Modelling of Jack-up Foundations under Cyclic Loading

1. G.T. Houlsby (Oxford University) and M.J. Cassidy (The University of Western Australia) Modelling of Jack-up Foundations under Cyclic Loading This research is sponsored by the ARC as part of an IREX exchange programme between Oxford University and The University of Western Australia The waves are modelled by “NewWave” theory, which realistically describes an extreme loading event Purpose: to develop realistic models for the foundations of jack-up units when subjected to cyclic combined loads Visit us at www-civil.eng.ox.ac.uk or www.cofs.uwa.edu.au “Model D” uses “continuous hyperplasticity” to describe smooth moment-rotation relationships with increasing non-linearity as the moment is increased The spudcans are modelled by a new theoretical approach called “Model D”, which can describe the response of the foundation when any combination of {V,M,H} loads is applied Example dynamic analysis of a jack-up subjected to a 15m high wave in 90m water depth “Continuous hyperplasticity” is an approach to plasticity theory which has been developed by Prof. G.T. Houlsby and Dr A.M. Puzrin. The main advantage is that the entire theoretical model can be specified by defining just two scalar functionals. The theory can describe models with an infinite number of plastic strain components within a compact theoretical framework The equations required to specify “Model D” are: The graph above shows the load paths for windward and leeward footings. Below is the moment-rotation response for the windward footing where