1. Senior Structural Engineer, Simpson, Gumpertz, and Heger, Inc., 41 Seyon St., Waltham, MA 02453; formerly, Graduate Research Assistant, School of Civil and Environmental Engineering, Georgia Institute of Technology.
2. Graduate Research Assistant, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332.
3. Professor, School of Civil and Environmental Engineering, Georgia Institute of Technology, 790 Atlantic Dr., Atlanta, GA 30332-0355 (corresponding author).
4. Professor, School of Civil and Environmental Engineering, Georgia Institute of Technology, 790 Atlantic Drive, Atlanta, GA 30332-0355.