- 2795 - Direct Displacement-Based Design of Embedded Retaining Structures Elisabetta Cattoni Assistant Professor University e-Campus, Novedrate (CO), Italy e-mail: elisabetta.cattoni@uniecampus.it Manuela Cecconi Assistant Professor University of Perugia, Italy e-mail: ceccon@unipg.it Vincenzo Pane Professor University of Perugia, Italy e-mail: panev@unipg.it ABSTRACT The paper presents the displacement seismic design method known as Direct Displacement – philosophy behind DDBD is that structures – including geotechnical structures – should be designed to achieve a specified performance level under a specified seismic intensity. The calculation steps of the method are described in detail with considerable discussion on their applicability to cantilever and anchored retaining structures. As a final result, the DDBD procedure provides a rational design approach which relies on a convenient reduction of seismic thrusts based on the system capacity of dissipating energy (ductility capacity). KEYWORDS: retaining structures, seismic design, equivalent damping, thrust reduction curve. BACKGROUND AND MOTIVATION OF THE STUDY In recent years, performance-based approaches for earthquake engineering evaluation and structural design have been proposed in the literature (Priestley, 1993; Priestley, 2003; Priestley et al., 2007) in the dual attempt to mitigate some of the deficiencies in current force-based design methods on one hand, and improve the reliability of the system by more directly comparing computed response and expected structural performance on the other hand. This motivation has led to the development of a large number of alternative seismic design methods based mainly on deformation capacity rather than strength capacity and generally termed “performance-based” design methods. According to the philosophy of these methods, civil engineering structures -