1. Professor, Dept. of Civil and Construction Engineering, National Taiwan Univ. of Science and Technology, 43 Keelung Rd., Daan District, Taipei 106, Taiwan.
2. Ph.D. Candidate, Dept. of Civil and Construction Engineering, National Taiwan Univ. of Science and Technology, 43 Keelung Rd., Daan District, Taipei 106, Taiwan; and Lecturer, Dept. of Civil Engineering, Petra Christian Univ., 121-131 Siwalankerto, Surabaya 60236, Indonesia.
3. Ph.D. Candidate, Dept. of Civil and Construction Engineering, National Taiwan Univ. of Science and Technology, 43 Keelung Rd., Daan District, Taipei 106, Taiwan (corresponding author).