JP3514690B2 - Evaluation method of grout filling condition of concrete structure - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating the filling state of grout in a sheath of a concrete structure, in which a PC steel material is inserted. 2. Description of the Related Art Conventionally, as a method for evaluating the filling state of grout in a sheath in which a steel wire has been inserted in a concrete structure, for example, Japanese Patent Application Laid-Open No. 10-054140 is disclosed. There was what was shown in. This means that while hitting one end side of the concrete structure with an impact hammer, the elastic wave is incident on the structure and the elastic wave is received at the other end side,
The grout filling state was evaluated by analyzing the frequency distribution of the received elastic waves. Therefore, in the measurement, it is necessary to first record the waveform of the received elastic wave itself, then remove the influence of the surface wave, and then perform further frequency analysis. In addition, the frequency distribution evaluation had to be done by an experienced person making subjective judgments. That is, the frequency distribution obtained by this method is difficult to judge because various patterns appear, and furthermore, it changes depending on the characteristics of the sensor, so that it cannot be judged by anyone. [0003] The present invention has been made to solve the above-mentioned conventional drawbacks, and an object of the present invention is to provide a grout filling method for a concrete structure capable of easily evaluating the grout filling state. It is to provide a state evaluation method. [0004] A method for evaluating the filling state of grout in a concrete structure according to the present invention has the following configuration to achieve the above object. That is, [0005] [0006] According to the invention described in 請 Motomeko 1, filling state evaluation method grout concrete structures, in concrete structures, the filling state of the grout in the sheath PC steel material is inserted A method of evaluating, in the concrete structure, a sensor for detecting an elastic wave,
Three or more pieces are arranged along the PC steel material. Here, the concrete structure, along the PC steel material,
An elastic wave is input from one end or from the middle, and the arrival time of the elastic wave is measured by the sensor. Then, between the sensor determined by the arrival time and the sensor position of the elastic wave, the propagation velocity of the acoustic wave, before
Since the value depends on the degree of grout filling,
By checking the seeding rate, the state of filling of the grout between the sensors is evaluated. Namely, concrete alone, grout alone and in PC steel alone, respectively, different propagation velocity of the acoustic wave, in particular, PC steel is different from the concrete or grout, is fast propagation speed of the acoustic wave. However, in a concrete structure, when the inside of the sheath is filled with grout, the PC steel material inserted into the sheath is integrated with the grout, and the propagation speed of elastic waves in the PC steel material decreases, and the concrete structure When viewed as an object, the propagation speed of elastic waves is close to the propagation speed in concrete and grout. On the other hand, if the sheath is not partially or completely filled with grout,
The propagation speed of the elastic wave in the C steel material is the original speed of the PC steel material in the portion not filled with grout, and when viewed as a concrete structure, the propagation speed of the elastic wave is lower than the propagation speed in concrete or grout. It is a fast value. Thus, the PC inside the concrete structure
The propagation speed of the elastic wave propagating in the direction in which the steel material is disposed is
There is a difference between when the inside of the sheath is filled with grout and when it is not filled, that is, when the grout is partially or not completely filled. Therefore, a plurality of sensors for detecting elastic waves in the concrete structure are provided along the PC steel material, and elastic waves are input from one end or the middle of the concrete structure along the PC steel material, The arrival time of the elastic wave is measured by a sensor. And the arrival time of this elastic wave,
The state of grout filling between the sensors can be evaluated based on the propagation speed between the sensors determined by the sensor position. Further, prior Symbol sensor as along the PC steel, it is deployed three or more, thereby,
The state of grout filling between each of the deployed sensors can be evaluated, and the unfilled portion of grout can be identified. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a method for evaluating a grout filling state of a concrete structure according to the present invention will be described with reference to the drawings. FIGS. 1 and 2 show a first embodiment of a method for evaluating the state of grout filling of a concrete structure according to the present invention. FIG. 1 shows a concrete structure in which P
The filling degree of grout in the sheath into which the C steel material has been inserted (particularly, the case where the filling degree of the sheath is 100% filled with grout and the case where the filling degree is completely unfilled is 0%) and this concrete It is a graph which shows the relationship with the propagation speed of the elastic wave which propagates in the direction where the PC steel material was arrange | positioned in a structure. Here, when the filling degree of the grout is 100%, the propagation speed is about 3900 m / s, and when the filling degree of the grout is 0%, the propagation velocity is about 5000 m / s. . Thus, the propagation speed of the elastic wave clearly differs depending on the degree of filling of the grout. This is because the propagation speed of the elastic wave is about 4000 m / s for concrete alone and about 3800 m for grout alone.
/ S and PC steel material alone are about 5300 m / s, respectively, especially because PC steel material has a higher elastic wave propagation speed than concrete or grout. That is, in a concrete structure,
When the inside of the sheath is filled with grout, the PC steel material inserted through the sheath is integrated with the grout to form P steel.
