnet is 50 mm above the ground surface and Rotating the magnet in the circumferential direction of the concrete pole on the ground surface with respect to the reinforcing bar in the lower 50mm area to magnetize the reinforcing bar, and using the magnetic field measured by the magnetic sensor at a certain position above the ground surface of the concrete pole From the difference in the relative magnetic field strength by comparing the measured magnetic flux densities in each circumferential direction, the fracture location and the fracture location of the rebar buried under the ground surface are diagnosed at a remote location above the ground surface, and the magnetic sensor expresses the measured magnetic field on the time axis to compare the relative magnetic field strength to diagnose whether the reinforcing bar is broken, and the magnetic sensor expresses the measured magnetic field as a distance axis and compares the relative magnetic field strength to diagnose whether the reinforcing bar is broken.
Further, in the diagnosis method by the rebar breakage diagnosis apparatus, rotating the magnet in the circumferential direction of the concrete pole and magnetizing the reinforcing bar embedded in the concrete pole;
Positioning the magnetic sensor at a certain height of the structure located above the ground surface of the concrete pole, and rotating the magnetic sensor along the circumferential direction of the concrete pole where the magnetized reinforcing bar is located, the magnetic field of the reinforcing bar embedded in the concrete pole measuring; and
Including the step of diagnosing whether the reinforcing bar is broken using the measured magnetic field,
The step of magnetizing the reinforcing bar includes magnetizing the reinforcing bar while rotating the magnet in the circumferential direction on the ground surface with respect to the reinforcing bars in the 50 mm and lower 50 mm regions above the ground surface,
The step of diagnosing whether the reinforcing bar is broken is to compare the magnetic flux densities in each circumferential direction measured at a certain location on the upper surface of the concrete pole, and determine whether or not the reinforcing bar embedded in the lower part of the ground is fractured and the fracture location from the difference in the relative magnetic field strength. Diagnosis at a remote location above the surface of the earth,
The magnetic sensor expresses the measured magnetic field on the time axis and compares the relative magnetic field strength to diagnose whether the reinforcing bar is broken,
The magnetic sensor is characterized in that the measured magnetic field is expressed as a distance axis, and the relative strength of the magnetic field is compared to diagnose whether the reinforcing bar is broken.

The present invention positions a magnetic sensor at a certain height of a structure located above the ground surface in a structure in which reinforcing bars are embedded in a concrete electric pole, etc., and rotates the magnetic sensor in the circumferential direction to measure the magnetic field and graph it to determine the relative magnetic field strength and By comparing magnetic flux densities, it is also possible to diagnose whether or not the rebar below the surface of the earth is broken at a remote location above the surface of the earth.

Therefore, it is possible to prevent accidents by diagnosing concrete poles that are damaged due to breakage of reinforcing bars below the ground surface and replacing or reinforcing poles before the collapse accident.

In addition, the present invention can obtain a larger magnetic field signal by measuring the magnetic field after magnetizing the reinforcing bar, thereby increasing the accuracy of rebar breakage diagnosis.

In addition, the present invention has an effect of diagnosing a damaged electric pole by a relatively inexpensive and simple method with a simple configuration using a magnetic sensor and a magnet.

1 is a view showing an example of reinforcing bar breakage for the upper and lower parts of the ground surface of a concrete pole.
2 is a view showing a rebar fracture diagnosis method according to the present invention.
3 is a view showing that the position of the broken reinforcing bars in the circumferential direction of the concrete pole and how many broken rebars can be diagnosed by the rebar breakage diagnosis method according to the present invention.
4 is a graph showing the strength of the measured magnetic field on the time axis after measuring the magnetic field while rotating the magnetic sensor twice in the circumferential direction of the concrete pole shown in FIG. 3 .
5 is a view comparing magnetic flux density in the case where the reinforcing bars are connected without breaking (a) and when the reinforcing bars are broken and separated into two according to an embodiment of the present invention (b).
6 is a graph showing the results of magnetic field measurements conducted several times as an experimental rebar fracture diagnosis method.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, the method for diagnosing reinforcing bar breakage of the present invention includes the steps of positioning a magnetic sensor at a certain height above the ground surface of a concrete pole, rotating the magnetic sensor in the circumferential direction of the concrete pole, and measuring a magnetic field; and diagnosing whether the reinforcing bar is broken by using a magnetic field.

