Damping assessment of monopole steel structures through full-scale experiments

This paper investigates the modal damping ratios of steel monopole structures, with a focus on their relevance in structural design. Full-scale dynamic identification tests were conducted on three distinct monopoles to reveal damping values in relation with wind speed and motion amplitude. Additional data from the literature on similar structural typologies are incorporated providing information on the testing methodologies and motion amplitude. Finally, the data are categorized to identify primary trends across monopole structures, supplying information on damping ratios useful for structural dynamic response calculations. Particular attention is given to the damping ratio of the second vibration mode, focusing on a specific case where it is significantly lower than that of the fundamental mode. In such cases, regulatory standards may lead to overestimations of structural damping, potentially resulting in non-conservative design assessments.