JP6804730B2 - Inspection method for steel plate concrete structure, manufacturing method for steel plate concrete structure, and inspection jig - Google Patents

Description

The techniques disclosed herein relate to methods of inspecting structures of steel plate concrete structures.

As a structure of a building or a civil engineering structure, a steel plate concrete structure (hereinafter referred to as "SC structure") in which a steel plate and concrete are combined is known. In the SC structure, concrete is filled between two steel plates, and the studs welded inside each steel plate are restrained by the concrete, which prevents local buckling of the steel plates and fully demonstrates the resistance of the steel plates. can do.

In the SC structure, a skin gap may be formed between the steel plate and the concrete due to the drying shrinkage of the filled concrete. In addition, voids may be formed between the steel plate and concrete due to insufficient filling of concrete. If these skin gaps and voids (hereinafter collectively referred to as "voids") are small, there is often no problem, but if large voids are formed, the strength required for design cannot be maintained. Therefore, it may be a problem. Therefore, it is necessary to inspect the size of the void formed between the steel plate and the concrete.

Conventionally, the transmission point and the reception point are set at different positions on the same steel plate, and the time from the time until the vibration emitted from the transmission point reaches the reception point through the concrete is between the transmission point and the reception point. A technique for estimating the size of the voids formed in the concrete is known (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2011-133415

If the transmitting point and the receiving point are set at different positions as in the above-mentioned prior art, there is a problem that the inspection accuracy is lowered due to the fluctuation of the distance between the transmitting point and the receiving point, for example.

This specification discloses a technique capable of solving at least a part of the above-mentioned problems.

(1) The inspection method disclosed in the present specification is an inspection method for a structure having a steel plate concrete structure in which concrete is filled between the first steel plate and the second steel plate facing the first steel plate. A step of forming a through hole in the first steel plate and a columnar first waveguide member are arranged so that one end of the first waveguide member is inserted into the through hole and comes into contact with the concrete. The columnar second waveguide member does not come into contact with the first waveguide member, and one end of the second waveguide member is inserted into the through hole to come into contact with the concrete. After the step of arranging the end portion of the first waveguide member on the one end side and the end portion of the second waveguide member on the one end side so as to surround the other, and the step of arranging the first waveguide member, the above-mentioned step. After the step of striking the striking surface provided on the first waveguide member and having an outer dimension larger than the outer dimension of the one end of the first waveguide member, and the step of arranging the striking surface. , The step of measuring the vibration of the second waveguide member and the elapsed time from the time when the striking surface is hit to the measurement of the vibration having an amplitude equal to or larger than the reference amplitude in the second waveguide member. It comprises a step to identify. According to this inspection method, a through hole is formed in the first steel plate, and the first waveguide member and the second waveguide member are brought into contact with concrete through a common through hole. Therefore, the distance between the first waveguide member and the second waveguide member varies as compared with the case where the first waveguide member and the second waveguide member are brought into contact with the concrete through separate through holes. By suppressing it, it is possible to suppress a decrease in inspection accuracy.

(2) In the above inspection method, the measuring step is a step of measuring the vibration of a specific frequency corresponding to the length from one end of the first waveguide member in the axial direction to the striking surface. May be good. According to this inspection method, by measuring the vibration of the second waveguide member having a specific frequency, it is possible to measure the vibration of the second waveguide member caused by the impact on the impact surface.

(3) In the above inspection method, the first waveguide member is opened at one end of the first waveguide member, extends in the axial direction of the first waveguide member, and is said to be the first waveguide member. A vacancy extending between one end and the striking surface, and a communication hole located on the outer periphery of the vacancy of the first waveguide member and communicating the vacancy with the outside of the first waveguide member. , And the second waveguide member includes a main body portion arranged inside the hole and a protruding portion protruding from the main body portion to the outside of the first waveguide member through the communication hole. The step of arranging the second waveguide member is a step of bringing the second waveguide member into contact with the concrete by pressing the protruding portion toward the concrete side to arrange the second waveguide member. May be. According to this inspection method, since the second waveguide member has a protruding portion, the second waveguide member can be surely brought into contact with the concrete.

