| 摘要 |
PROBLEM TO BE SOLVED: To measure strain of a PC material at an arbitrary position or over the entire length thereof by arranging an optical fiber to be interlocked with the movement of the PC material and detecting strain of the PC material based on the measurement of strain of the optical fiber. SOLUTION: For example, a PC material 1 with strain detection is arranged in concrete 8 and an optical fiber 3 extending from one end of the PC material 1 is fixed with a strain detector 10. The PC material 1 with strain detection is inserted into the concrete 8 through a sheath 9 and stretched by means of a stretching jack 11, for example. The strain detector 10 delivers incident light to the optical fiber 3 and receives reflected light therefrom and determines strain distribution of the optical fiber 3 based on the incident light and reflected light. Frequency of Brillouin scattering light is shifted depending on the state of strain of the optical fiber 3. Consequently, state of strain of the optical fiber 3 can be measured based on the frequency shift and strain of the optical fiber 3 can be located based on the time lag after delivering incident light before receiving reflected light.
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