JPH1054140A - Filled state inspecting method for grout - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspecting method allowing an inspection with the simple work causing no peeling of asphalt, for example, in a structure that elastic waves are hardly fed directly to the end section of a reinforcing material such as a steel wire or a steel bar or a receiving piece is hardly fitted directly to the end section. SOLUTION: In a composite structure 1 such as a PC bridge, a long and rigid steel wire 5 is inserted into a hole 7a formed by a sheath pipe 7 provided in a rigid body 4, and a grout 8 is filled in the hole 7a. Elastic waves are transmitted from the one-end side of the reinforcing material 5, the elastic waves are received on the other side, and the filled state of the grout 8 is inspected. The surface 3a of the composite structure 1 along the longitudinal direction of the steel wire 5 is struck by an impact hammer 12 to feed elastic waves, and the propagated elastic waves are received by an AE sensor 14 from the surface 3a of the composite structure 1 along the longitudinal direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grout filling state inspection method for non-destructively inspecting a grout filling state around a steel material in a PC structure such as a PC bridge. More specifically, in a composite structure in which a long and rigid reinforcing material is inserted into a hole formed in a rigid body and grout is filled in the hole, an elastic wave is transmitted from one end side of the reinforcing material and the other. The present invention relates to a grout filling state inspection method for inspecting the grout filling state by receiving an elastic wave from an end side.

[0002]

2. Description of the Related Art In a PC structure by a post-tension method, a reinforcing material such as a steel wire or a steel rod is inserted into a hole of a concrete structure which has been solidified in a state where a hole has been formed in advance, and tension is applied to the reinforcing material. Multiply. Thereafter, grout is filled into the holes and solidified, thereby applying a compressive force to the entire PC structure.

However, it is difficult to sufficiently fill grout around a reinforcing material such as a steel bar, and sometimes the filling is unexpectedly insufficient. In such a case, since the strength of the PC structure at the initial design stage cannot be obtained, it is necessary to inspect the state of grout filling in the structure after construction.

As a method for inspecting the state of filling of grout, for example, a construction method described in Japanese Patent Application Laid-Open No. 4-182568 is known. According to the gazette, an ultrasonic transmitter is attached to one end of a steel bar exposed to the outside and an ultrasonic receiver is attached to the other end, and the characteristics of the received ultrasonic waves are analyzed to check the filling state of the grout. ing.

[0005] However, some PC structures, such as a PC bridge, are difficult to attach a transmitter or a receiver directly to the end of a reinforcing member. In this main PC bridge, asphalt and the like on the upper surface had to be removed even when the end of the steel wire was located near the upper surface. Further, since the PC bridges are continuously arranged at the end of the steel wire facing the end in the main girder direction, the receiver and the like cannot be directly attached to the steel wire.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional situation, the present invention is directed to a method in which an elastic wave is hardly incident directly on an end of a reinforcing material such as a steel wire or a steel rod, or a receiver is directly connected to the end. It is an object of the present invention to provide an inspection method capable of inspecting the filling state of grout by a simple operation that does not involve, for example, peeling of asphalt in a structure in which is difficult to attach.

[0007]

In order to achieve the above object, a method of inspecting the state of filling grout according to the present invention is characterized in that a long and rigid reinforcing material is inserted into a hole formed in a rigid body and the hole is inserted into the hole. A method for inspecting the filling state of the grout by transmitting an elastic wave from one end of the reinforcing material and receiving an elastic wave from the other end in a composite structure formed by filling grout in the reinforcing material, An elastic wave is incident on a surface of the composite structure along a longitudinal direction of the composite structure, or a propagating elastic wave is received from a surface of the composite structure along the longitudinal direction.

[0008] Here, the above-mentioned features include the following: "elastic waves are incident on the surface of the composite structure along the longitudinal direction of the reinforcing member;
Or reception of an elastic wave ”. Of course, depending on the situation, the case where “both the incidence and the reception of the elastic wave are performed through the surface” is also included.

In one embodiment of the present invention, the composite structure is a PC bridge having a horizontal portion and a vertical portion, wherein the hole is formed by a sheath tube embedded in the rigid body, Is a steel wire, and the incident side surface and the receiving side surface are side surfaces of the vertical portion.

When the incident side surface and the receiving side surface of the elastic wave are on the same surface of the composite structure, it is desirable to remove a surface wave of the received elastic wave that has passed through the rigid body surface. .

On the other hand, when the incident side and the receiving side of the elastic wave are opposite to each other on the composite structure,
Since the surface wave is greatly attenuated, it becomes easier to analyze the received elastic wave.

