Seismic performance of an existing anchored quay wall in the Ravenna port (Italy)

Evaluating the seismic performance of retaining walls is a significant engineering challenge due to non-linear soil-structure interaction, site response effects and ground motion properties. State of the art methods, based on non-linear dynamic analysis, are nowadays able to give reliable results when the numerical modeling is carried out with careful evaluation of seismic signals and appropriate choice of constitutive relationship for soils. However, a similar analysis is mostly restricted to relevant infrastructures. For large part of the practical situations, the simplified seismic analysis still represents the most used tool for design and verification. The new generation of Eurocode in Europe has introduced some innovations on the use of simplified seismic analyses making them more rationale and site-specific. In this paper, a case study involving the seismic evaluation of an existing anchored sheet-pile quay wall in the Ravenna port is presented. A well-known geotechnical setting and the data from an extensive field and laboratory investigation available for the area, allowed to perform both simplified and non-linear dynamic seismic analyses. The simplified seismic analysis according to the pseudo-static method outlined in the new draft of Eurocode 8 (FprEN1998:2024 TC250 – part 1 and 5), has been carried out and compared with the seismic performance of the quay wall evaluated through a 2D FEM non-linear dynamic analysis. Also, the seismic displacements of the quay wall from 2D FEM non-linear dynamic analysis were compared with recently proposed Newmark-type simplified methods. Relevant aspects of the presented case study are the very deep location of the bedrock, which required a separate model for site response analysis and 2D FEM non-linear dynamic analysis of the structures and the significant length of the wall embedment, due to poor geotechnical properties of the ground, which resulted in a pronounced spatial variation with depth of the ground motion.