Abstract
In the impact-echo method, the presence and the locations of defects in concrete are estimated by identifying peak frequencies in the frequency spectra. In practical applications, however, spectra obtained include so many peak frequencies that it is very difficult to identify particular defects. In this concern, SIBIE (Stack Imaging of spectral amplitudes Based on Impact Echo) is developed as an imaging technique applied to the impact-echo. In this study, the SIBIE procedure is applied to identify ungrouted post-tensioning ducts in prestressed concrete.
An applicability of the procedure to identify ungrouted tendon ducts in post-tensioned concrete girders was examined in the both cases of polyethylene and steel (tin-galvanized) sheaths. Results show a great promise for inspecting imperfectly-grouted ducts in prestressed concrete bridges.
