JP2002365157A - Testing method for vibration for structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration test method for a building capable of conducting a vibration test easily and conveniently, while reducing labor for equipment installation in the vibration test. SOLUTION: This vibration test method for the building is used for measurement of a vibration characteristic of a structure 1. In the method, an existing facility 2 standing on the inside (periphery) of the structure 1 and capable of generating vibration is driven to measure the vibration characteristic of the structure 1 using the vibration generated by the existing facility 2. Since the existing facility 2 is operated positively for the purpose of the vibration test and since the vibration test is carried out using the vibration generated therein by the existing facility 2, the vibration test is executed easily and conveniently without installing an exciter or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration test method for measuring a vibration characteristic of a structure.

[0002]

2. Description of the Related Art Structures such as buildings and bridges have inherent vibration characteristics, which determine the behavior (response) of structures when subjected to momentarily changing forces such as earthquakes and winds.
For important structures, seismic observations and vibration tests are performed to acquire these vibration characteristics. In addition, it is also possible to judge the deterioration of the structure from the results obtained by the seismic observation and the vibration test.

Conventionally, when investigating the vibration characteristics of a structure, there are mainly two methods other than seismic observation. The first method uses an exciter prepared as a vibration source. An exciter is installed on the rooftop of the building or on the floor inside the building, and a sine wave vibration is forcibly generated horizontally or vertically in the building (structure) to perform the measurement. By controlling the vibration of the exciter, it is possible to perform measurement with a different vibration frequency. By measuring the response of the structure at any point during the excitation, the natural frequency, vibration mode, damping constant, etc. of the structure can be calculated.

[0004] The second method is to use the micro vibration of the structure at all times. Structural structures constantly vibrate due to traffic, wind, waves, etc., and by using this, vibration can be measured without installing an exciter or the like. At the time of vibration measurement, a vibration (seismic) vibration measuring device is placed at an appropriate position in the structure (upper), the micro vibration of the structure is constantly measured, and the measured waveform is analyzed to analyze the vibration characteristics of the structure Can understand.

[0005]

However, in the first method (method using an exciter), it is necessary to secure an installation space for the exciter when performing a vibration test. Often difficult. Before the completion of the structure,
The necessary space is relatively easy to secure and the installation method is not limited in many cases. However, in the case of a structure that is already used, the space and the installation method (such as installation of an anchor on the floor) are also limited. In addition, since the exciter generates vibrations in the structure, it often has a large mass, and equipment in the structure (such as an elevator) cannot transfer the exciter to the upper floor. Sometimes a crane is required.

Second method (method using micro-vibration at all times)
Is usually applied to tall buildings and chimneys with long vibration periods and small attenuation, and is mainly used for measuring small vibrations. In this case, there is a restriction that it is necessary to perform the process at night when avoiding strong winds and is less affected by noise (less noise sources such as traffic and construction). Further, it is often difficult to grasp the higher-order vibration mode corresponding to a higher frequency because the input is small. As described above, the conventional measurement method is not always thorough, and there has been a demand for the development of a vibration test method that can more easily perform a vibration test.

It is an object of the present invention to provide a vibration test method for a structure that enables a vibration test to be performed more easily while reducing the labor required for installing equipment during the vibration test.

[0008]

According to a first aspect of the present invention, there is provided a method for testing a vibration of a structure, which measures a vibration characteristic of the structure. It is characterized in that the equipment is driven and the vibration characteristics of the structure are measured using the vibration generated by the existing equipment.

According to a second aspect of the present invention, in the first aspect of the present invention, the existing equipment is driven in a steady state when the equipment is normal, and generates vibration of a constant frequency. The vibration test is performed by gradually changing the frequency generated by the existing equipment.

According to a third aspect of the present invention, in the second aspect of the present invention, when the existing equipment is inspected, the frequency is gradually reduced when the existing equipment is stopped, and a vibration test is performed at a predetermined measurement point. Then, when restarting the existing equipment, the frequency is gradually increased and a vibration test is performed for another predetermined measurement point.

According to a fourth aspect of the present invention, in accordance with the first aspect of the present invention, the output gain of a seismometer which is permanently installed in the structure is changed, and the vibration during the vibration test is changed. Is detected.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the structure is a power plant building, and the existing facility is installed inside the structure. It is characterized by being a power generation turbine.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a method for testing vibration of a structure according to the present invention will be described. FIG. 1 is a sectional view of a building at the time of a test for performing the vibration test method of the present invention.

The building shown in FIG. 1 is a power generation turbine building 1 in a power plant. A power generation turbine 2 is installed inside the building 1. Normally, the turbine 2 rotates at a high speed to generate power, but because of its heavy weight, it acts as a vibration source and transmits vibration not only to the building 1 but also to the surroundings. The generator unit 3 generates power using the rotation of the turbine 2. Inside the building 1, seismometers (detection units) 4 are installed at several places. These seismometers 4 are permanently installed regardless of the vibration test.

If it is necessary to increase the number of detection units at the time of the vibration test, as shown in FIG. The installed vibration measuring instrument 5 is connected to an existing measuring facility or to a measuring instrument in a measuring vehicle 6 stopped outside the building 1. Note that the existing seismometer 4 may be newly connected to the measuring device in the measuring vehicle 6 or may be measured by the existing equipment as it is (this case will be described in detail later).

