Seismic uplift capacity of shallow strip anchors: A new pseudo-dynamic upper bound limit analysis

Abstract

Using a new pseudo-dynamic approach for the inclusion of seismic body forces, the seismic vertical uplift capacity of horizontally placed strip plate anchors in sand at shallow depths has been computed with the application of upper bound theorem of limit analysis. Unlike the earlier pseudo-dynamic approaches, in this study, the nonlinear variation of both horizontal and vertical acceleration along the depth of soil layer, and in the values of amplitude and phase of accelerations has been considered with the satisfaction of stress boundary condition at the ground surface. The seismic uplift factor Fγs due to the unit weight of soil for different combinations of seismic acceleration coefficients, internal friction angle of soil, and the embedment ratio of anchors has been obtained. The solutions indicate that the magnitude of Fγs decreases substantially with an increase in seismic acceleration coefficients; whereas as expected, increases with an increase in embedment ratio of anchors and soil friction angle. This study produces the least upper bound solutions in comparison to the earlier reported results in the literature.