Wind-induced dynamic behaviour of slender structures

: tall buildings and electricity transmission lines

Abstract

The design of more slender buildings and the elongation of the spans for cable structures increase the concerns of wind-induced vibrations and aerodynamics and aeroelastic phenomena. Despite nowadays greater awareness and better knowledge of such problems, there are still several uncertainties on the wind-structure interaction, modelling omissions and weakness in understanding the exact mechanism of the underlying phenomena. This research presents results from simple full-scale monitoring approaches for two types of slender structures, two tall buildings and a cable bundle within an electricity transmission line, which was also studied at wind tunnel-scale.
Full-scale measurements were taken of accelerations measured on the two tall buildings and the associated wind conditions to quantify the dynamic behaviour and the effect of the relative orientations of the wind and motion on the modal parameters, i.e., natural frequencies and damping ratios. These parameters have been investigated in relation to a series of variables and supported by a simplified finite element model of one of the structures to assess the long-term variation of the observations. A new empirical amplitude-dependent damping prediction model has been also developed to quantify this relationship in comparison with a series of previous studies.
In order to increase the understanding on the interaction between wind and slender structures, this research has been extended to transmission lines by means of a full-scale analysis founded on a preliminary groundwork study, based on experimental wind tunnel test data, to investigate the analytical solutions to assess the galloping stability from two existing aeroelastic formulations in literature. In particular, a new study based on the eigenvalue analysis has been presented, for which the calculated stability regions and steady-state responses have been assessed and compared with the published model and wind tunnel tests.

Date of Award	3 Oct 2023
Original language	English
Awarding Institution	University of Bristol
Supervisor	Branislav Titurus (Supervisor), Djamel Rezgui (Supervisor) & Raffaele De Risi (Supervisor)