The South Carolina bridge-scour envelope curves

Abstract

For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment-visit http://www.usgs.gov or call 1-888-ASK-USGS.For an overview of USGS information products, including maps, imagery, and publications, visit http://store.usgs.gov.Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. AbstractThe U.S. Geological Survey, in cooperation with the South Carolina Department of Transportation, conducted a series of three field investigations to evaluate historical, riverine bridge scour in the Piedmont and Coastal Plain regions of South Carolina. These investigations included data collected at 231 riverine bridges, which lead to the development of bridge-scour envelope curves for clear-water and live-bed components of scour. The application and limitations of the South Carolina bridge-scour envelope curves were documented in four reports, each report addressing selected components of bridge scour. The current investigation (2016) synthesizes the findings of these previous reports into a guidance manual providing an integrated procedure for applying the envelope curves. Additionally, the investigation provides limited verification for selected bridge-scour envelope curves by comparing them to field data collected outside of South Carolina from previously published sources. Although the bridge-scour envelope curves have limitations, they are useful supplementary tools for assessing the potential for scour at riverine bridges in South Carolina.

Benefits of Compiling and Analyzing Hydraulic-Design Data for Bridges

“…The soil characteristics of stream channels in the Coastal Plain generally consist of varying thicknesses of sand, underlain by sedimentary rock, and the floodplains consist of sandy alluvium deposits. (This information was summarized from Benedict et al [7] in which a map and additional information about the physiographic regions can be found. )…”

“…The USGS in cooperation with SCDOT conducted field investigations of scour at over 300 bridges in South Carolina (3,4,7). Data from these investigations were compiled into digital databases that included limited stream characteristics such as drainage area, stream slope, bank-to-bank channel width, floodplain width (left edge to right edge of water), sediment size, and flood flow depths and velocities for the 1% annual exceedance probability (AEP) flow, also called the 100-year flow.…”

“…The USGS bridge-scour investigations consist of a series of seven studies (1-7) conducted from 1990 to 2016, that were done in cooperation with SCDOT. The primary objective of these investigations was the advancement of the state-of-the-knowledge of bridge scour in the field setting, which led to the development of the South Carolina bridge-scour envelope curves (7). The USGS bridge-scour investigations have companion databases that include stream and bridge-hydraulic data for approximately 300 bridges.…”

“…The USGS bridge-scour investigations have companion databases that include stream and bridge-hydraulic data for approximately 300 bridges. Selected data from the databases associated with reports by Benedict and Caldwell (3,4), and Benedict et al (7) were used in the analysis presented in this paper, and the databases can be downloaded at the internet address included in the cited references. In addition to the USGS data, the SCDOT bridge-design database (unpublished) contains limited hydraulic bridge-design data for approximately 200 bridges previously designed to SCDOT standards.…”

Use of Laboratory and Field Data to Evaluate the Pier Scour Equation from Hydraulic Engineering Circular 18

“…The South Carolina Department of Transportation, in cooperation with the U.S. Geological Survey (USGS), has a long history of sponsoring field investigations of bridge scour. The primary objective of these investigations has been advancement of the state of the knowledge of bridge scour and the development of the South Carolina bridge scour envelope curves (1). An important product yielded by these investigations was the 2014 USGS pier scour database (PSDb-2014) (2).…”