KR20070096665A - Self-vibration sensor for bridge and self-examination type bridge-bearing apparatus using it - Google Patents

Abstract

A self-examination type bridge bearing device is provided to monitor a damage condition continually and accurately and to detect an internal crack, a deformation, and a damage of a structure in real time. In a self-examination type bridge bearing device using a piezoelectric element sensor, the piezoelectric element sensor is stuck to one partial surface of a bridge with partial stress and piezoelectric-vibrated actively to receive a signal generated in a piezoelectric vibration and to detect a deformation and a damage of the bridge in real time. The pair of the piezoelectric element sensors is arranged apart about the detection area and communicated mutually by receiving and sending the signals. The self-examination type bridge bearing device comprises a port(110), an elastic rubber(120), a piston(150), and an upper plate(160). The port is fixed to the bridge, and the elastic rubber is inserted into a concave portion of the port. The piston is installed at an upper part of the elastic rubber to deliver load. The upper plate is combined with an upper surface of the piston and slid horizontally.

Description

Magnetic Vibration Sensor for Bridge and Self-diagnosis Bridge Device Using the Same {SELF-VIBRATION SENSOR FOR BRIDGE AND SELF-EXAMINATION TYPE BRIDGE-BEARING APPARATUS USING IT}

1 is an exploded perspective view showing the entire structure of a self-diagnostic type teaching apparatus according to the present invention.

Figure 2 is a schematic cross-sectional view showing the installation state of the self-diagnostic type teaching apparatus according to the present invention.

3 is a plan view showing a planar structure of the self-diagnostic type teaching apparatus according to the present invention in a partially cut state.

Figure 4 is an enlarged cross-sectional view showing a partially enlarged anchor bolt coupling structure of FIG.

<Explanation of symbols for main parts of the drawings>

100: bridge device 101: bridge

103: anchor 110: port

111: fixed plate 120: elastic rubber

130: sealing member 140: rubber sealing

150: piston 151: fluorine resin

153: guide bar 160: upper plate

161: sliding plate 171: first detection unit

173: second detection unit 175: third detection unit

The present invention relates to a bridge structure, and more particularly, to a magnetic vibration sensor for a bridge and a self-diagnostic bridge device using the same to enable continuous and precise monitoring of damage propagation to detect internal cracks, deformations and breaks in real time. will be.

In general, a structure such as a bridge is subjected to structural safety assessment after 5 years of completion, and if there is no problem, the management work is transferred to the competent supervisory authority. do. In addition, it is necessary to manage the bridges in order to prevent large accidents in advance for the bridges after a certain period of completion.

To this end, in order to check the safety of the bridge structure, a separate measuring equipment is installed at the middle point of the bridge top plate, and the test vehicle is operated to measure the load and various displacements acting on the bridge and analyze the data to measure the state of the bridge. It was.

However, the prior art as described above has a problem in that a separate measuring device must be installed for measurement, and there is a difficulty in restricting the passage of other vehicles on the bridge by operating a test vehicle loaded with such measuring equipment. Not only did it require a lot of manpower and money, but it also took a long time to measure and analyze. Furthermore, according to the prior art, there is an unreasonable need to determine the endurance life of the structure only by the data at the time of measurement because the measurement is not possible at all times.

In addition, precision safety diagnosis of the chair system is usually performed by visual inspection or by measuring a strain stress using an attached strain gauge.

However, the prior art method has a problem that the local working stress can be measured, but the critical factors such as deformation of the bridge deck and settlement of the bridge cannot be determined. In addition, only the characteristics of the structure at the time of measurement can be known, there was a problem that can not check the continuous changes (breakage) throughout the structure.

Accordingly, the present invention has been proposed to solve the conventional problems as described above, and an object of the present invention is to enable continuous and precise monitoring of damage propagation in a bridge, thereby making it difficult to visually identify internal cracks, deformations, and breakages. The present invention provides a bridge magnetic vibration sensor and a self-diagnostic bridge device using the same.

In order to achieve the above object, the magnetic vibration sensor for a bridge according to the technical idea of the present invention is attached to a part surface of a bridge where local stress is generated, and receives a signal generated during magnetic vibration while actively vibrating magnetically. It is characterized by its technical configuration to detect deformation and breakage in real time.

Here, the magnetic vibration sensor may be characterized in that it is possible to transmit and receive signals with each other while forming a pair spaced apart from each other to detect the deformation and damage.

In addition, the magnetic vibration sensor may be a PZT (piezoelectric element) sensor.

In addition, the magnetic vibration sensor may be characterized by using a mechanical surface wave (Lamb wave, Rayleigh wave) for detection.