The propagation speed of the elastic wave in the C steel material becomes slow, and when viewed as a concrete structure, the propagation speed of the elastic wave becomes a value close to the propagation speed in concrete or grout. On the other hand, when the grout is partially or not completely filled in the sheath, the propagation speed of the elastic wave in the PC steel material becomes the original speed of the PC steel material in the portion where the grout is not filled. When viewed as a concrete structure, the propagation speed of elastic waves is faster than that of concrete or grout. Thus, the propagation speed of the elastic wave propagating in the direction in which the PC steel material is disposed in the concrete structure and the arrival time of the elastic wave are determined when the inside of the sheath is filled with grout, that is, when the grout is filled. Is completely filled and when it is not filled, that is, when the grout is partially filled or not completely filled. Specifically, when the sheath is completely filled with grout, the propagation speed of the elastic wave is almost 39%.
When the grout is not filled at all, the propagation speed of the elastic wave becomes almost 5000 m / s, and when the grout is not partially filled,
Depending on the degree of filling, the propagation speed of the elastic wave is approximately 390
The value is an intermediate value between 0 m / s and approximately 5000 m / s. From this, the propagation speed in concrete structures,
Alternatively, the filling state of the grout can be easily evaluated by checking the arrival time determined by the propagation speed. FIG. 2 shows an embodiment in which the above-described method for evaluating the grout filling state of a concrete structure is applied to a concrete block 1 such as a bridge girder as a concrete structure. The concrete block 1 is formed such that the block body 2 extends straight in the left-right direction. Inside the concrete block 1, from one end side in the left-right direction, which is the longitudinal direction of the block body 2, toward the other end side. The sheath 3 is disposed in a curved manner. And in this sheath 3,
The PC steel material 4 is inserted, and the PC steel material 4 is tensioned, and the end portions 4a, 4a of the PC steel material 4 are fixed to the end surfaces 2a, 2a of the block main body 2 by the fixing tools 5, 5, respectively. ing. Further, in the sheath 3 through which the PC steel material 4 is inserted, a grout 6
Is filled. Therefore, in the method for evaluating the filling state of the grout 6, the concrete block 1 is provided with a plurality of sensors, such as AE (acoustic emission) sensors 7, for detecting elastic waves along the PC steel material 4. (In the illustrated embodiment, three or more AE sensors 7 are provided, specifically nine AE sensors 7). The AE sensors 7, 7 located on both sides of the AE sensors 7, 7 are provided on the fixing tools 5, 5,
The AE sensors 7, 7 located in the middle are provided on the side surface 1b of the concrete block 1. Here, an elastic wave is inputted by an impact hammer or the like from the fixing tool 5 on one end side, for example, the left end side, along the PC steel material 4 of the concrete block 1, and the AE sensors 7, , 7 are measured. That is, the signal of the elastic wave detected by each AE sensor is converted into an AE measurement system (not shown).
Is received by the AE measurement system,
Recording and analysis are performed. Note that the AE measurement system may be an elastic wave receiver that collectively performs signal reception, recording, and analysis. Alternatively, the AE measurement system may be configured to share the signal reception, recording, and analysis. And an arithmetic device such as a personal computer connected to the elastic wave receiver. The distance between the AE sensors 7, 7 determined by the arrival time of the elastic waves and the position of the AE sensors 7, 7
The filling state of the grout between the AE sensors 7, 7 can be easily evaluated by the above-described method based on the propagation speed of the elastic wave. At this time, if the distance between the AE sensors 7 is predetermined, the propagation speed is determined by the measured arrival time of the elastic wave, so there is no need to calculate the elastic wave propagation speed. The filling state of the grout between the AE sensors 7, 7 can be easily evaluated only by the wave arrival time. Further, three or more (more specifically, nine) AE sensors 7 are provided, and the filling state of the grout 6 between the AE sensors 7 and 7 can be evaluated. The unfilled portion of the grout 6 can be specified. As described above, the present evaluation method is different from the frequency analysis which tends to be a subjective judgment as in the conventional evaluation method, whereby the state of filling of grout is objectively measured by measuring the arrival time of the elastic wave. Can be determined. Here, since the longitudinal wave propagating in the concrete block 1 is much faster than the surface wave propagating on the surface of the concrete block 1, there is no possibility that the surface wave is measured in measuring the arrival time. it can. Moreover, in this evaluation method, only parameters such as time need be recorded.
