Method, system and program for evaluating the durability of concrete poles

Abstract

We provide a system for evaluating the durability of concrete poles such as utility poles. Measurement means (201, 202) for measuring the propagation characteristics of ultrasonic waves in a concrete pole (1) by bringing a probe into contact with the concrete pole; A system (101) for evaluating the durability of a concrete pole, comprising: a calculation means (322) for calculating the durability of the concrete pole by comparing the propagation characteristics with an evaluation criterion for the durability of the concrete pole.

Description

[Technical Field]

[0001] The present invention relates to a method for evaluating the durability of a concrete pole, a system for evaluating the durability of a concrete pole, and a program for evaluating the durability of a concrete pole. [Background technology]

[0002] Concrete poles are used as power distribution poles and telephone communication poles. Concrete poles are widely used for stringing electric wires. In recent years, electric wires have been buried for aesthetic reasons. However, concrete poles are less expensive than buried poles. For this reason, concrete poles are still widely used for expanding, adding, and removing wiring, as well as for disaster recovery.

[0003] As a method for evaluating concrete poles that have been installed for a certain period of time, a comprehensive evaluation is carried out based on the level of deterioration for each type of deterioration and deformation such as cracks and surface roughness, as well as the appearance, etc. In addition, documents such as Patent Documents 1 and 2 are also disclosed.

[0004] Patent Document 1 discloses a utility pole deterioration diagnosis device comprising: a ring-shaped frame arranged along the outer periphery of a utility pole and connected to one end by a hinge; a plurality of fixing springs provided at a plurality of mutually spaced locations around the frame, each protruding radially inward and applying an elastic force between the frame and the utility pole; a pair of sensor mounting parts provided on the frame opposite each other and movable in the circumferential direction; deterioration diagnosis sensors supported on the sensor mounting parts so as to be movable in the radial direction of the frame; sensor pressing means for moving the deterioration diagnosis sensors on the sensor mounting parts in the radial direction of the frame; and drive means for moving the pair of sensor mounting parts in the circumferential direction of the frame while maintaining them facing each other.

[0005] Patent Document 2 discloses a method for determining the health of a utility pole or telephone pole, characterized by comprising the steps of: (a) restraining the vicinity of the upper end of the utility pole or telephone pole; (b) striking the utility pole or telephone pole to vibrate it; (c) measuring the natural frequency of the vibrated utility pole or telephone pole; and (d) determining the health of the utility pole or telephone pole based on the natural frequency. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Publication No. 03-072352 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-250682 Summary of the Invention [Problem to be solved by the invention]

[0007] Concrete poles are widely used for power transmission and distribution lines. However, the number of poles that have been in use for a long time is increasing. According to national policy, concrete distribution poles that are over 65 years old are considered for replacement.

[0008] Evaluation methods that take utility poles into account, such as those described in Patent Documents 1 and 2, are being considered. However, while these may be able to detect obvious abnormalities in utility poles, such as when excessive loads are placed on them immediately after installation or when there are initial defects, they do not provide an indicator of how long the poles will be destroyed, and therefore cannot be used to evaluate how long they can be used.

[0009] Furthermore, the Concrete Pole Diagnostician's Guidebook proposes that the current evaluation criteria for replacing distribution poles be determined by taking into account the "deterioration level (usually IV or V)" established for each "type of deterioration and alteration" such as cracks and surface roughness, as well as the "surrounding environment" such as salt damage and frost damage. This evaluation standard is limited to the extent that can be investigated visually from the outside, and does not include evaluation using non-destructive testing equipment. Using this evaluation standard, a 65-year-old distribution pole with no visible deterioration and a "deterioration level I" would be judged to be subject to "monitoring" and would not be subject to replacement.

[0010] Under these circumstances, there is a need to quantitatively explain the durability of each concrete pole. However, even if conventional evaluation standards are applied, it may be possible to evaluate the difference from a normal product, but it is not possible to evaluate the durability that serves as a guide to the so-called lifespan. Under these circumstances, the object of the present invention is to provide a method for evaluating the durability of concrete poles such as utility poles. [Means for solving the problem]

[0011] The present inventors have conducted extensive research to solve the above problems and have found that the following inventions meet the above objectives, thereby completing the present invention.

