This IDEA project will develop an innovative smart-array antenna concept into a highperformance nondestructive evaluation (NDE) system for in-situ condition assessment of fiber reinforced polymer (FRP)-wrapped (or jacketed) structural members of concrete bridges. The array consists of multiple tiny antenna elements actively controlled by sophisticated electronics and software to focus microwave (in a GHz range) to a point of inspection. Invisible damage, such as air voids, cracks, and debonding between FRP jackets and concrete, is detected by scanning the focused microwave beam and analyzing the scattered wave signals. The proposed smart-array antenna represents significant technological advancement and advantages over the currently available NDE technologies. First, the system uses focused microwave (vs. unfocused one commonly used in ground penetrating radars) and, as a result, substantially increases the signal-to-noise ratio as well as the inspection depth. Second, the wave focusing and beam scanning are performed electronically by software, making it possible to investigate a large area in real time (without mechanically moving the array). Such high
performance, in addition to the portability, makes the proposed antenna system uniquely suitable for in-situ quantitative evaluation of damage in FRP-wrapped concrete members. The final report is available from the National Technical Information Service (NTIS # PB2007-107337).