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The Scientific World Journal
Volume 2014, Article ID 194295, 14 pages
http://dx.doi.org/10.1155/2014/194295
Research Article

Condition Assessment of PC Tendon Duct Filling by Elastic Wave Velocity Mapping

1Department of Civil Engineering, University of Malaya, Kuala Lumpur, Malaysia
2Department of Civil Engineering, Nihon University, Tokyo, Japan
3Graduate School of Engineering, Kyoto University, Kyoto, Japan

Received 12 November 2013; Accepted 16 December 2013; Published 6 March 2014

Academic Editors: A. Esmaeily, B. Kumar, and A. Rodríguez-Castellanos

Copyright © 2014 Kit Fook Liu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Imaging techniques are high in demand for modern nondestructive evaluation of large-scale concrete structures. The travel-time tomography (TTT) technique, which is based on the principle of mapping the change of propagation velocity of transient elastic waves in a measured object, has found increasing application for assessing in situ concrete structures. The primary aim of this technique is to detect defects that exist in a structure. The TTT technique can offer an effective means for assessing tendon duct filling of prestressed concrete (PC) elements. This study is aimed at clarifying some of the issues pertaining to the reliability of the technique for this purpose, such as sensor arrangement, model, meshing, type of tendon sheath, thickness of sheath, and material type as well as the scale of inhomogeneity. The work involved 2D simulations of wave motions, signal processing to extract travel time of waves, and tomography reconstruction computation for velocity mapping of defect in tendon duct.