In addition, the magnetic vibration sensor may be used for detection of changes in the wave velocity and waveform of the mechanical surface waves obtained from the emitted signal.

On the other hand, the self-diagnostic type device of the present invention includes a port fixed to a pier, an elastic rubber inserted into a recess of the port, a piston installed on an upper portion of the elastic rubber, to which a load is transmitted, and A device consisting of an upper plate that is matched to an upper surface and is slid in a horizontal direction. A magnetic vibration sensor is attached to each surface where a local stress of the teaching device is generated to detect deformation and damage in each part in real time. Forming the detector is characterized by its technical configuration.

Here, the magnetic vibration detection unit is installed on the bottom surface of the upper plate and at least one pair of magnetic vibration sensors that can transmit and receive signals inside the sliding plate that is sliding with the piston to detect the breakage of the sliding plate It may be characterized by including.

The magnetic vibration detection unit may include a second detection unit installed on at least one pair of magnetic vibration sensors capable of transmitting and receiving signals on an outer surface or an inner bottom plate of the port to detect a settlement between the port and the piers. You can do

In addition, the port is fixed to the pier by an anchor bolt, the magnetic vibration detection unit is composed of a third detection unit to detect the loosening and deformation of the bolt is installed by the magnetic vibration sensor alone at the shaft end of the anchor bolt It may be characterized by.

In addition, the magnetic vibration sensor may be a PZT (piezoelectric element) sensor.

In addition, the magnetic vibration sensor may be characterized by using a mechanical surface wave (Lamb wave, Rayleigh wave) for detection.

In addition, the magnetic vibration sensor may be characterized in that for detecting the change in the impedance value obtained from the emitted signal.

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

EXAMPLE

1 is an exploded perspective view showing the entire structure of the self-diagnostic type teaching apparatus according to the present invention, Figure 2 is an installation cross-sectional view schematically showing the installation state of the self-diagnostic type teaching apparatus according to the present invention, Figure 3 4 is a plan view showing a planar structure of the self-diagnostic type teaching apparatus according to the invention in a partially cut state, Figure 4 is an enlarged cross-sectional view showing a partially enlarged anchor bolt coupling structure of FIG.

As shown, the stapling device of the present invention includes a port 110 fixed to the pier 101 by an anchor bolt (see FIG. 4), and an elastic rubber 120 inserted into a recess of the port. The piston 150 is installed on the elastic rubber 120 and the load is transmitted, and the upper plate 160 is matched to the upper surface of the piston 150 and sliding in the horizontal direction.

At this time, a magnetic vibration sensor is attached to each surface of the local stress generating device 100 to generate a magnetic vibration sensor to detect deformation and damage in each part in real time.

Here, the magnetic vibration detector may be further divided into a first detector 171, a second detector 173, and a third detector 175 according to the detection role of each part. It is explained together with the description of each part.

The port 110 is manufactured in a cylindrical shape with an open top, and the anchor bolt 103 using a plurality of fixing plates 111 formed around the body in a state where the bottom of the cylindrical body is grounded with the upper surface of the piers 101. It is fixed to the piers 101 with).

At this time, the pier 101 is made of a concrete structure, it is constructed by injecting mortar into the closed formwork to maintain the flatness in order to distribute the vertical load uniformly from the pier device 100.

In such a closed construction, it is very important to discharge the air bubbles. If the air bubbles are not removed properly, air gaps occur between the bridge device 100 and the mortar concrete, and these initial air gaps have a continuous cyclic load. Receiving can cause a gradual settlement when received, requiring constant detection and diagnosis.

Therefore, in the present invention, as illustrated in FIGS. 1 to 3, at least one pair of magnetic vibration sensors capable of transmitting and receiving signals on the outer surface of the port 110 or the inner bottom plate of the port 110 may be installed. Forming 173, the attachment failure due to settlement between the port 110 and the pier 101 is continuously detected. Here, the second detection unit 173 is operated by a pair of the transmission-side magnetic vibration sensor 173a and the reception-side magnetic vibration sensor 173b, and each of the magnetic vibration sensors 173a and 173b performs magnetic vibration. A separate power supply is provided.

At this time, the magnetic vibration sensor (173a) (173b) is to use a PZT (piezoelectric element) sensor, the PZT sensor detects the damage of the structure by emitting a mechanical wave (Lamb wave, Rayleigh wave). Briefly, the principle is as follows.

If the phase velocity is constant with respect to the wavelength, it is a non-dispersion medium. In this case, the phase velocity and the group velocity coincide, and air is a representative example.

