Robustness of large-span timber roof structures - Two examples

This paper discusses the robustness of large-span timber roof structures, based on findings from failures of two roof structures. One is the Siemens arena in Ballerup, Denmark and the other the Bad Reichenhall ice-arena in Germany. The structures are described as well as the flaws that are believed to have caused the failures. The two cases serve as examples of different design strategies for large-span timber roof structures and the consequences of such strategies for robustness. It is demonstrated that robustness is not a straightforward concept because the best strategy depends on the cause of the failure - which is obviously not known during planning and design.