Modelling of Aeolian Vibrations of Single Conductors Strung at Relatively High Tensile Load

It has been shown that analytical methods based on the EBP and a shaker-based technology can provide a useful design tool for damping systems that protect a single conductor against aeolian vibration. It is then important to evaluate the effectiveness of these methods for the design and/or verification of the damping system of long, single conductor spans strung at relatively high tensile load, such as crossings, which need more than one damper per span extremity to be effectively damped against aeolian vibration. As in the first two sections, this one is based on an analysis of the available technology and on the results of two benchmarks: an analytical–analytical benchmark and an analytical–experimental one. The comparison between the analytical results produced by the different available models and the experimental one helped to understand the limitations and the usefulness of the approach. The WG focused its attentions on long spans that are more critical than standard length spans discussed in the two previous sections. In fact, the longer the span length, the more unrealistic is a constant wind profile along the line, especially at the low wind speeds required to produce aeolian vibration. Moreover, an additional parameter which becomes significant for large sags is the tensile load variation along the span. It affects the conductor vibration wavelength. In the work, it was demonstrated that, the use of the EBP approach, i.e. the assumption of a constant wind speed along the span, for long span applications should guarantee predicted vibration amplitudes higher than those that occur in reality, therefore producing conservative damping system designs. However, future research work is needed: • to improve the EBP technology, which generally produces a safe design of the damping system; • to better understand the effect of turbulence and mean wind speed variation; • to better simulate the mechanical system, in such a way to reproduce tensile load variations and multi-frequency excitation.