1. Research Associate, Centre for Offshore Foundation Systems, Univ. of Western Australia, M053 Fairway, Crawley, WA 6009, AU (Corresponding author), e-mail: sam.stanier@uwa.edu.au
2. Winthrop Professor, Centre for Offshore Foundation Systems, Univ. of Western Australia, M053 Fairway, Crawley, WA 6009, AU.