Assessment of wood utility poles’ deterioration through natural frequency measurements

Utility poles in a power distribution line are usually made of prestressed concrete, reinforced concrete or wood. In Latin America, given the abundance of different species of wood suitable for structural purposes, the latter material is more commonly used. The durability of wood in structures exposed to meteorological agents is usually an issue, especially when these have a critical role in the operation of industries or when the structures provide a service to society. For this reason, it is convenient to develop simple techniques that allow the assessment of the damage during their service life. In this paper, results obtained experimentally are contrasted with the outcomes of finite element models, taking deterministic property values of the material and simulating the same load state of the test. The correlation between the degree deterioration of wood poles and their dynamic behavior taking into account defects such as cracks, knots and others, was evaluated. The wood used in the experiments is Eucalyptus grandis, a species that is widely cultivated in South and Central America and particularly, found in the northeastern part of Argentina. The experimental work has been carried out in laboratory using real poles with different degrees of damage and deterioration, that were provided by the EDES, the electricity company that provides service in the Province of Buenos Aires, Argentina.