| Summary: | 碩士 === 朝陽科技大學 === 營建工程系碩士班 === 98 === Due to global warming, the intensity of typhoons tends to be stronger and thus seriously threatens the safety of power lines. To enhance capacity in resisting wind loads, prestressing technique has been applied to the fabrication of pole structures. As a result, this study aims to investigate the effect of prestress losses on the behavior of pole structures and the validity of formulas in the traditional analysis procedure.
In this study, prestressing effect was simulated by temperature effect and the feasibility was confirmed. The realistic stress distribution of the cross section was then studied with 3-dimenional FEM models. Parametric studies showed that the difference between predicted tensile stresses by the FEM model and the uniform assumption can be as large as 20% or so. Therefore, the traditional simplified theory regarding line members may potentially result in non-conservative predictions. For case studies of 9m poles with wind loads acting on simultaneously, it was found that the critical region for tensile stresses is located within 1.5 to 2 meters from ground line. Modifications to design details at such region would then be of particular interests.
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