(4) In the above inspection method, further, after the measurement step, a step of removing the first waveguide member and the second waveguide member from the through hole and filling the through hole with a filling member is performed. It may be provided. According to this inspection method, since the through holes formed in the first steel plate are filled with the filling member, it is possible to suppress the decrease in the strength of the structure due to the through holes.

(5) The manufacturing method disclosed in the present specification is a method for manufacturing a structure having a steel plate concrete structure in which concrete is filled between a first steel plate and a second steel plate facing the first steel plate. The step of arranging the first steel plate and the second steel plate facing each other, the step of placing concrete between the first steel plate and the second steel plate, and the step of forming a through hole in the first steel plate. The step of forming and the columnar first waveguide member are arranged so that one end of the first waveguide member is inserted into the through hole and comes into contact with the concrete, and the columnar second waveguide member is arranged. The second waveguide member does not come into contact with the first waveguide member, one end of the second waveguide member is inserted into the through hole and comes into contact with the concrete, and the one end side of the first waveguide member. The impact provided on the first waveguide member after the step of arranging one of the end portion of the second waveguide member and the one end portion of the second waveguide member on the one end side so as to surround the other and the step of arranging the second waveguide member. After the step of striking the striking surface, which is a surface and has an outer dimension larger than the outer dimension of the one end of the first waveguide member, and the step of arranging the surface, the vibration of the second waveguide member is applied. It includes a step of measuring and a step of specifying an elapsed time from when the striking surface is impacted until the vibration having an amplitude equal to or larger than the reference amplitude is measured in the second waveguide member. According to this manufacturing method, a through hole is formed in the first steel plate, and the first waveguide member and the second waveguide member are brought into contact with concrete through a common through hole. Therefore, the distance between the first waveguide member and the second waveguide member varies as compared with the case where the first waveguide member and the second waveguide member are brought into contact with the concrete through separate through holes. By suppressing it, it is possible to suppress a decrease in inspection accuracy.

(6) The inspection jig disclosed in the present specification is used for inspecting a structure having a steel plate concrete structure in which concrete is filled between the first steel plate and the second steel plate facing the first steel plate. An inspection jig to be used, which is a columnar first waveguide member having a striking surface having an outer dimension larger than the outer dimension of the first surface provided at one end, and a columnar one provided at one end. A second waveguide having a second surface is provided, and the first waveguide has an opening in the first surface, extends in the axial direction of the first waveguide, and has the first surface. A vacancy extending between the striking surface and a communication hole located on the outer periphery of the vacancy of the first waveguide member and communicating with the outside of the first waveguide member are formed. The second waveguide member is formed to have a main body portion arranged inside the vacancies and a protruding portion protruding from the main body portion to the outside of the first waveguide member through the communication hole. The second waveguide member has a first position in which the second surface projects from the first surface in the axial direction of the first waveguide member and in the axial direction of the first waveguide member. The first surface and the second surface are arranged at the same position, and the second waveguide member can swing between the second position where the first waveguide member does not come into contact with the first waveguide member. According to this inspection jig, the first surface of the first waveguide member and the second surface of the second waveguide member are inserted into a common through hole formed in the first steel plate and brought into contact with concrete. A state in which the first and second waveguides do not come into contact with each other because the first and second surfaces come into contact with the concrete and the second waveguide swings to the second position. Can be.

The techniques disclosed in the present specification can be realized in various forms, for example, an inspection device for a structure having a steel plate concrete structure, a computer program for realizing the functions of the inspection device, and a computer thereof. It can be realized in the form of a non-temporary recording medium or the like on which the program is recorded.

