TY - GEN A1 - Wiggenhauser, Herbert A1 - Krause, Martin A1 - Krieger, J. ED - Medlock, R. T1 - Tests and assessments of NDT methods for concrete bridges T2 - Structural materials technology III N2 - A research project is described involving a comparison of different non-destructive test methods for concrete bridges. A cooperative test series was started with the aim to compare and evaluate the performance and benefits of the latest technical developments in this field. For this purpose test specimens with localized defects were produced. Different modifications of radar, ultrasonic-echo and impact-echo methods were investigated. Including two- and three- dimensional reconstruction models. The experiments were accompanied by numerical simulation of the propagation of sound waves and microwaves. The results showed that the radar and the ultrasonic methods were efficient tools to locate the tendon ducts accurately if the reinforcing bars were not to narrowly spaced. The ultrasonic imaging methods were capable of identifying injection and compaction faults in a blind test. The good performance of the impact-echo method with regard to locating tendon ducts which was claimed in several publications could not be validated in the present investigations. The simulation models provided valuable information on how to improve the experimental test program and its evaluation. T2 - Structural materials technology III CY - San Antonio, TX, USA DA - 1998-03-31 KW - Non-destructive testing in civil engineering KW - concrete bridges KW - tendons KW - ducts KW - injection faults KW - compaction faults KW - round robin test KW - ultrasonic testing KW - pulse radar KW - impact-echo KW - reconstruction calculation KW - synthetic aperture focusing technique (SAFT) KW - magnetic stray field KW - ruptures in prestressing reinforcement PY - 1999 SN - 0-8194-2849-3 DO - https://doi.org/10.1117/12.300098 N1 - Serientitel: SPIE proceedings series – Series title: SPIE proceedings series VL - 3400 SP - 258 EP - 269 PB - SPIE CY - Bellingham, Wash. AN - OPUS4-829 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -