About the research
This project investigated the application and implementation of stress-wave based methods for assessing the integrity of concrete bridge decks. The ultimate objective is to develop reliable and economical non-destructive evaluation (NDE) techniques that evaluate the condition of concrete bridge decks in the field with limited traffic disruption. Experimental and theoretical studies were conducted on guided stress waves (Lamb waves) in concrete plates. Field measurements were performed on a full-scale concrete bridge deck located at the Remote Testing Facility (RTF) at the University of Missouri, Columbia. Measurements were performed using a variety of sensor and source orientations, including the placement of sensors on the opposite side of the concrete deck from the source. Energy was excited using vertically and horizontally oriented broadband source impacts. Dispersion curves were successfully developed from a single-sensor, multi-impact approach and a frequency-wavenumber transformation procedure. The dispersion curves that were developed demonstrated the ability to detect and separate multiple Lamb wave modes that could be used to infer the thickness and Rayleigh wave velocity of the concrete deck.
A second series of field experiments was performed on a concrete element containing simulated defects at several depths. The implementation of the approach described above proved ineffective for clearly detecting the presence and depth of the flaws. Additional measurements of Lamb waves propagating past the subsurface defects demonstrated the potential to identify the presence and depth of flaws based on changes in the frequency content of the wave. These measurements have provided valuable insight into potential means to implement stress-wave measurements for defect detection in bridge decks.
Federal Highway Administration
Midwest Transportation Consortium