Geology topics
Publications and source records attributed to Roy E. Trent.
This paper briefly summarizes more than 470 measurements of local channel scour at bridge piers from 58 sites in 14 States. Relations between local scour and selected deterministic parameters are illustrated and discussed. Observed scour depths are compared with predicted values from two local scour prediction equations.
A portable instrumentation system is being developed to obtain channel bathymetry during floods for detailed bridge-scour measurements. Portable scour measuring systems have four components: sounding instrument, horizontal positioning instrument, deployment mechanisms, and data storage device. The sounding instrument will be a digital fathometer. Horizontal position will be measured using a range-azimuth based hydrographic survey system. The deployment mechanism designed for this system is a remote-controlled boat using a small waterplane area, twin-hull design. An on-board computer and radio will monitor the vessel instrumentation, record measured data, and telemeter data to shore.
A study to collect and analyze field measurements of bridge scour is being conducted by the U.S. Geological Survey in cooperation with the Federal Highway Administration. The primary objective of this study is to collect measurements of bridge scour as it occurs during floods to improve the ability to understand and predict scour processes. Scour measurements are classified as limited or detailed depending on the range of information to be collected. Many scour measurements were obtained during floods in 1990. A data-base system is being developed to assist in documentation, compilation, and analysis of these data. Scour measuring instrumentation and techniques have been and continue to be developed in this study. The study will provide data needed to improve the understanding and prediction of scour processes.
Ten people died on April 5, 1987 as a result of the collapse of two spans of a New York State Thruway bridge into the floodwaters of Schoharie Creek. The cause of the bridge failure was determined to be scour of bed material from under the foundations of piers supporting the bridge. To evaluate the hydraulic conditions that produced the scour, a two-dimensional finite element surface-water flow model was constructed. The model was used to obtain a detailed description of water-surface elevations and depth-averaged velocities within a reach that extends from about 4000 ft downstream of the bridge to about 6000 ft upstream of the bridge.