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January/February 2001
Internal FHWA Partnership Leverages Technology and Innovation (continued)
Collaboration in Geotechnical Testing
Another type of nondestructive testing was involved in a joint RD&T/Central Federal Lands Highway Division project to evaluate the use of cross-hole sonic logging (CSL) with tomographic software to create images of defects in structural concrete. Although three-dimensional (3-D) tomographic imaging is routinely used in the medical, petroleum, ceramics, and other industries, its application to the geotechnical field is relatively new. CSL, a geophysical wave propagation technique, is the standard method to determine the integrity of deep concrete foundations and the concrete structure integrity in drilled shaft piers; however, data from waveform traces or "XY time versus distance" plots are difficult to interpret. The 3-D format of data presentation - a "through the earth CAT scan" with accurate 3-D images of the shaft interior in near real time - is much easier to interpret. The data gained from three separate case studies will help in the development of sonic technology and software data analysis techniques that can be used for a wide range of subsurface geotechnical and geological mapping applications, including the analyses of slopes, embankments, and impoundment stability.
RD&T and FLH are also involved in a pooled-fund study to evaluate the GeoGauge (formally known as the Soil Stiffness Gauge), which was developed by FHWA, the Department of Defense's Advanced Research Programs Administration, and the Humboldt Manufacturing Co. The GeoGauge measures directly and rapidly the stiffness (resistance of a layer of material to deformation) of soils, soil-aggregate mixtures, and stabilized soil mixtures. As of November 2000, 22 states have pledged funds, and eight other states have indicated an interest in participating in the study.
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Other Articles in this Issue:
Safe Plowing - Applying Intelligent Vehicle Technology
Improving Roadside Safety by Computer Simulation
Using the Computer and DYNA3D to Save Lives
LS-DYNA: A Computer Modeling Success Story
Preservation of Wetlands on the Federal-Aid Highway System
Internal FHWA Partnership Leverages Technology and Innovation
New Applications Make NDGPS More Pervasive
Center for Excellence in Advanced Traffic and Logistics Algorithms and Systems (ATLAS)
National Work Zone Awareness Week (April 9 to 12) - Enhancing Safety and Mobility in Work Zones