[0012] <1> a step of measuring the propagation characteristics of ultrasonic waves in the concrete pole by a measuring means for measuring the propagation characteristics of ultrasonic waves by bringing a probe into contact with the concrete pole; A method for evaluating the durability of a concrete pole, comprising a step of calculating the durability of the concrete pole by comparing the propagation characteristics with an evaluation criterion for the durability of the concrete pole. <2> The durability evaluation criteria are based on the propagation characteristics of ultrasonic waves obtained by repeatedly loading a reference concrete pole from the time of manufacture to the time of destruction. <1> The method described below. <3> The measuring step is performed by bringing the probe of the ultrasonic measuring means into contact with a plurality of measurement positions in the height direction and / or the circumferential direction of the concrete pole. <1> or <2> The method described below. <4> a measuring means for bringing a probe into contact with a concrete pole to measure the propagation characteristics of ultrasonic waves in the concrete pole; A system for evaluating the durability of a concrete pole, comprising: a calculation means for calculating the durability of the concrete pole by comparing the propagation characteristics with an evaluation standard for the durability of the concrete pole. <5> This is a program for evaluating the durability of concrete poles. A program for causing a computer to function as a calculation means for calculating the durability of a concrete pole by comparing the propagation characteristics of ultrasonic waves in the concrete pole, obtained using a measurement means for measuring the propagation characteristics of ultrasonic waves by contacting a probe with the concrete pole, with an evaluation standard for the durability of the concrete pole. [Effects of the Invention]

[0013] According to the present invention, the durability of concrete poles such as utility poles can be evaluated. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram illustrating an embodiment of an evaluation system of the present invention. [Figure 2] FIG. 1 is a flow chart showing an example of an evaluation method of the present invention. [Figure 3] FIG. 1 is a schematic diagram showing test conditions of the present invention. [Figure 4] FIG. 1 is a schematic diagram of a test conducted to obtain the findings of the present invention. [Figure 5] 10 is a graph showing measurement results of ultrasonic wave propagation characteristics in a bending test of a concrete pole. [Figure 6] 1 is a graph showing strains caused by bending tests of concrete poles. DETAILED DESCRIPTION OF THE INVENTION

[0015] The following describes in detail an embodiment of the present invention, but the following description of the constituent elements is one example (typical example) of an embodiment of the present invention, and the present invention is not limited to the following content unless the gist of the present invention is changed. Note that when the expression "to" is used in this specification, it is used as an expression that includes the numerical values ​​before and after it.

[0016] [Method for evaluating concrete poles according to the present invention] The evaluation method of the present invention is a method for evaluating the durability of a concrete pole, comprising the steps of measuring the propagation characteristics of ultrasonic waves in the concrete pole using an ultrasonic measuring device with a probe in contact with the concrete pole, and calculating the durability of the concrete pole by comparing the propagation characteristics with evaluation criteria for the durability of the concrete pole.

[0017] [Concrete pole evaluation system of the present invention] The concrete pole evaluation system of the present invention includes an ultrasonic measuring device for measuring the propagation characteristics of ultrasonic waves in the concrete pole by bringing a probe into contact with the concrete pole; and a calculation means for calculating the durability of the concrete pole by comparing the propagation characteristics with an evaluation standard for the durability of the concrete pole.

[0018] [Concrete pole evaluation system of the present invention] The concrete pole evaluation program of the present invention is a program for evaluating the durability of a concrete pole, and is a program for causing a computer to function as a calculation means for calculating the durability of the concrete pole by comparing the ultrasonic propagation characteristics in the concrete pole, obtained using an ultrasonic measuring device with a probe in contact with the concrete pole, with evaluation criteria for the durability of the concrete pole.

[0019] In the present application, the evaluation method of the present invention can be performed by the evaluation system of the present invention, and the program of the present invention can be used for the evaluation method of the present invention or the evaluation system of the present invention. In the present application, corresponding configurations can be used mutually.

