The seismic design for offshore foundations is based predominantly on experience onshore. This paper describes the results of dynamic centrifuge tests performed to validate the performance of a suction caisson installed in normally consolidated clay. The main objective is to evaluate the likely plastic displacement under different shaking levels. Permanent displacement results indicate that the displacements experienced are well within the allowable movement for the foundation considered, even though a strength based design approach would consider this to be a failure. Larger earthquakes are seen to produce comparatively smaller displacements. It is concluded that the when designing for seismic loading, if some displacement is permissible then a performance-based approach allowing some displacement proves significantly less conservative than a purely strength-based design. It is also concluded that dynamic response analyses should consider the strength of soil, as this can act as a fuse against large amplitude shear waves.
|Title of host publication||Frontiers in Offshore Geotechnics II - Proceedings of the 2nd International Symposium on Frontiers in Offshore Geotechnics|
|Number of pages||6|
|Publication status||Published - 1 Jan 2011|
Brennan, A. J., Madabhushi, S. P. G., & Cooper, P. (2011). Seismically-induced displacements of a suction caisson in soft clay. In Frontiers in Offshore Geotechnics II - Proceedings of the 2nd International Symposium on Frontiers in Offshore Geotechnics (pp. 711-716)