As shown in FIG. 3 , 16 reinforcing bars 3 are usually embedded in a circular shape at regular intervals inside the concrete pole 1 . The length of the reinforcing bar (3) embedded in the concrete pole (1) is approximately 2.5m (in the case of a 16m pole) from the ground surface to the floor.

In the above case, it is possible to diagnose the reinforcing bar break in a place where the contact of the magnetic sensor above the ground is possible using the magnetic field, and where the contact of the magnetic sensor at the bottom of the ground is impossible. In other words, it is possible to diagnose the breakage of reinforcing bars in the lower part of the earth's surface from a distance.

The diagnostic principle of rebar fracture is, for example, 16 pieces embedded in the concrete pole (1) while rotating the magnetic sensor (7) in the circumferential direction of the concrete pole (1) at a certain height above the ground surface of the concrete pole (1). The magnetic field generated in the reinforcing bar (3) is measured and graphed to compare the strength of the magnetic field of the reinforcing bar (3).

The magnetic sensor measures the magnetic field, the current generated in the reinforcing bar by electromagnetic induction.

The magnetic sensor 7 expresses the measured magnetic field on the time axis and compares the relative magnetic field strength along the time axis to diagnose whether the reinforcing bar is broken.

Alternatively, the magnetic sensor 7 may express the measured magnetic field as a distance axis and compare the relative magnetic field strength along the distance axis to diagnose whether the reinforcing bar is broken.

When the magnetic field strength is compared by expressing the measured magnetic field on the time axis or the distance axis, the unbroken reinforcing bar shows almost the same magnetic field strength.

In FIG. 4, the magnetic sensor is positioned at a certain height above the ground surface of the concrete pole shown in FIG. 3, and the magnetic field is measured while rotating the magnetic sensor twice in the circumferential direction of the concrete pole.

Of course, after measuring the magnetic field while rotating the magnetic sensor twice, the strength of the measured magnetic field may be expressed as a time axis.

As shown in FIG. 4 , it is confirmed that one side (a) of the concrete pole (1) has a stronger magnetic field than the other side (b) on the other side. That is, the strength of the magnetic field of one side (a) is strong and the strength of the magnetic field of the opposite side (b) is weakened repeatedly in the same pattern during two rotations.

3, the reinforcing bar (b) in the shaded portion of the dark color is the broken reinforcing bar, and the reinforcing bar (a) in the non-hatched portion is the unbroken reinforcing bar in the circumferential direction (A) of the concrete pole (1). It is possible to diagnose where the broken reinforcing bars are located and how many broken rebars there are.

A small difference occurs in the relative magnetic field strength between the broken and non-broken reinforcing bars at the bottom of the earth's surface when measured at a certain position above the surface of the concrete pole. Using this, it is possible to diagnose whether the reinforcing bars are broken in the lower part of the ground surface of the concrete pole.

Alternatively, the magnetic sensor 7 may diagnose whether the reinforcing bar is broken by comparing the magnetic flux density for each circumferential direction of the measured magnetic field.

There is a difference in magnetic flux density between rebars with and without breakage in the lower part of the earth's surface. Using this, it is diagnosed whether the reinforcing bar below the ground surface of the concrete pole is broken.

The magnetic flux density means the magnetic flux per unit area in a uniformly magnetized material, and the number of magnetic flux lines per unit area perpendicular to the direction of the magnetic flux.

Unbroken reinforcing bars have almost the same magnetic flux density, but when the reinforcing bars are broken, the magnetic flux density of the reinforcing bars changes. Therefore, there is a difference in magnetic flux density between the case where the reinforcing bar is broken and the case where the reinforcing bar is not broken.