[0020] The inventors have investigated methods for evaluating the deterioration index of concrete poles, with the aim of establishing quantitative criteria for determining the deterioration of concrete poles such as utility poles that need to be replaced. As a result, they have succeeded in capturing the time-series changes in the deterioration of concrete poles by analyzing the propagation characteristics, such as the propagation speed of ultrasonic waves, of erected concrete poles, and have found that this can be used as a method for determining the deterioration of aged concrete poles.

[0021] By evaluating durability, it is possible to determine whether a concrete pole that has been installed for approximately 65 years can continue to be used because it has not been subjected to any load that could cause damage, or whether it needs to be replaced early due to the load that could cause damage.The present invention is based on this knowledge.

[0022] [First embodiment] 1 is a schematic diagram showing a first embodiment of an evaluation system of the present invention. The evaluation system 101 is a system for evaluating the durability of a concrete pole 1. The evaluation system 101 has measurement means 201 and 202 with probes in contact with the concrete pole 1, and a processing unit 301 for processing the measurement results.

[0023] [Evaluation method flow] Fig. 2 is a flow diagram showing an example of the evaluation method of the present invention. The evaluation method of the present invention is a method for evaluating the durability of a concrete pole, and can be carried out, for example, as follows, as shown in the flow diagram of Fig. 2. Step S11 is a process of measuring the ultrasonic wave propagation characteristics of the concrete pole. Step S21 is a step of calculating durability based on the propagation characteristics of ultrasonic waves. Step S31 is a process of displaying the calculated durability of the concrete pole.

[0024] [Concrete Pole 1] The present invention is directed to evaluating the durability of concrete poles such as utility poles. Concrete poles are used for power distribution poles, telephone communication poles, mobile and wireless base stations, railway poles, lighting poles, ball protection nets, sand protection nets, disaster prevention radio systems, and design poles. More specifically, concrete poles include utility poles and power poles for power transmission and distribution, utility poles, telephone poles, and telegraph poles for communications, and overhead line poles for electric railways. The present invention is particularly applicable to prestressed concrete utility poles.

[0025] There are various types of concrete poles depending on the installation location and purpose, and several types of standardized utility poles are manufactured and sold by concrete pole manufacturers, etc. The present invention can target various types of concrete poles by using the durability judgment range, etc. of the concrete pole to be evaluated and a concrete pole of the same type as the reference concrete pole.

[0026] The propagation characteristics are analyzed by propagation characteristic analysis means 321 to obtain values ​​for calculating durability based on information acquired by measurement means 201 and 202 via wired or wireless means and then converted into values ​​for calculating durability based on the information. Durability calculation means 322 calculates durability based on the analysis results.

[0027] [Measurement means 201, 202] The measuring means 201 and 202 are used to measure the propagation characteristics of ultrasonic waves in a concrete pole. The measuring means 201 and 202 are used by appropriately attaching the devices to the concrete pole so that the probes come into contact with the pole.

[0028] [Durability calculation means 322] The durability calculation means 322 is a part that calculates the durability of the concrete pole based on the propagation characteristics of ultrasonic waves and collating it with the durability criteria.

[0029] [Ultrasound] Ultrasonic waves are elastic vibration waves with high vibration frequencies. The frequency of the ultrasonic waves can be as low as 20 kHz or higher, and as high as 10 GHz or 8 GHz. Preferably, ultrasonic waves with frequencies of 20 kHz to 500 kHz or 30 kHz to 300 kHz can be used. For example, in the examples described below, ultrasonic waves with a vibrator frequency of 50 kHz are used.

[0030] The measurement means for the ultrasonic propagation characteristics can be a two-probe method. This measurement means is an inspection device incorporating a transmitting vibrator and a receiving vibrator. The probe can convert electric pulses into sound waves and vice versa.

[0031] [Propagation characteristics] As the propagation characteristics of the ultrasonic waves, a velocity index such as the propagation speed of the ultrasonic waves between the two probes or the propagation time when the two probes are arranged at a predetermined length can be used.

