Evaluation of Two New Methods : APEI for inspection of Post-Tensioned Reinforcement and RSIM for Monitoring of Concrete Structures

This report presents the results from the evaluation of two new methods – APEI (Advanced Portable Equipment for Inspection) for in-situ inspection and RSIM (Real-time Structural In-service Monitoring) for in-service monitoring of concrete structures. Both the methods are based on the ultrasonic techniques and were developed in the EU-project “SGIM-2001”. The evaluation results show that the APEI system does, at the present status, not reach the target performances given in the specific objectives. However, it has been demonstrated by the other partners in the EU-project that the system worked in a homogeneous media (water tank) and, when using echo-reflection from a signal test surface, the instrument could detect a variety of targets in concrete samples. This is a necessary step in proving the correct operation of the system and also encouraging step for the future development of the operational system.The overall conclusions from the evaluation of the RSIM system are positive: the method was found to have good sensitivity to structural changes in concrete beams caused by over-loading and corrosion of internal steel. Artificial neural networks were found to work well in detecting significant structural changes. All development tasks and the majority of evaluation tasks were completed successfully. There were, however, problems associated with long-term reliability of sensors, especially under the severe cold weather. The size of sensors seems too big to be easily handled. Therefore, the RSIM sensor needs to be re-engineered to be smaller and more reliable. More valuation tests would also be desirable