JP6723540B2 - Excitation device, vibration measuring system, vibration measuring method, and tension measuring method - Google Patents

Description

The present invention relates to a device for vibrating a diagonal member used in a cable-stayed bridge, a vibration measuring system including the device, a vibration measuring method, and a tension measuring method.

One type of bridge is a cable-stayed bridge in which the tower and bridge girders are diagonally connected by cable (cable) and supported. This cable-stayed bridge supports bridge girders through which people, vehicles, etc. pass by the tension of the cable, and in the management of its construction, the appearance inspection and tension measurement of the cable are carried out.

A so-called vibration method is generally used for measuring the tension of a cable, in which the natural frequency and the damping constant of the cable are measured and the tension is obtained based on the measurement result. The frequency is obtained by forcibly applying vibration to the cable, measuring the vibration waveform with a vibration measuring device such as an accelerometer, and performing Fourier analysis.The tension is calculated from the frequency by a known formula. I am asking for.

Conventionally, the rope is tied up with an aerial work vehicle, and a few workers pull the rope to give forced vibration to the cable, but this requires a large number of personnel and aerial work vehicles. A wide work area must be secured to install an aerial work vehicle.

Therefore, there has been proposed a device that does not require a work platform for aerial work and saves manpower while applying vibration to a cable and performing a performance test or the like of a cable vibration damping device (see, for example, Patent Document 1). ).

JP, 10-118964, A

However, the device described in Patent Document 1 has a problem in that it cannot be vibrated in a specific direction unless two rotary vibration generators are installed, and thus cannot be provided at a low cost.

Further, in order to measure the vibration, a vibration measuring device can be attached to the device described in Patent Document 1, but since the vibration generated by the vibration generating means is directly measured, the vibration of the cable can be accurately measured. There was also the problem that it could not be measured.

Therefore, it has been desired to provide an apparatus and a system that are efficient, inexpensive, and can accurately measure the vibration of a cable.

In view of the above problems, the present invention is a vibrating device that vibrates a diagonal member (cable) used for a cable-stayed bridge, and includes a frame member having a passage through which the diagonal member passes and provided at both ends of the frame member. And projecting toward the center of the opening continuing to the passage, contacting the upper outer surface of the diagonal member passed through the passage to support the frame member on the diagonal member, and the diagonal member passing through the passage. And a vibration measuring device which is located below the diagonal member of the frame member and which is attached to the frame member, and which can travel in the longitudinal direction of the diagonal member and is pulled by a vibration measuring device for measuring the vibration of the diagonal member. A vibration device is provided.

ADVANTAGE OF THE INVENTION According to this invention, the vibration of a cable can be measured correctly and efficiently.

The figure which showed the structural example of the vibration measurement system. The figure showing the example of composition of a vibrating device. The figure which showed the structural example of the vibration generation means with which a vibrating device is equipped. The figure which showed one structural example of a vibration measuring apparatus. The figure explaining the position which excites and measures vibration. The flowchart which showed the flow of the vibration measurement performed by the vibration measurement system. The flowchart which showed the flow of the process which calculates tension from a measurement result. The figure which showed another structural example of a vibration measuring device. The figure which showed the structural example of the vibration measuring means with which the vibration measuring apparatus shown in FIG. 8 is equipped. The figure which showed another structural example of a vibration measuring device.

FIG. 1 is a diagram showing a configuration example of a vibration measuring system. This vibration measuring system is a system for measuring the vibration of a cable used in a cable-stayed bridge, and is configured to include a vibrating device and a vibration measuring device. In addition to these, the vibration measurement system may include an information processing device that calculates the tension of the cable and the like from the measurement result. Hereinafter, the vibration measurement system will be described as including an information processing device.

The cable-stayed bridge 10 has a foundation built on the bottom of a river or the sea, and a main tower 11 made of steel or reinforced concrete (RC) on the foundation, and a cable 12 stretched diagonally from the main tower 11. It is a bridge with a structure that directly supports the main girder (bridge girder) 13. In general, the number of main towers 11 is often two, but there may be one or three or more. In FIG. 1, only one main tower 11 is shown. A compressive force acts on the main tower 11. The main girder 13 is a portion through which people and vehicles pass.

The cable 12 connects the main tower 11 and the main girder 13 and supports the main girder 13. The cables 12 are stretched to the left and right across the main tower 11 to balance the forces applied to the left and right, and by increasing the number of cables, the force acting on each cable is reduced.

As the cable 12, it is possible to use a PC steel twisted wire composed of a plurality of PC steel wires, the circumference of which is covered with a resin such as polyethylene. The cable 12 is not limited to this, and a PC steel wire may be put in a protective tube made of a resin such as polyethylene, and a space between the wires may be filled with a filling material such as grout.

The vibration device 20 is a device that generates vibration at an arbitrary position in the length direction of the cable 12, applies the generated vibration to the cable 12, and vibrates the cable 12. The vibration may be generated in the cable by the natural wind without providing the vibration device 20, but in the natural wind, the vibration cannot be concentrated on one point of the cable, and thus the vibration waveform has many peaks. Only natural frequencies of higher modes can be obtained. However, by using the vibrating device 20, if vibration is applied to the central position of the cable, the natural frequency of the primary mode, and if vibration is applied to the position of 1/3 of the length of the cable, the natural vibration of the secondary mode is applied. The natural frequency of an arbitrary mode such as a number can be obtained.

The vibration measuring device 21 is capable of traveling in the length direction of the cable 12, and can be moved by pulling the vibrating device 20 and moving it by self-propelled or to a predetermined measurement position. The vibration measuring device 21 includes means such as an accelerometer capable of measuring the vibration of the cable 12, and measures the vibration of the cable 12 generated by the vibrating device 20. The vibration measuring device 21 is fixed to the cable 12 so as not to move during measurement. The vibration measuring device 21 transmits the measurement result to a verification device (not shown) by wire or wirelessly.

The vibration device 20 and the vibration measurement device 21 are connected by a pulling member 22 such as a rope, and the vibration measurement device 21 pulls the vibration device 20 and moves the vibration device 20 to a predetermined position. By the way, when the vibrating device and the vibration measuring device are combined into one device, the vibration measuring device picks up vibration noise, so that it is not possible to accurately measure the vibration. Therefore, in the present invention, the vibrating device 20 and the vibration measuring device 21 are separated and connected by the pulling member 22. In addition to this, such a configuration can prevent the vibration measuring device from slipping down even at a steep slope due to vibration and a failure of the vibration measuring device, thereby improving safety. In order to minimize the effect of vibration, the traction member 22 is preferably made of a material that does not transmit vibration, and for example, a plurality of springs or elastic members such as rubber can be used.

The information processing device 23 is a computer such as a PC, receives the measurement result from the vibration measuring device 21, obtains the tension of the cable 12 from the measurement result, and the tension decreases as compared with the tension when designing. Verify that you are doing. Therefore, the information processing device 23 includes a receiving unit such as a communication I/F and a calculating unit such as a CPU and a memory for calculating the tension and the like. When the cable-stayed bridge 10 is erected, the tension and the like are adjusted so as to satisfy the design value. Therefore, the information processing device 23 determines from the design value whether there is a change, and if so, how much the change has occurred. The worker can judge the presence/absence of the countermeasure according to the presence/absence and the ratio of the variation.

Since the vibration measuring device 21 is a self-propelled or traction type device, it is moved to an arbitrary position in the length direction of the cable 12, stopped and fixed at that position, and thus the vibrating device 20 towed. Gives vibration to an arbitrary position, vibrates the cable 12, and the vibration measuring device 21 can measure the vibration of the cable 12.

The configuration of the vibration device 20 will be described with reference to FIG. The vibration device 20 includes a frame member 30 having a passage through which the cable 12 passes, as shown in FIG. For the frame member 30, for example, a plurality of aluminum square tubes 30a may be used, and the projections fitted into the square tubes 30a may be connected by a three-way joint 30b extending in three directions. The material may be plastic or steel, but the above aluminum is preferable because it is lightweight, has a certain strength, and has corrosion resistance.

The rectangular tube 30a has a substantially rectangular cross section and is hollow inside. The three-way joint 30b is a connecting member for a rectangular tube in which protrusions extend along three mutually perpendicular axes of x-axis, y-axis, and z-axis. For example, the protrusions are slightly tapered toward the tip. By being pushed into the hollow inside of the square tube 30a, the end with a large cross section can be firmly adhered to the inner surface of the square tube 30a to generate a strong fastening force. Since this is an example, the structure is not limited to such a structure as long as a constant fastening force can be obtained.

Further, the frame member 30 cuts, at each end, two facing two of the four rectangular tubes 30a forming the opening through which the cable 12 shown in FIG. It is possible to adopt a structure in which the connection is made by using a two-way joint in which the protruding portion extends. With such a structure, the frame member 30 can be separated into two parts, and the frame member 30 can be attached so that the cable 12 passes through.

Here, an example using the square tube 30a and the three-way joint 30b has been described, but the present invention is not limited to these members, and a configuration using a circular tube and a three-way joint having a cylindrical protruding portion, four sheets It is also possible to use only the rectangular plates and to join them to form a box-like structure having openings at both ends.

