| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for measuring a tension of an embedded rod member, which is realized by using a simple technique, readily measures the natural frequency and can estimate the tension, without having to make the vibrating string length of the existing rod in an embedded state exposed, even if the numerical value of the vibrating string length is unknown. SOLUTION: The method for measuring the tension of the embedded rod member, which is a method for measuring the tension from a limited exposure length, without exposing the vibrating string length of an existing embedded rod member, even when the vibrating string length is unknown, comprises exposing a portion which is a vibratable length part in the vibrating string length of the rod member which is an object to be measured, by using a drilling means, a chipping means and the like; disposing a vibration sensor at the exposed portion; striking and vibrating the exposed portion by using a striking means, such as a hammer, and obtaining the natural frequency (f<SB>i</SB>) from the vibration detected by the vibration sensor; obtaining an apparent vibrating string length (L) of the rod member, from the relation between the natural frequency (f<SB>i</SB>) and the order of the vibration mode (i); and obtaining the tension (T). COPYRIGHT: (C)2008,JPO&INPIT
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