1. Research Assistant, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 205 N. Matthews Ave, Urbana, IL 61801, US, e-mail: castane6@illinois.edu
2. Research Assistant, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 205 N. Matthews Ave, Urbana, IL 61801, US, e-mail: jhensche@illinois.edu
3. Professor, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 205 N. Matthews Ave, Urbana, IL 61801, US, e-mail: dlange@illinois.edu