Next, the procedure of the vibration test will be described.
In the above-described power generation equipment, the power generation is stopped every predetermined period, that is, the rotation of the turbine 2 is stopped, and the periodic inspection is performed. The vibration test of the present embodiment is performed at the same time as this periodic inspection (some facilities may be required by laws and regulations). Performing the inspection at the same time is convenient because it is not necessary to change the operation schedule of the equipment in operation for the vibration test. Building 1 (Existing equipment:
If the vibration test is always performed together with the inspection of the turbine 2), there is an advantage that it is easy to grasp the temporal change of the vibration characteristic of the building 1.

When the rotation of the turbine 2 is stopped, the turbine 2
Gradually decreases its rotation speed and is finally stopped.
At this time, the frequency of the vibration generated by the turbine 2 also changes from the high frequency side to the low frequency side. This frequency change is convenient because the input vibration frequency is continuously changed during the vibration test. At this time, a vibration test for measuring the vibration response of each part of the building 1 to the vibration generated by the rotation of the turbine 2 is performed.

A generator such as a power plant usually operates at 50 Hz or 6 Hz.
0 Hz AC power is generated, and the main vibration frequency of the vibration generated by the turbine 2 is equal to this. By moving from such a frequency to the lower frequency side, the frequency band when measuring the vibration characteristics of the structure is sufficiently covered, which is convenient. Further, after the end of the periodic inspection, the rotation speed of the turbine 2 is gradually increased to restart the power generation, and finally, the turbine 2 is returned to the previous steady state. At this time, the frequency of the vibration generated by the turbine 2 changes from the low frequency side to the high frequency side.

That is, an opportunity to measure the vibration characteristic again is obtained. Alternatively, the two measurement opportunities can be used for reducing the number of measurement devices without increasing the number of measurements. For example, when there are ten necessary measurement points, five points are measured when the turbine 2 is stopped,
When the rotation of the turbine 2 is restarted, the remaining five locations can be measured. In this way, the number of detectors can be reduced.

As described above, the case where the seismometer 4 already connected is used for detecting the vibration characteristics using the existing seismometer 4 will be briefly described. In these systems, since vibration at the time of an earthquake is measured, it may be optimized for detecting large vibration. In such a case, the vibration at the time of the vibration test may not be sufficiently detected. Therefore, in such a case, it is convenient to increase the output gain with respect to the input to perform the measurement. Such a method may make it possible to further reduce the equipment required for the vibration test using the existing seismometer 4.

Note that the vibration test method of the present invention is not limited to the above embodiment. For example, in the above-described embodiment, the vibration test on the building in which the turbine 2 is installed is performed using the vibration generated by the turbine 2, but the vibration test on the surrounding buildings is performed using the vibration generated by the turbine 2. It is also possible to do. That is, the existing equipment serving as the vibration source does not have to be inside the building to be tested, but may be around the building to be tested.

Further, in the above-described embodiment, the vibration source is a facility which is operated constantly in a normal state. However, the present invention is not limited to this. For example, a large air conditioner or the like may be used as a vibration source. Such an air conditioner generally has a driving load that fluctuates, and is not always operated constantly. Alternatively, it is also possible to use equipment that is not operated during normal operation but is operated only very much, for example, an emergency power generation equipment, as existing equipment serving as a vibration source. Since such an emergency facility is also a facility that is regularly inspected, a test method using the same can enjoy the effect obtained by performing the inspection at the time of inspection as in the above-described embodiment. Further, the vibration test method of the present invention is not limited to the application to the building as described above, but can also be applied to a structure such as a bridge or a chimney.

[0023]

According to the vibration test method of the present invention, the existing equipment is actively operated for the purpose of the vibration test (although it may be performed simultaneously with another purpose [inspection and the like]), and the existing equipment is generated at this time. A vibration test is performed using vibration. For this reason,
ADVANTAGE OF THE INVENTION According to this invention, a vibration test can be easily performed without installing an exciter etc., and the data (recording waveform) required in order to grasp | ascertain the vibration characteristic of a structure can be obtained by this. Since a vibration test does not require installation of a vibration exciter or the like, costs associated with the vibration test can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a building to which a vibration test according to the present invention is applied during a test.

[Explanation of symbols]

1 ... building (structure), 2 ... power generation turbine (existing equipment),
3 ... Generator section, 4 ... (Existing) seismometer, 5 ... Vibration measuring instrument, 6 ... Measurement vehicle.

Claims (5)

[Claims] 1. A vibration test method for measuring a vibration characteristic of a structure, comprising: driving an existing facility which is permanently installed inside or around the structure and capable of generating vibration, and utilizing vibration generated by the existing facility. And measuring the vibration characteristics of the structure by using the method. 2. When the existing equipment is normal, it is driven in a steady state and generates vibration at a constant frequency. By utilizing the equipment inspection time, the frequency generated by the existing equipment is gradually changed. The vibration test method for a structure according to claim 1, wherein a vibration test is performed. 3. When the existing equipment is inspected, the frequency is gradually reduced when the existing equipment is stopped, a vibration test is performed on a predetermined measurement point, and the frequency is gradually increased when the existing equipment is restarted. The vibration test method for a structure according to claim 2, wherein the vibration test is performed on another predetermined measurement point while being raised. 4. The structure according to claim 1, wherein a vibration during a vibration test is detected by changing an output gain of a seismometer permanently installed in the structure. Vibration test method for objects. 5. The structure according to claim 1, wherein the structure is a power plant building, and the existing facility is a power generation turbine installed inside the structure. Vibration test method for structures.