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IASS-SLTE Symposium 2014: Shells, Membranes and Spatial Structures: Footprints


IASS Symposium 2014

SESSION: Hangai Prize Presentations

Analytical estimation of critical buckling load for guyed towers

< Table of Contents for Hangai Prize Presentations
  • Proceedings Name: IASS-SLTE Symposium 2014: Shells, Membranes and Spatial Structures: Footprints
  • ISSN: (Electronic Version) 2518-6582
  • Session: Hangai Prize Presentations
  • Title: Analytical estimation of critical buckling load for guyed towers
  • Author(s): Georgia MARGARITI, Charis J. GANTES
  • Keywords: Guyed tower, cable, buckling, equivalent buckling length, geometric nonlinearity
Abstract
In this paper an approximate method already proposed by previous researchers is first presented for quantifying the lateral resistance offered by the inclined cables to guyed towers, such as the pylons of cable stayed bridges. For that purpose, an analytical expression is derived for the evaluation of the effective buckling length of the pylon based on linear buckling theory. For simplification, a simple pylon is considered, supported laterally at the top by a set of symmetrically arranged inclined cables and being either fixed or hinged at its base. Taking into account cables inclination and prestressing and approximating the non-linearity due to sag with Dischinger's formula, the cables are substituted by a horizontal spring of equivalent stiffness. Then, the above substitution is employed in order to evaluate the effective buckling length of the pylon, making use of the well-known stability formula for compressed bars. In the second part of the paper, the stability of such structures is investigated by means of nonlinear finite element analyses. Namely, the analytical solution is compared to numerical results, which are generated through linearized buckling analysis (LBA) of the spring-supported pylon as well as geometrically nonlinear analysis with initial imperfections (GNIA) of the actual cable-supported pylon, employing finite element software ADINA. The unstable nature of the post-buckling response and the imperfection sensitivity of such structures are highlighted and design implications are discussed.

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