1. Research Geotechnical Engineer, Turner-Fairbank Highway Research Center, 6300 Georgetown Pike, McLean, VA 22101-2296, US, e-mail: mike.adams@dot.gov
2. Professor, Dept. of Civil and Environmental Engineering, Holmes Hall 383, 2540 Dole St., Honolulu, HI 96822, US, e-mail: ooi@eng.hawaii.edu
3. Research Geotechnical Engineer, Turner-Fairbank Highway Research Center, 6300 Georgetown Pike, McLean, VA 22101-2296, US, e-mail: jennifer.nicks@dot.gov