Seismic Performance of Multi-propped Retaining Structures

The performance of retaining walls with multiple levels of props are typically evaluated numerically since it is a typical soil-structure interaction problem which cannot be expressed in a closed form. Under seismic conditions, the soil-structures interaction problem may require the evaluation of the permanent displacements or deformations developing to dissipate the earthquake energy through the formation of some possible kinematic mechanism. The latter cannot occur for multi-propped retaining structures unless yielding of one or more structural elements is achieved. In this paper, the dynamic behavior of a multi-propped embedded retaining structures is studied varying the characters of the input seismic motion. For this purpose, the results of several numerical dynamic analyses, carried out under plane-strain conditions and in the time domain, are presented and discussed. The results of the analyses indicate a very complex response of the system due to the effects of local seismic response and soil-structure interaction phenomena. However, it was possible to identify the main characters of motion that influence the system’s response in terms of resulting actions on structural elements. In particular, the analytical relationships presented in this work confirm that the effect of the frequency content of the seismic input compared to the natural frequencies of the soil profile and the geometry of the system are dominant. While peak ground acceleration seems to be appropriate to estimate the maximum (and instantaneous) increase of bending moments, Arias intensity seems to be a more effective parameter in order to evaluate the residual post seismic bending moment