The vibrating device 20 is provided at both ends of the frame member 30 as shown in FIG. 2A, and is directed toward the center of an opening continuous to the passage formed in the frame member 30 as shown in FIG. 2B. Supporting means 31 for supporting the frame member 30 on the cable 12 is included, which abuts on the outer surface of the upper side of the cable 12 protruding and passed through the passage. The supporting means 31 may be any one capable of supporting the frame member 30 on the cable 12, and for example, a fulcrum roller can be used. The fulcrum roller is one of the four rectangular tubes 30a forming the openings through which the cables 12 at each end of the frame member 30 pass, from the two rectangular tubes facing the outer surface above the cable 12 toward the outer surface. It can be composed of a supporting member 31a having a hole protruding and having a rotary shaft 31b inserted therethrough, and a roller 31c having a rotary shaft 31b. This is an example, and other configurations may be used.

Two fulcrum rollers are provided at each end of the frame member 30, and the frame member 30 can be supported by being mounted on the upper side of the cable 12 by these four fulcrum rollers. The contact portion of the fulcrum roller with the cable 12 contacts the outer surface of the cable 12 and supports the frame member 30 on the cable 12, so that the adhesion is good and the friction resistance with the outer surface is large. desirable. Therefore, the contact portion can be formed of an elastic member such as natural rubber, isoprene rubber, urethane rubber, or chloroprene rubber.

The vibrating device 20 further includes a vibration generating unit 32 which is located below the cable 12 of the frame member 30 in which the cable 12 is passed through the passage formed in the frame member 30 and which is attached to the frame member 30. The vibration generating means 32 may be any device as long as it can generate vibration. The vibration generating means 32 is located directly below the cable 12, and a pedestal 33 may be provided on the square tube 30a that constitutes the frame member 30 as needed, and the vibration generating means 32 may be installed on the pedestal 33.

Since only the fulcrum roller is in contact with the upper side of the cable 12, since the lower side is not pressed, the fulcrum roller can be rotated in the circumferential direction. It is possible to suppress vibration in the left and right directions and appropriately vibrate the cable 12 in the vertical direction. Further, by attaching the vibration generating means 32 to the lower position of the cable 12, the vibration generating means 32 functions as a weight, and the rotation of the frame member 30 in the circumferential direction of the cable 12 can be suppressed.

Even if vibration is generated in the cable 12 and the frame member 30 rotates in the circumferential direction of the cable 12, the cable 12 can be supported on the cable 12 by the fulcrum roller on the upper side. It is possible to provide two fulcrum rollers or the like, which do not come into contact with, but extend to adjacent positions. This is an example, and rotation in the circumferential direction is allowed, but other configurations and structures may be used as long as they can be supported by the fulcrum roller. Further, the number of fulcrum rollers is not limited to two and may be three or more.

The vibration generating means 32 used in the vibration device 20 will be described with reference to FIG. FIG. 3A is a front view of the vibration generating means 32, and FIG. 3B is a side view. The vibration generating means 32 can include a motor 40, a rotating shaft 41 that is rotated by the motor 40, and a weight 42 that is attached to the rotating shaft 41 with its center of gravity biased. In the example shown in FIG. 3, the weight 42 has two triangular bases with two bottom surfaces, and the rotary shaft 41 is inserted so as to penetrate a position adjacent to one apex deviated from the center of gravity of the triangle. It is fixed to the shaft 41.

The motor 40 converts electric energy supplied from a storage battery or the like into rotation energy and gives the rotation energy to the rotation shaft 41. The rotating shaft 41 rotates in a fixed direction by the applied rotational energy. Therefore, by adjusting the amount of electric energy supplied to the motor 40, the output rotational energy can be adjusted and the rotational speed of the rotating shaft 41 can be changed.

A weight 42 is attached to the rotating shaft 41, and the position of the center of gravity thereof is displaced from the rotating shaft 41. Therefore, the rotation of the rotating shaft 41 pulls the center of gravity in a certain direction, and as a result, vibration occurs. Here, as the vibration generating means 32, the one configured by using the motor 40, the rotating shaft 41, and the weight 42 is illustrated, but any configuration can be used as long as it can generate vibration.

The vibration generating means 32 may include a control circuit having a communication I/F, and instructs the amount of electric energy supplied from the information processing device 23, specifically, the voltage to be applied, and the control circuit causes the motor 40 to operate. The rotation speed can be changed by controlling the voltage to be applied to the specified voltage. The frequency can be changed by changing the number of revolutions. It should be noted that here, the explanation is given assuming that the applied voltage is controlled, but the amount of current supplied may be controlled.

