The role of ground motion characters on the dynamic performance of propped retaining structures.

The paper presents the main results of a number of numerical dynamic analyses of propped embedded retaining structures in the time domain. The numerical model entails the static condition of an excavation 4 m height in presence of a pair of retaining cantilever walls in a dry, coarse-grained soil. Afterwards, two structural elements (props) connecting the two opposite walls have been introduced. Four recorded strong-motion acceleration time histories, and four equivalent analytical wavelets, characterized by frequency content rather different have been applied to the bottom of the model. The analyses were carried out considering different maximum accelerations, by scaling the dynamic input. A nonlinear hysteretic soil model coupled with a Mohr-Coulomb strength rule has been adopted. The results of the analyses show the role played by a number of parameters that characterize the seismic signal and the effects of the seismic response on the increment of forces acting on structural elements.