‘Skipped cycles’ method for studying cyclic loading and soil–structure interface

This paper deals with a numerical calculation method related to the modelling of soil–structure interfaces subjected to a large number of cyclic loadings. The first part of the paper focuses on the presentation of a ‘skipped cycles’ method to reduce time computation without influencing the calculation precision of strains and stresses. This method is based on an extrapolation of the plastic strains calculated during the previous loading cycles. The second part of the paper presents the numerical validation of the ‘skipped cycles’ method. A constitutive model for soil–structure interfaces subjected to cyclic and transient loads is briefly presented. The capabilities of this model to take into account cyclic phenomena like softening or hardening and shakedown or ratcheting are illustrated by several academic examples. The performance of the ‘skipped cycles’ method is then studied through two examples including, on the one hand, a shearing resistance test with four interface elements, and on the other hand, an axially loaded pile with sixty interface elements. The results are compared with those obtained by means of a classical ‘step by step’ method and show that the ‘skipped cycles’ method provides significant reduction in terms of time computation without lowering the numerical calculation precision.