Characterizing the Seismic Behavior of Guyed Masts

Abstract

Guyed masts are specialised structures whose seismic performance is poorly understood. In this article, four existing guyed masts in the UK with heights ranging from 99–312 m are analyzed under various seismic loading conditions. The results are used to: gain an understanding of the magnitude and distribution of forces developed in guyed masts during typical seismic and design wind events, establish indicators and trends that may aid in guyed mast design, and identify the circumstances in which seismic loading may be the governing loadcase. The seismic responses of the masts are compared to indicative design wind analyses using the patch load method. Applicable sections of Eurocode 8 are followed wherever possible. It is shown that when subjected to seismic events with peak ground accelerations in the region of 4 m/s2, significant bending forces can develop that are comparable to those produced during a design wind assessment using the patch load method, with an actual mean hourly design wind speed in the region of 23 m/s. The remaining response forces of the mast are generally within the design wind force envelope. The peak seismic response to peak ground acceleration relationship is shown to be roughly linear and a number or trends are identified across the masts.