1. Geotechnical Engineer, WorleyParsons, Level 6, QV1 Building, 250 St. Georges Terrace, Perth, WA 6000, Australia. E-mail: manh.tran@worleyparsons.com
2. Professor, Centre for Offshore Foundation Systems, Univ. of Western Australia, WA 6009, Australia (corresponding author). E-mail: randolph@civil.uwa.edu.au
3. Associate Professor, School of Civil Engineering, Univ. of Sydney, NSW 2006, Australia. E-mail: d.airey@civil.usyd.edu.au