1. Research Assistant, Dept. of Building, National Univ. of Singapore, 4 Architecture Dr., Singapore 117566.
2. Associate Professor, Dept. of Building, National Univ. of Singapore, 4 Architecture Dr., Singapore 117566 (corresponding author).
3. Professor, Dept. of Civil and Environmental Engineering, Univ. of California, 213 McLaughlin Hall, Berkeley, CA 94720.
4. Assistant Professor, Dept. of Building, National Univ. of Singapore, 4 Architecture Dr., Singapore 117566.
5. Professor, Dept. of Building, National Univ. of Singapore, 4 Architecture Dr., Singapore 117566.