1. Rapp Foundation Presidential Associate Professor, School of Civil Engineering and Environmental Science, Univ. of Oklahoma, 202 W. Boyd St., Room 334, Norman, OK 73019, US, e-mail: acerato@ou.edu
2. Rapp Foundation Presidential Professor, School of Civil Engineering and Environmental Science, Univ. of Oklahoma, 202 W. Boyd St., Room 334, Norman, OK 73019, US, e-mail: gamiller@ou.edu