Next, the configuration of the vibration measuring device 21 will be described with reference to FIG. The vibration measuring device 21 can also include the frame member 50 and the supporting means 51, similarly to the vibrating device 20. However, the supporting means 51 is provided not only on the upper side of the cable 12 but also on the lower side thereof, and is configured so as to be in contact with the cable 12 from four sides in the circumferential direction and to be fixed to the cable 12 so as not to move. .. This is because the vibration of the cable 12 cannot be measured with high accuracy. Further, the support means 51 includes a motor 52 that rotationally drives the fulcrum roller, functions as a travel support means, and can be automatically traveled by the motor 52.

Further, the vibration measuring device 21 is separable into two, like the vibrating device 20, and can be attached so that the cable 12 passes through the inside of the frame member 50.

The vibration measuring device 21 includes a vibration measuring unit 53, and an accelerometer can be used as the vibration measuring unit 53. As the accelerometer, any of a piezoelectric type, an electrokinetic type, a strain gauge type, and a semiconductor type accelerometer can be used. The vibration measuring means 53 is not limited to an accelerometer, and a speedometer for measuring speed or a displacement meter for measuring displacement may be used. When an accelerometer is used as the vibration measuring means 53, a waveform of acceleration when the cable 12 vibrates vertically is obtained as a measurement result. The vibration measuring device 21 includes a control circuit including a communication I/F, and the control circuit can transmit the measurement result to the information processing device 23 using the communication I/F. In addition, the control circuit can receive an instruction from the information processing device 23 to the motor 52 and can perform control to start or stop the motor 52 and change the rotation speed.

The position where vibration is applied and vibration is measured will be described with reference to FIG. In order to measure the natural frequency from the primary mode to the sixth mode for one cable 12, in the primary mode, at the central position A of the cable 12 shown in FIG. 5A, and in the secondary mode, as shown in FIG. It is possible to measure the vibration of the cable 12 by arranging a vibration measuring system at positions B and C when the cable 12 shown in b) is evenly divided into three parts to generate vibration and vibrate the cable 12. it can. Since the positions to be vibrated are the positions A to C, the vibrating device 20 can be arranged at the positions A to C.

Even in the nth-order mode of the third order or higher, similarly, the vibration measuring system can be arranged at each position when the cable 12 is evenly divided into n+1 to generate vibration and measure the vibration of the cable 12. .. In the high-order mode, since the vibration is small, if the position where the vibration is applied and the position where the vibration is measured are close to each other, it is easily affected by noise. For this reason, it is possible to change the length of the pulling member 22 that connects the vibrating device 20 and the vibration measuring device 21 and arrange each at the position of the vibration node to perform vibration and vibration measurement.

The information processing device 23 receives an acceleration waveform as a measurement result, but this acceleration waveform is a complicated waveform. This complicated waveform can be decomposed into monotonous sine waves having different frequencies, the frequency included in each frequency can be evaluated, and the highest peak frequency can be extracted as the natural frequency of the cable 12. A fast Fourier transform FFT can be used to obtain this natural frequency.

The tension of the cable 12 can be calculated from the obtained natural frequency by using a known practical calculation formula or curve fitting method. For details of the practical calculation formula, Hiroshi Sugai, Tohru Shinie, Yoshihiro Hamasaki, “Correction of practical calculation formula for cable tension by vibration method”, Proceedings of JSCE No.525/I-33, pp.351-354, 1995.10 Please refer to. For details of the curve fitting method, Ichiro Yamagiwa, Hideo Utsuno, Kenichi Sugii, Yuji Honda, "Simultaneous estimation method of cable tension and bending stiffness", Kobe Steel Technical Report/Vol.49, No.2, pp.12-15 , 1999.9.

For example, the curve fitting method will be briefly described. When the equation of motion regarding the bending of a one-dimensional member such as the cable 12 on which an axial force acts is expanded into a frequency equation based on boundary conditions and solved, the following relational expression is obtained. Can be obtained.

The above expression 1 is a relational expression when the fixing structure of the cable 12 is a boundary condition where both ends are simply supported, and the above expression 2 is a relational expression when the both ends are completely fixed. In the above formulas 1 to 3, T is the tension of the cable 12 (kN), EI is the bending rigidity of the cable 12 (kN·m ² ), f _n is the nth natural frequency (Hz), and n is the mode order. Represents. Further, ρ is the density of the cable 12 (kg/m ³ ), A is the cross-sectional area of the cable 12 (m ² ), L is the length of the cable 12 (m), and ω is the angular natural frequency (rad/s). Represent

Regarding the relationship between the natural frequency calculated by the fast Fourier transform FFT and the order of the measured mode, it is possible to smoothly connect the calculated points to obtain an approximate curve. The method of obtaining this approximate curve is called curve fitting. By this curve fitting, it is possible to calculate the coefficients of the bending stiffness term and the tension term of the above equations 1 and 2, and the tension T and the bending stiffness EI can be calculated from the coefficients.

