1. Doctoral Candidate, School of Civil, Environmental and Architectural Engineering, Korea Univ., Anam-dong, Seongbuk-gu, Seoul 136-713, Korea.
2. Professor, School of Civil, Environmental and Architectural Engineering, Korea Univ., Anam-dong, Seongbuk-gu, Seoul 136-713, Korea (corresponding author).
3. Research Associate, Dept. of Civil Engineering and Applied Mechanics, McGill Univ., Montreal, QC, Canada H3A 0C3.
4. Professor, Dept. of Civil Engineering and Applied Mechanics, McGill Univ., Montreal, QC, Canada H3A 0C3.