1. Structural Engineer, Stanley D. Lindsey and Associates, Ltd., Atlanta, GA 30339 (corresponding author). E-mail: tyi@sdl-atl.com
2. Assistant Professor, Dept. of Civil, Architectural and Environmental Engineering, Drexel Univ., Philadelphia, PA 19104-2816.
3. Professor, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0355.