16 Février – Thesis defense - Yann Sousseau

14 h Amphi 3 - building A9 (University of Bordeaux - Talence campus)

Similitude laws and mechanical behavior modeling of multi-storey timber buildings: contributions, limits and uncertainty.

Static and dynamic behaviours of high-rise timber buildings are complex, only experiment allows to obtain a reliable estimate. Tests on real scale are complex, if not impossible to achieve. The proposed solution in this work consists in testing representatives reduced scales models, whose design is based on similitude laws. From the observed behaviour on reduced scales, these similitude laws allow to deduce that at full scale. Similitude laws are composed by a set of similitude factors. These factors link parameters or variables of interest of reduced structure with those of initial structure. Similitude laws were very little used in civil engineering, and inexistent in timber construction. This thesis aims to constitute similitude factors for static and dynamic behaviours of a bracing timber system. To this end, experimental, analytic and numerical approaches are employed. Furthermore, through a multi-scale procedure, similitude factors are established to connections, then to the whole structure.
Static and dynamic tests were performed, on 1, 1/2 and 1/3 scales. Experimental similitude factors were so obtained. They were also determined by analytical methods, for connections then for the structure. The no linear behaviour of timber connections was taken into account. Then analytical factors were compared with the experimental ones. Limitations of analytical approach are identified. Considering these limitations, numerical models were developed. As experimental factors, numerical similitude factors differ from analytical factors, when distorsion of similarity is present. Effect of distorsion on numerical factors was analysed through a set of parametric studies.
Input parameters are subject to incertainty : variability of properties of structure constituent elements (connections,...), measurement incertainties,... Therefore a study of propagation of incertainty on variables of interest was carried out, in order to quantify its effects on similitude laws.

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