Inspecting the Unknown (Available in Geo-Environmental Special Issue Only)

by Scott H. Slaughter, P.E., Dir. of Operations; FDH-North America, L.L.C., Mobile, AL,
Robert A. Douglas, Dir. of Res.; FDH Inc., Raleigh, NC,
J. Darrin Holt, P.E., Vice Pres., Dir. of Data Analysis; FDH Inc., Raleigh, NC,

Serial Information: Civil Engineering—ASCE, 1998, Vol. 68, Issue 10, Pg. 11A-16A

Document Type: Feature article


Unknown foundations have plagued civil engineers for years. In the case of underwater pilings, much time and money is spent inspecting for cracks, breaks or deterioration. Even then, visibility and access limit the effectiveness of a dive team. Inspections are only effective for a pile's exposed portion, and damage below the mudline is frequently overlooked. Now, a new technology developed by FDH, Inc., Raleigh, N.C., can provide critical information about foundation conditions and embedment. Any brisk blow to a piling creates a wave that travels both through and up and down the piling. By measuring the wave's velocity and frequency reflections, engineers can determine that approximate distance to damage. FDH's dispersive wave technology has been used successfully by several engineering firms and transportation departments.

Subject Headings: Inspection | Foundations | Wave velocity | Underwater surveys | Transportation engineering | Team building | Geotechnical engineering

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