However, when the boundary condition is fixed at both ends, as shown in the above expression 2, since the term of φ/π that is a function of the bending rigidity EI and the tension T is included, it is necessary to perform the convergence calculation.

As described above, the tension T and the bending rigidity EI are calculated and compared with the initial values to determine whether there is a change, and if there is a change, how much the change can be obtained. Then, it is possible to determine the presence/absence of countermeasures according to the variation amount.

A flow of vibration measurement of the cable 12 using the vibration measurement system shown in FIG. 1 will be described with reference to FIG. 6, and a process flow of calculating tension from the measurement result will be described with reference to FIG. 7. The vibration measurement starts from step 600, and in step 605, the vibration measuring device 21 and the vibration device 20 are attached to the cable 12 to be measured, and the vibration measuring device 21 and the vibration device 20 are connected by a pulling member such as a rope. To do. The pulling member is preferably a member that does not directly transmit the vibration of the vibrating device 20 to the vibration measuring device 21 and is easily deformed, or a member having flexibility.

The vibration measuring device 21 and the vibrating device 20 are separable into two, respectively, and by connecting the separated two, the cable 12 is passed through the frame members 30 and 50, and the cable is supported by the supporting means 31 and 51. 12 can be supported.

In step 610, the vibration measuring device 21 is moved in the length direction of the cable 12 and is pulled by the vibration measuring device 21 to move the vibrating device 20 to a predetermined position. When measuring the natural frequency of the primary mode, the vibration device 20 is moved to the central position of the cable 12. The vibration measuring device 21 supports the inclined cable 12 so as not to slip down by sandwiching the circumference of the cable 12 from four sides by a fulcrum roller, rotates the fulcrum roller, and advances the frame member 50 to a desired position. Move to position.

In step 615, the vibration device 20 vibrates the cable 12 to vibrate the cable 12. In step 620, the vibration measuring device 21 measures the vibration of the cable 12, and in step 625, the measurement result is transmitted to the information processing device 23. At step 630, it is determined whether the measurement is to be ended. This is the end of the measurement because only one point is measured in the primary mode. Since it is necessary to measure at two or more points in the second or higher mode, the process returns to step 610 and each device is moved to the next point. Then, it is moved to a point to be measured, and when all the measurements have been made, the operation proceeds to step 635 and the measurement is terminated. In this way, the vibration can be measured in a short time because it can be moved to a plurality of points, vibrated and measured.

The tension calculation process starts from step 700, and in step 705, the measurement result is received and acquired. The measurement result is an acceleration waveform. In step 710, the fast Fourier transform FFT decomposes into a sine wave having several frequencies and amplitudes, and the frequency (peak frequency) that appears as a peak in the spectrum waveform that is expressed as the amplitude with respect to the frequency is extracted as the natural frequency. ..

In step 715, the coefficients of the bending stiffness term and the tension term are calculated by curve fitting of the natural frequency extracted for each dimensional mode. In step 720, the initial values of bending rigidity and tension are calculated using the above equation 1 and the calculated coefficient. Further, in step 725, the initial value of φ is calculated by using the above expression 3.

In step 730, the calculated φ is substituted into the term of (n-φ/π) in the above equation 2, and the bending rigidity and the tension are calculated by curve fitting. In step 735, it is determined whether the bending rigidity and the tension converge. For example, it can be determined whether or not it has converged based on whether or not the amount of change from the previously calculated value has become sufficiently small. Specifically, it is possible to determine whether or not convergence has occurred by providing a threshold value and determining whether or not the change amount is smaller than the threshold value. If it is determined in step 735 that it has not converged, the process returns to step 725, and if it is determined that it has converged, the process proceeds to step 740.

In step 740, the bending rigidity and the tension are identified as the calculated values, and in step 745, it is compared with the design tension or the like to determine whether or not there is a change, the tension is evaluated, and the processing ends in step 750. If there is no change, there is no need to take any special measures such as repairs, because the condition is the same as at the time of installation. On the other hand, if there is a change, the degree of change is calculated. Depending on the amount of fluctuation, it is possible to take measures such as repairing.

