1. Department of Civil and Natural Resource Engineering, University of Canterbury, Christchurch 8014, New Zealand, sarah.bastin@canterbury.ac.nz
2. Tonkin + Taylor Ltd., 105 Carlton Gore Road, Newmarket, Auckland 1023, New Zealand
3. Department of Civil and Environmental Engineering, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
4. Department of Civil and Environmental Engineering, Virginia Tech, 750 Drillfield Drive, MC 0105, Blacksburg, Virginia 24061