[0032] For example, in the example of measuring the propagation velocity shown in Figure 5 in the example described below, a propagation velocity of approximately 5300 m / sec was measured during the manufacture of a concrete pole. The following changes in the propagation velocity were observed when this concrete pole was repeatedly loaded so that it broke after approximately 70 loads. While there was some variation, a propagation velocity of approximately 5200 to 5400 m / sec was observed when the number of loads was small. The propagation velocity decreased around the location where damage began to occur, and by the time of fracture, it began to fall below 4600 m / sec after approximately 50 loads, and by the 70th load, it had fallen to approximately 4200 m / sec.

[0033] For such concrete poles, durability standards can be set based on the standard velocity of sound at the time of manufacture. For example, regarding changes in velocity of sound, indicators can be set such as a decrease in velocity from the standard velocity at the time of manufacture (standard velocity - velocity at time of measurement / standard velocity * 100) of less than 10% (first indicator), 10% or less (second indicator), 15% or less (third indicator), or 20% or less (fourth indicator), and the following durability can be set. First indicator (less than 10%): No abnormalities Second indicator (10% or more): durability is declining Third indicator (15% or more): Significant decline in durability Fourth indicator (20% or more): Extremely high probability of destruction

[0034] Prestressed concrete, which is commonly used in concrete poles, is dense, so even if damage accumulates, cracks and other cavities are small, and even if cracks do occur, it is not clear whether the concrete will break. For this reason, even when tests are conducted under fairly large loads, the change in the initial propagation velocity is small, making it difficult to distinguish from variations due to error, etc. However, as discovered in this invention, a decrease in propagation velocity has been confirmed before actual failure. However, this gradual decrease in propagation velocity accompanying failure is thought to be caused by effects such as pop-out and spalling, but the exact mechanism remains unclear.

[0035] [Probe contact position] It is preferable that the ultrasonic measurement means contacts probes at multiple measurement positions in the height direction and / or circumferential direction of the concrete pole. Here, the height direction / circumferential direction refers to the direction in which the ultrasonic propagation characteristics are evaluated. In the case of the two-probe method, the direction of the transmitting transducer and the receiving transducer is the direction in which they are installed relative to the concrete pole. In Figure 1, it is a schematic diagram in which the measurement means 201 is installed in the height direction along the axial direction during normal use, and the measurement means 202 is installed in the circumferential direction.

[0036] It is preferable to provide one or more measuring means to measure propagation characteristics in the height direction, and more preferably two or more, or three or more. Concrete poles often break at the locations where large bending stress occurs. Since it is sometimes unclear where a concrete pole will break depending on the installation environment, etc., it is possible to measure multiple locations and evaluate based on the location where the propagation characteristics change the most.

[0037] Since the concrete pole is hollow, when the measuring means is arranged in the circumferential direction, it is preferable to arrange it so that the position where the transmitting vibrator and the receiving vibrator are linearly connected does not include any hollow part.

[0038] Although it depends on the size of the concrete pole, the distance between the transmitting vibrator and the receiving vibrator is preferably about several centimeters to several tens of centimeters, more specifically about 10 to 30 cm or 15 to 25 cm.

[0039] [Probe contact position] The predetermined position where the probe makes contact is a long concrete pole that stands upright on the ground. Therefore, the stress received varies depending on the height position of the concrete pole, and the amount of change in the propagation characteristics fluctuates.

[0040] The specific position where the probe of the measurement means is to be brought into contact is preferably set within a range of approximately 2 m above ground level, taking into consideration convenience and the stress state. If the detection position is too high, it will be too far from the fixed ground, making it difficult to detect the fracture origin and making it impossible to detect changes in propagation velocity. In addition, it is necessary to use a special jig or climb a concrete pole to bring the probe into contact. For this reason, it is preferable to detect at a height close to the fracture origin, where changes in propagation velocity are likely to occur and where a person can easily make contact with the probe.

