A one-dimensional elasto-viscoplastic macro-element model for creep analysis of shallow foundations on sand

Footings on sand can exhibit considerable long-term creep settlement. However, most settlement prediction methods account for creep by using either a reduced long-term equivalent sand stiffness or applying an arbitrary time correction factor. In this paper, a novel elasto-viscoplastic macro-element model for shallow foundations on sand under vertical loading is developed that provides a simple and efficient tool for footing settlement prediction explicitly accounting for creep in a realistic manner. By incorporating an isotach relationship postulated for the load-settlement behaviour of shallow foundations on sand, the macro-element is constructed based on the non-stationary flow surface theory and the time effect is incorporated using visco-plasticity. The proposed model, which requires only three input parameters, is shown to be capable of satisfactorily reproducing the loadsettlement responses of footings tested in the field and in the geotechnical centrifuge at typical working loads. The proposed model can also reproduce effects seen in practice such as post-creep stiffening and settlements induced by unload-reload cycles.

Automated summary

This paper introduces a novel elasto-viscoplastic macro-element model for shallow foundations on sand, which explicitly accounts for creep in a realistic manner. The model is capable of reproducing load-settlement responses of footings tested in the field and in the geotechnical centrifuge at typical working loads, as well as effects seen in practice such as post-creep stiffening and settlements induced by unload-reload cycles.