Displacement-based seismic design of a shallow strip footing positioned near the edge of a rock slope

This paper presents a displacement-based dynamic design of shallow strip footings located close to the edge of homogeneous and isotropic rock slopes. The analysis is conducted using the “generalized tangential” technique in which the Hoek–Brown strength is replaced by an “optimal” tangential Mohr–Coulomb domain within the framework of the kinematic approach of limit analysis theory. In order tobetter understand the influence of these factors including geometrical features, rocks trength para-meters and seismic loading, a parametric study is carried out. An expression is derived and used toobtain a least upper bound solution for the bearing capacity of a footing on a rock slope considering a kinematically admissible log-spiral failure mechanism. Inaddition,a similar expression of the horizontalyield seismic coefficient is derived for a given load acting on the foundation.The assessment of earthquake-induced permanent displacement is performed by a simplifiedprocedure. This requires the knowledge of a ground motion parameter that can be evaluated by site-specific seismic hazard analyses or ground motion prediction equations and that considers the actualsliding surface. The calculated displacement should not be greater than a selected limiting tolerabledisplacement for the specific case. An example is presented illustrating the application of the designprocedure for the bridge foundations.