| Popis: |
The robustness of structures in general and the robustness of timber structures is of great interest. This paper presents some research results concerning the probabilistic robustness assessment and influence of material ductility on the robustness of timber truss systems. The robustness analysis in this research project is based on the general probabilistic framework. It must be noted that probabilistic values of strength parameters of timber are obtained from experimental testing. The main difference with respect to previous work is that in this paper the robustness of the different structural systems is assessed by a newly proposed robustness measure named the robustness factor for normed failure probability of a system. Beside this robustness measure, a measure named robustness index for normed reliability is presented. The first step in this investigation is evaluation, of brittle models with respect to robustness. Six different structural systems, widely used in timber engineering, are considered. These different structural systems are analysed and compared with respect to robustness and a general conclusion concerning robustness of the whole structure is given. Conclusions relating to current probabilistic models of the laminated timber based on the experiments conducted are given. Also, based on these experiments, conclusions relating to the behaviour in bending and compression parallel to the grain is given. Finally, taking into account ductility in compression and real probabilistic parameters of the mechanical properties, the robustness assessment is made and compared to a brittle model. It can be concluded that for parallel systems, the influence of ductility can be significant. |