Explanatory drawing which shows schematic structure | structure 100 of SC structure Explanatory drawing which shows schematic structure of inspection system 400 Front view of inspection jig 200 Flow chart showing the method of measuring the thickness of concrete 20 Graph showing the determination method of the structure 100

A. First Embodiment:
A-1. Structure 100 of steel plate concrete structure:
FIG. 1 is an explanatory view schematically showing the structure of the structure 100 of the steel plate concrete structure (hereinafter referred to as “SC structure”) in the present embodiment. FIG. 1 shows XYZ axes that are orthogonal to each other to specify the direction. In the present specification, for convenience, the X-axis positive direction is referred to as the right side, the X-axis negative direction is referred to as the left side, the Y-axis positive direction is referred to as the front side, the Y-axis negative direction is referred to as the rear side, and the Z-axis positive direction is referred to. Is referred to as the upper side, and the negative direction of the Z axis is referred to as the lower side. The same applies to FIGS. 2 and later.

In the structure 100 having an SC structure, the inner surface 16 of the first steel plate 10 and the inner surface 36 of the second steel plate 30 formed as an outer frame are arranged so as to face each other, and are located between the first steel plate 10 and the second steel plate 30. It is formed by placing concrete 20. FIG. 1A shows a structure 100 in which no gap is formed between the first steel plate 10 and the concrete 20. As shown in FIG. 1A, the first steel plate 10 is arranged so that the inner surface 16 is perpendicular to the vertical direction, and the stud 12 is fixed to the inner surface 16 by welding. Further, the second steel plate 30 is arranged so that the inner surface 36 is perpendicular to the vertical direction, and the stud 32 is fixed to the inner surface 36 by welding. In the structure 100 of the SC structure, the stud 12 fixed to the first steel plate 10 and the stud 32 fixed to the second steel plate 30 are restrained by the concrete 20, so that the first steel plate 10 and the second steel plate 30 are restrained. And are fixed.

FIG. 1B shows a structure 100 in which a slight gap 22 is formed between the first steel plate 10 and the concrete 20. The slight voids 22 are generated, for example, by the drying shrinkage of the filled concrete 20. In the design of the structure 100 of the SC structure, the generation of the slight voids 22 is considered in advance, and the generation of the slight voids 22 often does not pose a problem of the structure 100 of the SC structure.

FIG. 1C shows a structure 100 in which a gap 24 larger than a slight gap 22 is formed between the first steel plate 10 and the concrete 20. The large void 24 is generated, for example, due to insufficient filling of the concrete 20 or the like. If a large gap 24 is generated, the strength required for designing the structure 100 of the SC structure cannot be maintained, which may cause a problem. In the present embodiment, by measuring the thickness of the concrete 20 using the through holes 14 formed in the first steel plate 10, whether the gaps 22 and 24 are formed between the first steel plate 10 and the concrete 20. Inspect whether or not.

Next, the thickness measurement of the concrete 20 will be described with reference to FIGS. 2 and 3. In this embodiment, the thickness of the concrete 20 is measured using the inspection system 400. FIG. 2 is an explanatory diagram schematically showing the configuration of the inspection system 400. The inspection system 400 includes an inspection jig 200 and a personal computer (hereinafter referred to as "PC") 300. FIG. 2 shows a cross-sectional view of the inspection jig 200, a system configuration of the PC 300, and a structure 100 similar to that of FIG. 1 (a). FIG. 3 is a front view of the inspection jig 200.

As shown in FIGS. 2 and 3, the inspection jig 200 includes a waveguide 40, a waveguide 50, and an accelerometer 60. The waveguide 40 is an example of the first waveguide member, and the waveguide 50 is an example of the second waveguide member.

The waveguide 40 is a substantially columnar member, and is arranged so as to extend in the vertical direction. The waveguide 40 includes a first contact surface 44 and a striking surface 42. The first contact surface 44 is provided near the lower end of the waveguide 40. The lower end of the waveguide 40 near the first contact surface 44 has a substantially cylindrical shape. The striking surface 42 is a surface to which a hammer 70 or the like is applied, and is an upper end surface of the waveguide 40. The outer dimension R1 of the striking surface 42 is larger than the outer dimension R2 of the first contact surface 44. Specifically, the outer dimension R1 of the striking surface 42 is 2 of the outer dimension R2 of the first contact surface 44. It is more than doubled. The reason why the outer dimension R2 of the first contact surface 44 is made smaller than the outer dimension R1 of the striking surface 42 is that the opening area of the through hole 14 is made as narrow as possible so as not to deteriorate the structural performance of the first steel plate 10. The first contact surface 44 is an example of the first surface.

