1. Associate Professor, Dept. of Civil and Environmental Engineering, Louisiana State Univ. at Baton Rouge, 3418H Patrick F. Taylor Hall, Nicholson Extension, Baton Rouge, Louisiana 70803.
2. Assistant Professor, School of Architecture and Design, Univ. of Camerino, Viale della Rimembranza, 63100 Ascoli Piceno, Italy.
3. Professor, Dept. of Structural Engineering, Univ. of California at San Diego, 9500 Gilman Drive, La Jolla, California 92093-0085 (corresponding author).