Free vibration of guyed antenna towers

摘要

Guyed antenna towers are used extensively in the telecommunications industry. Dynamic loads arise from extreme winds and earthquakes, impact due to sudden failure of cables, galloping of guys, sudden ice shedding from ice-laden guys, etc. The dynamic analysis of towers designed to resist different wind and ice loads is presented in this paper. This analysis includes the out-of-plane vibrations of guys and torsional and axial modes of the masts. A general finite element commercial package "ABAQUS" was used in which the latticed mast of the tower is modelled as three dimensional truss elements and beam-column elements and guys as cable elements. The natural frequencies and mode shapes obtained through these models are presented. For the purpose of verification, triangular steel latticed guyed tower models were constructed and the dynamic characteristics of these models were obtained and compared to theoretical results. The paper summarizes the results of an analytical and experimental investigation which was conducted to identify key parameters affecting the natural frequencies and mode shapes. Also the influence of the torsion-resistors and telecommunication devices on the essential dynamic characteristics of these towers is reported. Recommendations are made regarding the applications of the different analysis procedures for various design situations.