The effect of orthotropic behaviour on form finding of shell structures

Abstract

Shell structures are being extensively utilised within the building industry, due to their ability the span over large distances, using minimal structural material, without the need of interruption by supports, within the span distance. Architects and engineers have tried to develop many forms to provide better transfer of loads, while keeping an aesthetical form. Introducing structural knowledge in early stages of the design process, could offer more possibilities of improving efficiency in the construction process. Form finding techniques have been adopted to be able to produce more efficient, and optimised forms. With the introduction of new materials, particularly materials behaving in an orthotropic manner, these material behaviours became an interest on how they would be implemented in the form finding process to be able to produce more efficient forms, which follow this structural knowledge. The objectives of this dissertation are to propose a method of applying orthotropic properties to a form-finding process and to obtain connections, between the effect of orthotropic behaviour and other parameters which generally affect the form-finding process. The main parameters assessed are the building topology and the support conditions. Using Karamba3d shell form-finding techniques, an application of orthotropic material properties was introduced to a parametric form finding process to be able to assess the effects produced on the square, rectangular and circular forms, with varying parameters. The main findings of the dissertation were that the topography of the form to be assessed determines the effect of the orthotropic behaviour. Furthermore, the orthotropic behaviour, in the orthogonal directions of the form being analysed, has a more applicable effect on forms a having geometrically dominant direction, such as the rectangular form. Also, it was shown how parametric form-finding can be beneficial to implementations in early stages of the design process, due to being easy to use and obtain fast, graphical results, with no extremely large computational efforts.