Nondestructive Strength Evaluation of Pinus Sylvestris Poles in the U.K.
Ronald W. Anthony
EDM, Inc. 4001
Automation Way Fort
Collins, CO 80525 U.S.A.
Lee Renforth
IPEC, Ltd.
University of Manchester
Dover St.
Manchester M13 9PL
Robert F. Nelson EDM,
Inc. 4001 Automation
Way Fort Collins, CO
80525 U.S.A.
ABSTRACT Pinus sylvespoles are used extensively to support overhead power lines in the U.K. This paper presents the results of a testing program involving correlation of stress wave parameters to destructive bending test results on approximately 100 full-size poles. Poles removed from service were subjected to a low-level impact to generate a transverse stress wave in the pole. Measurements of frequency distribution and attenuation were correlated to fiber stress values recorded at the time of failure during cantilever bending tests. The results of the correlation showed that the stress wave method can predict the bending strength of in-service poles with greater accuracy than visual inspection methods currently used in the field. New poles were subjected to longitudinal stress waves prior to destructive testing. Comparing the ability of the stress wave method to properly classify poles (by strength) to visual grading using British Standard 1990 illustrated that the strength grading approach is able to recognize tip-bad ~city that is currently unavailable to designers due to the conservative nature of visual grading rules.
Publication Source: WCTE '98 - 5th World Conference on Timber Engineering, 1998 August 17-20, Montreaux, Switzerland.
Vol. 1, Pages 642.....
Publisher: Presses polytechniques et universitaires romandes - [Homepage]
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