Lateral soil stiffness adjacent to deep integral bridge abutments

Our understanding of the performance of integral bridge abutments subjected to cyclic loading has been improved using well-designed laboratory experiments, and by observation of abutment performance in the field. However, there remains significant uncertainty on how the increase in lateral stress that arises due to cycling of the backfill may be assessed for abutment design. Such uncertainty is addressed in this paper by drawing on results from a series of experiments performed using the University of Western Australia (UWA) beam centrifuge. The experimental results shed light on the effects, for granular backfill, of initial density, retained height, cyclic history and particle shape. These results, as well as observations made from tests involving overconsolidated clays, are used in conjunction with the existing database of lateral stress measurements to assist in the development of recommendations for assessment of design lateral stresses on deep integral bridge abutments.