1. Professor of Civil Engineering, College of Civil Engineering, Southeast Univ., Nanjing 210096, P. R. China.
2. Reader, Institute for Infrastructure and Environment, The Univ. of Edinburgh, Edinburgh, U.K. (corresponding author). E-mail: J.F.Chen@ed.ac.uk
3. Ph.D. Research Student, College of Civil Engineering, Southeast Univ., Nanjing 210096, P. R. China.
4. MSc Research Student, Collage of Civil Engineering, Southeast Univ., Nanjing 210096, P. R. China.