1. Research Scientist, Dept. of Civil, Construction, and Environmental Engineering, Iowa State Univ., 353 Town Engineering Bldg., Ames, IA 50011. E-mail: rangan@iastate.edu
2. Professor Emeritus, Dept. of Civil Engineering, Univ. of Illinois at Urbana-Champaign, 205 N. Mathews, NCEL Rm. 1215, Urbana, IL 61801. E-mail: mrthomps@uiuc.edu