الفهرس | Only 14 pages are availabe for public view |
Abstract The main objective of the present work is to research the best shape of guyed towers and its cables arrangement. Method of minimizing the total potential energy (TPE) using the conjugate gradient (CG) technique to predict the static response of guyed towers is introduced. Time domain analysis by expanding the method of minimizing total potential energy to include dynamic loads and responses is also presented. The previous analysis method was used to predict the structural behaviour of guyed tower. The structural behaviour of guyed towers is influenced by a number of parameters which make their analysis highly complicated. These parameters comprise tower shape, cables arrangement and its fastening to the ground, and initial tension of cables. The influence of these key parameters on the shape optimization of guyed towers is studied. Three really constructed guyed towers are analyzed due to equivalent static wind loads. The optimization of the shape of these towers is examined as a function of the above mentioned key parameters. In this study, the influence of cables arrangement which include, the number of cables in each level and their inclination angles with vertical, is considered. The shape of the tower is also varied to include square, pentagon, and hexagon shape. Both static and dynamic analyses of the guyed towers are considered. The loads which are taken into account in this analysis are the selfweight of the structure in addition to the wind forces resulting from the effect of gust wind having speed of 30m/sec at height 10 ms. from the ground. The action of the wind forces calculated at the nodes of the cables and the joints of the shaft were taken in a case as equivalent static loading and in another case as sudden or shock dynamic loading. Final conclusion, deduced from the analysis of the different cases of study, has confirmed the superiority of the towers having triangular cross section shape over the other shapes (square, pentagon, and hexagon). The study has also proven that, using parallel cables arrangement initially tensioned by 15% of the breaking force of the cables has greatly improved the structural response of the studied towers. |