JP5868653B2 - Interface inspection method and interface inspection apparatus for composite structure - Google Patents

Description

  The present invention relates to an interface inspection method and an interface inspection apparatus for a composite structure, and more particularly to an interface inspection method for confirming a filling state of concrete and an interface inspection apparatus for performing the interface inspection method.

In general, as a method for constructing a composite structure such as a highway bridge, a construction method is known in which a steel girder upper structure and a pier lower structure are rigidly connected to form an upper and lower integrated structure. Such a composite structure causes a decrease in strength when there is a void in the concrete due to corrosion of the reinforcing member provided inside the concrete due to long-term use or insufficient filling of the concrete during construction.
It is known that the corrosion inspection of such a composite structure is performed by a nondestructive inspection using an ultrasonic probe (see Patent Document 1).

JP 2003-14704 A

  By the way, as shown in FIG. 11, the rigid connection part 103 which rigidly connects the steel girder upper part 101 and the pier lower part 102 fits the thick steel plate 104 to the rigid connection part upper part, and is placed by the thick steel plate 104 It is formed by placing concrete from the hole 105. The thick steel plate 104 is formed with air holes 108 for extracting air in the concrete, and the air contained in the concrete rises and escapes from the air holes 108. There are also cases where two-stage placement in which mortar is press-fitted after concrete placement is performed.

  However, the air in the concrete does not escape from the air holes 108 and a gap 109 may be formed between the thick steel plate 104 and the concrete interface 106. Such a gap 109 may be generated between the reinforcing member 110 such as a rib and the concrete interface 106. If a large number of gaps 109 are formed, the strength of the rigid joint 103 is affected, which is not preferable. However, in order to confirm whether or not a void is formed in the concrete interface 106, the concrete filling state in the pipe installed in the air hole 108 at the time of placing must be visually observed. It was difficult to confirm the presence or absence of the entire void.

  In this regard, the technique disclosed in Patent Document 1 detects corrosion between the concrete formed on the top of the steel sheet and the steel sheet, and this technique is used for the inspection of the rigid joint. Even if it is intended to be applied, it is very difficult to detect a void generated at the concrete interface placed under the thick steel plate 104.

  The present invention has been made to solve the above-described problems, and the object of the present invention is to efficiently form voids formed between a steel plate and a concrete interface of a composite structure using an ultrasonic flaw detection method. It is an object to provide an interface inspection method and an interface inspection apparatus for a composite structure that can be inspected.

In order to achieve the above object, an interface inspection method for a composite structure according to claim 1 is a rigid connection part that rigidly connects a steel plate and a pier lower part provided between a steel girder upper part and a pier lower part of a bridge. Reflected wave intensity for transmitting the ultrasonic wave from the ultrasonic probe arranged on the thick steel plate to the interface of the placed concrete, receiving the reflected wave from the bottom surface of the thick steel plate, and measuring its strength In the reflected wave intensity measurement step, the measurement step includes a filling state determination step that compares the measured reflected wave intensity with a preset threshold value and determines whether or not the concrete filling state is sufficient. The intensity of the reflected wave at the Nth time (N is 1 or more) from the bottom surface of the thick steel plate is measured, and the number of reflections N is selected according to the thickness of the thick steel plate .

Interface inspection method of a composite structure of claim 2, in claim 1, wherein the pre Kihan morphism number is either one to three times.

An interface inspection apparatus for a composite structure according to claim 3 is disposed on a thick steel plate provided above a beam of a bridge, transmits an ultrasonic wave and receives an reflected wave thereof, and the thickness Sending ultrasonic waves from the ultrasonic probe to the concrete interface placed at the rigid joint that rigidly connects the steel plate and the lower part of the pier, receiving the reflected wave from the bottom surface of the thick steel plate, A reflected wave intensity measuring means for measuring the intensity, and a filling state determining means for comparing the intensity of the measured reflected wave with a preset threshold and determining whether or not the filling state of the concrete is sufficient, the reflected wave strength measurement hand stage, the intensity of the reflected wave of the N-th from the steel plate bottom surface (N is 1 or more) was measured, that the number of reflections N is selected according to the thickness of said steel plate Features.

Interface inspection apparatus of the composite structure of claim 4, in claim 3, characterized in that before Kihan morphism number is either one to three times.

