1. Dept. of Civil and Environmental Engineering, Univ. of Illinois, 2145 Newmark Civil Engineering Bldg, 205 N. Mathews, Urbana, IL 61801-2352 US, e-mail: yusong3@illinois.edu
2. Dept. of Civil and Environmental Engineering, Univ. of Illinois, 2145 Newmark Civil Engineering Bldg, 205 N. Mathews, Urbana, IL 61801-2352 US, e-mail: rzou3@illinois.edu
3. Dept. of Civil and Environmental Engineering, Univ. of Illinois, 107 West Annex, San Angelo, TX 76904 US, e-mail: castane6@illinois.edu
4. Dept. of Civil Engineering, Kansas State Univ., 2107 Fiedler Hall, Manhattan, KS 66506-5000 US, e-mail: riding@ksu.edu
5. Dept. of Civil and Environmental Engineering, Univ. of Illinois, 2129b Newmark Civil Engineering Bldg, 205 N. Mathews, Urbana, IL 61801-2352 US, e-mail: dlange@illinois.edu