Eurocode 3 (DD ENV 1993-1-1:1992) provides design guidance on the stability of rectilinear (beam and column) structural frames but it does not embrace the design of slender monotubular (curvilinear) arches, since it provides no information on geometric imperfections, buckling lengths or validated amplified sway moment expressions for such arches. This has arisen as a significant limitation in the preparation by CEN/TC 284 of a draft European standard for the design of greenhouses, since slender arches formedfrom a circular hollow steel section tube are used extensively throughout Europe in the production of ‘tunnel greenhouse’, or ‘polytunnel’frames. Slender arches are also used increasingly in garden-centre and emergency-aid structures, as an architectural feature in glazed barrel-vaulted roofs, and for swimming-pool covers. To address the immediate requirement for rational design procedures for slender steel arches used in polytunnel greenhouses, collaborative research involving full-scale collapse testing, determination of tube behaviour, and computational modelling, has been undertaken recently in France and the UK.
Ph. Roux, A.P. Robertson and R. Motro