1. Professor, Dept. of Civil & Environmental Engineering, Tufts Univ., Medford, MA 02155 (corresponding author).
2. Assistant Structural Engineer, Gill Engineering Associates, Inc., Needham, MA 02494; formerly, Graduate Student, Tufts Univ., Medford, MA 02155.
3. Doctoral Candidate, Dept. of Civil & Environmental Engineering, Tufts Univ., Medford, MA 02155.
4. Associate Professor, Dept. of Civil Engineering, Univ. of New Hampshire, Durham, NH 03824.
5. Professor of Practice, Dept. of Civil & Environmental Engineering, Tufts Univ., Medford, MA 02155; Vice President, Fay Spofford & Thorndike, Burlington, MA 01803.