[0041] [Standard concrete pole] Concrete poles, such as utility poles, are generally manufactured, sold, and used in multiple standardized forms within each company. Therefore, when performing the evaluation method of the present invention, a cyclic loading test is performed on a concrete pole of the same type as the concrete pole to be evaluated, and the time history changes in the ultrasonic propagation characteristics associated with the cyclic loading test are obtained. Then, basic test data are obtained by analyzing the ultrasonic propagation characteristics. The concrete pole used to obtain this basic test data is called the reference concrete pole. The durability evaluation criteria can be based on the changes in the ultrasonic propagation characteristics obtained by repeatedly loading the reference concrete pole from the time of manufacture to the time of failure. Since the durability of a concrete pole is designed to last for decades or more depending on the storage and usage environment, the term "as of manufacture" refers to a concrete pole that is in a sound state that can be determined to be substantially free of deterioration. A concrete pole that has not been stored or used in harsh conditions within approximately one year of the date of manufacture can be considered to be in good condition.

[0042] The inventors prepared dedicated equipment capable of performing bending tests in which concrete poles are repeatedly loaded with loads such as twice the crack test load, and conducted repeated loading tests on the concrete poles (see Figure 3). Each concrete pole is designed to break at a load twice the crack test load. Even when twice the crack test load is applied, the concrete poles do not immediately break, but undergo fatigue failure after several hundred loads. To evaluate the concrete poles, a bending test was conducted in which twice the crack test load was repeatedly applied to the concrete poles. Then, the ultrasonic propagation characteristics were evaluated for the concrete poles in which damage had accumulated after the bending test.

[0043] The names of the loads used to evaluate concrete poles such as utility poles are as follows: The "cracking test load" is commonly called the "design load" and is represented by the letter "P." The "elastic load" is the load at which cracks begin to appear and is represented by the symbol "approximately 2 / 4P." The "fracture load" is at least twice the crack test load P. The load at which it actually breaks is approximately 2.3P. This is because there is variation in the strength of concrete and rebar, and a safety factor is taken into account for the materials.

[0044] Processing unit 301 can be executed as application software or the like including a program for performing these processes on various electronic computers having memory, such as a personal computer, tablet terminal, or smartphone. Furthermore, if the electronic computer or the like using display unit 5 for processing unit 301 is an integrated one having a monitor, the display unit may be displayed on that display unit. Furthermore, if the electronic computer or the like has a sensor that can detect the propagation characteristics of ultrasonic waves, measuring means 201, 202, etc. may also be integrated.

[0045] [Durability] As described above, the evaluation system of the present invention can evaluate the durability of a concrete pole. This durability can be evaluated, for example, by evaluating the equivalent of the survivable repeated test load. Concrete poles accumulate damage each time a load equivalent to a design load is applied, and break when the load exceeds the allowable range. On the other hand, if large loads are not applied, they can be used stably upright for a long period of time. Examples of events equivalent to cracking test loads include natural disasters such as typhoons, earthquakes, frost damage, and snowfall, as well as accidents such as automobile collisions. The remaining tolerable expected strength of the concrete pole is evaluated as its durability. Note that these large loads are likely to occur at regular intervals to some extent, so taking these into account can serve as an indicator that can serve as a standard for determining the service life. Furthermore, even if a concrete pole meets specified standards, there may be variations in its actual performance. Evaluating durability before shipping can help determine the level of variation.

[0046] The results of this durability assessment can be output as, for example, "There is a high possibility of destruction if the structure is subjected to n earthquakes of a specified seismic intensity Na or a typhoon of a specified wind speed Nb (m / s) for n hours," or "There is a quality abnormality" or "There is no quality abnormality."

[0047] In connection with the present invention, the following programs can be created and used. This is a program that automatically calculates the experimental values ​​of ultrasonic propagation velocity from the time of manufacture (when the structure is healthy) to the time of destruction, or the rate of decrease in ultrasonic propagation velocity.

[0048] Prestressed concrete is a composite material made of steel bars and concrete. In this composite material, the materials, quality, and scale of the steel bars and concrete vary depending on the structure's intended use and load, and the ratio of their use also varies. Therefore, the failure (deterioration) of the composite material cannot be expressed in general terms with values ​​for "stress," "strain," and "residual strain."