[0012]

Next, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, FIG.
As shown in FIG.
The present invention relates to a method for inspecting the filling state of grout in a PC bridge 1 which is a post-tension type composite structure realized by the tension described above. The PC bridge main body 4, which is a main part of the PC bridge 1 made of reinforced concrete, is formed in a substantially T-shape in front view having a horizontal portion 2 and a vertical portion 3. The steel wire 5 as a rigid reinforcing material is
A plurality of steel wires each having a diameter of about 10 mm are bundled, and each steel wire is stretched around both ends of the PC bridge main body 4 or between upper surfaces on both ends so as to detour below the vertical portion 3. .

As shown by reference numerals 1a and 1a in the longitudinal direction X of the vertical steel wire 5, a plurality of PC bridges 1 are arranged on a girder (not shown) with their ends close to each other. You. Further, with respect to a lateral direction Y orthogonal to the longitudinal direction X,
As shown by reference numeral 1b, a plurality of PC bridges are arranged close to each other. The PC bridges 1 arranged in the lateral direction Y are P
After the C bridge 1 is arranged, it is joined by a plurality of horizontal steel wires 6 penetrating in the horizontal direction Y.

The steel wire ends 5a of the vertical steel wires 5 are close to the other PC bridges 1 at both ends of the PC bridge 1 and mortar is embedded on the upper surface of the PC bridge 1, Since the asphalt is laid, it is difficult to receive and receive elastic waves to the vertical steel wire 5 and the like. An object of the present invention is to provide an inspection method capable of entering or receiving an elastic wave under such a circumstance by a simple operation that does not involve a separation operation of asphalt or the like.

In this PC bridge 1, after the PC bridge main body 4 is formed, the vertical steel wire 5 and the grout 8 shown in FIG. 3 are filled. In constructing the PC bridge 1, concrete is poured in a state where the sheath pipe 7 is arranged in advance, and the PC bridge main body 4 is solidified to form a hole 7a in the PC bridge main body 4. Next, the vertical steel wire 5 is inserted into the hole 7a, and a wedge 5b is driven into the steel wire end 5a with tension applied from both ends to apply a compressive force in the main girder direction of the PC bridge main body 4. . In this state, the grout 8 made of cement milk or the like is filled in the hole 7a and solidified. An object of the present invention is to detect a defective filling portion or a non-filled portion of the grout 8.

FIG. 2 is a logical block diagram of the inspection apparatus 10 according to the present invention. This inspection device 10
Generally, it has a personal computer 11, an impact hammer 12, an AE sensor 14, and the like. The personal computer 11 is connected with a central processing unit, a memory means 18 such as a RAM and a hard disk or a removable magnetic disk, an input device such as a keyboard and a mouse, and an output device such as a CRT display device and a printer via a data bus. By incorporating software and an extension board, a gate means 19 and an FFT means for obtaining a frequency spectrum by fast Fourier transform are realized.

The impact hammer 12 has an AE sensor near the hitting surface on the hammer for receiving a hitting signal. The incident elastic wave on the CH1 side received by the AE sensor of the impact hammer 12 is amplified by the first amplifier 15a, and the first A / D converter 1
The signal is stored in the memory means 18 of the personal computer 11 as a digital signal via 7a. In addition, vertical steel wire 5
The acoustic wave on the CH2 side received by the AE sensor 14 attached near the other end of the second A / D is amplified by the second amplifier 15b and then filtered by the filter 16 to remove noise by high-cut and low-cut second A / D. It is stored in the memory means 18 via the converter 17b. The signals of the incoming and outgoing elastic waves stored in the memory means 18 are directly transmitted to the C signal via the video circuit 21 as shown in FIG.
In addition to being displayed on the RT monitor 22, an unnecessary signal is removed by applying a time gate to the gate 19 and the FFT means 2
The frequency spectrum is obtained from 0. This frequency spectrum is also displayed via the video circuit 21 and the CRT monitor 22 as shown in FIG.

The impact by the impact hammer 12 and the mounting position of the AE sensor 14 are perpendicular to the surface of the PC bridge 1 along the longitudinal direction X near the steel wire end 5a, that is, the transverse direction Y of the vertical portion 3. The first side surface 3a or the second side surface 3b which is a surface. Since the first side surface 3a and the second side surface 3b are exposed to the outside even after the PC bridge 1 is installed, the impact hammer 1
2 and the attachment of the AE sensor 14 is very easy. In the present embodiment, the impact hammer 12 strikes the impact surface, that is, the incident side surface of the elastic wave and A
The receiving side surface of the elastic wave by the E sensor 14 is the first side surface 3a, which is the same side surface of the PC bridge 1 in both cases.

