1. Assistant Professor, Dept. of Building and Construction, City Univ. of Hong Kong, Tat Chee Ave., Kowloon, Hong Kong (corresponding author). E-mail: yuwang@cityu.edu.hk
2. Professor, School of Civil and Environmental Engineering, Hollister Hall, Cornell Univ., Ithaca, NY 14853-3501. E-mail: fhkl@cornell.edu