Numerical modelling of reinforced concrete gravity retaining walls under seismic loads

Abstract

Due to their multiple uses and structural challenges they outline during normal circumstances and seismic events, retaining walls constitute an important concern for civil engineers. Design of these structures requires accurate determination of lateral earth pressure under various conditions. Considering the dynamical action under seismic excitation, the total lateral earth pressure for cohesion-less soil backfills is often estimated by using the Mononobe-Okabe method. Although this conventional method does not take into account the full characteristics of a seism, it has recovered a wide range of applications in practice. It is interesting therefore to compare its predictions to those of a more comprehensive analysis. In this study, a dynamic numerical modelling of reinforced concrete gravity retaining walls with cohesion-less backfill material was conducted using PLAXIS 2D software. Loma Prieta earthquake record was applied and different values of wall height and backfill soil stiffness were considered. Parametric studies were accomplished in order to assess the influence of key parameters on the vertical profile of dynamic active earth pressure and the resultant thrust. A good agreement between the numerically computed seismic lateral force acting on the wall was obtained in comparison with the conventional Mononobe-Okabe approach; however this last may yield oversizing.