1. President, FYS Advisory, Inc., Chicago, IL 60657.
2. Associate Professor, Kyungpook National Univ., School of Architectural and Civil Engineering, 1370. Sangyegk-Dong, Buk-Gu, DaeGu, 702-701, Korea (corresponding author).
3. Professor, Illinois Inst. of Tech., Dept. of Civil and Architectural Engineering, Chicago, IL 60616.