Kinematic interaction between retaining walls and retained footings under dynamic loading Interaction cinématique entre les murs de soutènement et les fondations conservées sous chargement dynamique George Papazafeiropoulos 2 , Prodromos N. Psarropoulos 3 and Yiannis Tsompanakis 1 1 Technical University of Crete, Greece 2 Hellenic Air Force & Technical University of Crete, Greece 3 Hellenic Air-Force Academy, Greece ABSTRACT In this study the kinematic soil–foundation interaction problem for a massless surface strip footing retained by a wall is ex- amined. Transfer functions for horizontal, vertical and rocking response of the foundation are evaluated via two different ap- proaches that utilize the finite element method. Satisfactory agreement is shown to exist between them. Moreover, the vertical and rocking accelerations of the foundation are compared to its horizontal acceleration. It is shown that the presence of the re- taining wall alters substantially the foundation response and introduces significant vertical and rocking motion. RÉSUMÉ Cette étude examiné le problème de la cinématique interaction entre le sol et la fondation en cas d'une fondation superficielle sans masse retenue par un mur. Les fonctions de transfert pour la réponse horizontale, verticale et basculement de la fondation sont évaluées à deux approches différentes qui utilisent la méthode des éléments finis. Un accord satisfaisant à exister entre eux. En outre, les accélérations verticales et les accélérations du basculement de la fondation sont comparées à son accélération hori- zontale. Il est montré que la présence du mur de soutènement modifie considérablement la réponse de la fondation et instaure importants mouvements verticaux et à bascule. Keywords: Kinematic interaction, dynamic response, retaining walls, footings, soil-foundation interface. 1 Corresponding Author. 1 INTRODUCTION One of the most usual assumptions made regard- ing the seismic motion at the soil surface is that it is spatially invariant; this means that various points are excited synchronously and experience the same free-field motion (FFM). This situation refers to the motion at the soil-foundation inter- face when no structure is present. Foundation in- put motion (FIM), which is the motion expe- rienced by the foundation of a structure when both the foundation and the superstructure are assumed massless, is certainly different from the free-field motion. FFM is mainly comprised of horizontal motion components, while FIM is likely to include horizontal, vertical, rocking and torsional motions that depend on the mechanical and geometrical characteristics of the foundation and the soil. The difference in the response of the structure computed for FIM and the correspond- ing one derived from FFM is the so-called kine- matic interaction (KI) effect. Note that seismic norms worldwide ignore that effect, assuming that FIM and FFM are identical.