As shown in FIG. 3, the impact hammer 1
2 is transmitted to the AE sensor 14 side by the steel wire 5 and / or the sheath tube 7 and the first side surface 3a.
Is transmitted as a surface wave. The reception time t1 of the elastic wave received by the AE sensor 14 as the surface wave transmitted on the first side surface 3a is obtained by the following equation (a). t1 = L1 / v1 (a)

Here, as an example, if the linear distance L1 = 20 m between the impact position and the mounting position of the AE sensor 14 and the transmission speed v1 of the surface wave = 3030 m / s are substituted into the equation (a), the reception time t1 = It is about 6.6 ms.

If the grout 8 is insufficiently filled in the vicinity of the steel wire end 5a, the incident signal due to the impact of the impact hammer 12 and the signal received by the AE sensor 14 are transmitted along the route indicated by the distance L4. It is conceivable to make a detour so as to be transmitted to the end 5a once. L2
= 0.5m, L3 = 0.1m, the detour distance L4 is approximately 0.5m. Considering that the elastic wave is transmitted via the steel wire 5 in such a detour situation, the time t2 until the AE sensor 14 receives the post-hit signal is considered.
Is obtained by the following equation (b). t2 = L4 / v2 + L5 / v3 (b)

Here, the detour distance L4 = 0.5 m, the length (curve distance) along the curve of the vertical steel wire L5 = 22 m, the transmission speed v2 in concrete = 3030 m / s, the transmission through the vertical steel wire 5 Formula (b) using speed v3 = 2630 m / s as an example
, The reception time t of the elastic wave transmitted through the steel wire 5 etc.
2 = approximately 8.7 ms.

The incoming elastic wave S0 and the received elastic waves S1, S2
Is shown in FIG. As is clear from the figure, the first reception signal S1 before the reception time t2 of the elastic wave bypassing the vertical steel wire or the like includes many signals due to the surface wave and is affected by the filling degree of the grout. No signal considered. Therefore, by removing the first reception signal S1 before the detour elastic wave reception time t2 from the analysis signal in the FFT means 20 using the gate 19, it is possible to eliminate the influence of the surface wave. In this case, when the AE sensor 14 is located on the side opposite to the impact surface by the impact hammer 12, the surface wave S1 is less likely to be transmitted to the AE sensor, so that there is an advantage that the frequency analysis by the FFT means 20 becomes easy. In the present embodiment, the detour elastic wave reception time t2 is longer than the surface wave reception time t1, but depending on the material of the concrete 4 and the reinforcing material 5, the lengths of the two times t1 and t2 may be reversed. possible.

FIG. 5 shows the result of frequency analysis of the second received signal S2 of the received elastic wave by the FFT means.
Compared to the case of FIG. 1B filled with grout 100%, the case of FIG.
It was found that many high-frequency signals near 5 kHz were included. If the grout is not filled around the vertical steel wire, it is presumed that the high-frequency side signal component is less likely to be diffused to the PC bridge main body 4 and less attenuated. As described above, it is possible to inspect the filling state of the grout even if the elastic wave is directly incident on the reinforcing material such as a steel wire or the elastic wave is not directly received.

In practicing the present invention, first, the position of the vertical steel wire 5 is checked by a radar method or the like. In this case, a short pulse transmission wave having a pulse width of about 1 to 6 ns is radiated from the transmission antenna into the concrete PC bridge main body 4,
The wave reflected on the boundary surface between the concrete wire and the gap between the steel wire and the gap having a different dielectric constant is received by the receiving antenna, and the position of the vertical steel wire 5 is grasped. The approximate position of the vertical steel wire 5 obtained in this manner is marked, and AE is applied to the surface of one end of the PC bridge 1.
The sensor 14 is attached, and the surface on the other end is hit with the impact hammer 12. A surface wave is removed from the received elastic wave by the above-described procedure, and a frequency analysis and the like are performed to check the filling state of the grout.

Finally, another embodiment of the present invention will be described. In the above embodiment, when the elastic wave is incident,
Although the first side face 3a is hit by the impact hammer 12, a shock wave may be incident by a pulsar using PZT instead of the impact hammer 12, or an elastic wave may be incident by hitting a metal piece. I do not care.

In the above embodiment, the inspection method of the present invention was applied to a post-tension type PC structure in which a steel wire was placed in a steel wire 5 made of concrete and then filled with grout. The present invention may be applicable to a composite structure in which a long reinforcing material other than steel is inserted into a hole formed in the rigid body 4 and a grout other than cement, such as FRP, is filled. .

In the above embodiment, an elastic wave is incident on the surface of the composite structure along the longitudinal direction of the reinforcing member, and the elastic wave is received from the surface of the composite structure. However, if possible depending on the situation, either the input or the reception of the elastic wave may be performed directly via the end of a reinforcing material such as a steel wire.

