Condition assessment tool for timber utility poles using stress wave propagation technique

Timber utility poles are significantly used in power and telecommunication infrastructures all over the world. The deterioration of timber with time is common due to various factors including termite attacks and climatic conditions. Failure of poles can have serious safety concerns and economic implications. Hence, the condition assessment of timber poles is important for safe and economical operation of the power network. This paper presents the development and application of a non-destructive testing tool using stress wave propagation technique for the condition assessment. Shear waves are generated in timber poles by the application of transverse impacts and both the generated and reflected waves are recorded for further analysis. Short Kernel Method is used as a signal processing technique to address the dispersive nature of the generated shear waves and developed technique is validated with numerically simulated signals using ANSYS finite element programme. The pole condition estimation software is developed and implemented within the tool for on-site assessment. The developed tool is tested using laboratory and field-collected signals from in-service poles. Further, the effects of pole length, age and diameter for stress wave propagation velocity are investigated with the use of a database of collected stress waves using the developed equipment.