Influence of Soil Non-linear Behaviour on the Selection of Input Motion for Dynamic Geotechnical Analysis

Non-linear dynamic analyses represent a useful tool for the assessment of the seismic response of geotechnical systems. This kind of analyses requires the selection of strong motion records which reflects the seismic hazard at the site of interest. In this regard, international seismic codes prescribe the satisfaction of some compatibility criteria between the selected records and a target elastic response spectrum, in a specific interval of vibration periods, with reference to structural features. However indication for the choose of an appropriate range of vibration periods for geotechnical systems is lacking in current design codes. A procedure for the selection of strong motion records with indications on interval of vibration periods to be considered for geotechnical problems, was recently proposed by the author and co-workers. This paper highlights how the non-linear behaviour of the soil deposit, represents only the starting point of an iterative process useful for fully non-linear dynamic analysis. Specifically, an application of the novel procedure shows how it’s possible to exploit the new selection method as an immediate and simple tool for the selection of input motions for 1-D Equivalent Linear and Non-Linear seismic site response analysis.