The storage capacity of the acoustic wave receiver and the personal computer can be much smaller than before. According to such AE parameter measurement, simultaneous measurement of multiple channels is facilitated, and the measurement result of the multiple channels is
It can be confirmed immediately without going through any special process. Therefore, this evaluation method has extremely high inspection efficiency. FIG. 3 shows a second embodiment of the method for evaluating the filling state of grout in a concrete structure according to the present invention. The concrete block 11 as a concrete structure according to the second embodiment is different from the concrete block 1 according to the first embodiment in that the exposed end portions 4a and 4a of the PC steel 4 and the fixing tool are different from the concrete block 1 in the first embodiment. Protective concrete 12, 12 is cast to cover 5,5. The method of evaluating the filling state of the grout 6 is substantially the same as that of the first embodiment.
Of the nine AE sensors 7, 7 arranged along the line, the AE sensors 7, 7 located on both sides are arranged on the end faces 11a, 11a of the concrete block 1.
Then, the elastic wave is applied to the concrete block 11 by the PC.
The above-mentioned A on one end surface 11a which is one end side of the steel material
It is input from the vicinity of the E sensor 7. Other points are the same as those of the first embodiment, and have the same operation and effects as those of the first embodiment. However, the AE sensors 7, 7 on both sides may be provided on the side surface 11b instead of the end surface 11a of the concrete block 11, and similarly,
The elastic wave may be input from the side surface 11b instead of the end surface 11a of the concrete block 11. The present invention is not limited to the above-described embodiment, and various other modifications are possible. For example, the concrete structure is not limited to the concrete blocks 1 and 11 such as a bridge girder extending straight in the left-right direction, but may be curved side walls 21 such as a water storage tank as shown in FIG. In the side wall 21, the sheath 2 is provided so as to extend in the circumferential direction of the side wall 21.
2 and a PC steel material 23 is disposed in the sheath 22 thereof. In order to evaluate the filling state of the grout in the sheath 22, the AE sensors 7, 7
A plurality is provided in the circumferential direction of the side wall 21 so as to be along 3. Although not shown, a sheath and a PC steel material are disposed inside the side wall 21 so as to extend in the longitudinal direction of the side wall 21. For evaluation, a plurality of AE sensors may be provided in the longitudinal direction of the side wall 21 along the PC steel material. In the concrete blocks 1, 11 and the side walls 21, the elastic waves may not be inputted from one end side along the PC steel materials 4, 23, but may be inputted from the middle. In this case, the elastic wave propagates from the middle along the PC steel materials 4 and 23 toward each side, and the propagated elastic wave is
It is detected by AE sensors 7, 7 provided on each side. As is apparent from the above description, the method for evaluating the grout filling state of a concrete structure according to the present invention has the following effects. [0023] according to claim 1, according to the filling state evaluation method of grout concrete structure by examining the concrete structure, the propagation speed of the acoustic wave,
The grout filling state can be easily evaluated. In addition, the sensor is provided along the PC steel material.
In this way, three or more grouts are provided, and the filling state of the grout between each of the provided sensors can be evaluated, and the unfilled portion of the grout can be specified.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the relationship between the degree of grout filling and the propagation speed of elastic waves in the first embodiment of the method for evaluating the state of grout filling of a concrete structure according to the present invention. FIG. FIG. 2 is a schematic view of a concrete block in which an AE sensor is provided. FIG. 3 is a schematic view of a concrete block provided with an AE sensor according to a second embodiment of the method for evaluating the grout filling state of a concrete structure according to the present invention. FIG. 4 is a schematic view of a side wall provided with an AE sensor according to another embodiment of the method for evaluating the state of grout filling of a concrete structure according to the present invention. [Description of Signs] 1 concrete block (concrete structure) 3 sheath 4 PC steel 6 grout 7 AE sensor (sensor) 11 concrete block (concrete structure) 21 side wall (concrete structure) 22 sheath 23 PC steel

────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideaki Kitazono 3-13-3 Rokujo Omizo, Gifu City, Gifu Prefecture Inside Abe Industry Co., Ltd. (56) References JP-A-10-123105 (JP, A) JP-A Heisei 5-203631 (JP, A) JP-A-50-20784 (JP, A) JP-A-10-288608 (JP, A) JP-A-8-21824 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) E04G 21/12 104 G01N 29/00-29/28

Claims (1)

(57) Claims 1. A method for evaluating a filling state of grout in a sheath of a concrete structure through which a PC steel material is inserted, wherein an elastic wave is detected in the concrete structure. To secure
Deploy three or more sensors along the PC steel
And one end of the concrete structure along the PC steel material
From the side or middle, input the elastic wave to the sensor
Therefore, the arrival time of the elastic wave is measured and determined by the arrival time of the elastic wave and the sensor position.
The velocity of propagation of the elastic wave between the sensors
Since the value depends on the degree of filling of the route, its propagation speed
A grout filling state evaluation method for a concrete structure, wherein a grout filling state between the sensors is evaluated by examining a degree .