Wood Utility Poles Research Articles

Strength‐Grading Method for Wood Poles

Based on a nondestructive evaluation (NDE) system, a methodology is described to develop a strength-grading method for wood utility poles. Considerations are given for both economics and engineering design aspects. The proposed NDE-based grading system is calibrated to provide at least the same production economic benefit and structural reliability as currently exist with visually graded poles. However, even with these limitations, an additional reliability and hence an additional economic benefit is derived by enabling a better matching of pole strength with specific design loads. Use of currently rejected poles is possible with the proposed method. The proposed grading system retains the size classification concept currently used by the American National Standard Institute, but would upgrade or downgrade individual poles according to their NDE-predicted strengths. Five strength grades are proposed that are calibrated to recently obtained bending strength data for transmission-size Douglas fir poles.

Modeling stress wave passage times in wood utility poles

The objective of this study was to develop an appropriate mathematical model to study the behavior of the stress waves in the radial-tangential plane of utility poles. It is hoped that such a study could increase the ability to use the sonic testing method in field testing procedures.

Computed tomography for measuring the annual rings of a live tree

A portable, high resolution X-ray CT (computed tomography) scanner has been developed for nondestructive measurement of the cross-section of live trees, wooden utility poles, building columns, statues, etc., in the field environment. The spatial resolution of CT reconstruction is good enough for observing the details of annual rings of trees. The scanner should be useful in plant physiology, environment assessment, safety assurance of poles, lumber milling, archaeology and dendrochronology.

Computed tomography for measuring annual rings of a live tree

A portable X-ray computed-tomography (CT) scanner has been developed for the nondestructive measurement of cross sections of live trees, wooden utility poles, wooden building columns, wooden statues, etc., in the field environment. Temporal resolution of CT reconstruction is good enough for observing details of annual rings of trees. The scanner shah be useful in plant physiology, environment assessment, safety assurance of poles, archeology, and dendrochronology.

Reliability of Wood Transmission Structures Through Nondestructive Evaluation

A Monte Carlo simulation technique is developed to predict the bending strength and stiffness distributions of new and in-service wood utility poles. The simulation is based on sonic nondestructive evaluation of poles and on correlations between destructive and nondestructive parameters. Excellent agreements were found between simulated and measured distributions for wood pole structures taken from a transmission line removed from service.

Reliability of Wood Transmission Structures Through Nondestructive Evaluation

A Monte Carlo simulation technique is developed to predict the bending strength and stiffness distributions of new and in-service wood utility poles. The simulation is based on sonic nondestructive evaluation of poles and on correlations between destructive and nondestructive parameters. Excellent agreements were found between simulated and measured distributions for wood pole structures taken from a transmission line removed from service.