  The interface inspection apparatus for a composite structure according to claim 5 is characterized in that, in claim 3 or 4, the ultrasonic wave is set at a frequency of 50 kHz to 1 MHz.

  According to a sixth aspect of the present invention, there is provided the composite structure interface inspection apparatus according to any one of the third to fifth aspects, further comprising moving means for moving the ultrasonic probe by a preset distance.

  An interface inspection apparatus for a composite structure according to a seventh aspect of the present invention is the interface for inspecting a composite structure according to any one of the third to sixth aspects, comprising: a notifying means that issues an alarm when the filling state determining means determines that the concrete filling state is insufficient. It is characterized by providing.

  An interface inspection apparatus for a composite structure according to claim 8 is the ultrasonic probe according to any one of claims 3 to 7, wherein the filling state determining means determines that the concrete filling state is insufficient. It is characterized by comprising marking means for marking on a thick steel plate on which is arranged.

According to the interface inspection method for a composite structure according to claim 1, ultrasonic waves are incident from the upper part of the thick steel plate of the rigid joint , and the intensity of the reflected wave at the Nth time (N is 1 or more) from the bottom surface of the thick steel plate is measured. Based on the strength, the filling state of the concrete interface under the thick steel plate is determined. Here, the number N of reflections is selected according to the thickness of the thick steel plate.
According to the interface inspection apparatus for a composite structure of claim 3, the ultrasonic wave is transmitted from the ultrasonic probe disposed on the thick steel plate of the rigid connection portion, and the Nth time (N Measure the intensity of the reflected wave of 1 or more), and determine the filling state of the concrete interface under the thick steel plate based on the intensity. Here, the number N of reflections is selected according to the thickness of the thick steel plate.

Thereby, the filling state of the concrete interface can be efficiently inspected without visual observation.
Moreover, the quality of construction can be easily grasped by determining the filling state of the concrete interface.

It is a schematic block diagram of the interface inspection apparatus of the composite structure which concerns on this invention. It is a flowchart which shows the interface inspection method which concerns on this invention. (A) is a figure showing the attenuation | damping state of an ultrasonic wave when the space | gap is not formed in a concrete interface, (B) is a figure showing the attenuation | damping state of an ultrasonic wave when the space | gap is formed in a concrete interface. is there. It is a graph showing the change of the echo height of the ultrasonic wave with respect to the size of the simulated air gap. (A) is a graph showing the result of the interface inspection of the subject with a frequency of 100 kHz and a transducer diameter of 38 mm, and (B) shows the result of the interface inspection of the subject with a frequency of 100 kHz and a transducer diameter of 90 mm. Graph, (C) is a graph showing the result of the interface inspection of the subject at a frequency of 250 kHz and a transducer diameter of 38 mm, and (D) is the result of the interface inspection of the subject at a frequency of 500 kHz and a transducer diameter of 40 mm. It is a graph showing. It is a graph showing the result of having performed the interface test | inspection of the subject at the frequency of 1 MHz. It is a graph showing the result of having performed the interface test | inspection of the test object with the frequency of 500 kHz. It is a schematic block diagram of the interface inspection apparatus which concerns on the modification of embodiment. It is a schematic block diagram of the interface inspection apparatus which concerns on the other modification of embodiment. It is a schematic block diagram of the interface inspection apparatus which concerns on the further another modification of embodiment. It is sectional drawing of the rigid connection part as an example of a composite structure.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a composite structure interface inspection apparatus according to the present invention. The interface inspection apparatus 1 is an apparatus for inspecting the filling state of the interface of concrete 4 placed in a rigid connection portion 2 that rigidly connects a thick steel plate 3 provided at the upper part of a bridge and a lower part of a bridge pier, for example. .

  As shown in FIG. 1, an interface inspection apparatus 1 includes an ultrasonic probe 7 connected to a pulsar 5 and a receiver 6, and an analog / digital converter (hereinafter referred to as A / D conversion) connected to the pulsar 5 and the receiver 6. 8) and an arithmetic unit 9.

  The pulser 5 applies an electrical pulse based on a command signal from the arithmetic unit 9 to the ultrasonic probe 7, and the receiver 6 receives the reflected wave from the bottom surface of the thick steel plate 2 received by the ultrasonic probe 7. It converts to an electrical signal. The electrical signal converted by the receiver 6 is input to the arithmetic device 9 via the A / D converter 8 and can be monitored by the display device 10.

