1. Assistant Professor, Dept. of Civil Engineering and Environmental Science, Univ. of Oklahoma, 202 W. Boyd St., Rm. 334, Norman, OK 73019. E-mail: acerato@ou.edu
2. Professor and Dept. Head, Dept. of Civil and Environmental Engineering, Univ. of Massachusetts, 18 Marston Hall, Amherst, MA 01003. E-mail: lutenegg@ecs.umass.edu