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Project

Wind load identification on guyed masts using inverse model-based techniques

Guyed mast telecommunication towers are highly complex structures that require special attention in their design under wind loads (both quasi-static and dynamic components). These structures are particularly sensible sensitive to wind loads due to their high exposure, absence of redundant elements that provide additional stiffness to the system, low structural damping, large flexibility and lightweight character, low natural frequencies, non-linear behavior and the complex interaction between cables and shaft under fluctuating wind loads. The analysis of these structures is currently carried out by representing the wind in terms of forces obtained through equivalent static methods, which are applied to the shaft and the cables of the tower, or using dynamic approaches in frequency or time domain. Due to their simplified nature, these procedures do not allow us to consider the full complexity of the wind-structure interaction, nor the shaft-cable interaction under wind load. An additional challenge in the analysis of guyed mast structures is given by the difficulty in obtaining computational models that accurately reflect the real characteristics of the structure. The main aim of this research is to overcome these challenges using Operational Modal Analysis methods, where modal data, such as natural frequencies, mode shapes and modal damping ratios are extracted from vibration measured by sensors on the structure under ambient excitation, avoiding forced excitation by shakers or impact devices. In the case of guyed masts, the modal data can be used to calibrate a model of the structure which can, subsequently, be used in an inverse approach to estimate wind loads from vibration data obtained under wind excitation. If these sensors are combined with anemometers that simultaneously measure the wind speeds acting on the tower, the estimated wind loads can be validated and further improved. It is anticipated that such a procedure will allow to properly assess the dynamic response of a tall guyed mast, dealing with two of the most important challenges: construction of a more accurate dynamic model and more precise estimation of wind loads, using a model-based approach, with combined data from accelerometers, strain gauges and anemometers.

Date:24 Feb 2021 →  Today
Keywords:wind load, guyed masts, operational modal analysis, wind load identification, inverse model-based approach
Disciplines:Structural engineering, Wind engineering, Kinematics and dynamics
Project type:PhD project