UBC Theses and Dissertations
A case study in the conceptual design of an anodized aluminium cladding system for a steel torus structure Fitch, Devan Carless
Typically, structural systems, such as cladding panels are used to achieve a desired architectural appearance, enclose building envelopes and act as barriers to ingress of the external environment. Due to the large surface area of such applications, efficient design of these panels is of paramount importance, if a cost effective solution is to be achieved. Existing structures utilizing cladding systems typically consist of flat rectangular panels enclosing a regular and rectangular building. For this design project, the structure to be enclosed is a torus structure, and in order to achieve an aesthetic appearance which is acceptable to the client, both curved and flat panels are investigated. Through careful review of available literature, parasitic cladding panels (these do not resist global loads) are selected over a stressed skin (architectural fabric) structural solution due to the highly non-linear and hence complex behaviour of the latter coupled with the fact that the particular geometry of the structure considered in this project does not readily lend itself to implementation of a stressed skin solution. Anodized aluminum is selected over composite materials for the cladding panels, due to the higher confidence level in achieving the desired aesthetic appearance of the panels, and the long-term durability of this appearance with this material. The design of flat cladding panels is relatively simple and there are many analytical solutions available in the literature. However, there is little information that can be found in the literature regarding the conceptual design of curved cladding panels. The structural design of curved panels subject to environmental loading such as uniform normal pressure and thermal gradients is complex due to their nonlinear behavior and susceptibility to buckling. A finite-element (FE) investigation into the influence of panel parameters including; geometry, support conditions and stiffening elements on design efficiency is conducted. From the results of the investigation, a reasonable approach to the design of curved aluminum panels is outlined; starting with analytical methods of structural analysis o f un-stiffened panels and progressing to finite element analysis of longitudinally and radially stiffened panels with discrete supports. Throughout this thesis, charts are developed which will simplify and direct future analysis. They might be helpful for the conceptual design of these panels. Areas of concern and of particular importance are identified, allowing these aspects to be considered at the outset of a project, when decisions and changes can be made more readily and with fewer consequences in terms of budget and schedule over-runs.
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