Buckling Behaviour of Wooden Poles

Woodc:n poles are popular structural elements currently used by Manitoba Hydro for distribution lines and transmission towers. In recent years, a considerable number of such poles have failed duc to heavy build-up of ice on the lines. These failures may be attributed to the accuracy or reliability of the design methods and/or to the lack of adequate experimental information to evaluate the critical buckling strength of these poles. An experimental program, sponsored by Manitoba Hydro, was undertaken at the University of Manitoba to determine the behaviour and the load-carrying capacity of wooden poles. The poles were tested in a horizontal position, using a testing frame specially designed and built for this testing program. This paper presents the results of the experimental program of 58 test samples originated from ten poles representing two different wood species. The measured buckling strengths were compared to the predicted values based on the Canadian standard and three other existing models.