1. Professor, Dept. of Civil Engineering, Taegu Univ., Kyongsan, Kyongbuk, 712-714, Korea.
2. Assistant Professor, Dept. of Civil Engineering, Kansan Univ., Kunsan, Jeonbuk, 573-701, Korea.
3. Professor, Dept. of Civil and Environmental Engineering, Univ. of California, Irvine, CA 92697-2175.
4. Professor, Dept. of Civil Engineering and Construction, North Dakota State Univ., Fargo, ND 58105.