  The calculation device 9 includes a calculation unit 11 and a memory 12 including a ROM, a RAM, and the like. In the calculation unit 11, the reflected wave received by the ultrasonic probe 7 is analyzed, and the analysis result is stored in the memory 12.

  An interface inspection method for inspecting the filling state of the concrete interface of the rigid joint 2, that is, the interface 4 a of the concrete 4 placed under the thick steel plate 3, using the interface inspection apparatus 1 configured as described above will be described. . FIG. 2 shows a flowchart of the interface inspection method for the interface 4a of the concrete 4, and will be described below based on the flowchart. In addition, the process after step S3 mentioned below is performed by the calculating part 11. FIG.

  In step S1, the ultrasonic probe 7 is disposed on the thick steel plate 3 having the same specifications as the rigid connection portion of the subject, the echo height from the bottom surface 3a of the thick steel plate is measured, and the thickness of the thick steel plate 3 is measured. Accordingly, the flaw detection sensitivity used for the ultrasonic flaw detection of the subject is set in the arithmetic unit 9. The thickness of the thick steel plate 3 of the rigid connection portion 2 to be inspected in the present embodiment is selected from the range of 25 to 100 mm.

  In step S2, the ultrasonic probe 7 is disposed on the thick steel plate 3 of the subject, ultrasonic waves are transmitted toward the thick steel plate bottom surface 3a, and the echo height of the Nth reflected wave from the thick steel plate bottom surface 3a. Measure the thickness. Here, the number N of reflections is selected according to the thickness of the thick steel plate 3 and is usually selected from the first to third ranges in consideration of the influence of noise due to sensitivity adjustment of the interface inspection apparatus 1.

  Here, the change of the reflected wave of the ultrasonic wave in the case where there is no void in the concrete interface 4a and the case where it exists will be described. FIG. 3 (A) shows an ultrasonic attenuation state when ultrasonic flaw detection is performed on a sound part in which no gap is formed in the concrete interface 4a, and FIG. 3 (B) shows a gap in the concrete interface 4a. An ultrasonic attenuation state when ultrasonic flaw detection is performed when CL is formed is shown.

  As shown in FIG. 3A, when no gap is formed in the concrete interface 4a corresponding to the position where the ultrasonic wave incident from the ultrasonic probe 7 is reflected by the thick steel plate bottom surface 3a, the ultrasonic probe is used. When the ultrasonic wave incident on the thick steel plate 3 from 7 is reflected by the bottom surface 3 a of the thick steel plate, a part of the ultrasonic wave propagates in the concrete 4. For this reason, every time an ultrasonic wave is reflected on the thick steel plate bottom surface 3a, the ultrasonic wave is attenuated. Here, the echo height when transmitting ultrasonic waves from the ultrasonic probe 7 is E0, the echo height of the first reflected wave B1 from the thick steel plate bottom surface 3a is E1, and the echo of the reflected wave B2 of the first time. When the height is E2, and the echo height of the third reflected wave B3 is E3, the relationship between the echo heights is E0> E1> E2> E3.

  On the other hand, as shown in FIG. 3B, when the gap CL is formed in the concrete interface 4a corresponding to the position where the ultrasonic wave incident from the ultrasonic probe 7 is reflected by the bottom surface 3a of the thick steel plate, the ultrasonic wave The ultrasonic wave incident from the probe 7 is reflected without being attenuated when reflected by the thick steel plate bottom surface 3a. That is, the echo heights of the first to third reflected waves B1 to B3 are approximately equal to the echo height of the ultrasonic waves during ultrasonic transmission.

  Therefore, by measuring the echo height of the reflected wave from the thick steel plate bottom surface 3a, it is possible to identify whether or not a void is formed in the concrete interface 4a. Note that which one of the first to third reflected waves B <b> 1 to B <b> 3 is measured depends on the thickness D of the thick steel plate 3. For example, if the thickness of the thick steel plate 3 is about 30 mm, the sound portion and the gap CL can be identified by measuring the echo height of the reflected wave B1. As will be described later, if the thickness of the thick steel plate 3 is 75 mm, the sound part and the gap CL can be identified by measuring the echo height of the reflected wave B3.

  On the other hand, the reflected waves after the fourth time can be received by the ultrasonic probe 7, but the electric signal is weak and cannot be distinguished from noise. Further, if the flaw detection sensitivity is increased in order to accurately receive the reflected waves after the fourth time, there is a problem that noise increases and the S / N ratio is deteriorated. For these reasons, it is not preferable to use the fourth and subsequent reflected waves.