The waveguide 40 is formed with a hole 46 and a communication hole 48. The hole 46 is open to the first contact surface 44 and extends in the vertical direction. The upper end of the hole 46 reaches between the striking surface 42 of the waveguide 40 and the first contact surface 44. The communication hole 48 is formed in a tubular portion 47 located on the outer periphery of the hole 46. The communication hole 48 extends in the left-right direction and penetrates the waveguide 40 in the left-right direction. As a result, the hole 46 and the outside of the waveguide 40 are communicated with each other by the communication hole 48. The tubular portion 47 is an example of an outer peripheral portion.

The waveguide 40 is for transmitting the vibration wave generated by the impact on the striking surface 42 to the concrete 20 of the structure 100, so that the vibration wave of the specific frequency F is generated by the impact on the striking surface 42. In addition, the length in the vertical direction is adjusted. Specifically, the length in the vertical direction is adjusted so as to generate a vibration wave having a single frequency and having a relatively low frequency (for example, 2 kHz to 20 kHz).

The waveguide rod 50 is a member having a T-shape when viewed in the left-right direction. The waveguide 50 is for receiving the vibration wave transmitted from the waveguide 40 to the concrete 20 and reflected on the lower surface of the concrete 20 in contact with the second steel plate 30, and is for receiving the main body 52 and the pressing plate. It is equipped with 56. The main body 52 is a columnar member, and is arranged inside the pores 46 of the waveguide 40 so as to extend in the vertical direction. That is, the main body 52 of the waveguide 50 is surrounded by the tubular portion 47 of the waveguide 40, and is arranged coaxially with the waveguide 40. The main body 52 includes a second contact surface 54 which is a lower end surface of the main body 52. The outer dimension R3 of the main body 52 is smaller than the inner dimension R4 of the tubular portion 47, and an damping agent 72 such as Styrofoam is interposed between the main body 52 and the tubular portion 47. Therefore, the waveguide 40 and the waveguide 50 are kept in non-contact in the front-rear direction and the left-right direction, and the direct transmission of the vibration wave from the waveguide 40 to the waveguide 50 is suppressed. The second contact surface 54 is an example of the second surface.

The pressing plate 56 is a flat plate-shaped member, and is arranged so as to extend in the left-right direction in the communication hole 48 of the waveguide 40. The pressing plate 56 is for pressing the main body 52 against the concrete 20, the central portion in the left-right direction is fixed to the upper end of the main body 52, and the right end portion is from the main body 52 through the communication hole 48. The left end portion protrudes to the right side of the tubular portion 47, and the left end portion protrudes to the left side of the tubular portion 47 through the communication hole 48 from the main body portion 52. The central portion of the pressing plate 56 in the left-right direction is fixed to the upper end of the main body portion 52 inside the holes 46 of the waveguide 40, whereby the waveguide rod 50 cannot be taken out from the waveguide 40. .. The pressing plate 56 is an example of a protruding portion.

As shown in FIG. 3, the vertical width of the communication hole 48 is larger than the vertical width of the pressing plate 56, and the waveguide 50 instructs the waveguide 40 to swing in the vertical direction. Has been done. Specifically, in the waveguide rod 50, the second contact surface 54 of the main body 52 protrudes below the first contact surface 44 of the waveguide 40 when the waveguide 50 is not in contact with the concrete 20. Supported in position.

