Evaluation of the pseudo-dynamic bearing capacity of surface footings on cohesionless soils using finite element lower bound limit analysis

Design of shallow foundations subjected to dynamic loading is an important topic in the geotechnical engineering practice. In this study, an attempt has been made to evaluate the seismic bearing capacity of a strip footing founded on a soil deposit using the lower bound limit analysis method merged with the finite element formulation adopting the second-order conic programming (SOCP) approach. To this end, a well-established pseudo-dynamic loading scheme has been employed to apply the seismic loading on the surface footing. Accounting for the various conditions of the underlying soil layer, the results of the so-called 'conventional pseudo-dynamic (CPD)', `spectral pseudo-dynamic (SPD)' and 'modified pseudo-dynamic (MPD)' bearing capacity analyses are compared with one another and their pseudo-static counterparts in terms of the value of N. parameter. The results show the notable influence of the amplification factor, the impedance factor and the site characteristics on the seismic bearing capacity of shallow foundations. In addition, the results obtained from the MPD, CPD and SPD methods are observed to bear a good agreement with each other. Moreover, the MPD approach was observed to render the most conservative seismic bearing capacity values.