The New Framework for Shell Buckling Design and the European Shell Buckling Recommendations Fifth Edition

Abstract

This paper outlines key aspects of the new European Standard on the Strength and Stability of Metal Shells EN 1993-1-6 with its extended commentary and expansion in the fifth edition of the European Recommendations on Shell Buckling. This European design standard is the first to be strongly oriented toward numerical analyses in design, with clear distinctions between different classes of both analysis and fabrication. It presents a different style of standard: Each limit state is defined in a separate chapter, but all shell geometries are treated and all analysis types are used within each chapter. The strength evaluation criteria differ according to the calculation that has been made. This new structure, with its new paradigm that permits generalization of the design procedure for all thin shells, geometries, load cases, boundary conditions, and qualities, represents a major step forward. It also offers the opportunity for future research studies of shell structures to be undertaken within a coherent conceptual framework that is completely general. The EN 1993-1-6 standard goes a long way toward bridging the gap between the computational engineering mechanics and structural engineering design communities. Unfortunately, this European standard EN 1993-1-6 has a complex and extensive background that cannot be stated within the document so the European Recommendations on Shell Stability, now published in its fifth edition, gives an extensive commentary, many expanded rules, and many additional geometries and load cases that are not formally presented within the standard itself. The development of both EN 1993-1-6 and the recommendations has been the work of the Eurocode shell structures development committee CEN/TC250/SC3/PT4 and the European Convention for Constructional Steelwork committee (ECCS) TWG 8.4. It is presented here by the convener of these two committees. This paper explains the reasoning behind several particular choices that have been taken in developing the standard, occasionally running counter to traditional views. It also identifies several tricky issues that have not been addressed well in the shell buckling literature but that have arisen through the attempts to achieve completely general rules and which need imaginative answers to ensure a fully consistent treatment of all systems. It is hoped that this paper will assist researchers and designers to understand the rules and recommendations and will encourage researchers to undertake and present their work in a manner that permits its rapid adoption into the new standardized design procedures.