When measuring the thickness of the concrete 20, the waveguide 40 is arranged so that the axial direction of the waveguide 40 is in the vertical direction with respect to the structure 100, and the first contact surface 44 of the waveguide 40 Is inserted into the through hole 14 and comes into contact with the concrete 20. As a result, the second contact surface 54 of the main body 52 is inserted into the through hole 14 and comes into contact with the concrete 20, and the waveguide 50 is the second contact surface 54 of the main body 52 and the first of the waveguide 40. The contact surface 44 swings to a second position located at the same position in the vertical direction, whereby the waveguide 40 and the waveguide 50 are not in contact with each other in the vertical direction (see FIG. 2).

The accelerometer 60 is attached to the pressing plate 56. The accelerometer 60 measures the vibration of the waveguide 50. Specifically, among the vibrations generated in the waveguide 50 due to the transmission of the vibration waves from the concrete 20, the amplitude of the vibrations at the specific frequency F is measured. The accelerometer 60 is connected to the PC 300 and transmits data indicating the measured amplitude to the PC 300.

The PC 300 includes a control unit 80, an input unit 83, an operation unit 84, a display unit 85, and a communication unit 86. The control unit 80, the input unit 83, the operation unit 84, the display unit 85, and the communication unit 86 are connected to each other via a bus or the like. The control unit 80 includes a CPU 81 and a memory 82.

The input unit 83 is hardware that is connected to the accelerometer 60 and temporarily stores the data received from the accelerometer 60 in the memory 82. The operation unit 84 has, for example, a mouse or a keyboard (not shown) and receives various instructions by the user. The display unit 85 has, for example, a liquid crystal display and displays various screens. The communication unit 86 is hardware that communicates with other devices by a wired communication method or a wireless communication method.

A control program for controlling the PC 80, various settings, initial values, and the like are stored in the memory 82. The memory 82 is also used as a work area when the CPU 81 executes various programs and as a storage area for data transmitted from the accelerometer 60. The CPU 81 realizes each function of the control unit 80 by executing various programs read from the memory 82.

A-2. Method of measuring the thickness of concrete 20:
Next, a method for measuring the thickness of the concrete 20 in the present embodiment will be described. FIG. 4 is a flowchart showing a method of measuring the thickness of the concrete 20 in the present embodiment. The method for measuring the thickness of the concrete 20 is an example of an inspection method for the structure 100 having an SC structure.

First, a through hole 14 is formed in the first steel plate 10 (S110). The through hole 14 is formed after the concrete 20 is cast. The through hole 14 is formed by using, for example, a hole saw or a core drill. In the present embodiment, the structure of the first steel plate 10 is formed by making the opening area of the through hole 14 as narrow as possible in correspondence with the outer dimension R2 of the first contact surface 44 of the waveguide 40 inserted into the through hole 14. It is possible to suppress the deterioration of performance. However, when the through hole 14 is already formed in the first steel plate 10 for another purpose, it is not always necessary to execute the process of forming the through hole 14 in the first steel plate 10.

Next, the inspection jig 200 is arranged (S120). As described above, the first contact surface 44 of the waveguide 40 is inserted into the through hole 14 and comes into contact with the concrete 20. When the first contact surface 44 of the waveguide 40 is inserted into the through hole 14, the second contact surface 54 of the main body 52 is inserted into the through hole 14 and comes into contact with the concrete 20. When the pressing plate 56 is pressed toward the concrete 20, the second contact surface 54 of the waveguide rod 50 is surely in contact with the concrete 20.

Next, an impact is applied to the impact surface 42 of the waveguide 40 (S130). Specifically, in a state where the first contact surface 44 of the waveguide 40 is in contact with the concrete 20, a hammer 70 or the like applies a blow to the striking surface 42 of the waveguide 40. As a result, a vibration wave having a specific frequency F corresponding to the vertical length of the waveguide 40 is generated. The oscillating wave is amplified by the outer dimension R2 of the first contact surface 44 being smaller than the outer dimension R1 of the striking surface 42 while being transmitted downward through the waveguide 40, and is directly transmitted to the concrete 20. To.

Next, the vibration of the waveguide rod 50 is measured (S140). The vibration of the waveguide 50 is measured by the accelerometer 60, and data indicating the amplitude of the vibration of the specific frequency F of the waveguide 50 is transmitted to the PC 300.

