1. Professor, School of Civil Engineering, Purdue Univ., 550 Stadium Mall Dr., West Lafayette, IN 47907-2051. E-mail: rodrigo@ecn.purdue.edu
2. Assistant Professor, School of Civil Engineering, Purdue Univ., 550 Stadium Mall Dr., West Lafayette, IN 47907-2051. E-mail: mprezzi@ecn.purdue.edu