Collection of Historic Live-Bed Scour Data at Selected Bridgesin South Carolina using Ground-Penetrating Radar

摘要

The U.S. Geological Survey (USGS) in South Carolina, since 1996, has beenusing historic scour data collected from field investigations to develop regionalenvelope curves for clear-water abutment, contraction, and pier scour. The USGS iscurrently collecting historic live-bed scour at selected sites in South Carolina with thegoal of developing similar regional envelope curves for live-bed scour. Thecollection of historic scour data is relatively simple for clear-water scour because thescour holes do not refill. The measurement of historic live-bed scour, however, canbe problematic because of the partial or total refilling of scour holes by channelsediment. To address this problem, a geophysical technique, ground-penetratingradar (GPR) can be employed to assess buried scour surfaces. Starting in 2005, theUSGS has used GPR to collect measurements of historic live-bed contraction and pierscour at 56 bridges in South Carolina. While there are limitations and uncertaintyassociated with scour measurements made with GPR, the data should yield valuableinsights into regional trends of live-bed contraction and pier scour in South Carolina.