Next, the elapsed time ΔT from when the impact surface 42 of the waveguide 40 is impacted until the waveguide 50 vibrates with an amplitude equal to or larger than the reference amplitude is specified (S150). The elapsed time ΔT is specified by the control unit 80 of the PC 300. Data indicating the reference amplitude is stored in the memory 82 of the PC 300, and the control unit 80 uses the amplitude of vibration of the specific frequency F indicated by the data received from the accelerometer 60 (hereinafter referred to as “specific amplitude”) and the reference. Compare with amplitude. For example, the control unit 80 determines the measurement timing T1 (FIG. 5A) in which the specific amplitude exceeds the reference amplitude for the first time after the oscillation timing T0 (see FIG. 5) in which the impact surface 42 of the waveguide 40 is impacted. (See) is specified, and the elapsed time ΔT1, which is the time difference between the oscillation timing T0 and the measurement timing T1, is specified.

Next, the structure 100 is determined using the elapsed time ΔT (S160). FIG. 5 is a graph showing a method for determining the structure 100. FIG. 5 shows the elapsed time ΔT1 measured using the structure 100 (see FIG. 1A) in which no gap is formed between the first steel plate 10 and the concrete 20, and the first steel plate 10 and the concrete. The elapsed time ΔT2 measured using the structure 100 (see FIG. 1B) in which a slight gap 22 is formed between the 20 and the large gap 24 between the first steel plate 10 and the concrete 20. The elapsed time ΔT2 measured using the structure 100 in which the is formed (see FIG. 1C) is shown.

A structure 100 in which no gap is formed between the first steel plate 10 and the concrete 20, a structure 100 in which a slight gap 22 is formed between the first steel plate 10 and the concrete 20, and a first steel plate. In the structure 100 in which a large gap 24 is formed between the 10 and the concrete 20, the thickness of the concrete 20 becomes thinner in this order, and the elapsed time ΔT1 and the elapsed time ΔT2 correspond to this. The time ΔT3 is shortened in this order. Therefore, for example, the elapsed time ΔT1 of the structure 100 in which no void is formed between the first steel plate 10 and the concrete 20 is determined by measurement, simulation, or the like, and the normal elapsed time range is centered on the determined elapsed time ΔT1. Set ΔHT. Whether or not there is an abnormality in the structure 100 can be determined by whether or not the elapsed time ΔT measured by using the structure 100 is included in the normal elapsed time range ΔHT.

When the elapsed time ΔT is included in the normal elapsed time range ΔHT (S160: YES) as in the elapsed time ΔT2, it is determined that the structure 100 is normal. On the other hand, when the elapsed time ΔT is not included in the normal elapsed time range ΔHT (S160: NO) as in the elapsed time ΔT3, it is determined that the structure 100 is abnormal. In this case, the structure 100 is repaired (S170). Specifically, a filler such as cement paste or mortar is injected into the voids 22 and 24.

Next, the through hole 14 is repaired (S180). The through hole 14 is repaired after the elapsed time ΔT is specified and the waveguide 40 and the waveguide 50 are pulled out from the through hole 14. As shown in FIG. 1A, in the repair of the through hole 14, the through hole 14 is filled with a metal filling member 18, and the cover sheet 19 is attached to the outer surface 17 in the range including the through hole 14. This completes the method for measuring the thickness of the concrete 20.

A-3. Effect of this embodiment:
As described above, in the method for measuring the thickness of the concrete 20 of the present embodiment, the waveguide 40 and the waveguide 50 penetrate the same through hole 14 and come into contact with the concrete 20. Therefore, the distance between the waveguide 40 and the waveguide 50 varies as compared with the case where the waveguide 40 and the waveguide 50 penetrate the separate through holes and come into contact with the concrete 20. Is suppressed, so that a decrease in measurement accuracy can be suppressed. Further, the number of through holes 14 formed in the first steel plate 10 can be reduced.

