Shield, Carol K.2013-06-262013-06-261999-01https://hdl.handle.net/11299/151795This system consists of acoustic emissions sensors, preamplifiers, filers, an AE monitor, and a digital oscilloscope. The system has been applied successfully to both steel and concrete structures and used to detect brittle fracture and low-cycle fatigue failures in welded steel joints and crack propagation in cover-plated rolled bridge girders, in the field and in the laboratory. The AE system detected initial cracking during the flexural crack testing of two high-strength concrete prestressed bridge girders. The acoustic emission monitoring of bond tests also provided insight into the behavior of the bond between glass fiber reinforced polymer rebar and concrete.en-USAcoustic emissionBridge girdersDigital oscilloscopeMonitoringReport