1. Research Professor, Research Center for Disaster Prevention Science and Technology, Korea Univ., Seoul 136-713, Korea.
2. Assistant Professor, Dept. of Civil Engineering, Kyung Hee Univ., 1732 Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 17104, South Korea.
3. Professor, School of Civil, Environmental and Architectural Engineering, Korea Univ., Anam-ro 145, Seongbuk-gu, Seoul 136-713, South Korea (corresponding author).