STUDY OF THE DYNAMIC RESPONSE OF LARGE SCALE BUILDINGS USING SIMPLIFIED APPROACHES
Olivier Loiseau, Karine Cheval, Bruno Autrusson, Didier Brochard, ASME Pressure Vessels and piping, Cleveland (USA), 21-24 juillet 2003
The dynamic response of large scale concrete buildings submitted to an explosion cannot always be obtained by means of classical FE analysis codes at reasonable costs. Indeed, the precision level required to predict efficiently the local failure of structural elements needs very fine meshes, which rapidly becomes unaffordable especially in the case of dynamics. The approach presented in this paper relies on a partitioning of the phenomena and their study by simplified methods: (1) The loading of the structure resulting from the detonation of an explosive charge is computed by a numerical implementation of semi-empirical formulas (Kinney and Graham, 1985, Baker et al., 1983) ; (2) The response of external walls elements, directly impacted by the aerial shock wave, is studied by a modal projection method, based on the use of analytical solutions from the thin plate theory ; (3) Longitudinal propagation of the shock through the floors and walls of the building, including material and structural damping, is modeled by a 1D approach. This allows to determine finally whether the resistance limit of the constituting material is locally exceeded or not. Examples taken from a representative building study are presented in order to illustrate the approach.