[0049] Composite members are inherently large in scale, making bending tests difficult. In addition, it is common for people not to go to the trouble of destroying the members that have already been constructed to check the relationship between "stress," "strain," and "residual strain." For this reason, prestressed concrete such as concrete poles has a more complex structure than reinforced concrete, making it difficult to evaluate the relationship between "stress," "strain," and "residual strain" and the progression of failure (deterioration) of the member. In addition, to understand the relationship between "stress," "strain," and "residual strain" of concrete poles, bending tests must be conducted, but specialized equipment is required. Until now, there has been no thought of evaluating the progression of failure (deterioration) and replacing them, so there has been no opportunity to evaluate them.

[0050] Depending on the region, concrete poles may be installed with high design strength and toughness. For this reason, it may not be appropriate to uniformly apply standards such as installation period. Therefore, appropriate, quantitatively explainable replacement criteria are also important. This invention can evaluate the installed concrete poles themselves simply by measuring the ultrasonic propagation characteristics, which is a so-called destructive test that can contribute to quantitative evaluation.

[0051] General electricity transmission and distribution utilities are also required to develop appropriate and rational equipment maintenance plans. Equipment maintenance plans require that the replacement of distribution poles be calculated based on the "risk amount," which is the product of the "probability of failure" and the "impact of failure." One method of calculating the "probability of failure" is to multiply the standard expected lifespan of a distribution pole by 65 years by various coefficients. Without an appropriate indicator, the coefficient may have to be set at approximately 1. However, the evaluation method of this invention makes it possible to grasp the damage status of each utility pole, which can also contribute to the setting of such coefficients.

[0052] In Japan, there are approximately 12 million concrete poles for communications and approximately 24 million for power generation. If the calculations were simply based on the period since installation, many of them would need to be replaced at the same time, which may not be realistic. However, if the evaluation of this invention is carried out, appropriate management can be achieved. [Example]

[0053] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not changed.

[0054] [Concrete pole] The test was conducted using Kyushu High Pressure Concrete's "13-19-7" concrete pole, with a length of 13m, a tip diameter of 19cm, and a prestressed concrete design load of 7kN.

[0055] [Standard concrete pole] New pillars: Brand new concrete poles manufactured within the last month were used as new pillars.

[0056] [Measurement means] Ultrasonic testing equipment: Marui "UST" (Ultra Sonic Tester: P-wave transducer with a frequency of 50 kHz, two-probe method)

[0057] [Contact position of measuring means] Figure 4 shows an image of the position where the probe of the ultrasonic testing machine used as the measuring means was brought into contact. The probe was placed in contact with multiple locations according to the state of the concrete pole during the bending test, as shown below. The concrete pole was bent toward the front of Figure 4. Ultrasonic (1) Tensile direction in the vertical direction (in Figure 4, "tensile" is written on the back side of the utility pole) Ultrasonic (2) Upper part of the compression side in the height direction (referred to as "upper compression" because it is the upper side in Figure 4) Ultrasonic (3) Lower part of the compression side in the height direction (referred to as "under compression" because it is the lower part in Figure 4) Ultrasonic (4) Circumferential compression side (referred to as the circumferential direction on the right side of the fixed utility pole in Figure 4)

[0058] At the positions where the probes were in contact, the distance between the two probes was approximately 40 cm for (1) to (3), and approximately 26.7 cm (1 / 4 of the circumference of the utility pole) for (4).

[0059] Distortion Strain gauge: Tokyo Measuring Instruments strain gauge P series (polyester strain gauge) "PL-60-11" was used. Strains (1) to (4) were measured to measure the circumferential strain on the compression side of the utility pole, with measurement position (4) approximately 1,890 mm from the bottom end of the axial direction (height direction) of the utility pole, and strain gauges were placed at measurement positions (3) to (1) approximately every 2,160 mm from measurement position (4). In other words, they were placed at predetermined intervals from the top when erected, so that positions (1) to (4) were placed at predetermined intervals. Using the utility pole in Figure 4 as an example, these measurement positions are on the left side of Figure 4 and are outside the image due to the pole's long length. Strain measurements at ground level (1) to (4) were taken to measure the circumferential strain on the compression side of the pole, selectively measuring the vicinity of the ground level in the axial direction (height direction) of the pole. From the right side of Figure 4, they are ground level (4), ground level (3), ground level (2), and ground level (1) (outside the image).

