Geology topics

D.M. Sheppard

Publications and source records attributed to D.M. Sheppard.

3 recordsLinked to original sources

USGS2012

Clearwater local scour experiments in a large flume

Local sediment scour experiments have been conducted with 0.114 m, 0.305 m and 0.914 m diameter circular piles in a 6.1 m (20 ft) wide by 6.4 m (21 ft) deep by 38.4 m (126 ft) long flume in the Hydraulics Laboratory at the USGS Conte Laboratory in Turners Falls, MA. All of the tests to date have been in the clearwater scour range of velocities and with two near uniform diameter sediments with median diameters of 0.2 mm and 0.8 mm. All tests were conducted with steady, fully developed flows. This paper describes the procedures and instrumentation used in these tests and outlines the live bed scour experiments that are planned after the completion of the clearwater tests. Copyright ASCE 2004.

Conference Paper↗

USGS2012

Hydraulic modeling and scour analysis for the San Francisco - Oakland Bay Bridge

A study was conducted to determine potential maximum scour depths for the foundations of the replacement east span of the San Francisco-Oakland Bay Bridge, as part of the ongoing structural design. This effort presented unique challenges as strong tidal currents, large depths, and cohesive bottom sediments characterize the site. The authors met these challenges with a multi-faceted approach to the problem. First, design current velocities were determined using a two-dimensional hydrodynamic model of San Francisco Bay in conjunction with ADCP hydrographic surveys. Analytical scour calculations were performed and live-bed flume tests of the proposed foundations were also conducted. Finally, two separate methodologies were used to interpret the physical model tests in order to calculate potential scour depths around the foundations. Copyright ASCE 2004.

Conference Paper↗

USGS2004

Large scale clear-water local pier scour experiments

Local clear-water scour tests were performed with three different diameter circular piles (0.114, 0.305, and 0.914 m "> 0.914 m ), three different uniform cohesionless sediment diameters (0.22, 0.80, and 2.90 mm "> 2.90 mm ) and a range of water depths and flow velocities. The tests were performed in the 6.1 m "> 6.1 m wide, 6.4 m "> 6.4 m deep, and 38.4 m "> 38.4 m long flume at the United States Geological Survey Conte Research Center in Turners Falls, Mass. These tests extend local scour data obtained in controlled experiments to prototype size piles and ratios of pile diameter to sediment diameter to 4,155. Supply water for this flow through flume was supplied by a hydroelectric power plant reservoir and the concentration of suspended fine sediment (wash load) could not be controlled. Equilibrium scour depths were found to depend on the wash load concentration.

Journal of Hydraulic Engineering↗