Calculation of foundation uplift effects using a numerical Laplace transform

A Laplace domain technique to calculate non-linear foundation uplift effects is presented. Analysis in the Laplace domain permits the modelling of the building structure more precisely by using continuous mass models. Different damping models for every single finite element of the sturcture can easily be utilized via the correspondence principle. Moreover, it is possible to use the substructure method, which permits the modelling of the soil and the building structure separately by different methods. Using, e.g. the boundary element method for the soil, the damping mechanism caused by waves travelling away from the foundation (geometric damping effects) is implicitly included. The model can be condensed to the relevant degrees of freedom of the structure. Two illustrative numerical examples demonstrate the applicability of the method presented.

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