The vibration measuring device 21 is not limited to the configuration shown in FIG. 4, and may have a configuration as shown in FIG. 8, for example. FIG. 8A is a side view seen from a direction perpendicular to the length direction of the cable 12, and FIG. 8B is a front view seen toward the length direction of the cable 12. The vibration measuring device 21 includes a frame member 50, a supporting unit 51, a motor 52 that is a driving unit, and a vibration measuring unit 53, as in FIG. In the example shown in FIG. 8, the support means 51 is composed of a first support means 51a and a second support means 51b. The first support means 51a is provided on each of the two ends of the upper frame member 50, four in total, and supports the drive roller 54, the motor 52 for rotating the drive roller 54, the drive roller 54 and the motor 52. And a supporting member 55 that operates.

Two second supporting means 51b are provided, one at each end of the lower frame member 50, and each of the driven rollers 56, a supporting member 57 for supporting the driven roller 56, and a slide movement urging mechanism 58. It consists of The support member 57 is attached to the lower frame member 50 via a slide movement urging mechanism 58.

The slide movement urging mechanism 58 has, for example, a spring as an urging means, and enables the support member 57 to move up and down. Further, the driven roller 56 on the support member 57 is directed toward the upper cable 12. It is possible to support the vibration measuring device 21 on the cable 12 by pressing and pushing it together with the upper drive roller 54. By providing the slide movement urging mechanism 58, it is possible to contribute to the improvement of the ground pressure of the cable 12 and the driving force of the first supporting means 51a.

The vibration measuring means 53 is attached to one supporting member 57 of the two second supporting means 51b, and is provided integrally with the abutting member that abuts the outer surface of the cable 12. The vibration detector and switching means for switching the contact member to the cable 12 between contact and non-contact.

The vibration measuring means 53 will be described in detail with reference to FIG. The vibration measuring unit 53 includes a brake pad 60 as a contact member, a vibration sensor 61 as a vibration detector, a spring 62, a link plate 63, a switching motor 64 as a switching unit, a crank portion 65, and a link. 66 to 68 are included.

When measuring the vibration of the cable 12, the brake pad 60 is a member that contacts the cable 12 and fixes the vibration measuring device 21 so that it does not move. The vibration sensor 61 is a sensor for measuring vibration of an accelerometer or the like, and is attached integrally with the brake pad 60.

The brake pad 60 is attached to the link plate 63 via a spring 62, allows the brake pad 60 to move in the vertical direction, and can also be kept pressed against the cable 12 by the spring 62. The brake pad 60 includes a shaft extending in a direction perpendicular to the length direction of the cable 12, and head portions 60a having expanded diameters at both ends of the shaft, and the shaft has an elongated hole 63a provided in the link plate 63. It is inserted. For this reason, the brake pad 60 is movable in the vertical direction, but is movable, and is also movable in the vertical direction, although slightly.

The link plate 63 is connected to the support member 57 via the links 67 and 68 arranged in parallel, and the links 67 and 68 swing, so that the link plate 63 is parallel to the support member 57, that is, the vertical direction. It is configured to be able to move to. The link 67 is connected to the crank portion 65 attached to the drive shaft of the switching motor 64 via the link 66, and when the switching motor 64 as the switching unit rotates, the link 67 is formed by the crank portion 65 and the link 66. It is configured to swing.

By controlling the rotation of the switching motor 64, the link plate 63 can be moved up and down, and the brake pad 60 integrally attached with the vibration sensor 61 is pressed against the cable 12 shown in FIG. 9B. The contact state can be switched to the state in which the cable 12 is separated from the cable 12 shown in FIG. 9A (non-contact state).

By adopting the configuration in which the brake pad 60 is switched between the contact state and the non-contact state in this way, the brake pad 60 is prevented from coming into contact with the surface of the cable 12 regardless of the diameter of the cable 12. The vibration measuring device 21 can be moved. Further, the brake pad 60 can be pressed against the surface of the cable 12 to reliably fix the vibration measuring device 21 to the cable 12 at the measurement position.

Further, since the brake pad 60 is supported from the link plate 63 via the spring 62 and a gap is provided so as to allow some movement in the vertical direction, the vibration measuring device 21 moves in the circumferential direction of the cable 12. Even if it vibrates, the vibration is not transmitted to the vibration sensor 61 mounted integrally with the brake pad 60. Therefore, accurate vibration measurement with less noise becomes possible.

Further, by pressing the brake pad 60 against the cable 12, the vibration measuring device 21 can be stopped and fixed at that position, so it is not necessary to apply a voltage to the motor 52 to generate torque during measurement, The power consumption can be reduced accordingly.

By using the vibration measuring system in which the vibration measuring device 21 having such a configuration and the vibrating device 20 are combined, it is possible to efficiently investigate the vibration characteristic at an arbitrary position of the cable 12.

