Locking Into Success

by Brian H. Greene, Engrg. Geologist; U.S. Army Corps of Engineers, Pittsburgh, PA,
Andrew Schaffer, Geotechnical Engr.; U.S. Army Corps of Engineers, Pittsburgh, PA,
Donald A. Bruce, Technical Director; Nicholson Construction Company, Bridgeville, PA,
John A. Gerlach, Geotechnical Engr.; U.S. Army Corps of Engineers, Pittsburgh, PA,

Serial Information: Civil Engineering—ASCE, 1994, Vol. 64, Issue 4, Pg. 48-50

Document Type: Feature article


In 1961, at Wheeler Lock in Alabama, crews with the Tennessee Valley Authority tried to incorporate an existing lock wall into a new cofferdam. A major portion of the land wall slid about 30 ft into the dewatered excavation being used to construct the adjoining lock, killing several people. Reportedly, sliding occurred on an undetected weak clay seam in the foundation rock. No stabilization measures or instrumentation systems had been implemented. Now 30 years later, designers with the U.S. Army Corps of Engineers, Pittsburgh district, have installed a similar project at Point Marion Lock in Pennsylvania to replace the 68-year-old navigation lock on the Monongahela River in southwest Pennsylvania. This time, designers called for 471 anchors--one of the largest single uses of prestressing strand in North America--to avoid repeating the Wheeler Lock failure. The project cost $88 million. Had a new site been selected that required the construction of both a new lock and dam, the project would have cost approximately 50% more. Designers also created an extensive $1 million structural and geotechnical instrumentation program for this project.

Subject Headings: Project management | Locks (dam) | Walls | Locks (waterway) | Landslides | Instrumentation | Federal government

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