Shell Analysis and its Use in Design within the Framework of the new European Standards

Shell Analysis and its Use in Design within the Framework of the new European Standards

Abstract

This presentation concerns the design of civil engineering shell structures within the framework of design to structural engineering standards, with special reference to the new Eurocode 3 Part 1.6 Strength and Stability of Shell Structures.

There is a huge literature on the analysis of shell structures, covering linear elastic, plastic, stability and collapse analyses. For civil engineering construction, design must normally be performed with reference to a standard, either national or international. However, there is often a large gap between the design rules in a standard on shell structures (e.g. ACI 334) and the sophistication of the analyses presented in the research literature. Thus, it is difficult to see how more sophisticated analyses may be exploited in the design process.

Now for the first time, an international standard on metal shell design (Eurocode 3 Part 1.6, 1999) has been written in a manner that accommodates all forms of analysis. Moreover, this standard has carefully defined the way in which the results of each kind of analysis should be interpreted to ensure that the safety and reliability of the structure are appropriately maintained. This seminar describes features of this new standard, and proposes it as a valuable vehicle for researchers who wish to develop new design rules and for designers who wish to use more sophisticated analyses to obtain the most economic structure or to perform the most rigorous assessments of existing structures.

A key feature of the new European standard is that it attempts to accommodate all forms of static structural analysis within the framework of the same design philosophy. To achieve this goal, it must address questions of plasticity, stability and imperfection sensitivity within the framework of a reliability assessment using partial safety factors on both loading and structural strength, the latter including modified factors according to the mode of failure. These are matters that are not normally considered within analysis remit of applied mechanics, so a presentation of the draft standard framework should provide a valuable perspective to the developers and users of advanced analysis.