Further, in the method for measuring the thickness of the concrete 20 of the present embodiment, a through hole 14 is formed in the first steel plate 10, and the waveguide 40 and the concrete 20 are brought into contact with each other through the through hole 14, and the waveguide 40 is formed. The vibration wave generated by the impact on the impact surface 42 is directly transmitted from the waveguide 40 to the concrete 20. Further, the waveguide 50 and the concrete 20 are brought into contact with each other through the through hole 14, and the vibration wave transmitted to the concrete 20 is directly transmitted from the concrete 20 to the waveguide 50. Therefore, as compared with the case where the vibration wave is transmitted through the first steel plate 10, the attenuation of the vibration wave by the first steel plate 10 is suppressed, and the deterioration of the measurement accuracy can be suppressed.

Further, in the method for measuring the thickness of the concrete 20 of the present embodiment, the outer dimension R2 of the first contact surface 44 of the waveguide 40 inserted into the through hole 14 is the outer dimension R1 of the striking surface 42 of the waveguide 40. Smaller than Therefore, the opening area of the through hole 14 can be narrowed as compared with the case where the outer dimension R2 and the outer dimension R1 are equal, and the decrease in strength of the structure 100 due to the formation of the through hole 14 in the first steel plate 10 is suppressed. can do. Further, as compared with the case where the outer dimensions R2 and the outer dimensions R1 are equal, the amplitude of the vibration wave generated by the impact of the waveguide 40 on the impact surface 42 can be amplified and transmitted to the concrete 20, and the vibration can be transmitted. The duration of the wave can be extended.

Further, in the method for measuring the thickness of the concrete 20 of the present embodiment, when measuring the vibration of the waveguide 50, the vibration of the specific frequency F corresponding to the vertical length of the waveguide 40 is measured. Therefore, the vibration of the waveguide 50 caused by the impact of the waveguide 40 on the impact surface 42 can be accurately measured. Further, since the specific frequency F is adjusted to be a relatively low frequency, the duration of the oscillating wave can be lengthened.

Further, in the method for measuring the thickness of the concrete 20 of the present embodiment, since the waveguide 50 has the pressing plate 56, the waveguide 50 can be surely brought into contact with the concrete 20.

Further, in the method for measuring the thickness of the concrete 20 of the present embodiment, the through hole 14 provided in the first steel plate 10 is filled with the filling member 18, so that after the thickness of the concrete 20 is measured, the structure 100 It is possible to suppress a decrease in strength.

B. Modification example:
The technique disclosed in the present specification is not limited to the above-described embodiment, and can be transformed into various forms without departing from the gist thereof. For example, the following modifications are also possible.

In the above embodiment, an example in which the gaps 22 and 24 are formed between the first steel plate 10 and the concrete 20 is shown, but the gaps 22 and 24 are formed between the second steel plate 30 and the concrete 20. You may.

Further, the voids 22 and 24 may be formed inside the concrete 20. In this case, since the vibration wave transmitted to the concrete 20 is transmitted so as to avoid the voids 22 and 24, the elapsed time ΔT is longer than that in the case where the voids 22 and 24 are not formed inside the concrete 20. Become. Even in this case, it is possible to inspect whether or not the structure 100 has an abnormality depending on whether or not the elapsed time ΔT measured by using the structure 100 is included in the normal elapsed time range ΔHT.

10: 1st steel plate 14: Through hole 18: Compensating member 20: Concrete 22, 24: Void 30: 2nd steel plate 40: Waveguide 42: Strike surface 44: 1st contact surface 46: Vacancy 47: Cylindrical part 48: Communication hole 50: Waveguide rod 52: Main body 54: Second contact surface 56: Pressing plate 60: Accelerometer 72: Attenuator 100: Structure 200: Inspection jig T0: Oscillation timing T1: Measurement timing ΔT : Elapsed time ΔHT: Normal elapsed time range

Claims (6)

