9812574 Chang A joint investigation between U.S. and Japanese investigators is conducted to develop built-in diagnostic techniques for the monitoring of the integrity of civil infrastructures. On the U.S. side, this investigation will focus on the development of an active sensing diagnostic technique for identifying anomalies in critical areas of structures. On the Japanese side, a passive sensing technique with distributed sensors for monitoring the global response of the structures and for locating the critical areas where anomalies might be present. This research will involve the development of both the hardware and software for the system. The hardware development includes the design and fabrication of the smart rebar for steel- reinforced concrete structures. The smart rebar will be made of composite materials with a built-in network of sensors and actuators. Piezoelectric materials will be selected as both sensors and actuators. A built-in actuator would generate desired diagnostic signals which are sensitive to a particular type of anomaly or damage, and the neighboring sensors would record the transmission and reflection of the signals. The difference in sensor measurements taken before and after the introduction of an anomaly in the region will then be processed to identify the presence of the anomaly. The software will be developed to interpret the sensor measurements. The major focus of the development of the software will concentrate on diagnostic signal generation by built-in transducers, signal processing, and signal interpretation, thus serving as the brain of the diagnostic technique. Upon completion of the study, a prototype of a built-in active sensing system will be developed. Appropriate experiments will be conducted for verifying the proposed techniques. ***
