Adoption of a reliability approach for membrane structure analysis

Abstract

Membrane structures, including tensioned fabric and pressurized foil, feature in high profile and large span projects throughout the world for well-appreciated architectural and functional reasons. From an analysis and design perspective these types of structure exhibit high levels of material and geometric non-linearity. Current design practice is use of a permissible stress approach using stress reduction factors with values typically between 4 and 8. Design guidance is limited and the magnitude and nature of these stress factors varies widely.Recently CEN TC250 Working Group 5 has been established to write a standard for membrane structures for inclusion in Eurocode 10. In this paper we apply the principles of BS EN 1990:2002 “Eurocode – Basis for Structural Design” to membrane structures and explain the implications for analysis and design. The key feature of this approach is the mathematical and numerical rigor and consistency in predicting the safety of membrane structures as an explicit function of inherent uncertainty in applied loading, structural form and material properties. This new approach to membrane structure analysis is demonstrated through two examples, which show the application of reliability analysis in achieving the objectives of “Eurocode – Basis for Structural Design” and highlight the further work that is required before this approach can be fully utilized by industry.