1. Postgraduate, School of Civil and Environmental Engineering, The Univ. of Adelaide, Adelaide, SA5005, Australia. E-mail: iliu@civeng.adelaide.edu.au
2. Professor, School of Civil and Environmental Engineering, The Univ. of Adelaide, Adelaide, SA5005, Australia (corresponding author). E-mail: doehlers@civeng. adelaide.edu.au
3. Associate Professor, Dept. of Civil, Construction and Environmental Engineering, North Carolina State Univ., NC 27695–7533. E-mail: rudi seracino@ncsu.edu