The Benkelman beam is commonly used to measure surace deflections of highway and airfield pavements. The Benkelman beam is based on a simple lever-arm principal and uses dial guages to measure surface deflections under an applied axleload. The Road Rater is an electro-hydraulic testing device that applies a sinusoidal force to the pavement at a fixed amplitude and frequency: surface wave velocities are measured and electronically integrated to obtain surface deflections. Road Rater and Benkelman beam deflections have been successfully simulated using elastic theory and the Chevron N-layer computer program. The analyses presented in this paper illustrate relationships between Road Rater deflections and the more commonly used Benkelman beam deflections.

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The contents of this report reflect the views of the authors who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the University of Kentucky, of the Kentucky Department of Transportation, nor of the Federal Highway Administration. This report does not constitute a standard, specification, or regulation.

Prepared for the International Symposium on Bearing Capacity of Roads and Airfields (Trondheim, Norway: June 23-25, 1982).