Comparative risk assessment of secondary structuresin wide-span timber structures

Secondary structures in wide-span timber roofs are either realized as statically determinate or indeterminate systems. The latter are often preferred since they are more efficient in utilizing the material and enable load distribution in case of a local damage, but they also facilitate progressive collapse. The aim of this study is to compare the performance of different configurations of secondary structures in wide-span timber roofs, with respect to reliability, robustness and risk. To this end, a risk assessment of three configurations is performed by considering (probabilistically) all possible failure scenarios of purlin elements in the roof. In this initial study, failure of the primary beams is not considered. The results show that the static determinate configuration leads to a system that is less sensitive to local damages but has an overall higher risk. It must be further investigated whether this duality is also observed for the full system.