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Evaluation of distributed surface-breaking cracks in concrete using surface wave transmission method
Previous research has indicated that the surface wave transmission (SWT) method can be used to measure the depth of a single surface-breaking crack in concrete. In this paper, the authors extend the SWT method to evaluation of distributed cracks in concrete. The findings from this study are summarized as follows: (1) Amplification coefficient oscillates in the near crack region (near field), while it converges to a constant value in far field for large x/lambda. When the crack spacing is less than two times of the near field size, the forward scattering field caused by the first crack interferes with the backward scattering field caused by the second crack, which causes very complex scattering field between the cracks. (2) Crack spacing affects the surface wave transmission measurement. The transmission coefficient (Tr) shows the lowest value when a/h is between 2 and 3. For large crack spacing, each crack can be treated as a single surface breaking crack, and previous surface wave transmission theories apply. (3) The surface wave transmission decreases with increasing crack number N. For large crack spacing a, the surface wave transmission ratio over N cracks will be (Tr1)N, where Tr1 is the transmission over a single crack. (4) The numerical simulation results provide a guideline for evaluating concrete structures with distributed surface-breaking cracks using the surface transmission method.
Evaluation of distributed surface-breaking cracks in concrete using surface wave transmission method
Previous research has indicated that the surface wave transmission (SWT) method can be used to measure the depth of a single surface-breaking crack in concrete. In this paper, the authors extend the SWT method to evaluation of distributed cracks in concrete. The findings from this study are summarized as follows: (1) Amplification coefficient oscillates in the near crack region (near field), while it converges to a constant value in far field for large x/lambda. When the crack spacing is less than two times of the near field size, the forward scattering field caused by the first crack interferes with the backward scattering field caused by the second crack, which causes very complex scattering field between the cracks. (2) Crack spacing affects the surface wave transmission measurement. The transmission coefficient (Tr) shows the lowest value when a/h is between 2 and 3. For large crack spacing, each crack can be treated as a single surface breaking crack, and previous surface wave transmission theories apply. (3) The surface wave transmission decreases with increasing crack number N. For large crack spacing a, the surface wave transmission ratio over N cracks will be (Tr1)N, where Tr1 is the transmission over a single crack. (4) The numerical simulation results provide a guideline for evaluating concrete structures with distributed surface-breaking cracks using the surface transmission method.
Evaluation of distributed surface-breaking cracks in concrete using surface wave transmission method
Bewertung der Oberflächenrissverteilung in Beton mittels Oberflächen-Transmissionsverfahren
Kee, Seong-Hoon (author) / Zhu, Jinying (author)
2009
7 Seiten, 5 Bilder, 9 Quellen
(nicht paginiert)
Conference paper
Storage medium
English
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