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A Fundamental Study of Polarimetric GB‐SAR for Nondestructive Inspection of Internal Damage in Concrete Walls
Author(s) -
TAKAHASHI KAZUNORI,
OKAMURA SAIKA,
SATO MOTOYUKI
Publication year - 2015
Publication title -
electronics and communications in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.131
H-Index - 13
eISSN - 1942-9541
pISSN - 1942-9533
DOI - 10.1002/ecj.11762
Subject(s) - nondestructive testing , polarimetry , visual inspection , synthetic aperture radar , structural engineering , reinforced concrete , damages , geology , computer science , remote sensing , engineering , scattering , optics , physics , quantum mechanics , artificial intelligence , law , political science
SUMMARY Damages on the surfaces of concrete buildings can easily be detected by visual inspection and can be repaired. However, damages inside walls need nondestructive inspection techniques to be detected, located, and identified. There has been a great demand for such techniques particularly after the 3.11 Great East Japan Earthquake. Ground‐based synthetic aperture radar (GB‐SAR) is a technique that can be potentially used for inspection of concrete walls in a nondestructive and noncontacting manner. The paper reports a fundamental experiment with a polarimetric GB‐SAR system to detect internal damage in a concrete specimen caused by horizontal loading simulating earthquakes. The results show that the system does not have enough resolution to visualize individual defects, and that the effect of steel rebars installed inside the concrete is so strong that it masks weak responses. However, polarimetric analysis demonstrated the capability to minimize the effect of rebars by rearranging polarization basis and to extract weak responses. In particular, internal damages could be detected by observing the volume scattering component in this experiment.