1. Asst. Prof., School of Civ. Engrg. and Environmental Sci., Univ. of Oklahoma, Norman, Okla. 73019
2. Assoc. Prof., Dept. of Civ. Engrg., Wayne State Univ., Detroit, Mich. 48202.
3. Research Asst., Dept. of Civ. Engrg., Wayne State Univ., Detroit, Mich. 48202