Estimating critical shear stress of bed sediment for improved prediction of bridge contraction scour in Georgia / submitted by Terry W. Sturm, Seung Ho Hong, and Paul Hobson GDOT research project ; no. 404 Sturm, Terry W. Hong, Seung Ho Hobson, Paul. Georgia. Dept. of Transportation. Office of Materials and Research. Georgia Institute of Technology. School of Civil and Environmental Engineering. United States. Federal Highway Administration Scour at bridges--Georgia Scour at bridges--Georgia--Evaluation Sediment transport--Georgia Shear (Mechanics)--Mathematical models "December 2008"--Cover. "FHWA-GA-08-0617." "Prepared in cooperation with the U.S. Department of Transportation, Federal Highway Administration." "Performing organization... Georgia Institute of Technology, School of Civil & Environmental Engineering." Includes bibliographical references (leaves 54-55). Final report; July 2006-Dec.2008. "The influence of sediment properties and the flow field on bridge contraction scour are investigated in this study. Sediment properties of samples obtained from Shelby tube cores at 5 bridge sites in Georgia are tested using an erosion flume and a rheometer. Relationships for the critical shear stress are developed from this data to be used in contraction scour formulas. The effect of the flow field on contraction scour is investigated by conducting a physical model study of the SR 42 bridge over the Towaliga River in central Georgia. Physical model results for contraction scour depths are shown to match field measurements rather well. Based on this favorable comparison, conclusions are drawn concerning the interaction of local scour and contraction scour with suggestions for further research on scour near an abutment under submerged bridge flow conditions." SPR00-0007-00-073 Athens, Ga. : Digital Library of Georgia University of Georgia. Libraries Text http://dlg.galileo.usg.edu/ggp/query:%28estimating+critical+shear%29 application/pdf [Forest Park, Ga.] : Georgia Dept. of Transportation, Office of Materials and Research, 2008. vii, 61 leaves : ill., col. map, col. photos ; 28 cm. Georgia