1. Graduate Research Assistant, Department of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 205 North Mathews Avenue, Urbana, IL 61801 US, e-mail: cchini2@illinois.edu
2. Graduate Research Assistant, Department of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 205 North Mathews Avenue, Urbana, IL 61801 US, e-mail: jfwalla2@ilinois.edu
3. Assistant Professor, Department of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 205 North Mathews Avenue, Urbana, IL 61801 US, e-mail: cjr@illinois.edu
4. Research Assistant Professor, Department of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 205 North Mathews Avenue, Urbana, IL 61801 US, e-mail: peschel@illinois.edu