However, steel or concrete, which is a representative material of civil engineering structures, is a representative dispersion medium. The phase speed and the group speed are different and have unique values depending on materials and shapes. Therefore, the change in shape due to the damage of the structure or the change in stiffness due to aging causes the phase speed and the group speed to be changed, and the amount of change can be used for damage detection.

Lamb wave emitted from the PZT sensor has a long transmission distance unlike other waves (wave) has the advantage that can be diagnosed in a large area with only a small number of sensors. This has the advantage that propagation leakage of wave energy is small because wave energy penetrating into the plate is transmitted by reflection at the free upper and lower boundary of the plate.

Such a magnetic vibration sensor (PZT sensor; 173a, 173b) is to be easily attached / detached to the surface of the structure to be diagnosed damage, instantaneous adhesive or epoxy can be used for attachment, it is easy to existing bridge structure Applicable.

On the other hand, the anchor bolt 103 is a high-tensile bolt structure, pre-stress is introduced during construction. However, as time passes, the tension of the bolt gradually disappears, and eventually, the bolt is subjected to the shear force of the bolt.

In view of the bridge structure as a whole, the damage of the body of the bridge device 100 may be a functional problem, but the damage of the anchor bolt 103 causes a big safety problem.

In general, the anchor bolts of the cable bridges are regularly reintroduced and managed, but the bridge device (bridge support) 100 is mainly introduced as a device that receives vertical force. As such, there is a need for continuous detection and diagnosis thereof.

Accordingly, in the present invention, as shown in FIGS. 2 to 4, by installing the third detecting unit 175 in which the magnetic vibration sensor is installed at the shaft end of the anchor bolt 103 alone, the anchor bolt 103 is loosened and deformed. To be detected.

At this time, the third detection unit 175 is used to detect the loosening and deformation of the anchor bolt 103 by using a magnetic vibration sensor 175a consisting of a PZT (piezoelectric element) sensor alone, a brief description of the principle Is as follows.

In the case of a rod or bolt that is not in the plate shape as in the third detection unit 175, when the damage is detected, it is preferable to calculate the electrical impedance from the signal emitted from the PZT sensor and use it for detection.

Here, the impedance is a kind of transfer function obtained from the input voltage and the output current of the sensor, and the impedance value changes if there is a change in the shape, boundary condition, etc. of the target structure. That is, by detecting and comparing these change values, the loosening and deformation of the anchor bolt 103 can be detected.

Therefore, if the impedance is used, damage diagnosis is possible with the PZT sensor alone, and it is advantageous to detect local damage since it is hardly affected by external air conditions such as vibration caused by the vehicle and wind by using signals in the high frequency range. Will have

The elastic rubber 120 is inserted into the center of the port 110, the upper structure has an elastic action by the load. The elastic rubber 120 may be used natural rubber or neoprene pad. At this time, the elastic rubber 120 is expanded in the horizontal direction by the load of the upper structure, that is, the piston 150, a separate sealing member for preventing foreign matter from entering between the port 110 and the piston during the expansion process Couple 130 to the upper end.

The sealing member 130 is a kind of bushing is made in the shape of a circular band to prevent the elastic rubber 120 from entering between the gap between the port 110 and the piston 150, it may be made of brass. In addition, an additional rubber seal 140 may be further provided on the sealing member 130 to provide elastic restoring force between the piston 150 and the piston 150.

The piston 150 is inserted into the port 110 to transmit the load and impact of the upper structure to the elastic rubber 120 of the lower portion to make a linear movement in the axial direction. At this time, the upper surface of the piston 150 is attached to the fluorine resin plate 151 having a myriad of embossed grooves for accommodating lubricating oil, a guide bar 153 is formed to protrude across the center of the upper surface.

At this time, the upper plate 160 is matched to the upper surface of the piston 150 in a state capable of sliding in the horizontal direction, the upper plate 160 is bolted to the upper bridge top plate. In addition, a longitudinal groove for inserting the guide bar 153 of the piston 150 is formed at the bottom thereof, and a sliding plate 161 is formed at the left and right ends of the groove in contact with the fluorine resin plate 151. .

At this time, the sliding plate 161 is preferably made of a stainless steel sheet, the sliding performance generated between the sliding plate 161 and the fluorine resin is determined by the sliding performance of the device.

The friction coefficient of the movable support of the current road bridge design standard (2003) is 0.05 degrees, and it is desirable to maintain 50 tons of horizontal force for 1000 tons of vertical load.

In this case, the sliding plate 161 may be worn and damaged due to the loss of lubricating material of the fluorine resin plate 151. As a result, when the sliding state is poor, the operation performance of the bridge device may be deteriorated, which may cause a problem that an unexpected horizontal force is transferred to the bridge piers.