  Next, a change in the echo height of the ultrasonic wave on the bottom surface 3a of the thick steel plate with respect to the size of the gap CL formed in the concrete interface 4a will be described with reference to FIG. FIG. 4 is a graph showing changes in ultrasonic echo height with respect to the size (diameter) of each simulated gap. In FIG. 4, the D = 75 mm thick steel plate 3 is used, and the ultrasonic intensity incident on the thick steel plate 3 from the ultrasonic probe 7 having a frequency of 250 kHz and a transducer diameter of 38 mm is used as a reference (0 dB). 3 is a graph showing the amount of echo height drop measured from a subject with respect to the ultrasonic intensity. Note that the specimen used for measurement to represent the graph of FIG. 4 is one in which simulated voids of various sizes are formed on the back surface of the thick steel plate 3 of 75 mm and concrete is cast.

  As shown in FIG. 4, when the gap is not formed, that is, the difference d1 between the echo height of the reflected wave B1 at the healthy portion and the echo height of the reflected wave B1 when the simulated gap diameter is 100 mm is about 3 dB. There was no significant difference. On the other hand, the difference d3 between the echo height of the reflected wave B3 at the healthy part and the echo height of the reflected wave B3 when the simulated gap diameter is 100 mm was about 10 dB. Therefore, it was found that with a 75 mm thick steel plate, by measuring the echo height of the reflected wave B3, a significant difference can be obtained in the echo height between the sound part and the case where the gap is formed.

  In subsequent step S3, it is determined whether or not the echo height measured in step S2 is less than a threshold value previously set in the memory 11 or the like. As shown in FIG. 4, the size of the gap and the echo height from the thick steel plate bottom surface 3 a have a correlation, and the size of the gap CL is estimated by measuring the echo height in the Nth reflected wave. be able to. Therefore, the determination is performed using a threshold value set in advance in the memory 12 or the like. Specifically, an echo height that the filling state of the concrete interface 4a in the Nth reflected wave is insufficient is set in advance as a threshold value, and determination is performed using the threshold value. If the determination result is true (Yes), the process proceeds to step S4. If the determination result is false (No), the process proceeds to step S5.

  In step S4, since the measured echo height is less than the threshold value, it is determined that the void existing in the concrete interface 4a is within the allowable range, and the filling state of the concrete interface 4a is sufficient, and this flowchart is ended. To do.

On the other hand, in step S5, since the measured echo height is equal to or greater than the threshold value, the void existing in the concrete interface 4a exceeds the allowable range, and it is determined that the filling state of the concrete interface 4a is insufficiently filled. This flowchart is terminated.
The interface inspection method from steps S1 to S5 described above is performed at a plurality of locations on the thick steel plate 3, and the filling state of the concrete interface 4a in the entire rigid joint 2 is inspected.

  By the way, in the rigid connection part 2 which is a composite structure used in the present embodiment, a reinforcing bar is embedded in the concrete 4, and the ultrasonic wave propagated in the concrete from the thick steel plate back surface 3a is reflected on the reinforcing bar and reflected. There is a concern that the echo height of the ultrasonic wave that has been affected affects the echo height of the reflected wave from the bottom surface 3a of the thick steel plate. Therefore, the influence of the reflected wave from the reinforcing bar in the concrete 4 will be described below.

It is considered that the reflected wave from the reinforcing bar having a depth of about 30 mm from the concrete interface 4a has a great influence on the Nth reflected wave from the thick steel plate bottom surface 3a. Therefore, if the echo height from the reinforcing bar (φ12 mm) in the concrete 4 at a depth of 30 mm from the concrete interface 4a is Bc and the echo height of the ultrasonic wave incident on the thick steel plate 3 is U, the echo from the reinforcing bar Height Bc is
Bc = 0.027U (1)
It is represented by

On the other hand, among the first to third reflected waves from the thick steel plate bottom surface 3a, the third echo height Bn where the echo height is the smallest is:
Bn = 0.22U (2)
It is represented by

  Thus, from equation (1), the echo height Bc from the reinforcing bar embedded in the concrete 4 is about 0.1 times the third echo height Bn from the bottom surface 3a of the thick steel plate, and the present invention It can be seen that there is almost no influence on the echo height of the Nth time measured with the above, and that the size is negligible.