[0060] [Bending test] A bending test was conducted on a concrete pole. Figure 3 shows an image of the concrete pole in its bent state. The bending test load was 2P, and the specimen was bent in one direction, then released and returned to its original position, which constituted one cycle (one time). After each cycle, the ultrasonic propagation characteristics were measured in the released state using an ultrasonic testing machine with a measuring means at each contact position. In addition, strain was measured using a strain measuring device with a probe in contact with the ground in the circumferential direction.

[0061] Fig. 5 is a graph showing the measurement results of the propagation characteristics of ultrasonic waves during a bending test of a concrete pole, and Fig. 6 is a graph showing the strain during a bending test of a concrete pole.

[0062] At contact position (1) and elsewhere, a decrease in ultrasonic propagation velocity was observed as the number of bending tests increased. Up to around 10 times, the change in propagation velocity was small. A decrease began to be observed from 10 times or more, and the decrease in propagation velocity became more pronounced as the number of bending tests increased to 30, 40, and so on. In this bending test, the column broke after 60 bending tests. In particular, a significant decrease in ultrasonic propagation velocity was observed at contact position (4), in the "circumferential direction of compression." It was also confirmed that circumferential strain was occurring in conjunction with the decrease in ultrasonic propagation velocity. Note that the strain values ​​were obtained in this test because the probe was in contact before the bending test, and it is difficult to determine the strain on a column in service over time.

[0063] For this reason, when this concrete pole is used as a reference concrete pole, it is possible to set example criteria based on propagation speed, such as those in Table 1 below. This standard is also useful as an evaluation standard for the durability of in-service poles, where the actual load varies depending on various external factors such as installation location and climate.

[0064] [Table 1] [Industrial Applicability]

[0065] The present invention can be used to evaluate the durability of concrete poles and is therefore industrially useful. [Explanation of symbols]

[0066] 1 concrete pole 101, 102 Rating System 201, 202 Measurement means 3 Processing section 31 Input Method 301, 302 Control means 321 Analysis means 322 Durability calculation method 33 Storage section 34 Output section 5 Display section

Claims

1. a step of measuring the propagation characteristics of ultrasonic waves in the concrete pole by a measuring means for measuring the propagation characteristics of ultrasonic waves by bringing a probe into contact with the concrete pole; A method for evaluating the durability of a concrete pole, comprising a step of calculating the durability of the concrete pole by comparing the propagation characteristics with an evaluation criterion for the durability of the concrete pole.

2. The method according to claim 1, wherein the durability evaluation criteria are based on ultrasonic propagation characteristics obtained by repeatedly loading a reference concrete pole from the time of manufacture to the time of failure.

3. 3. The method according to claim 1 or 2, wherein the measuring step involves bringing a probe of the ultrasonic measuring means into contact with a plurality of measurement positions in the height direction and / or circumferential direction of the concrete pole to measure.

4. a measuring means for bringing a probe into contact with a concrete pole to measure the propagation characteristics of ultrasonic waves in the concrete pole; A system for evaluating the durability of a concrete pole, comprising: a calculation means for calculating the durability of the concrete pole by comparing the propagation characteristics with an evaluation standard for the durability of the concrete pole.

5. This is a program for evaluating the durability of concrete poles. A program for causing a computer to function as a calculation means for calculating the durability of a concrete pole by comparing the propagation characteristics of ultrasonic waves in the concrete pole, obtained using a measurement means for measuring the propagation characteristics of ultrasonic waves by contacting a probe with the concrete pole, with an evaluation standard for the durability of the concrete pole.

Images