الفهرس | Only 14 pages are availabe for public view |
Abstract Guyed towers are a type of tall steel towers which used for some different purposes, for example communications industry, windmills, transmission of phone signals by aerials over long separation, for supporting collectors in sun powered vitality applications, and for supporting tall chimney and offshore oil operations. Guyed towers consist of a vertical continuous central shaft laterally supported at several levels along its height by sets of inclined pre-tensioned guys. Such shafts often have flexible cantilever at the tops. The shaft itself is often a triangular lattice structure, although square lattice or cylindrical structure are also used. The individual members may be designed from tubular or angular steel sections. The joints may be riveted, bolted or welded. The key objective of the present work is to analyze guyed towers considering two different mathematical models to know the difference in response of the two models. The shaft of one of the models is modeled as line beam element with equivalent section, and other is modeled as a three-dimensional space truss as vertical legs with horizontal and diagonal lacing. The static and dynamic analysis of several guyed towers are carried out for the two mathematical models to study their behavior due to various sets of significant parameters under the effect of various loads. These loads include, dead, live, earthquake, and wind loads. Finally, the results of the analysis were discussed in detail then, a brief summary of the conclusions as well as the recommendations were introduced in the last chapter of the thesis. |