Ancient roof structures: capacity of battens and reapir using wood-based panels

The erection of ancient roof structures was based on the experience, tradition and the courage of their constructors instead of a structural analysis. A realistic model requires the consideration of the spatial load-bearing behaviour, as well as the flexibilities and the eccentricities of carpentry joints. However, the utilization ratios of roof
structures yield high values, so no meaningful statement about the load-bearing capacity of these structures can be made. By using the "Grazer Dachstuhl" as an example, changes of the utilization ratios as a consequence resulting from the consideration of the capacity of the roof battens are pointed out. In the beginning, some theoretical background on the load-bearing capacity of roof battens is presented. This is followed by a report of some structural tests
and the documentation of a model calculation. Based on the findings of the analysis of ancient roof structures, a protecting repair-concept using wood-based panels will be developed. This integral structure comprises the improvement of the rafter roof, a strengthening of the rafters themselves and their bases and an in plane-bracing of the roof. Additionally, this concept is characterised by economical, constructural and building-physical advantages