Repair and replacement of deteriorated bridge decks represent a major expense to many state highway agencies. current techniques forassessing deck condition have limited the effectiveness of efforts to program, order by priority, and estimate maintenance and rehabilitation (m&r) projects. a research program sponsored by 5 new englandstates led to the development of ground penetrating radar as a rapid and accurate means for deck deterioration assessment. the program involved surveys of 32 asphalt-overlaid decks in the region, 28 of which were studied during maintenance for deterioration quantities. before maintenance, radar was collected on all of these decks and analyzed. analysis techniques were developed to predict the concrete deterioration from the variations in the concrete dielectric constant as computed directly from the radar waveforms. the computation was used to predict overall deterioration for each deck and each major span. this prediction was then correlated with the actual deck deterioration determined when the asphalt overlay was removed and the bare concrete was visually examined and chain-dragged. correlations were carried out both at a detailed project level (100% coverage) with underside survey, and a network level (30% coverage). the project-level correlation produced a good fit (r squared equals 0.83), with standard error of plus or minus 4.1% of the deck area. the network-levelcorrelation produced a reasonable fit (r squared equals 0.72) with standard error of plus or minus 5% of the deck area. both project and network survey methods have subsequently been implemented at highway speed, at costs comparable to traditional survey methods. this paper appears in transportation research record no. 1304, highway maintenance operations and research 1991.
Samenvatting