| 講演要旨(和文) | | 地震で建築物は損傷を受けるが、壁面内部の損傷度を目視で判断することは難しい。本研究では壁面内部の損傷を計測する手段として、地上設置型合成開口レーダ(Ground-Based Synthetic Aperture Radar:GB-SAR)を用いた非破壊検査を用いる。本研究の目的はコンクリート試供体内部に格子状に配置された鉄筋を計測することである。実験は2次元計測で行い、計測器にはベクトルネットワークアナライザ(Vector Network Analyzer:VNA)を、アンテナにはスパイラルアンテナを用いて3偏波で計測を行った。また円偏波基底から直線偏波基底へ変換処理を行いHH、VV、HVのレーダイメージを得た。円偏波基底では鉄筋は縦横両方とも観察することができるが、HHでは横方向、VVでは縦方向の鉄筋のみを観察でき、直線偏波基底では一方向の鉄筋を計測することが可能であることが分かった。 |
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| | 講演要旨(英文) | | Natural disasters such as earthquakes often occur in Japan. Houses and buildings are damaged due to earthquakes. It is difficult to know how much damage is caused inside a wall only by a visual observation. GB-SAR (Ground-Based Synthetic Aperture Radar) measurement is a way to measure the inside of a wall as a non destructive inspection. By using GB-SAR, it can measure the inside without contacting a wall. In this study, imaging latticed rebars and damages inside a wall is an objective. For the study, a polarimetric radar system was built based on a vector network analyzer (VNA). Spiral antennas were used to achieve a wide frequency bandwidth. We carried out measurements with 2-dimentional scan. The scanning was repeated three times with different combinations of polarization, i.e., LL, RR, and LR. These radar data could image all the rebars. The measured data in the circular polarization basis are transformed to the linear polarization, i.e., HH, VV and HV. The obtained radar image in the HH polarization shows an only horizontally placed rebars and VV shows only vertical one. |
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