Accordingly, in the present invention, as shown in FIGS. 1 and 3, at least one magnetic vibration sensor is installed on the bottom surface of the upper plate 160 to enable signal transmission and reception inside the sliding plate 161 that slides with the piston 150. By forming the first detection unit 171 installed in the pair or more, it is to detect the damage of the sliding plate 161.

Here, the first detection unit 171 is operated by a pair of the transmission-side magnetic vibration sensor 171a and the reception-side magnetic vibration sensor 171b, and each of which is supplied with a separate power source for magnetic vibration. The magnetic vibration sensors 171a and 171b use PZT sensors that detect mechanical damage by emitting mechanical surface waves (Lamb wave, Rayleigh wave).

The preferred embodiment of the present invention has been described above. The present invention may use various changes, modifications, and equivalents. It is clear that the present invention can be applied in the same manner by appropriately modifying the above embodiments. Accordingly, the above description does not limit the scope of the invention as defined by the limitations of the following claims.

As described above, the present invention by using a magnetic vibration sensor (PZT) attached to the bridge device to serve to transfer the load of the bridge upper structure to the lower structure, it is possible to continuously monitor the damage progress, As a result, cracks, deformations and breakages inside the structure are detected in real time, thereby preventing large accidents such as bridge collapse caused by breakage of the bridge device.

In addition, the present invention is a structure that is less affected by external conditions because the signal emitted from the magnetic vibration sensor is a mechanical surface wave (Lamb wave, Rayleigh wave), there is an advantageous effect in the detection of local damage in the high frequency region.

In addition, the present invention has the effect that it is possible to detect a variety of structures from a thin plate to a thick plate because the signal emitted from the magnetic vibration sensor has the same frequency magnitude.

In addition, the present invention because the magnetic vibration sensor vibrates by itself, it is possible to clearly know the input vibration characteristics and to monitor the cracks and damage inside the structure in real time without external assistance.

Claims (12)

A magnetic vibration sensor for bridges that is attached to a part of the surface where local stresses are generated and actively detects vibrations and receives signals generated during magnetic vibrations in order to detect deformation and breakage of the bridges in real time. The method of claim 1, The magnetic vibration sensor, the magnetic vibration sensor for the bridge, characterized in that the mutual signal transmission and reception while forming a pair spaced apart between the area to detect the deformation and damage. The method according to claim 1 or 2, The magnetic vibration sensor is a magnetic vibration sensor for a bridge, characterized in that the PZT (piezoelectric element) sensor. The method according to claim 1 or 2, The magnetic vibration sensor is a magnetic vibration sensor for a bridge, characterized in that for detecting the mechanical surface wave. The method of claim 2, The magnetic vibration sensor is a magnetic vibration sensor for a bridge, characterized in that for detecting the change in the impedance value obtained from the emitted signal. A port fixed to the pier, an elastic rubber inserted into the recess of the port, a piston installed on the upper portion of the elastic rubber, to which a load is transmitted, and an upper plate mated to the upper surface of the piston and sliding in a horizontal direction As a device consisting of, Self-diagnostic type teaching apparatus, characterized in that the magnetic vibration sensor is attached to each surface where the local stress of the teaching device is generated so that deformation and breakage in each part is detected in real time. The method of claim 6, The magnetic vibration detection unit includes a first detection unit installed on the bottom surface of the upper plate to install at least one pair of magnetic vibration sensors capable of transmitting and receiving signals inside the sliding plate that slides with the piston to detect breakage of the sliding plate. Self-diagnostic type teaching apparatus, characterized in that. The method of claim 6, The magnetic vibration detection unit may include a second detection unit installed on at least one pair of magnetic vibration sensors capable of transmitting and receiving signals on an outer surface or an inner bottom plate of the port to detect a settlement between the port and the piers. Self-diagnostic chair. The method of claim 6, The port is fixed to the pier by anchor bolts, The magnetic vibration detection unit is a self-diagnostic type device characterized in that the magnetic vibration sensor is installed alone at the shaft end of the anchor bolt to detect the loosening and deformation of the bolt. The method according to any one of claims 6 to 9, The magnetic vibration sensor is a self-diagnostic type device, characterized in that the PZT (piezoelectric element) sensor. The method of claim 10, The magnetic vibration sensor is a self-diagnostic type device, characterized in that for detecting the mechanical surface wave. The method of claim 11, The magnetic vibration sensor is a self-diagnostic type device, characterized in that for detecting the change in the impedance value obtained from the emitted signal.

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