1. Ph.D. Student, Dept. of Civil and Structural Engineering, Univ. of Sheffield, Sir Frederick Mappin Bldg., Mappin St., Sheffield S1 3JD, U.K. (corresponding author).
2. Senior Scientist, Dept. of Industrial Engineering, Univ. of Padua, Via Marzolo 9, 35131 Padua, Italy.
3. Lecturer, School of Mechanical, Aerospace and Civil Engineering, Univ. of Manchester, Oxford Rd., Manchester M13 9PL, U.K.
4. Professor, Dept. of Civil and Structural Engineering, Univ. of Sheffield, Sir Frederick Mappin Bldg., Mappin St., Sheffield S1 3JD, U.K.
5. Associate Professor, Dept. of Industrial Engineering, Univ. of Padua, Via Marzolo 9, 35131 Padua, Italy.