  Next, the influence of a reflected wave from any reflector in the concrete 4 that appears at a position substantially equal to the third reflected wave B3 from the thick steel plate bottom surface 3a will be described below. For example, if a reinforcing bar (φ12 mm) exists in the concrete 4 having a depth of about 108 mm from the concrete interface 4a, the ultrasonic wave incident from the ultrasonic probe 7 propagates in the concrete 4 and is reflected by the reinforcing bar, and the bottom surface of the thick steel plate A reflected wave from the reinforcing bar appears at a position substantially equal to the position where the third reflected wave B3 from 3a appears.

Here, if the echo height of the reflected wave from the reinforcing bar at a depth of about 108 mm is Bd,
Bd = 0.007U (3)
It is represented by

Compared with the echo height Bn in the third reflected wave B3 shown in Equation (2), the echo height Bd was about 0.003 times the third echo height Bn from the steel plate bottom surface 3a. . Therefore, even when there is a reflected wave from the reinforcing bar in the concrete 4 that appears at a position substantially equal to the third reflected wave B3, it can be seen that the magnitude is sufficiently negligible.
Thus, it can be seen that the reflected wave from the reflector such as a reinforcing bar embedded in the concrete can be sufficiently ignored.

  Next, in order to investigate the frequency suitable for the interface inspection method described above for the third reflected wave B3 from the steel plate bottom surface 3a, the interface inspection of the concrete 4 was performed using a specimen provided with a simulated gap. The resulting graphs are shown in FIGS. FIGS. 5A to 5D are graphs showing the results of the interface inspection of the concrete interface 4a by changing the frequency of the ultrasonic probe 7 and the transducer diameter. FIG. 6 is a graph obtained by measuring the echo height of a subject having a simulated gap formed at a frequency of 1 MHz, and FIG. 7 is a graph obtained by measuring the echo height of the subject formed by a simulated gap having a frequency of 500 kHz. 6 and 7, the ultrasonic probe 7 having a transducer diameter of 25.4 mm was used. Moreover, the thickness D of the thick steel plate 3 used in FIGS. 5 to 7 is 75 mm.

  The specimen placed in the upward direction of the steel plate of CASE 1 described in FIGS. 5 to 7 represents a specimen produced by placing concrete under the thick steel plate 3 as shown in FIG. In addition, the CASE 2 specimen placed in a steel plate downward direction represents a specimen in which the thick steel plate 3 is placed below and concrete is placed thereon so that a void other than the simulated void is not formed in the concrete interface 4a. ing. In this manner, the interface inspection of the concrete interface 4a was performed on the CASE 1 that is the specimen manufactured by the same method as the rigid connection part 2 that is actually manufactured and the CASE 2 that is the ideal specimen.

  As shown in FIG. 5A, at a frequency of 100 kHz, the difference in echo height between the healthy part where the gap CL is not formed and the simulated gap having a diameter of 50 mm is about 5 dB for both CASE1 and CASE2. As shown in FIG. 5B, when the transducer diameter of the ultrasonic probe 7 is 90 mm at the same frequency, the difference in echo height between the healthy portion and the simulated gap having a diameter of 50 mm is about 6 dB. When the interface inspection is performed at a frequency of 250 kHz in FIG. 5C and at a frequency of 500 kHz in FIG. 5D, the difference between the healthy portion and the simulated gap having a diameter of 50 mm increases as the frequency is increased. A difference in echo height is clearly seen in both CASE2.

  As shown in the graph of FIG. 6, when the transducer diameter of the ultrasound probe 7 is 25.4 mm and the frequency is 1 MHz, the echo height between the healthy part and the simulated gap having a diameter of 50 mm in the CASE 1 subject is obtained. The difference was about 7.5 dB. On the other hand, as shown in the graph of FIG. 7, when the frequency was set to 500 kHz, the difference in echo height between the healthy part and the simulated gap having a diameter of 50 mm was about 7 dB.

  From the above, it is preferable that the frequency used in the interface inspection method and the interface inspection apparatus 1 of the present embodiment is selected from the range of 50 kHz to 1 MHz according to the thickness D of the thick steel plate 3. Further, the transducer diameter of the ultrasonic probe 7 is appropriately selected according to the thickness D of the thick steel plate 3. Furthermore, as the ultrasonic probe 7, a convergent probe having an ultrasonic beam capable of detecting the unfilled size of the target concrete interface 4a may be used.

