1. Research Fellow, Dept. of Civil Engineering, Univ. of Porto, 4200-465 Porto, Portugal.
2. Associate Professor, Dept. of Civil Engineering, Univ. of Porto, 4200-465 Porto, Portugal.
3. Assistant Professor, Dept. of Civil Engineering, Univ. of Hong Kong, Hong Kong; formerly, Lecturer, Dept. of Civil, Environmental, and Geomatic Engineering, Univ. College London, London, United Kingdom (corresponding author).