1. School of Civil and Environmental Engineering, Georgia Inst. of Technology, 790 Atlantic Drive, Atlanta, GA 30332 US
2. Univ. Paris-Est, Laboratoire Navier (UMR 8205), CNRS, ENPC, IFSTTAR, F-77455 Marne-la-Vallée, FR
3. School of Civil and Environmental Engineering, Georgia Inst. of Technology, 790 Atlantic Drive, Atlanta, GA 30332 US (Corresponding author), e-mail: kkurtis@ce.gatech.edu