The vibration measuring device 21 can include an image pickup unit 70 as shown in FIG. 10 for confirming deterioration and the like of a portion in contact with the brake pad 60. This is because if the brake pad 60 is deteriorated or the surface of the cable 12 is soiled, the brake cannot work and accurate vibration measurement cannot be performed. The image pickup means 70 can be attached to each of the four rectangular tubes 50a arranged in parallel with the cable 12 so as to face the cable 12. Further, the light source 71 may be provided in the vicinity of the image pickup unit 70 together with the image pickup unit 70. It should be noted that the image pickup means 70 and the light source 71 can be used not only for the dirt of the cable 12 but also for the purpose of investigating the deterioration state and the like.

In the example shown in FIG. 10, four image pickup means 70 and four light sources 71 are provided, and a range of approximately 90° in the circumferential direction of the cable 12 is imaged using one image pickup means 70 and one light source 71. Thereby, the entire circumferential direction can be imaged. In addition, in FIG. 10, the two imaging means 70 and the light source 71 are hidden in the rectangular tube 50a.

The entire cable 12 is imaged by taking an image of the entire circumferential direction at an arbitrary position in the length direction of the cable 12, moving the cable 12 by a certain distance, and then taking an image of the entire circumferential direction at the next position. It is possible to investigate the deterioration situation of.

The imaging can be performed by irradiating the surface of the cable 12 with light from the light source 71 and imaging the surface with the imaging unit 70.

A light bulb, a fluorescent lamp, an LED (Light Emitting Diode) light, or the like can be used as the light source 71. The light source 71 is preferably an LED light because of its low power consumption, long life and small size. The light source 71 is indispensable when the frame member 50 is formed by four plates, but in the case where the frame member 50 is formed by using the square tube 30a and the three-way joint 30b, its outer surface is exposed to light from the outside. You can omit it because you can see the state of. However, it is preferable to provide the light source 71 because the brighter one can clearly see the situation.

As the image pickup unit 70, a camera equipped with a CCD (Charge Coupled Device) image sensor using a photodiode or a CMOS (Complementary Metal Oxide Semiconductor) image sensor can be used. The imaging unit 70 can include a storage device for recording the captured image and a control circuit including a communication I/F for transmitting to the verification device by wire or wirelessly.

In FIG. 10, the configuration including the four image pickup units 70 and the four light sources 71 is shown, but the number may be three or less as long as the entire circumferential direction of the cable 12 can be appropriately imaged. It is also possible to provide five or more image pickup means and light sources in order to improve the accuracy of inspection. In addition, by using a rail member or the like so that the imaging means and the light sources can be moved so as to be able to make one rotation in the circumferential direction of the cable 12, the number of the imaging means and the number of the light sources may be only one each. It is possible.

By using the vibration measuring device 21 provided with such an image pickup means 70, the appearance inspection of the cable 12 can be easily performed at the same time as the vibration characteristic inspection, and the work efficiency can be improved. Further, by using the vibrating device 20, it is possible to automatically vibrate at an arbitrary position, so that the number of workers can be reduced. By manipulating the number of rotations of the motor, it is possible to change the cycle of vibration, and it is possible to perform vibration according to each dimensional mode. Further, since it can be moved to an arbitrary position without using an aerial work vehicle, it is not necessary to secure a working space for aerial work personnel and traffic regulation is not required.

So far, the vibrating device, the vibration measuring system and the vibration measuring method of the present invention have been described in detail with reference to the embodiments shown in the drawings, but the present invention is not limited to the above-mentioned embodiments, Other embodiments, additions, changes, deletions and the like can be modified within a range that can be conceived by those skilled in the art, and in any aspect, as long as the action and effect of the present invention are exhibited, the scope of the present invention It is included.

10... Cable-stayed bridge, 11... Main tower, 12... Cable, 13... Main girder, 20... Excitation device, 21... Vibration measuring device, 22... Traction member, 23... Information processing device, 30... Frame member, 30a... Square tube, 30b... Three-way joint, 31... Supporting means, 31a... Supporting member, 31b... Rotating shaft, 31c... Roller, 32... Vibration generating means, 33... Pedestal, 40... Motor, 41... Rotating shaft, 42... Weight , 50... Frame member, 51... Supporting means, 51a... First supporting means, 51b... Second supporting means, 52... Motor, 53... Vibration measuring means, 54... Driving roller, 55... Supporting member, 56... Follower Roller, 57... Support member, 58... Sliding movement urging mechanism, 60... Brake pad, 60a... Head part, 61... Vibration sensor, 62... Spring, 63... Link plate, 63a... Oblong hole, 64... Switching motor, 65 ... crank part, 66 to 68 ... link, 70 ... imaging means, 71 ... light source

Claims (10)

