Theoretical framework for the seismic design of anchored steel sheet pile walls

Anchored Steel Sheet Pile (ASSP) walls are widely used as retaining structures in wharves and quays as an alternative to gravity concrete walls due to their ease of installation. Their seismic design is based on conventional pseudo-static approaches, often leading to uneconomic solution in high seismic areas. This paper addresses the dynamic behaviour of ASSP walls retaining dry cohesionless backfills, in order to investigate the possible failure mechanisms of the soil-wall system and the resulting permanent displacements. Simple limit equilibrium methods are developed to predict the internal forces in the structural members and to compute the critical acceleration of the soil-wall system, corresponding to which the strength of the soil is completely mobilised. Theoretical predictions are compared with the results of an extensive numerical study, including both pseudo-static and dynamic analyses. The key role of the critical acceleration for the structural and the geotechnical design of ASSP walls is highlighted, controlling both the maximum internal forces and the magnitude and trend of displacements