The magnetic field is measured while rotating the magnetic sensor 7 in the circumferential direction at a certain height of the concrete pole 1 located above the ground surface. Prior to the step of measuring the magnetic field, a step of magnetizing the reinforcing bar 3 embedded in the concrete pole 1 by rotating the magnet 9 in the circumferential direction of the concrete pole 1 is performed.

For example, the reinforcing bar is magnetized by rotating the magnet in the circumferential direction in the upper 50mm and lower 50mm area based on a certain height of the concrete pole 1 located above the ground surface.

If the magnetic field is measured after the rebar is magnetized, a larger magnetic field signal can be obtained compared to the case of measuring the magnetic field without magnetization, thereby increasing the accuracy of rebar breakage diagnosis. As a magnet for magnetization, a permanent magnet may be used.

The method is, as shown in FIG. 5, after magnetizing the rebar embedded in the concrete pole by rotating the magnet along the circumferential direction of the concrete pole, rotate the magnetic sensor along the circumferential direction of the concrete pole where the magnetized rebar is located while measuring the magnetic flux density.

As shown in Fig. 5 (a), when the reinforcing bars are connected without breaking, one NS pole is formed, but as shown in Fig. 5 (b), when the reinforcing bars are broken and separated into two, NS As /NS pole, one more pole is created at the fracture part, and the difference in magnetic flux density occurs. Using this, it is possible to diagnose where the broken reinforcing bars in the circumferential direction of the concrete pole are located.

When the magnetic flux density measured by the magnetic sensor is shown in a graph, the magnetic flux density is high in the case of reinforcing bars that are not broken and connected, and the magnetic flux density is low in the reinforcing bars that are broken and separated into two pieces.

Due to the nature of the concrete pole structure, it is very difficult to diagnose the internally embedded reinforcing bars and voids with ultrasound or other non-destructive methods. is impossible with

On the other hand, in the above-described method for diagnosing rebar breakage, it is easy to diagnose damaged concrete poles due to breakage of rebars below the ground surface, so that accidents can be prevented by replacing or reinforcing the poles before the collapse accident.

The rebar breakage diagnosis device measures the magnetic field strength of the magnet 9 that magnetizes the reinforcing bar 3 embedded in the concrete pole 1, and the reinforcing bar 3 buried inside the concrete pole 1, and displays it as a graph. It includes a magnetic sensor 7 that can diagnose whether or not the reinforcing bar is broken.

The magnet 9 may use a permanent magnet.

The magnetic sensor 7 is rotated in the circumferential direction of the concrete pole 1 to measure the magnetic field of the reinforcing bar 3 embedded in the concrete pole 1, and this can be represented as a graph.

The magnetic sensor 7 includes a data logger capable of graphing the measured magnetic field.

The graph represents the magnetic field measured by the magnetic sensor 7 on the time axis to compare the relative magnetic field strength, the magnetic sensor 7 expresses the magnetic field measured on the distance axis to compare the relative magnetic field strength, and the magnetic It can be displayed by selecting one of the graphs comparing the relative magnetic flux density of the magnetic field measured by the sensor 7 .

The graph comparing the relative magnetic field strength by expressing the magnetic field measured by the magnetic sensor 7 on the time axis and the graph comparing the relative magnetic field strength by expressing the magnetic field measured by the magnetic sensor 7 on the distance axis are the magnetic field strength It is possible to determine the relatively weak part of the concrete pole (1) in the circumferential direction of the fractured reinforcing bar at the location and how many broken reinforcing bars can be diagnosed.

The graph comparing the relative magnetic flux density of the magnetic field measured by the magnetic sensor 7 can obtain a larger magnetic field signal through the process of measuring the magnetic flux density with the magnetic sensor 7 after magnetization, thereby increasing the accuracy of rebar fracture diagnosis. have.

<Experiment>

An experiment was performed to verify the method for diagnosing rebar fracture of the present invention by measuring a relative magnetic field.