A vibrating device for vibrating a diagonal member used for a cable-stayed bridge,
A frame member having a passage through which the diagonal member passes;
The frame member is supported on the diagonal member by being provided at both ends of the frame member, protruding toward the center of an opening continuous to the passage, and abutting on the outer surface of the upper portion of the diagonal member passed through the passage. Support means for
A vibration generating unit attached to the frame member, the vibration member being located below the diagonal member of the frame member having the diagonal member passed through the passage;
A vibrating device that is runnable in the length direction of the diagonal member and is pulled by a vibration measuring device that measures the vibration of the diagonal member. The supporting means includes a roller that abuts on the diagonal member and a supporting member that rotatably supports the roller and is fixed to the frame member, and at least two supporting members are provided at both ends of the frame member. The vibrating device according to Item 1. 3. The vibration generator according to claim 1, wherein the vibration generating unit includes a rotating shaft, a motor that rotates the rotating shaft in a fixed direction, and a weight that is attached with a center of gravity deviated from the rotating shaft. apparatus. A vibration measuring device according to any one of claims 1 to 3, and a vibration measuring device for pulling the vibrating device and vibrating by the vibrating device to measure vibration of the generated diagonal member. , Vibration measurement system. The vibration measuring device includes a frame member having a passage through which the diagonal member passes, and projecting toward a center of an opening that is provided at both ends of the frame member and continuous with the passage, and the oblique member passing through the passage. A vibrating support unit that contacts the outer surface of the diagonal member to support the frame member on the diagonal member and that can move in the longitudinal direction of the diagonal member, and a vibration measurement for measuring the vibration of the diagonal member. And means
A switch for switching the vibration measuring means so that the contact member comes into contact with the diagonal member, a vibration detector integrally provided with the contact member, and the contact member comes into contact with or separates from the diagonal member. The vibration measurement system according to claim 4, including means. The vibration measuring system according to claim 5, wherein the vibration measuring device includes an image pickup unit which is provided so as to face the diagonal member and which picks up an image of the traveling support unit, the outer surface of the diagonal member, or both. 7. The vibration measuring system according to claim 6, wherein the vibration measuring device includes a light source that is provided in the vicinity of the image capturing unit and emits light to a range captured by the image capturing unit. A receiving unit that receives a measurement result from the vibration measuring device, and a calculation that calculates the vibration frequency of the diagonal member from the measurement result received by the receiving unit, and a tension that acts on the diagonal member from the calculated frequency. The vibration measurement system according to claim 4, further comprising an information processing device including a means. A vibration measuring method for vibrating a diagonal member used for a cable-stayed bridge and measuring the vibration of the diagonal member,
A frame member having a passage through which the diagonal member passes, and an outer surface on the upper side of the diagonal member that is provided at both ends of the frame member and projects toward the center of an opening that is continuous with the passage and that is passed through the passage. Supporting means for supporting the frame member on the diagonal member by contacting with the frame member, and vibration attached to the frame member, which is located below the diagonal member of the frame member through which the diagonal member is passed. A vibrating device including a generating means, and a vibration measuring device capable of traveling in the lengthwise direction of the diagonal member, for measuring the vibration of the diagonal member, being attached to the diagonal member,
Pulling the vibrating device by the vibration measuring device and moving it to a predetermined position in the longitudinal direction of the diagonal member,
Vibrating the diagonal member by the vibrating device,
Measuring the vibration of the diagonal member with the vibration measuring device. A method of exciting a diagonal material used for a cable-stayed bridge, measuring the vibration of the diagonal material, and measuring the tension of the diagonal material from the measurement result,
A frame member having a passage through which the diagonal member passes, and an outer surface on the upper side of the diagonal member that is provided at both ends of the frame member and that projects toward the center of an opening that is continuous with the passage and that is passed through the passage. A support means for contacting the frame member with the diagonal member, and a vibration attached to the frame member, the supporting member being positioned below the diagonal member of the frame member through which the diagonal member is passed. A vibrating device including a generating means, and a vibration measuring device capable of traveling in the lengthwise direction of the diagonal member, for measuring the vibration of the diagonal member;
Pulling the vibrating device by the vibration measuring device and moving it to a predetermined position in the longitudinal direction of the diagonal member,
Vibrating the diagonal member by the vibrating device,
Measuring the vibration of the diagonal member by the vibration measuring device,
Repeating the moving step, the vibrating step and the measuring step, and measuring vibration at a plurality of positions in the length direction of the diagonal member,
Transmitting the measurement results at the plurality of positions from the vibration measuring device to the information processing device,
The information processing apparatus uses the measurement results at the plurality of positions to apply a predetermined function to perform a convergence calculation to calculate the tension of the diagonal member.