As described above, in this embodiment, the ultrasonic probe 7 is disposed on the thick steel plate 3 constituting the rigid coupling portion 2, and the ultrasonic wave is transmitted to transmit the Nth reflected wave from the thick steel plate bottom surface 3a. The echo height is measured, and the filling state of the concrete 4 is determined based on the measured echo height.
Thereby, the filling state of the concrete interface 4a can be inspected efficiently without relying on visual observation.
Moreover, it is possible to easily grasp whether the construction is good or bad by grasping the filling state of the concrete interface 4a.

<Modified example of interface inspection device>
A modification of the above embodiment will be described below. This modification is different in that the interface inspection apparatus 1 is provided with a moving means for moving on the thick steel plate 3, and the other configurations are the same, so that the description thereof is omitted.

  FIG. 8 is a schematic configuration diagram showing an outline of a modified example of the interface inspection apparatus 1. The interface inspection apparatus 1 a includes a moving unit 20 that can move on the thick steel plate 3 and a control unit 21 a that controls the moving unit 20. The moving means 20 may be a wheel, for example. Although not shown, the control unit 21a may be provided in the arithmetic device 9.

  The control unit 21a controls the moving unit 20 so as to move the interface inspection apparatus 1a to the next measurement point on the thick steel plate 3 at intervals set in advance in the memory 11 or the like. Further, the control unit 21a may control the ultrasonic probe 7 to move up and down so that the ultrasonic probe 7 is brought into contact with or separated from the surface of the thick steel plate 3. For example, the control unit 21a controls the ultrasonic probe 7 to move away from the surface of the thick steel plate 3 before moving the interface inspection apparatus 1a. You may make it control so that it may contact | abut on the steel plate 3 surface.

  Thus, since the control part 21a controls the moving means 20 and the interface inspection apparatus 1a is automatically moved to a predetermined measurement point, the interface inspection of the concrete interface 4a can be performed more easily.

<Other variations of interface inspection device>
Another modification of the above modification will be described below. In this modified example, the interface inspection apparatus 1a is further provided with a notifying unit, and the other configurations are common, and thus description thereof is omitted.

  FIG. 9 is a schematic configuration diagram illustrating another modification of the interface inspection apparatus 1. The interface inspection apparatus 1 b includes a control unit 21 b and a speaker (notification unit) 22. The control unit 21b controls the movement of the moving means 20 as in the above-described modification, and controls the speaker 22 so as to notify an inspection person inspecting with the interface inspection apparatus 1b.

  Specifically, in step S3, the echo height of the Nth reflected wave from the thick steel plate bottom surface 3a measured by the ultrasonic probe 7 is equal to or greater than a threshold value, that is, the insufficient filling in step S5 and the calculation unit 11 described above. When the determination is made, a signal notifying that filling is insufficient is notified from the calculation unit 11 to the control unit 21b. When the signal is notified, the control unit 21b controls the speaker 22 so as to notify the surrounding person in charge of the inspection to be notified from the speaker 22.

  As described above, when the calculation unit 11 determines that the echo height of the N-th reflected wave from the bottom surface 3a of the thick steel plate is equal to or greater than the threshold value, the surrounding inspection personnel are notified based on the signal from the calculation unit 11. The speaker 22 is controlled by the control unit 21b. Thereby, when the clearance CL more than an allowable range exists in the concrete interface 4a in the measurement point of the thick steel plate 3, the presence can be easily grasped by the surrounding inspectors.

<Still another modification of interface inspection apparatus>
Another modification of the above modification will be described below. In this modified example, the interface inspection apparatus 1a is further provided with a marking unit, and the other configurations are common, and thus the description thereof is omitted.

  FIG. 10 is a schematic configuration diagram showing still another modified example of the interface inspection apparatus 1. The interface inspection apparatus 1 c includes a control unit 21 c and a marking unit 23. The control unit 21c controls the movement of the moving unit 20 as in the above modification, and controls the marking plate 23 to mark the surface of the thick steel plate 3.