The verification method is to investigate whether it can be diagnosed when the rebar installed inside the concrete pole is broken.

Concrete poles are opaque materials and there is a problem in that it is impossible to check the breakage of rebars embedded in concrete. Instead of concrete poles, instead of concrete poles, long rebars are placed inside the acrylic pipe, which is a transparent material, along the circumferential direction, and some of them are cut by oxygen cutting. did. The use of the oxygen cutting method is to prevent the occurrence of magnetization during the rebar cutting process when other methods (hacksaw, grinder, etc.) are used.

The cutting of the reinforcing bar was performed on the lower part, and the magnetization and magnetic field measurements were performed on the upper part of the reinforcing bar located at a predetermined height from the part where the rebar was cut.

6, the results of multiple experiments with the above-described method for diagnosing reinforcing bar breakage are summarized and shown as a graph. In the graph, Experiments 1 to 5 measured the magnetic field while rotating the magnetic sensor in the circumferential direction along the outer circumferential surface of the acrylic pipe. The magnetic field was measured while rotating.

At this time, in order to increase the accuracy of the experimental results, the magnetic sensor measured the magnetic field while rotating the outer peripheral surface of the acrylic pipe 5 times.

As shown in FIG. 6 , the part where the strength of the magnetic field was weak and the part where the reinforcing bar was cut coincided, and the part with the strong magnetic field matched the part where the rebar was not cut.

And, it can be seen that the strength of the magnetic field is greater in the range of the magnetic field signal (B) measured after magnetizing the reinforcing bar with a permanent magnet than the range of the signal (A) in which the magnetic field is measured without magnetization.

Through this, the magnetic sensor is positioned at a certain height of the structure located above the ground surface in a structure with reinforcing bars embedded inside such as a concrete pole, and the magnetic sensor is rotated in the circumferential direction to measure the magnetic field and graph it to determine the relative magnetic field strength and From the comparison of magnetic flux densities, it can be seen that the fracture of reinforcing bars below the surface can also be diagnosed at a remote location above the surface.

The right of the present invention is not limited to the embodiments described above, but is defined by the claims, and a person of ordinary skill in the art can make various modifications and adaptations within the scope of the claims. It is self-evident that there is

1: Concrete pole 2: Ground surface
3: reinforcing bar 4,5: reinforcing bar break
7: Magnetic sensor 9: Magnet

Claims (1)

A magnet that magnetizes the rebar buried inside the concrete pole and
In the diagnosis method by the rebar breakage diagnosis apparatus comprising; a magnetic sensor for measuring the magnetic field of the reinforcing bar,
rotating the magnet in the circumferential direction of the concrete pole and magnetizing the reinforcing bar embedded in the concrete pole;
Positioning the magnetic sensor at a certain height of the structure located above the ground surface of the concrete pole, and rotating the magnetic sensor along the circumferential direction of the concrete pole where the magnetized reinforcing bar is located, the magnetic field of the reinforcing bar embedded in the concrete pole measuring; and
Including the step of diagnosing whether the reinforcing bar is broken using the measured magnetic field,
The step of magnetizing the reinforcing bar includes magnetizing the reinforcing bar while rotating the magnet in the circumferential direction on the ground surface with respect to the reinforcing bars in the 50 mm and lower 50 mm regions above the ground surface,
The step of diagnosing whether the reinforcing bar is broken is to compare the magnetic flux densities in each circumferential direction measured at a certain position on the upper surface of the concrete pole, and determine whether or not the reinforcing bar embedded in the lower part of the ground is broken and the fracture location from the difference in the relative magnetic field strength. Diagnosis at a remote location above the surface of the earth,
The magnetic sensor expresses the measured magnetic field on the time axis and compares the relative magnetic field strength to diagnose whether the reinforcing bar is broken,
The magnetic sensor expresses the measured magnetic field as a distance axis and compares the relative magnetic field strength to diagnose whether the rebar is broken.

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