In the above embodiment, when removing the influence of the surface wave, the first reception wave S1 before the bypass elastic wave reception time t2 was removed by using a time gate. However, the influence of the surface wave is removed. May be implemented such that the first received wave S1 is selected and removed or only the second received wave S2 is selected according to the waveform characteristics of the received elastic wave. The purpose of removing the first received wave S1 includes selection of only the second received wave S2. The removal of the first received signal S1 or the selection of the second received signal S2 can be realized by visual and manual operations, or by automatic removal and selection by parameters such as an integral value of the received signal exceeding a certain amount. Is also possible.

[0030]

As described above, according to the features of the method for inspecting the state of filling grout according to the present invention, it is difficult to directly apply an elastic wave to the end of a reinforcing material such as a steel wire or a steel rod. It has become possible to provide an inspection method capable of inspecting the filling state of grout by a simple operation that does not involve, for example, peeling of asphalt in a structure in which a receiver is difficult to directly attach to a part. As a result, the state of grout filling can be inspected simply and quickly, which can greatly contribute to improving the safety of existing structures.

Further, by making the incident side and the receiving side of the elastic wave on the same side and removing the surface wave, or making the incident side and the receiving side opposite to each other, the filling state of the grout can be improved. The effect of surface waves that do not contain information can be removed, making it possible to more accurately grasp the state of grout filling.

It should be noted that the reference numerals entered in the claims are merely for convenience of comparison with the drawings, and the present invention is not limited to the configuration of the attached drawings. .

[Brief description of the drawings]

FIG. 1A is a perspective view in which an intermediate portion of a PC bridge is omitted.
(B) is a side view of the left half of the PC bridge.

FIG. 2 is a logical block diagram of an inspection device according to the present invention.

FIG. 3 is a cross-sectional view of a PC bridge cut along a vertical steel wire.

FIG. 4 is a graph showing a relationship between time and intensity of an incident-side elastic wave and a receiving-side elastic wave.

FIG. 5A is a graph showing a frequency spectrum of a received elastic wave when grout is not filled,
(B) is a graph showing a frequency spectrum of a received elastic wave when grout is filled 100%.

[Description of Signs] 1 PC bridge 1a Vertical continuous bridge 1b Horizontal continuous bridge 2 Horizontal section 3 Vertical section 3a First side 3b Second side 4 PC bridge main body 5 Vertical steel wire 5a Steel wire end 5b Wedge 6 Cross steel wire 7 Sheath tube 7a Hole 8 Grout 10 Inspection device 11 Personal computer 12 Impact hammer 14 AE sensor 15a First amplifier 15b Second amplifier 16 Filter 17a First A / D converter 17b Second A / D converter 18 Memory means 19 Gate 20 FFT means 21 video circuit 22 CRT monitor X longitudinal direction Y lateral direction

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeto Nishimoto 1-1-18-14 Kitahorie, Nishi-ku, Osaka City Non-Destructive Inspection Co., Ltd. (72) Keiichi Tsuji 1-1-18-14 Kitahorie, Nishi-ku, Osaka City Non-Destructive Inspection Co., Ltd. (72) Inventor Susumu Ryuo 1-18-14 Kitahorie, Nishi-ku, Osaka-shi Non-Destructive Inspection Co., Ltd.

Claims (4)

[Claims] 1. A long and rigid reinforcing material (5) is inserted into a hole (7a) formed in a rigid body (4), and said hole (7) is inserted into said hole (7a).
In the composite structure (1) in which the grout (8) is filled in a), the elastic wave is transmitted from one end side of the reinforcing material (5) and the elastic wave is received from the other end side, so that the grout ( 8) A grout filling state inspection method for inspecting a filling state of 8), wherein the surface (3a, 3) of the composite structure (1) along the longitudinal direction (X) of the reinforcing material (5).
b) receives or propagates an elastic wave to the surface (3) of the composite structure (1) along the longitudinal direction (X).
a, 3b) a grout filling state inspection method. 2. The composite structure according to claim 1, wherein the incident side and the receiving side of the elastic wave are on the same side of the composite structure.
The method according to claim 1, wherein a) removes a surface wave (S1) that has passed through the surface (3a) of the composite structure (1) among the received elastic waves (S1, S2). Grout filling state inspection method. 3. The side face (3a, 3b) of the composite structure (1) wherein the side face (3a) and the side face (3b) of receiving the elastic wave are opposite to each other. 3. The grout filling state inspection method according to 1. 4. The composite structure is a PC bridge (1) having a horizontal part (2) and a vertical part (3), and said hole (7).
a) a sheath tube (7) embedded in said rigid body (4)
The reinforcing member is a steel wire (5), and the incident side surface and the receiving side surface are side surfaces (3a, 3b) of the vertical portion (3). The grout filling state inspection method described in the above.