  Specifically, in step S3, the calculation unit 11 determines that the echo height of the N-th reflected wave from the thick steel plate bottom surface 3a measured by the ultrasonic probe 7 is equal to or greater than a threshold value, that is, insufficient filling in step S5. Then, a signal that the filling is insufficient is notified from the calculation unit 11 to the control unit 21b. When the signal is notified to the control unit 21c, the control unit 21c controls the marking means 23 so as to mark the surface of the thick steel plate 3 corresponding to the concrete interface 4a in which insufficient filling is detected.

  As described above, when the calculation unit 11 determines that the echo height of the Nth reflected wave from the thick steel plate bottom surface 3 a is equal to or greater than the threshold value, the surface of the thick steel plate 3 is marked based on the signal from the calculation unit 11. The control unit 21 c controls the marking unit 23. Thereby, the location where the clearance CL more than an allowable range is formed in the concrete interface 4a can be grasped easily. In addition, after the concrete is further placed on the rigid portion 2, the measurement location can be easily grasped when re-inspecting the filling state of the concrete interface 4a.

Although the description of the embodiment is finished as described above, the present invention is not limited to the above-described embodiment.
For example, the interface inspection apparatuses 1a to 1c according to the above modifications may be used in combination, and the notification means according to the other modifications and the marking means according to the other modifications may be applied to the embodiment. Also good.

In the above embodiment, the threshold value is set in advance in the memory 11 or the like. However, by obtaining a correlation between the size of the gap CL and the echo height in advance in the subject or the like, and setting the threshold value from the relationship, the concrete is set. The interface state of the interface 4a can be determined more appropriately.
Moreover, in the said other modification, although the speaker 22 was provided in the interface inspection apparatus 1b as an alerting | reporting means, you may make it provide the light emission part (for example, warning lamp etc.) using light-emitting bodies, such as a light bulb and LED. .

DESCRIPTION OF SYMBOLS 1, 1a, 1b, 1c Interface inspection apparatus 2 Rigid connection part 3 Thick steel plate 3a Thick steel plate bottom face 4 Concrete 4a Concrete interface 7 Ultrasonic probe 9 Arithmetic unit 11 Arithmetic unit

Claims (8)

An ultrasonic probe placed on the thick steel plate against the interface between the thick steel plate provided between the upper part of the steel girder of the bridge and the lower part of the pier and the concrete interface placed in the rigid connection part that rigidly connects the lower part of the pier. A reflected wave intensity measuring step of transmitting an ultrasonic wave from the child, receiving a reflected wave from the bottom surface of the thick steel plate, and measuring its intensity;
Comparing the measured reflected wave intensity with a preset threshold value, and determining whether or not the concrete filling state is sufficient,
In the reflected wave intensity measuring step, the intensity of the Nth reflected wave from the bottom surface of the thick steel plate (N is 1 or more) is measured, and the number of reflections N is selected according to the thickness of the thick steel plate. An interface inspection method for composite structures. Interface inspection method of a composite structure according to claim 1, wherein the pre Kihan morphism number is either one to three times. An ultrasonic probe that is arranged on a thick steel plate provided on the upper part of the bridge beam and transmits ultrasonic waves and receives the reflected waves;
Sending ultrasonic waves from the ultrasonic probe to the concrete interface placed in the rigid joint that rigidly connects the thick steel plate and the lower part of the pier, and receiving reflected waves from the bottom surface of the thick steel plate Reflected wave intensity measuring means for measuring the intensity;
Comparing the measured intensity of the reflected wave with a preset threshold value, and comprising a filling state determination means for determining whether the concrete filling state is sufficient,
The reflected wave strength measurement hand stage, the intensity of the reflected wave of the N-th from the steel plate bottom surface (N is 1 or more) was measured, that the number of reflections N is selected according to the thickness of said steel plate A complex structure interface inspection device. Interface inspection apparatus of a composite structure according to claim 3, characterized in that the number of times before Kihan morphism is either one to three times.   5. The interface inspection apparatus for a composite structure according to claim 3, wherein the ultrasonic wave is set at a frequency of 50 kHz to 1 MHz.   6. The composite structure interface inspection apparatus according to claim 3, further comprising moving means for moving the ultrasonic probe by a preset distance.   The composite structure according to any one of claims 3 to 6, further comprising notification means for notifying based on the determination when the filling state determination means determines that the concrete filling state is insufficient. Interface inspection equipment.   A marking means for marking on a thick steel plate on which the ultrasonic probe is arranged when the concrete filling state is judged to be insufficient by the filling state judging means. The interface inspection apparatus for a composite structure according to any one of 7.

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