A method for inspecting a structure of a steel plate concrete structure in which concrete is filled between a first steel plate and a second steel plate facing the first steel plate.
The step of forming a through hole in the first steel sheet and
The columnar first waveguide member is arranged so that one end of the first waveguide member is inserted into the through hole and comes into contact with the concrete, and the columnar second waveguide member is placed in the second waveguide. The member does not come into contact with the first waveguide member, one end of the second waveguide member is inserted into the through hole and comes into contact with the concrete, and the end portion on the one end side of the first waveguide member and A step of arranging the second waveguide member so that one of the ends on one end side surrounds the other.
After the step of arranging, a step of striking the striking surface provided on the first waveguide member and having an outer dimension larger than the outer dimension of one end of the first waveguide member. When,
After the arranging step, a step of measuring the vibration of the second waveguide member and
An inspection method comprising a step of specifying an elapsed time from the time when an impact is applied to the impact surface until the vibration having an amplitude equal to or larger than a reference amplitude is measured in the second waveguide member. The inspection method according to claim 1.
The measuring step is a step of measuring the vibration of a specific frequency corresponding to the length from one end of the first waveguide member in the axial direction to the striking surface. The inspection method according to claim 1 or 2.
The first waveguide member
A hole that opens at one end of the first waveguide member, extends in the axial direction of the first waveguide member, and reaches between the one end of the first waveguide member and the striking surface.
A communication hole located on the outer peripheral portion of the hole of the first waveguide member and communicating between the hole and the outside of the first waveguide member is formed.
The second waveguide has a main body portion arranged inside the vacancies and a protruding portion protruding from the main body portion to the outside of the first waveguide member through the communication hole.
The step of arranging is a step of arranging the second waveguide member by bringing the second waveguide member into contact with the concrete by pressing the protruding portion toward the concrete side. The inspection method according to any one of claims 1 to 3, and further.
An inspection method comprising a step of removing the first waveguide member and the second waveguide member from the through hole and filling the through hole with a supplement member after the measurement step. A method for manufacturing a structure having a steel plate concrete structure in which concrete is filled between a first steel plate and a second steel plate facing the first steel plate.
A step of arranging the first steel plate and the second steel plate so as to face each other,
The process of placing concrete between the first steel plate and the second steel plate, and
The step of forming a through hole in the first steel sheet and
The columnar first waveguide member is arranged so that one end of the first waveguide member is inserted into the through hole and comes into contact with the concrete, and the columnar second waveguide member is placed in the second waveguide. The member does not come into contact with the first waveguide member, one end of the second waveguide member is inserted into the through hole and comes into contact with the concrete, and the end portion of the first waveguide member on the one end side is used. A step of arranging the second waveguide member so that one of the ends on one end side surrounds the other.
After the step of arranging, a step of striking the striking surface provided on the first waveguide member and having an outer dimension larger than the outer dimension of one end of the first waveguide member. When,
After the arranging step, a step of measuring the vibration of the second waveguide member and
A manufacturing method comprising a step of specifying an elapsed time from the time when an impact is applied to the impact surface until the vibration having an amplitude equal to or larger than a reference amplitude is measured in the second waveguide member. An inspection jig used for inspecting a structure of a steel plate concrete structure in which concrete is filled between a first steel plate and a second steel plate facing the first steel plate.
A first waveguide member that is columnar and has a striking surface having an outer dimension larger than the outer dimension of the first surface provided at one end.
It is provided with a second waveguide member which is columnar and has a second surface provided at one end.
The first waveguide member
A hole that opens in the first surface, extends in the axial direction of the first waveguide member, and reaches between the first surface and the striking surface.
A communication hole located on the outer peripheral portion of the hole of the first waveguide member and communicating between the hole and the outside of the first waveguide member is formed.
The second waveguide has a main body portion arranged inside the vacancies and a protruding portion protruding from the main body portion to the outside of the first waveguide member through the communication hole.
The second waveguide member has a first position in which the second surface projects from the first surface in the axial direction of the first waveguide member and the first position in the axial direction of the first waveguide member. An inspection jig in which a surface and the second surface are arranged at equal positions, and the second waveguide member can swing between a second position where the first waveguide member does not come into contact with the first waveguide member.

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