1. Structural Engineer, Bridge Diagnostics, Inc., 1965 57th Ct., Boulder, CO 80301-6268. E-mail: jesseg@bridgetest.com
2. Analysis and Software Engineer, Bridge Diagnostics, Inc., 1965 57th Ct., Boulder, CO 80301-6268. E-mail: commander@bridgetest.com
3. Associate Professor, Dept. of Civil and Environmental Engineering, Univ. of South Carolina, 300 Main St., Columbia, SC 29208, 803 777 0671 (corresponding author). E-mail: ziehl@engr.sc.edu